Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Panasonic Intellectual Property Management Co., Ltd.

Agency of Industrial Science and Technology

Hidemi Takahashi

Yasushi Ueda

Makoto Okazaki

Yukio Iijima

Nobuaki Minakuchi

Reiji Sano

Minoru Kimura

Yasuyuki Morita

Yuji Maruyama

Hidehiko Kawakami

Atsuharu Yamamoto

Hideaki Kawamura

Katsuya Watanabe

Yoshikazu Kawauchi

Naohiro Kimura

Tetsuya Shihara

Hiroshi Naito

Yuka Hasegawa

Masaaki Nakashima

Yukio Sugimura

The error correction processing includes: data reproduction processing of reproducing recording data, constituted by a plurality of data units each made of a plurality of bits, from a recording medium sequentially; error correction processing of performing error correction in the row direction and error correction in the column direction at least once for an error correction code block that has the reproduced recording data arranged in the row direction over a plurality of rows; determination processing of determining whether uncorrectable data is left behind after execution of the error correction processing; and erasure correction processing of performing, when it is determined that uncorrectable data is left behind, column-direction error correction considering data constituting at least one row of the error correction code block as erasure data, even in cases where uncorrectable data in the error correction in the row direction is not left behind.

Error correction method and data reproduction device

An optical disc recording and reproducing apparatus for recording and reproducing data in and from an optical disc by the use of the optical disc as a recording medium, comprises analog processing means including a binarization unit for subjecting a signal read from the optical disc to binarization and a servo unit for controlling recording and reproducing a signal in and from the optical disc; synchronous clock generating means for generating a synchronous clock signal which is synchronized with the signal read from the optical disc; address detecting means for detecting address information indicating a physical position on the optical disc based on the signal read from the optical disc, and outputting a signal indicating the address information and a signal indicating that the address has been detected when the address information has been detected; a sector counter for holding a sector count value of a sector as a recording unit on the optical disc, and updating the sector count value according to the synchronous clock signal and the signal output from the address detecting means; and gate signal generation switching means for generating gate a signal which controls the analog processing means, based on one of the sector count value held in the sector counter and information obtained from the analog processing means, according to the signal indicating that the address has been detected, which is output from the address detecting means.

Optical disc recording and reproduction apparatus having automatic gate signal generation modes

Optical disc recording and reproduction apparatus

It is a subject to provide an optical disc device which can speedily control generation of a data sync clock, when the position of data reading by an optical pickup shifts between a data unrecorded area and a data recorded area. An optical disc device comprises a first wobble cycle counterfor counting the cycle of a wobble reference signal Sthat is synchronized with a wobble signal Sobtained from an optical disc, with a constant cycle clock S; a second wobble cycle counterfor counting the cycle of the wobble reference signal Swith a data sync clock S; a count value comparatorfor obtaining a difference between a count value outputted from the first wobble cycle counterand a count value outputted from the second wobble cycle counter; and a comparison result judgement unitfor judging whether or not the value of a count value comparison result that is output from the count value comparatoris within a range of preset values. Therefore, when a position where information is read by an optical pickup shifts between a data unrecorded area and a data recorded data, generation of the data sync clock can be speedily controlled.

Optical disk device

Optical disc recording and reproducing apparatus having automatic gate signal generation modes

An optical disk apparatus of the present invention includes: a light amount detection section for irradiating an information carrier with a light beam so as to detect information recorded in a data section of the information carrier, wherein the information carrier includes the data section and an address section associated with the data section, the data section is an information track formed by a land or a groove where information can be recorded or reproduced, and the address section contains address information corresponding to the information track which is recorded in the address section by one or more concave or convex pit offset by a predetermined distance from a center of the information track; an address polarity determination section for determining whether the address section over which the light beam has passed is either on an outer periphery side or on an inner periphery side with respect to the center of the information track being scanned by the light beam, based on a signal output from the light amount detection section; an address reproduction section for reproducing the address information recorded in the address section based on a signal output from the light amount detection section; and an address confirmation section for confirming the data section from which or to which data is to be reproduced or recorded, based on the determination result from the address polarity determination section and the address information reproduced by the address reproduction section.

