EP0469552A2
Expired / Lapsed
EP
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Optical pickup device
Assignee: Omron Corp
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Filing: 1991-07-30
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Granted: —
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Expires: 2011-07-30
Abstract
Abstract An integrated optical pickup device for a magnetooptical recording medium (e.g. a magnetooptical recording disk) and/or an optical recording medium (e.g. an optical recording disk) in which a plurality of focusing grating couplers are formed on an optical waveguide layer manufactured on a substrate. A light reflected from a magnetooptical disk or an optical disk is guided by the focusing grating couplers into the waveguide layer to be separated and to be converged therethtough. The converged lights are detected so as to produce a tracking error signal, a focusing error signal, and an information readout signal. The plural focusing grating couplers are fabricated at an identical location on the waveguide in a superimposed fashion. This increases the utilization efficiency of reflection light per each unitary area of the focusing grating couplers and hence the signals are obtained in a stable state. Between a semiconductor laser and a collimation lens, there is formed a composite beam splitter having two reflection surfaces. Reflection lights from the magnetooptical disk are respectively reflected by these reflection surfaces and are then received by photosensors. Analyzers are disposed respectively on front sides of the photosensors. The analyzers respectively have polarization directions orthogonal to each other. Each photosensor includes three-partition photodiode. The beam sizing method and the push-pull detection methods are used for detecting the focusing and tracking errors. The optical pickup device can also used to read data from an optical disk. A prism is disposed between a semiconductor laser and a collimation lens. The prism has two reflection surfaces. Reflection lights from a magnetooptical disk are respectively reflected by these reflection surfaces to be received by photosensors. On front sides of the photosensors, there are respectively arranged analyzers respectively having polarization directions orthogonal to each other.
Inventors
- 👤 Noriyoshi C/O Omron Corporation Horie
- 👤 Tatsuo C/O Omron Corporation Ohgaki
- 👤 Hayami C/O Omron Corporation Hosokawa
- 👤 Masami C/O Omron Corporation Tada
- 👤 Tsukasa C/O Omron Corporation Yamashita
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-08 01:46
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/12; G11B7/135; G11B7/1356; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B11/10541; G11B11/10543; G11B7/123; G11B7/124; G11B7/1353; G11B7/1359
Claims Analysis
Total Claims: 37
Claim 1
Independent Claim
152 words
An optical pickup device for a magnetooptical recording medium comprising: a light source and a light projecting optical system for emitting a linearly polarized light beam onto a surface of a magnetooptical recoding medium; a waveguide substrate including an optical waveguide, and a plurality of focusing grating couplers formed thereon for respectively exciting lights in the TM and TE modes; a light receiving optical system for delivering a reflection light from the magnetooptical recording medium to said focusing grating couplers on said waveguide substrate; a plurality of photoelectric conversion elements for sensing lights respectively focused by said focusing grating couplers; and signal process means for producing based on signals outputted from said photoelectric conversion elements a tracking error signal, a focusing error signal, and an information readout signal, said plural focusing grating couplers being arranged in a superimposed manner at an identical position on said optical waveguide formed on said waveguide substrate.
Claim 2
Dependent Claim
152 words
An optical pickup device for a magnetooptical recording medium comprising: a light source and a light projecting optical system for emitting a linearly polarized light beam onto a surface of a magnetooptical recoding medium; a waveguide substrate including an optical waveguide, and a plurality of focusing grating couplers formed thereon for respectively exciting lights in the TM and TE modes; a light receiving optical system for delivering a reflection light from the magnetooptical recording medium to said focusing grating couplers on said waveguide substrate; a plurality of photoelectric conversion elements for sensing lights respectively focused by said focusing grating couplers; and signal process means for producing based on signals outputted from said photoelectric conversion elements a tracking error signal, a focusing error signal, and an information readout signal, said plural focusing grating couplers being arranged in a superimposed manner at an identical position on said optical waveguide formed on said waveguide substrate.
