US3814946A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of detecting defects in transparent and semitransparent bodies
Assignee: AGC Inc
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Filing: 1972-12-04
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Granted: 1974-06-04
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Expires: 1992-12-04
Abstract
Abstract A method and apparatus for detecting defects in a transparent or semitransparent plate having a figured surface and an oppositely disposed smooth surface. A first light source is disposed on one side of the plate while a second light source is disposed on the opposite side so that the first light source and the second light source form, in conjunction with a photodetector, first and second optical systems respectively. The first optical system detects an internal defect in the plate by means of light which has passed through the plate and has been scattered by internal defects. The second optical system detects defects present in the smooth surface of the member by detecting light which has been reflected from the plate and scattered by surface defects.
Inventors
- 👤 S Takahashi
- 👤 T Asao
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 00:10
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/8901; G01N21/892; G01N21/896; G01N2021/8905; G01N2021/8907; G01N21/90
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
197 words
A method of detecting defects in a flat substantially transparent member having a figured surface on one side thereof and a smooth surface on an opposite side thereof comprising the steps of: directing a first collimated light beam onto said figured surface of said member in a spaced relationship to said figured surface so that said first collimated light beam passes through said member; directing a second collimated light beam onto said smooth surface of said member in a spaced relationship to said smooth surface so that said second collimated light beam reflects off said smooth surface of said member; positioning a photodetector means in a region of said smooth surface side of said member outside a region of said first and second collimated light beam passing through a non-defective portion and reflecting off a non-defective surface, respectively, of said member, and inside a region of said first and second collimated light beams passing through a defective portion and reflecting off a defective surface, respectively, of said member; and measuring a total amount of light received by said photodetector whereby both defects in said smooth surface of said member and internal defects in said member are detected.
Claim 2
Independent Claim
197 words
A method of detecting defects in a flat substantially transparent member having a figured surface on one side thereof and a smooth surface on an opposite side thereof comprising the steps of: directing a first collimated light beam onto said figured surface of said member in a spaced relationship to said figured surface so that said first collimated light beam passes through said member; directing a second collimated light beam onto said smooth surface of said member in a spaced relationship to said smooth surface so that said second collimated light beam reflects off said smooth surface of said member; positioning a photodetector means in a region of said smooth surface side of said member outside a region of said first and second collimated light beam passing through a non-defective portion and reflecting off a non-defective surface, respectively, of said member, and inside a region of said first and second collimated light beams passing through a defective portion and reflecting off a defective surface, respectively, of said member; and measuring a total amount of light received by said photodetector whereby both defects in said smooth surface of said member and internal defects in said member are detected.
Claim 3
Independent Claim
239 words
An apparatus for detecting defects in a flat substantially transparent member having a figured surface on one side thereof and a smooth surface on an opposite side thereof comprising: a first source of light disposed in a first side region of said member in a spaced relationship to the figured surface of said member, said first light source directing a first collimated beam onto said figured surface of said member and through said member; a second source of light disposed in an opposite side region of said member in a spaced relationship to said smooth surface of said member, said second light source directing a second collimated beam onto said smooth surface of said member, said second collimated beam reflecting from said smooth surface; and a photodetector means disposed on said opposite side of said member in a spaced relationship thereto at a position outside a region of light from said first source having passed through a non-defective portion of said member and light from said second source having been reflected from said smooth surface of said member having no defects, and inside a region where light from said first source having passed through a defective portion of said member and light from said second source having been reflected from surface defects in said smooth surface of said member are significant; whereby light received by said photodetector means is indicative of internal and smooth surface defects of said member.
Claim 4
Independent Claim
239 words
An apparatus for detecting defects in a flat substantially transparent member having a figured surface on one side thereof and a smooth surface on an opposite side thereof comprising: a first source of light disposed in a first side region of said member in a spaced relationship to the figured surface of said member, said first light source directing a first collimated beam onto said figured surface of said member and through said member; a second source of light disposed in an opposite side region of said member in a spaced relationship to said smooth surface of said member, said second light source directing a second collimated beam onto said smooth surface of said member, said second collimated beam reflecting from said smooth surface; and a photodetector means disposed on said opposite side of said member in a spaced relationship thereto at a position outside a region of light from said first source having passed through a non-defective portion of said member and light from said second source having been reflected from said smooth surface of said member having no defects, and inside a region where light from said first source having passed through a defective portion of said member and light from said second source having been reflected from surface defects in said smooth surface of said member are significant; whereby light received by said photodetector means is indicative of internal and smooth surface defects of said member.
References Cited (Backward Citations)
US3030516A
Cited
US3085160A
Cited
US3338130A
Cited
US3361025A
Cited
US3415433A
Cited
US3386579A
Cited
US3302786A
Cited
US3478218A
Cited
US3493769A
Cited
US3475615A
Cited
US3533704A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-03 | 1977-12-03 | 1978-06-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-03 | 1981-12-03 | 1982-06-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-03 | 1985-12-03 | 1986-06-04 | $7700.00 | Window Closed / Lapsed |