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Last updated on 13 June 2009

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The image shown above is of a widescreen LCD (liquid crystal display), flat-panel monitor for a desktop PC, also known as a TFT (Thin Film Transistor) monitor - especially when naming the kind of screen used in laptop/notebook computers.

A flat-panel monitor, is flat at the front and at the back (it doesn't have the large, protruding back area that CRT monitor's have). The image below is of a standard CRT (cathode ray tube) monitor. CRT computer monitors are becoming ever-increasingly difficult to buy new. However, as outgoing technology, they are easy to buy second-hand.

NEVER OPEN A CRT MONITOR OR CRT TELEVISION SET. ITS CAPACITORS CAN CARRY A LETHAL CHARGE LONG AFTER IT HAS BEEN SWITCHED OFF!

LCD/TFT computer monitors

Introduction

The table below shows the basic specifications that should be taken into consideration before you purchase an LCD computer monitor. They, and other specifications, will be explained on this page.

Liquid Crystal Display (LCD) flat-panel desktop computer monitors and laptop/notebook computer screens are either non-TFT or TFT displays. Virtually all of the current LCD monitors are TFT LCD monitors. For more information on the non-TFT (passive matrix) and TFT (active matrix) technology visit:

Liquid Crystal Display - http://en.wikipedia.org/wiki/Liquid_crystal_display

TFT LCD - http://en.wikipedia.org/wiki/TFT_LCD

Since virtually all LCD monitors (and notebook computer screens) are now TFT LCD displays, I will just use the term LCD to describe them.

LCD monitors/displays come in several types - TN, IPS, MVA, PVA, PSV - each of which has its own strengths and weaknesses - Read about them here:

Thin film transistor liquid crystal display [TFT LCD] -

http://en.wikipedia.org/wiki/TFT_LCD

For example, TN LCDs are lower-end inexpensive monitors with fast response times (the screen refreshes it images rapidly) and typically narrow viewing angles, although some have better viewing angles than others. If the viewing angle is low, the quality of the graphics display deteriorates as the viewing angle from the centre of the screen increases. To test the viewing angle of a screen, move your head from the centre in front of the screen towards the sides of the screen. IPS LCDs are high-end monitors with the best viewing angle and reasonably fast response times and are the best for high-end graphics work. The trade off is that they are much more expensive than the other types.

Most new desktop computers - even budget models - now come equipped with LCD monitors , but CRT monitors can still be purchased new at bargain prices, or second-hand, as they head towards extinction.

All except the cheapest desktop PCs now come with widescreen LCD monitors, which are ideally suited for watching (widescreen) movies, moreover, it feels more comfortable when working with panoramic photos and expansive spreadsheets. Standard CRT and LCD screens have an aspect ratio of 4:3 (width 4, height 3), which makes them almost square, and widescreen CRT and LCD usually have an aspect ratio of 16:9, which makes them rectangular, as shown in the two images of LCD (rectangular) and CRT (square) screens at the top of the page.

The aspect ratio and the screen size determines the screen/display resolution. For example, an LCD widescreen monitor with 19" screen size and an aspect ratio of 16:9 has a 'native' screen resolution of 1440X900 pixels. The 'native' resolution changes to 1680x1050 pixels for a 20" widescreen monitor with the same aspect ratio of 16:9.

The operating system, usually a version of Windows, queries the monitor's EDID (Extended Display Identification Data), stored on a microchip, via the computer's graphics card, to find out what the monitor's specifications are. Windows can then determine what the range of available screen resolutions and refresh rates are.

The free EDID Viewer provides comprehensive information about the identity and capabilities of an LCD monitor/display.

If your PC is not recognising the correct native screen resolution (as specified in its user manual), you should download and install the latest device drivers for the PC's graphics card from the PC manufacturer's or the graphic's card manufacturer's website. You can use the free Belarc Advisor to identify all of a PC's hardware and software, including the make/model of the graphics card/chip.

Visit the Desktop PCs section of this site for information on how to buy, build, repair, fix, and protect the various types of desktop PCs.

Visit the Laptop/Notebook PCs section of this site for information on buying and protecting them, and fixing problems with them.

During normal operation, most LCD monitors use about 35W of electricity. This is approximately 70% less than the power used by a comparable CRT monitor, which consumes about 105W.

Power can be saved by enabling the power-saving option in the Windows Control Panel, which is called Power Options in Windows XP. This option switches the monitor into standby mode after a set time period. Moving the monitor or pressing a key restarts it.

In Windows Vista, the Power Options are under Hardware and Sound in the Control Panel.

Windows Vista saves energy with its new Power Plans and hybrid sleep mode -

http://articles.techrepublic.com.com/5100-10877-6129085.html

Some monitor's have more advanced power-saving features. For example, the 17" LCD Iiyama Prolite X436S has an infrared motion sensor on the top of the screen's bezel. It senses when the user is no longer in front of the monitor and makes the screen go blank and into standby mode. It switches back on as soon as the sensor detects motion in front of the monitor. It also has a light sensor that allows it to adjust the monitor's brightness according to the amount of light in the room. These features are not enabled by default on this model. The user has to access the Onscreen Display (OSD) controls and enable them manually. Reviewers have reported that that both of these features work very well.

HDMI/HDCP

Many LCD monitors now have extra video connections that allow them to be connected to a DVD player, games console or video camera (component, S-video, and composite video ports), and some LCD monitors now provide an HDMI high-definition port and support HDCP, which allows them to display the latest high-definition movies. Most HD TVs also have an HDMI/DVI port that allows them to be connected to a PC's graphics card that has an HDMI/DVI port.

Read the 720p and 1080p HDTV: The differences in these high-definition (HD) standards page on this site for more information on those two HD standards.

HDCP stands for High-bandwidth Digital Copy Protection, which is technology that allows the monitors that support it to authenticate themselves to high-definition video sources, such as a high-definition movie, thereby proving that they are an approved method of displaying the video rather than an illicit device that could be used to copy it. The movie studios have the option of restricting full high-definition playback to HDCP devices only. (A PC's video/graphics card can also be an HDCP device.) However, the movie studios are currently (July, 2007) not using that option, because most users don't have the HDCP-compliant hardware that supports it. However, to future-proof your purchase, you should buy an HDCP-compliant monitor. The digital copy protection is implemented digitally only, so if you buy a monitor that has a standard analog D-sub VGA graphics connector, you won't be able to watch HDCP-protected high-definition Blu-ray movies (Toshiba has lost the high-definition standards 'war' to Sony's Blu-ray standard and has stopped developing its alternative HD DVD standard).

HDCP was developed by Intel. It encrypts the signal between the HD video source (the high-definition Blu-ray or HD DVD player/drive) and the display/monitor. Digital output from a Sky HD box, Blu-ray, or HD DVD player will not be displayed if the DVI or HDMI input on the monitor isn't HDCP compatible. Windows Vista also has HDCP support as part of its digital-rights-management (DRM) software.

When the movie studios start marketing HDCP-protected movies, if you want to watch them through a Windows Vista computer, the PC's monitor and the video/graphics card will have to support HDCP.

HDTV For Gamers -

"Video games have always been on the cutting edge of visual technology, and the shift to high definition is no different. Gamers who opt to remain ahead of the pack want their HDTV, but tread carefully before plunking down the cash for a new set..."

http://www.tomshardware.co.uk/Gamers-Guide-HDTV,review-2384.html

Component, S-video and composite video ports

In addition to an HDMI port for playback of high-definition movies, the more expensive LCD monitors provide connections such as component, S-video, and composite video ports that allow the connection to the PC of devices such as DVD players, video camera, and games consoles (Xbox 360, Wii, PlayStation 3, etc.).

Visit the PC Gaming section of this site for more information on that subject.

USB/FireWire/HDMI/DVI/Ethernet/VGA cables

The following website provides a wide variety of the following cables - audio-visual, BT phone, power supply, drives, fans, HDMI, monitor, network, SCSI/SAS, USB, FireWire, printer, etc. -

Scan - http://www.scan.co.uk/

Display Properties: Setting screen resolutions, etc.

As in Windows XP, you can access Display Properties in Windows Vista by right-clicking with the mouse pointer on an empty space on the Windows Desktop and then selecting Properties in the menu that presents itself.

For Windows Vista, read Getting the best display on your monitor. The article covers CRT and LCD monitors.

