Appeal No. 2004-1069 Page 8
Application No. 09/569,616
the surface from which light is emitted from the light expanding system, e.g., adjacent
the emission surface 22 of the beam expanding light pipe 14, so that light passes
through the prismatic diffuser 66 and is refracted.
The light expanding system 100 shown in Figure 6 includes the beam collector
28, the beam expanding light pipe 14 (first beam expanding light pipe) and a second
beam expanding light pipe 70 to convert divergent light from the light source 2 into a
planar light beam. The beam collector 28 and the first beam expanding light pipe 14
operate as described above. The light that exits the first beam expanding light pipe 14
from the emission surface 22 enters the second beam expanding light pipe 70 through
an entry surface 74 of the second beam expanding light pipe 70. Tai teaches (column
12, lines 56-61) that
the dimensions of the entry surface 74 are chosen to be at least as large as the
corresponding dimensions of the emission surface 22 of the first beam
expanding light pipe 14. This is done to avoid light leakage as light passes
between the first beam expanding light pipe 14 and the second beam expanding
light pipe 70.
A plurality of microprisms 72 are positioned adjacent to a reflecting surface 76. The
reflecting surface 76 is substantially perpendicular to the entry surface 74 of the second
beam expanding light pipe 70. The microprisms 72 direct the light so that the light exits
the second beam expanding light pipe 70 at an emission surface 78 that is opposite the
reflecting surface 76. An end surface 79 of the second beam expanding light pipe 70,
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Last modified: November 3, 2007