CA2236772C - Focusing-type calculating means - Google Patents
Focusing-type calculating means Download PDFInfo
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- CA2236772C CA2236772C CA002236772A CA2236772A CA2236772C CA 2236772 C CA2236772 C CA 2236772C CA 002236772 A CA002236772 A CA 002236772A CA 2236772 A CA2236772 A CA 2236772A CA 2236772 C CA2236772 C CA 2236772C
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- shaped
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- calculating device
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- 230000001133 acceleration Effects 0.000 abstract 1
- 238000009826 distribution Methods 0.000 description 11
- 238000010586 diagram Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- 230000001419 dependent effect Effects 0.000 description 1
- 230000001066 destructive effect Effects 0.000 description 1
- 239000005337 ground glass Substances 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 102220151991 rs886061744 Human genes 0.000 description 1
- 239000012780 transparent material Substances 0.000 description 1
Classifications
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M1/00—Analogue/digital conversion; Digital/analogue conversion
- H03M1/12—Analogue/digital converters
- H03M1/22—Analogue/digital converters pattern-reading type
- H03M1/24—Analogue/digital converters pattern-reading type using relatively movable reader and disc or strip
- H03M1/28—Analogue/digital converters pattern-reading type using relatively movable reader and disc or strip with non-weighted coding
- H03M1/30—Analogue/digital converters pattern-reading type using relatively movable reader and disc or strip with non-weighted coding incremental
- H03M1/301—Constructional details of parts relevant to the encoding mechanism, e.g. pattern carriers, pattern sensors
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- 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
- G01D5/32—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 with attenuation or whole or partial obturation of beams of light
- G01D5/34—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 with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/347—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 with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells using displacement encoding scales
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- 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
- G01D5/32—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 with attenuation or whole or partial obturation of beams of light
- G01D5/34—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 with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/36—Forming the light into pulses
- G01D5/38—Forming the light into pulses by diffraction gratings
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- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Theoretical Computer Science (AREA)
- Optical Transform (AREA)
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
- Position Input By Displaying (AREA)
- Length Measuring Devices By Optical Means (AREA)
Abstract
A focusing-type calculating device comprising a light source, a grating wheel, and a photo-detector. The input plane of the grating wheel has a ring-shaped lens to focus the light emitted from the light source. The output plane of the grating wheel has a plurality of tooth-shaped lenses perpendicular to the ring-shaped lens, which can focus the working beams after the working beams pass through the output plane, thus minimizing interference. The device can be used for detecting the position, speed and acceleration of a moving or rotating object such as a computer mouse.
Description
FOCUSING-TYPE CALCULATING DEVICE
FIELD OF THE INVENTION
The present invention relates to a focusing-type calculating device, more particularly, to an encoder which can prevent constructive and destructive interference when light is emitted toward a photo-detector through a grating wheel.
BACKGROUND OF THE INVENTION
The conventional optical encoder, shown in FIG. l, is a blocking-type encoder. The encoder comprises a grating wheel 60, a light source 70, and a photo-detector 80. The light source 70 is arranged near the grating wheel 60 so as to emit light toward the grating wheel 60. The grating wheel 60 is centered on an axis 50 and is rotated by a driving means (not shown). The grating wheel 60 is provided with a plurality of slits 61 along the distal portion thereof. Moreover, there is an opaque section 62 arranged between two adjacent slits 61.
The photo-detector 80 is placed at the proximity of the grating wheel 60 and comprises a photo-sensitive chip 81 to receive the light emitted from the slit 60.
The light emitted from light source 70 is chopped by slit 61 and opaque section 62 of grating wheel 60, and becomes a working beam when grating wheel 60 is rotated. The working beam is detected by photo-detector 80 and is converted to a sinusoidal signal on an oscilloscope. The signal is processed by a rectifier to form four signals (0, 0) , (0, 1) , (1, 1) , (1, 0) .
However, due to the wave nature of light, light emitted from two slits may interfere with each other, as shown in FIG. 2. This interference may cause a malfunction in photo-detector 80.
To eliminate the interference caused by the two adjacent slits, one may bring the photo-sensitive chip 81 of photo-detector 80 near slit 61. Another approach is to make the area of slit 61 larger than that of the photo-sensitive chip 81 (an increase of at least a third). However, the first approach makes fabrication complicated and difficult, while the second approach degrades resolution.
As shown in FIG. 3A, D represents the light source, C is the grating, A and B are the two slits, and S is the photo detector, which moves along direction T. FIG. 3B shows the distribution of light intensity, where N1 and Nz represent average intensity distributions and H represents probability.
