Panasonic Corporation

Sony Corporation

Matsushita Electric Industrial Co., Ltd.

Tdk Corporation

Joji Anzai

Yoshiaki Komma

Yasumori Hino

Hideki Aikoh

Masahiko Tsukuda

Eishin Mori

Kousei Sano

Fumitomo Yamasaki

Akihiro Arai

Takayuki Nagata

Hiroyasu Inoue

Takashi Kikukawa

Koji Mishima

Jun Nakano

Hideki Hayashi

Osamu Kajino

Manami Miyawaki

Shigeki Takagawa

Shin-ichi Kadowaki

Kenji Narumi

Akira Kurozuka

Hideki Nakata

Takashi Nishihara

Takeharu Yamamoto

Shinichi Kadowaki

Morio Tomiyama

Takeshi Shimamoto

Yuuko Tomekawa

Keisuke Fujimoto

Masanari Mohri

Naohiro Kimura

Akihiro Yasuda

Haruhiko Habuta

Makoto Takashima

Kenichi Shinotani

Shape-wise thicknesses of a cover layer and first through (N&#x2212;1)th intermediate layers of an optical recording medium having refractive indexes nrnrare converted into thicknesses ttof the respective layers having a predetermined refractive index which makes a divergent amount equal to a divergent amount of a light beam resulting from the thicknesses trtra difference DFF between the sum of a thickness 'ti' through a thickness 'tj', and the sum of a thickness &#x201c;tk&#x201d; through a thickness &#x201c;tm&#x201d; is set to 1 &#x3bc;m or more (where i, j, k, and m are each any positive integer satisfying i&#x2266;j&#x3c;k&#x2266;m&#x2266;N), and the thicknesses ttare calculated by products of a function f(n) expressed by the following formula (1), and the thicknesses trtr()=&#x2212;1.0886.1027&#x2212;12.042&#x2003;&#x2003;(1)

Manufacturing method for optical recording medium, optical recording medium, optical information device, and information reproducing method

Shape-wise thicknesses of a cover layer and first through (N&#x2212;1)th intermediate layers of an optical recording medium having refractive indexes nr, nrare converted into thicknesses t, tof the respective layers having a predetermined refractive index which makes a divergent amount equal to a divergent amount of a light beam resulting from the thicknesses tr, tr, a difference DFF between the sum of a thickness 'ti' through a thickness 'tj', and the sum of a thickness &#x201c;tk&#x201d; through a thickness &#x201c;tm&#x201d; is set to 1 &#x3bc;m or more (where i, j, k, and m are each any positive integer satisfying i&#x2266;j&#x3c;k&#x2266;m&#x2266;N), and the thicknesses t, tare calculated by products of a function f(n) expressed by the following formula (1), and the thicknesses tr, tr()=&#x2212;1.0886.1027&#x2212;12.042+9.1007&#x2003;&#x2003;(1)

An optical recording medium having three or more information recording layers reduces crosstalk caused by multi-reflected beams and improves signal quality. In the optical recording medium having three or more information recording layers, the refractive index of a plurality of intermediate layers disposed between adjacent information recording layers is greater than the refractive index of a cover layer disposed between a light incident surface and an information recording layer being the closest from the light incident surface.

Optical recording medium and method for manufacturing the same

When information is recorded or reproduced on or from an optical information medium having three or more recording layers using blue light, interference by another layer light is reduced and, when information is reproduced from an optical information medium using red light, an S/N ratio is held excellently high. An optical head device includes a first laser light source () which emits blue light, a second laser light source () which emits red light, an objective lens () which focuses the blue light onto a recording layer of a first optical disc () or focuses the red light onto a recording layer of a second optical disc (), a photodetector () which receives the blue light reflected by the recording layer of the first optical disc () or the red light reflected by the recording layer of the second optical disc () and outputs an electric signal in accordance with an amount of the received blue light or red light, and a wavelength selective light blocking region () which blocks a predetermined range of the blue light including an optical axis thereof to prevent the predetermined range from reaching the photodetector (), and transmits the red light.

