Appeal No. 2001-1116
Application No. 09/070,222
Chiu et al. discloses a multicolor projection arrangement comprising light
integration means (56), a polarizing beam splitter, and a color separation prism
arrangement for directing light to plural reflective liquid crystal display panels. Film
(40) acts as a polarization conversion system for converting the light from the source
into passing light of a single polarization.
Chiu et al. do not specify the use of an LCD with diffusive properties, such as
a reflective polymer dispersed liquid crystal (PDLC) panel.
Kobayashi et al. teach a reflective polymer dispersed liquid crystal display
system wherein a quarter wave plate (3108) is positioned between a light entrance
side of the display and a reflective portion (3109) of the display pixels (See Figure
34A).
It would have been obvious to one of ordinary skill in the art at the time of
the invention to modify the apparatus of Chiu et al. by the use of known types of
reflective modulators, such as a PDLC display as taught by Kobayashi et al. In [sic,
in] order to obtain enhanced contrast in a projection system.
In the PDLC display disclosed by Kobayashi (Figure 34A), the quarter-wave plate 3108 is
located between the display panel and a reflector plate 3109. The reflector plate 3109 is an
aluminum reflector layer that is deposited onto a surface of quarter-wave plate 3108 (column 46,
lines 48 through 55). Although Chiu, like Kobayashi, uses a quarter-wave plate, Chiu arranges the
quarter wave plate 48 between the polarizing beam splitter 22 and the projection lens 38 (column 4,
lines 56 through 67).
Appellants argue (brief, page 8) that:
The projection display system of the Chiu et al. patent differs from the
projection display system defined by Claim 1 in the failure to teach, or even suggest
two essential elements of the claimed system. These are a modulating system having
a liquid crystalline reflective image display panel having pixels having reflective
portions and portions which can be switched between a transparent state and a
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