GB2139784A
Expired / Lapsed
GB
⏱️ 0.0 years remaining
Optical information processing apparatus
Assignee: Canon Inc
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Filing: 1984-03-26
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Granted: —
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Expires: 2004-03-26
Abstract
Abstract This specification discloses an optical information processing apparatus in which a primary radiation beam is applied to an information track on a recording medium to reproduce information and at least two secondary radiation beams are applied to positions different from each other widthwise of the information track to which the primary beam has been applied and the beam from the recording medium, of the secondary beams, is detected to thereby obtain a tracking signal for accurately directing the primary beam to the information track, characterized in that the primary beam and the secondary beams have different wavelengths and these beams emitted from discrete radiation sources are combined together and directed to the recording medium through a common optical path. <IMAGE>
Inventors
- 👤 Masamichi Tateoka
- 👤 Mitsuhiro Tokuhara
Bibliographic Details
Application Number
—
Jurisdiction
GB
Data Source
google_patents
Last Synchronized
2026-10-25 17:01
CPC Classifications
G; G11; G11B; G11B11/00; G11B11/10; G11B13/00; G11B13/04; G11B13/045; G11B7/00; G11B7/08; G11B7/09; G11B7/0901; G11B7/0903
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
116 words
An optical information processing apparatus in which a primary radiation beam is applied to an information track on a recording medium to reproduce information and at least two secondary radiation beams are applied to positions different from each other widthwise of the information track to which said primary beam has been applied and the beam from the recording medium, of said secondary beams, is detected to thereby obtain a tracking signal for accurately directing said primary beam to the information track, characterized in that said primary beam and said secondary beams have different wavelengths and these beams emitted from discrete radiation sources are combined together and directed to the recording medium through a common optical path.
Claim 2
Dependent Claim
116 words
An optical information processing apparatus in which a primary radiation beam is applied to an information track on a recording medium to reproduce information and at least two secondary radiation beams are applied to positions different from each other widthwise of the information track to which said primary beam has been applied and the beam from the recording medium, of said secondary beams, is detected to thereby obtain a tracking signal for accurately directing said primary beam to the information track, characterized in that said primary beam and said secondary beams have different wavelengths and these beams emitted from discrete radiation sources are combined together and directed to the recording medium through a common optical path.
Claim 3
Dependent Claim
35 words
An optical information processing apparatus according to Claim 1, wherein the information track on said recording medium is recorded by modulating said primary beam in accordance with the information and applying itto said recording medium.
Claim 4
Dependent Claim
29 words
An optical information processing apparatus according to Claim 2, wherein said secondary beams are not applied to the recording medium when information is being recorded by said primary beam.
Claim 5
Dependent Claim
50 words
An optical information processing apparatus according to Claim 1, wherein said secondary beams are formed by the use of a radiation source and an optical wedge member for dividing the radiation beam emitted from said radiation source into two beams and having two reflecting surfaces forming a predetermined angle therebetween.
Claim 6
Dependent Claim
61 words
An optical information processing apparatus according to Claim 1, wherein said primary beam and said secondary beams are applied to the recording medium through an objective lens, and said optical wedge member is disposed so that the principle rays of the secondary beams reflected by the respective reflecting surfaces thereof travel toward the center of the pupil of said objective lens.
Claim 7
Dependent Claim
32 words
An optical information processing apparatus according to Claim 1, wherein said primary beam and said secondary beams are combined together by a beam splitter whose transmittance and reflectance differ depending on wavelength.
Claim 8
Dependent Claim
18 words
An optical information processing apparatus according to Claim 1, wherein said recording medium comprises an erasable recording medium.
Claim 9
Dependent Claim
25 words
An optical information processing apparatus according to Claim 7, wherein the information recorded on said recording medium is erased by applying said primary beam thereto.
Claim 10
Dependent Claim
18 words
An optical information processing apparatus according to Claim 7, wherein said recording medium comprises a magneto-optical recording medium.
Claim 11
Dependent Claim
149 words
An optical information processing apparatus comprising:
a first radiation source for emitting a first radiation beam modulated in conformity with information;
a second radiation source for emitting a second radiation beam different in wavelength from said first beam;
dividing means for dividing said second beam into two beams;
an optical system for combining said first beam with said divided second beams and for directing the same to a recording medium through a common optical path, said first beam being applied by said optical system to a guide track provided in the recording medium in advance, said divided two second beams being applied to positions different from each otherwidthwise of the guide track to which said first beam is applied; and
detecting means for receiving the beam from the recording medium, of said second beam, and obtaining a tracking signal for accurately directing said first beam to the guide track.
