Patent EP0214018A2 successfully refreshed from Google Patents.
EP0214018A2
Expired / Lapsed
EP
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Laser beam scanner and its fabricating method
Assignee: Fujitsu Ltd
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Filing: 1986-07-31
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Granted: —
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Expires: 2006-07-31
Abstract
Abstract There is provided a laser beam scanner comprising a beam source (563) for generating a semiconductor laser beam (565): a rotary hologram (721) for diffracting the semiconductor laser beam (565) to form a scanning beam (567) on a surface (564) to be scanned ; and an aberration correcting stationary hologram (561) disposed between the beam source (563) and the rotary hologram (721). wherein the stationary hologram (561) is constructed with an object wave and a reference wave being interfered on a stationary hologram substrate subject that an aberration of the scanning beam (567) on the surface to be scanned shall be corrected, the object wave being a spherical wave having an aberration, a wavelength shorter than that of the semiconductor laser beam (565). and an incident angle which is not vertical but inclined with respect to the stationary hologram substrate.
Inventors
- 👤 Shin-Ya Hasegawa
- 👤 Masayuki Kato
- 👤 Fumio Yamagishi
- 👤 Hiroyuki Ikeda
- 👤 Takefumi Inagaki
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 13:46
CPC Classifications
G; G02; G02B; G02B26/00; G02B26/08; G02B26/10; G02B26/106; Y; Y10; Y10S; Y10S359/00; Y10S359/90
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
157 words
A laser beam scanner apparatus comprising : a beam source (121; 513; 563) for generating a semiconductor laser beam (125; 516; 565); a rotary hologram (122; 721) with variable spatial frequency for diffracting said semiconductor laser beam to form a scanning beam (127; 519; 567) on a surface (124; 515; 564) to be scanned ; and an aberration correcting stationary hologram (112; 511; 521; 561) disposed between said beam source (121; 513; 563) and said rotary hologram (121,721). wherein said stationary hologram (112; 511; 521; 561) is constructed with an object wave and a reference wave being interfered on a stationary hologram substrate subject that an aberration of said scanning beam on said surface to be scanned shall be corrected, said object wave being a spherical wave having an aberration, a wavelength shorter than that of said semiconductor laser beam, and an incident angle which is not vertical but inclined with respect to said stationary hologram substrate.
Claim 2
Dependent Claim
157 words
A laser beam scanner apparatus comprising : a beam source (121; 513; 563) for generating a semiconductor laser beam (125; 516; 565); a rotary hologram (122; 721) with variable spatial frequency for diffracting said semiconductor laser beam to form a scanning beam (127; 519; 567) on a surface (124; 515; 564) to be scanned ; and an aberration correcting stationary hologram (112; 511; 521; 561) disposed between said beam source (121; 513; 563) and said rotary hologram (121,721). wherein said stationary hologram (112; 511; 521; 561) is constructed with an object wave and a reference wave being interfered on a stationary hologram substrate subject that an aberration of said scanning beam on said surface to be scanned shall be corrected, said object wave being a spherical wave having an aberration, a wavelength shorter than that of said semiconductor laser beam, and an incident angle which is not vertical but inclined with respect to said stationary hologram substrate.
Claim 3
Dependent Claim
25 words
An apparatus as claimed in claim 1, wherein said semiconductor laser beam (516) diverged from said beam source (513) irradiates said stationary hologram (521) directly.
Claim 4
Dependent Claim
19 words
An apparatus as claimed in claim 2, wherein said reference wave is a spherical wave having a required aberration.
Claim 5
Dependent Claim
26 words
An apparatus as claimed in claim 3, wherein said required aberration is formed by a convex lens disposed in an optical path of said spherical wave.
Claim 6
Dependent Claim
41 words
An apparatus as claimed in claim 1, wherein said semiconductor laser beam (516) diverging from said beam source (513) irradiates said stationary hologram (511) through an optical lens (514) which converts said semiconductor laser beam (516) into a plane wave (517).
Claim 7
Dependent Claim
20 words
An apparatus as claimed in claim 5, wherein said reference wave for constructing the hologram is a plane wave (517).
Claim 8
Dependent Claim
25 words
An apparatus as claimed in claim 1, wherein said stationary hologram (511; 521; 561) is inclined with respect to said rotary hologram (721) for scanning.
Claim 9
Dependent Claim
43 words
An apparatus as claimed in claim 7, wherein said stationary hologram (511; 521; 561) is inclined with respect to said rotary hologram (721) by an angle with which a positional shift of said scanning beam due to the variation of wavelength is prevented.
