Objective comprising aspherical surfaces, whose focal length is variable over a wide range
Number of patents in Portfolio can not be more than 2000
United States of America Patent
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Nov 22, 1983
Grant Date -
N/A
app pub date -
Sep 29, 1980
filing date -
Sep 28, 1979
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
The objective comprises a plurality of movable lens components and at least one stationary lens component group, at least two of said components including an aspherical surface. The movable components are constituted by single lenses of which at least one lens comprises an aspherical surface, while the stationary lens component group(s) may comprise at least one aspherical surface. Steadiness of the image plane is obtained by mechanical compensation for focal-length variations with a ratio greater than five, which may readily reach the value eight. The aspherical lenses are arranged so that for the same focal length variation the total number of lenses of the objective, which may be spherical or non-spherical, is smaller than in any other variable-focus objective with a stationary image plane comprising solely spherical lenses: This results in a reduction of the mass of the objective, namely of the movable parts, and a reduction of the power necessary for moving said parts. Application to color television camera.
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Cited Art Landscape
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