Claim 3
Dependent Claim
55 words
An optical pickup device in accordance with claim 1 fruther including a polarizing plate on a front side of the light receiving surface of each said photoelectric conversion element, said polarizing plate passing therethrough a light having a direction of plarization inherent to a light coupling with an associated one of said focusing grating couplers.
Claim 4
Dependent Claim
83 words
An optical pickup device in accordance with claim 1 wherein: at least a portion of said light projecting optical system and said light receiving optical system is shared; said light source is disposed at a position opposite to the magnetooptical recording medium with said waveguide substrate positioned therebetween; and said waveguide substrate includes a transparent portion developing a polarized light - separating function which passes therethrough only a component of the light from said light source, said component having a particular polarization direction.
Claim 5
Dependent Claim
187 words
An optical pickup device for an optical recording medium including: a light source for generating a light beam to be emitted onto a surface of an optical recording medium; a plurality of photoelectric conversion elements for sensing reflection lights from the surface of the optical recording medium; a waveguide substrate having an optical waveguide, a light projection focusing grating coupler formed on said waiveguide for directly emitting lights from said light source onto the surface of the optical recording medium and/or for irradiating the lights via a light projection optical system thereonto, and a light reception focusing grating coupler fabricated on said waveguide for directly receiving reflection lights from the optical recording medium and/or for receiving the lights via a light reception optical system, thereby converging the lights onto said photoelectric conversion elements; and signal process means for generating, based on signals outputted from said photoelectric conversion elements, a tracking error signal, a focusing error signal, and an information readout signal; said light projection and reception focusing grating couplers being formed in a superimposed manner at an identical position of said waveguide manufactured on said waveguide substrate.
Claim 6
Dependent Claim
187 words
An optical pickup device for an optical recording medium including: a light source for generating a light beam to be emitted onto a surface of an optical recording medium; a plurality of photoelectric conversion elements for sensing reflection lights from the surface of the optical recording medium; a waveguide substrate having an optical waveguide, a light projection focusing grating coupler formed on said waiveguide for directly emitting lights from said light source onto the surface of the optical recording medium and/or for irradiating the lights via a light projection optical system thereonto, and a light reception focusing grating coupler fabricated on said waveguide for directly receiving reflection lights from the optical recording medium and/or for receiving the lights via a light reception optical system, thereby converging the lights onto said photoelectric conversion elements; and signal process means for generating, based on signals outputted from said photoelectric conversion elements, a tracking error signal, a focusing error signal, and an information readout signal; said light projection and reception focusing grating couplers being formed in a superimposed manner at an identical position of said waveguide manufactured on said waveguide substrate.
Claim 7
Dependent Claim
54 words
An optical pickup device in accordance with claim 4 wherein: said waveguide substrate is manufactured with a semiconductor material; and said plural photoelectric converter elements are integrally formed on said substrate, said pickup device further including optical couplers disposed in said waveguide for coupling the reflection lights propagating therethrough with said photoelectric conversion elements.
Claim 8
Dependent Claim
124 words
An optical pickup device comprising: a substrate including an optical waveguide formed thereon; a lens function element and grating couplers respectively manufactured at an identical position of said substrate in a superimposed manner; a light source for producing a light for use in a recording operation and/or a reproducing operation; a light projection optical system including said lens function element for focusing and for projecting the light from the light source onto a surface of the optical recording medium; a light reception optical system including said grating couplers for optically coupling a reflection light from the optical receording medium with said optical waveguide on said substrate; and a plurality of photoelectric conversion elements for sensing the lights coupled with said waveguide on said substrate.
Claim 9
Dependent Claim
124 words
An optical pickup device comprising: a substrate including an optical waveguide formed thereon; a lens function element and grating couplers respectively manufactured at an identical position of said substrate in a superimposed manner; a light source for producing a light for use in a recording operation and/or a reproducing operation; a light projection optical system including said lens function element for focusing and for projecting the light from the light source onto a surface of the optical recording medium; a light reception optical system including said grating couplers for optically coupling a reflection light from the optical receording medium with said optical waveguide on said substrate; and a plurality of photoelectric conversion elements for sensing the lights coupled with said waveguide on said substrate.
