Sanyo Electric Co., Ltd.

Atsushi Tajiri

Kazushi Mori

Minoru Sawada

Yasuaki Inoue

Takenori Goto

Akira Ibaraki

Koji Tominaga

Mitsuaki Matsumoto

Daisuke Ide

Koutarou Furusawa

Takao Yamaguchi

Masayuki Shono

Keiichi Yodoshi

Yasuhiko Nomura

Ryoji Hiroyama

Toyozo Nishida

Yasuhiro Ueda

Tatsuhiko Niina

A method of manufacturing an element having a microstructure of an excellent grating groove pattern or the like is obtained. This method of manufacturing an element having a microstructure comprises steps of forming a metal layer on a substrate, forming a dot column of concave portions on the surface of the metal layer and anodically oxidizing the surface of the metal layer formed with the dot column of concave portions while opposing this surface to a cathode surface thereby forming a metal oxide film having a grating groove pattern. When the interval between the concave portions of the dot column is reduced, therefore, a linear grating groove pattern having a large depth with a uniform groove width along the depth direction is easily formed in a self-organized manner.

Element having microstructure and manufacturing method thereof

Method of forming grating microstrutures by anodic oxidation

In a holographic pattern provided in a holographic optical element, a patterntwists a diffracted light beam in a clockwise direction, to form a semi-circular light spot Sa on photodetection parts A and B so as to extend over a dividing line LX in a four-segment photodetection part. A patternsimilarly twists the diffracted light beam in a clockwise direction, to form a semi-circular light spot Sb on photodetection parts C and D so as to extend over a dividing line LX in the four-segment photodetection part.

Holographic optical element, position shift detecting apparatus, optical pickup apparatus, optical recording medium drive and method of fabricating holographic optical element

A surface emission semiconductor laser device capable of substantially completely controlling the plane of polarization is obtained. This surface emission semiconductor laser device comprises a first multi-layer reflector, an emission layer formed on the first multi-layer reflector and a second multi-layer reflector formed on the emission layer, and at least either the first multi-layer reflector or the second multi-layer reflector includes a striped part worked in a striped manner in a prescribed period.

Surface emission semiconductor laser device

Method of forming grating microstructures by anodic oxidation

A six-segment holographic surface is divided into regions by dividing lines. A four-segment photodetection part is divided into four photodetection parts equal in area by a section line substantially parallel to the radial direction of an optical disk and a section line orthogonal thereto. A main light beam diffracted in the regions of the six-segment holographic surface are condensed as spots at positions apart from each other on opposite sides on a section line of the four photodetection parts, and the main beam diffracted in the regions is condensed as spots in the center of the photodetection parts of the four-segment photodetection part.

Optical pickup with a diffraction element consist of six regions providing spatial variation corresponding to a focas state

A grating surface of a diffraction grating diffracts a laser beam emitted from a semiconductor laser device in &plusmn;1st order directions. The grating surface is formed in a rectangular or elliptic shape in such dimensions that a light spot formed on an objective lens by &plusmn;1st order diffracted beams is located in an aperture of the objective lens and not displaced from the aperture even if the objective lens is horizontally moved in a tracking operation. A grating surface of another diffraction grating has a width smaller than the width of an overlap region of a light spot on the diffraction grating corresponding to a part of a beam, diffracted in the &plusmn;1st direction, entering an objective lens and a light spot on the diffraction grating corresponding to a part of a beam, diffracted in the &minus;1st direction, entering the objective lens.

Optical pickup apparatus employing an adjusting circuit

A grating surface of a diffraction grating diffracts a laser beam emitted from a semiconductor laser device in &plusmn;1st order directions. The grating surface is formed in a rectangular or elliptic shape in such dimensions that a light spot formed on an objective lens by &plusmn;1st order diffracted beams is located in an aperture of the objective lens and not displaced from the aperture even if the objective lens is horizontally moved in a tracking operation. A grating surface of another diffraction grating has a width smaller than the width of an overlap region of a light spot on the diffraction grating corresponding to a part of a beam, diffracted in the &plus;1st direction, entering an objective lens and a light spot on the diffraction grating corresponding to a part of a beam, diffracted in the &minus;1st direction, entering the objective lens.