Optical head device, optical information device, and information processing device

An optical recording medium and an optical information device that improve the quality of a servo signal and a reproduction signal. In the optical recording medium, when shape-wise thicknesses tr, tr, tr, and trof a cover layer (), a first intermediate layer (), a second intermediate layer (), and a third intermediate layer () are respectively converted into thicknesses t, t, t, and tof the respective corresponding layers each having a predetermined refractive index 'no', a defocus amount with respect to a layer having a refractive index nr&#x3b1; and a thickness tr&#x3b1; (satisfying: 1&#x2266;&#x3b1;&#x2266;n (where &#x3b1; is a positive integer and n is an integer of 4 or more)), and a defocus amount with respect to a layer having the refractive index 'no' and a thickness t&#x3b1; (satisfying: 1&#x2266;&#x3b1;&#x2266;n (where &#x3b1; is a positive integer and n is an integer of 4 or more)) are equal to each other. Further, the thicknesses t, t, t, and tsatisfy |t&#x2212;(t+t+t)|&#x2267;1 &#x3bc;m, a difference between any two values of the thicknesses t, t, t, and tis set to 1 &#x3bc;m or more, and |(t+t)&#x2212;(t+t)|&#x2267;1 &#x3bc;m.

Optical recording medium, and optical information device

The recording/reproducing quality of a multilayer optical information recording medium deteriorate not only due to interference from other layers caused by light converging on other information layers but also due to stray light converging on the surface of a protective layer and stray light that does not converge on other information layers but rather returns to an optical head through the same optical path as the reproducing signal. The thickness composition of intermediate layers (, and) and the protective layer () in a four-layer optical information recording medium are set so as to eliminate the influence of interference caused by stray light from other layers reflected up to three times.

Optical information recording medium

An optical recording medium includes a cover layer, a plurality of recording surfaces, and a plurality of intermediate layers. The thicknesses of the layers are specifically determined and set at values which suppress a back focus problem. Because the optical recording medium suppresses back focus, the recording and reproducing of information using the optical recording medium is not obstructed.

An optical recording medium (disk) capable of preventing a back focus at a face thereof and reducing the interference between beams reflected by each recording surface, thereby improving a quality of a servo signal and a reproductive signal. In a disk having (N&#x2212;1) layers, if N is a natural number (more than three), and if a cover-layer thickness and intermediate-layer thicknesses are d, d, . . . dN, then a difference of 1 &#x3bc;m or above is set between the sum of di to dj and the sum of dk to dm for arbitrary natural numbers i, j, k, m (i&#x2266;j&#x2266;k&#x2266;m&#x2266;N). If refractive indexes are different from a standard value or different for each layer, then the thickness of each layer is converted based on a spread width of light according to the thickness.

Optical recording medium, manufacturing method for optical recording medium, information recording/reproducing method and information recording/reproducing device

A thermosensitive recording printer is provided with semiconductor lasersto, a polygon mirrorfor condensing laser light emitted from the semiconductor lasertoas condensed spots on a recording mediumto perform scanning in a main scanning direction, and a control unitfor controlling the output of the laser light. If a ratio of a spot diameter Dof the condensed spots in the main scanning direction and a spot diameter Din a sub scanning direction satisfy a relationship of D/D&#x2266;&#xbd; at the time of forming an image composed of a plurality of pixels on the recording mediumusing laser light, high-speed thermosensitive recording and a recording method with an uncomplicated power control are realized without reducing the power density of the condensed spots.

Optical disc label printer, thermosensitive recording printer and thermosensitive recording method

An object of the invention is to provide an optical element for use in an optical information recording and reproducing device or a like device for recording or reproducing information with respect to an information recording medium using laser light, wherein the optical element is a resin optical element capable of suppressing lowering in transmittance due to deterioration by irradiation of light having a high energy density, and maintaining a high transmittance for a long time. To realize the above object, used is an optical element made of a silicon resin cured material obtained by subjecting a silicon resin composition containing a silsesquioxane compound to a curing treatment.

