EP0051970A1
Expired / Lapsed
EP
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Optical system having a dual field of view
Assignee: Honeywell Inc
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Filing: 1981-11-03
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Granted: —
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Expires: 2001-11-03
Abstract
Abstract An optical system having a dual field of view includes a wide-angle objective (22) comprising a lens (23,24), a concave primary mirror (11), and a movable convex secondary mirror (12) having a first position and a second position. When in the first position, the secondary mirror permits the wide-angle objective to focus radiation. When in the second position, the secondary mirror prevents radiation from being focused by the wide-angle objective. The combination of the secondary mirror when in the second position and the primary mirror comprise a narrow-angle objective with the primary mirror converging radiation to the secondary mirror and the secondary mirror focusing radiation. Thus, the optical system has a wide-angle field of view whenever the secondary mirror is in the first position and a narrow-angle field of view whenever the secondary mirror is in the second position.
Inventors
- 👤 Irving R. Abel
- 👤 Marcus R. Hatch
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 07:30
CPC Classifications
G; G02; G02B; G02B17/00; G02B17/08; G02B17/0856; G02B17/0804; G02B17/0808; G02B17/0852; G02B17/0884; G02B17/0896
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
108 words
An optical system comprising a wide-angle objective comprising a lens; a concave primary mirror; a convex secondary mirror characterized in that the secondary mirror (12) is movable between a first position (Figure 2) and a second position (Figure 1), the secondary mirror when in the first position permitting the wide-angle objective (22) to focus radiation; the secondary mirror when in the second position preventing radiation from being focused by the wide-angle objective; the combination of the secondary mirror when in the second position and the primary mirror (11) comprising a narrow-angle objective with the primary mirror converging radiation to the secondary mirror and the secondary mirror focusing radiation.
Claim 2
Dependent Claim
108 words
An optical system comprising a wide-angle objective comprising a lens; a concave primary mirror; a convex secondary mirror characterized in that the secondary mirror (12) is movable between a first position (Figure 2) and a second position (Figure 1), the secondary mirror when in the first position permitting the wide-angle objective (22) to focus radiation; the secondary mirror when in the second position preventing radiation from being focused by the wide-angle objective; the combination of the secondary mirror when in the second position and the primary mirror (11) comprising a narrow-angle objective with the primary mirror converging radiation to the secondary mirror and the secondary mirror focusing radiation.
Claim 3
Dependent Claim
70 words
The optical system of Claim 1, characterized in that the convex secondary mirror (12) has a first and second surface (13,14), the second surface being coated with reflective material, the radiation received from the primary mirror being refracted at the first surface, reflected back from the second surface, and then refracted once again by the first surface, the configuration of the first and second surfaces providing control of field curvature.
Claim 4
Dependent Claim
71 words
The optical system of Claim 2, characterized in that the first and second surfaces each have radii which determine the field curvature by the equation 1/R = 2 [(n-1)/r 1 + 1/r 2 ]/n, where R is the radius of the field curvature, n is the index of refraction of the lens, r 1 is the radius of the first surface, and r 2 is the radius of the second surface.
Claim 5
Dependent Claim
71 words
The optical system of Claim 2 or 3, characterized in that the power of the secondary mirror is 1/f and is defined by the equation 1/f = 2[n/r 2 1 (n-1)r 1 ] where f is the focal length of the secondary mirror, n is the index of refraction of the lens, r 1 is the radius of the first surface, and r 2 is the radius of the second surface.
Claim 6
Dependent Claim
28 words
The optical system of any one of the preceding Claims, characterized in that the radiation is focused at the same location by both the wide-angle and narrow-angle objectives.
Claim 7
Dependent Claim
25 words
The optical system of any one of the preceding Claims, characterized in that one or both the primary mirror and the secondary mirrors are aspheric.
Claim 8
Dependent Claim
28 words
The optical system of any one of the preceding Claims, characterized in that the primary mirror has an aperture for transmission of radiation reflected from the secondary mirror.
Claim 9
Dependent Claim
25 words
The optical system of any one of the preceding Claims, characterized in that compactness of the narrow-angle objective measured by the ratio is approximately 0.3.
References Cited (Backward Citations)
GB1322333A
Cited
DE2720990A1
Cited
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