Optical pickup apparatus capable of suppressing offset of a tracking error signal

First and second photodiodes are arranged on the upper surface of a stem, returned light beams diffracted in the &plus; 1st order by a transmission type holographic optical element are received by the first photodiode, while returned light beams diffracted in the &minus; 1st order are received by the second photodiode. The first photodiode has a plurality of light receiving regions, and respectively outputs a reproducing signal, a focus error signal and a tracking error signal on the basis of the returned light beams. On the other hand, the second photodiode has a single light receiving region, and outputs a reproducing signal on the basis of the returned light beams.

Optical pickup apparatus and optical recording medium drive employing the same including a first photo receiving element for detecting the state of light beam and a second photo receiving element for reproducing information

A transmission-type holographic optical element has a four-segment holographic surface divided into four regions of equal areas by virtual dividing lines which are perpendicular to each other. The first dividing line is at an angle with respect to the track direction of an optical disk and the second dividing line is at an angle with respect to the radial direction of the optical disk before tracking phase adjustment. The first dividing line coincides with the track direction of the optical disk and the second dividing line coincides with the radial direction of the optical disk after tracking phase adjustment. A four-segment photodetection part is divided into four photodetection parts of equal areas by a dividing line substantially parallel to the radial direction of the optical disk and a dividing line perpendicular thereto. Parts of a main beam diffracted in two regions located on first diagonal positions of the four-segment holographic surface are condensed as condensed spots on adjacent positions of the first dividing line of the four-segment photodetection part on opposite sides, and parts of the main beam diffracted in the remaining two regions located on second diagonal positions are condensed as condensed spots on separate positions of the second dividing line of the four-segment photodetection part on opposite sides.

Optical pickup apparatus and optical recording medium drive employing

An optical pickup device of the present invention includes a substrate having at least a major surface, a semiconductor laser provided on the surface of the substrate for emitting laser beam, a reflection-type diffraction grating oriented to the semiconductor laser for splitting the laser beam into at least three beams and reflecting them upward, a hologram for receiving the three beams reflected from the reflection-type diffraction grating, and an objective lens for converging onto an optical recording medium the three beams transmitted by the hologram. The three beams reflected from the optical recording medium are focused by the hologram and directed onto the photodetector from the above.

Optical pickup device

A semiconductor laser device is mounted on the side of one end surface on lead frame in a recess of an insulating molding member, a three-beam generating diffraction grating is disposed in the center, and a transmission type holographic optical element is disposed on the side of the other end surface. After a flexible circuit board is fixed to the lower surfaces of leads and the lead frame, a photodiode for a signal detection is mounted on the surface of the flexible circuit board, and is so folded upward as to be perpendicular to the upper surface of the lead frame. The insulating molding member is mounted on the one end surface of the insulating molding member through a circular screw through a hole and an elliptic screw through a hole by screws.

Optical head with a photo-detector mounted on a flexible circuit board

An optical pickup device has a case constructed by joining a lower frame member and an upper frame member. A semiconductor laser device, a three-beam generating diffraction grating, a transmission type holographic optical element, and a reflecting mirror are arranged in the lower frame member. A lead frame is arranged in the lower frame member. The semiconductor laser device is arranged on the lead frame through a heat sink, to emit laser light in a horizontal direction. A photodiode and the lead frame are arranged in the upper frame member. The photodiode has a light receiving surface parallel to the direction of light emission from the semiconductor laser device, and is mounted on the lead frame. The laser light emitted from the semiconductor laser device passes through the three-beam generating diffraction grating and the transmission type holographic optical element, and is then bent upward and introduced into an optical recording medium. Returned light reflected from a recording surface of the optical recording medium is changed in a direction parallel to the direction of light emission from the semiconductor laser device, passes through the transmission type holographic optical element and the three-beam generating diffraction grating again, is then changed vertically upward by the reflecting mirror, and is incident on the photodiode.

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Osaka, Japan

Atsushi Tajiri