Patent US4636050A successfully refreshed from Google Patents.
US4636050A
Expired / Lapsed
US
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Reflection type overhead projector
Assignee: Gakushu Kenkyusha KK
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Filing: 1984-12-20
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Granted: 1987-01-13
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Expires: 2004-12-20
Abstract
Abstract A reflection type overhead projector employs a Fresnel concave mirror adapted for allowing a transparency to be put on the mirror surface thereof. The beam of light emitted from a light source lamp is reflected by the Fresnel concave mirror, enters a projecting lens and then is projected on a screen. A reflecting mirror is interposed in an optical path between the Fresnel concave mirror and the projecting lens to thereby bend the optical path. The Fresnel concave mirror, the light source lamp and the projecting lens are all mounted to a single case.
Inventors
- 👤 Susumu Tohata
- 👤 Kunio Numata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:41
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/132; G03B21/14; G03B21/30
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
214 words
A reflection type overhead projector comprising: a case having a Fresnel concave mirror disposed on a bottom wall thereof with a mirror surface facing upwardly for allowing a transparency to be placed thereon; light source means disposed at the front of said case; projecting lens means disposed at the front of said case; and reflecting mirror means disposed above said Fresnel concave mirror with a reflecting surface capable of facing downwardly and forwardly such that a light beam from said light source means is reflected by said reflecting mirror means into said Fresnel concave mirror and the reflected light beam from said Fresnel concave mirror is then reflected by said reflecting mirror means into said projecting lens means; wherein said case comprises a case body and a plate member forming at least a part of the top wall of said case and pivotably connected to said case body, said reflecting mirror is bonded to the lower surface of said plate member, the front end of said plate member is capable of being lifted up causing the mirror surface of said reflecting mirror to face downwardly forwardly when said projector is used, and a cut-out portion adapted for allowing the hand to be inserted therethrough is defined in the lateral side of said case body.
Claim 2
Dependent Claim
214 words
A reflection type overhead projector comprising: a case having a Fresnel concave mirror disposed on a bottom wall thereof with a mirror surface facing upwardly for allowing a transparency to be placed thereon; light source means disposed at the front of said case; projecting lens means disposed at the front of said case; and reflecting mirror means disposed above said Fresnel concave mirror with a reflecting surface capable of facing downwardly and forwardly such that a light beam from said light source means is reflected by said reflecting mirror means into said Fresnel concave mirror and the reflected light beam from said Fresnel concave mirror is then reflected by said reflecting mirror means into said projecting lens means; wherein said case comprises a case body and a plate member forming at least a part of the top wall of said case and pivotably connected to said case body, said reflecting mirror is bonded to the lower surface of said plate member, the front end of said plate member is capable of being lifted up causing the mirror surface of said reflecting mirror to face downwardly forwardly when said projector is used, and a cut-out portion adapted for allowing the hand to be inserted therethrough is defined in the lateral side of said case body.
Claim 3
Dependent Claim
33 words
A reflection type overhead projector according to claim 1, wherein a projector head comprising said light source means and said projecting lens means is rotatably connected to the front portion of said case.
Claim 4
Dependent Claim
49 words
A reflection type overhead projector according to claim 2, wherein said light source means includes a lamp box, a transversely slidable lamp carriage disposed in said lamp box, and a plurality of lamps provided on said lamp carriage side by side in the sliding direction of said lamp carriage.
Claim 5
Dependent Claim
70 words
A reflection type overhead projector according to claim 2, wherein said projecting lens means comprises a transversely slidable lens holder, and first and second projecting lenses provided on said lens holder side by side in the sliding direction of said lens holder, said first projecting lens being adapted to project a transparency put on and said Fresnel concave mirror, said second projecting lens being adapted to project a small-sized slide.
Claim 6
Dependent Claim
36 words
A reflection type overhead projector according to claim 4, wherein a slide holder for small-sized slides is provided in the rear of said second projecting lens, said slide holder being tiltable toward said second projecting lens.
Claim 7
Dependent Claim
201 words
A reflection type overhead projector comprising: a case having a Fresnel concave mirror disposed on a bottom wall thereof with a mirror surface facing upwardly for allowing a transparency to be placed thereon said case including a case body and a plate member forming at least a part of the top wall of said case and pivotally connected to said case body; light source means disposed at the front of said case; projecting lens means disposed at the front of said case, said projecting lens and said light source means being juxtaposed vertically; and reflecting mirror means secured to the lower surface of said plate member disposed above said Fresnel concave mirror with a reflecting surface capable of facing downwardly and forwardly where the front end of said plate member is capable of being lifted upwardly causing the reflecting surface of the reflecting mirror means to face downwardly and forwardly when the projector is in use so that a light beam from said light source means is reflected by said reflecting mirror means into said Fresnel concave mirror and the reflected light beam from said Fresnel concave mirror is then reflected by said reflecting mirror means into said projecting lens means.
Claim 8
Dependent Claim
201 words
A reflection type overhead projector comprising: a case having a Fresnel concave mirror disposed on a bottom wall thereof with a mirror surface facing upwardly for allowing a transparency to be placed thereon said case including a case body and a plate member forming at least a part of the top wall of said case and pivotally connected to said case body; light source means disposed at the front of said case; projecting lens means disposed at the front of said case, said projecting lens and said light source means being juxtaposed vertically; and reflecting mirror means secured to the lower surface of said plate member disposed above said Fresnel concave mirror with a reflecting surface capable of facing downwardly and forwardly where the front end of said plate member is capable of being lifted upwardly causing the reflecting surface of the reflecting mirror means to face downwardly and forwardly when the projector is in use so that a light beam from said light source means is reflected by said reflecting mirror means into said Fresnel concave mirror and the reflected light beam from said Fresnel concave mirror is then reflected by said reflecting mirror means into said projecting lens means.
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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) | 1990-01-12 | 1990-07-14 | 1991-01-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-01-12 | 1994-07-14 | 1995-01-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-01-12 | 1998-07-14 | 1999-01-13 | $7700.00 | Window Closed / Lapsed |