Using Flat Panel Displays in Education
(also called Flat Screens, LCD Displays, TFT Panels, Thin Screens)
by Keith Lightbody - Facilities Consultant - last updated 5 September 2008
Flat panel displays are becoming ever more popular. In homes and offices Liquid Crystal Display (LCD) screens are rapidly replacing the heavy and bulky Cathode Ray Tube (CRT) glass screens - in some large offices every single user has switched to a flat screen within 2 years - an incredibly rapid rate of uptake of new technology! Flat LCD screens look very stylish and take up less space but are they worth the extra cost for schools? Prices have dropped considerably but what benefits are offered for the classroom? There are some issues - a classroom is different to an office or home - hence this article!
The most commonly available flat panel LCD computer displays use Thin Film Transistor (TFT) technology to produce a high quality digital image. The LCD screen requires greater care - it should not be touched or prodded! For years people have safely used a finger tip or pen to touch a spot on a solid glass CRT screen - many people continue this habit with LCD screens. LCD screens are also used in laptop computers and palm pilots/pocket PCs/Personal Digital Assistants (PDAs). Each pixel on the screen is commonly made up of 3 layers or cells of red , green and blue transistors. A typical 15" screen has 1024 by 768 pixels and a typical 17" screen has 1280 by 1024 pixels. On LCD panels the maximum native resolution (e.g. 1024 x 768 pixels on a 15" screen) must be used for best results - setting to a non-native resolution (e.g. 800 x 600 pixels) produces an inferior result.
Flat Panel Displays
|Advantages of LCD Displays||Disadvantages of LCD Displays|
|* use very little desk space||* more expensive (typically up to twice the cost)|
|* flicker free text||* fixed native resolution e.g. 15 " 1024
(can not maintain same quality when reset for vision impaired student or older person)
|* new technology brighter with better colours||soft surface more easily damaged, difficult to clean|
|emits less radiation||high security risk (compact, expensive, attractive target for thieves)|
|uses about one third of the energy of CRT||possible to get 'dead' pixels (1 - 4 may be considered 'fully operational' under some warranties)|
|larger viewable size
(17" LCD screen is comparable to 19" CRT monitor)
|inbuilt speakers currently less common|
|clearer, brighter - may be more restful on eyes||poorer quality video or poorer display of high speed action
(higher motion blur - even with suitable video card, minimised by fully digital graphics card and LCD display)
|can display digital signal without analogue conversion
(requires graphics card with digital signal e.g. DVI)
|displays older than 4 years do decline somewhat but it appears much worse if compared side by side with a new LCD screen using the latest technology|
However there are still many reasons for schools to
use the traditional Cathode Ray Tube (CRT) monitors. These screens have an
electron gun that fires a beam of electrons onto a colour phosphor. Line after
line of the image is 'drawn' on the screen at high speed - the 'whole' image
is seen by the human eye due to persistence of vision. CRT monitors can require
adjustment for position and focus but typically outlast any computer purchased
at the same time. Older models had curved glass screens but recent models
have a relatively flat surface. Although there is a growing trend among computer
suppliers to reduce or discontinue CRTs, schools will continue to find CRT
monitors very reliable, robust and cost effective. CRT monitors can still
meet computer display needs in classrooms for a few years yet! However after 4 years the display quality will have diminished.
|Advantages of CRT Monitors||Disadvantages of CRT Monitors|
|* cheaper (typically half the cost)||* uses a lot of desk space|
|* crisp image at wide range of resolutions
(e.g. 640 by 480 up to 1280 by 1024)
|* flicker can affect user|
|* display good quality video or high speed action
(with suitable video card)
|* emits more radiation
(even stronger behind the monitor)
|* lower security risk (heavy, bulky, relatively cheap)||requires analogue signal (e.g. VGA)|
|glass screen less easily damaged in classrooms||actual viewable size smaller than measured glass
(casing often covers part of the glass face)
|inbuilt speakers widely available
(less hassle than separate speakers in school environment)
|curved screens subject to reflections and glare|
|widespread availability of service and parts||heavy, bulky, difficult to move|
|better colour accuracy||displays older than 4 years decline in brightness and colour|
|signal can be affected by magnetic fields|
- check the native resolution before you buy a flat panel display - a 17" flat panel typically has a native resolution of 1280 x 1024 so try setting your existing CRT monitor to 1280 instead of 1024, 800 or 640 - how do your applications look? - what will your email look like at this resolution? - it is not easily resized!
- make sure that the input connections on your flat panel display are compatible with those on your graphics card.
- check any flat panel display prior to purchase for 'dead' pixels - they may not be covered under warranty
(there have been cases where suppliers consider some dead pixels acceptable)
- secure flat panel displays to furniture to prevent theft. One company in Australia that offers a range of security lock down kits for schools is PC Locs http://www.computerlocks.net/index.htm
- a totally digital signal (PC to graphics card to display) produces better picture quality
(when compared to a digital PC signal converted to an analogue graphics card signal and then converted to a digital display)
Multiple LCD displays
Although normally only relevant to office workers be aware of the use of dual displays. Two smaller monitors are cheaper than one larger monitor so a large display space can be achieved very economically (e.g. for CAD design, advanced video editing). In the classroom it may also be relevant for some collaborative tasks. Setup is easy as modern operating systems have built in support for multiple monitors. Multiple LCD screens easily fit on a users desk. Some recent graphics cards support single, dual, triple or even a quad display desktop.
Large LCD displays (over 22")
Very large LCD displays may allow for applications to be more easily read at the optimal native resolution.
- Glossary http://pcsupport.about.com/od/glossary/g/lcd.htm
- Glossary http://www.futureelectronics.com/LCDDisplay/glossary.asp
- PC TechGuide http://www.pctechguide.com/07panels_LCDs.htm
This article was written and updated after purchasing and using both flat panel displays and CRT monitors over a 12 month period. At present I find a 17" flat panel displays require some adjustments to software (as text in applications that do not readily allow resizing is too small for my ageing eyesight) but a 15" flat panel display set at 1024 x 768 is likely to be easily readable in common applications. Single or dual flat panel LCD displays are great for workplaces such as banks, hospitals, offices and point of sale terminals. In certain situations in schools they are ideal but for general classroom use in schools with limited budgets people need to consider the visually impaired, check the benefits and be confident that damage to the delicate screen or theft can be prevented. First published online in January 2002. Currently up to 20 people per week visit this site. Statistics on usage of this site were gathered by ozlog software.
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