Taiyo Yuden Co., Ltd.

Keiichi Ida

Isao Matsuda

Mitsuo Sekiguchi

Ryuichi Sunagawa

Atsuo Shimizu

Yoshikazu Takagishi

Masatsugu Suzuki

Akihiko Mochizuki

Daisuke Morishita

Shoichiro Hirakuni

To provide an optical information recording medium including a pigment appropriate for high-density and high-speed optical recording by the blue laser light of 350 to 500 nm and especially around 400 nm (for example, 405 nm), enabling recording at low power, suppressing thermal affect of recording to the optical recording layer, and assuring a reflection ratio or modulation degree by the change of a refraction index n and an attenuation coefficient k; and to provide a recording method thereof. Instead of the recording based on the optical phase difference obtained by a change &#x394;n of the refraction index n of the pigment as in the conventional method, a pigment capable of performing recording based on the change ?k of the attenuation coefficient k has been obtained. Recording may be performed mainly by the change &#x394;k of the attenuation coefficient k. It is preferable to use a recording wavelength which is at the side of longer wavelength than the absorption peak of the absorption spectrum for the laser beam of the aforementioned pigment. However, the invention is not to be limited to this and characterized in recording performed by the change of the attenuation coefficient of the pigment against the recording wavelength.

Optical information recording medium and recording method thereof

An optical information recording medium, recording and reproducing method and device for same, and an optical pickup, which enables high-density recording and high-speed recording. Recording or reproduction is performed to or from the optical information recording medium having a track pitch Tp of 1.0 &#x3bc;m&#x2266;Tp&#x2266;1.2 &#x3bc;m, using laser light having a wavelength &#x3bb; of 770 nm&#x2266;&#x3bb;&#x2266;830 nm, and a spot diameter Sd of 1.1 &#x3bc;m&#x2266;Sd&#x2266;1.3 &#x3bc;m.

Optical information recording medium, method for recording/reproducing the same, and optical pickup

An optical information recording medium recordable at a high density two times or more higher than that of currently-used CD-Rs by optimally determining the thicknesses of a recording layer and a reflecting layer. The optical information recording medium comprises the recording layer formed on a transparent substrate having a spiral pregroove formed thereon, wherein a track pitch Tp of the pregroove is 1.0 &#x3bc;m&#x2266;Tp&#x2266;1.2 &#x3bc;m and a thickness Dg of the recording layer on the pregroove is 80 nm&#x2266;Dg&#x2266;120 nm.

Optical information recording medium

An optical information recording medium recordable at a high density two times or more higher than that of currently-used CD-Rs by devising the shape of a pregroove is provided. It is provided with a recording layer formed on a transparent substrate having a spiral pregroove formed thereon, wherein a track pitch Tp of the pregroove is 1.0 &mgr;m&lE;Tp&lE;1.2 &mgr;m and an inclination angle Ga of sidewalls of the pregroove is 30&deg;&lE;Ga&lE;70&deg;.

An ion sensor and an ion sensor plate provided with an ion sensitive membrane which is characterized in that the ion sensitive membrane contains a material constituting the dissociation equilibrium of Ag/X, and an excessive quantity of an ion sensitive material or an anion scavenger. A coated film of surfactant is provided at the inner face of the passageway communicating with the test liquid-measuring electrode so as to add the surfactant to the test liquid. The plasticizer is added at a ratio of 65 to 80% by weight. The atomic ratio of silver and halogen in the silver halide layer is set to at least 1.2. The particle diameter of the modified silver halide layer is set to at most 1 &mgr;m.

Growing community of inventors

Gunma, Japan

Keiichi Ida