Infrared objective lens systems
An infrared objective lens system comprises a primary lens group air spaced from a secondary lens group by means of a support assembly. The primary lens group and secondary lens group are aligned on a common optical axis and are arranged to form a real image at an external image surface from infrared radiation entering the system through a pupil in object space. Primary lens group is self-compensated for chromatic aberrations, is positively powered and is made of material the refractive index of which is relatively temperature insensitive such as arsenic triselenide and/or zinc selenide. The secondary lens group is positively powered, introduces minimal chromatic aberrations and is formed by a positively powered lens and a negatively powered lens. Lens is made of material the refractive index of which is relatively temperature insensitive such as arsenic triselenide. Lens is made of a material the refractive index of which is relatively temperature sensitive such as germanium and the thermal aberration introduced by lens is arranged to compensate for thermal aberrations introduced by the primary lens group and secondary lens group caused by thermal expansion of the support assembly as a result of which the system is rendered substantially passively athermal.
- Assignee:
- Barr and Stroud Limited
- Patent Number(s):
- US 4505535
- OSTI ID:
- 5441560
- Country of Publication:
- United States
- Language:
- English
Similar Records
Compact, high cold shield efficiency optical system
Miniature hybrid optical imaging lens
Related Subjects
47 OTHER INSTRUMENTATION
ARSENIC COMPOUNDS
ARSENIC SELENIDES
CHALCOGENIDES
ELECTROMAGNETIC RADIATION
ELEMENTS
FOCUSING
GERMANIUM
IMAGE TUBES
INFRARED RADIATION
LENSES
MEASURING INSTRUMENTS
METALS
OPTICS
PHYSICAL PROPERTIES
RADIATION DETECTORS
RADIATIONS
SELENIDES
SELENIUM COMPOUNDS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
ZINC COMPOUNDS
ZINC SELENIDES