For Windows XP, read Display Properties overview. It covers both the Home and Professional versions of Windows XP.

The following Q&A on this site deals with setting the screen resolution of an LCD monitor having upgraded from a standard CRT monitor: I have upgraded from a CRT monitor to an LCD monitor. How do I set the correct screen resolution for my LCD monitor?

1:1 pixel mapping

1:1 pixel mapping is technology used in some display devices, such as LCD monitors that matches the resolution set on a video/graphics card to the screen resolution so that each pixel of the video signal is mapped to the corresponding pixel on the LCD screen, producing the sharpest possible picture. The technique prevents a video display being stretched and distorted by the monitor.

If, for example, a PC's video card is set to a screen resolution of 1,280x720 and the LCD monitor is set to its native screen resolution of 1,280x800, without using 1:1 pixel mapping the monitor will show the reduced resolution on the whole screen - will scale it by stretching the image. However, if the monitor provides and is set to use 1:1 pixel mapping, the monitor will display the 1,280x720 screen resolution and show black boarders where the native screen resolution's pixels are not being used.

At the time of writing this (January 2009), not all LCD monitors support 1:1 pixel mapping. It is worth having in order to obtain the sharpest picture, so you should make sure that any LCD monitor you buy supports it.

Widescreen LCD desktop PC monitors and widescreen LCD laptop displays

Most new desktop and laptop/notebook PCs now come with widescreen LCD monitors/displays instead of the standard almost square monitors/displays that used to be the rule.

A widescreen has an aspect ratio (the ratio of its vertical and horizontal aspects) that allows widescreen movies to be displayed as they are on a widescreen TV. Visit the Monitors and Laptops pages on this site for more information on PC monitors and laptop PCs.

All About Aspect Ratios (And Why Widescreen Really Is Better) -

http://www.thedigitalbits.com/articles/anamorphic/aspectratios/widescreenorama.html

All of the older PC games designed for a screen that has a standard aspect ratio seem to be ruined when played on a widescreen. The characters appear short and fat, dials appear elliptical instead of round, and when online quite a few lines of the screen disappear so that scrolling is necessary.

A screen with a standard aspect ratio and a resolution of 1024x768 is the equivalent of a widescreen with a resolution of 1200x768, where 1024 and 1200 represent the width of the screen in pixels.

A widescreen display is just what someone wants in order to display a spreadsheet, because it can display more columns. It is also what is necessary to display widescreen television and DVD movies.

Most new PC games now support widescreen resolutions, which means that they'll display without any distortions. However, if a widescreen causes distortions in a game, you should look at the options for the display driver under Display in the Control Panel in Windows 98/Me/XP. If there is an option to disable video stretching, it adds black borders to each side of a widescreen that effectively reduces it to a screen with a standard aspect ratio.

In Windows Vista, Display Settings is in the Control Panel under Hardware and Sound. You open it and then open Personalization => Display Settings. The window that presents itself allows access to the following settings: Display Settings, Visual Appearance, Desktop Background, Screen Saver, Sound Effects, Mouse Pointers, and Theme.

As in Windows XP, you can access Display Properties in Windows Vista by right-clicking with the mouse pointer on an empty space on the Windows Desktop and then selecting Properties in the menu that presents itself.

The usual display icon in the Notification Area can be enabled to appear under Display Settings, but when you right-click on an empty area of the Desktop, you have to click Personalize in the menu the presents itself in order to bring up the window that contains the above-listed types of settings.

Visit the Laptop PCs section of this site for more information on them.

How to avoid monitor image persistence (screen burn, burn-in)

Note that a laptop computer's warranty does not allow its owner to claim for screen burn, because it is a natural property of the monitor.

Computer users who use programs that don't have set and fixed text menus and that use a white screen to display constantly changing text most of the time, probably won't have any problem with screen burn (burn-in) in a flat-panel LCD or an old-style CRT monitor.

However, both LCD and CRT monitors can suffer from burn-in (screen burn) when the computer to which they are attached run the same application that displays the same screen most of the time.

It is possible with an old-style CRT monitor to be able to see a text menu remaining on the screen even when the monitor itself is switched off. That can't happen with an LCD screen, but a previous image can become stuck and be viewed when the monitor is switched on.

With CRT monitors, if an image or menu is displayed in the same place on the screen for a long time, the same kind of bombardment by the cathode rays in that area can burn the screen phosphor so that it remains showing that display forever.

With LCD flat-panel screens , the same problem can be as bad or worse. This is because, with a liquid-crystal display, the crystals change their state when a voltage is applied to them, and, if left in the same state for too long, they can become stuck in that state. LCD-monitor manufacturers call that property "image persistence". Fortunately, unlike screen burn in CRT monitors, image persistence in LCD screens can almost always be reversed by displaying a white screen or by reversing the colours in the image that caused the problem (by displaying a colour negative of the image, etc.).

The following article on the subject suggests preventative methods, such as using a screensaver or using appropriate power-saving settings under the Windows Power Options in the Control Panel (in Windows XP and Windows Vista using its Classic View option).

LCD Image Persistence -

http://compreviews.about.com/od/monitors/a/LCDBurnIn.htm

In Both Windows Vista and Windows XP, you set a screensaver to work by right-clicking and empty space on the Windows Desktop. Next, click on Properties on the menu that comes up, and then open the Screen Saver tab in the Display Properties window.

If you have set a logon password in Windows XP Home Edition, you can use a key combination to bring up the logon screen so that it works in the same way as a screensaver. No one can use the computer until the password is entered, and when it is entered, you resume immediately from where you left off. To bring up the logon screen, just press one of the two Windows keys (they have a Windows flag on them) and the L key. This also works in Windows XP Professional Edition, but there is no need to set a password, because it requires the user to set a password during its installation.

You can almost certainly also do that in all of the different versions of Windows Vista.

A CRT monitor used to be more more suitable than an LCD screen for the playing of rapid-motion graphics, such as are displayed in PC games and video. This was because the LCD technology was not as fast at refreshing the screen, and therefore gave rise to motion blur (blurring of the images during rapid-motion graphics). However, this is no longer the case.

Strictly speaking, the refresh rate for an LCD monitor is called its pixel response time, because LCD technology doesn't refresh the screen in the same way as with a CRT monitor, but for the sake of convenience, I'll just call the process the refresh rate for both types of monitor. This is usually between 20 and 50 milliseconds. It is measured in milliseconds not Hz, as with CRT monitors. The lower the pixel response time, the faster the pixels refresh (turn off and on), making the screen update faster - an important factor for PC gamers.

When an LCD screen displays images that show rapid movement, a blurring effect called ghosting will be evident. How much ghosting there is depends on the quality of the monitor. However, the technology has improved to the point now that ghosting has been eliminated on LCD displays of quality.

The screen resolution is determined by the number of pixels in use by the viewable area of the screen. The pixels are the small dots that give colour to the screen. If the screen resolution is 800X600 pixels (480,000) for a 15" CRT monitor, the screen has a width of 800 pixels and a height of 600 pixels. But if the same screen size has the screen resolution set to 1024X768, nearly double the number of pixels (786,432) are employed to create the image.

For CRT monitors, remember that monitors set to run at high resolutions make the images on the screen appear smaller on the same monitor that is set at lower resolutions, because the same information is displayed at the higher resolution but in less space. That is why it's common to see web pages shrink when the screen resolution is increased. The HTML code of such pages is set to cover a set number of pixels. By increasing the resolution there are more pixels per square inch, so the information on the page shrinks. If the HTML coding is changed to make the contents spread over the entire width of the screen instead of across a set number of pixels, then the page fills the whole screen again at the higher resolution.

Moreover, remember that with a CRT monitor the higher the screen resolution the lower the maximum refresh rate, because there are more pixels to refresh. For the resolution you'll use most, you'll want to run a refresh rate of at least 70Hz to avoid flicker, which causes the eyes to tire. 85Hz is probably the ideal resolution.

An LCD monitor works best using its native' resolution, and not so well set to its other supported resolutions, because these aren't actual, they're emulated resolutions. This is not the case with CRT monitors, which work equally well with all of the many resolutions that they support.

