The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 12, 1995
Filed:
Jul. 14, 1994
Naoaki Tani, Hachioji, JP;
Mitsuo Oshiba, Hachioji, JP;
Olympus Optical Co., Ltd., Tokyo, JP;
Abstract
An apparatus for writing and reading information on and from an optical card by projecting a writing light beam and at least two reading light beams onto the optical card includes a first semiconductor laser for emitting a writing laser beam, a second semiconductor laser for emitting a reading laser beam, a diffraction grating for diffracting the reading laser beam into multiple reading laser beams, and an objective lens for projecting the writing laser beam and the reading laser beams onto the optical card. A reading laser beam spot is formed on the optical card at a middle point between two reading laser beam spots. Images of the reading laser beam spots are received by first and second light receiving elements, respectively. By processing output signals from the first and second light receiving elements, it is possible to verify the recorded condition of pits immediately after recording in regardless of a direction in which the optical card is moved. It is also possible to check the condition of the information track immediately before the writing. In this manner, the writing operation can be performed at a high speed in a suitable and reliable manner.