Optical information recording and reproducing device

Abstract

Abstract PURPOSE:To erase the offset of a positional shift information such as a focus error signal, etc., with a light quantity distribution signal detected (mentioned in the following) by providing a light quantity distribution detecting means that detects the light quantity distribution in the tangential direction of a recording medium of a reflected light from a far field position of the recording medium. CONSTITUTION:For instance, on focus error signals SFE from the light receiving elements 9A, 9B of a light detector 9, the offset due to the irregularity in the light quantity distribution in the tangential direction of a reflected light from the recording medium is superposed. The light quantity distribution detecting means 31 consists of a light detector 33 in which light receiving elements 33C, 33D are disposed neighboring in the tangential direction at a far field position and an arithmetic circuit 34 to operates a differential signal C-D from an output CD, and outputs the differential signal C-D as a light quantity distribution signal Sd. An offset erasing means 32, for instance, comprises of an arithmetic circuit 35 to operate a differential signal SFE-Sd=(A-B)-(C-D), and outputs the differential signal SFE-Sd as a focus error signal S'FE from which the offset has already been erased.

Inventors

• 👤 Yasuhiro Miyazaki
• 👤 靖浩 宮崎
• 👤 Hiroo Okada
• 👤 岡田　浩郎
• 👤 Toshio Tsurukawa
• 👤 鶴川　敏雄
• 👤 Shiyouhei Kobayashi
• 👤 章兵 小林

Bibliographic Details