Patent application number | Description | Published |
20080198730 | Optical head and apparatus for optically recording and reproducing information - An optical sensor has first light receiving surfaces having respective pentagonal or hexagonal shapes and being independent of each other, and second light receiving surfaces having respective hexagonal shapes and being independent of each other, third light receiving surfaces having respective hexagonal shapes and being independent of each other, fourth light receiving surfaces having respective hexagonal shapes and being independent of each other, and fifth light receiving surfaces having respective hexagonal shapes and being independent of each other. A relationship between a size of each of the light receiving surfaces and a diameter of respective one of light beams received by corresponding one of the light receiving surfaces is set within a predetermined range. A light beam multiple-dividing element diffracts the light beams received by a first grating area to form +primary lights, and diffracts the light beams received by second and third grating areas to form +primary lights and −primary lights. Relationships of U/D and V/D are set within predetermined ranges. | 08-21-2008 |
20080219119 | Optical pickup and optical disc unit - Provided is an optical pickup which can eliminate a problem of causing a focus error signal and a tracking error signal to fluctuate due to interference of a signal light beam with a return light beam from another recording surface of a multi-layer optical disc during reproduction, | 09-11-2008 |
20080285420 | Optical Pickup and Optical Drive - An optical pickup including a two-wavelength multilaser for generating a tracking error signal and a focusing error signal with high accuracy without light quantity variations which otherwise might be caused by the interference. An optical beam of first wavelength is emitted from first laser light source, and an optical beam of second wavelength longer than the first wavelength is emitted from second laser light source. The optical beams of the first and second wavelength are each split into at least one main optical beam and two sub-optical beams by a grating having, in a single plane, a first grating pattern area for splitting the optical beam of the first wavelength and a second grating pattern area for splitting the optical beam of the second wavelength. The area of the first grating pattern area is larger than the area of the second grating pattern area. | 11-20-2008 |
20080298208 | OPTICAL HEAD AND OPTICAL DISC APPARATUS - An optical head includes semiconductor lasers for 455 nm, 655 nm, and 785 nm bands; a polarization change element and a polarizing beam splitter for luminous flux with a wavelength of 455 nm band, a first collimation lens for converting luminous flux having passed through the polarizing beam splitter into parallel flux, a first quarter-wave plate, a BD objective for focusing the flux onto a signal recording surface of BD, a first photo-detector for receiving light reflected by BD, a composite prism for reflecting flux reflected by the splitter and transmitting most of flux from the lasers for 655 nm and 785 nm bands, a second collimation lens for converting flux emitted from the composite lens into parallel flux, a second quarter-wave plate, an objective compatible with HD DVD, DVD, and CD; and a second photo-detector for receiving light reflected by HD DVD, DVD, and CD. | 12-04-2008 |
20090147661 | Optical Information Processing Apparatus, Optical Pick-Up Device And Optical Recording Disc System - An optical pick-up device includes a laser source enabling emission of at least two light beams with different wavelengths, an objective lens which focuses the light beams emitted from the laser source on an optical disc, an optical detector which receives a light reflected from the optical disc, a front monitor which receives a part of the light beams emitted from the laser source, a front monitor light-guiding plate which guides part of the light beams emitted from the laser source to the front monitor. The front monitor light-guiding plate is arranged between the laser source and the objective lens, at least a part of a region of the front monitor light-guiding plate illuminated by the light beams emitted from the laser source has a predetermined shape which causes the light beams to change traveling direction thereof by refraction and then be guided to the front monitor. | 06-11-2009 |
20090268584 | Optical Pickup Apparatus And Optical Disc Apparatus Using Same - An optical pickup apparatus is provided with a dividing element having a plurality of regions. The dividing element is capable of dividing a light flux reflected by the optical disc into a plurality of light fluxes having different outgoing directions. Each region of the dividing element and light receiving parts of a light detector are structured such that when a target information recording layer of the optical disc is brought into focus, a light flux reflected from the target information recording layer is focused on the light receiving parts of the light detector, and a light flux reflected from other information recording layer than the target information recording layer is not irradiated onto the light receiving parts of the light detector. | 10-29-2009 |
20100148045 | PHOTODETECTOR, DIFFRACTION GRATING, OPTICAL PICKUP AND OPTICAL DISC APPARATUS - The present invention provides a photodetector capable of generating highly accurate tracking and focusing error signals free of variations in light quantity caused by interference, in an optical pickup with a two-wavelength multilaser. The photodetector comprises first three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a first wavelength and second three light receiving areas arranged linearly to receive three light beams respectively resulting from splitting of a light beam emitted from a laser light source of a second wavelength longer than the first wavelength. The distance between both-end light receiving areas out of the first three light receiving areas is longer than the distance between both-end light receiving areas out of the second three light receiving areas. | 06-17-2010 |
20100214904 | Optical Pickup Having Radially Arranged Lenses in a Low Profile Construction - An optical pickup includes a first source which emits a first beam with a first wavelength; a second source which emits a second beam with a wavelength shorter than the first wavelength; a first collimate lens which collimates the first beam; a second collimate lens which collimates the second beam; a first objective lens which converges the first collimated beam onto an optical disc; and a second objective lens which converges the second collimated beam onto the disc. The first and second objective lenses are arranged in the disc radial direction. The second objective lens is arranged closer to the side of the disc outer circumference than the first objective lens. The first collimate lens is arranged on the right-hand side when the second objective lens is viewed from the first objective lens. The second collimate lens is arranged on the left-hand side when the first objective lens is viewed from the second objective lens. The gap between the first collimate lens and the first objective lens is larger than the gap between the second collimate lens and the second objective lens. | 08-26-2010 |
20110299378 | Optical Pickup Having Radially Arranged Lenses in a Low Profile Construction - An optical pickup includes a first source which emits a first beam with a first wavelength; a second source which emits a second beam with a wavelength shorter than the first wavelength; a first collimate lens which collimates the first beam; a second collimate lens which collimates the second beam; a first objective lens which converges the first collimated beam onto an optical disc; and a second objective lens which converges the second collimated beam onto the disc. The first and second objective lenses are arranged in the disc radial direction. The second objective lens is arranged closer to the side of the disc outer circumference than the first objective lens. The first collimate lens is arranged on the right-hand side when the second objective lens is viewed from the first objective lens. The second collimate lens is arranged on the left-hand side when the first objective lens is viewed from the second objective lens. The gap between the first collimate lens and the first objective lens is larger than the gap between the second collimate lens and the second objective lens. | 12-08-2011 |