Patent US3751672A successfully refreshed from Google Patents.
US3751672A
Expired / Lapsed
US
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Opto-electronic apparatus for measuring and controlling the concentration of solutions
Assignee: Siemens AG
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Filing: 1972-04-28
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Granted: 1973-08-07
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Expires: 1992-04-28
Abstract
Abstract An improved opto-electronic apparatus for determining the concentration of solutions includes a probe having a prismatic immersion tip with at least two internally reflecting surfaces. A light-emitting means in the probe body directs a collimated beam of light through the prism toward a first reflecting surface of the probe tip, the incident beam making an angle with the first reflecting surface approximately equal to a critical angle of total reflection corresponding to the nominal index of refraction of the solution being examined. The included angle between subsequent reflecting surfaces is preferably approximately at least twice this critical angle. The light beam is reflected from a last reflecting surface toward an adjacent light receiving surface optically connected with a light-sensitive means in the probe body. Variations in the concentration of the solution in which the probe tip is immersed affect the intensity of the light beam finally reflected to the light-sensitive means, and the amplified output of the light-sensitive means provides a voltage suitable for use in measuring and controlling the concentration of the solution.
Inventors
- 👤 A Michel
- 👤 W Rummel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 18:58
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/41; G01N21/43; G01N21/431; Y; Y10; Y10S; Y10S250/00; Y10S250/90; Y10S250/901; Y10S250/902; Y10S250/903
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
208 words
Opto-electronic apparatus for determining the concentration of solutions in accordance with refractometric principles comprising: a probe having a body with a prism tip, the tip including at least two reflecting surfaces adapted to be immersed in the solution to be examined; light-emitting means; a light-transmitting surface positioned in the probe body adjacent a first one of the reflecting surfaces and optically connected with the light-emitting means for directing light rays from the emitting means through the prism at an acute angle to the first reflecting surface whereby at least a portion of the incident light is reflected successively toward the other reflecting surfaces when the probe tip is immersed in the solution to be examined, the angle between successive reflecting surfaces being approximately twice the critical angle of total reflection corresponding to the material of the probe tip and the average concentration of the solution to be examined; a light-receiving surface positioned in the probe body adjacent a last one of the reflecting surfaces, and a light-sensitive means optically connected to the lightreceiving surface and responsive to the intensity of the light rays reflected from the last reflecting surface for providing a signal having an amplitude that is a function of the concentration of the solution being examined.
Claim 2
Dependent Claim
208 words
Opto-electronic apparatus for determining the concentration of solutions in accordance with refractometric principles comprising: a probe having a body with a prism tip, the tip including at least two reflecting surfaces adapted to be immersed in the solution to be examined; light-emitting means; a light-transmitting surface positioned in the probe body adjacent a first one of the reflecting surfaces and optically connected with the light-emitting means for directing light rays from the emitting means through the prism at an acute angle to the first reflecting surface whereby at least a portion of the incident light is reflected successively toward the other reflecting surfaces when the probe tip is immersed in the solution to be examined, the angle between successive reflecting surfaces being approximately twice the critical angle of total reflection corresponding to the material of the probe tip and the average concentration of the solution to be examined; a light-receiving surface positioned in the probe body adjacent a last one of the reflecting surfaces, and a light-sensitive means optically connected to the lightreceiving surface and responsive to the intensity of the light rays reflected from the last reflecting surface for providing a signal having an amplitude that is a function of the concentration of the solution being examined.
Claim 3
Dependent Claim
25 words
The apparatus of claim 1 wherein the probe body is cylindrical and both the light-emitting means and the light-sensitive means are positioned within the body.
Claim 4
Dependent Claim
31 words
The apparatus of claim 1 wherein the light-emitting means is a light-emitting diode, and the light-transmitting surface is the end face of a light pipe optically connected to the light-emitting diode.
Claim 5
Dependent Claim
32 words
The apparatus of claim 1 further comprising a focusing lens positioned in the ray path between the light-emitting means anD the light-transmitting surface for collimating the light beam from the light-emitting means.