Claim 10
Dependent Claim
30 words
An optical pickup device in accordance with claim 6 wherein said light source and said light projection optical system are arranged on an optical axis of said lens function element.
Claim 11
Dependent Claim
27 words
An optical pickup device in accordance with claim 6 wherein the optical axis of said lens function element is inclined relative to a plane of said substrate.
Claim 12
Dependent Claim
34 words
An optical pickup device in accordance with claim 6 wherein: said substrate is transparent; and said light source is disposed at a position opposite to the optical recording medium with said substrate enclosed therebetween.
Claim 13
Dependent Claim
41 words
An optical pickup device in accordance with claim 6 wherein: said lens function element is of a reflection type; and said light source and said optical recording medium are arranged at positions on an identical side with respect to said substrate.
Claim 14
Dependent Claim
27 words
An optical pickup device in accordance with claim 6 wherein said lens function element and said grating couplers are formed to be integral with said optical waveguide.
Claim 15
Dependent Claim
96 words
An optical pickup device comprising: a light emitting element; a focusing optical system for converging a light irradiated from said light emitting element onto the optical recording medium and for focusing a reflection light from said optical recording medium; a composite beam splitter having two reflection surfaces for passing therethrough at least a portion of the light emitted from said light emitting element and for reflecting a portion of the reflection light from the optical recording medium into two different directions; and two photosensors for respectively receiving two light beams reflected from said composite beam splitter.
Claim 16
Dependent Claim
96 words
An optical pickup device comprising: a light emitting element; a focusing optical system for converging a light irradiated from said light emitting element onto the optical recording medium and for focusing a reflection light from said optical recording medium; a composite beam splitter having two reflection surfaces for passing therethrough at least a portion of the light emitted from said light emitting element and for reflecting a portion of the reflection light from the optical recording medium into two different directions; and two photosensors for respectively receiving two light beams reflected from said composite beam splitter.
Claim 17
Dependent Claim
33 words
An optical pickup device in accordance with claim 12 further including two analyzers respectively disposed on front sides of said photosensors, said analyzers respectively having polarization directions which are orthogonal to each other.
Claim 18
Dependent Claim
20 words
An optical pickup device in accordance with claim 12 wherein said two reflection surfaces are substantially orthogonal to each other.
Claim 19
Dependent Claim
40 words
An optical pickup device in accordance with claim 12 wherein said two reflection surfaces are substantially parallel to each other and are disposed along a direction of an optical axis of said focusing optical system with a predetermined distance therebetween.
Claim 20
Dependent Claim
120 words
An ptical pickup device comprising: a light emitting element; a focusing optical system for converging a light irradiated from said light emitting element onto an optical recording medium and for focusing a reflection light from the optical recording medium; a composite polarization beam splitter having two polarization reflection surfaces for passing therethrough at least a portion of the light emitted from said light emitting element and for separating a portion of the reflection light from the optical recording medium into two polarized light components having polarization directions orthogonal to each other and for reflecting these polarized light components into two different directions; and two photosensors for respectively receiving two polarized light components thus separated by said composite polarization beam splitter.
Claim 21
Dependent Claim
120 words
An ptical pickup device comprising: a light emitting element; a focusing optical system for converging a light irradiated from said light emitting element onto an optical recording medium and for focusing a reflection light from the optical recording medium; a composite polarization beam splitter having two polarization reflection surfaces for passing therethrough at least a portion of the light emitted from said light emitting element and for separating a portion of the reflection light from the optical recording medium into two polarized light components having polarization directions orthogonal to each other and for reflecting these polarized light components into two different directions; and two photosensors for respectively receiving two polarized light components thus separated by said composite polarization beam splitter.
Claim 22
Dependent Claim
26 words
An optical pickup device in accordance with claim 16 wherein said two polarization reflection surfaces of said composite polarization beam splitter are orthogonal to each other.
Claim 23
Dependent Claim
26 words
An optical pickup device in accordance with claim 12 wherein said composite beam splitter is disposed between said light emitting element and said focusing optical system.
