Sharp Kabushiki Kaisha Corporation

Osamu Miyazaki

Yukio Watanabe

Tetsuo Ueyama

Keiji Sakai

Kazunori Matsubara

Shinzoh Murakami

Kazuhiro Tsuchida

Hiroshi Nakanishi

Takahiro Miyake

Kazuya Yoshimura

Yasuo Nakata

Ikuo Nakano

Akihisa Iwamoto

Renzaburo Miki

Noboru Fujita

Renzaburou Miki

Toshiyuki Makii

Tomio Mashiyama

Yasukazu Tomita

Syunji Nakai

Masuji Tanimura

Masami Inoue

Hiroshige Makioka

An optical pickup device includes: a splitting section for splitting a beam; a light-receiving section for receiving the split beams. The light-receiving section includes: a tracking-use main light-receiving region and tracking-use sub light-receiving regions, and auxiliary light-receiving regions. Each of the auxiliary light-receiving regions receives only a light beam reflected off a recording layer other than a recording layer subjected to an information writing/reading process. A light-receiving area of each of the auxiliary light-receiving area is smaller than a light-receiving area of each tracking-use light-receiving region. Further, an optical pickup device includes: a splitting section for splitting a beam; and a light-receiving section for receiving the split beams. The light-receiving section includes a sub light-receiving regions for receiving tracking-use sub beams. The tracking-use sub beams are arranged so as not to allow entering of a focusing-use main beam reflected off a non-targeted recording layer.

Optical pickup unit and optical pickup device having same and information writing/reading device having same

An optical pickup device has a semiconductor laser emitting light which is in turn branched via a diffraction grating into at least three beams of light including a main beam and two sub beams which are in turn condensed via an objective lens on an optical disk at a guide groove and reflected by the optical disk to provide three reflections of light which are in turn received by detectors, each divided into two regions, respectively, to generate a tracking error signal. The diffraction grating is divided into three regions including a first region, a second region and a third region located intermediate therebetween, each having a periodical structure out of phase, the periodical structure having grating grooves in a direction determined depending on the phase of the second region to incline relative to a direction perpendicular to the guide groove of the optical disk.

Optical pickup device recording and/or reproducing information on and/or from a plurality of kinds of recording media

An optical pickup apparatus and a drive apparatus having the same are provided. Second light-receiving elements or third light-receiving elements for receiving &#xb1;first-order diffraction light beams from a polarization hologram are arranged outwardly of a circular region having the optical axis of a zero-order diffraction light beam on a light detector as its center, a radius of which is expressed by (2&#xd7;t/n)&#xd7;(f/f), where fdenotes a focal length of an objective lens, fdenotes a focal length of a coupling lens, t denotes a maximum value of a light transmitting layer thickness, n denotes a refractive index of a light transmitting layer.

Optical pickup apparatus and drive apparatus having the same

There is provided an optical pickup apparatus that can obtain a stable servo signal by reducing stray light generated by diffraction in a recording layer other than a recording layer on which light is condensed. A hologram element provided in an optical pickup apparatus for recording information onto a recording medium and/or reproducing information on the recording medium by use of light includes fourth and fifth divisions where at least first-order diffracted light among diffracted light beams obtained by reflection and diffraction on a recording layer other than a light-condensed recording layer on which light is condensed by an objective lens so as not to be directed toward first and second light-receiving elements for detecting focus position information and third to eighth light-receiving elements for detecting track position information.

Optical pickup apparatus

An optical pickup includes a hologram element. The hologram element is provided with a hologram pattern including a splitting section for focus which splits light used for the detection of an FES and a splitting section for tracking which splits light used for the detection of a TES. The splitting section for tracking is formed in a region excluding a region interposed between a first virtual straight line and a second virtual straight line. The first virtual straight line is drawn on the hologram element in parallel to an X direction and passes through an optical axis of reflected light entering the hologram element in a state where the objective lens is in a neutral position, and the second virtual straight line is drawn in parallel to the first virtual straight line, while being spaced at a distance d from the first virtual straight line.

Optical pickup

An object of the present invention is to attain stable tracking servo performance by suppressing an offset caused by a shift of an object lens or a tilt of a disk, despite the one-beam method which does not cause reduction in light quantity of the main beam. A diffraction grating is provided between a hologram and a light receiving section, and a diffraction efficiency of the diffraction grating is varied in a grating longitudinal direction. For example, if an incident light beam on the diffraction grating is shifted in the grating longitudinal direction, the quantity of received light in each light receiving section varies to cause offset. By performing tracking servo so as to cancel the change, it is possible to correct the offset, thereby attaining stable tracking servo performance.

Light integration unit, optical pickup device using the unit, and optical disk device

An optical pickup converts a laser beam from a semiconductor laser () into a parallel ray with a collimator lens (), and divides it into a main beam (), a sub-beam (+1st order component) (), and a sub-beam (&#x2212;1st order component) () with a gradient multiple-division type phase difference grating (). After passing through a beam splitter (), an objective lens () condenses the light beams on a track () of an optical disc (), and the reflected light that has passed through the objective lensis reflected at the beam splitter () and is guided into optical detectors (A,B, andC) by a condensing lens (). Accordingly, in a tracking error signal detecting method using the push-pull signals of the main beam and sub-beams, an offset produced by an objective lens shift or a disc tilt can be cancelled at low cost without lowering the efficiency of using light.

An optical pickup device includes a detection-use condenser lens for focusing a reflected light from a disk of a light emitted from a light source; a hologram element for dividing a light passed through the detection-use condenser lens into a light passed through a high numerical aperture region and a light passed through a low numerical aperture region; and a photodetector including at least a first light receiving element for detecting the laser beam which passed through the high numerical aperture region and a second light receiving element for detecting the laser beam which passes through the low numerical aperture region. Based on output signals from the first light receiving element and the second light receiving element, a focus error signal FEand a focus error signal FEare prepared respectively. According to an output value of the photodetector, a focus control is performed based on the error signal FEor the focus error signal FE

Optical pickup device and focus control method

Laser beam irradiation spots are formed in a delta arrangement on a defective pixel present in a liquid crystal panel so that liquid crystal molecules in areas surrounding the irradiation spots are oriented vertically. Alternatively, an aligning film in a defective pixel is irradiated with a laser to form minute grooves in a different direction than the rubbing direction of the aligning film, whereby the orientation of the liquid crystal is changed so that the liquid crystal between the aligning films is no longer twisted. Thereby, a defective pixel present in a liquid crystal display panel can be made inconspicuous, and as a result, degradation of the display quality of the liquid crystal display device after correction can be prevented.

Method for the correction of a defect in a liquid crystal display device

A defect compensation method for smoothing a surface of a transparent plate by radiating an ArF excimer laser beam to a defect at the surface. The ArF excimer laser beam is radiated by use of a mask having an opening which is shaped in accordance with the shape of the defect, through a lens, or while the size of the beam at the defect is changed to a plurality of values. As the mask, an iris mask having an opening which is larger than the defect is usable. The size of the beam is changed by exchanging, a plurality of masks each having an opening of a different size from one another, or by use of a mask having a plurality of openings of different sizes. Alternatively, the ArF excimer laser beam is radiated so as to have an energy which is high at a center and low at a periphery of the defect. Or, the ArF excimer laser beam has a smaller size than the size of the defect, and the transparent plate having the defect is moved so as to allow different portions of the defect to be irradiated sequentially by the ArF excimer laser beam and simultaneously the number of shots of the ArF excimer laser beam is changed.

Growing community of inventors

Soraku-gun, Japan

Osamu Miyazaki