US RE40,017 E1
Optical recording/reproducing apparatus for optical disks with various disk substrate thicknesses
Naoyasu Miyagawa, Suita (Japan); and Yasuhiro Gotoh, Kadoma (Japan)
Assigned to Matsushita Electric Industrial Co., Ltd., Osaka (Japan)
Filed on Oct. 23, 2003, as Appl. No. 10/693,810.
Application 07/740629 is a continuation of application No. 09/460223, filed on Dec. 13, 1999.
Application 09/460223 is a continuation of application No. 08/396981, filed on Mar. 01, 1995, granted, now Re. 36445, filed on Dec. 14, 1999.
Application 10/693810 is a reissue of application No. 07/740629, filed on Aug. 05, 1991, now 5,235,581, filed on Aug. 10, 1993.
Claims priority of application No. 02-212537 (JP), filed on Aug. 09, 1990; application No. 02-285006 (JP), filed on Oct. 22, 1990; and application No. 03-044798 (JP), filed on Mar. 11, 1991.
Int. Cl. G11B 7/11 (2006.01)
U.S. Cl. 369—53.22  [369/94; 369/44.37; 369/44.12; 369/44.23; 369/112.24; 369/53.2] 4 Claims
OG exemplary drawing
 
[ 25. A signal processing circuit used for an optical disc apparatus which includes a light source driving circuit for controlling a plurality of light sources and which records, reproduces or erases an information signal onto/from any one of N types (where N>2) of optical discs having transparent substrates of different thicknesses, each of said types of optical discs having at least a said transparent substrate and an information layer, by converging a light beam emitted from one of the light sources according to a control signal from the light source driving circuit onto the information layer through the transparent substrate, each of said light sources corresponding to a respective one of said disc types, and by detecting a reflected light beam with an optical detector, the signal processing circuit comprising:
a discriminating signal generator, connected with the optical detector, for generating a disc discrimination signal indicating the one of said types of optical discs; and
a controller for controlling the light source driving circuit to selectively activate one of the light sources according to the disc discrimination signal.]