Looking at an LCD screen set to less than its native resolution can be as tiring on the eyes as looking at a CRT monitor set to use a low refresh rate. Using a lower resolution on an LCD screen cannot harm the monitor because it is still using its native resolution to emulate lower resolutions that display less information on the screen, which, in effect, makes it look as if you have zoomed in on what was being displayed on the screen at the native resolution.

If you want to increase the size of the font being used to display text on the screen, right-click with the mouse on an empty space on the Windows Desktop, and click on Properties in the menu that presents itself. Click on the Settings tab of the Display Properties window that comes up. The native resolution is usually the highest resolution, so, if the slide bar under Screen resolutions is not set to the maximum, use your mouse to move it as far as it will go towards More.

Next, click on the Advanced button. You can change the DPI setting on the General tab, which is set to 96dpi by default. On the drop-down menu, there is a setting for 120dpi, or you can create a custom setting. DPI stands for dots per inch. Increasing the DPI makes the font being used appear larger onscreen.

Note that some programs, such as Microsoft's Outlook, which is used for e-mail, etc., ignore the Windows setting for font size, so you have to set the font size that such programs use from within them.

Lower resolutions, and in some cases higher resolutions than the 'native' resolution, can be set on an LCD display, but the image will probably appear blurry. Some LCD monitors are better than others at handling non-native resolutions. The 'native' resolution and how to set it should be disclosed in the monitor's or the computer's user manual. If you need to change your monitor's resolution frequently, you're probably better off with a CRT monitor.

With LCD monitors, the pixels don't have the pulsing or 'decaying' nature of the phosphors of the pixels of a CRT monitor that are responsible for its flickering. Thus LCD monitors can operate at lower comparative refresh rates than CRT monitors without showing any flickering.

When considering LCD monitors in order to make a purchase, pay close attention to what happens when you view the screen from various angles. The best monitors allow you to sit further to the sides instead of just directly in front of the screen without the brightness dimming or the colours shifting in any way.

Television pictures and DVD movies often don't appear at their best on an LCD monitor, because the images are displayed with such sharpness that any natural or unnatural defects in the footage or the interlacing used by television broadcasts will become noticeable immediately.

Interlacing, which skips refreshing alternate lines of the screen, can create jagged edges that are more noticeable on LCD screens. Moreover, LCD screens often have to be viewed from directly in front of the screen to avoid a deterioration in the picture quality, but this is not the case with CRT monitors. Therefore, if a user's PC has an LCD monitor, he or she will benefit from watching television and DVD movies via a large- screen TV set. To connect the PC to a television set requires the use of an S-video or composite connection and cable.

Microsoft's Windows XP Media Center Edition uses Microsoft's Media Center to integrate television into Windows. It's also able to control a Sky Digibox via a PC.

The Media Center Edition does not exist as a separate operating system with Windows Vista. The Media Center Edition is now included in Vista Home Premium and Vista Ultimate Editions, which also provide advanced integrated search and the ability to burn and author DVDs.

The size of the screen in inches measures its diagonal length from the top corner to the bottom corner on the opposite side of the screen. Standard displays have a 4:3 aspect ratio of height to width that makes them look almost square. Widescreen displays that are described as that in their sales specifications have a 16:9 aspect ratio of height to width that makes them rectangular. Almost all of the new LCD monitors sold now are widescreen, and all of the current laptop/notebook PC screens are widescreen. Obviously no one would want to buy a square monitor if widescreen alternatives are available, so the square monitors are no longer being made. However, the square monitors will be available on the second-hand market for several years to come.

Because some of the screen is not visible (is hidden by the casing) on a CRT monitor, a 15" LCD monitor is the equivalent of a 17" CRT monitor, and a 17" LCD monitor is the equivalent of a 19" CRT monitor, etc. With most CRT monitors an inch or more of the screen is hidden by the case. So, a typical 15" CRT monitor will only have a visible diagonal screen measurement of 14", etc. But all of the screen of an LCD monitor is visible.

If you have your computer on all the time, or run a network, you should know that LCD monitors use significantly less power than CRT monitors, and they can be far more easily recycled than their bulkier forerunners. An LCD monitor can use as much as 40W less power than its CRT equivalent. So, running an CRT monitor instead of an equivalent LCD monitor would be like having an 40W light on all the time it's being used.

The 'native' screen/display resolution of most 15" LCD monitors is 1024X768 (or 1024 by 768 pixels), and for both 17" and 19" monitors of good quality it is 1280X1024. This means that the screen has a horizontal length of 1280 pixels and a vertical length of 1024 pixels. For a 21" screen the native screen resolution is 1600X1200.

A poor quality 17" display could have the same 'native' resolution (1024X768) as a 15" display. (There is an explanation of the differences between screen resolutions and screen refresh rates further down this article.) If you require the higher resolution of 1280X1024 from an LCD monitor, you would need a 17" display area, because you can only have so many pixels of a certain size in a given display area. To pack more pixels into a given screen area requires smaller pixels, so when the pixel size reaches the minimum size possible with current technology, you have to increase the display area to achieve a higher screen resolution.

Note that the higher the 'native' resolution of an LCD monitor, the more expensive it is.

Display resolution - http://en.wikipedia.org/wiki/Display_resolution

The safest way to upgrade RAM: Use the UK and US Crucial Memory Advisors

Paul Mullen, the highly-respected computer guru of the Helpfile at ComputerShopper.co.uk - "I have recently been buying my memory only from Crucial Technology. I would rather pay the extra cost than waste time trying to track down the obscure program faults that bad memory can cause."

The memory requirements of the versions of Windows Vista

Most of the versions of Windows Vista require more RAM memory to run optimally on a computer that doesn't use memory-hungry applications than Windows XP. A video-editing application is an example of memory-intensive software. Only Windows Vista Home Basic has a recommended minimum amount of memory of 512MB, which is the same amount recommended for Windows XP. Windows Vista Home Premium, the most popular version, and Windows Vista Ultimate require a recommended minimum of 1GB (1024MB) of memory, which is twice the amount of minimum memory recommended to run Windows XP. For more information on computer memory, read the RAM pages of this site.

For example, if your computer has an Asus motherboard, open the menu, scroll down to ASUS, and click GO. If, say, you have a Dell computer, scroll down to DELL, and do likewise. You will be taken to the relevant information on Crucial's website.

If you don't know the make and model of the motherboard installed in your computer, here is a good free utility - Belarc Advisor - that creates an analysis of the hardware and software on a personal computer. Look under FREE DOWNLOAD - http://www.belarc.com/. Another utility that also provides detailed information on the memory itself is CPU-Z.

Colour/Color Management: How to calibrate an LCD or CRT monitor

Windows Vista has built-in colour calibration, but Windows XP needs to be updated by downloading the Color Control Applet.

Better color management for Windows XP -

"New Microsoft Color Control Panel Applet for Windows XP helps you manage Windows color settings in one place." - http://tinyurl.com/ajg7t

This page provides links to articles on colour management in Windows Vista:

Windows Image Color Management -

http://www.microsoft.com/windowsxp/using/digitalphotography/...

If you are serious about calibrating your monitor, you can use software such as Spyder2express which was priced at £60 in May 2008. It does not depend on any subjective calibration choices made by the user.

ColorVision Spyder2express -

"The latest addition to the Spyder2 family, the Spyder2express replaces the award-winning ColorPlus. Providing quick and accurate monitor calibration, it gives you precise and realistic on-screen colour, true-to-life flesh tones plus flawless shadow detail and highlights in just three steps. The Spyder2 and its advanced algorithms work behind the scenes to give you the best colour experience possible." -

http://www.pcwb.com/catalogue/item/COLSPY03

3D PC gaming monitors

First Look: Zalman 3D Monitors -

"Most PC games are set in three dimensional virtual worlds. Unfortunately these 3D environments must then be reduced to a 2D image for display on a PC monitor. So we were excited to see Zalman's new range of monitors, which are capable of tricking your brain into seeing the 3D information inherent in games..." -

http://www.pcpro.co.uk/shopper/news/141099/first-look-zalman-3d-monitors.html

Hands on with Zalman’s 3D gaming screen -

http://www.pcadvisor.co.uk/blogs/index.cfm?entryid=1432&blogid=18

Glossy screens

A glossy screen is one that has a special coating that makes it look glossy.

The pros and cons of having a glossy screen are as follows. Glossy screens improve the contrast, which makes them ideal for viewing videos, photos, and playing PC games. However, the glossy coating is very reflective, which makes it difficult to view under bright fluorescent lighting and in sunlight.