Optical disk apparatus with address polarity determination and confirmation

An inspection apparatus for inspecting a wiring pattern on a printed board by illuminating the printed board with light to photoelectrically convert light reflected from the printed board into an optical grey level image corresponding to the wiring pattern thereon, the grey level image being converted into a bi-level image. The inspection apparatus includes a thinning circuit to perform a thinning process for removing the bi-level image by one picture element from the background side of the wiring pattern, the thinning process being repeatedly performed predetermined times with respect to all of picture elements of the wiring pattern to output the number of repetitions of the thinning process and further to output a skeleton image. Also included is a distance image converter to output a distance conversion image where the number of repetitions is given as a distance value from the background of the wiring pattern. The inspection apparatus compares the distance value of the distance conversion image with one or more thresholds along the skeleton image. This arrangement allows direct detection of the wiring pattern width, thereby permitting the wiring pattern inspection with a simple structure.

Apparatus for inspecting wiring pattern formed on a board

A pattern inspection system for inspecting a pattern of a land for a through-hole formed in a printed board. In the system there are included a first illumination device for optically illuminating the printed board, a second illumination device for illuminating the printed board with light modulated at a predetermined period and an image pickup responsive to reflection light and transmission light from the printed board due to the first and second illumination devices to photoelectrically convert the printed board into a gray level image. The gray level image is converted into a bi-level image by a bi-level conversion device and then converted into an edge image by an edge detecting device. The edge image is expanded and contracted by predetermined amounts so as to obtain a through-hole image corresponding to the through-hole. A defect detecting device detects a defect of the pattern of the printed board on the basis of the through-hole image and the bi-level image from the bi-level conversion device.

Pattern inspection system for inspecting defect of land pattern for

A thermally insulating casing accommodates an infrared ray sensing element. The casing has a window which conducts infrared ray to the sensing element. The window is covered with heat absorption gas. An infrared ray emitting element may be accommodated within the casing. The casing may have a second window which passes infrared ray generated by the emitting element. The second window may be covered with the heat absorption gas.

Infrared ray sensing device

Method and apparatus for measuring a distance to an object includes directing first and second laser beams having frequencies .omega..sub.11 and .omega..sub.12 toward the object. A first reference signal is derived having a beat frequency .omega..sub.1 =.omega..sub.11 -.omega..sub.12. A first reflected light beam reflected from the object is detected and has the beat frequency .omega..sub.1 and a first phase difference with respect to the first reference signal. The first phase difference is then extracted from the first reference signal and the first reflected light beam and a first plurality of distance nodes is calculated from the first phase difference. Then, the frequency of the second laser beam is changed to .omega..sub.13. A second reference signal having a beat frequency of .omega..sub.2 =.omega..sub.11 -.omega..sub.13 is then derived. A second reflected light beam reflected from the target is detected and has the beat frequency of .omega..sub.2 and a second phase different with respect to the second reference signal. The second phase difference is then extracted from the second reference signal and the second reflected light beam and a second plurality of distance nodes is then calculated from the second phase difference. Finally, the minimum distance node coincident between the first and second pluralities of nodes is selected as the distance to the object.

Distance measurement by laser light

In a laser resonator having a gas-introducing portion at one end of a laser tube, where the gas introducing portion comprises an inner tube communicating with the laser tube and an outer tube covering the inner tube. The inner tube has a plurality of circumferentially spaced apart flow passages so that a gas mixture fed from a gas source to an annular chamber defined between the inner surface of the outer tube and the outer surface of the inner tube, is led into the inside of the inner tube via the flow passages. As a result, turbulence occurs within the inner tube so that radial distribution of gas flow speed in the laser tube is made uniform, thereby increasing the maximum output and stability. The flow passages may be slits, oval or circular openings, triangular openings or the like. The flow passages may be skewed relative to both the radial and tangential lines passing therethrough or relative to the axis of the inner tube so that the gas introduced inside the inner tube spirals, and therefore the gas travels along the laser tube with a spiral movement.

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Osaka, Japan

Hidemi Takahashi