INFRARED OBJECTIVE WITH VARIABLE FOCAL DISTANCE Russian patent published in 2009 - IPC G02B13/14 G02B9/60 G02B15/14 

FIELD: physics, optics.

SUBSTANCE: invention can be used in thermal imager optical systems, including, looking type with matrix receivers of an infrared range. The objective contains the first positive meniscus located on a course of beams and converted by an incurvation to a plane of images, the second biconcave lens, the third positive meniscus converted by an incurvation to a plane of images, and the fourth plus builder in the form of the subzero and positive meniscuses converted by protuberance to each other. The second and third lenses move in opposite directions, have two fixed standings and small motions in these standings. The relative optical forces of the components make, accordingly, (0.8÷0.9), - (3.0÷2.5), (2.0÷2.4) and (2.2÷2.8) and in an objective the relations specified in the formula of the invention are observed. All refracting surfaces in an objective are executed by the spherical.

EFFECT: increase of an angular aperture, an angular field, adaptability to manufacture, reduction of diameter of the first lens at maintenance of high quality of the image.

6 dwg