Claim 10
Independent Claim
37 words
An apparatus as claimed in any one of claims 1 to 8, wherein said object wave for constructing the hologram is a convergent spherical wave which is made incident to the hologram substrate through a concave lens.
Claim 11
Dependent Claim
30 words
An apparatus as claimed in claim 1, wherein said aberration is corrected such that a uniform aberration is provided for the entire scanning region of said scanning beam (519, 567).
Claim 12
Dependent Claim
18 words
An apparatus as claimed in claim 3, wherein said reference wave for fabricating the hologram has an astigmatism.
Claim 13
Dependent Claim
21 words
An apparatus as claimed in claim 11, wherein said astigmatism of the reference wave is formed by using a cylindrical lens.
Claim 14
Dependent Claim
23 words
An apparatus as claimed in claim 1, wherein said object wave for forming the hologram is a divergent spherical wave having an aberration.
Claim 15
Dependent Claim
23 words
An apparatus as claimed in claim 13. wherein said object wave is a divergent spherical wave which is passed through a convex lens.
Claim 16
Dependent Claim
25 words
An apparatus as claimed in claim 5 or 6, wherein said object wave for forming the hologram is a divergent spherical wave having an aberration.
Claim 17
Independent Claim
28 words
An apparatus as claimed in any one of claims 1 to 3, wherein said reference wave for constructing the hologram is a convergent spherical wave having an aberration.
Claim 18
Dependent Claim
27 words
An apparatusas claimed in claim 16, wherein said reference wave is a convergent spherical wave which is made incident to the hologram substrate through a concave lens.
Claim 19
Dependent Claim
21 words
An apparatus as claimed in claim 7, wherein said stationary hologram is fabricated on a plane side of a plane-convex lens.
Claim 20
Independent Claim
66 words
An apparatus as claimed in any one of claims 1, 13, and 14, wherein said reference wave for fabricating the hologram is a divergent spherical wave which is passed through an aberration correcting lens to have a required aberration, said wave with the aberration being changed to a conjugate wave through a telescopic optical system, and said conjugate wave being made incident to the hologram substrate.
Claim 21
Dependent Claim
51 words
An apparatus as claimed in claim 1, wherein said stationary hologram (511; 521; 561) is fabricated such that a shift of an incident position of the diffracted beam to said rotary hologram is brought within a predetermined extent with respect to a specified variation of wavelength of said semiconductor laser beam.
Claim 22
Dependent Claim
34 words
An apparatus as claimed in claim 1, wherein a position of said beam source (513; 563) of the semiconductor laser beam is adjustable with respect to said stationary hologram in an optical axis direction.
Claim 23
Independent Claim
159 words
A method for forming a laser beam scanner which comprises a beam source (121; 513; 563) for generating a semiconductor laser beam (125; 516; 565), a rotary hologram (122, 721) for diffracting said semiconductor laser beam to form a scanning beam (127; 519; 567) on a surface (124; 515; 564) to be scanned, and an aberration correcting stationary hologram (112; 511; 521; 561) disposed between said beam source (121; 513; 563) and said rotary hologram (122; 721), wherein said stationary hologram (112; 511; 521; 561) is constructed with an object wave and a reference wave being interfered on a stationary hologram substrate subject that an aberration of said scanning beam (127; 519; 567) on said surface to be scanned shall be corrected, said object wave being a spherical wave having an aberration, a wavelength shorter than that of said semiconductor laser beam, and an incident angle which is not vertical but inclined with respect to said stationary hologram substrate.
Claim 24
Independent Claim
159 words
A method for forming a laser beam scanner which comprises a beam source (121; 513; 563) for generating a semiconductor laser beam (125; 516; 565), a rotary hologram (122, 721) for diffracting said semiconductor laser beam to form a scanning beam (127; 519; 567) on a surface (124; 515; 564) to be scanned, and an aberration correcting stationary hologram (112; 511; 521; 561) disposed between said beam source (121; 513; 563) and said rotary hologram (122; 721), wherein said stationary hologram (112; 511; 521; 561) is constructed with an object wave and a reference wave being interfered on a stationary hologram substrate subject that an aberration of said scanning beam (127; 519; 567) on said surface to be scanned shall be corrected, said object wave being a spherical wave having an aberration, a wavelength shorter than that of said semiconductor laser beam, and an incident angle which is not vertical but inclined with respect to said stationary hologram substrate.
References Cited (Backward Citations)
No citation records indexed.
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