Optical encoder, servo motor, and positioning method for optical encoder
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- DELTA ELECTRONICS INC(CN)
- Filing Date
- 2024-12-23
- Publication Date
- 2026-07-02
Smart Images
Figure CN2024141635_02072026_PF_FP_ABST
Abstract
Description
Optical encoders, servo motors, and positioning methods for optical encoders Technical Field
[0001] This disclosure relates to an encoder, a servo motor, and a positioning method for the encoder, and more particularly to an optical encoder, a servo motor, and a positioning method for the optical encoder. Background Technology
[0002] Servo motors typically acquire position information through encoders, thereby achieving high-resolution and high-precision control. The sensors on the encoder obtain position information by sensing real physical quantities (such as light energy or magnetic flux density) generated by a scale (or encoder disk). The accuracy of the position information usually depends on the precision of the patterns on the scale and the quality of the signal generated by the sensor.
[0003] Typical optical encoders are optical transmission encoders, which obtain incremental position information through a light source, scale, and sensor. However, optical transmission encoders have a complex structure, are difficult to manufacture and maintain, and are expensive.
[0004] Therefore, improving the accuracy of optical encoders, simplifying their structure, and obtaining absolute position information are among the pressing issues that need to be addressed. Summary of the Invention
[0005] This disclosure provides an optical encoder, a servo motor, and a positioning method for the optical encoder, which can improve the accuracy of the optical encoder, simplify its structure, and obtain absolute position information.
[0006] This disclosure provides an optical encoder including a code disk unit comprising N first unit patterns arranged in an array, each first unit pattern including a high-reflection area and a low-reflection area, where N is a positive integer; an optical sensing unit corresponding to the code disk unit, including a light-emitting element and a first sensing area, the first sensing area being adjacent to the light-emitting element and including a plurality of first unit sensing patterns arranged in an array, each first unit sensing pattern including a plurality of first sinusoidal contour curves; and a processing unit electrically connected to the optical sensing unit. The light-emitting element emits light to the first unit patterns, the first unit patterns reflect the light and generate a plurality of first reflected light rays that are directed to the first unit sensing patterns having the first sinusoidal contour curves, the first unit sensing patterns having the first sinusoidal contour curves generating first sensing signals based on the first reflected light rays, and the processing unit converting these first sensing signals into position information.
[0007] In some embodiments, the first reflected light rays strike the first unit sensing patterns having a first sinusoidal profile curve and form a square wave light energy distribution.
[0008] In some embodiments, each first unit pattern is a long, radial pattern, and the first unit patterns are arranged in an array around a rotation axis.
[0009] In some embodiments, the outline length of each first unit sensing pattern is substantially equal to twice the outline length of each first unit pattern.
[0010] In some embodiments, a first reflected light ray is incident on a first unit sensing pattern having a first sine wave profile curve, and the first unit sensing pattern having the first sine wave profile curve generates a first sensing signal based on the first reflected light ray, and these first sensing signals generate a sine wave differential signal.
[0011] In some embodiments, each first unit sensing pattern includes a first unit sensing sub-pattern and a second unit sensing sub-pattern, which are adjacent to the first unit sensing sub-pattern.
[0012] In some embodiments, the first unit sensing subpattern includes one of a first sinusoidal profile curve, which is a quarter-wavelength portion of a sinusoidal profile, and the second unit sensing subpattern includes the other of the first sinusoidal profile curve, which is another quarter-wavelength portion of a sinusoidal profile.
[0013] In some embodiments, each first sine wave profile curve includes an amplitude, and each first unit sensing sub-pattern includes a profile width less than twice the amplitude.
[0014] In some embodiments, the code disk unit further includes N-1 second unit patterns arranged in an array, each second unit pattern including a high-reflection area and a low-reflection area; N≧2.
[0015] In some embodiments, the optical sensing unit further includes a second sensing area adjacent to the light-emitting element and includes a plurality of second unit sensing patterns arranged in an array with each other, each second unit sensing pattern including a plurality of second sine wave profile curves.
[0016] In some embodiments, the light-emitting element emits light to the second unit pattern, the second unit pattern reflects the light and generates a second reflected light that is directed to the second unit sensing pattern having a second sine wave profile curve. The second unit sensing pattern having the second sine wave profile curve generates a plurality of second sensing signals based on the second reflected light, and the processing unit converts the first sensing signals and the second sensing signals into absolute position information.
