INFRARED LENS WITH TEMPERATURE COMPENSATION OF FOCUSING Russian patent published in 2017 - IPC G02B7/02 

FIELD: physics.

SUBSTANCE: lens comprises three lenses, the third of which has a rim and is mounted to be movable along the optical axis, and a temperature compensation unit including a compensation element made of a material with a coefficient of linear expansion substantially different from the housing material, installed parallel to the optical axis and resiliently pressed against the frame with one end, and the other end is rigidly fixed to the rim of the second lens. Between the housing and the photodetector parallel to the optical axis there is the second compensation element consisting of two parts, the first of which is made of a material with a coefficient of linear expansion substantially different from the housing material, and the second part is made of a material with the coefficient of linear expansion equal to the housing material. The second compensation element with one end is elastically pressed to the frame of the photodetector, and the other one - to the lens housing.

EFFECT: increasing the value of the possible movement of the lens with the frame during defocusing and the possibility of adjusting the position of the plane of the best installation in the presence of a spread in the coefficient of linear expansion of the material, from which the compensation elements are made.

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