VARIABLE-FOCUS LENS Russian patent published in 1994 - IPC

FIELD: optical instrumentation engineering. SUBSTANCE: lens is provided in addition with fixed positive component placed between movable components; movable components of negative focal power are fixed together and mounted for displacement along optical axis obeying linear law, and focal length rations given in description of invention are taken in combination with shapes of lens components. Lens focal lengths are variable between 40 and 100 mm, relative aperture is 1:3:5, angular field of vision is 20 to 8 deg. EFFECT: reduced size of lens along with improved quality of picture throughout the entire field of vision, provision for displacement of movable components along optical axis obeying linear law. 1 dwg, 3 tbl