US3718399A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Distance compensated reflectance sensor
Assignee: Individual
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Filing: 1971-06-29
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Granted: 1973-02-27
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Expires: 1991-06-29
Abstract
Abstract A distance compensated reflectance sensor is presented having a hand held sensing unit for sensing reflectance from surfaces to be measured and generating a signal thereof to be delivered to a main unit where the signal is compared with preset standards or limits for generation of a warning signal if the measured reflectance departs from desired values. The hand held sensor element has a light source, a detector element, and a baffle structure. The baffle provides a partial overlap of the illuminated field and the viewing field, to provide for automatic compensation in the event of the deviation in distance between the surface being examined and the detector element. The source, the detector, and the baffle are arranged so that all direct and directly reflected light are blocked from the detector, i.e., the detector sees only scattered light.
Inventors
- 👤 G Kalman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 04:37
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4738; G01N21/474; G01N2201/00; G01N2201/06; G01N2201/064; G01N2201/0642
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
205 words
A distance compensated reflectance sensor element including an enclosure defining an opening adapted to be held against a surface to be investigated and to estAblish a surface position which may vary relative to said enclosure; illuminating means in said sensor element spaced from said opening for illuminating the surface to be investigated and establishing a field of illumination; detector means in said sensor element spaced from said opening for viewing the surface to be investigated and establishing a field of viewing, said illuminating field and said viewing field being at least partly overlapping said detector means being adapted for generating a signal commensurate with light incident thereon, said fields overlapping on said surface when it is in said surface position, means restricting said fields so that no rays from the illuminating means impinge directly upon the detector means and so that no rays reflected by the surface impinge upon the detector means, the area of said overlapping on said surface being of predetermined value when said surface position is a predetermined distance from said detector means, and means for varying said area of overlapping directly with the variation of said distance whereby the light impinging upon the detector means is substantially independent of said distance.
Claim 2
Dependent Claim
205 words
A distance compensated reflectance sensor element including an enclosure defining an opening adapted to be held against a surface to be investigated and to estAblish a surface position which may vary relative to said enclosure; illuminating means in said sensor element spaced from said opening for illuminating the surface to be investigated and establishing a field of illumination; detector means in said sensor element spaced from said opening for viewing the surface to be investigated and establishing a field of viewing, said illuminating field and said viewing field being at least partly overlapping said detector means being adapted for generating a signal commensurate with light incident thereon, said fields overlapping on said surface when it is in said surface position, means restricting said fields so that no rays from the illuminating means impinge directly upon the detector means and so that no rays reflected by the surface impinge upon the detector means, the area of said overlapping on said surface being of predetermined value when said surface position is a predetermined distance from said detector means, and means for varying said area of overlapping directly with the variation of said distance whereby the light impinging upon the detector means is substantially independent of said distance.
Claim 3
Dependent Claim
39 words
The invention as defined in claim 1 wherein said fields are divergent and wherein said means for varying said area is a barrier with a bounding edge extending into the fields of the illumination means and the detector means.
Claim 4
Dependent Claim
23 words
The invention as defined in claim 2 including indicating means connected with said detector means for indicating the relative value of said signal.
Claim 5
Dependent Claim
43 words
The invention as defined in claim 2 including comparator means for receiving said signal from said detector means and comparing said signal with a desired standard; and indicator means connected with said comparator means for indicating adherence to or deviation from said standard.
Claim 6
Dependent Claim
77 words
The invention as defined in claim 4 wherein said comparator means includes differential comparator means for establishing upper and lower limits for the surface to be investigated and for comparing said signal from said detector with said limits; and wherein said differential comparator means drives said indicator means to a first state when said signal is above said upper limit or below said lower limit and to a second state when said signal is between said limits.
Claim 7
Dependent Claim
20 words
The invention as defined in claim 5 wherein said differential comparator is adjustable to define variable upper and lower limits.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-02-27 | 1976-08-28 | 1977-02-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-02-27 | 1980-08-28 | 1981-02-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-02-27 | 1984-08-28 | 1985-02-27 | $7700.00 | Window Closed / Lapsed |