Patent US3790290A successfully refreshed from Google Patents.
US3790290A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Single modulated light beam photometer
Assignee: Erwin Sick GmbH Optik Elektronik
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Filing: 1972-08-03
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Granted: 1974-02-05
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Expires: 1992-08-03
Abstract
Abstract A photometer in which a light beam is split by a mirror into measurement and reference portions, the reference portion of the beam being reflected back through the beam splitting mirror to a photoelectric device. The measurement portion of the beam is reflected back to the beam splitting mirror from which it is reflected to the photoelectric device. The photoelectric device compares intensities of the two received beam portions and provides indication representative of transmission, extinction and remission.
Inventors
- 👤 J Muller
- 👤 A Triller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 09:45
CPC Classifications
G; G01; G01J; G01J1/00; G01J1/10; G01J1/16; G01J1/1626; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/49; G01N21/53; G01N21/534
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
126 words
A photometer, in the case of which a light pencil, emitted by a light source, is split up by a beam splitting mirror into a measurement and a reference pencil, which after passing along the measurement and reference paths respectively and reflection at a respective mirror and again passing through and reflection at, respectively, the ray splitting mirror are supplied to a photoelectric device with an associated electronic circuit, which by comparison of the intensities of the measuring and reference pencils provides an indication which is representative for the transmission, extinction or remission, characterized in that the photoelectric device consists of two adjacent photo-electric cells, to which the measurement and reference light pencils, respectively, pass by a slight tipping of the mirror reflecting the reference pencil.
Claim 2
Dependent Claim
126 words
A photometer, in the case of which a light pencil, emitted by a light source, is split up by a beam splitting mirror into a measurement and a reference pencil, which after passing along the measurement and reference paths respectively and reflection at a respective mirror and again passing through and reflection at, respectively, the ray splitting mirror are supplied to a photoelectric device with an associated electronic circuit, which by comparison of the intensities of the measuring and reference pencils provides an indication which is representative for the transmission, extinction or remission, characterized in that the photoelectric device consists of two adjacent photo-electric cells, to which the measurement and reference light pencils, respectively, pass by a slight tipping of the mirror reflecting the reference pencil.
Claim 3
Dependent Claim
32 words
A photometer in accordance with claim 1, characterized in that a modulation is carried out by a chopper with a single frequency before splitting up into the measurement and reference light pencils.
Claim 4
Dependent Claim
32 words
A photometer in accordance with claim 2, characterized in that the light source is focussed or projected by a condensor onto the holes of a chopper wheel which accomplishes the frequency modulations.
Claim 5
Dependent Claim
18 words
A photometer in accordance with claim 3, characterized in that the frequency of modulation amounts to 4 kHz.
Claim 6
Dependent Claim
51 words
A photometer in accordance with claim 3, characterized in that a microobjective, arranged behind the chopper wheel, projects the image of the filament of the source of light into the objective located at the beginning of the measurement path, and the splitting mirror is arranged between the microobjective and the objective.
Claim 7
Dependent Claim
28 words
A photometer in accordance with claim 5 characterized in that the measuring path is located in an extension of the optical axis of the light source ray path.
Claim 8
Dependent Claim
32 words
A photometer in accordance with claim 6, characterized in that the reflecting mirror which reflects the reference pencil and the photoelectric cells are arranged transversely with respect to the principal ray path.
Claim 9
Dependent Claim
33 words
A photometer in accordance with claim 7 characterized in that the reflecting mirror is spherical or parabolic so that it concentrates the instant light of the reference beam onto the second photoelectric cell.
Claim 10
Dependent Claim
21 words
A photometer in accordance with claim 1 characterized in that the two adjacent photo-electric cells are accommodated in a common housing.
Claim 11
Dependent Claim
119 words
A photometer in accordance with claim 1 characterized in that the electronic circuit includes means connecting the output measurement signal from one of said photo-electric cells to the input side of a high pass filter and the output side of said high pass filter to the input side of a variable gain amplifier and further includes means connecting the output reference signal from the other of said photo-electric cells to the input side of a high pass filter and means connecting the output side of said last named high pass filter with the input side of a rectifier and low pass filter and means connecting the output froM the latter with the input side of said variable gain amplifier.
Claim 12
Dependent Claim
106 words
A photometer in accordance with claim 1 using unmodulated light, characterized in that the electronic circuit includes means connecting the output measurement signal from one of said photo-electric cells to the input side of a low pass filter and the output side of said low pass filter to the input side of a variable gain amplifier and further includes means connecting the output reference signal from the other of said photo-electric cells to the input side of a low pass filter and means connecting the output side of said last named low pass filter with the input side of said variable gain amplifier via a chopper.
Claim 13
Dependent Claim
34 words
A photometer in accordance with claim 1 characterized in that the measurement photoelectric cell is connected via a chopper and the reference photo-electric cell via a low pass filter with a variable gain amplifier.
Claim 14
Dependent Claim
33 words
A photometer in accordance with claim 1 characterized in that in front of each photoelectric cell a converging lens is arranged which combines the light concentrated on them in the associated photo-electric cells.
Claim 15
Dependent Claim
26 words
A photometer in accordance with claim 1 characterized in that directly in front of the photo-electric cells a correction filter is arranged to eliminate undesired frequencies.
References Cited (Backward Citations)
US3488122A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-02-04 | 1977-08-06 | 1978-02-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-04 | 1981-08-06 | 1982-02-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-04 | 1985-08-06 | 1986-02-05 | $7700.00 | Window Closed / Lapsed |