EP0182647A2
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EP
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Reflectometer
Assignee: Trividia Health Inc
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Filing: 1985-11-18
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Granted: —
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Expires: 2005-11-18
Abstract
Abstract A reflectometer has an optical chamber comprising a light source (Q1) for illuminating a test specimen (9) and a relfec- tance photosensor (Q3) responsive to light reflected from the test specimen to produce a reflectance signal corresponding to the reflectance of the specimen. The reflectance photosensor (Q3) is disposed along an optical path (5) having its optical axis (12) inclined to the optical axis (11) of the optical path (4) along which light is projected onto the test specimen by the light source (Q1) so that the photosensor (Q3) detects random reflections from the test specimen (9). The optical chamber may also include a reference photosensor (Q2), a beam splitter (15) arranged to reflect a minor fraction of the light emitted by the light source (Q1) onto the reference photosensor, and a drive circuit for the light source which is responsive to a control signal derived from the reference sensor (Q2) and which provides for pulsed operation of the light source so as to maintain the control signal generally at a constant level.
Inventors
- 👤 Robert Joseph Salem
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 07:54
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/17; G01N21/47; G01N21/4738; G01N21/474; G01J; G01J1/00; G01J1/10; G01J1/16; G01J1/1626; G01J2001/1636; G01N2021/4752; G01N2021/4757; G01N2021/4776; G01N2021/478; G01N2201/00; G01N2201/06; G01N2201/062; G01N2201/0621; G01N2201/12; G01N2201/126
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
98 words
An optical chamber for a reflectometer, comprising at least one light source (Q1) arranged to illuminate a test specimen (9) via a first optical path (4,41) and at least one reflectance photosensor (Q3) for detecting light reflected from said test specimen, characterised in that the reflectance photosensor (Q3) is disposed along a second optical path (5,42) having its optical axis (12,45) inclined to the optical axis (11,46) of the first optical path (4,41) and intersecting said first optical axis (11,46) at or adjacent the test specimen (9), whereby the photosensor (Q3) detects random reflections from the test specimen.
Claim 2
Dependent Claim
98 words
An optical chamber for a reflectometer, comprising at least one light source (Q1) arranged to illuminate a test specimen (9) via a first optical path (4,41) and at least one reflectance photosensor (Q3) for detecting light reflected from said test specimen, characterised in that the reflectance photosensor (Q3) is disposed along a second optical path (5,42) having its optical axis (12,45) inclined to the optical axis (11,46) of the first optical path (4,41) and intersecting said first optical axis (11,46) at or adjacent the test specimen (9), whereby the photosensor (Q3) detects random reflections from the test specimen.
Claim 3
Dependent Claim
46 words
An optical chamber according to claim 1, characterised in that the optical axis (12,45) of the second optical path is inclined to the optical axis (11,46) of the first optical path at an angle of at least 20° and, preferably at an angle of approximately 35°.
Claim 4
Dependent Claim
85 words
An optical chamber according to claim 1 or 2, characterised in that the test specimen (9) is in the form of a test strip, and means is provided for locating said test strip along the first optical path (4) with the plane of said strip disposed substantially perpendicular to the first optical axis (11), and further characterised in that a protective lens device (13) is disposed across the first and second optical paths (4,5) adjacent the position at which the test strip (9) is located.
Claim 5
Dependent Claim
97 words
An optical chamber according to claim 1, 2 or 3, characterised by at least one reference photosensor (Q2) disposed along a third optical path (6,48), for example, having its optical axis (14) substantially perpendicular to the optical axis (11) of the first optical path (4), and beam splitter means (15,51) arranged to reflect a minor fraction of the light emitted by said at least one light source (Q1), along the third optical path (6,48) and onto the reference sensor (Q2) whilst transmitting a major fraction of the light so as to impinge on the test specimen (9).
Claim 6
Dependent Claim
49 words
An optical chamber according to claim 4, characterised by a drive circuit for the or each light source (Q1) which is responsive to a control signal derived from the associated reference sensor (Q2) and which operates the light source to maintain the control signal at a generally constant level.
Claim 7
Dependent Claim
29 words
An optical chamber according to claim 4 or 5, characterised in that the or each light source (Q1) is a light emitting diode and the sensors (Q2,Q3) are photodiodes.