If you use a notebook in an office or outdoors, a standard screen or one with an anti-glare coating is the best choice. The screens don't produce the high quality picture that a glossy screen does, but they don't reflect much light.

LCD monitor screen protectors

LCD screens are far easier to damage than CRT screens that are protected by covering of a glass. Even when you clean an LCD screen you should not apply pressure to its surface. The pixels that make up the screen can easily be crushed by poking or the surface of the screen can be cut by sharp objects, such as pens, or scratched by using paper towels to remove dirt.

If you want to protect an LCD screen, including the LCD screen of a laptop computer, you can purchase a screen protector. The prices vary from £25/$50 to £50/$100.

To find examples and vendors, you can enter a search term, such as lcd + screen + protector, as is, in the Google search box at the top of this page, with its Web radio button enabled.

Here is a page I found:

LCD Screen Protector - http://www.ergoindemand.com/lcd-screen-protection-filters.htm

Several sizes of the screen protectors offered on that page can be used with laptop computers.

You can also make your own screen protector. 1/8" thick clear Lucite Acrylic Plastic, which is easy to attach to the monitor with a few little pieces of duct tape, provides all the protection you need. You should be able to buy some from a DIY or hardware store. If you want a neater solution than duct tape provides, you can use something like Velcoin Brand Fasteners. You can find local vendors by entering velcoin + brand + fasteners, as is, in the Google search box at the top of this page, with its Web radio button enabled.

The analog (VGA) and digital (DVI) connections between monitor and video card

As with CRT monitors, both analog and digital LCD monitors are available.

The English English spelling of analog is analogue, but I always use the US spellings of technological terms.

Analog is outgoing monitor technology, and digital is the incoming monitor technology. Until an outgoing technology is replaced by the incoming technology completely, the two technologies overlap. Therefore, you can purchase LCD monitors that have only an analog connection port or both analog and digital connection ports.

There is more information on this subject further down this page.

Because all devices within a computer are digital, including the video card, using a standard analog VGA monitor with a computer requires a digital-to-analog converter (DAC) built into the video card that converts its digital signal into an analog signal that the analog monitor supports.

Some LCD and CRT digital monitors have both standard D-sub VGA ports and digital DVI ports, but others have one or the other only.

The top image above shows an ATI Radeon graphics card that has a standard analog D-sub VGA port (left, small, blue), which is older technology, and a purely digital DVI-D port, which is the current digital technology. The image below it shows a close-up view of the ports panel of another graphics card. It has a standard analog D-sub VGA port and a DVI-I port, currently the most common type, which can produce both analog VGA and digital DVI signals. It has four pin holes to the left of the main body pin holes (three rows of eight) that carry the VGA signal. If you have a PC monitor that only has an analog VGA connector, you can connect the graphics card and the monitor by using a cheap DVI-to-VGA cable that is often provided with a graphics card. The cable simply connects the four pins carrying the VGA signal to a D-sub VGA connector on the monitor.

However, a DVI-D port on a graphics card (or integrated motherboard) is purely digital. If you want to connect one to a VGA monitor, you would have to use a digital-to-analog converter/adapter, which is an actual device that costs around £200 or more. You would have to choose between buying a new digital monitor or an expensive adapter.

Below are the magnified images of a standard analog D-sub VGA connector of a VGA port (left) and a DVI-D port (right). As you can see, the four pin holes required to carry a VGA signal are not present.

Most current high-end graphics cards have two DVI ports (no D-sub VGA port), which could be two DVI-D ports, or one DVI-D port and one DVI-I port. You can connect the card to two monitors that can then display different applications.

The image below shows an example of a graphics card with two DVI ports, which could be a DVI-D port and a DVI-I port, two DVI-D ports, or two DVI-I ports.

The dual-link DVI interface and cable

Some LCD PC monitors, such as the 30" Hazro HZ30WS, has a native screen resolution of 2,560x1,600 that exceeds the capabilities of single-link DVI, which can manage screen resolutions up to 1,920x1,200. Most video/graphics cards can manage higher resolutions, such as 2,560x1,600, but a dual-link DVI cable has to be used instead of the single-link version.

A dual-link cable has a full complement of 24 pins in a 3x8 configuration. A single-link cable has two 9-pin blocks that omits the six pins in the centre of the connector.

The following illustrated article shows the pin-outs of both connectors.

Digital Visual Interface - http://en.wikipedia.org/wiki/Digital_Visual_Interface

The High-Definition Multimedia Interface (HDMI) connection

High-Definition Multimedia Interface (HDMI) is a new type of connector for a high-definition display that can carry sound as well as a digital picture. It is backwards-compatible with the DVI interface if a converter cable is used.

High-Definition Multimedia Interface - http://en.wikipedia.org/wiki/HDMI

The new DisplayPort graphics standard

The DisplayPort graphics standard is being promoted as the successor to the DVI graphics standard. The bandwidth of the dual-link DVI standard (that uses a special dual-link cable) can barely handle screen resolutions of 2560x1600 pixels for large widescreen displays; using higher resolutions requires a reduction of the refresh rate. The HDMI standard has similar limitations, but this is not a problem yet because HD TVs are unlikely to go beyond using a resolution of 1920x1080 pixels for several years to come. The current DisplayPort 1.1 standard has similar limitations to dual-link DVI, but greater bandwidth is expected in 2008, going up to resolutions of 3840x2400 pixels. DisplayPort graphics cards drive LCD screens directly, so don't have to make use of the current electronics, which should make the displays slimmer and cheaper. It remains to be seen if the standard succeeds in replacing the DVI and HDMI graphics standards.

DisplayPort - FAQ - http://www.displayport.org/FAQ/default.htm

LCD monitors: Viewing angles

LCD monitors create an image by having electric current running through the pixels that make up the surface of the screen. Different currents turn on particular shades of colour. The colours that make up an image are best viewed from straight in front of the monitor. The colours become distorted or washed out the further away the viewer is from being directly in front to the screen. Therefore, the specifications of LCD monitors include the horizontal and vertical viewing angles. A horizontal and vertical viewing angle of 180 degrees (180°) would mean that the image is fully visible to a viewer who is looking horizontally from side-on to the screen and looking down vertically from the top of the screen. 160°/160° means that the screen can be viewed horizontally and vertically from angles of 160° to the screen without distortion of the image.

This specification is important if the screen is required to be seen by users who are not sitting directly in front of the screen. If only one person needs to see the screen, it is of no importance.

A common recommendation is a viewing angle of at least 140° horizontal and 120° vertical (140°/120°). The viewing angles become more important as the screen size increases, because the larger the screen the more technically difficult it is to have high viewing angles. You should take a monitor manufacturer's specifications in this regard with a pinch of salt. Therefore, if the viewing angles of an LCD monitor are of importance to you, you should find a vendor that allows you to see them them for yourself before you buy it.

The screen of a CRT monitor can be viewed almost from side-on without much distortion, but an LCD monitor has a smaller viewing angle in which to view a similar quality of image. However, more technically advanced LCD monitors that are becoming available have wider viewing angles, so the difference in viewing angles between the two types of monitor (CRT and LCD) is not as marked as was the case.

LCD monitors: Screen elevation

The screen elevation is the distance from the desk's surface to the bottom of the monitor's panel. An LCD monitor that is incorrectly positioned can be the cause of neck and shoulder pain.

Ideally, the top of the screen's panel should be on the same level as the top of your head, making the eye level about two to three inches lower than the top of the panel.

If the screen is fixed to its stand, to raise it to its correct height could require the use of an additional monitor stand.

If the monitor is 19" or less, it should be an arm's length away when you are seated directly in front of it. The distance should be increased a little if the monitor is 20" or larger.

LCD monitors: Brightness

The level of brightness is not much of a problem with CRT monitors. However, LCD monitors are backlit (lit from the back of the screen from a single source of light) and therefore the screen shows different levels of brightness, because the strength of the back light is not exactly the same over the whole area of the screen. For example, if the source of the back light is located at the bottom of the monitor, the top of the screen might appear less bright than the bottom of the screen. With most LCD monitors, any difference is hardly noticeable.

The measure used for the brightness rating of an LCD monitor is often called 'nits', and is commonly in the range of 70 to 300 nits. The higher the number, the higher the maximum brightness level of the screen.

