Sharp Kabushiki Kaisha Corporation

Sharp Kabushiki Saisha

Yoshio Yoshida

Yukio Kurata

Takahiro Miyake

Hiroyuki Yamamoto

Yasuo Nakata

Kuniaki Okada

Keiji Sakai

Nobuo Ogata

Kohji Minami

Toshiya Nagahama

Kouji Minami

Hideaki Sato

Katsuhiro Kubo

Tetsuo Ueyama

Toshio Ishikawa

Renzaburo Miki

Toshiyuki Tanaka

Mitsuo Ishii

Shigeki Tsuji

Atsushi Asada

Motohiko Yamamoto

Yukinori Nishitani

Renzaburou Miki

Etsuji Minami

Akihito Yoshimoto

Kazuko Inoue

Takayuki Inoue

Katushiro Kubo

Yukio Kubata

Hideaki Satou

Teruaki Inoue, Deceased

In manufacturing an optical pickup, an adhesive is applied between an optical waveguide device and a wedge-shaped device fixing member, and an adhesive is applied between the wedge-shaped device fixing member and a stem. After the position of the optical waveguide device is adjusted in three-dimensional directions of an optical axis direction and directions orthogonal to the optical axis by moving the wedge-shaped device fixing member, the optical waveguide device and the wedge-shaped device fixing member are fixed.

Optical pickup having optical waveguide device fixed on stem with wedge-shaped device fixing member interposed and method of manufacturing the same

In an optical pickup, a beam splitter is arranged on an optical path between a hologram and a grating. Beam splitter includes a first reflecting surface reflecting part of a beam reflected from a disk, and a second reflecting surface arranged parallel to the first reflecting surface. Part of the beam which is reflected from the disk and passed through hologram is reflected at the first reflecting surface and thereafter reflected by the second reflecting surface of beam splitter, and thereafter directed to optical waveguide device, whereby a signal recorded on the disk is detected (reproduced). The beam which has transmitted through hologram and the first reflecting surface is directed to photodiode and detected as a servo error signal.

Optical pickup integrated with optical system

A polarization detection device includes a photocoupler; an optical waveguide layer for propagating light from the photocoupler therethrough; a polarization splitter for splitting the propagation light into two components having different refractive angles; and a photodetector formed of a semiconductor material for performing photoelectric conversion on the propagation light split into the two components. The photocoupler, the optical waveguide layer, the polarization splitter, and the photodetector are provided on a single semiconductor substrate. The photocoupler is one of a prism and a beam splitter formed of a dielectric material and supported by the optical waveguide layer only by an adhesive layer, the adhesive layer having a straight edge in the vicinity of the photocoupler. The adhesive layer has a thickness d fulfilling expression (1) where a longer diameter of a beam spot of the light incident on the photocoupler on an interface between the adhesive layer and the optical waveguide layer is L, and the angle of incidence of the light with respect to the optical waveguide layer is .theta.:

Polarization detection device and method for producing the same

A waveguide-photodetector includes a semiconductor substrate; a waveguide section, provided on the semiconductor substrate, for propagating light; an opto-electric converting section, provided in the semiconductor substrate, for converting the light into an electric signal; and an insulative layer provided between the semiconductor substrate and the waveguide section. The waveguide section includes at least an introducing part for introducing the light to the waveguide section, a coupling part for coupling the light introduced to the waveguide section to the opto-electric converting section, and a propagating part for propagating the light from the introducing part to the coupling part. The insulative layer includes a first region for defining a position and a shape of an impurity diffused region of the opto-electric converting section, a second region which encloses the first region and is thicker than the first region, and a step portion between the first region and the second region. The introducing part, the propagating part and the coupling part of the waveguide section are located on the first region.