Claim 8
Dependent Claim
114 words
A reflectometer including an optical chamber having at least one light source (Q1) for illuminating a test specimen (9), and at least one reflectance photosensor (Q3) responsive to light reflected from the test specimen to produce a reflectance signal corresponding to the reflectance of the specimen, characterised by at least one reference photosensor (Q2) responsive to a fraction of the light emitted by said at least one light source (Q1), and a drive circuit (24) for the or each light source which is responsive to a control signal derived from the associated reference sensor (Q2) and which operates the light source (Q1) so as to maintain said control signal generally at a constant level.
Claim 9
Dependent Claim
114 words
A reflectometer including an optical chamber having at least one light source (Q1) for illuminating a test specimen (9), and at least one reflectance photosensor (Q3) responsive to light reflected from the test specimen to produce a reflectance signal corresponding to the reflectance of the specimen, characterised by at least one reference photosensor (Q2) responsive to a fraction of the light emitted by said at least one light source (Q1), and a drive circuit (24) for the or each light source which is responsive to a control signal derived from the associated reference sensor (Q2) and which operates the light source (Q1) so as to maintain said control signal generally at a constant level.
Claim 10
Dependent Claim
76 words
A reflectometer according to claim 7, characterised in that the drive circuit comprises comparator means (U3B) which compares the control signal derived from the reference sensor (Q2) with a reference signal, and a switching device (Q6) for controlling the light source (Ql) and whicn is responsive to the comparator means, whereby to actuate the light source so as to maintain the control signal generally at a constant level, for example, the level of the reference signal.
Claim 11
Dependent Claim
61 words
A reflectometer according to claim 7 or 8, characterised by a reference sensor amplifier (U2) for the reference photosensor (Q2), a first integrating circuit (R12,C14) for integrating the output of said reference sensor amplifier, and a first voltage divider (R13-R16) connected to the output of said amplifier, said control signal for the drive circuit being derived from said first voltage divider.
Claim 12
Dependent Claim
25 words
A reflectometer according to claim 7, 8 or 9, characterised by means (25) for producing a digital reflectance signal corresponding to the reflectance sensor output.
Claim 13
Dependent Claim
51 words
A reflectometer according to claim 10, characterised by a reflectance sensor amplifier (U1) for the reflectance sensor (Q3), a second integrating circuit (R7,C13) for integrating the output of said reflectance sensor amplifier, and means (25) for processing the output signal of said reflectance sensor amplifier to produce a digital reflectance signal.
Claim 14
Dependent Claim
55 words
A reflectometer according to claim 10 or 11, characterised in that the means for producing a digital reflectance signal includes an analog-to-digital converter (25) which compares an analog reflectance signal derived from the reflectance sensor output with a reference signal and produces a pulse train having a pulse rate corresponding to the analog reflectance signal.
Claim 15
Dependent Claim
90 words
A reflectometer according to claim 12, characterised by a fixed gain amplifier (U3D) having inputs connected to the output of the reflectance sensor amplifier (U1) and the first voltage divider (R13-R16), respectively, said analog-to-digital converter (25) being connected to the output of the fixed gain amplifier, and the connection of the drive circuit to the first voltage divider being adjustable so as to determine the light standard reflectance and the connection of the fixed gain amplifier (U3D) to the first voltage divider being adjustable to determine the dark standard reference.
Claim 16
Dependent Claim
54 words
A reflectometer according to claim 12 or 13, characterised by a second voltage divider (R9,R10) for producing the reference signal, and a reference amplifier (U3A), said second voltage divider being connected to the drive circuit and the reference amplifier, and the output of said reference amplifier (U3A) being connected to the analog-to-digital converter (25).
Claim 17
Dependent Claim
49 words
A reflectometer according to claim 14, wherein the analog-to-digital converter (25) compares the analog reflectance signal and the reference signal derived from the reference amplifier (U3A) and produces a digital reflectance signal in the form of a pulse train having a pulse rate corresponding to the analog reflectance signal.
Claim 18
Dependent Claim
28 words
A reflectometer according to any preceding claim 10 to 15, characterised by central processing means (U6) for processing the digital reflectance signal and producing a measurement of reflectance.
References Cited (Backward Citations)
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