March 2010

There is more to LCD displays than meets the eye

If you are like the rest of us, you go to the store, run down a bunch of computer displays, evaluate as best you can the picture quality presented by each display and then make an emotional selection based on looks, the presence of special features such as speakers, and definitely price. . . .

. . . And then you take it home.

It turns out that there is a lot more to a display than the above – especially when your interests are better served by being aware of the speed (for games) pixel density (for photographs) and viewing angle (for sharing with others).

Considerations of each of the items above will add to the cost of the display, but may be worth the few extra bucks if the feature is of value to you.

Twisted Nematic LCD: Cheapest to Make

In addition to being cheapest, this type of display has reasonable response time and thus ghosting and blurring are minimized. One significant problem is that Twisted Nematic LCD cannot display all 16 million colors but only about ¼ million colors. So the cheapest is not really a good pick if you are into photography and need to see all 16 million colors with the various nuances that would be presented by a good high-pixel camera. Clearly a few extra bucks here would pay off greatly in better enjoyment of your business or hobby of photography.

And while we are at it, the same applies to a video projector. If you are constantly projecting high-quality photographs, you had better purchase a video projector that can do the same job that the camera that took the picture.

And finally, the viewing angle is quite limited on this type of display so if you are attempting to demonstrate something and two or more of you need to see the screen, this is not the LCD panel for you.

In-Plane Switching (IPS) LCD: The next step

If you need to have the full 16-million-color palette as mentioned in the previous section, then you need to invest in something that can do the job – and it will cost a few bucks more.

It will also cost a few bucks more in electrical power as the increased transistor count will cost more to manufacture and also the increased intensity of the backlight will also translate into more power consumption. You won’t find it in a laptop because of the higher power requirements. So do your photographic editing on a desktop computer.

Because of its structure, this display will show 16 million colors without dithering or other tricks to fool the eye.

Vertical Alignment (VA) LCD

This last type, which has only one transistor as compared to the display immediately above, will come in cheaper and will have 140-degrees of viewing angle and eliminate the need for the second transistor for each pixel. Thus, it comes in between the two display technologies above and also consumes less power. It, too, is appropriate for three people to be able to view the screen close up while doing photo work that requires a full palette.

So if you are serious about what level of viewing capability you want to have in front of you for the hours that you will be in front of the display, then it is imperative that you establish what the technology is that is employed in the monitor.

This discussion, so far, has discussed only the criteria for photography. What about gaming, where the requirement is for the rapid switching of myriads of pixels and the suppression of ghosting as a result of too-long persistence?

The key here has to be to review the manufacturer’s specifications on the refresh rate of the screen. It will take a lot of digging to uncover the actual capability of each manufacturer’s capabilities for the gaming world, but the homework will pay off handsomely.

Good Luck!