Appeal No. 1999-1647
Application 08/934,088
The Examiner states that Okamoto is applied to show that
the gate oxide thickness is varied to meet different design
requirements (EA7). Appellants argue that Okamoto is a memory
cell, not an image sensor (Br9). It is argued that Okamoto
shows the peripheral driver transistors having a thicker gate
insulating layer than the memory cell transistors, which is
opposite to the claimed arrangement, where the peripheral
drive transistors have a thinner gate insulating layer (Br9:
RBr4). The Examiner states that it is not understood how this
conclusion can be reached since there is no comparison between
phototransistors and driver transistors in Okamoto (EA7).
Okamoto does not disclose image sensor transistors and,
so, it is not helpful in establishing the specific fact at
issue: whether it was known for thin film transistors of the
image sensor type to have thicker gate insulating films than
thin film driver transistors. What is at issue is the
relative thicknesses of gate insulating films of
photo-sensitive TFTs and driving TFTs and the Examiner has not
cited any prior art evidence that would establish the
obviousness of this limitation. The fact that gate insulating
films of different devices can have different thicknesses does
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