GB2061548A - Optical Position Sensor - Google Patents
Optical Position Sensor Download PDFInfo
- Publication number
- GB2061548A GB2061548A GB8031590A GB8031590A GB2061548A GB 2061548 A GB2061548 A GB 2061548A GB 8031590 A GB8031590 A GB 8031590A GB 8031590 A GB8031590 A GB 8031590A GB 2061548 A GB2061548 A GB 2061548A
- Authority
- GB
- United Kingdom
- Prior art keywords
- block
- light
- position sensor
- array
- light source
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 26
- 239000000463 material Substances 0.000 claims abstract description 8
- 238000000576 coating method Methods 0.000 abstract description 3
- 239000011521 glass Substances 0.000 abstract description 2
- 239000004033 plastic Substances 0.000 abstract description 2
- 229920003023 plastic Polymers 0.000 abstract description 2
- 239000011248 coating agent Substances 0.000 abstract 1
- 230000005855 radiation Effects 0.000 description 4
- 238000010586 diagram Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S3/00—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received
- G01S3/78—Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic, or electromagnetic waves, or particle emission, not having a directional significance, are being received using electromagnetic waves other than radio waves
- G01S3/782—Systems for determining direction or deviation from predetermined direction
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B11/00—Measuring arrangements characterised by the use of optical techniques
- G01B11/26—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes
- G01B11/27—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes
- G01B11/272—Measuring arrangements characterised by the use of optical techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes using photoelectric detection means
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
Abstract
An optical position sensor comprises a light source (5) mounted on one body (1) and arranged to direct a beam of light onto a light sensor array (11) mounted on another body (3) to provide an indication of the relative positions of the two bodies; one or both of the light source (5) and sensor array (11) being associated with an optical system comprising a block (13, 23) of light transmissive material having a curved internally reflecting surface (19, 29). As described, the light source (5) is an infra red LED, the sensor (11) is a charge coupled device, and the blocks (13, 23) are glass or plastics with a silvered or interference coating on their curved surfaces (19, 29). To restrict light to small angles, the surfaces (21, 27) of the blocks may be fresnel surfaces. The arrangement may be used in aircraft to measure changes in the alignment of a wing mounted component of a weapon relative to the fuselage. <IMAGE>
Description
SPECIFICATION
Optical Position Sensors
This invention relates to optical position sensors.
The invention relates particularly to optical position sensors of the kind comprising a light source mounted on a first body and arranged to direct a beam of light onto a light sensor array mounted on a second body to provide an indication of the position at which said beam impinges on the array and hence of the relative positions of the first and second bodies. Such an optical position sensor is hereinafter referred to as a position sensor of the kind specified.
In a position sensor of the kind specified the light source is associated with an optical system whereby the light emitted by the source is formed into a beam directed towards the sensor array, and the sensor array is similarly associated with an optical system whereby the received beam is directed onto the array.
It is an object of the present invention to provide a position sensor of the kind specified incorporating an improved form of optical system for the light source and/or the light sensor array.
According to one aspect of the invention, in a position sensor of the kind specified the light source is associated with an optical system comprising a block of light transmissive material, the light source being disposed adjacent a first surface of the block, and the block having a curved internally reflecting second surface which serves to direct light rays received from said surce through the block towards a third refracting surface of the block such that the rays exit the block in a beam directed towards the light sensor array.
According to a second aspect of the invention in a position sensor of the kind specified the light sensor array is associated with an optical system comprising a block of light transmissive material having a first surface adjacent which the array is positioned and a curved internally reflecting second surface which serves to form light rays from said source entering the block via a third refracting surface of the block into a beam directed onto said array.
In one particular arrangement according to either aspect of the invention said third surface constitutes a fresnel lens surface.
The light source or sensor array is suitably located in a recess formed in the block.
The second surface of the block is suitably spherical or parabolic.
One optical position sensor in accordance with the invention will now be described, by way of example with reference to the accompanying drawing in which: Figure 1 is a schematic diagram of the sensor; and
Figure 2 illustrates a modification of the sensor.
Referring to the drawing, the sensor is arranged to produce an output representative of changes in the position of a first body 1 relative to a second body 3 in a direction perpendicular to the plane of the drawing.
The sensor includes an infra red radiation source 5, e.g. a light emitting diode, mounted on the body 1 and associated with an optical system 7 whereby a collimated or focussed beam of radiation from the source 5 is directed towards the second body 3.
On the second body, where the beam impinges, there is mounted a further optical system 9 which serves to focus the beam onto a linear array of infra red sensors 1 the arrangement being such that radiation from the source 5 is focussed onto the sensor array 11 over the whole range of possible relative movement of the two bodies 1 and 3. In the drawing the sensor array is shown end-on.
The sensor array is suitably a charge-coupled device (CCD) of the kind comprising a linear array of elements each of which is arranged to store an electric charge representative of the intensity of infra red radiation falling onto it. The stored charge pattern can be read out from the CCD, when desired, by a sequential clocking process similar to that employed with a shift register.
The optical system 7 comprises a block 1 3 of light transmissive material, e.g. glass or a plastics material, secured to the body by clamping means 1 5. The source 5 is housed in a recess in one face 17 of the block 13. Light rays emitted by the source 5 pass through the block to a second parabolic face 1 9 of the block where they are reflected to form a collimated or focussed beam directed towards a third substantially planar face 21 of the block 1 3 which is flush with the external surface of the body. At the third face 21 the rays pass out of the block 1 3 and are refracted to form a beam directed to the optical system 9 on the body 3.
