US3836261A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Device for detection of blemishes on opposite faces of a planar object
Assignee: Ferranti International PLC
•
Filing: 1973-07-18
•
Granted: 1974-09-17
•
Expires: 1993-07-18
Abstract
Abstract A detector of blemishes in opposite faces of a substantially planar object or web comprises a scanning station past which the object moves, the scanning station including a laser, a lens system to focus the beam onto the surface and a detector to receive light diffusely reflected from the surface and to produce a blemish signal when a change is detected in the amount of light reflected. The scanning station is arranged with respect to the object so that the beam scans in a direction normal to the plane of the object and mirrors are provided, inclined to each face of the object such that the scanning beam strikes each mirror in turn and is reflected therefrom to scan both faces of the object.
Inventors
- 👤 G Clarke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 07:03
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/84; G01N21/88; G01N21/89; G01N21/8901
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
177 words
A detector of blemishes in opposite faces of a substantially planar object or web comprising a scanning station arranged to be movable relative to the web in a parallel plane and containing a source of a beam of electromagnetic radiation, means for focussing the beam onto the object, scanning means for causing the beam to scan repetitively across the object, and means for receiving radiation diffusely reflected from the object and providing an output signal which alters in response to changes in intensity of the received radiation, the scanning station being arranged with respect to the object such that the beam from the scanning stAtion scans in a direction normal to the plane of the object, and a set of reflective surfaces in the path of the beam, said surfaces being arranged to lie adjacent to each of said opposite faces and inclined to the plane of the object such that in each scan the beam is reflected from each reflective surface in turn to scan said opposite faces transversely to the direction of said relative movement.
Claim 2
Dependent Claim
177 words
A detector of blemishes in opposite faces of a substantially planar object or web comprising a scanning station arranged to be movable relative to the web in a parallel plane and containing a source of a beam of electromagnetic radiation, means for focussing the beam onto the object, scanning means for causing the beam to scan repetitively across the object, and means for receiving radiation diffusely reflected from the object and providing an output signal which alters in response to changes in intensity of the received radiation, the scanning station being arranged with respect to the object such that the beam from the scanning stAtion scans in a direction normal to the plane of the object, and a set of reflective surfaces in the path of the beam, said surfaces being arranged to lie adjacent to each of said opposite faces and inclined to the plane of the object such that in each scan the beam is reflected from each reflective surface in turn to scan said opposite faces transversely to the direction of said relative movement.
Claim 3
Dependent Claim
55 words
A detector of blemishes as claimed in claim 1 in which the set of reflective surfaces comprises two such surfaces arranged one adjacent to each face of the object such that the planes of the mirrors intersect in a line in the plane of the object and extending in the direction of the relative movement.
Claim 4
Dependent Claim
82 words
A detector of blemishes as claimed in claim 1 in which the set of reflective surfaces comprises adjacent each face, a pair of mirrors equally inclined to the face and inclined to each other and spaced apart in the direction of said relative movement, the arrangement being such that the beam is reflected from one mirror of the pair onto the surface and radiation from the surface is reflected by the other mirror of the pair to said means for receiving radiation.
Claim 5
Dependent Claim
34 words
A detector of blemishes as claimed in claim 1 in which each set of reflective surfaces extends so as to lie adjacent a plurality of said planar objects located side-by-side in a single plane.
Claim 6
Dependent Claim
48 words
A detector of blemishes as claimed in claim 1 in which there is provided a plurality of sets of reflective surfaces arranged adjacent to each other in the direction of scan of the beam such that the beam is incident on each set of reflective surfaces in turn.
Claim 7
Dependent Claim
17 words
A detector of blemishes as claimed in claim 1 in which the reflective surfaces are plane mirrors.
Claim 8
Dependent Claim
22 words
A detector of blemishes as claimed in claim 1 in which the source of the beam of electromagnetic radiation is a laser.
References Cited (Backward Citations)
US3515475A
Cited
US3646353A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |