Choosing the Laptop Computer With the Best Screen

Expert Says VESA Standard Offers Hints On What to Look For In A Display

PRINCETON, N.J., Nov. 19, 1999--Laptop computers with big bright screens are hot sellers today. But you'll be staring at the screen on your new laptop for hours a day. How can you choose the best one?

"There are ways to compare LCD flat-panel displays, which is what laptop screens are, just by looking at them," says Mike Grote, Member of Technical Staff at Sarnoff Corporation. "The Video Electronic Standards Association (VESA) standards for measuring flat-panel displays tell us what to look for."

Grote was on the team that helped create the VESA standards. His work was done at the National Information Display Laboratory (NIDL), which is hosted by Sarnoff. (NIDL is a National Technology Alliance center for excellence established by the National Imagery and Mapping Agency.)

Grote suggests that you compare a few screens side-by-side under identical lighting before you buy. Check these seven performance areas, spotlighted as important in the VESA standards.

1. Brightness and Contrast

Today's active matrix displays outshine the passive screens on older laptops, but there is such a thing as too bright. To make text look crisp, clear, and beautifully contrasted, a manufacturer can boost display contrast so high that its viewing quality falls sadly short on photographic pictures. Make sure to choose a display that does well on both pictures and text.

2. Ambient contrast ratio

This describes how a screen behaves in a lit room. If a display appears washed out under strong lighting, and you usually work in bright environments, look for one that holds up under lights.

3. Viewing angle

How far off center can you move before the image on screen dims or reverses lights and darks? If you regularly collaborate with others around the computer, get the widest viewing angle possible so everyone can see.

4. Cross-talk or shadowing

Look at an image with high contrast to see if strong shapes create visible "ghosts" in adjacent areas. Grote says this effect is seen in some low-cost passive displays. It's been largely eliminated in today's active matrix LCD panels.

5. Response time

A slow screen refresh is a real annoyance when viewing motion pictures. Unfortunately, LCD displays have longer lag times than conventional monitors, but you can limit the wait by choosing the fastest.

6. Color tracking

On LCD displays, the color tones change as you increase brightness. Look for a display that minimizes this color shift. Also look for good color uniformity across the screen, from center to corners.

7. Gray-scale capability

Grote has seen one LCD panel recently that couldn't display many shades of gray. Everything tended to be either black or white. Call up a monochrome picture with lots of middle tones to see how well the screen handles them.

You probably won't find a display that's the clear winner in every single category. But you should be able to identify one or more that score well across the board. From among these choose the one that's tops in the areas that matter most to you.

"Eventually, when more manufacturers adopt the VESA Flat Panel Display Measurements Standard, you'll be able to pick the best LCD screen just by looking at published specs," says Grote. "But until then, the things we learned while developing the standard will help you find the display you want on your own."

About Sarnoff Corporation

Sarnoff Corporation creates and commercializes electronic, biomedical and information technology. Founded in 1942 as RCA Laboratories, Sarnoff has been a wholly-owned, for-profit subsidiary of SRI International since 1987. The company's decades of innovation include the development of color television and the liquid-crystal display and a leadership role in creating the digital and HDTV standard for the US. Sarnoff now works with a wide variety of industry and government clients to develop and improve specific technologies that will help change the world. A key element of the company's overall strategy is the founding of new companies that bring its technologies to market. Fourteen such companies are in various stages of development.

About the National Information Display Laboratory (NIDL)

The National Information Display Laboratory (NIDL) brings together commercial and academic leaders in advanced display hardware, softcopy information processing tools, and information collaboration and communication techniques to help government users better accomplish their jobs. In establishing the NIDL in 1990, the government sought to leverage the resources of the world's commercial and university leaders in crucial technologies. The NIDL focuses on government users' needs which are often several years in advance of those of the commercial marketplace. One of the goals of the NIDL is to foster research in advanced capabilities in a manner that provides incentives for commercialization.