by October 8, 2010 0 comments



LCD monitors are common these days as they are cost effective in the long run. They consume about 1/3 of the power consumed by CRT, so for businesses it brings price advantage over a long time. LCDs are much thinner than CRTs and thus save valuable desk space. Not only thinner, they are lighter than CRTs, hence are also more portable. Their image is crisper because each pixel is displayed by a specific set of liquid crystal cells. LCD monitors have finally taken over CRTs in the marketplace. And now the chances are good that next monitor for your office will be an LCD.

LCD displays, use liquid crystal sandwiched between thin polarized sheets for the display. The pixels on the screen are controlled electrically using transistors. LCD technology is less emissive than the CRT, hence it makes for more restful viewing over a long time and causes less eyestrain. LCDs are usually much brighter than CRTs, since they use just one simple backlight but sacrifice on the viewing angle.

How we tested
We used J&W 790GX Extreme Desktop Motherboard with AMD Phenom II X4 955 Processor (800 MHz) for our exploits. We connected all LCD monitors to the native display port of the motherboard (VGA/DVI). We connected Kingston 2GB DDR2 RAM with Seagate 7200 RPM 120 GB HDD. Windows XP SP3 was our choice of OS for our tests.

Displaymate benchmark
For checking quality of display we used Displaymate benchmark. In this benchmark we used two relevant parts. First we used ‘set up display’ to calibrate monitors for best possible display and then used ‘Video obstacle course’ that runs different tests for known issues like banding, color regeneration, flicker, noise, brightness level, focus, dot moire interference, dead pixels etc. Two important points here are that perfect uniform color regeneration is impossible for any LCD and best performance of an LCD can be obtained at maximum resolution supported.

Power consumption
As LCD monitors are popular for their low power consumption, we tested these monitions for minimum and maximum power consumption. A standard power meter was connected to the monitors. To calculate maximum power consumption we used the Chekemon benchmark. The power consumption setting of this benchmark is an ideal scenario to test out the maximum power being consumed by the monitor. On the other hand, for minimum power we checked power consumed in sleep mode.

Buying tips
Your decision to buy may be shaped by budget limitations, how you’ll use the computer, aesthetics, space constraints, environmental concerns–or a combination of all these factors. Some aspects about LCD monitors that you must consider before making any purchase are given below.

Screen-Size
Though 15” monitors are good enough for regular office usage, more than this screen size can result in better efficiency. If major part of work in your organization is graphical in nature, a 17” or more screen can give better visibility. One must remember that the size of screen is directly proportional to the amount you have to pay. The diagonal measurement of an LCD is the same as its viewable area, so there’s no loss of the traditional inch or so behind the monitor’s faceplate or bezel. This combination makes any LCD a match for a CRT 2 to 3 inches larger.

Aspect Ratio
Ratio of width to height is known as aspect ratio. Conventional CRT monitors come with a 4:3 or 5:4 ratio but nowadays widescreen displays with a typical aspect ratio of 16:9 are more popular. The benefit of using widescreen besides better video display is that one can simultaneously view more than one monitors by keeping them side by side.

Resolution
Ideally, the minimum supported resolution should be at least 1024 x 768 with a refresh rate of at least 60 Hz. Most LCD monitors allow you to scale images of other resolutions but you’ll get the sharpest result if you stick to the native resolution.

Viewing Angle
This is the maximum angle from which you can view the LCD without any deterioration in display quality. Here, you need to check for both the horizontal and vertical viewing angles. If you need to see the image when you’re not directly in front of the display, look for a design with a wider viewing angle. The higher the viewing angle, the better is the monitor. LCD with a viewing angle of more than 160 degrees is recommended.

Dot Pitch
Dot pitch refers to the distance between each pixel or pocket. The less space between each pocket gives you a better picture with a crisper image and more detail. A better Dot Pitch would be needed for monitors used by graphics users.

Manual Adjust
There are LCD monitors in market that can be rotated 90 degrees giving two different modes of display horizontal (landscape) and vertical(portrait) with the help of software. This feature can be handy if you have to view long spread sheets or web pages. One more important criteria is the ability to adjust an LCD monitor at different angels and height so that it is comfortable to view. Monitors that provide this tilt/adjust capability are more preferred as a convenience feature for users.

Digital Input
If you want a clearer display, you might want to check whether the monitor has a digital input in addition to the regular analog that connects to most display cards. A typical computer display card generates the display information and stores it as digital data in a frame buffer. If the LCD monitor is attached to the VGA port then this digital data is converted to analog and then at the monitor it is converted back to digital. This conversion leads to loss in signal quality. The DVI digital interface was developed to eliminate the conversion from digital to analog and back again, so that you get a perfect image.

Control Panel
With every display one needs to make some adjustments for contrast or for brightness. Most manufactures are now providing On-Screen Display (OSD) menu for doing such settings. Check that the OSD controls are easy to use, quick to learn and the keys on front panel are not flimsy. Another feature is the ability to lock these controls so that nobody else can fiddle with your settings. If you’re buying a monitor for design work, then ensure that it has color temperature settings.

Audio
Most vendors now provide built-in speakers or headphone jacks on the display monitor. For office purposes built-in speakers are not needed but still for occasional listening they could be an advantage.

Brightness and Contrast ratio
Both these parameters are important for image quality. While brightness is measured in nits or candelas per square meters, contrast ratio is the ratio indicates the difference in light intensity between the darkest black and brightest white. Now more brightness means better image quality. For regular use, value of 250 cd per meter square is enough. On the other hand, go for a 400:1 contrast ratio.

Pixel response rate
Also known as response time, it is the time taken by the crystals of LCD monitor to change color. Response time is measured in milliseconds and it varies between 2 to 16 ms. Lower value of response rate results in lower ghosting and streaking and hence better viewing quality. If most of the official work in your organization revolves around Internet surfing and document processing then response time between 8 to 16 ms is sufficient but in case you are into video editing or gaming then the response time should be not more than 5 ms.

Price and Warranty
Other important factor to be considered is the price and type of warranty a vendor provides. These types of warranties could vary from technical support to full replacement of the device.

Ergonomics and Build Quality
Here, you might want to check the placing and number of buttons for accessing the monitor’s OSD, and the quality of keys. We’ve found buttons in monitors that are so hard to press that you have to literally hold the monitor with your other hand so that it doesn’t move while pressing them.

Other features
Check whether the monitor can be wall mounted, in case you want to use it as a display for corporate presentations or in kiosks. Check the bezel size in case you plan to put it on a cramped desktop. Some monitors come with extra features like a USB hub to extend your USB ports from behind your PC, so that they’re more easily reachable. Nowadays LED monitors are becoming more popular which have the added benefit of energy saving and brighter backlighting.

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