[0017] In some embodiments, a first sensing area is disposed on one side of the light-emitting element, and a second sensing area is disposed on the other side of the light-emitting element.
[0018] In some embodiments, the light-emitting element further includes a light-emitting region, the light-emitting region including a light-emitting width defined in the tangential direction of the arrangement of the first unit patterns; each first unit pattern further includes a contour length; wherein the contour length / light-emitting width is greater than 1.5.
[0019] In some embodiments, the luminous intensity distribution of the light-emitting element is a Lambertian distribution.
[0020] This disclosure provides a servo motor including an optical encoder of one of the above embodiments; and a motor body, which is shaft-connected to the optical encoder.
[0021] This disclosure provides a positioning method for an optical encoder. The optical encoder includes a code disk unit comprising N first unit patterns, where N is a positive integer; an optical sensing unit corresponding to the code disk unit and including a light-emitting element and a first sensing area, the first sensing area being adjacent to the light-emitting element and including a plurality of first unit sensing patterns arranged in an array, each first unit sensing pattern including a plurality of first sine wave contour curves; the positioning method includes the light-emitting element emitting light to the first unit patterns; the first unit patterns reflecting the light and generating first reflected light rays that are directed to the first unit sensing patterns having first sine wave contour curves; the first unit sensing patterns having first sine wave contour curves generating a plurality of first sensing signals based on the first reflected light rays; and converting these first sensing signals into position information.
[0022] In some embodiments, the first unit pattern reflecting light and generating a first reflected light beam onto the first unit sensing pattern having a first sine wave profile curve further includes the first unit pattern reflecting light and generating a first reflected light beam onto the first unit sensing pattern having a first sine wave profile curve, and forming a square wave light energy distribution on the first unit sensing pattern having the first sine wave profile curve.
[0023] In some embodiments, the generation of a first sensing signal by a first unit sensing pattern having a first sine wave profile curve based on the first reflected light rays further includes the generation of a sine wave differential signal by the first unit sensing pattern having a first sine wave profile curve based on the first reflected light rays.
[0024] In some embodiments, the emitting element emitting light to the first unit pattern further includes the emitting element emitting light to the first unit pattern, wherein the luminous intensity distribution of the light is a Lambertian distribution.
[0025] In some embodiments, the code disk unit further includes N-1 second unit patterns; the optical sensing unit further includes a second sensing area adjacent to the light-emitting element and the first sensing area, and includes a plurality of second unit sensing patterns arranged in an array with each other, each second unit sensing pattern including a plurality of second sine wave contour curves; N≧2; the positioning method further includes the light-emitting element emitting light to the second unit patterns; the second unit patterns reflecting the light and generating second reflected light rays that are directed to the second unit sensing patterns having second sine wave contour curves; the second unit sensing patterns having second sine wave contour curves generating a plurality of second sensing signals based on the second reflected light rays; and converting the first sensing signals and the second sensing signals into absolute position information.
[0026] As described above, the optical encoder, servo motor, and positioning method of the optical encoder disclosed herein utilize a first unit sensing pattern with multiple first sine wave contour curves to convert square wave light energy distribution into sine wave electrical signals, facilitating subsequent high-resolution characteristics through electronic signal fine segmentation technology. This high-resolution characteristic, combined with the accuracy of the first unit pattern on the scale code disk, achieves high-resolution and high-precision encoder performance. The arrangement of multiple first unit sensing patterns offers advantages such as good stain resistance and uniform light energy distribution. The optical sensing unit adopts an optical reflection structure, integrating the light-emitting element and the first sensing area together, resulting in a simplified structure. The optical encoder of the first embodiment of this disclosure can convert square wave light energy distribution into sine wave electrical signals when the contour length of the first unit pattern / the light-emitting width of the light-emitting area is greater than 1.5, reducing the limitations on the contour length of the first unit pattern and the light-emitting width of the