Brightness or luminance, can also be expressed as candelas per square metre (250 cd/m2, 300 cd/m2, etc.). As a specification, the brightness of the screen of an LCD monitor can be as important as its contrast ratio. However, note well that the manufacturers' specifications for brightness have proved to be as unreliable as the contrast ratios that they specify, because the figures depend on how the monitor has been tested, and there is no standard set of tests that is applicable to all of the LCD monitor manufacturers.

Some monitors have a high maximum level of brightness that cannot be reduced enough to be comfortable for some users, or a low maximum level of brightness that is too low for some users. For that reason, it is always best to test a PC's monitor or an individual monitor before it is purchased.

LCD monitors: Refresh rates

The pixels in a standard colour LCD screen are activated directly by signals from the video card. That is to say that they are not activated serially by electron guns, as is the case with a CRT monitor. Moreover, they do not fade out if they are not reactivated regularly. Each pixel has its own connection to the video card. The pixels are turned on by signals from the video card, and stay on until other signals arrive which make them turn off or change their state. Because if this, many LCD's can have a default refresh rate set as low as 60Hz yet still do not appear to flicker. (A CRT monitor set to use a low refresh rate of 60Hz would flicker noticeably.)

However, this means that whatever image is on screen is not being updated as often as it would be if a higher refresh rate, of say 75Hz, was being used. The image on the screen may appear flicker-free, but when displaying video and other rapid-motion images, you may see smearing, blurring, and loss of detail in the moving areas of the screen.

If you cannot spend time using it, you should read the reviews of an LCD monitor before you purchase it. If you can get to use it, don't just view the content provided by the vendor, because it is designed to show the monitor at its best. If possible, try playing the sort of games that tax the screen as much as possible.

As with a CRT monitor, in order not to tax an LCD monitor too much, you should use the lowest refresh rate that provides acceptable viewing no matter what is being displayed.

There is more information on refresh rates further down this article.

LCD monitors: The contrast ratio

One of the control features of most LCD monitors is called the contrast ratio. Depending on the range supported, you will see it listed as 350:1, 400:1, 500:1, and 600:1, etc.

The contrast ratio represents the relative difference in contrast between the purest white and the darkest black that the monitor is capable of displaying for that particular contrast ratio setting.

Most brand-name LCD monitors have contrast ratios in the 350:1 - 700:1 range. You can buy LCD monitors with a contrast ratio of 1000:1. An example is the 21" Samsung 215TW monitor. Other screen technologies such as plasma monitors also offer contrast ratios of up to 1000:1.

The LG Flatron L226WTQ widescreen LCD monitor is advertised as having a 5000:1 contrast ratio, which LG says is a UK first. However, this is a digital fine contrast (DFC) ratio. It is produced by software that analyses the image and then optimises the backlight and colour luminance to achieve this high contrast ratio. DFC is only swiched on when the monitor is in the preset movie mode.

It is said by the manufacturers of LCDs that the higher the cotrast ratio is the better, because whites and blacks should be as well contrasted as possible. But this claim is being disputed by several reviewers.

LCD Specs: Useless? Tested contrast ratios rarely conform to vendors' specs - a very informative four-page article well worth reading:

http://www.pcworld.com/article/id,110483-page,4/article.html

Dynamic contrast ratios

Dynamic contrast ratios monitor the grey levels and adjust the screen's backlight to reflect light and dark shades more accurately than a standard blanket contrast ratio. The backlight power is lowered for dark scenes, thereby creating darker shades, and the backlight power is increased for lighter scenes, thereby creating lighter shades.

Old-style LCD monitors use a cold cathode fluorescent (CCFL) lamp backlight that affects the entire screen when the backlight is dimmed or lit up. New-style LCD monitors use light-emitting diode (LED) backlights, which make it possible for individual parts of the screen to be adjusted for contrast independently, thereby improving contrast control by making it dynamic instead of static.

Colour (US: color) temperatures

Some LCD monitors provide settings for colour temperatures. Common options are 9300K, 7500K, 6500K, and 5000K. The color temperature of a screen is usually set to 9300K at the factory for most computer monitors and televisions. This corresponds reasonably well to the colour of "Bright White" paper under office lighting. Many monitors have user settings for other values, such as 5000K and 6500K, which are useful for graphic arts and photography respectively.

A relatively low colour temperature, such as 6500K, makes the colours warmer and more yellow. A high colour temperature, such as 9300K, makes the colours cooler and more blue. A setting of 6500K to 7500K makes the colours look like an overcast sky. A 9300K setting corresponds to a clear blue sky and is usually used when high colour contrast is required. You should set the monitor to make use of the option that suits your taste best.

Some more detailed information on LCD monitors

The screen resolution and aspect ratio

TFT stands for Thin Film Transistor (it was formerly called active matrix) and it is the current name for the standard that determines how an image is displayed on virtually all current flat panel and laptop monitors.

The screen resolution and the aspect ratio are the other main technical specifications involved in LCD monitors. The resolution is the number of pixels activated or displayed on the screen, and the aspect ratio is the relationship between the height and width of the screen.

The current resolution standards include XGA, SXGA, SXGA+, UXGA, and QXGA. When a W appears in front of any of these standards, such as WXGA, it refers to a wider version of the original standard.

The standard on entry-level laptops is XGA, which stands for eXtended Graphics Array, and it has a rated resolution of 1,024 horizontal pixels by 768 vertical pixels (1024X768).

SXGA or SuperXGA is a display that supports a resolution of 1280 horizontal pixels by 1024 vertical pixels (1280X1024).

SXGA+ supports a resolution of 1400 horizontal pixels by 1050 vertical pixels (1400X1050).

UXGA supports a resolution of 1600 horizontal pixels by 1200 vertical pixels (1600X1200).

QXGA supports a resolution of 2048 horizontal pixels by 1536 vertical pixels (2048X1536).

WXGA - Widescreen Extended Graphics Array - 1280×720 (922k) 1280×800 (1024k)- aspect ratio 16:9 - 1440×900 (1296k) - aspect ratio 16:10.

The following page provides more information on these standards and many others:

Computer display standard -

http://en.wikipedia.org/wiki/Computer_display_standard

Remember that every LCD monitor has a native resolution, which is its optimal resolution setting. It is set under Conrol Panel => Display => Settings, under Screen area. If you don't have a user manual that came with the computer or monitor that provides it, you can find out what the native resolution is by setting resolutions until you obtain the best quality of picture.

The higher the native resolution that an LCD monitor has the better, generally speaking, but there is one major issue with very high resolution displays: the larger the resolution, the smaller the information (text and images) appears on the screen, because the same information is packed into a smaller space. The lower the resolution, the more space the information on the screen needs to occupy, and the larger it appears. If you use a resolution that is lower than that which allows all of the information to be displayed on the screen at once, a scroll bar appears at the bottom of the screen and you have to scroll to reveal the hidden information.

The people who have a problem reading small text on the computer screen may actually have a more difficulty reading it if they purchase a very high resolution display. And there's no point in having or buying an expensive, very high resolution display only to run it at a much lower, more comfortable resolution.

Remember that the higher the native resolution that an LCD monitor supports, the more expensive it is.

The standard aspect ratios (the relationship between the height and width of the screen) are 4:3 (traditional almost square displays) and 16:9 (newer widescreen displays). A resolution standard for an LCD monitor that starts with W is going to be a wider screen than a traditional screen, displaying up to 30% more information.

Aspect ratio (image) - http://en.wikipedia.org/wiki/Aspect_ratio_(image)

Wider screens benefit the people who work on large spreadsheets, because more cells are displayed, and therefore less scrolling is involved. Particularly large graphics can be displayed in their entirety. For standard word-processing, the benefit of having an extra-wide screen is that it can show two or more legible pages on the screen, side by side.

Read the Q&A on aspect ratios on the Video and Graphics Problems pages on this site called: Why do some PC games look stretched on my widescreen LCD monitor?

LCD TVs with a cinema 21:9 aspect ratio

Note that if you have plenty of money to spend on a LCD TV screen that shows movies in the same aspect ratio as they are shown in cinemas, ultra-widescreen TVs are available that have a 21:9 aspect ratio. Watching movies on such a screen shows no black bands at the top and bottom of the screen, but the experience of watching TV programs can vary depending on the original aspect ratio in which the programmes were recorded - 16:9 or 4:3. The 16:9 programmes can be stretched by software built into the TV to cover most of the screen, but there are black bands on each side of programmes recorded for a squarish 4:3 aspect ratio.