-The optical system 9 comprises a similar block 23 of light transmissive material with the array 11 located in a recess formed in one face 25. Light rays from the source 5 enter the block 23 at a substantially planar face 27 flush with the external surface of the body 3, and are internally reflected at a parabolic face 29 to form a beam focussed onto the array 11.
It will be apparent that as the two bodies move relatively the position of the focussed beam on the array 11 changes correspondingly. The array 11 produces an output representative of the position of impingement of the beam on the array and hence of the relative positions of the two bodies 1 and 3 in the aforementioned direction.
The required reflectiv properties at the faces 19 and 29 of the blocks 13 and 17 may be provided by conventional reflective coatings e.g.
silvering. Alternatively multi-layer reflective coatings tuned to the wavelength of the source 5 may be used.
Compared with lens arrangements the optical systems 7 and 9 have the advantages that they exhibit a high numerical aperture, are not susceptible to dirt or damage and provide a compact installation flush with the surface of the associated body.
If it is desired to emit light from the block 1 3 at a small angle to the face 21 , the face 21 may be provided with corrugations extending in a direction perpendicular to the plane of the drawing so as to act as a fresnel lens, as illustrated in Figure 2. The face 27 of block 23 may be similarly modified to allow light from the source 5 to be incident on the face at a small angle.
It is further pointed out that the faces 21 and 27 may, if desired, be slightly curved to conform to the surfaces of the bodies 1 and 3 respectively.
One particular application envisaged for the invention is in an aircraft weapon system for measuring changes in the alignment of a wing mounted component of the weapon system relative to an axis fixed with respect to the aircraft fuselage due to wing fiexing, such a system being described in U.K. Patent Specification No.
1,554,010.
Claims (9)
1. A position sensor of the kind specified wherein the light source is associated with an optical system comprising a block of light transmissive material, the light source being disposed adjacent a first surface of the block, and the block having a curved internally reflecting second surface which serves to direct light rays received from said source through the block towards a third refracting surface of the block such that the rays exit the block in a beam directed towards the light sensor array.
2. A position sensor according to Claim 1 wherein said light source is located in a recess formed in the block.
3. A position sensor of the kind specified wherein the light sensor array is associated with an optical system comprising a block of light transmissive material having a first surface adjacent which the array is positioned and a curved internally reflecting second surface which serves to form light rays from said source entering the block via a third refracting surface of the block into a beam directed onto said array.
4. A position sensor according to Claim 3 wherein said sensor array is located in a recess formed in the block.
5. A position sensor according to any preceding claim wherein said third surface constitutes a fresnel lens surface.
6. A position sensor according to any preceding claim wherein said second surface of the block is spherical or parabolic.
7. An optical position sensor of the kind specified having a light source and associated optical system substantially as hereinbefore described with reference to Figure 1 or Figure 2.
8. An optical position sensor of the kind specified having a sensor array and associated optical system substantially as hereinbefore described with reference to Figure 1 or Figure 2.
9. An optical position sensor substantially as hereinbefore described with reference to Figure 1 or Figure 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8031590A GB2061548B (en) | 1979-10-10 | 1980-10-01 | Optical position sensor |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB7935212 | 1979-10-10 | ||
| GB8031590A GB2061548B (en) | 1979-10-10 | 1980-10-01 | Optical position sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2061548A true GB2061548A (en) | 1981-05-13 |
| GB2061548B GB2061548B (en) | 1983-11-09 |
Family
ID=26273154
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8031590A Expired GB2061548B (en) | 1979-10-10 | 1980-10-01 | Optical position sensor |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2061548B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0762139A2 (en) * | 1995-09-08 | 1997-03-12 | Sextant Avionique | Optical device for the determination of the orientation of a solid |
| WO2009076944A3 (en) * | 2007-12-18 | 2009-09-24 | Epcos Ag | Radiation sensor for detecting the position and intensity of a radiation source |
-
1980
- 1980-10-01 GB GB8031590A patent/GB2061548B/en not_active Expired
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0762139A2 (en) * | 1995-09-08 | 1997-03-12 | Sextant Avionique | Optical device for the determination of the orientation of a solid |
| FR2738628A1 (en) * | 1995-09-08 | 1997-03-14 | Sextant Avionique | OPTICAL DEVICE FOR DETERMINING THE ORIENTATION OF A SOLID |
| EP0762139A3 (en) * | 1995-09-08 | 1997-03-19 | Sextant Avionique | Optical device for the determination of the orientation of a solid |
| US5767524A (en) * | 1995-09-08 | 1998-06-16 | Sextant Avionique | Optical device for determining the orientation of a solid body |
| WO2009076944A3 (en) * | 2007-12-18 | 2009-09-24 | Epcos Ag | Radiation sensor for detecting the position and intensity of a radiation source |
| US8149389B2 (en) | 2007-12-18 | 2012-04-03 | Epcos Ag | Radiation sensor for detecting the position and intensity of a radiation source |
| EP2629112A1 (en) * | 2007-12-18 | 2013-08-21 | Epcos Ag | Radiation sensor for detecting the position and intensity of a radiation source |
| US8705014B2 (en) | 2007-12-18 | 2014-04-22 | Epcos Ag | Radiation sensor for detecting the position and intensity of a radiation source |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2061548B (en) | 1983-11-09 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |