37.3: Viewing Direction Measurements with Hemispherical Diffuse Illumination on E-Paper Displays.

Viewing direction measurements on reflective e-paper displays under hemispherical diffuse illumination are an essential part of characterizing reflectance under common usage conditions such as outdoor shade, or indirect indoor lighting. This paper proposes a hemispherical diffuse illumination geometry based on splitting a sampling sphere into two hemispheres to allow the light measuring device to be pointed at the display at different angles. First results on e-paper agree well with conventional sampling sphere data, show the effects of top layer and surface reflection, and were used to predict the viewing direction distribution of ambient contrast ratio. [ABSTRACT FROM AUTHOR]