Claim 6
Dependent Claim
34 words
The apparatus of claim 1 wherein the light-receiving surface is one end face of a light pipe, and the light-sensitive means is a photodiode optically connected to the other end of the light pipe.
Claim 7
Dependent Claim
46 words
The apparatus of claim 1 wherein the tip of the probe comprises a flat-sided, multi-faced prism cut from a preformed bar of material transparent to the rays from the light-emitting means and mounted on the probe body in optical contact with the light-transmitting and light-receiving surfaces.
Claim 8
Dependent Claim
25 words
The apparatus of claim 1 wherein the probe body and prism tip are integrally formed from material transparent to the rays from the light-emitting means.
Claim 9
Dependent Claim
17 words
The apparatus of claim 7 wherein the probe body and tip are formed of methacrylic acid ester.
Claim 10
Dependent Claim
15 words
The apparatus of claim 7 wherein the probe body and tip are formed of polystyrene.
Claim 11
Dependent Claim
15 words
The apparatus of claim 7 wherein the probe body and tip are formed of polysulfone.
Claim 12
Dependent Claim
54 words
The apparatus of claim 1 wherein the number of reflecting surfaces in the probe tip is such that the direction of the light rays reflected from the last reflecting surface toward the light-receiving surface is approximately reversed from the direction of the light rays incident upon the first reflecting surface from the light-transmitting surface.
Claim 13
Dependent Claim
38 words
The apparatus of claim 11 wherein the probe tip includes at least four successive reflecting surfaces so that the total deflection of the light rays from the light-transmitting surface to the light-receiving surface is at least approximately 180*.
Claim 14
Dependent Claim
54 words
The apparatus of claim 1 wherein the number of reflecting surfaces in the probe tip is such that the direction of the light rays reflected from the last reflecting surface toward the light-receiving surface is approximately perpendicular to the direction of the light rays incident upon the first reflecting surface from the light-transmitting surface.
Claim 15
Dependent Claim
35 words
The apparatus of claim 13 wherein the probe tip includes only two successive reflecting surfaces so that the total deflection of the light rays from the light-transmitting surface to the light-receiving surface is approximately 90*.
Claim 16
Dependent Claim
34 words
The apparatus of claim 13 wherein the probe tip includes six successive reflecting surfaces so that the total deflection of the light rays from the light-transmitting surface to the light-receiving surface is approximately 270*.
Claim 17
Dependent Claim
38 words
The apparatus of claim 1 wherein the probe tip comprises a plurality of multi-faced prisms arranged in cascade such that the path of the light rays reflected from successive reflecting surfaces of the prisms describes an undulating waveform.
Claim 18
Dependent Claim
50 words
The apparatus of claim 5 further comprising a measuring amplifier electrically connected to the photodiode for amplifying its output signal and an adjustable shunt resistor connected between the photodiode and the amplifier for matching the operating range of the apparatus to the concentration range of the solution to be examined.
Claim 19
Dependent Claim
50 words
The apparatus of claim 5 further comprising an alternating power source connected to the light-emitting means for operating it in the pulsed mode and a frequency responsive amplifier tuned to the frequency of the power source and electrically connected to the output of the photodiode for amplifying its output signal.
Claim 20
Dependent Claim
32 words
The apparatus of claim 3 further comprising a temperature compensating element electrically connected in series with the light-emitting diode for compensating the temperature dependence of the light intensity from the light-emitting diode.
Claim 21
Dependent Claim
15 words
The apparatus of claim 19 wherein the temperature compensating element comprises at least one thermistor.
Claim 22
Dependent Claim
25 words
The apparatus of claim 1 wherein the light-emitting means is a light-emitting diode and the light-transmitting surface is the light-emitting face of said light-emitting diode.
Claim 23
Dependent Claim
25 words
The apparatus of claim 1 wherein the light-sensitive means is a photoelectric elemeNt and the light-receiving surface is the light-sensitive face of said photoelectric element.
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) | 1976-08-06 | 1977-02-05 | 1977-08-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-06 | 1981-02-05 | 1981-08-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-06 | 1985-02-05 | 1985-08-07 | $7700.00 | Window Closed / Lapsed |