| CMOS Camera Lens |
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The design of CMOS camera lenses continues to be of some interest due to the inclusion of small, wide-angle lenses in cell phones and the desire to make them smaller and more cheaply. SMA's CMOS lens is an F/2.7 design with a 50 degree field of view. While not truly telecentric, the chief ray never strikes the sensor at an angle greater than about 16 degrees. MTF is very uniform across the entire 5mm diagonal field, and is between 70% and 80% at 50 cpmm, and approximately 50% at 87 cpmm. Lateral color is less than 2.5 microns, and distortion is less than 3%. Electronic gain compensation is usually necessary in these lenses due to illumination rolloff. The illumination in this lens is maintained above 80% out of 75% of the field, but then rolls off rather rapidly to approximatley 50% in the corners. The CMOS imaging lens is 7.6mm from the front vertex to the image plane, has a barrel diameter of approximately 6mm, and is completely plastic for low cost and very high volume.
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