EP0152165A2
Expired / Lapsed
EP
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Defect inspecting apparatus for inspecting defects in optical type disc
Assignee: Victor Company of Japan Ltd
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Filing: 1985-01-07
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Granted: —
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Expires: 2005-01-07
Abstract
Abstract A defect inspecting apparatus for inspecting defects in an optical type disc comprises a motor (11) for rotating an optical type disc (10) which is to be inspected, a light beam generator (13) for generating a light beam, a lens system (14, 15) for irradiating the light beam generated from the light beam generator on a signal recording range (28) of the disc over a predetermined range, an image sensor (18) for subjecting a light beam reflected from a signal recording surface (21) of the disc to-a photoelectric conversion, and a detecting circuit (41-47) for detecting a change in an output signal level of the image sensor so as to detect the existence of defects in the disc. The lens system converts the light beam generated from the light beam generator into a light beam having a cross section of a predetermined shape so that an irradiated part (30) on the disc extends in a radial direction of the disc, and the length of the irradiated part in the radial direction of the disc is at least slightly greater than the width of the signal recording range in the radial direction of the disc.
Inventors
- 👤 Goro Fujiki
- 👤 Isao Owaki
- 👤 Kouji Nemoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 04:21
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/95; G01N21/9506; G11; G11B; G11B7/00; G11B7/002; G11B7/0037; G11B7/00375; G11B7/12; G11B7/13
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
208 words
A defect inspecting apparatus for inspecting defects in an optical type disc, said defect inspecting apparatus comprising a motor (11) for rotating an optical type disc (10) which is to be inspected, light beam generating means (13) for generating a light beam, a lens system (14, 15) for irradiating the light beam generated from said light beam generating means on a signal recording range (28) of said disc over a predetermined range, image sensor means (18) for subjecting a light beam reflected from a signal recording surface (21) of said disc to a photoelectric conversion, and detecting means (41-47) for detecting a change in an output signal level of said image sensor means so as to detect the existence of defects in said disc, characterized in that said lens system (14, 15) converts the light beam generated' from said light beam generating means (13) into a light beam having a cross section of a predetermined shape so that an irradiated part (30) on said disc (10) extends in a radial direction of said disc, the length of said irradiated part in the radial direction of said disc being at least slightly greater than the width of said signal recording range (28) in the radial direction of said disc.
Claim 2
Dependent Claim
208 words
A defect inspecting apparatus for inspecting defects in an optical type disc, said defect inspecting apparatus comprising a motor (11) for rotating an optical type disc (10) which is to be inspected, light beam generating means (13) for generating a light beam, a lens system (14, 15) for irradiating the light beam generated from said light beam generating means on a signal recording range (28) of said disc over a predetermined range, image sensor means (18) for subjecting a light beam reflected from a signal recording surface (21) of said disc to a photoelectric conversion, and detecting means (41-47) for detecting a change in an output signal level of said image sensor means so as to detect the existence of defects in said disc, characterized in that said lens system (14, 15) converts the light beam generated' from said light beam generating means (13) into a light beam having a cross section of a predetermined shape so that an irradiated part (30) on said disc (10) extends in a radial direction of said disc, the length of said irradiated part in the radial direction of said disc being at least slightly greater than the width of said signal recording range (28) in the radial direction of said disc.
Claim 3
Dependent Claim
90 words
A defect inspecting apparatus as claimed in claim 1, characterized in that said lens system (14, 15) converts the light beam generated from said light beam generating means (13) into a light beam having an approximately rectangular cross section so that said irradiated part (30) on said disc (10) has an approximately rectangular shape having a longer side extending in the radial direction of said disc, said longer side being at least slightly greater than the width of said signal recording range (28) in the radial direction of said disc.
Claim 4
Dependent Claim
65 words
A defect inspecting apparatus as claimed in claim 2, characterized in that said lens system (14, 15) comprises a collimator lens (14) for converting the light beams generated from said light beam generating means (13) into a cylindrical light beam, and a cylindrical lens (15) for converting the cylindrical light beam from said collimator lens into said light beam having the approximately rectangular cross section.
Claim 5
Dependent Claim
30 words
A defect inspecting apparatus as claimed in claim 1, characterized in that said image sensor means (18) comprises a line sensor having a plurality of linearly arranged photoelectric converting elements.
Claim 6
Dependent Claim
180 words
A defect inspecting apparatus as claimed in claim 1, characterized in that said detecting means (41-47) produces a signal which assumes a low level in correspondence with a level changing part of the output of said image sensor means (18), and said defect inspecting apparatus further comprises a clock pulse generator (52) for generating clock pulses, a radial address counter (50) for counting the output clock pulses of said clock pulse generator, first and second latch circuits (48, 49) for latching an output counted value of said address counter responsive to the output signal of said detecting means, said first latch circuit latching the output counted value of said address counter responsive to a falling edge of the output signal of said detecting means so as to produce a radial address representing a position where a detected defect starts, said second latch circuit latching the output counted value of said address counter responsive to a rising edge of the output signal of said detecting means so as to produce a radial address representing a position where the detected defect ends.
Claim 7
Dependent Claim
69 words
A defect inspecting apparatus as claimed in claim 5, characterized in that said image sensor means (18) comprises a line sensor having a plurality of linearly arranged photoelectric converting elements, and said output clock pulses of said clock pulse generator (52) are supplied to said image sensor means so that said image sensor means successively produces outputs of each of said photoelectric sensor elements responsive to said clock pulses.
Claim 8
Dependent Claim
58 words
A defect inspecting apparatus as claimed in claim 5, characterized in that said defect inspecting apparatus further comprises a discriminating circuit (51) supplied with the output radial addresses of said first and second latch circuits (48, 49) for discriminating from the radial addresses supplied thereto the length of the detected defect in the radial direction of said disc.
Claim 9
Dependent Claim
58 words
A defect inspecting apparatus as claimed in claim 7, characterized in that said discriminating circuit (51) discriminates the length of the detected defect in a circumferential direction of said disc from a plurality of radial addresses produced from said first and second latch circuits (48, 49) during a plurality of scans in the radial direction of said disc.
Claim 10
Dependent Claim
53 words
A defect inspecting apparatus as claimed in claim 5, characterized in that said discriminating circuit (51) discriminates the shape, size, and number of detected defects from a plurality of radial addresses produced from said first and second latch circuits (48, 49) during a plurality of scans in the radial direction of said disc.
References Cited (Backward Citations)
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