Philips’ 21:9 aspect ratio TV on video -

http://www.crunchgear.com/2009/01/29/philips-219-aspect-ratio-tv-on-video/

There are other, more technical specifications such as the contrast ratio (more about that further down the page), the megapixel rating (much like that used for digital cameras), and the viewing angle that are a little more difficult to describe and grasp.

As a home computer user, there's not much point getting too caught up in those specifications. Before buying a computer with an LCD monitor or just an LCD monitor, you should visit a computer store that allows you to try using several monitors in order to get a feel for the differences between them and which of them you find most comfortable to use.

Remember that you will be spending many hours in front of the monitor, so the more it suits your eyesight the better. Just be careful not to overbuy when it comes to the resolution and the aspect ratio.

How to choose an LCD monitor

While on the subject of LCD monitors, now is a good time to provide some information on how to go about choosing one from the many makes that are available, because most of the rest of article is devoted to information about CRT monitors.

Note that the terms screen resolution, refresh rate, and dot pitch, as applied to CRT monitors, are discussed on Page 2 of this article.

The dot pitch pixel size in LCD monitors is called the pixel pitch.

The specifications you should look for in an LCD monitor depend on the monitor's display size (the diagonal distance between two corners, usually measured in inches).

New 15" LCD monitors are no longer available, but can still be purchased second-hand. If, for some reason, you're looking to buy a 15" LCD display, then you want to make sure the screen can display a native resolution of 1024X768. Most of the time you won't be able to find a 15" LCD display that can display a native resolution higher than 1024X768, but you definitely don't want its maximum resolution to be lower than this.

Remember that a 17" LCD monitor can display much more information on the screen. A screen resolution of 1240X1024, which is the native resolution of most 17" LCD displays, can show two MS Word documents or web pages side by side, and can view large spreadsheets without having to scroll to the information. Doing that is not possible on a 15" LCD monitor with a native screen resolution of 1024X768.

The larger the screen size, in order to maintain the same picture quality, the higher the maximum supported resolution has to be. 17" and 19" LCD monitors currently have the same native resolution of 1280X1024. This means that the smaller screen area of a 17" monitor contains the same amount of pixels as the larger screen area of a 19" monitor. Therefore, the picture quality of the 19" monitor has to be inferior to a 17" monitor made by the same manufacturer. But note that the picture quality of the same size of screen varies between manufacturers, and even between different models made by the same manufacturer.

20" LCD monitors have a native screen resolution of 1600x1200 pixels. They are useful for users who want to edit large digital photos, documents, or spreadsheets, and run two applications side-by-side.

For mainly entertainment purposes, a widescreen LCD monitor is the best choice. They can be used to watch widescreen movies and to edit two documents side-by-side.

There is more information on the native resolution of an LCD/TFT monitor further down this page.

Note well that some LCD monitors have a non-detachable monitor cable that is connected to the computer's video card. If you see the phrase "captive D-sub" in the specifications of the monitor, it is referring to this. In other words, the cable is part of the monitor, and, as such, can't be replaced easily if it is damaged. The monitor's manufacturer will probably be able to fit a new cable, but it's likely to be expensive repair job. Most LCD monitors come with a detachable D-sub VGA or DVI cable, or both types of cable. All you have to do is buy a new one should it be rendered unusable.

If you're stuck for choice between a few LCD displays, then compare the pixel pitch sizes. The pixel pitch tells you how sharp the screen will be. The lower the number, the smaller the distance between the pixels, and the sharper the images produced will be. CRT and LCD monitors with the lowest dot pitch/pixel pitch sizes are the most expensive because of the extra expense involved in the manufacturing process. Extra miniaturisation is always more costly.

While the vertical refresh rate measured in Hz (Hertz) is a useful gauge of performance on a standard CRT monitor, you have to know what the pixel response time is for an LCD monitor. This is usually varies from between 25 and 12 milliseconds (ms). The lower the pixel response time, the faster the pixels refresh (turn off and on), making the screen update faster - an important factor for gamers.

By the middle of 2006, the pixel response time was down to as low as 2ms.

Looking at the technical specifications of LCD monitors, you might ask why some LCD are described as having a contrast ratio of, say, 400:1?

Well, the contrast ratio needs to to be as high as possible. It is rare, but LCD monitors can be found with a contrast ratio of 1000:1. As usual, the higher that the contrast ratio (or any of the other specifications) are, the more expensive the monitor tends to be.

Now, all you have left to consider in your search for an LCD monitor are the extra features.

Some LCD monitors support digital video, auxiliary composite input, and even have built-in TV tuners or speakers. The choice is yours if you want to pay more for a monitor that provides them. If you don't require any of these features, now or in the future, you could pay less for a monitor that doesn't provide them.

Entering a search phrase such as "lcd monitors", or "recommended lcd monitors", lcd + monitors, etc., in the Google search box at the top of this page (with its Web radio button enabled) should provide you with enough links to a wide enough range of information to be able to compare the technical specifications and prices of many different LCD monitors.

Here is a review site I found. Top-ten products - PC World Top-ten-rated hardware - PCs (desktop and notebook), video cards, monitors (CRT and LCD), hard disk drives, CD-RW and DVD drives, printers (inkjets and black/colour lasers), scanners, digital cameras, camcorders, audio players, and product reviews. -

http://www.pcworld.com/reviews/hardware/

Dead pixels

Also note that you are far more likely to have dead pixels in an LCD monitor than you are with a CRT monitor. Very few manufacturers guarantee that desktop or notebook LCD panels will be perfect. Some pixels on a brand-new LCD screen could be dead, and show as black spots, or can be stuck on one colour (red, blue, or green), or even be stuck on one level of brightness, and so appear brighter or dimmer than the surrounding pixels.

Most LCD monitor manufacturers have a policy on the percentage of dead pixels that are allowed to get through their quality control procedures. More dead pixels are usually considered acceptable around the edges of the screen than in its centre.

You are advised to find out what the manufacturer of an LCD monitor's policy is concerning dead pixels before you make a purchase. The manufacturer will refuse to repair or replace an LCD monitor if the number of dead pixels doesn't comply with its policy concerning them. The problem is that the dead-pixel policy is usually not published, so you might have to go to some trouble to find out what it is.

Most of the major LCD monitor manufacturers adhere to the Class II section of the ISO 13406-2 standard that sets a policy on dead pixels. Under this standard, before an LCD monitor can be classified as being faulty, it has to suffer from one of the following faults:

1. - Two unlit pixels

2. - Two always lit (white) pixels

3. - Five red/green/blue pixels

4. - Two red/green/blue pixels in close proximity.

However, note that different manufacturers can interpret the ISO standard in different ways. For instance, one manufacturer might replace an LCD monitor if the two unlit pixels are at the edge of the screen, but another manufacturer's policy on dead pixels might not regard that as a fault that warrants a replacement.

Visit http://www.iso.ch/ for more information on that ISO standard.

If a pixel is stuck on one colour, there are ways in which it might be unstuck.

How to Fix a Stuck Pixel on an LCD Monitor -

http://www.wikihow.com/Fix-a-Stuck-Pixel-on-an-LCD-Monitor

Monitor drivers (.inf files)

If you're looking for a driver for a particular monitor because your version of Windows uses its standard Plug and Play Monitor driver (because it doesn't have the correct one in its driver library to make it show up correctly in the Device Manager), try looking for it on this site:

http://www.monitor-drivers.com/

See the next item for information on how to install the correct monitor in the Device Manager.

Changing the monitor in the Device Manager

Windows might install its standard monitor .inf file (a file that has an .inf extension such as monitor.inf), which configures the monitor for the Device Manager, or it might install the wrong one, or an updated file might become available that isn't on the Windows CD. If any of these circumstances is the case, just follow these instructions to put matters right:

1. - If it can't be installed from the Windows CD, download and uncompress your monitor's .inf file from its manufacturer's home page, or from a drivers' site such as the one provided in the previous item.

