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US 2025/0147289 A1Published application
Infrared Objective Lens with Curved Focal Surface
AssigneeThe Government of the United States, as represented by the Secretary of the Army
InventorJohn M. Hall
Life of this patent
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Abstract
A low-cost objective lens design uses only ZnS optical material, suitable for use with an uncooled infrared bolometer having a curved focal plane. Its objective lens field of view is at least ±20.0° over a 1280×720 pixel array with 0.0012 mm pitch. Lens chromatic aberrations are corrected over at least the 8-11 micron infrared wavelength band. The objective lens operates at a relatively fast F #/1.0 which is common in the art for bolometer applications.
Claims20
An optical system, comprising:
- a first optical element based on a ZnS optical material having a diameter of at least 28 mm, wherein a first surface of the first optical element has an aspherical curvature to enable correction of higher order optical aberrations, and wherein a second surface of the first optical element has a hybridized surface profile of an aspheric base curvature with an overlaid diffractive pattern;
- a second lens element based on the ZnS optical material having a diameter of at least 30.5 mm, wherein a first surface of the second lens element has an aspherical curvature to enable correction of higher order optical aberrations, and wherein a second surface of the second lens element has a hybridized surface profile of an aspheric base curvature with an overlaid diffractive pattern;
- and
- a flat window disposed to have a first flat surface of the flat window face the second surface of the second lens element, wherein, an opposing flat surface of the flat window faces a curved focal plane, and wherein the curved focal plane is characterized by a concave radius of curvature of roughly 52.5 mm to obviate a need to correct field flatness aberrations.
1 more element
Dependencies are inferred from the claim text.