Claim 12
Dependent Claim
149 words
An optical information processing apparatus comprising:
a first radiation source for emitting a first radiation beam modulated in conformity with information;
a second radiation source for emitting a second radiation beam different in wavelength from said first beam;
dividing means for dividing said second beam into two beams;
an optical system for combining said first beam with said divided second beams and for directing the same to a recording medium through a common optical path, said first beam being applied by said optical system to a guide track provided in the recording medium in advance, said divided two second beams being applied to positions different from each otherwidthwise of the guide track to which said first beam is applied; and
detecting means for receiving the beam from the recording medium, of said second beam, and obtaining a tracking signal for accurately directing said first beam to the guide track.
Claim 13
Dependent Claim
27 words
An optical information processing apparatus according to Claim 10, wherein said dividing means comprises an optical wedge member having two reflecting surfaces forming a predetermined angle therebetween.
Claim 14
Dependent Claim
59 words
An optical information processing apparatus according to Claim 11, wherein said first and second beams are applied to the recording medium through an objective lens, and said optical wedge member is disposed so that the principle rays of the second beams reflected by the respective reflecting surfaces thereof travel toward the center of the pupil of said objective lens.
Claim 15
Dependent Claim
32 words
An optical information processing apparatus according to Claim 10, wherein said first beam and said second beam are combined together by a beam splitter whose transmittance and reflectance differ depending on wavelength.
Claim 16
Dependent Claim
93 words
Apparatus for recording information on and/ or reading information from, a recording medium using a primary beam of electromagnetic radiation, wherein there is provided tracking means for causing the point of impingement of said primary beam on said recording medium to conform to a desired tracking path, said tracking means comprising means for directing tracking electromagnetic radiation onto said medium in the region of said point of impingement, and means for detecting tracking radiation from said medium to produce a tracking signal, said tracking radiation and said primary beam radiation having different characteristics.
Claim 17
Dependent Claim
93 words
Apparatus for recording information on and/ or reading information from, a recording medium using a primary beam of electromagnetic radiation, wherein there is provided tracking means for causing the point of impingement of said primary beam on said recording medium to conform to a desired tracking path, said tracking means comprising means for directing tracking electromagnetic radiation onto said medium in the region of said point of impingement, and means for detecting tracking radiation from said medium to produce a tracking signal, said tracking radiation and said primary beam radiation having different characteristics.
Claim 18
Dependent Claim
51 words
Apparatus for recording information on and reading information from a recording medium using electromagnetic radiation, wherein means is provided for selectively deriving from a common beam source and directing onto the medium via a common optical path a recording beam or a reading beam, said recording beams differing in beam intensity.
Claim 19
Dependent Claim
51 words
Apparatus for recording information on and reading information from a recording medium using electromagnetic radiation, wherein means is provided for selectively deriving from a common beam source and directing onto the medium via a common optical path a recording beam or a reading beam, said recording beams differing in beam intensity.
Claim 20
Dependent Claim
82 words
Apparatus according to claim 15 wherein there is further provided tracking means including a source of tracking electromagnetic radiation, means for directing said tracking radiation onto said medium via an optical path partly common with that of said recording or reading beam, means for detecting tracking radiation from the medium to produce a tracking signal, and means responsive to said tracking signal to cause the point of impingement of the recording or reading beam on the medium t6 follow a desired track.
Claim 21
Dependent Claim
56 words
Apparatus according to claim 14 or claim 16 wherein said tracking means is arranged to form a pair of tracking beams and to cause said tracking beams to impinge on said recording medium at respective points which are laterally spaced in opposite directions from the track of the impingement point of the recording or reading beam.
Claim 22
Dependent Claim
20 words
An optical information processing apparatus substantially as hereinbefore described with reference to Figure 2 of 4 of the accompanying drawings.
Claim 23
Dependent Claim
20 words
An optical information processing apparatus substantially as hereinbefore described with reference to Figure 2 of 4 of the accompanying drawings.
References Cited (Backward Citations)
No citation records indexed.
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