Waveguide-photodetector, method for producing the same, waveguide usable

A method for producing a tapered waveguide is produced using an undercut-type shadow mask having an overhanging part. The shadow mask includes a photoresist layer having the overhanging part and a metal layer for supporting the photoresist layer on a substrate. After the shadow mask is provided on the substrate, film-forming particles are caused to jump from above the shadow mask toward the substrate, thereby forming a dielectric film having a tapered part on the substrate. Then, the shadow mask is removed together with the film-forming particles thereon by lift-off. Then, an optical waveguide is formed on the substrate so as to cover the dielectric film having the tapered part. The thickness of the metal layer is preferably in the range of about 0.1 to 10 .mu.m and more preferably about 1 .mu.m.

Method for producing tapered waveguide

A method for producing a photocoupler includes the steps of: forming a waveguide structure on a substrate; forming a photoresist layer having a groove on the waveguide structure; mounting a prism on the photoresist layer so as to partially cover the groove; bonding the prism on the waveguide structure by injecting an adhesive into the groove; and removing the photoresist layer. The groove has a T-shaped pattern including a transverse section extending in a first direction and a longitudinal section extending in a second direction perpendicular to the first direction. The transverse section has a first width in the second direction which is smaller than a second length of a bonding face of the prism in the second direction. The prism is bonded to the waveguide structure through the bonding face. The longitudinal section has a second width in the first direction which is smaller than a first length of the bonding face of the prism in the first direction. The transverse section has a first length in the first direction which is greater than the first length of the bonding face of the prism in the first direction. The longitudinal section has a second length in the second direction which is greater than the second length of the bonding face of the prism in the second direction. The adhesive is injected into an end portion of the longitudinal section which is distanced away from the transverse section, the end portion not being covered by the prism.

Method for producing a photocoupler and a photocoupler produced by the

The optical pickup device according to the present invention, includes: a light emitting diode for emitting a light beam; a collimating lens for collimating the light beam; an objective lens for focusing the collimated light beam from the collimating lens onto a recording medium; a beam splitter for splitting the light beam returned from the recording medium into two light beams; a servo error signal detector for receiving one of the two light beams and detecting a servo error signal; a diffracting element for diffracting the one of the two light beams from the beam splitter to direct the one of the two light beams toward the servo error signal detector; and an optical waveguide element for receiving the other one of the two light beams and detecting a magneto-optical signal, the other one of the two light beams from the beam splitter being incident upon the optical waveguide element without passing through the diffracting element, wherein the beam splitter is disposed between the collimating lens and the diffracting element.

Compact optical pickup device with beam splitter

A mode splitter and the magneto-optical pick-up device including the mode splitter. The mode splitter includes a tapered waveguide portion whose thickness gradually becomes thin so that a light of at least one mode can be cut off. An emission position of a light wave can be varied depending on its mode. In this mode splitter, the emission position of the light wave of each mode can be adjusted by changing a thickness of the tapered waveguide, thereby improving the degree of freedom in designing the device.

Magneto-optical disk pick-up device having mode splitter using cut off

An optical coupler of the present invention includes: an optical waveguide including a substrate, a first dielectric layer formed on the substrate, a second dielectric layer which is formed on the first dielectric layer and has a refractive index lower than a refractive index of the first dielectric layer, and a third dielectric layer which is formed on a part of the second dielectric layer and has a refractive index equal to or lower than the refractive index of the second dielectric layer; and a light introducing portion made of a transparent material having a refractive index higher than the refractive index of each of the dielectric layers, the light introducing portion being formed on the optical waveguide and introducing converged incident light into the optical waveguide, wherein the light introducing portion is provided across a surface of the second dielectric layer and a surface of the third dielectric layer and has, as a light incident surface, a flat portion allowing the incident light introduced into the optical waveguide to pass through without eclipse.