light-emitting area. The contour length of the first unit pattern can be larger, providing greater assembly margin; the light-emitting width of the light-emitting area can be smaller, saving costs and internal space of the optical encoder. Furthermore, the light-emitting element exhibits a Lambertian distribution in light intensity, offering the advantage of wide-angle illumination and being readily available. The contour length of each first unit sensing pattern is substantially equal to twice the contour length of the first unit pattern itself, thereby improving signal accuracy. The contour width of the first unit sensing sub-pattern is less than twice the amplitude of the first sine wave contour curve, allowing the first, second, third, and fourth unit sensing sub-patterns to be arranged closely and alternately to save space. Multiple first sensing signals generate a sine wave differential signal, which has strong anti-interference capabilities, suppressing electromagnetic interference (EMI) and resulting in more accurate position information output. Attached Figure Description
[0027] Details of one or more embodiments of the subject matter described herein are set forth in the following drawings and description. Other features, implementations, and advantages of the subject matter of this specification will become apparent from the description, drawings, and claims, wherein:
[0028] Figure 1 is a schematic diagram of an optical encoder according to a first embodiment of the present disclosure;
[0029] Figure 2 is a schematic diagram of the encoder unit according to the first embodiment of this disclosure;
[0030] Figure 3 is a schematic diagram of the optical sensing unit of the first embodiment of this disclosure;
[0031] Figures 4A, 4B, and 4C are schematic diagrams of the first unit pattern, the first unit sensing pattern, and the light-emitting element of the first embodiment of this disclosure;
[0032] Figure 5 is a schematic diagram of a light-emitting element according to another embodiment of this disclosure;
[0033] Figure 6 is a schematic diagram of the Lambert distribution disclosed herein;
[0034] Figure 7 is a schematic diagram of the square wave light energy distribution of this disclosure;
[0035] Figures 8A, 8B and 8C are renderings of the square outline curve of this disclosure;
[0036] Figures 8D, 8E and 8F are renderings of the sine wave profile curve of this disclosure;
[0037] Figures 9A, 9B, 9C, 9D, 9E, 9F and 9G are schematic diagrams of the first unit sensing pattern of other embodiments of this disclosure;
[0038] Figure 10 is a schematic diagram of the encoder unit according to the second embodiment of this disclosure;
[0039] Figure 11 is a schematic diagram of the optical sensing unit of the second embodiment of this disclosure;
[0040] Figure 12 is a schematic diagram of the first unit sensing pattern of the second embodiment of this disclosure;
[0041] Figure 13 is a schematic diagram of a servo motor according to an embodiment of the present disclosure;
[0042] Figure 14 is a flowchart of a positioning method for an optical encoder according to an embodiment of the present disclosure;
[0043] Figure 15 is a step diagram of a positioning method for an optical encoder according to another embodiment of the present disclosure.
[0044] Figure 1: Optical encoder; 11, 11A: Code disk unit; C: Rotating shaft; T: Arrangement tangent direction; 111: First unit pattern; Rp: Long strip radial pattern; HR: High reflectivity area; LR: Low reflectivity area; Lp: Contour length; 112: Second unit pattern; 12, 12A: Optical sensing unit; 120: Light-emitting element; S1: One side; S2: The other side; 120E: Electrode; 120A: Light-emitting area; 120W: Light-emitting width; LT: Light ray; R1: First reflected light ray; R2: Second reflected light ray; 121: First sensing area; 121P: First unit sensing pattern; P1: First unit sensing sub-pattern; P2: Second unit sensing sub-pattern; P3: Third unit sensing sub-pattern; P4: Fourth unit sensing sub-pattern Ls: Contour length W: Contour width 121S: First sine wave contour curve A: Amplitude SIN: Sine contour SIN1: Quarter wavelength portion SIN2: Another quarter wavelength portion 122: Second sensing area 122P: Second unit sensing pattern 122S: Second sine wave contour curve 13: Processing unit 14: Motor body SW: Square wave light energy distribution 2: Servo motor SG1: First sensing signal SG11, SG12, SG13, SG14: Sensing sub-signal SG2: Second sensing signal SQ: Square contour curve TG: Triangular wave signal S01~S04: Positioning method steps S11~S14: Positioning method steps Detailed Implementation
[0045] The detailed description and technical content of this disclosure are illustrated below with reference to the accompanying drawings. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit this disclosure.
[0046] As used herein, terms such as “first,” “second,” “third,” and “fourth” describe various elements, components, regions, layers, and / or parts, which should not be limited by these terms. These terms are used only to distinguish one element, component, region, layer, or part from another. Unless the context clearly indicates otherwise, the use of terms such as “first,” “second,” “third,” and “fourth” herein does not imply any order or sequence.
