Optical storage medium inspection method for determining if an optical storage medium is good or defective

• US 7,583,578 B2
• Filed: 10/31/2007
• Issued: 09/01/2009
• Est. Priority Date: 04/03/2002
• Status: Expired due to Term

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Kadowaki, Shin-ichi, Nakamura, Atsushi, Ishida, Takashi, Shoji, Mamoru
• Primary Examiner(s): Agustin; Peter Vincent
• Application Number:
  US11/980,662
• Publication Number:
  US 20080247290A1
• Time in Patent Office: 671 Days
• Field of Search: None
• US Class Current: 369/53.34
• CPC Class Codes: G01N 21/9506 Optical discs
• CPC Class Codes: G01R 31/312 by capacitive methods
• CPC Class Codes: G01R 31/31709 Jitter measurements; Jitter generators measuring jitter, noise figure or signal-to-noise ratio per se G01R29/26; analysis of tester signals G01R31/31901
• CPC Class Codes: G11B 20/10009 Improvement or modification of read or write signals
• CPC Class Codes: G11B 20/10027 adjusting the signal strength during recording or reproduction, e.g. variable gain amplifiers optimum power control for optical discs G11B7/125
• CPC Class Codes: G11B 20/10055 using partial response filtering when writing the signal to the medium or reading it therefrom
• CPC Class Codes: G11B 20/10111 partial response PR(1,2,2,1)
• CPC Class Codes: G11B 20/10296 using the Viterbi algorithm
• CPC Class Codes: G11B 20/10481 optimisation methods
• CPC Class Codes: G11B 20/1217 on discs
• CPC Class Codes: G11B 20/1426 conversion to or from block codes or representations thereof
• CPC Class Codes: G11B 20/225 for reducing wow or flutter by controlling the speed of the record carrier G11B15/46, G11B19/28
• CPC Class Codes: G11B 2020/1239 the track being a pregroove, e.g. the wobbled track of a recordable optical disc
• CPC Class Codes: G11B 2020/1274 stored in pre-pits, i.e. in embossed pits, ROM marks or prepits
• CPC Class Codes: G11B 2020/1298 Enhancement of the signal quality
• CPC Class Codes: G11B 2220/2537 Optical discs
• CPC Class Codes: G11B 7/00375 arrangements for detection of physical defects, e.g. of recording layer
• CPC Class Codes: G11B 7/00456 Recording strategies, e.g. pulse sequences G11B7/0062 takes precedence
• CPC Class Codes: G11B 7/00458 Verification, i.e. checking data during or after recording

Abstract

An optical disc drive having an optical pickup head emitting a light beam to an optical storage medium, detecting the light beam reflected from the optical storage medium, and outputting a signal based on the received reflected light, having a jitter measuring unit measuring jitter in signals output from the optical pickup head and having an evaluation unit determining from the measured jitter if the optical storage medium is good or defective. The jitter measuring unit measures jitter in a train of 3T or longer marks or spaces from an optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k of two or more.

Claims

1. An optical storage medium inspection method for determining if an optical storage medium is good or defective, said method comprising:

emitting a light beam from an optical pickup head to the optical storage medium to which digital information is recorded as a train of marks or spaces of length kT based on a period T and an integer k;

receiving light reflected by a mark or space;

measuring jitter in signals based on the reflected light, but not measuring jitter in signals obtained from edges of shortest marks or spaces; and

determining from the measured jitter whether the optical storage medium is good or defective.