US3762809A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Original mount or holder for optical projection system
Assignee: Ricoh Co Ltd
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Filing: 1970-12-30
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Granted: 1973-10-02
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Expires: 1990-12-30
Abstract
Abstract An original mount or holder for an overhead projector is provided in which a transparent original is formed or placed upon the flat surface of a Fresnal lens and a light reflecting surface or coating is formed either upon the stepped surface of the Fresnel lens opposite to the flat surface where the transparent original is formed or on the surface of the transparent original not engaging the Fresnel lens. An image of the original may be projected upon a screen by a projection lens which directs light beams that have been reflected by the reflecting surface or coating and passed undiffracted through the flat interface between the transparent original and the Fresnel lens achieving a sharper, brighter image.
Inventors
- 👤 S Kato
- 👤 H Sawada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:57
CPC Classifications
G; G03; G03B; G03B21/00; G03B21/132; Y; Y10; Y10S; Y10S353/00; Y10S353/04; Y10S353/05
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
141 words
An original mount for use in a reflection type optical projection system of the type having a light source for projecting light onto an original and a projection lens for focusing the light reflected therefrom, said mount comprising the combination of: a. a Fresnel lens having a flat surface and a stepped surface; b. a transparent original containing the information to be projected, and having two opposed flat surfaces, one of said flat surfaces disposed in engagement with the flat surface of said Fresnel lens; and c. a light reflecting surface disposed on the non-engaging surface of said transparent original such that light from said source reflected by said reflecting surface will be transmitted undiffracted through the interface formed by the engagement of the flat surfaces of said transparent original and said Fresnel lens before being projected by said projection lens.
Claim 2
Dependent Claim
141 words
An original mount for use in a reflection type optical projection system of the type having a light source for projecting light onto an original and a projection lens for focusing the light reflected therefrom, said mount comprising the combination of: a. a Fresnel lens having a flat surface and a stepped surface; b. a transparent original containing the information to be projected, and having two opposed flat surfaces, one of said flat surfaces disposed in engagement with the flat surface of said Fresnel lens; and c. a light reflecting surface disposed on the non-engaging surface of said transparent original such that light from said source reflected by said reflecting surface will be transmitted undiffracted through the interface formed by the engagement of the flat surfaces of said transparent original and said Fresnel lens before being projected by said projection lens.
Claim 3
Dependent Claim
27 words
An original mount as in claim 1 wherein said original mount includes a recording surface on the opposite side of said reflecting surface from said light source.
Claim 4
Dependent Claim
17 words
An original mount as in claim 2 wherein said recording surface is adapted to receive written information.
Claim 5
Dependent Claim
16 words
An original mount as in claim 2 wherein said recording surface is adapted for magnetic recording.
Claim 6
Dependent Claim
173 words
An original mount for use in a reflection type optical projection system of the type having a light source for projecting light onto an original and a projection lens for focussing the light reflected therefrom, said mount comprising the combination of: a. two Fresnel lenses, each having a flat surface and a stepped surface; b. two transparent originals containing information to be projected, and each having two opposed flat surfaces, one of said flat surfaces disposed respectively in engagement with the flat surface of one of said Fresnel lenses; and c. light reflecting surfaces disposed on said stepped surfaces of said Fresnel lenses with the rear surfaces of the two reflecting surfaces disposed in back-to-back relation such that the transparent originals are formed upon the outwardly diposed flat surfaces of said Fresnel lenses and light from said source reflected by said reflecting surfaces will be transmitted undiffracted through the interface formed by the engagement of the flat surfaces of said transparent originals and said Fresnel lenses before being projected by said projection lens.
Claim 7
Dependent Claim
173 words
An original mount for use in a reflection type optical projection system of the type having a light source for projecting light onto an original and a projection lens for focussing the light reflected therefrom, said mount comprising the combination of: a. two Fresnel lenses, each having a flat surface and a stepped surface; b. two transparent originals containing information to be projected, and each having two opposed flat surfaces, one of said flat surfaces disposed respectively in engagement with the flat surface of one of said Fresnel lenses; and c. light reflecting surfaces disposed on said stepped surfaces of said Fresnel lenses with the rear surfaces of the two reflecting surfaces disposed in back-to-back relation such that the transparent originals are formed upon the outwardly diposed flat surfaces of said Fresnel lenses and light from said source reflected by said reflecting surfaces will be transmitted undiffracted through the interface formed by the engagement of the flat surfaces of said transparent originals and said Fresnel lenses before being projected by said projection lens.
Claim 8
Dependent Claim
45 words
An original mount as in claim 5 wherein the front surfaces of the two reflecting surfaces on the stepped surfaces of said two Fresnel lenses are alternately disposed such that the respective surfaces are interfitted when the two Fresnel lenses are placed in back-to-back relationship.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-10-01 | 1977-04-02 | 1977-10-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-10-01 | 1981-04-02 | 1981-10-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-10-01 | 1985-04-02 | 1985-10-02 | $7700.00 | Window Closed / Lapsed |