EP0308537A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Sensor for converting a distance to optical and further to electrical energy, and surface scanning apparatus using same
Assignee: Leica Microsystems Holdings GmbH
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Filing: 1987-09-25
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Granted: —
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Expires: 2007-09-25
Abstract
Abstract A sensor body (1) is formed as a light waveguide for laser light (2). A light exit site (10) for light diffracted within the sensor body (1) is located at a surface (6) thereof which faces away from a measured body (M). A detection particle (15) is located at the surface (5) of the sensor body (1) facing the measured body (M). It has a substantially convex and rounded off form and a major dimension which is smaller than the wavelength of the light (2). The measured body (M) is located in the optical near field of the detection particle (15). The latter has a major dimension of 5 to 500 nm and preferably of 20 to 100 nm. A detector means (11) converts the optical energy of the diffracted light to an electrical detector signal. A continuous thin film (16) is provided as a coating for the sensor (S). It substantially covers the detection particle (15) and at least part of the surface (5) of the sensor body (1) in the vicinity of the detection particle (15) It has a thickness which is smaller than one half of said predetermined wavelength. Preferably it is formed of gold and has a thickness of less than 100 nm. The sensor is used to finally convert a distance to an electrical quantity.
Inventors
- 👤 Urs Theodor Dr. Dürig
- 👤 Ulrich Christian Dr. Fischer
- 👤 Wolfgang Dieter Dr. Pohl
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-07 14:45
CPC Classifications
G; G01; G01B; G01B11/00; G01B11/30; G01B11/306; G01Q; G01Q20/00; G01Q20/02; G01Q60/00; G01Q60/18; G01Q60/22; G11; G11B; G11B11/00; G11B11/10; G11B11/105; G11B11/10532; G11B21/00; G11B21/16; G11B21/20; G11B5/00; G11B5/48; G11B5/58; G11B5/60; G11B5/6005; G11B9/00; G11B9/12; G11B9/14; G11B9/1409
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
314 words
Optical sensor for converting a distance to a quantity of optical energy while using laser light of a predetermined wavelength and for converting said quantity of optical energy to an electrical quantity, said distance being defined between a reference site (14) at the sensor (S) and a measurement site (18) at a surface (17) of a measured body (M) located opposite the sensor (S) and being small enough for the measurement site (18) to be located, at the predetermined wavelengths, in the optical near field of the reference site (14), comprising a sensor body (1) formed as a light waveguide for said laser light (2) and having a light entrance site (3) and a first light exit site (4) for light guided through the sensor body (1) and a second light exit site (10) for light diffracted within the sensor body (1), said second light exit site (10) being located at a surface (6) of the sensor body (1) on a side thereof which faces away from the measured body (M), a detection particle (15) acting as an antenna, located at the surface (5) of the sensor body (1) between said light entrance site (3) and said first light exit site (4) and having a substantially convex and rounded off form and a major dimension which is smaller than said predetermined wavelength, and a detector means (11) for converting the optical energy of that light which leaves the sensor body (1) at the second light exit site (10) to an electrical detector signal, characterized by a continuous thin film (16) provided as a coating for the sensor (S) in such manner as to substantially cover the detection particle (15) and at least part of the surface (5) of the sensor body (1) in the vicinity of the detection particle (15), said thin film (16) having a thickness which is smaller than said predetermined wavelength.
Claim 2
Dependent Claim
314 words
Optical sensor for converting a distance to a quantity of optical energy while using laser light of a predetermined wavelength and for converting said quantity of optical energy to an electrical quantity, said distance being defined between a reference site (14) at the sensor (S) and a measurement site (18) at a surface (17) of a measured body (M) located opposite the sensor (S) and being small enough for the measurement site (18) to be located, at the predetermined wavelengths, in the optical near field of the reference site (14), comprising a sensor body (1) formed as a light waveguide for said laser light (2) and having a light entrance site (3) and a first light exit site (4) for light guided through the sensor body (1) and a second light exit site (10) for light diffracted within the sensor body (1), said second light exit site (10) being located at a surface (6) of the sensor body (1) on a side thereof which faces away from the measured body (M), a detection particle (15) acting as an antenna, located at the surface (5) of the sensor body (1) between said light entrance site (3) and said first light exit site (4) and having a substantially convex and rounded off form and a major dimension which is smaller than said predetermined wavelength, and a detector means (11) for converting the optical energy of that light which leaves the sensor body (1) at the second light exit site (10) to an electrical detector signal, characterized by a continuous thin film (16) provided as a coating for the sensor (S) in such manner as to substantially cover the detection particle (15) and at least part of the surface (5) of the sensor body (1) in the vicinity of the detection particle (15), said thin film (16) having a thickness which is smaller than said predetermined wavelength.
Claim 3
Dependent Claim
25 words
Sensor according to claim 1, characterized in that the detector means (11) is formed as an integral part of the sensor body (1). (Fig. 2)
Claim 4
Dependent Claim
29 words
Sensor according to claim 1, characterized in that the detector means (11) is arranged at the sensor body (1) adjacent to the second light exit site (10). (Fig. 1)
Claim 5
Dependent Claim
30 words
Sensor according to claim 1, characterized in that the detector means (11) is linked to the second light exit site (10) by means of a light waveguide (13). (Fig. 3)
Claim 6
Dependent Claim
28 words
Sensor according to claim 1, characterized in that the detection particle (15) has a major dimension of less than 500 nm and preferably of 20 to 100 nm.
Claim 7
Dependent Claim
31 words
Sensor according to claim 1, characterized in that the detection particle (15) is formed of a metal in which, at the predetermined wavelength, the excitation of plasmons or polaritons is possible.
