US4632499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Light beam scanning apparatus
Assignee: Fujifilm Holdings Corp
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Filing: 1983-12-09
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Granted: 1986-12-30
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Expires: 2003-12-09
Abstract
Abstract A light beam scanning apparatus comprises a rotatable plate provided with at least one plane diffraction grating, and a light beam source for emitting a light beam incident on the plane diffraction grating so that the plane of incidence is a plane in which the rotation axis of the rotatable plate lies. The light beam diffracted by the plane diffraction grating is reflected at least by use of a plane reflection surface normal to the plane of incidence, and guided again to the plane diffraction grating. The light beam diffracted again by the plane diffraction grating is focused by a focusing lens onto a scanning surface, whereby a bow-free scan line is formed on the scanning surface as the rotatable plate is rotated.
Inventors
- 👤 Masaru Noguchi
- 👤 Hiromi Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:38
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
241 words
A light beam scanning apparatus comprising: a rotatable plate provided with at least one plane diffraction grating; a light beam source for emitting a light beam incident on one of said plane diffraction gratings so that the plane of incidence is a plane in which the rotation axis of said rotatable plate lies; an optical system for reflecting the light beam diffracted by said one plane diffraction grating comprising a plane reflection surface normal to said plane of incidence for reflecting and guiding said light beam again to said plane diffraction grating; and a focusing lens for focusing the light beam diffracted again by said one plane diffraction grating onto a scanning surface; whereby said scanning surface is scanned with the focused light spot as said rotatable plate is rotated and; wherein said light beam source emits a light beam having a wavelength of approxiamtely one-half of a grating period of said plane diffraction grating and an angle of incidence on said plane diffraction grating of 0°, and said optical system for reflecting and guiding said light beam again to said plane diffraction grating is arranged to reflect the light beam diffracted by said plane diffraction grating and guide said light beam again to said plane diffraction grating so that the component of said guide light beam projected on said plane of incidence is antiparallel with respect to the component of said diffracted light beam projected on said plane of incidence.
Claim 2
Dependent Claim
241 words
A light beam scanning apparatus comprising: a rotatable plate provided with at least one plane diffraction grating; a light beam source for emitting a light beam incident on one of said plane diffraction gratings so that the plane of incidence is a plane in which the rotation axis of said rotatable plate lies; an optical system for reflecting the light beam diffracted by said one plane diffraction grating comprising a plane reflection surface normal to said plane of incidence for reflecting and guiding said light beam again to said plane diffraction grating; and a focusing lens for focusing the light beam diffracted again by said one plane diffraction grating onto a scanning surface; whereby said scanning surface is scanned with the focused light spot as said rotatable plate is rotated and; wherein said light beam source emits a light beam having a wavelength of approxiamtely one-half of a grating period of said plane diffraction grating and an angle of incidence on said plane diffraction grating of 0°, and said optical system for reflecting and guiding said light beam again to said plane diffraction grating is arranged to reflect the light beam diffracted by said plane diffraction grating and guide said light beam again to said plane diffraction grating so that the component of said guide light beam projected on said plane of incidence is antiparallel with respect to the component of said diffracted light beam projected on said plane of incidence.
Claim 3
Dependent Claim
26 words
An apparatus as defined in claim 1 wherein the grating lines of said plane diffraction grating are tangent to the rotating direction of said rotatable plate.
Claim 4
Dependent Claim
29 words
An apparatus as defined in claim 1 wherein said optical system for reflecting and guiding said light beam again to said plane diffraction grating comprises two plane reflection surfaces.
Claim 5
Dependent Claim
19 words
An apparatus as defined in claim 3 wherein said two plane reflection surfaces are positioned perpendicularly to each other.
Claim 6
Dependent Claim
27 words
An apparatus as defined in claim 1, wherein said at least one plane diffraction grating is entirely disposed on one side of a diameter of said plate.
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) | 1989-12-29 | 1990-06-30 | 1990-12-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-12-29 | 1994-06-30 | 1994-12-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-12-29 | 1998-06-30 | 1998-12-30 | $7700.00 | Window Closed / Lapsed |