Industrial Technology Research Institute

Hung-Lu Chang

Der-Ray Huang

Tzu-Ping Yang

Tzuan-Ren Jeng

Jau-Jiu Ju

Jung-Po Chen

Po-Fu Yen

Ming-Feng Ho

Wen-Hsin Yen

An optical recording medium includes a) a dielectric layer, b) a recording layer, and c) a reflective layer, which are stacked on a surface of a substrate in the described order or stacked on the surface in the order of b) the recording layer, a) the dielectric layer, and c) the reflective layer. The recording layer contains a mixed nickel oxides which decomposes to release a gas and becomes transparent upon heating.

Write-once optical recording medium

This invention relates to a method for detecting and compensating the disk tilt of an optical disk and an apparatus using it. The disk tilt causes the coma which degrades the carrier-to-signal ratio of a pickup. To reduce the coma induced by the disk tilt of an optical disk, the pickup of the present invention adapts a two-dimension (2-D) grating to produce a plurality of laser beams for detecting the disk tilt in the radial and tangential direction of the optical disk. In addition, according to the radial and tangential tilts of the disk, an actuation device adjusts a reflection angle of a reflective mean to change the incident angles of the laser beams for the compensation of the coma induced by the disk tilt of the optical disk.

Method for detecting and compensating disk tilt and apparatus used it

A bifocal optical pickup head is disclosed for use in a optical pickup apparatus having a single objective lens, for generating two different focuses (bifocus) to access a compact disc (CD) and a digital versatile disc (DVD), which the thickness is different. When a beam passes through an optical element disclosed in the present invention, numerical aperture is controlled and spherical aberration is reduced by the optical element due to variations in optical path and radius. Therefore, after beams having different numerical apertures are focused by an objective lens, various focuses can be obtained.

Bifocal optical pickup head

The present invention is an optical pick-up head with a single objective lens, which discloses an optical pick-up head that can retrieve data from CD and DVD with different thickness using a single objective lens and a special optical element on the optical path of the optical pick-up head. This optical element is a three-beam grating which is formed a reflective film thereon, for example, by coating a metal or dielectric layer to achieve the goal of controlling the numerical aperture. Thus, this invention provides a single objective lens optical pick-up head with simple structure, low cost, easy assembling, and applications to multi-wavelength systems.

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Taichung, Taiwan

Hung-Lu Chang