Pioneer Corporation

Pioneer Electronic Corporation

Takayuki Nomoto

Takanori Maeda

Ikuya Kikuchi

Takuma Yanagisawa

Hiroshi Nishiwaki

Fumihiko Yokogawa

Junichi Furukawa

Seiichi Ohsawa

Mitsuru Sato

Kazuo Takahashi

Yasumitsu Wada

Akinori Ohkubo

An optical element includes a first microlens array unit and a second microlens array unit in each of which a plurality of microlenses are arranged. The first and second microlens array units are arranged opposite to each other with a distance which is longer than a focal length of the microlenses arranged in the first microlens array unit. The first microlens unit is arranged on a light-incident side with respect to the second microlens array unit. The interval between the microlenses arranged in the second microlens array unit is narrower than the interval between the microlenses arranged in the first microlens array unit. The optical element can appropriately suppress the occurrence of excessive pixel bright spot.

Optical element, head-up display and light source unit

An optical element includes first and second microlens array units on which microlenses are arranged. The microlenses are formed by lens contour having a polygonal shape in a plan view. The first and second microlens array units are arranged opposite to each other at a position where a distance between the first and second microlens array units is at least longer than a focal distance of the microlens, and are formed so that a direction of vertices of the lens contour of the microlens arranged on the first microlens array unit is different from a direction of vertices of the lens contour of the microlens arranged on the second microlens array unit. According to the above optical element, it is possible to appropriately suppress an influence of shift of the position between the first and second microlens array units, and it becomes possible to produce the optical element with ease.

Optical element, head-up display and method for producing optical element

There is provided a type judgment device capable of rapidly and safely identifying the type of an optical disc while preventing unexpected information recording or information erase. An optical beam as parallel light is applied in a circular polarized state to an optical disc having recording tracks and the polarization characteristic in the reflected light is detected. According to the detected polarization characteristic, the type of the disc is judged in accordance with the interval of the adjacent recording tracks.

Kind identifying apparatus, kind identifying method, and identifying program

A detection signal Soutputted from a light reception unit (A) of detection elements () formed by four-division light reception element is added to a detection signal Soutputted from a light reception unit (D) so as to obtain an addition signal Sand a phase difference signal Pindicating the phase difference between the addition signal Sand the detection signal SFurthermore, a phase difference signal Pindicating the phase difference between the addition signal Sand the detection signal Sis obtained. The phase difference signal Pis subtracted from the phase difference signal Pso as to generate a tracking error signal TE

Tracking error signal generation device and tracking error signal generation method

An optical disc includes an information recording layer having a record of information as a pit train with a predetermined track pitch and a light-transmissive layer formed on the information recording layer so that the information can be reproduced by a beam of light illuminated through the light-transmissive layer to the information recording layer by an objective lens. The optical disc includes a feature in that a relationship of 0.194(&#x3bb;/NA)&#x2266;TP &#xd7;Tmin&#x2266;0.264(&#x3bb;/NA)is satisfied, provided that the track pitch is TP, a pit shortest length is Tmin, a wavelength of the light beam is &#x3bb; and a numerical aperture of the objective lens is NA. The optical disc also includes a feature in that a pit width is 120 nm or smaller in a range of a track pitch of 0.280 to 0.325 &#x3bc;m.

High density optical recording medium and method for reproducing thereof

A tracking servo apparatus in which reflection light obtained when a laser beam is irradiated onto a recording surface of an optical disc is photoelectrically converted, thereby obtaining a photoelectric conversion signal, a tracking error signal showing a deviation amount of an irradiating position of said laser beam for a track in a disc radial direction on the recording surface is generated by the photoelectric conversion signal, a spherical aberration occurring in an optical system is detected, a level of the tracking error signal is corrected on the basis of the detection result, and the irradiating position of the laser beam is moved in the disc radial direction in accordance with the level-corrected tracking error signal.

Tracking servo apparatus of optical information recording and reproducing apparatus

A system for detecting a tracking error comprises a two-divided type light detector (), LPFs (), first and second waveform generator (), first and second delay circuits (), first and second adders () and a phase comparator (). The detector () has two photo detecting elements () disposed separately in the radius direction of an optical disc. The LPFs () remove high frequency components from the outputs of the elements (). The first waveform generator () generates a sine wave (B) with amplitude corresponding to the output level of a signal (A), which passed the LPF (). The second waveform generator () generates a sine wave (B) having the identical frequency to the wave (B), with amplitude corresponding to the output level of a signal (A), which passed the LPF (). The first delay circuit () delays the wave (B) by the prescribed amount of delay to form a sine wave (C). The second delay circuit () delays the wave (B) by the same amount of delay as the wave (B) to form a sine wave (C). The first adder () adds a signal of the wave (B) to a signal of the wave (C) to output the first added signal (D). The second adder () adds the signal of the wave (B) to a signal of the wave (C) to output the second added signal (D). The phase comparator () compares the first added signal (D) with the second added signal (D).