As shown in FIG. 3B, N1= (Hl) 2 is the average intensity distribution detected by photo-detector S, when slit B is blocked. Moreover, N2=(H2)2 is the average intensity distributions detected by photo-detector S when slit A is blocked.
If the light passing through slits A and B does not interfere, the light intensity distribution detected by photo-detector S will be N12=Nl+N2, as shown in FIG. 3C.
However, according to the principles of wave optics, the light intensity distribution detected by photo-detector S is that shown in FIG. 4, due to the interference between two slits.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a focusing-type calculating device having a ring-shaped lens which is arranged on the input plane of a grating wheel in order to focus the light emitted from the light source.
Further, a plurality of tooth-shaped lenses are provided, each being perpendicular to the ring-shaped lens and are arranged on the output plane of the grating wheel to focus the working beam after the working beam has passed through the output plane, thus minimizing the interference.
Another object of the present invention is to provide a focusing-type calculating device in which the photo-sensitive chip can be positioned farther from the output plane of the grating wheel without increasing fabrication complexity or reducing resolution.
According to the present invention, there is provided a focusing-type calculating device comprising:
a light source producing light;
a grating wheel having a ring-shaped condensing lens formed on a circumference of an input plane thereon, the light emitted from the light source being condensed by said ring-shaped condensing lens of said grating wheel, and a plurality of tooth-shaped condensing lenses perpendicular to said ring-shaped condensing lens and radially formed on a circumference of an output plane of said grating wheel opposite to said input plane, said tooth-shaped condensing lenses condensing the light again, thus minimizing interference; and a photo-detector having a set of photo-sensitive chips for detecting the light passing through said grating wheel, said photo-detector being located between said toothed-shaped lenses and a focal point thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings in which:
FIG. 1 shows a conventional blocking-type photo encoder;
FIG. 2 shows the light intensity distribution caused by two-slit interference;
FIELD OF THE INVENTION
The present invention relates to a focusing-type calculating device, more particularly, to an encoder which can prevent constructive and destructive interference when light is emitted toward a photo-detector through a grating wheel.
BACKGROUND OF THE INVENTION
The conventional optical encoder, shown in FIG. l, is a blocking-type encoder. The encoder comprises a grating wheel 60, a light source 70, and a photo-detector 80. The light source 70 is arranged near the grating wheel 60 so as to emit light toward the grating wheel 60. The grating wheel 60 is centered on an axis 50 and is rotated by a driving means (not shown). The grating wheel 60 is provided with a plurality of slits 61 along the distal portion thereof. Moreover, there is an opaque section 62 arranged between two adjacent slits 61.
The photo-detector 80 is placed at the proximity of the grating wheel 60 and comprises a photo-sensitive chip 81 to receive the light emitted from the slit 60.
The light emitted from light source 70 is chopped by slit 61 and opaque section 62 of grating wheel 60, and becomes a working beam when grating wheel 60 is rotated. The working beam is detected by photo-detector 80 and is converted to a sinusoidal signal on an oscilloscope. The signal is processed by a rectifier to form four signals (0, 0) , (0, 1) , (1, 1) , (1, 0) .
However, due to the wave nature of light, light emitted from two slits may interfere with each other, as shown in FIG. 2. This interference may cause a malfunction in photo-detector 80.
To eliminate the interference caused by the two adjacent slits, one may bring the photo-sensitive chip 81 of photo-detector 80 near slit 61. Another approach is to make the area of slit 61 larger than that of the photo-sensitive chip 81 (an increase of at least a third). However, the first approach makes fabrication complicated and difficult, while the second approach degrades resolution.
As shown in FIG. 3A, D represents the light source, C is the grating, A and B are the two slits, and S is the photo detector, which moves along direction T. FIG. 3B shows the distribution of light intensity, where N1 and Nz represent average intensity distributions and H represents probability.
As shown in FIG. 3B, N1= (Hl) 2 is the average intensity distribution detected by photo-detector S, when slit B is blocked. Moreover, N2=(H2)2 is the average intensity distributions detected by photo-detector S when slit A is blocked.
If the light passing through slits A and B does not interfere, the light intensity distribution detected by photo-detector S will be N12=Nl+N2, as shown in FIG. 3C.
However, according to the principles of wave optics, the light intensity distribution detected by photo-detector S is that shown in FIG. 4, due to the interference between two slits.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a focusing-type calculating device having a ring-shaped lens which is arranged on the input plane of a grating wheel in order to focus the light emitted from the light source.
