Patent US4948213A successfully refreshed from Google Patents.
US4948213A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Beam scanner
Assignee: Fujitsu Ltd
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Filing: 1989-03-27
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Granted: 1990-08-14
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Expires: 2009-03-27
Abstract
Abstract A light beam scanning apparatus includes a rotatable holographic disk having a hologram which is constructed by an interference of a reference wave and an objective wave, which is a coma wave, the coma wave having a focal length which decreases toward the outer periphery from the inner periphery of the holographic disk in a radial direction. The focal length has a different direction perpendicular to the radial direction, so that when the hologram of the holographic disk which rotates is reconstructed by a reconstruction wave, the scanning is effected by the beams diffracted by the hologram.
Inventors
- 👤 Shin-ya Hasegawa
- 👤 Fumio Yamagishi
- 👤 Hiroyuki Ikeda
- 👤 Shigetake Iwata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 14:14
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
108 words
A light beam scanning apparatus comprising: a rotatable holographic disk having a hologram for diffracting beams and being constructed by an interference of construction waves including a reference wave and an objective wave, at least one of the construction waves being a coma wave, said coma wave having a focal length which decreases toward the outer periphery from the inner periphery of the holographic disk in a radial direction, said focal length having a different direction perpendicular to the radial direction, so that when the hologram of the holographic disk, which rotates, is reconstructed by a reconstruction wave scanning is effected by the beams diffracted by the hologram.
Claim 2
Dependent Claim
108 words
A light beam scanning apparatus comprising: a rotatable holographic disk having a hologram for diffracting beams and being constructed by an interference of construction waves including a reference wave and an objective wave, at least one of the construction waves being a coma wave, said coma wave having a focal length which decreases toward the outer periphery from the inner periphery of the holographic disk in a radial direction, said focal length having a different direction perpendicular to the radial direction, so that when the hologram of the holographic disk, which rotates, is reconstructed by a reconstruction wave scanning is effected by the beams diffracted by the hologram.
Claim 3
Dependent Claim
34 words
A light beam scanning apparatus according to claim 1, wherein said objective wave is a coma wave which is produced when a non-aberration spherical wave incident upon a spherical optical element is axially offset.
Claim 4
Dependent Claim
18 words
A light beam scanning apparatus according to claim 2, wherein said spherical optical element is a convex lens.
Claim 5
Dependent Claim
20 words
A light beam scanning apparatus according to claim 3, wherein said reference wave is divergent spherical wave having no aberration.
Claim 6
Dependent Claim
41 words
A light beam scanning apparatus according to claim 3, wherein said reference wave is emitted from a point light source located opposite to a point light source of the objective wave with respect to an axis of the rotatable holographic disk.
Claim 7
Dependent Claim
56 words
A light beam scanning apparatus according to claim 5, wherein a normal distance between the point light source of the object wave and the holographic disk is given by the following equation: F.sub.2 =√(S.sup.2 -1)Y.sub.2 (Y.sub.2 -R) wherein Y 2 is a distance between the point light sources of the reference wave and the objective wave.
Claim 8
Dependent Claim
34 words
A light beam scanning apparatus according to claim 1, wherein said reference wave is a coma wave which is produced when a non-aberration spherical wave incident upon a spherical optical element is axially offset.
Claim 9
Dependent Claim
18 words
A light beam scanning apparatus according to claim 7, wherein said spherical optical element is a convex lens.
Claim 10
Dependent Claim
27 words
A light beam scanning apparatus according to claim 1, wherein the wavelength of the construction waves of the hologram is shorter than that of the reconstruction wave.
Claim 11
Dependent Claim
164 words
A light beam scanning apparatus according to claim 1, wherein both the reference wave and the objective wave are divergent spherical waves emitted from point light sources and wherein the reconstruction wave is incident upon the holographic disk at a reconstruction point at an incident angle θ i given by the following equation: R/l·cos θ.sub.d =cos θ.sub.i -cos θ.sub.d . . . sin θ.sub.i =S·R/√(F.sub.1 .sup.2 +R.sup.2) wherein R is a distance between the axis of rotation of the holographic disk and the reconstruction point; l is a focal length of the hologram; θ i is a incident angle of the reconstruction wave; θ d is a diffraction angle of the reconstruction wave by the hologram; S is a ratio between the wavelength (λ 1 ) of the construction wave and the wavelength (λ 2 ) of the construction wave (S=λ 2 /λ 1 ); F 1 is a normal distance between the point light source of the reference wave and the holographic disk.
Claim 12
Dependent Claim
186 words
A light beam scanning apparatus comprising: a rotatable holographic disk having a hologram for diffracting beams and being constructed by an interference of a reference wave and an objective wave wherein both the reference wave and the objective wave are divergent spherical waves emitted from point light sources and wherein the reconstruction wave is incident upon the holographic disk at a reconstruction point at an incident angle θ i given by the following equation: R/l cos θ.sub.d =cos θ.sub.i -cos θ.sub.d . . . sin θ.sub.i =S·R/√(F.sub.1 .sup.2 +R.sup.2) wherein R is a distance between the axis of rotation of the holographic disk and the reconstruction point; l is a focal length of the hologram; θ i is an incident angle of the reconstruction wave; θ d is a diffraction angle of the reconstruction wave by the hologram; S is a ratio between the wavelength (λ 1 ) of the construction wave and the wavelength (λ 2 ) of the construction wave (S=λ 2 /λ 1 ); F 1 is a normal distance between the point light source of the reference wave and the holographic disk.
Claim 13
Dependent Claim
186 words
A light beam scanning apparatus comprising: a rotatable holographic disk having a hologram for diffracting beams and being constructed by an interference of a reference wave and an objective wave wherein both the reference wave and the objective wave are divergent spherical waves emitted from point light sources and wherein the reconstruction wave is incident upon the holographic disk at a reconstruction point at an incident angle θ i given by the following equation: R/l cos θ.sub.d =cos θ.sub.i -cos θ.sub.d . . . sin θ.sub.i =S·R/√(F.sub.1 .sup.2 +R.sup.2) wherein R is a distance between the axis of rotation of the holographic disk and the reconstruction point; l is a focal length of the hologram; θ i is an incident angle of the reconstruction wave; θ d is a diffraction angle of the reconstruction wave by the hologram; S is a ratio between the wavelength (λ 1 ) of the construction wave and the wavelength (λ 2 ) of the construction wave (S=λ 2 /λ 1 ); F 1 is a normal distance between the point light source of the reference wave and the holographic disk.
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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) | 1993-08-13 | 1994-02-12 | 1994-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-08-13 | 1998-02-12 | 1998-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-08-13 | 2002-02-12 | 2002-08-14 | $7700.00 | Window Closed / Lapsed |