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EP0280208A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Optical head

Assignee: Hitachi Ltd
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Filing: 1988-02-19
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Granted: —
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Expires: 2008-02-19
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Abstract

Abstract An optical head including a substrate (1), an optical waveguide (3) formed on the substrate, a light source (4) formed on a portion of the substrate, a collimator lens (5) for converting light from the light source into parallel light rays, an objective lens (8) for focusing light from the collimator lens on a record­ing medium (16) and for converting reflected light from the recording medium into parallel light rays, a beam splitter (9) for dividing light from the objective lens into two parts to send out one of the parts in a pre­determined direction, a coupling lens (11) for focusing light from the beam splitter on a position, and a photo­detector (10) for detecting light from the coupling lens, is disclosed, in which the collimator lens (5), the objective lens (8), the beam splitter (9), the coupling lens (11) and the photodetector (10) are integrated on the substrate (1), and the collimator lens (5) or an objective lens supporting part is made flexible to vary the position of the focus of the collimator lens (5) or objective lens (8) by piezo-electric elements (29, 30; 55a to 55d).

Inventors

  • 👤 Satoshi Shimada
  • 👤 Shinji Ohyama
  • 👤 Manabu Sato
  • 👤 Masahiko Ibamoto
  • 👤 Yoshio Sato
  • 👤 Nobuyoshi Tsuboi
  • 👤 Norifumi Miyamoto
  • 👤 Hiroyuki Minemura
  • 👤 Hiroaki Koyanagi

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-09 06:05
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/10; G02B6/12; G02B6/122; G02B6/124; G02B6/12004; G02B6/1245; G11; G11B; G11B7/00; G11B7/08; G11B7/09; G11B7/0908; G11B7/0912; G11B7/12; G11B7/123; G11B7/124; G11B7/1245

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 194 words
An optical head including a substrate (1), an optical waveguide (3) formed on the substrate, a light source (4) formed on a portion of the substrate, a collimator lens (5) for converting light from the light source into parallel light rays, an objective lens (8) for focusing light from the collimator lens on a record­ing medium (16) and for converting reflected light from the recording medium into parallel light rays, a beam splitter (9) for dividing light from the objective lens into two parts to send out one of the parts in a pre­determined direction, a coupling lens (11) for focusing light from the beam splitter on a position, and a photo­detector (10) for detecting light from the coupling lens, wherein the collimator lens (5), the objective lens (8), the beam splitter (9), the coupling lens (11) and the photodetector (10) are integrated on the substrate (1), and at least one of the collimator lens (5) and an objective lens supporting part is made flexible to vary the position of the focus of at least one of the collimator lens (5) and the objective lens (8) by piezo­electric elements (29, 30; 55a to 55d).
Claim 2
Dependent Claim 194 words
An optical head including a substrate (1), an optical waveguide (3) formed on the substrate, a light source (4) formed on a portion of the substrate, a collimator lens (5) for converting light from the light source into parallel light rays, an objective lens (8) for focusing light from the collimator lens on a record­ing medium (16) and for converting reflected light from the recording medium into parallel light rays, a beam splitter (9) for dividing light from the objective lens into two parts to send out one of the parts in a pre­determined direction, a coupling lens (11) for focusing light from the beam splitter on a position, and a photo­detector (10) for detecting light from the coupling lens, wherein the collimator lens (5), the objective lens (8), the beam splitter (9), the coupling lens (11) and the photodetector (10) are integrated on the substrate (1), and at least one of the collimator lens (5) and an objective lens supporting part is made flexible to vary the position of the focus of at least one of the collimator lens (5) and the objective lens (8) by piezo­electric elements (29, 30; 55a to 55d).
Claim 3
Dependent Claim 68 words
An optical head according to Claim 1, wherein the collimator lens (5) is formed of a flexible disk which can be convex downwardly or upwardly, and a piezo-­electric element (29) mounted on a central portion of the collimator lens (5) and another piezo-electric element (30) mounted on a peripheral portion of the collimator lens (5) are so operated as to be opposite in driving polarity to each other.
Claim 4
Dependent Claim 59 words
An optical head according to Claim 1, wherein a portion of the substrate (1) is made thin so that a flexible supporting part is formed around the objective lens (8), and inner and outer piezo-electric elements (55b, 55c; 55a, 55d) mounted on the flexible supporting part are so operated as to be opposite in driving polarity to each other.
Claim 5
Dependent Claim 22 words
An optical head according to Claim 1, wherein the objective lens (8) is formed of a curved grating having a blaze angle.
Claim 6
Dependent Claim 39 words
An optical head according to Claim 1, wherein a surface acoustic wave element (45) is mounted on a portion of the substrate (1) to form an optical deflector (6), thereby deflecting light which passes through the optical waveguide (3).
Claim 7
Dependent Claim 40 words
An optical head according to Claim 1, wherein light emitted from the light source (4) is converted by a second-order higher harmonic generator (60) into light having a shorter wavelength, to increase the recording density in the recording medium (16).

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