Proposed Diffuse Ambient Contrast Measurement Methods for Flat Panel Displays.

摘要

We want to measure the contrast (ratio of white to black) of a display under uniform diffuse illumination to provide an indication of the legibility of the display under diffuse-ambient lighting conditions. This is the type of illumination that can be generated by a bright overcast day. Several methods can be used to make this kind of measurement. The methods vary depending upon the way the diffuse illumination is provided. We show three methods that should provide ambient contrast measurement results with an uncertainty of no greater than 6% (expanded uncertainty with a coverage factor of two-in the past described as a two-sigma uncertainty). These are the (1) Integrating Sphere Method, (2) Open Box Method, and (3) Sampling Sphere Method. We will describe how the measurement results are properly scaled, discuss the light sources to be used, obtain the starting conditions in Step 0, and detail the methods. These methods can be applied to both emissive and reflective displays. In the following, we show a flat panel display (FPD) being measured, but these results are applicable to all direct-view displays.