System and method for detecting tracking error

A tracking control circuit includes a light receiving element divided in at least four sections. Of these, a group of divided light receiving sections located on a diagonal line obtains a first differential signal. A group of divided light receiving sections located on another diagonal line obtains a second differential signal. In accordance with the phase difference between the first and second differential signals, a tracking error signal is generated to make tracking control on a wobbled information recording track.

Tracking control circuit for tracking a wobbling track formed on an optical recording medium

An optical pickup device has one or a plurality of aperture restriction devices that are disposed in the optical path of a light beam that is emitted from a light source and illuminated onto an optical disk. The aperture restriction device restricts the cross-sectional shape of the light beam corresponding to the aperture in the time axis direction in comparison to that corresponding to the aperture in the radial direction and restricts the light beam in the radial direction of the optical disk by a pair of first partial arcs.

Optical pickup device having aperture restriction arrangement

An optical disk has a recording layer recording information as a row of marks and non-marks alternately appearing in a groove formed at a track pitch of 0.280 &mgr;m or greater and a light transmissive layer formed over the recording layer, to reproduce information due to a light beam having a wavelength in a range of 375 nm to 415 nm and illuminated by an objective lens having a numerical aperture NA in a range of 0.80 to 0.90 through the light transmissive layer to the recording layer. The groove has a depth in a range of 18 nm to 32 nm.

Optical disk

An optical disk includes: an information recording surface on which a laser light is irradiated; and information pits arranged on the information recording surface and including a plurality of shapes each corresponding to information to be recorded, each of the shapes having different lengths in at least one of a radial direction of the disk and a circumferential direction of the disk and a depth d substantially satisfying the following relationship with a wavelength .lambda. of the laser light:

Optical disk having information pits of different lengths and shapes

An optical disk includes: an information recording surface; first surface-transformed portion array formed on the information recording surface and including first surface-transformed portions transformed in shapes, the first surface-transformed portion reflecting a laser light, when it is irradiated thereon, polarized in accordance with the transformed shape thereof so that major axis of the polarized light is oriented to a first direction; and second surface-transformed portion array formed on the information recording surface and including second surface-transformed portions transformed in shapes, the second surface-transformed portion reflecting a laser light, when it is irradiated thereon, polarized in accordance with the transformed shape thereof so that major axis of the polarized light is oriented to a second direction. The first surface-transformed portion array and the second surface-transformed portion array are formed alternately in a radial direction of the optical disk, and the first direction and the second direction differ from each other by 45 degrees.

Optical disk and apparatus for reproducing the same

An optical disk includes: information recording surface on which information is recorded by irradiating laser light, the information being readable based on the laser light reflected by the information recording surface; and surface transformed portion, arranged on the information recording surface, on which a plurality of transformed shapes each corresponding to the information are formed so that polarization conditions of the laser light reflected by the transformed shapes differ according to the information.

Polarization of a reflected light beam is changed according to the depth

Disclosed is an optical disk having at least one pit in each of unit areas continuously provided in a circumferential direction of the disk, said pit having a depth of at least one of n depths (n: an integer equal to or greater than 2). Also disclosed is an information reproducing method of reproducing pit information from such an optical disk. This method comprises the steps of irradiating a read beam having frequency components of n wavelengths corresponding to four times the n depths to a row of the unit areas, and acquiring pit information based on an intensity distribution in a plane perpendicular to the optical axis of a reflected beam from the row of unit areas.

Optical information reproducing system with a reading beam having

An optical disk is provided, on which a light spot is formed by projecting a light beam to optically reproduce information recorded on the optical disk by receiving a light from the light spot by use of a photodetector having two divided light receiving surfaces. The optical disk includes: a disk-shaped information recording member having an information recording surface; a track formed on the information recording surface, disposed along a circular direction of the optical disk, and having track pitch smaller than the diameter of the light spot; and a plurality of pits arranged on the track and modulated by the information recorded on the information recording surface. The pits have parameters determined as functions of the wavelength, the numerical aperture, and the track pitch such that the light from the light spot covering two adjacent turns of the track is detected to be a DC component signal by one of the two divided light receiving surfaces of the photodetector.

Growing community of inventors

Tsurugashima, Japan

Takayuki Nomoto