Claim 24
Dependent Claim
35 words
An optical pickup device in accordance with claim 12 wherein: said focusing optical system includes a collimation lens and an objective; and said collimation lens is disposed between said objective and said composite beam splitter.
Claim 25
Dependent Claim
27 words
An optical pickup device in accordance with claim 16 wherein said composite polarization beam splitter is disposed between said light emitting element and said focusing optical system.
Claim 26
Dependent Claim
36 words
An optical pickup device in accordance with claim 16 wherein: said focusing optical system includes a collimation lens and an objective; and said collimation lens is disposed between said objective and said composite polarization beam splitter.
Claim 27
Dependent Claim
87 words
An optical pickup device comprising: a light emitting element; a focusing optical system for converging a light illuminated from said light emitting element onto an optical recording medium and for focusing a reflection light from the optical recording medium; a prism having two reflection surfaces for passing therethrough the light emitted from said light emitting element and for reflecting a portion of the reflection light from the optical recording medium into two different directions; and two photosensors for respectively receiving two light beams reflected from said prism.
Claim 28
Dependent Claim
87 words
An optical pickup device comprising: a light emitting element; a focusing optical system for converging a light illuminated from said light emitting element onto an optical recording medium and for focusing a reflection light from the optical recording medium; a prism having two reflection surfaces for passing therethrough the light emitted from said light emitting element and for reflecting a portion of the reflection light from the optical recording medium into two different directions; and two photosensors for respectively receiving two light beams reflected from said prism.
Claim 29
Dependent Claim
37 words
An optical pickup device according to claim 22 further including two analyzers disposed respectively on front sides of light receiving surfaces of said photosensors, said two analyzers respectively having polarization directions which are orthogonal to each other.
Claim 30
Dependent Claim
41 words
An optical pickup device according to claim 22 wherein, in order for said two photosensors to receive from said prism substantially an identical amount of reflection light, each of said reflection surfaces of said prism is coated with a reflection film.
Claim 31
Dependent Claim
109 words
An optical pickup device comprising: a light emitting element; a focusing optical system for converging a light irradiated from said light emitting element onto an optical recording medium and for focusing a reflection light from the optical recording medium; a prism having two polarization reflection surfaces for passing therethrough the light emitted from said light emitting element and for separating a portion of the reflection light from the optical recording medium into polarized components respectively having polarization directions which are orthogonal to each other, thereby reflecting the polarized light components into two different directions; and two photosensors for respectively receiving two polarized light components thus separated by said prism.
Claim 32
Dependent Claim
109 words
An optical pickup device comprising: a light emitting element; a focusing optical system for converging a light irradiated from said light emitting element onto an optical recording medium and for focusing a reflection light from the optical recording medium; a prism having two polarization reflection surfaces for passing therethrough the light emitted from said light emitting element and for separating a portion of the reflection light from the optical recording medium into polarized components respectively having polarization directions which are orthogonal to each other, thereby reflecting the polarized light components into two different directions; and two photosensors for respectively receiving two polarized light components thus separated by said prism.
Claim 33
Dependent Claim
22 words
An optical pickup device in accordance with claim 25 wherein said polarization reflection surfaces of said prism are orthogonal to each other.
Claim 34
Dependent Claim
24 words
An optical pickup device in accordance with claim 22 wherein said prism is disposed between said light emitting element and said focusing optical system.
Claim 35
Dependent Claim
33 words
An optical pickup device in accordance with claim 22 wherein: said focusing optical system includes a collimation lens and an objective; and said collimation lens is located between said objective and said prism.
Claim 36
Dependent Claim
25 words
An optical pickup device in accordance with claim 25 wherein said prism is disposed between said light emitting element and said light focusing optical system.
Claim 37
Dependent Claim
33 words
An optical pickup device in accordance with claim 25 wherein: said focusing optical system includes a collimation lens and an objective; and said collimation lens is located between said objective and said prism.
References Cited (Backward Citations)
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