PYTHON25K Datasheet, PDF (8/87 Pages) ON Semiconductor – PYTHON 25K/16K/12K/10K Global Shutter CMOS Image Sensors

NOIP1SN025KA, NOIP1SN016KA, NOIP1SN012KA, NOIP1SN010KA
Ray Angle and Microlens Array Information
An array of microlenses is placed over the CMOS pixel
array in order to improve the absolute responsivity of the
photodiodes. The combined microlens array and pixel array
has two important properties:
1. Angular dependency of photoresponse of a pixel
The photoresponse of a pixel with microlens in
the center of the array to a fixed optical power
with varied incidence angle is as plotted in
Figure 5, where definitions of angles fx and fy
are as described by Figure 6.
2. Microlens shift across array and CRA
The microlens array is fabricated with a slightly
smaller pitch than the array of photodiodes. This
difference in pitch creates a varying degree of shift
of a pixel’s microlens with regards to its
photodiode. A shift in microlens position versus
photodiode position will cause a tilted angle of
peak photoresponse, here denoted Chief Ray
Angle (CRA). Microlenses and photodiodes are
aligned with 0 shift and CRA in the center of the
array, while the shift and CRA increases radially
towards its edges, as illustrated by Figure 7.
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