Sony Corporation

Kunika Hashimoto

Noriaki Nishi

Tadashi Okano

Masaru Tezuka

Naoki Inoue

Hiroshi Kiriyama

Haruyuki Kouno

An optical disk drive () for optically recording and/or reproducing information signals is provided in which the power of a light beam emitted from an optical head () to an optical disk () is controlled by an optical-coupling efficiency varying elements () correspondingly to the type of the optical disk, recording layer in a multilayer optical disk and a mode of operation selected while a variation of the optical-coupling efficiency is being detected by a light-detecting element (), thereby positively varying the optical-coupling efficiency in a minimum necessary time. Thus, the power of the light beam focused on the optical disk can be varied in a wide range without having to extremely raise the ratio in output power between modes of operation at a light source (). Therefore, even a light source whose rating of optical output power is small can be used to write and read information signals to and from any of optical disks of different types or to each of recording layers in a multilayer optical disk with a high accuracy. Namely, good characteristics in writing and reading information signals can be assured without having to largely vary the ratio in output power of the light source from the write to read mode, from one to another type of optical disks or from one to another recording layer of the multilayer optical disk.

Optical head, optical recording medium recording and/or reproducing apparatus and recording and/or reproducing method using the optical head

The present invention is directed to an optical head adapted for performing recording or reproduction of information signals with respect to an optical disc (), which controls light coupling efficiency with respect to light beams irradiated onto the optical disc () by light coupling efficiency adjustable element such as a liquid crystal element (), etc. in accordance with type of the optical disc (), recording surface of multi-layer optical disc and/or operation mode to change power of light beams irradiated onto the optical disc () to a large extent without excessively increasing change quantity of output power of a semiconductor laser element (). A beam splitter () divides incident light beams of P-polarized light at a predetermined ratio to allow the light beams thus obtained to be incident on a light detector () for disc surface power monitor.

Optical head and optical recording medium drive device

A photosensor detecting light-emission quantity from a light-emission lamp is set up, in order to regulate the current supplied with the light-emission lamp from a power according to a light-quantity detecting signal from the photosensor, so as to make the light-emission quantity from the light-emission lamp constant. Projected light-quantity onto a movie film is regulated and an image obtained from a shooting section becomes an image having a good quality with a little flicker.

Luminous source apparatus, image projecting apparatus and image projection converting apparatus

A luminous source apparatus, an image projecting apparatus, and an image projection converting apparatus to prevent a projected image, or an electronic image obtained through electronization of the projected image from intensity variations. A photosensor detects the light-emission quantity from a light-emission lamp in order to regulate the current supplied with the light-emission lamp according to a light-quantity detecting signal from the photosensor, so as to make the light-emission quantity from the light-emission lamp constant. Projected light-quantity onto a movie film is regulated and an image obtained from a shooting section becomes an image having a good quality with a little flicker.

A reel servo device employed in a recording and/or reproducing apparatus employing a tape cassette housing a tape as a recording medium includes an unusual running detection circuit for deciding if the tape housed within the tape cassette loaded on the tape recording and/or reproducing apparatus is wound in a slack winding state on a tape reel. If the tape running state is decided to be an unusual tape running state, tape tension data from the supply side tension arm is differentiated. If the differentiation data is positive indicating an increasing tape tension, the rewind side reel motor is controlled in a direction of slackening tape tension at the rewind tape reel side. Conversely, if the differentiation data is negative indicating an decreasing tape tension, the rewind side reel motor is torqued in a direction of tensioning the tape at the rewind tape reel side.

Growing community of inventors

Kanagawa, Japan

Kunika Hashimoto