Appeal No. 2006-1049
Application No. 09/667,826
33. A sample and hold capacitor 212 is then charged to the sample value
of the microbolometer voltage VD. This held voltage is then provided as the output
of the readout cell indicated as Vout on line 214 in FIG. 3A (col. 12, lines 55-59).
34. Referring to FIG. 3B, the readout cell 100 is illustrated employing
offset correction circuitry for compensating for nonuniformities in the detector
elements in the array of FIG. 2. The readout circuitry of FIG. 3B common to that
of FIG. 3A operates in the manner described above and a detected voltage VD is
provided at node 210 as described above (col. 12, lines 60-65).
35. Applicants state that voltage VD will vary from pixel to pixel even for
a uniform scene and uniform IR input to all the microbolometer elements 200 due
to inherent nonuniformities in processing of the microbolometer array (col. 12,
line 66 through col. 13, line 2).
36. In the present invention, such nonuniformities are compensated for by
offset correction circuit 220 which is coupled to node 222 and causes a suitable
amount of charge to be subtracted from (or added to) sample and hold capacitor
212 such that an offset corrected output voltage Vout is provided. That is, the offset
correction circuit 220 provides a corrected output voltage Vout at node 222 (col. 13,
lines 2-8).
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