Appeal No. 2002-1849 Page 9
Application No. 09/116,710
From our review of Branca, we find that Branca is directed
to a chromatically-adjusted, holographically illuminated
image-providing display element, including a reflective
holographic diffuser, and color compensation means for effecting
substantially achromatic illumination (col. 1, lines 1-14).
Branca discloses that in conventional devices using LCD displays,
backlighting and edge-lighting are oftentimes the greatest source
of power drain. To reduce energy requirements, conventional
reflectors have been replaced with reflective holographic
diffusers, that are comprised of a holographic transmission
diffuser and a reflection layer. In applications where good
achromaticity is of heightened importance, the illumination
effected by the diffuser is limited by the intrinsic color of the
polarizers incorporated into the display. Branca adds that
perfectly neutral polarizers are uncommon and that more
typically, a synthetic sheet polarizer will have an intrinsic
perceptible hue, i.e., "bluish" or "reddish" (col. col. 2, lines
14-43). As a result, despite the use of a reflective holographic
diffuser to effect an achromic spectral output, transit of
ambient illumination through the liquid crystal element will
result in tainting the light perceived by a viewer (col. 2, lines
44-47). To meet this need, Branca discloses providing additives
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