2. - In Windows XP click Start => Control Panel. Double-click System. Click the Hardware tab => Device Manager. Double-click Monitors. Right-click the monitor that is listed there. Click Properties => the Driver tab => Update Driver => Next => Install From A List Of Specific Location. Click Next. Click Don't Search I Will Choose The Driver To Install. Click Next. Click Have Disk. Click Browse and use the feature find and select the monitor's .inf file. Click Open to install it.

In Windows Vista, the Device Manager can be accessed in several ways, such as by typing devmgmt.msc in the Start => Start Search box, or under Hardware and Sound in the Control Panel.

The procedure is almost the same in Windows 95/98/Me systems. To open the Device Manager, right-click on My Computer, click Properties, and click the Device Manager's tab to open it.

Use Windows Explorer to open the Windows\INF folder to have a look at the .inf files that are available to Windows.

How to clean an LCD TFT monitor

Care should be taken in cleaning an LCD monitor, because the screen isn't as rugged as the screen of a CRT monitor. Here are some instructions taken from a user manual probably written in China:

1. - Be gentle to clean the screen.

2. - Never ever using any kind of corrosiveness chemical dissolvent to clean the screen.

3. - We suggest that using a clean camel hair brush or a soft, clean, lint-free cloth to wipe the screen.

4. - Don't give any pressure directly to the LCD.

You can buy special anti-scratch cloths and special sprays with which to clean LCD screens. For example MSI provides a Micro Fiber anti-scratch cleaning cloth with its laptop PCs, which can also be purchased, and One Clean Screen Cleaner consists of a 30ml spray that provides and alcohol-free cleaning fluid and a microfibre anti-scratch sponge that is used to clean the sprayed screen.

How I clean my LCD screen

On a matt or gloss LCD screen, I use a damp tea towel or a piece of cotton wool dipped in distilled water and squeezed out so that isn't full of water. With the monitor switched off, I move the wad of cotton wool horizontally across the screen as if I am painting a wall with a roller horizontally. I don't apply much pressure. If some dirt isn't rubbed away after the first pass, I go over it until it disappears. Then I use a piece of dry cotton wool in the same way. After doing that, no water marks can be seen. If there are persistent marks, I use a damp tea towel to remove them.

The specifications of LCD monitors with low pixel response times

The Response Time monitors is down to 2ms [ms = milliseconds. 1ms is a thousandth of a second] for very affordable LCD monitors. The lower the Response Time, the better the quality of the images, especially when playing graphics-intensive PC games.

Here are the typical specifications for a 17" LCD monitor:

Viewsonic VX724 17" LCD Monitor (MO-041-VS). - "ViewSonic has broken the boundaries of XTREME PERFORMANCE WITH AN ASTOUNDING, INDUSTRY-LEADING 4MS RESPONSE TIME with smooth broadcast-quality and full-motion video. The VX724, 17" XTREME LCD display combines innovative Dynamic Structure™ and Amplified Impulse™ technologies to replace blurs and ghosts with pure, vibrant motion. Features like these are CAPTIVATING IN GRAPHIC-INTENSIVE APPLICATIONS LIKE GAMES AND VIDEOS. OptiSync® technology further enhances this display's appeal by enabling connections to multiple digital and analogue video sources. The VX724 also features 1280 x 1024 native resolution, high brightness and contrast ratios as well as wide viewing angles. Choose high performance features in an elegant package with the 4ms VX724 display. - 1280x1024 Optimum Resolution - 500:1 Contrast Ratio - Viewing Angle 160° horizontal, 160° vertical - 4ms G2G Response Time - 300 cd/m2 Brightness - One Analog Input [D-sub VGA] - One DVI-D Input - DVI Cable Included - 3 Years On-Site Warranty."

****

Here are the typical specifications for a 19" LCD monitor:

Samsung SM-940BF 19" LCD Monitor - "Silver/Black (MO-041-SA) The Samsung SyncMaster 940b Series is a 19-inch analog and digital TFT-LCD monitor delivering crisp, clean text and bright, vivid colors. The SyncMaster 940b Series display offers the option of using either a digital or analog interface for viewing images and text. The Digital Video Interface (DVI) ensures a shaper, cleaner image and a more accurate representation of the original video source. Since video starts out digital in a PC graphics card, the digital output is directly interfaced to the digital input of the LCD panel and always provides the optimum quality image. In addition, no adjustments are required with a digital display, even when randomly changing resolutions. Input connectors for this display include 15-pin D-sub and DVI-D. - 1280 x 1024 Optimum Resolution - 700:1 Contrast Ratio - Viewing Angle 160° horizontal, 160° vertical - 2ms Response Time - 300 cd/m2 Brightness - One Analogue [D-sub VGA] Input - One DVI-D Input - 3 Years On-Site Warranty."

Some LCD monitors come with inbuilt speakers and some can be rotated through 90 degrees

Some LCD monitors have inbuilt speakers and a headphone socket that can be very handy if, say, you're using a website that provides sound, such as the free language tutorials on http://www.bbc.co.uk. The internal speakers, of course, have to be connected to a sound card, just as external speakers have to be.

The inbuilt speakers in an LCD monitor are fine for the sound produced by websites, but if you want to use your computer to watch DVD movies, most authoratitive sources recommend the use of a separate sound system.

Most standard (non-widescreen) LCD monitors have an aspect ratio (see further down the page for more information on this) of 4:3, simply because the standard display resolutions (see further down the page for more information on this) such as 800X600 and 1024X768 have a height-to-width ratio of 4:3, which is what the aspect ratio is.

An aspect ratio of 4:3 is equivalent to the screen being viewed in the landscape printing orientation, and as such is ideal for dealing with documents, such as large spreadsheets, that are wider than they are high. But most document pages are best viewed in the portrait orientation, in which the height of the page is greater than its width. Therefore, some LCD monitors can be rotated through 90 degrees so that they can be viewed in the portrait orientation.

The monitors that allow rotation usually also come with the software that changes the output from the computer to match the portrait orientation of the screen. Pivot Pro is a good example of such software.

How to use dual/multiple monitors in Windows XP and Windows Vista

If you want to use multiple monitors with a desktop or a laptop PC to view different applications at the same time, this can be done with Windows 98, Windows Me, Windows XP, and Windows Vista.

For more information on how to do it, read an article called Using Multiple Monitors with Windows XP on Microsoft's site. Here are two more useful articles on using multiple monitors in Windows XP:

How To Configure and Use Multiple Monitors in Windows XP -

http://support.microsoft.com/kb/307873

How to Install Dual Monitors [Video] - http://videos.howstuffworks.com/computer

Troubleshoot multiple monitor problems -

http://windowshelp.microsoft.com/Windows/en-US/...

Using multiple monitors in Windows XP is a plug-and play operation. You can install two or three video cards in the computer's PCI Express slots and then plug in three monitors, and XP recognises them almost every time. However, doing that in the Windows Vista Home Premium or Vista Ultimate versions, which support the Aero Glass feature, is not so easy because the video cards must use the same WDDM driver. If the system is running two Aero-capable video cards that use different WDDM drivers (e.g., an ATI card and an nVidia card), Vista disables one of them.

However, it is possible run multiple monitors in Vista with Aero Glass, but the implementation is not as perfect as it is with Windows XP. The following two webpages deal with this topic in more detail:

#5: Why is it so much harder to use multiple monitors [with Windows Vista]? -

http://articles.techrepublic.com.com/5100-10877-6155343-2.html

MultiMonitor Support and Windows Vista -

http://www.microsoft.com/whdc/device/display/multimonVista.mspx

If you need to know how it can be done in Windows 98 or Windows Me, use a search term such as two + monitors + "windows 98", as is, in the Google search box provided at the top of this page (with its Web radio button enabled).

Visit the Using Windows Vista section of this site for information on the new versions of Windows.

Using an LCD computer monitor as a TV, and using an LCD TV as a PC monitor

Using a computer monitor as a television

You can use an LCD computer monitor as a TV by attaching it to an internal PCI TV tuner card that is installed in a free PCI slot on the computer's motherboard.

Some AGP video cards, such as the Sapphire All-In-Wonder 9800 Pro, and some PCI Express video cards have integrated TV tuners that can accelerate DVD playback and allow video/image editing.

Sapphire All-In-Wonder 9800 Pro - review:

http://www.3dvelocity.com/reviews/sapphire9800aiw/thebeast.htm

You can search for other examples by using a search phrase such as: "pci express" + "video card" + "tv tuner" (as is) in the Google search box provided at the top of this page.

