Interference No. 104,649
Page No. 7
(Zhou '858, Fig. 3).
F14. Zhou describes Figure 3 as follows:
A finger is placed on the sensing surface 102, which is parallel to the X-axis. An
extended light source 202 provides the illumination radiation for the sheet prism
100. The illumination angle 208, which is the angle between the illumination
radiation and the Y-axis, is such that the radiation reaching the sensing surface
102 has an incident angle larger than the critical angle of the material of the sheet
prism 100 and less than 90 degrees. This ensures the incident radiation is being
total internally reflected at the sensing surface 102 at locations without the finger
ridges. Thus, a portion of the illumination radiation entering a number of the
entrance surfaces and incident at the sensing surface 102 is reflected through total
internal reflection. The reflected radiation emits from a number of the exit
surfaces to create the fingerprint image. Note that the sheet prism attenuates the
radiation, but the loss is lower than the bulky single prism because the sheet prism
is much thinner.
(Zhou '858, col. 3, lines 51-67). According to Zhou, the emitted radiation is focused by a lens
204 onto a detector array 206. (Zhou '858, col. 4, lines 12-13).'
6. Keagy et al., U.S. Application 09/255,744
Keagy Claim I
F 15. Keagy's claim I is identical to Zhou claim 1, which is also Count 1. Keagy claim I is an
originally filed claim for the '744 application.
'In Figure 3, the number "200" is said to represent a first embodiment of Zhou's
invention. (Zhou '858, col. 3, lines 49-50).
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Last modified: November 3, 2007