[0047] Figure 1 is a schematic diagram of an optical encoder according to a first embodiment of the present disclosure; Figure 2 is a schematic diagram of a code disk unit according to a first embodiment of the present disclosure; Figure 3 is a schematic diagram of an optical sensing unit according to a first embodiment of the present disclosure; Figures 4A, 4B, and 4C are schematic diagrams of a first unit pattern, a first unit sensing pattern, and a light-emitting element according to a first embodiment of the present disclosure; Figure 5 is a schematic diagram of a light-emitting element according to another embodiment of the present disclosure. Referring to Figures 1, 2, 3, 4A to 4C, and 5, the optical encoder 1 of this embodiment includes a code disk unit 11, an optical sensing unit 12, and a processing unit 13.
[0048] The code disk unit 11 comprises N first unit patterns 111 arranged in an array. Each first unit pattern 111 includes a high-reflectivity area HR and a low-reflectivity area LR, where N is a positive integer. The shape of the code disk unit 11 can be, for example, a disc, an elliptical disc, a square disc, or a flat disc. The first unit pattern 111 is the basic unit forming the overall code disk pattern. For example, the first unit pattern 111 can be a square pattern with high-reflectivity areas HR and low-reflectivity areas LR arranged repeatedly along one or more straight lines or curves; the first unit pattern 111 can be a rectangular pattern with high-reflectivity areas HR and low-reflectivity areas LR arranged repeatedly along straight lines or curves; the first unit pattern 111 can be a long radial pattern Rp with high-reflectivity areas HR and low-reflectivity areas LR arranged repeatedly along straight lines or curves. The reflectivity of the high-reflectivity area HR to visible light or infrared light LT is greater than that of the low-reflectivity area LR to visible light or infrared light LT, to facilitate detection by the subsequent optical sensing unit 12. N is a positive integer such as 1, 2, 3, etc.
[0049] In some embodiments, the code disk unit 11 is shaped like a disk, and each first unit pattern 111 is a long, radial pattern Rp, arranged in an array around the rotation axis C. The long, radial patterns Rp can be, for example, rectangular or trapezoidal, arranged in an array around the rotation axis C of the disk. When the code disk unit 11 rotates relative to the rotation axis C, the change in light energy of the long, radial patterns Rp due to the rotation can be observed from a fixed position on the first unit patterns 111.
[0050] An optical sensing unit 12, corresponding to the code disk unit 11, includes a light-emitting element 120 and a first sensing area 121. The optical sensing unit 12 can be disposed on, for example, the first unit pattern 111 and can receive the light energy changes generated by the rotation of the elongated radial pattern Rp. The light-emitting element 120 and the first sensing area 121 are integrated together, thereby simplifying the structure. The light-emitting element 120 may include, for example, a light-emitting unit (not shown), an electrode 120E, and a light-emitting area 120A. The light-emitting unit may be, for example, a light-emitting diode (LED), a vertical-cavity surface-emitting laser (VCSEL), or a laser diode (LD). The electrode 120E may be made of conductive materials such as copper, silver, aluminum, or gold. When the electrode 120E is connected to an external power source, it can provide electrical energy to the light-emitting unit to generate light LT. The light-emitting area 120A allows the light LT generated by the light-emitting unit to pass through. The shape of the light-emitting area 120A can be, for example, a circle, an ellipse, a square, a rectangle, or a rectangle with rounded corners.
[0051] Figure 6 is a schematic diagram of the Lambertian distribution of this disclosure; please refer to Figures 5 and 6. In some embodiments, the luminous intensity distribution of the light-emitting element 120 is a Lambertian distribution. The spatial distribution of luminous intensity in the Lambertian distribution conforms to the cosine law; the radiation intensity at different angles varies according to the cosine formula, with the intensity decreasing as the angle increases. Mathematically, this is expressed as I(θ) = I0cosθ, where I(θ) is the luminous intensity value at θ, and I0 is the luminous intensity value at 0°.
[0052] Please refer to Figures 1, 3, and 4A-4C. A first sensing region 121 is disposed adjacent to the light-emitting element 120 and includes a plurality of first unit sensing patterns 121P arranged in an array. Each first unit sensing pattern 121P includes a plurality of first sine wave contour curves 121S. The first unit sensing patterns 121P may, for example, be disposed on the same substrate as the light-emitting element 120. The first unit sensing pattern 121P is the basic unit forming the overall sensing pattern. The first unit sensing pattern 121P may, for example, be a pattern with a sine contour SIN or a pattern with a cosine contour arranged in a repeating pattern of one or more straight lines / curves.