Further, a plurality of tooth-shaped lenses are provided, each being perpendicular to the ring-shaped lens and are arranged on the output plane of the grating wheel to focus the working beam after the working beam has passed through the output plane, thus minimizing the interference.
Another object of the present invention is to provide a focusing-type calculating device in which the photo-sensitive chip can be positioned farther from the output plane of the grating wheel without increasing fabrication complexity or reducing resolution.
According to the present invention, there is provided a focusing-type calculating device comprising:
a light source producing light;
a grating wheel having a ring-shaped condensing lens formed on a circumference of an input plane thereon, the light emitted from the light source being condensed by said ring-shaped condensing lens of said grating wheel, and a plurality of tooth-shaped condensing lenses perpendicular to said ring-shaped condensing lens and radially formed on a circumference of an output plane of said grating wheel opposite to said input plane, said tooth-shaped condensing lenses condensing the light again, thus minimizing interference; and a photo-detector having a set of photo-sensitive chips for detecting the light passing through said grating wheel, said photo-detector being located between said toothed-shaped lenses and a focal point thereof.
BRIEF DESCRIPTION OF THE DRAWINGS
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawings in which:
FIG. 1 shows a conventional blocking-type photo encoder;
FIG. 2 shows the light intensity distribution caused by two-slit interference;
FIG. 3A shows a two-slit interference set-up;
FIG. 3B shows the light intensity distribution measured by the set-up of FIG. 3A;
FIG. 3C is a non-realistic plot of the light intensity distribution measured by the set-up of FIG. 3A when both slits are open;
FIG. 4 is a realistic plot of the light intensity distribution measured by the set-up of FIG. 3A when both slits are open;
FIG. 5 shows the focusing of the working beam according to the present invention;
FIG. 6 shows a schematic diagram of the present invention;
FIG. 7 and 7A show the front view and side view of the present invention;
FIG. 8A-D show the four signals (0,0), (0,1), (1,1), (1,0) appearing on oscilloscope when the wheel of the present invention rotates;
FIG. 9 and 9A show the front view and side view of another embodiment of the present invention;
FIG. 10 and 10A show the front view and both side views of a third embodiment of the present invention;
FIG. 11 and 11A show the front view and side view of a fourth embodiment of the present invention;
FIG. 12 and 12A are schematic diagrams showing the tooth-shaped lens replaced by a convex tooth-shaped lens;
FIG. 13 and 13A are schematic diagrams showing the tooth-shaped lens replaced by a strip-shaped lens; and FIG. 14 and 14A are schematic diagrams showing the tooth-shaped lens replaced by a tapered lens.
FIG. 3B shows the light intensity distribution measured by the set-up of FIG. 3A;
FIG. 3C is a non-realistic plot of the light intensity distribution measured by the set-up of FIG. 3A when both slits are open;
FIG. 4 is a realistic plot of the light intensity distribution measured by the set-up of FIG. 3A when both slits are open;
FIG. 5 shows the focusing of the working beam according to the present invention;
FIG. 6 shows a schematic diagram of the present invention;
FIG. 7 and 7A show the front view and side view of the present invention;
FIG. 8A-D show the four signals (0,0), (0,1), (1,1), (1,0) appearing on oscilloscope when the wheel of the present invention rotates;
FIG. 9 and 9A show the front view and side view of another embodiment of the present invention;
FIG. 10 and 10A show the front view and both side views of a third embodiment of the present invention;
FIG. 11 and 11A show the front view and side view of a fourth embodiment of the present invention;
FIG. 12 and 12A are schematic diagrams showing the tooth-shaped lens replaced by a convex tooth-shaped lens;
FIG. 13 and 13A are schematic diagrams showing the tooth-shaped lens replaced by a strip-shaped lens; and FIG. 14 and 14A are schematic diagrams showing the tooth-shaped lens replaced by a tapered lens.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
According to the principles of wave optics, the light intensity distribution detected by photo-detector S is that shown in FIG. 4, due to the interference between two slits.
To eliminate this interference, one may route the light by a path which does not pass through the slits. Another method is to focus the light before it reaches the photo detector. As shown in FIG. 5, the photo-detector can be placed between the lens and the focal point of the lens to eliminate the interference phenomenon.
