Sony Corporation

Sony Disc & Digital Solutions Inc.

Sony Disc Technology, Inc.

Sony Disc & Digital Sloutions Inc.

Sony Corporation and Sony Disc Technology Inc.

Yoshitake Yanagisawa

Makoto Tsukahara

Akiya Saito

Yoshinobu Usui

Mitsuru Sato

Koichi Sato

Toshiyuki Kashiwagi

Jun Nakano

Tetsuhiro Sakamoto

Motohiro Furuki

Shigeki Ishizuka

Jiro Ikeda

Hideo Kawachi

Akira Nikami

Shin-Ichiro Tamura

Takayuki Asahina

Takao Murooka

Takashi Matsubara

Yoko Hayashi

Inho Cho

Shoji Fukuchi

In a process of manufacturing a disc master, a stamper, a disc substrate, and an optical disc, separation performance between the stamper and the disc substrate and maintenance of satisfactory signal characteristics after the optical disc is manufactured are taken into consideration in the step of manufacturing the disc master. In the disc master, a boundary portion between a recessed portion and a non-recessed portion includes a small protrusion which protrudes from a flat surface of the non-recessed portion. The shape of the disc master is inversely transferred to the stamper, and the shape of the stamper is inversely transferred to the disc substrate. The separation performance is improved and the signal characteristics are maintained due to the shape of the boundary portion.

Disc master, disc master manufacturing method, stamper, disc substrate, optical disc, and optical disc manufacturing method

An optical disc medium and corresponding optical recording method and optical recording apparatus. The optical disc medium comprises a substrate on which a shape according to modulated information data has been formed, and a coating film formed on the substrate. Known data is recorded in a predetermined location of the information data, with the known data being rewritten as postscript information by recording a postscript portion to the coating film to alter a portion of the known data, wherein the postscript information comprises readable non-error data.

Optical disc medium and data recording method and apparatus

An optical disk read only memory having an information recording surface with a concave-convex pattern formed on the basis of a first signal and a reflective film covering the surface. The disc medium includes: an additional information recording section formed on a recording track of a first data string; and a second data string including a mark of removing or reducing the reflective film. The modulation methods of the first and the second data strings are identical, and Lh(n)&#x3e;Lp(n) and Wh(n)&#x3e;(Wp(n)+Wp(n))/2 are satisfied, where a reference clock cycle is T, a data length is nT, a length and a width of the mark are Lh(n) and Wh(n), a length and a width of a base of the pit are Lp(n), and Wp(n), a length and a width of a top face of the pit is Lp(n) exceeding Lp(n), and Wp(n) exceeding Wp(n).

Optical disk read only memory

A molding and film forming apparatusmolds a disc substrate from a stamperformed from an optical disc disc-masterand forms a coating film, for example, a reflective film onto the disc substrate, thereby forming a recorded optical disc. A postscript apparatuswrites postscript information once onto an optical discformed by the molding and film forming apparatus. As postscript information, a laser beam is irradiated to a predetermined interval of the optical disc, a portion which is detected as a pit is formed, and an optical discon which postscript informationhas been recorded is formed. Identification information which enables each optical discto be identified can be postscribed. The postscript information is recorded in a conventional format and the postscript information can be reproduced by an existing reproducing apparatus.

Optical disk medium, and data recording method and device

A disc defect inspection apparatus which can detect a defect of a disc, such as an optical disc, with high accuracy. A disc defect inspection apparatus includes a rotating portion for rotating a disc, laser radiating optical portion for radiating laser lights on the disc rotated by the rotating portion under predetermined scanning conditions, sensors for detecting reflected laser lights from the disc, and a memory in which output signals of the sensors are stored together with address data generated in unison with the scanning of laser lights. Sensor outputs indicative of address positions of the disc are stored in the memory and sensor outputs near the address positions are read out and a defect of the disc is detected on the basis of a spatial difference among the nearby sensor outputs and the sensor output of the center address position.

Inspection apparatus for inspecting a defect of an optical disc

An optical recording medium capable of recording and/or reproducing an information by using a laser beam, comprising: a support layer having an information signal-recording portion on one side surface thereof on which said laser beam is incident, and a transparent layer disposed over the support layer and having a thickness smaller than that of the support layer. In accordance with the present invention, there are further provided production method for optical or magneto-optical discs whereby a high density reproduction can be achieved.

Optical recording medium and method of producing same

A disc defect inspection apparatus which can detect a defect of a disc, such as an optical disc, with high accuracy. A disc defect inspection apparatus includes a rotating portion for rotating a disc laser radiating optical portion for radiating laser lights on the disc rotated by the rotating portion under predetermined scanning conditions, sensors for detecting reflected laser lights from the disc, and a memory in which output signals of the sensors are stored together with address data generated in unison with the scanning of laser lights. Sensor outputs indicative of address positions of the disc are stored in the memory and sensor outputs near the address positions are read out and a defect of the disc is detected on the basis of a spatial difference among the nearby sensor outputs and the sensor output of the center address position.

Apparatus for detecting a defect of an optical disc based on sensor

The present invention is directed to an optical data storage medium in which a reflecting layer is formed on a substrate. A dye containing layer having a reflectivity of 15 to 25% is used as the reflecting layer, and a signal modulation degree of an information signal falls within a range of from 0.3 to 0.6. Further, a real number portion n of complex index of refraction of the reflecting layer is selected so as to satisfy n.gtoreq.1.84. According to the present invention, there is provided an optical data storage medium which can be reproduced by a recording and reproducing apparatus which is designed so as to record and reproduce a medium such as a magneto-optical disc or the like having a reflectivity of about 15 to 25%. Therefore, the recording and reproducing apparatus that can record and reproduce the medium having the reflecting layer whose reflectivity is low can be made small in size and light in weight.

Optical data storage media

An optical disc for use as a compact disc, an optical video disc, or the like has a disc substrate of a light-transmissive material such as polycarbonate, PMMA, or the like. The disc substrate has a pattern of pits and lands formed as representing an information signal on at least one surface thereof. A thin reflective layer of a-corrosion-resistant metallic material such as an alloy of Fe, Ni, and Co is deposited on the disc substrate over the pattern of pits and lands. The optical disc is relatively inexpensive to manufacture as no protective layer needs to be deposited on the reflective layer and is also highly resistant to loss of performance with aging because the reflective layer is made of a corrosion-resistant metallic material.

Growing community of inventors

Shizuoka, Japan

Yoshitake Yanagisawa