Patent US4325601A successfully refreshed from Google Patents.
US4325601A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical scanning device
Assignee: Ricoh Co Ltd
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Filing: 1980-03-03
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Granted: 1982-04-20
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Expires: 2000-03-03
Abstract
Abstract An optical scanning device shifting an optical spot on the scanning surface by rotating a hologram record medium on which a hologram is recorded, is so improved that, in recording a hologram, the incident angle of the principal ray of an object light and the incident angle of the principal ray of a reference light are so defined as to satisfy a particular condition, whereby even if the hologram record is inclined, the optical spot is not displaced.
Inventors
- 👤 Hiroyoshi Funato
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 20:48
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
155 words
An optical scanning device comprising: a hologram recording medium having a photo sensitive hologram surface which is rotatable about an axis; a scanning surface adjacent said hologram recording medium; first light source means for directing a principal ray of an object light onto said hologram surface at an angle α with respect to a plane normal to said hologram surface; and second light source means for directing a principal ray of a reference light onto said hologram surface at an angle β with respect to a plane normal to said hologram surface, wherein angles α and β are selected such that: cos β=cos α(1+(r/f) cos.sup.2 α) where: r=distance between said axis and said hologram surface f=distance between said scanning surface and said hologram surface, whereby a shift in the position of a spot of said principal ray of said object light on said scanning surface in response to a shift of said axis is minimized.
Claim 2
Dependent Claim
155 words
An optical scanning device comprising: a hologram recording medium having a photo sensitive hologram surface which is rotatable about an axis; a scanning surface adjacent said hologram recording medium; first light source means for directing a principal ray of an object light onto said hologram surface at an angle α with respect to a plane normal to said hologram surface; and second light source means for directing a principal ray of a reference light onto said hologram surface at an angle β with respect to a plane normal to said hologram surface, wherein angles α and β are selected such that: cos β=cos α(1+(r/f) cos.sup.2 α) where: r=distance between said axis and said hologram surface f=distance between said scanning surface and said hologram surface, whereby a shift in the position of a spot of said principal ray of said object light on said scanning surface in response to a shift of said axis is minimized.
Claim 3
Dependent Claim
17 words
An optical scanning device as claimed in claim 1 wherein said hologram record medium is conical 1.
Claim 4
Dependent Claim
18 words
An optical scanning device as claimed in claim 1 wherein said hologram record medium is concave or convex.
Claim 5
Dependent Claim
16 words
An optical scanning device as claimed in claim 1 wherein said hologram record medium is disc-shaped.
Claim 6
Dependent Claim
16 words
An optical scanning device as claimed in claim 1 wherein said hologram record medium is drum-shaped.
Claim 7
Dependent Claim
16 words
An optical scanning device as claimed in claim 1 wherein said hologram record medium is light-transmissive.
Claim 8
Dependent Claim
16 words
An optical scanning device as claimed in claim 1 wherein said hologram record medium is light-reflective.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-04-19 | 1985-10-19 | 1986-04-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-04-19 | 1989-10-19 | 1990-04-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-04-19 | 1993-10-19 | 1994-04-20 | $7700.00 | Window Closed / Lapsed |