US5046838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Illumination system for use in image projection apparatus
Assignee: Minolta Co Ltd
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Filing: 1990-03-15
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Granted: 1991-09-10
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Expires: 2010-03-15
Abstract
Abstract An illumination system for use in an image projection apparatus, having a light source assembly which includes a lamp and a concave reflector for producing convergent light, and an illumination lens group which includes, in order from the light source assembly side, a first lens unit of a negative power, a second lens unit of a positive power movable along the optical axis and a third lens unit of a positive power. The illumination lens group fulfills the following equation, 1+2<0 where 1 and 2 represent the powers of said first and second lens units, respectively.
Inventors
- 👤 Satoshi Iwasaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 19:32
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/14; G03B21/20; G02; G02B; G02B19/00; G02B19/0004; G02B19/0028; G02B19/0033; G02B19/0047
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
143 words
An illumination system for use in an image projection apparatus, the illumination system being compact and illuminating an original which retains an image to be projected, the image projection apparatus having a projection lens unit in an exchangeable manner to project the image of said original onto an image receiving plane with a different magnification, the illumination system comprising: a light source assembly which emits convergent light to illuminate the original; and an illumination lens group including, as arranged from the light source assembly side, a first lens unit of a negative power, a second lens unit of a positive power which is movable along the optical axis and a third lens unit of a positive power, wherein the illumination lens group fulfills the following equation, φ1+ φ2<0 where φ1 and φ2 represent the powers of said first and second lens units, respectively.
Claim 2
Dependent Claim
143 words
An illumination system for use in an image projection apparatus, the illumination system being compact and illuminating an original which retains an image to be projected, the image projection apparatus having a projection lens unit in an exchangeable manner to project the image of said original onto an image receiving plane with a different magnification, the illumination system comprising: a light source assembly which emits convergent light to illuminate the original; and an illumination lens group including, as arranged from the light source assembly side, a first lens unit of a negative power, a second lens unit of a positive power which is movable along the optical axis and a third lens unit of a positive power, wherein the illumination lens group fulfills the following equation, φ1+ φ2<0 where φ1 and φ2 represent the powers of said first and second lens units, respectively.
Claim 3
Dependent Claim
23 words
An illumination system as claimed in claim 1, wherein said light source assembly comprises a lamp and a concave reflector behind the lamp.
Claim 4
Dependent Claim
17 words
An illumination system as claimed in claim 1, wherein said third lens unit comprises a Fresnel lens.
Claim 5
Dependent Claim
24 words
An illumination system as claimed in claim 1, wherein at least one of said first and second lens units is made of heat-absorbing glass.
Claim 6
Dependent Claim
142 words
An illumination system for use in an image projection apparatus, comprising: a light source assembly which emits convergent light; a first lens unit of a negative power which is located in the vicinity of said light source assembly; a second lens unit of a negative power which is located in the vicinity of said light source assembly; a second lens unit of a positive power which is positioned at the side opposite to said light source assembly with respect to said first lens unit and movable along the optical axis; and a third lens unit of a positive power which is located at the side opposite to said first lens unit with respect to said second lens unit; wherein the illumination systems fulfills the following equation, φ1+φ2<0 where φ1 and φ2 represent the powers of said first and second lens units, respectively.
Claim 7
Dependent Claim
142 words
An illumination system for use in an image projection apparatus, comprising: a light source assembly which emits convergent light; a first lens unit of a negative power which is located in the vicinity of said light source assembly; a second lens unit of a negative power which is located in the vicinity of said light source assembly; a second lens unit of a positive power which is positioned at the side opposite to said light source assembly with respect to said first lens unit and movable along the optical axis; and a third lens unit of a positive power which is located at the side opposite to said first lens unit with respect to said second lens unit; wherein the illumination systems fulfills the following equation, φ1+φ2<0 where φ1 and φ2 represent the powers of said first and second lens units, respectively.
Claim 8
Dependent Claim
23 words
An illumination system as claimed in claim 5, wherein said light source assembly comprises a lamp and a concave reflector behind the lamp.
Claim 9
Dependent Claim
17 words
An illumination system as claimed in claim 5, wherein said third lens unit comprises a Fresnel lens.
Claim 10
Dependent Claim
24 words
An illumination system as claimed in claim 5, wherein at least one of said first and second lens units is made of heat-adsorbing glass.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-09-09 | 1995-03-11 | 1995-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-09-09 | 1999-03-11 | 1999-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-09-09 | 2003-03-11 | 2003-09-10 | $7700.00 | Window Closed / Lapsed |