Optical head, optical information recording and reproducing device, and optical information system device

An object of the invention is to provide an optical recording medium and a method for producing an optical recording medium that enable to improve the quality of a servo signal and a reproduction signal. The optical recording medium satisfies: t&#x2212;t&#x2267;1 &#x3bc;m, t&#x2212;t&#x2267;1 &#x3bc;m, t&#x2267;10 &#x3bc;m, and t&#x2212;(t+t+t)&#x2267;1 &#x3bc;m, where tis a thickness between a surface of the optical recording medium, and the first information recording surface, tis a thickness between the first optical recording surface and the second information recording surface, tis a thickness between the second optical recording surface and the third information recording surface, and tis a thickness between the third optical recording surface and the fourth information recording surface.

Optical recording medium, and method for producing optical recording medium

Shape-wise thicknesses of a cover layer and first through (N&#x2212;1)th intermediate layers of an optical recording medium having refractive indexes nr, nrare converted into thicknesses t, tof the respective layers having a predetermined refractive index which makes a divergent amount equal to a divergent amount of a light beam resulting from the thicknesses tr, tr, a difference DFF between the sum of a thickness 'ti' through a thickness 'tj', and the sum of a thickness &#x201c;tk&#x201d; through a thickness &#x201c;tm&#x201d; is set to 1 &#x3bc;m or more (where i, j, k, and m are each any positive integer satisfying i&#x2266;j&#x2266;k&#x2266;m&#x2266;N), and the thicknesses t, tare calculated by products of a function f(n) expressed by the following formula (1), and the thicknesses tr, tr:()=&#x2212;1.0886.1027&#x2212;12.042+9.1007&#x2003;&#x2003;(1)

An optical recording medium is provided having a plurality of laminated recording layers, wherein the recording layers are formed such that a spacing between each pair of recording layers of all recording layer combinations selected from the plurality of recording layers is different from that of each other pair. Accordingly, a return of lights reflected by other layers to an optical head along the same optical path as reflected light from a readout layer during the reproduction can be avoided. Therefore, use of the optical recording medium, from which a good reproduction signal can be obtained, can suppress a deterioration of a servo signal and a reproduction signal of a reproducing device due to a variation of interference fringes on a light receiving element.

Optical recording medium and reproducing device

Shape-wise thicknesses tr, tr, . . . , and trN of a cover layer and first through (N&#x2212;1)-th intermediate layers of an optical recording medium having refractive indexes nr, nr, . . . , and nrN are converted into thicknesses t, t, . . . , and tN which are calculated by products of a function f(n)=&#x2212;1.088n+6.1027n&#x2212;12.042n+9.1007 where n=nr, nr, . . . , and nrN.

An object of the invention is to provide an optical recording medium and an optical information device that enable to improve the quality of a servo signal and a reproduction signal. In the case where shape-wise thicknesses tr, tr, tr, and trof a cover layer, a first intermediate layer, a second intermediate layer, and a third intermediate layer are respectively converted into thicknesses t, t, t, and tof the respective corresponding layers each having a predetermined refractive index 'no', a defocus amount with respect to a layer having a refractive index nr&#x3b1; and a thickness tr&#x3b1; (satisfying: 1&#x2266;&#x3b1;&#x2266;n (where &#x3b1; is a positive integer and n is an integer of 4 or more)), and a defocus amount with respect to a layer having the refractive index 'no' and a thickness t&#x3b1; (satisfying: 1&#x2266;&#x3b1;&#x2266;n (where &#x3b1; is a positive integer and n is an integer of 4 or more)) are equal to each other; and the thicknesses t, t, t, and tsatisfy |t&#x2212;(t+t+t)|&#x2267;1 &#x3bc;m, a difference between any two values of the thicknesses t, t, t, and tis set to 1 &#x3bc;m or more in any case, and |(t+t)&#x2212;(t+t)|&#x2267;1 &#x3bc;m.

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Osaka, Japan

Joji Anzai