Optical element and display device provided with said optical element

Abstract

An optical element (8) is provided on a substrate, for example a display screen (3) of a display device (1), which optical element comprises a light-transmitting layer whose transmission in the visible region varies in response to a change in ambient light. The optical element (8) is characterized in that it further comprises a colored coating which selectively absorbs light in the visible region. The colored coating has such an absorption characteristic that the color coordinates (x;y) of the combination of the light-transmitting layer and the colored coating vary in such a way, as a result of a variation in ambient light, that a line, which interconnects the color coordinates, is partly situated in an elliptical area with achromatic point (0.333;0.333) in the color triangle, which ellipse comprises a major axis and a minor axis, which major axis terminates in (0.30;0.28) and (0.36;0.38) and the eccentricity of which ranges between 2 and 3. Preferably, the line is situated predominantly in the elliptical area. The invention is important, in particular, for optical elements which serve to reduce the transmission of light, and which comprise an electrochromic element or a photochromic element.

Dependencies are inferred from the claim text.