As shown in FIGS. 6 and 7, the focusing-type calculating device according to the present invention comprises a light source 1, a grating wheel 2, and a photo-detector 3. The light source 1 is arranged in proximity to the grating wheel 2, thus light emitted from the light source 1 will impinge upon the input plane 22 of grating wheel 2.
The grating wheel 2 is rotatably arranged on an axis 21, through the center thereof, and is rotated by a driving means (not shown). A ring-shaped lens 24, with radius of curvature R1, is arranged on the input plane 22 of grating wheel 2 to focus the light emitted from the light source 1. A plurality of tooth-shaped lenses 25, each with radius of curvature R2, are arranged on the output plane 23 of grating wheel 2. The tooth-shaped lenses 25 have a total internal reflection angle smaller than 41.8° and are positioned perpendicular to the ring-shaped lens 24. According to the lens formula 1/f=(1/R1+1/R2)(m-1), the focal length f is dependent upon R1 and R2.
The photo-detector 3 is made of transparent material and positioned between tooth-shaped lenses 25 and the focal point of the tooth-shaped lenses 25, and further positioned opposite of light source 1, The photo-detector 3 comprises upper and lower photo-sensitive chips 31 in order to receive the working beam emitted from the output plane 23.
When the working beam impinges upon the input plane 22 of the wheel 2, the ring-shaped lens 24 will focus the beam.
After the working beam passes through the output plane 23, the tooth-shaped lenses 25 refocus the beam. Thus, the problem of interference is minimized when the working beam reaches the photo-sensitive chips 31 of the photo-detector 3.
When the grating wheel 2 rotates, light emitted from the light source 1 is chopped by grating wheel 2 and forms a working beam. The working beam is detected by the photo detector 3 and is subsequently converted to a sinusoidal signal on an oscilloscope. The signal is processed by a rectifier to form the four signals (0,0), (0,1), (1,1), (1,0), as shown in FIG. 1.
As shown in FIG. 9, the input plane 22 can be a planar shape and focusing is achieved by the tooth-shaped lenses 25.
As shown in FIG. 10, the output plane 25 can be provided with a plurality of tooth-shaped surfaces, the light emitted from the light source 1 being focused by ring-shaped lens 24.
As shown in FIG. 11, the input plane can be a planar shape, and the output plane 25 can be provided with a plurality of tooth-shaped surfaces.
As shown in FIGS. 12-14, the tooth-shaped lenses 25 can be replaced by a set of convex tooth-shaped lenses, as shown in FIG. 12, strip-shaped lenses as shown in FIG. 13, or a set of tapered lenses, as shown in FIG. 14, in order to focus the working beam after the working beam passes through the output plane, thus minimizing the interference.
The convex portion 253 or concave portion 251 of the strip-shaped lens or the tapered lens can be coated with a reflective medium, an opaque medium, or can be ground to form ground glass in order to reflect unwanted or interfering external light when the working beam is in operation.
In summary, the present invention minimizes the interference when the working beam reaches the photo-sensitive chip of the photo-detector due to the focusing of the beam.
Although the present has been described with reference to the two preferred embodiments thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the above description, and others may be obvious to those skilled in the art. All such substitutions and modifications are intended to be encompassed within the scope of the invention as defined in the Claims.
According to the principles of wave optics, the light intensity distribution detected by photo-detector S is that shown in FIG. 4, due to the interference between two slits.
To eliminate this interference, one may route the light by a path which does not pass through the slits. Another method is to focus the light before it reaches the photo detector. As shown in FIG. 5, the photo-detector can be placed between the lens and the focal point of the lens to eliminate the interference phenomenon.
As shown in FIGS. 6 and 7, the focusing-type calculating device according to the present invention comprises a light source 1, a grating wheel 2, and a photo-detector 3. The light source 1 is arranged in proximity to the grating wheel 2, thus light emitted from the light source 1 will impinge upon the input plane 22 of grating wheel 2.
The grating wheel 2 is rotatably arranged on an axis 21, through the center thereof, and is rotated by a driving means (not shown). A ring-shaped lens 24, with radius of curvature R1, is arranged on the input plane 22 of grating wheel 2 to focus the light emitted from the light source 1. A plurality of tooth-shaped lenses 25, each with radius of curvature R2, are arranged on the output plane 23 of grating wheel 2. The tooth-shaped lenses 25 have a total internal reflection angle smaller than 41.8° and are positioned perpendicular to the ring-shaped lens 24. According to the lens formula 1/f=(1/R1+1/R2)(m-1), the focal length f is dependent upon R1 and R2.