[0053] In some embodiments, the outline length Ls of each first unit sensing pattern 121P is substantially equal to twice the outline length Lp of each first unit pattern 111. The outline length Ls of the first unit sensing pattern 121P can, for example, be the length of one of the side lengths of the first unit sensing pattern 121P, defined in the tangential direction T of the arrangement of the first unit patterns 111. The outline length Ls of the first unit sensing pattern 121P is approximately twice the outline length Lp of the first unit pattern 111.
[0054] In some embodiments, each first unit sensing pattern 121P includes a first unit sensing sub-pattern P1 and a second unit sensing sub-pattern P2, adjacent to the first unit sensing sub-pattern P1. The shape of the first unit sensing pattern 121P is similar to the shape of the second unit sensing sub-pattern P2. In some embodiments, the first unit sensing pattern 121P and the second unit sensing sub-pattern P2 can sense and output signals individually.
[0055] In some embodiments, each first sine wave profile curve 121S includes an amplitude A, and each first unit sensing sub-pattern P1 includes a profile width W, which is less than twice the amplitude A. The direction of the profile width W and the direction of the amplitude A are, for example, perpendicular to the direction of the profile length Ls of the first unit sensing sub-pattern 121P. The first unit sensing sub-patterns P1 are arranged in a closely staggered manner, so that the first unit sensing sub-pattern P1, the second unit sensing sub-pattern P2, the third unit sensing sub-pattern P3, and the fourth unit sensing sub-pattern P4 can be arranged in a closely staggered manner to save space.
[0056] In some embodiments, the first unit sensing sub-pattern P1 includes one of the first sinusoidal contour curves 121S, which is a quarter-wavelength portion SIN1 of the sinusoidal contour SIN. The second unit sensing sub-pattern P2 includes the other of the first sinusoidal contour curves 121S, which is another quarter-wavelength portion SIN2 of the sinusoidal contour SIN. The first unit sensing sub-pattern P1 may include, for example, phase angle portions of the sinusoidal contour SIN from 0 to 90 degrees, 90 to 180 degrees, 180 to 270 degrees, and 270 to 360 degrees, but this is not limiting. The second unit sensing sub-pattern P2 may include, for example, phase angle portions of the sinusoidal contour SIN from 0 to 90 degrees, 90 to 180 degrees, 180 to 270 degrees, and 270 to 360 degrees, to convert changes in light energy into sinusoidal signals.
[0057] Please refer to Figure 1. The processing unit 13 is electrically connected to the optical sensing unit 12. The processing unit 13 may be, for example, a digital signal processor (DSP), a central processing unit (CPU), a microcontroller unit (MCU), a field programmable gate array (FPGA), or a system on chip (SoC), etc., but is not limited thereto.
[0058] Figures 8A, 8B, and 8C are renderings of the square contour curve of this disclosure; Figures 8D, 8E, and 8F are renderings of the sine wave contour curve of this disclosure. Please refer to Figures 1, 4A-4C, and 8A-8F. The light-emitting element 120 emits light LT to the first unit pattern 111. The first unit pattern 111 reflects the light LT and generates a first reflected light ray R1, which is directed to the first unit pattern 111 having a first sine wave contour curve 121S. The first unit pattern 111 having the first sine wave contour curve 121S generates a plurality of first sensing signals SG1 based on the first reflected light ray R1. The processing unit 13 converts these first sensing signals SG1 into position information. The light-emitting element 120 emits light LT to the first unit pattern 111. Since the first unit pattern 111 includes a high reflectivity area HR and a low reflectivity area LR, when the code disk unit 11 rotates, the first unit pattern 111 with a first sine wave profile curve 121S can generate a first sensing signal SG1 according to the change of light energy. The processing unit 13 can, for example, convert the first sensing signal SG1 into incremental position information such as angular displacement.
