OPTICAL HEAD - MATSUSHITA ELECTRIC IND CO LTD

Title:

OPTICAL HEAD

Document Type and Number:

WIPO Patent Application WO/1989/006424

Kind Code:

A1

Abstract:

An optical head with a center axis (18) includes a grating coupler (8) formed on a circular region having its center coincident with the center axis (18), and the grating coupler (8) has concentric circular grooves or a spiral grove having the same center (18). The grating coupler (8) couples a laser beam (7) from a semiconductor laser (5) to a light-guide layer (15B). This beam propagates, as a guided beam (16B), through a light-guide layer (15B). The beam (16B) becomes a guided beam (16A) when passing through an overlapping area of the layer (15B) with a light-guide layer (15A). The beam (16A) is radiated by a grating coupler (9), which includes concentric circular grooves or a spiral groove formed on an annular region having the same center (18). The radiated beam is focused at points (FA), (FB), and (FC) by the grating coupler (9) and then directed to the grating coupler (9) by a reflecting surface (19). The reflected beam incident to the coupler (9) is guided toward the center through the guide layer (15A) and radiated at the innermost edge of the layer (15A). The radiation is deteccted by a photosensor (10) which, in turn, produces control signals and reproduction signals.

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Inventors:

NISHIWAKI SEIJI (JP)
TAKETOMI YOSHINAO (JP)
UCHIDA SHINJI (JP)
TOMITA TAKAAKI (JP)
YONEZAWA TAKOTOSHI (JP)
MIZUNO SADAO (JP)

Application Number:

PCT/JP1988/001344

Publication Date:

July 13, 1989

Filing Date:

December 28, 1988

Export Citation:

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Assignee:

MATSUSHITA ELECTRIC IND CO LTD (JP)

International Classes:

G11B7/135; C09B23/00; C09B23/02; C09B23/10; C09B23/14; C09B29/00; C09B67/46; G03C1/825; G03C1/83; G03C5/16; G11B7/09; G11B7/12; G11B7/13; (IPC1-7): G11B7/135

Foreign References:

JPS60263350A

1985-12-26

Other References: