Contact: John Blair, john.blair@nist.gov
FOR IMMEDIATE RELEASE: NIST 97-02
Jan. 24, 1997
Contact: John Blair NEW NIST MEASUREMENT
(301) 975-4261 TECHNIQUE GIVES INDUSTRY
john.blair@nist.gov 'CLEARER VIEW' TO BETTER
FLAT-PANEL DISPLAYS
Just how black is the black in that flat-panel display?
Until recently, manufacturers and users of high-contrast
electronic displays, such as those used in laptop computers, were not
sure. Using conventional measurement techniques, manufacturers could not
assess accurately contrast ratio nor could they recognize when their
measurements were in error. Results often varied, fueling complaints and
making comparisons between brands or different technologies difficult.
In addition, the ratio of the luminance of a white area to a black area
on a display is a performance parameter that strongly influences the
perceived quality of a display.
Now, two researchers at the Commerce Department's National
Institute of Standards and Technology have devised a measurement
technique that offers both manufacturers and industrial customers a
means for accurately measuring the contrast ratios of displays in
laptops, airplane cockpits, home entertainment centers and other
applications.
Researcher Edward Kelley determined that the accuracy problem
stemmed from unavoidable reflections in the lens of the measuring
instrument. The reflections, also called veiling glare, were being
introduced by illumination from the nearby lighter areas on the display
surface.
The NIST method designed to eliminate the problem uses an
open-ended cone to reduce substantially the reflections introduced into
the lens system without interfering with the measurements. The cone can
be positioned to reduce the glare to an insignificant amount.
Working with Paul Boynton, Kelley measured a display using
conventional techniques and the newly developed NIST method. The former
resulted in a value of 50 to 1; the latter revealed a more accurate
contrast ratio of 250 to 1.
Boynton says, "We're using this work to help people understand the
importance of developing a firm measurement base in the display
industry. We want them to think more critically about how to make
measurements."
According to Kelley, chair of the Video Electronics Standards
Association flat-panel display measurement standards committee, VESA
members will vote later this year to adopt a new flat-panel display
measurement standard that includes the NIST-developed technique.
For technical information, contact either Edward Kelley, A53
Technology Building, NIST, Gaithersburg, Md. 20899-0001, (301) 975-3842,
e-mail: edward.kelley@nist.gov or Paul Boynton at the same address,
(301) 975-3014, e-mail: paul.boynton@nist.gov.
A non-regulatory agency of the Commerce Department's Technology
Administration, NIST promotes U.S. economic growth by working with
industry to develop and apply technology, measurements and standards.
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