Open AccessHANDHELD THERMAL VISION DEVICES WITH VARIABLE CHARACTERISTICS
Author(s) -
Т. Н. Хацевич,
Evgeniy V. Druzhkin,
Ksenia D. Volkova
Publication year - 2020
Publication title -
vestnik sgugit
Language(s) - English
Resource type - Journals
ISSN - 2411-1759
DOI - 10.33764/2411-1759-2020-25-4-213-220
Subject(s) - focal length , lens (geology) , optics , aperture (computer memory) , microbolometer , optical power , optical axis , component (thermodynamics) , cardinal point , realization (probability) , materials science , physics , bolometer , acoustics , mathematics , detector , laser , statistics , thermodynamics
The intensive development of thermal imaging device is accompanied by the expansion of its functional possibilities. One of them is the realization of changing magnifications and fields. The aim of the work is to justify the method of changing focal lengths and fields, ensuring the constancy of the relative aperture and axial length of the lenses when changing the field in thermal imaging devices using uncooled microbolometer infrared sensor arrays. A method of structural synthesis of a lens of three components is proposed. The method is characterized by the following: the optical power of the first component is equal to the optical power of the lens, the sum of the optical powers of the second and third components is zero. The aperture diaphragm is located on the third component. The internal component has two discrete positions. Relations between the parameters of components that are found provide the invariability of the back focal length and the relative aperture of the lens when changing the focal length. The capabilities of the method are confirmed by the development of four infrared lenses with two- and three-fold differences in focal lengths. Decreasing the length along the axis and the stability of the relative aperture of the lens with diffractive image qual-ity when changing the focal length in an optical scheme with a bi-aspheric design is achieved.