Imaging lens for infrared cameras
First Claim
Patent Images
1. An infrared imaging device, comprising:
- first and second plastic Fresnel lens elements in optical communication with each other;
wherein said first lens element has positive power and said second lens element also has positive power, and wherein said first lens element is adapted to mimic a meniscus asphere correct for conjugates of infinity and for the focal length of said first lens element.
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Abstract
An infrared imaging device is provided which comprises first and second plastic Fresnel lenses that are in optical communication with each other. Each of the first and second lenses have a first major surface which is convex and a second major surface which comprises a Fresnel surface. The first lens is adapted to mimic a meniscus asphere correct for conjugates of infinity and for the focal length of said first lens, and the second lens is adapted to mimic a meniscus asphere and is further adapted to act as a field flattener.
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Citations
27 Claims
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1. An infrared imaging device, comprising:
first and second plastic Fresnel lens elements in optical communication with each other;
wherein said first lens element has positive power and said second lens element also has positive power, and wherein said first lens element is adapted to mimic a meniscus asphere correct for conjugates of infinity and for the focal length of said first lens element.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. An infrared imaging device, comprising:
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first and second plastic Fresnel lens elements in optical communication with each other, wherein each of said first and second lens elements have positive power; a chassis which supports said first and second lens elements in a fixed orientation with respect to each other along a longitudinal axis; a mechanism adapted to adjust the distance between the first and second lens elements along the longitudinal axis; and a focal plane array detector; wherein said first lens element is adapted to mimic a meniscus asphere correct for conjugates of infinity and for the focal length of said first lens element. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. An infrared imaging device, comprising:
first and second plastic Fresnel lens elements in optical communication with each other;
wherein said first lens element has positive power and said second lens element also has positive power, and wherein said second lens element is adapted to mimic a meniscus asphere and is further adapted to act as a field flattener.
Specification