Optical coupler and method for producing the same

A method for producing a tapered waveguide layer is disclosed. The method includes the steps of: forming a resist pattern on a substrate; setting the substrate in an apparatus for forming a film such that particles constituting the film reach the substrate from a direction which is oblique relative to the substrate; forming the film on a region of a surface of the substrate which is not covered by the resist pattern, the film having a thickness distribution corresponding to a shadow which the resist pattern creates on the substrate in accordance with an angle between the substrate and the direction; and removing the resist pattern, thereby forming the tapered waveguide layer consisting of the film on the substrate.

Method for producing a tapered waveguide

The optical pickup of the invention includes a hologram mirror for directing an optical axis of a light beam emitted from a light source to be perpendicular to the recording face of a recording medium. The hologram mirror includes: a light transmissive substrate having a first surface and a second surface which are opposite to each other, the light beam from the light source entering the substrate from the first surface; a transmissive holographic element, formed on the first substrate, for diffracting the light beam incident thereon to generate a plurality of diffracted beams; and a reflective film, formed on the second surface of the substrate, for reflecting the diffracted beams, wherein the holographic element includes a blazed grating which is designed to make a predetermined one of the diffracted beams most intense.

Optical pickup

A mode splitter and the magneto-optical pick-up device including the mode splitter are provided. The mode splitter includes a tapered waveguide portion whose thickness gradually becomes thin so that a light of at least one mode can be cut off. An emission position of a light wave can be varied depending on its mode. In this mode splitter, the emission position of the light wave of each mode can be adjusted by changing a thickness of the tapered waveguide, thereby improving the degree of freedom in designing the device.

Mode splitter and a magneto-optical disk pick-up device having the mode

A polarization detector includes a polarization diffraction element having a substrate with two facing surfaces which are placed in parallel with each other, a first diffraction grating formed on one surface of the substrate, and a second diffraction grating formed on the other surface of the substrate, with light being incident upon the first diffraction grating. Further, each grating pitch of the first diffraction grating and the second diffraction grating are nearly equal to a wavelength of the incident light. A limiting member is also included for limiting an incident region of the incident light with respect to the polarization diffraction element. The limiting member is formed on a light incident side of the first diffraction grating. Further, a converging lens is included for respectively converging light transmitted through the first diffraction grating and the second diffraction grating and light diffracted by the first diffraction grating and the second diffraction grating into different beam spots. Finally, a pair of photodetectors are included for detecting each optical intensity of the two beam spots converged by the converging lens.

Polarization detector

A display apparatus of the invention includes: a plurality of display devices arranged in one direction, each of the plurality of display devices having a display area; and a plurality of image transmission means corresponding to the respective display devices, one end face of each of the image transmission means being coupled to a display area of the corresponding one of the display devices, other end faces of the image transmission means corresponding to the adjacent ones of the display devices being in contact with each other, the plurality of image transmission means being bent toward the one direction in which the display devices are arranged. Alternatively, a display apparatus of the invention includes: a plurality of display devices disposed in two directions, each of the plurality of display devices having a display area; a plurality of image transmission means corresponding to the respective display devices, one end face of each of the image transmission means being coupled to a display area of the corresponding one of the display devices, other end faces of the image transmission means corresponding to the adjacent ones of the display devices being in contact with each other, some of the plurality of image transmission means each having inward facing slopes and outward facing slopes on two pairs of opposing faces, the outward facing slopes of the image transmission means being directed to a direction in which the corresponding display device has no adjacent display devices.

Display apparatus having a plurality of display devices

An optical information reproducing apparatus of the invention includes a light emitting and receiving unit and an optical system. The optical system converges light from the light emitting and receiving unit on a recording medium and converges the light after reflected by the recording medium. The light emitting and receiving unit includes: a semiconductor laser device disposed on a substrate for generating light; a photo detector formed, integrally with the substrate, on the substrate on which the semiconductor laser device is disposed, for outputting a signal corresponding to the intensity of light incident thereon; and a beam splitter provided on an optical axis of the reflected light, the beam splitter leading part of the reflected light to the photo detector.

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Nara, Japan

Yoshio Yoshida