Claim 8
Dependent Claim
18 words
Sensor according to claim 1, characterized in that the detection particle (15) is formed of a dielectric material.
Claim 9
Dependent Claim
16 words
Sensor according to claim 1, characterized in that the detection particle (15) is a latex spherule.
Claim 10
Dependent Claim
31 words
Sensor according to claim 1, characterized in that the thin film (16) is formed of a metal in which, at the predetermined wavelength, the excitation of plasmons or polaritons is possible.
Claim 11
Dependent Claim
33 words
Sensor according to one of the claims 6 and 9, charactrized in that the predetermined wavelength is selected within the visible light spectrum and the metal is selected from gold, silver and copper.
Claim 12
Dependent Claim
25 words
Sensor according to claim 9, characterized in that the thin film (16) is formed of gold and has a thickness of less than 100 nm.
Claim 13
Dependent Claim
18 words
Sensor according to claim 1, characterized in that the detection particle (15) has the shape of a sphere.
Claim 14
Dependent Claim
24 words
Sensor according to claim 1, characterized in that the detection particle (15) has a pointed shape such as that of a cone or pyramid.
Claim 15
Dependent Claim
214 words
Apparatus for scanning the surface of a measured body by means of a sensor according to claim 1, wherein a measuring direction (20) is defined which, in the vicinity of the measurement site (18), is substantially normal to the surface (17) of the measured body (M), and a scanning direction (21) is defined which is substantially parallel to the surface (17) of the measured body (M), and wherein the sensor (S) and the measured body (M) are movable relative to each other in both said directions (20,21), characterized by a first control means (22) for controlling the relative movement of the sensor (S) in the scanning direction (21) according to a predetermined scanning pattern, a second control means (24) for controlling the relative movement of the sensor (S) in the measuring direction (20) in function of the detector signal and for delivering a positioning signal to a drive means (25) for said movement, a feedback line (12′) for delivering to the second control means (24) a feedback of the detector signal in order to keep the latter constant during a relative movement of the sensor (S) in the scanning direction (21), and a circuit (27) for delivering a measured value of the distance, said value being a function of the positioning signal. (Fig. 4)
Claim 16
Dependent Claim
167 words
Apparatus for scanning the surface of a measured body by means of a sensor according to claim 1, wherein a measuring direction (20) is defined which, in the vicinity of the measurement site (18), is substantially normal to the surface (17) of the measured body (M), and a scanning direction (21) is defined which is substantially parallel to the surface (17) of the measured body (M), and wherein the sensor (S) and the measured body (M) are movable relative to each other in said measuring direction (20) while being fixed relative to each other in any direction normal to the measuring direction (20), characterized by a control means (22) for controlling the relative movement of the sensor (S) in the scanning direction (21) according to a predetermined scanning pattern, a circuit (26) for delivering, during a relative movement of the sensor (S) in the scanning direction (21), a measured value of a variation of the distance, said value being a function of the detector signal. (Fig. 5)
Claim 17
Dependent Claim
187 words
Apparatus for scanning the surface of a measured body by means of a sensor according to claim 1, wherein a measuring direction (20) is defined which, in the vicinity of the measurement site (18), is substantially normal to the surface (17) of the measured body (M), and a scanning direction (21) is defined which is substantially parallel to the surface (17) of the measured body (M), and wherein the sensor (S) and the measured body (M) are movable relative to each other in both said directions (20,21), characterized by a control means (24) for controlling the relative movement of the sensor (S) in the measuring direction (20) in function of the detector signal and for delivering a positioning signal to a drive means (25) for said movement, a feedback line (12′) for delivering to the control means (24) a feedback of the detector signal in order to keep the latter constant during a relative movement of the sensor (S) in the measuring direction (20), and a circuit (27) for delivering a measured value of the distance, said value being a function of the positioning signal. (Fig. 6)
Claim 18
Dependent Claim
217 words
Apparatus for scanning the surface of a measured body by means of a sensor according to claim 1, wherein a measuring direction (20) is defined which, in the vicinity of the measurement site (18), is substantially normal to the surface (17) of the measured body (M), and a scanning direction (21) is defined which is substantially parallel to the surface (17) of the measured body (M), and wherein the sensor (S) and the measured body (M) are movable relative to each other in both said directions (20,21), characterized by a control means (24) for controlling the relative movement of the sensor (S) in the measuring direction (20) in function of the detector signal and for delivering a positioning signal to a drive means (25) for said movement, a circuit (28) for delivering an mean value signal representative of the value of the detector signal averaged over a predetermined time, a feedback line (12′) for delivering to the control means (24) the mean value signal in order to keep the latter constant during a relative movement of the sensor (S) in the measuring direction (20), and a circuit (29) for delivering a measured value of the distance, said value being a function of a difference between the detector signal and the mean value signal averaged therefrom. (Fig. 7)
Claim 19
Dependent Claim
57 words
Apparatus according to one of the claims 14 to 17 for scanning the surface of a measured body (M) whose surface (17) is convex, characterized by a sensor body (1) whose surface (5) has at least one straight generatrix passing through that location (14) of the surface (5) where the detection particle (15) is located. (Fig. 2)
Claim 20
Dependent Claim
62 words
Apparatus according to one of the claims 14 to 17 for scanning the surface of a measured body (M) whose surface (17) is substantially plane, characterized by a sensor body (1) having a surface (5) which is convex towards the measured body (M) at least at that location (14) of the surface (5) where the detection particle (15) is located. (Fig. 3)
Claim 21
Dependent Claim
26 words
Apparatus according to one of the claims 14 to 17, characterized in that the laser light (2) directed to enter the sensor body (1) is p-polarized.
References Cited (Backward Citations)
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