The photo-detector 3 is made of transparent material and positioned between tooth-shaped lenses 25 and the focal point of the tooth-shaped lenses 25, and further positioned opposite of light source 1, The photo-detector 3 comprises upper and lower photo-sensitive chips 31 in order to receive the working beam emitted from the output plane 23.
When the working beam impinges upon the input plane 22 of the wheel 2, the ring-shaped lens 24 will focus the beam.
After the working beam passes through the output plane 23, the tooth-shaped lenses 25 refocus the beam. Thus, the problem of interference is minimized when the working beam reaches the photo-sensitive chips 31 of the photo-detector 3.
When the grating wheel 2 rotates, light emitted from the light source 1 is chopped by grating wheel 2 and forms a working beam. The working beam is detected by the photo detector 3 and is subsequently converted to a sinusoidal signal on an oscilloscope. The signal is processed by a rectifier to form the four signals (0,0), (0,1), (1,1), (1,0), as shown in FIG. 1.
As shown in FIG. 9, the input plane 22 can be a planar shape and focusing is achieved by the tooth-shaped lenses 25.
As shown in FIG. 10, the output plane 25 can be provided with a plurality of tooth-shaped surfaces, the light emitted from the light source 1 being focused by ring-shaped lens 24.
As shown in FIG. 11, the input plane can be a planar shape, and the output plane 25 can be provided with a plurality of tooth-shaped surfaces.
As shown in FIGS. 12-14, the tooth-shaped lenses 25 can be replaced by a set of convex tooth-shaped lenses, as shown in FIG. 12, strip-shaped lenses as shown in FIG. 13, or a set of tapered lenses, as shown in FIG. 14, in order to focus the working beam after the working beam passes through the output plane, thus minimizing the interference.
The convex portion 253 or concave portion 251 of the strip-shaped lens or the tapered lens can be coated with a reflective medium, an opaque medium, or can be ground to form ground glass in order to reflect unwanted or interfering external light when the working beam is in operation.
In summary, the present invention minimizes the interference when the working beam reaches the photo-sensitive chip of the photo-detector due to the focusing of the beam.
Although the present has been described with reference to the two preferred embodiments thereof, it will be understood that the invention is not limited to the details thereof. Various substitutions and modifications have been suggested in the above description, and others may be obvious to those skilled in the art. All such substitutions and modifications are intended to be encompassed within the scope of the invention as defined in the Claims.
Claims (10)
1. A focusing-type calculating device comprising:
a light source producing light;
a grating wheel having a ring-shaped condensing lens formed on a circumference of an input plane thereon, the light emitted from the light source being condensed by said ring-shaped condensing lens of said grating wheel, and a plurality of tooth-shaped condensing lenses perpendicular to said ring-shaped condensing lens and radially formed on a circumference of an output plane of said grating wheel opposite to said input plane, said tooth-shaped condensing lenses condensing the light again, thus minimizing interference; and a photo-detector having a set of photo-sensitive chips for detecting the light passing through said grating wheel, said photo-detector being located between said toothed-shaped lenses and a focal point thereof.
a light source producing light;
a grating wheel having a ring-shaped condensing lens formed on a circumference of an input plane thereon, the light emitted from the light source being condensed by said ring-shaped condensing lens of said grating wheel, and a plurality of tooth-shaped condensing lenses perpendicular to said ring-shaped condensing lens and radially formed on a circumference of an output plane of said grating wheel opposite to said input plane, said tooth-shaped condensing lenses condensing the light again, thus minimizing interference; and a photo-detector having a set of photo-sensitive chips for detecting the light passing through said grating wheel, said photo-detector being located between said toothed-shaped lenses and a focal point thereof.
2. The focusing-type calculating device according to claim 1, wherein the tooth-shaped lenses have a total internal reflection angle smaller than 41.8°.
3. The focusing-type calculating device according to claim 1, wherein said input plane of said grating wheel is of planar shape.
4. The focusing-type calculating device according to claim 1, wherein said output plane of said grating wheel is provided with a plurality of tooth-shaped surfaces.
5. The focusing-type calculating device according to claim 1, wherein said input plane of said grating wheel is of planar shape, and said output plane of said grating wheel is provided with a plurality of tooth-shaped surfaces.
6. The focusing-type calculating device according to claim 1, wherein said tooth-shaped lenses comprise convex tooth-shaped lenses.
7. The focusing-type calculating device according to claim 1, wherein said tooth-shaped lenses comprise strip-shaped lenses.
