US5619381A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Offset zoom lens for reflective light modulators
Assignee: Texas Instruments Inc
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Filing: 1995-06-02
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Granted: 1997-04-08
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Expires: 2015-06-02
Abstract
Abstract A projection optical system. The system (10) contains two movable lens groups, a zoom lens group (20) and a compensator group (18). The compensator group (18) includes a movable aperture stop (21), thereby eliminating the need for a variable aperture stop. Both groups contain at least one aspheric lens element (22, 32) for elimination of aberrations. The compensator group has a positive power, with the zoom group having a negative power, resulting in a reverse telephoto configuration.
Inventors
- 👤 Doug Anderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:28
CPC Classifications
G; G02; G02B; G02B13/00; G02B13/04
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
94 words
An optical system with variable magnification, comprising: a zoom lens group including at least one aspheric lens, said zoom lens group having negative optical power and being movable; a compensator lens group having positive optical power and being movable, said compensator group including: at least one aspheric lens element; and at least two other lens elements, wherein said at least two other lens elements are fixed together to minimize chromatic aberrations in said system; and a aperture stop located with said compensator group and which moves with said compensator group thereby allowing constant brightness.
Claim 2
Dependent Claim
94 words
An optical system with variable magnification, comprising: a zoom lens group including at least one aspheric lens, said zoom lens group having negative optical power and being movable; a compensator lens group having positive optical power and being movable, said compensator group including: at least one aspheric lens element; and at least two other lens elements, wherein said at least two other lens elements are fixed together to minimize chromatic aberrations in said system; and a aperture stop located with said compensator group and which moves with said compensator group thereby allowing constant brightness.
Claim 3
Dependent Claim
14 words
The optical system of claim 1, wherein said zoom lens group comprises four lenses.
Claim 4
Dependent Claim
13 words
The optical system of claim 1, wherein said compensator group comprises four lenses.
Claim 5
Dependent Claim
22 words
The optical system of claim 3 wherein said aperture stop is located between the third and fourth element of said compensator group.
Claim 6
Dependent Claim
19 words
The optical system of claim 1, wherein said aspheric lens included in said zoom group includes a diffractive component.
Claim 7
Dependent Claim
19 words
The optical system of claim 1 wherein said aspheric lens included in said compensator group includes a diffractive component.
Claim 8
Dependent Claim
123 words
An optical system with variable magnification comprising: a zoom lens group which has negative power and is movable, including: first and second lens elements of negative power; a third lens element wherein said third lens element is aspheric and has negative power; and a fourth lens element having a positive power; a compensator lens group which has positive power and is movable, including: first and second lens elements of positive power; a third lens element of negative power which is fixed to said second lens element; and a fourth lens element which has positive power; and an aperture stop located between said third lens element and said fourth lens element of said compensator group, said aperture stop being movable with said compensator group.
Claim 9
Dependent Claim
123 words
An optical system with variable magnification comprising: a zoom lens group which has negative power and is movable, including: first and second lens elements of negative power; a third lens element wherein said third lens element is aspheric and has negative power; and a fourth lens element having a positive power; a compensator lens group which has positive power and is movable, including: first and second lens elements of positive power; a third lens element of negative power which is fixed to said second lens element; and a fourth lens element which has positive power; and an aperture stop located between said third lens element and said fourth lens element of said compensator group, said aperture stop being movable with said compensator group.
References Cited (Backward Citations)
US4159865A
Cited
US5268790A
Cited
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