Summary
Televisions, computers, and telecommunications equipment are merging into advanced systems that enable unforeseen applications in many areas, such as education (remote learning), entertainment (3D movies), and medicine (remote surgery). Displays are everywhere – thermal imagers for firefighters, airplane cockpits, and your doctor’s office. To facilitate worldwide commerce in displays, methods for characterizing display quality are needed to ensure that a display will work under the available lighting conditions – ranging from daylight for cell phone users to smoky buildings for firefighters. To ensure equity in the marketplace, NIST is working with industry to develop standards and the necessary measurement tools to characterize displays under a wide variety of conditions.

Description
The United States is a major user of electronic displays for medical, automotive, avionics, consumer, and computational use. The first three applications require stringent testing to ensure adequate performance for viewing and interpreting digital images. For example, medical radiologists require displays that will provide accurate contrast and resolution of digital images; correct medical diagnoses depend upon it. In addition, well-defined methods for specification and verification of display quality are necessary to enable worldwide commerce of displays. Sound metrology tools are urgently needed in this highly competitive environment of new and emerging display technologies to ensure quantitative metrics for comparing the performance of emerging technologies. Further, universally recognized and accepted standard documents are needed to provide customers with the necessary knowledge to make informed purchases for their applications.

To address these needs, we have focused our efforts on developing a common set of best practices in critical measurement areas. These areas include reflection metrology and stray light management (veiling glare, ambient contributions), and the development of transfer standards and devices to facilitate direct comparisons of different display technologies under different lighting conditions –from the brilliant daylight in an airplane cockpit to the dark automobile interior at night.

In the area of reflection metrology, we have developed quantitative methods based upon the bidirectional reflectance distribution function. We are using a three-component reflection model of specular (with a distinct virtual image proportional to the luminance of the source), Lambertian (perfectly diffuse, luminance proportional to the illuminance), and haze (a diffuse intermediate state of between specular and Lambertian that is peaked in the specular direction but proportional to the illuminance). We have extended these techniques to address issues related to daylight readability of displays.

More on Flat Panel Display Metrology is available from the Flat Panel Display Laboratory Web site.