Of course, if you use a PCI or PCI Express card to watch television, the computer has to be switched on. You have to use an external adapter of the kind explained below in order to watch television with the computer switched off.

These can be provided by the manufacturer of the monitor, or by a third-party manufacturer. For example, IIyama provode TV adapters for its ProLite LCD PC monitors. A supplier of IIyama monitors and their TV tuners in the UK is http://www.microdirect.com/.

Examples of external TV tuners made by third-party manufacturers are the TV Jockey from Startech, the Combi TV-PC Pop View from Trust, and the AVerTVBox9 from Avermedia. The input connectors they offer are the standard RF port that all TV sets and VHS video recorders have, composite, component video, D-sub (the standard analog VGA connector on a video card), 2x line in (3.5mm jack and RCA pair), and the output connectors they offer are D-sub, line out (3.5mm jack), and headphones.

A good site to find out what kinds of external options are available is http://www.averm.co.uk/.

When choosing an PC LCD monitor for use as a TV, unless you want to use a special sound system, it's advisable to choose one that has internal speakers. Moreover, note that most LCD computer monitors have an Aspect Ratio of 4:3, which is fine for ordinary TV viewing, but if used for widescreen movies that require an Aspect Ratio of 16:9, you will see banding - empty bands showing at the top and the bottom of the screen.

Click here! to read additional information on this site on TV tuner cards.

Using an LCD TV as a computer monitor

If you want to use an LCD TV as a computer monitor, this is possible because many of them have a D-sub video port that can be attached to a computer's video card, and some also have a digital DVI port, but note that the native resolutions should be 1024X768 for a 15" screen, and 1280X1024 for a 17" and a 19" screen.

If a 15" (or higher) LCD TV only supports a 640X480 or a 800X600 native resolution, only 800X600 is barely suitable for a computer display on a 15" screen. A native resolution of 640X480 on a 14" or 15" LCD screen would make Windows or Linux use a horizontal scroll bar to access the information that can't be shown, because the lower the resolution the less the amount of information that can be displayed on the screen.

If the LCD TV doesn't have any of the ports for an analog or digital PC connection, it can't be used as PC monitor. See the Video/Graphics pages on this site for more information on computer video and graphics.

PROBLEM

How can I use HDMI with my PC?

I want to buy an LCD TV. I have found one that is HD-ready (ready to receive High Definition TV signals), but it only has an HDMI input, not the DVI input that my PC has. What is HDMI and is there a way I can connect my PC to such an LCD TV?

Answer

HDMI is the latest digital video connector. The cable is similar in appearance to a USB cable, and it is easier to connect than a DVI cable. It will eventually be the only way in which to connect set-top boxes and DVD players to a TV.

Along with digital video, HDMI carries surround sound over the same cable, which means that only a single connection is required for sound and vision. However, a DVI connection can only carry video. HDMI connections support HDCP, the new Digital Rights Management (DRM) copy-protection system for High-Definition content. HDMI is compatible with DVI, but you won't have sound. A DVI-to-HDMI converter can be purchased for around £20 from good electronics goods stores.

Connecting an Xbox to an LCD monitor

In order to connect an Xbox to an LCD monitor you need a VGA converter unit that is compatible with the monitor. For example, if the VGA converter has a maximum vertical refresh output of 50Hz, you won't be able to use it with an Iiyama ProLite 481S LCD monitor, because it only accepts vertical refresh rates of between 56Hz and 80Hz. AVT's 3300 XGAwesome converter is compatible with that monitor. Knowing that, you should be able to find converters that are compatible with your monitor.

You should also be able to use an external TV tuner, such as AVermedia's AverTV Box 9, to connect an Xbox to an LCD monitor. Visit this site for more information on it and other external units: http://www.averm.co.uk/.

The majority of external TV tuners have an auxilliary video input connection, usually via composite video connection, or via an S-video connection on the more expensive units. You connect the Xbox to one of those inputs and the signal should pass through to the LCD monitor.

Note that the cheaper units might cause a slight delay, which wouldn't spoil the quality of video output, but it might reduce gaming performance. However, AVermedia claims that its AverTV Box 9 is ideal for use with an Xbox.

Most monitors, CRT or LCD, come with a three-year on-site, or return-to-base warranty, or a mixture of the two types of warranty. For instance, the warranty might be on-site for its first year, and then become a return-to-base warranty for the remaining two years.

Note well that in many cases the warranty for the monitor included with a brand-name computer, such as Dell, HP, and Compaq, has a three-year warranty provided by its manufacturer, even though the computer itself is only covered by a standard one-year warranty.

For more information on this subject see the Warranty page of this site.

Monitor-testing software and hardware

Some fairly recent monitors have a built-in array of test patterns that can fully test all of the modes, resolutions, colour depths, etc., of its hardware. They can also allow on-screen adjustments, such as rotation, pincushion, keystone, convergence, etc. Refer to the user's manual, or experiment with monitor's hardware control functions to find out if your monitor provides these tests. If the monitor has them, you won't need to use a software-based set of tests.

There are many free software diagnostic programs available for monitors. DirectX, the gaming software installed by default in Windows, installs one. To run it, enter dxdiag in the Start => Run box in Windows 9x and Windows XP. In Windows Vista, enter dxdiag in the Start => Start Search box.

Video cards can also install a diagnostic program when the card's drivers are installed. To find out if is this is the case with the video card installed in your computer, right-click My Computer, click Properties, and then click Hardware => Device Manager in Windows XP, but just click the Device Manager tab of System Properties window in Windows 9x systems. Open the Display adapters (in Windows 9x and Windows XP), and double-click the entry for the video card. There'll be a Diagnostics tab in the applet that comes up.

In Windows Vista, thgere are several ways of opening the Device Manager. The quickest access is probably provided by looking under Hardware and Sound in the Control Panel, or by entering devmgmt.msc in the Start => Start Search box.

The Nokia Monitor Testing Tool is one of many free diagnostic testing tools. Its Help file shows the Nokia Corp. from Sweden as the site to obtain it, but I have yet to find the file on any Nokia site. The tool comes as a download-and-install program, but you can take the three small files and use them from a floppy disk so that you can test the monitor without loading an operating system. It has a good set of the standard test patterns.

It's available from many locations, such as:

http://www.majorgeeks.com/

You can find other diagnostic programs by using a search phrase, such as free + monitor + testing + tool in the Google search box at the top of this page with its Web radio button enabled.

KVM switches

How to use two or more computers with one keyboard, monitor, and mouse

If you want to access more than one computer but don't need to network them, there is a little-known device called a KVM switch that allows the operation of two or more computers from one set of keyboard - monitor - and mouse. The letters KVM stand for keyboard video and mouse, I suppose because KVM sounds better than KMM. Some of these switches can allow thousands of computers to be accessed in this way, and some of them even allow the use of one sound card and one set of speakers. The computers and the one set of keyboard, monitor and mouse are linked to the KVM switch, and key toggles are used to switch from one computer to another. All of the computers are tricked into thinking that they have sole use of the keyboard, monitor, and mouse. This is an invaluable aid if you need to use more than one computer but you don't need to have them networked.

You can purchase KVM switches from all of the larger online electronics and computer businesses. A four-computer model is typically priced from £36/$60 to £75/$125, and a two-computer unit is about half that price. Note that the more expensive units usually have superior cables and shielding from electronic interference than the less expensive units.

KVM Switches that do DVI from Aten -

"Using a KVM switch to work on two or more computers with a single keyboard, mouse and monitor can certainly make life easier. However, we had to wait a long time for KVM switchboxes to catch up with modern technology, such as the all-digital visual interface (DVI) connectors for flat panel displays. Until recently, users had no choice but to use only D-15 analog VGA connectors with KVMs - a relic of the bygone CRT era. But such devices now not only enable switching among multiple sound and USB sources, they can even switch between systems with two monitors attached." -

http://www.tomshardware.co.uk/...review-1370.html

Clutter Rescue: 2 Port KVM Switches -

http://www.tomshardware.co.uk/clutter-rescue,review-935.html

Belkin - http://www.belkin.co.uk/ - make a good line of KVM Switches that make use of the PS/2 or USB computer ports.

PC Buyer Beware! Copyright © Eric Legge 2004-2009. All rights reserved.