8. The focusing-type calculating device according to claim 7, wherein said strip-shaped lenses have a convex portion or a concave portion at least partially coated with a photo-reflective medium, an opaque medium, or ground.
9. The focusing-type calculating device according to claim 1, wherein said tooth-shaped lenses comprise tapered lenses.
10. The focusing-type calculating device according to claim 9, wherein said tapered lenses have a convex portion or a concave portion at least partially coated with a photo-reflective medium, an opaque medium, or ground.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002236772A CA2236772C (en) | 1998-06-02 | 1998-06-02 | Focusing-type calculating means |
| DE19826009A DE19826009C2 (en) | 1998-06-02 | 1998-06-10 | Optical encoder |
| FR9807290A FR2779815A1 (en) | 1998-06-02 | 1998-06-10 | Non-interference rotary encoder |
| GB9812912A GB2338549A (en) | 1998-06-02 | 1998-06-15 | A Rotary Encoder |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002236772A CA2236772C (en) | 1998-06-02 | 1998-06-02 | Focusing-type calculating means |
| DE19826009A DE19826009C2 (en) | 1998-06-02 | 1998-06-10 | Optical encoder |
| FR9807290A FR2779815A1 (en) | 1998-06-02 | 1998-06-10 | Non-interference rotary encoder |
| GB9812912A GB2338549A (en) | 1998-06-02 | 1998-06-15 | A Rotary Encoder |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2236772A1 CA2236772A1 (en) | 1999-12-02 |
| CA2236772C true CA2236772C (en) | 2003-07-29 |
Family
ID=32966513
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002236772A Expired - Fee Related CA2236772C (en) | 1998-06-02 | 1998-06-02 | Focusing-type calculating means |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA2236772C (en) |
| DE (1) | DE19826009C2 (en) |
| FR (1) | FR2779815A1 (en) |
| GB (1) | GB2338549A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101514909B (en) * | 2008-02-22 | 2011-07-27 | 鸿富锦精密工业（深圳）有限公司 | Optical code disc and corresponding optical encoder |
| CN101709982B (en) * | 2009-11-05 | 2011-06-15 | 无锡鑫亚电子有限公司 | Rotary encoder |
Family Cites Families (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR77221E (en) * | 1960-02-23 | 1962-02-02 | Levallois Optique Et Prec | Photoelectric camera for checking or controlling positions |
| GB991873A (en) * | 1961-12-04 | 1965-05-12 | Hensoldt & Soehne Optik | Equipment for indicating the amount of the displacement of a moving part |
| DE2543668A1 (en) * | 1974-10-10 | 1976-04-22 | Papst Motoren Kg | INCREMENTALLY ADJUSTABLE DRIVE |
| GB2049165A (en) * | 1979-05-08 | 1980-12-17 | Pye Ltd | Dual beam spectrophotometer |
| US4528448A (en) * | 1982-05-13 | 1985-07-09 | Benson, Inc. | Plane linear grating for optically encoding information |
| JPS5963517A (en) * | 1982-10-04 | 1984-04-11 | Nippon Kogaku Kk <Nikon> | Photoelectric encoder |
| JPS6070311A (en) * | 1983-09-27 | 1985-04-22 | Mitsubishi Electric Corp | Optical type encoder |
| JPH087082B2 (en) * | 1990-09-05 | 1996-01-29 | 松下電器産業株式会社 | Optical encoder |
| JP3170902B2 (en) * | 1992-09-30 | 2001-05-28 | キヤノン株式会社 | Signal processing method and encoder using the same |
| JPH08201114A (en) * | 1995-01-24 | 1996-08-09 | Matsushita Electric Ind Co Ltd | Optical encoder |
| JPH10239108A (en) * | 1997-02-21 | 1998-09-11 | Fanuc Ltd | Optical encoder |
-
1998
- 1998-06-02 CA CA002236772A patent/CA2236772C/en not_active Expired - Fee Related
- 1998-06-10 FR FR9807290A patent/FR2779815A1/en active Pending
- 1998-06-10 DE DE19826009A patent/DE19826009C2/en not_active Expired - Fee Related
- 1998-06-15 GB GB9812912A patent/GB2338549A/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| FR2779815A1 (en) | 1999-12-17 |
| CA2236772A1 (en) | 1999-12-02 |
| DE19826009A1 (en) | 1999-12-16 |
| GB2338549A (en) | 1999-12-22 |
| DE19826009C2 (en) | 2002-06-20 |
| GB9812912D0 (en) | 1998-08-12 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |