METROLOGY
Overview:
Our efforts are to provide robust measurement methods of display reflection ultimately based upon the bidirectional reflectance distribution function (BRDF). 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). Discussions of other reflection components encountered in display work should be forthcoming.
Publications:
Diffuse Reflectance and Ambient Contrast Measurements Using a Sampling Sphere: (ADEAC06_Sampling_Sphere_2-1.pdf) -- To avoid having to try to fit a large display into a large integrating sphere, a sampling sphere may be used to measure the diffuse reflectance of a display. However, there are some subtleties that need attention. Citation: E. F. Kelley, "Diffuse Reflectance and Ambient Contrast Measurements Using a Sampling Sphere," Proceedings of the Third Americas Display Engineering and Applications Conference (ADEAC 2006), Society for Information Display, Atlanta, GA, USA, pp. 1-5, October 24,26, 2006.
Display Daylight Ambient Contrast Measurement Methods and Daylight Readability: (Daylight_Readability_JSID.pdf) -- Daylight (Sunlight) ambient contrast measurements are calculated from laboratory measurements of reflection parameters. Daylight is a combination of directed sunlight and diffuse illumination from the sky, ground, etc. Readability is not just a function of ambient contrast. Citation: Edward F. Kelley, Max Lindfors, and John Penczek, "Display Daylight Ambient Contrast Measurement Methods and Daylight Readability," J. Society of Information Display, Vol. 14, No. 11, pp. 1019-1030, November 2006.
Scalability of OLED Fluorescence in Consideration of Sunlight-Readability Reflection Measurements: (SID04-OLED-Fluorescence.pdf) -- We show the linearity of OLED flurescence beyond sunlight levels and how laboratory reflection measurements can be scaled to sunlight levels. We provide an example of a sunlight-readability contrast measurement. Citation: E. F. Kelley and J. Penczek, "Scalability of OLED Fluorescence in Consideration of Sunlight-Readability Reflection Measurements," 2004-SID International Symposium Digest of Technical Papers, Society for Information Display, Paper P.54, Vol. 35, Book 1, pp. 450-453, Seattle, WA, May 25, 2004.
Sensitivity of Display Reflection Measurements to Apparatus Geometry: (SensitivityApparatusGeometry-SID2002.pdf) -- We show how small changes in reflection-measurement apparatus configurations can affect the reflection measurement results--a characterization of robustness. Citation: E. F. Kelley, "Sensitivity of Display Reflection Measurements to Apparatus Geometry," 2002-SID International Symposium Digest of Technical Papers, Society for Information Display, Boston, MA, pp. 140-143, May 19-24, 2002.
Proposed Diffuse Ambient Contrast Measurement Methods for Flat Panel Displays: (Ambient_Contrast_NISTIR6738.pdf) --The measurement of the diffuse reflectance of a display and the contrast under such diffuse illumination is one of the most robust reflection measurements that can be made. A variety of apparatus can be used to obtain essentially the same reflectance value. Citation: E. F. Kelley, "Proposed Diffuse Ambient Contrast Measurement Methods for Flat Panel Displays," NISTIR 6738, 6 pp., April 2001.
The Three Components of Reflection: (IDDM02-ThreeReflectionComponents.pdf) --A tutorial paper introducing the three components of reflection. Citation: E.F.Kelley, G.R.Jones, and T.A.Germer, "The Three Components of Reflection," Informational Display, Vol. 14, No. 10, pp. 24-29, October 1998.
Display Reflectance Model Based on the BRDF: (DisplaysBRDF.PDF) --A paper providing some of the mathematical detail and examples of display BRDFs. Citation: E.F.Kelley, G.R.Jones, and T.A.Germer, "Display Reflectance Model Based on the BRDF," Displays, Vol. 19, No. 1, pp. 27-34, June 30, 1998.
Reflection Measurement Problems Arising from Haze: (SID98ApertureHaze.PDF) --This paper demonstrates that whenever the haze component of reflection is present and non trivial, then the measurement result becomes sensitive to the geometry of the apparatus. Citation: G. R. Jones and E. F. Kelley, "Reflection Measurement Problems Arising from Haze," 1998-SID International Symposium Digest of Technical Papers, Society for Information Display, Vol. 29, pp. 945-946, Anaheim, CA, May 17-22, 1998.
Notes:
1. Also see the lasest seminars or courses here .
2. Considerable research is being done at NIST on the measurement and applications of BRDFs as well as reflections:
Bidirection Optical Scattering Facility
Optical Scattering from Surfaces
SCATMECH: Polarized Light Scattering C++ Class Library
Optical Properties of Materials Measurements
NIST Reference Reflectometer: STARR Facility
Updated 20040614T082930
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