[0059] Figure 7 is a schematic diagram of the square wave light energy distribution of this disclosure. Please refer to Figures 1, 2, 3, 4A-4C, 7, and 8A-8F. In some embodiments, the light-emitting region 120A includes a light-emitting width 120W defined in the tangential direction T of the arrangement of the first unit pattern 111; each first unit pattern 111 also includes a contour length Lp; wherein the contour length Lp / light-emitting width 120W is greater than 1.5. The light-emitting width 120W of the light-emitting region 120A can be, for example, one of the lengths of the outer diameter of the light-emitting region 120A, and the contour length Lp of the first unit pattern 111 can be, for example, one of the lengths of the side of the first unit pattern 111. The direction of the light-emitting width 120W of the light-emitting region 120A and the direction of the contour length Lp of the first unit pattern 111 are defined in the tangential direction T of the arrangement of the first unit patterns 111. When the ratio of the contour length Lp to the emission width 120W is greater than 1.5, the first reflected ray R1 can form a square wave light energy distribution SW by hitting the first unit sensing pattern 121P with the first sinusoidal contour curve 121S. The square wave light energy distribution SW may have imperfections such as tilt and jitter.
[0060] In some embodiments, the first unit pattern 111 is a long, radial pattern Rp. The light-emitting element 120 emits light LT onto the long, radial pattern Rp, causing the first reflected light ray R1 to strike the first unit sensing pattern 121P with a first sine wave profile curve 121S, forming a square wave light energy distribution SW. However, this is not a limitation. The first unit sensing pattern 121P with the first sine wave profile curve 121S can convert the square wave light energy distribution SW into a sine wave electrical signal, which facilitates the subsequent achievement of high-resolution characteristics through electronic signal fine segmentation technology. For example, the first unit pattern 111 on the code disk unit 11 can have a 6-bit period scale pattern to achieve 6-bit accuracy. The electronic signal fine segmentation technology further divides the sine wave signal corresponding to each period of the first unit pattern 111 into 14-bit equal parts to further achieve a final total resolution of 20 bits.
[0061] Additionally, it is worth noting that if the first unit sensing pattern 121P does not include multiple first sine wave contour curves 121S, but instead includes multiple square contour curves SQ, then the first reflected light ray R1 will be directed to the square contour curve SQ and form a triangular wave signal TG.
[0062] Figures 9A, 9B, 9C, 9D, 9E, 9F, and 9G are schematic diagrams of the first unit sensing pattern in other embodiments of this disclosure. Please refer to Figures 1, 3, 4A-4C, 8A-8F, and 9A-9G. In some embodiments, a first reflected light ray R1 is incident on a first unit sensing pattern 121P having a first sine wave profile curve 121S. The first unit sensing pattern 121P with the first sine wave profile curve 121S generates a plurality of first sensing signals SG1 based on the first reflected light ray R1. These first sensing signals SG1 generate sine wave differential signals. The sine wave differential signals are a set of two signals with the same amplitude A and opposite phases. The plurality of first sensing signals SG1 may be, for example, sensing sub-signals SG11 generated by a first unit sensing sub-pattern P1, SG12 generated by a second unit sensing sub-pattern P2, SG13 generated by a third unit sensing sub-pattern P3, and SG14 generated by a fourth unit sensing sub-pattern P4. Sensing sub-signal SG12 can be configured to have a 90-degree phase angle difference from sensing sub-signal SG11; sensing sub-signal SG13 can be configured to have a 180-degree phase angle difference from sensing sub-signal SG11; and sensing sub-signal SG14 can be configured to have a 270-degree phase angle difference from sensing sub-signal SG11. Sensing sub-signal SG11 and sensing sub-signal SG13 can form a differential signal; sensing sub-signal SG12 and sensing sub-signal SG14 can form a differential signal.
[0063] The relative positions of the first unit sensing sub-pattern P1, the second unit sensing sub-pattern P2, the third unit sensing sub-pattern P3, and the fourth unit sensing sub-pattern P4 can vary in several ways. As shown in Figures 9A, 9C, 9F, and 9G, these sub-patterns are arranged in opposite directions. As shown in Figures 9B and 9D, they are arranged in the same direction. As shown in Figure 9E, they are arranged in an alternating pattern. As shown in Figure 9F, they are arranged in an alternating pattern. As shown in Figure 9G, the first unit sensing sub-pattern P1, the second unit sensing sub-pattern P2, the third unit sensing sub-pattern P3, and the fourth unit sensing sub-pattern P4 are closely arranged.
[0064] As described above, the first unit sensing pattern 121P of the optical encoder 1 of the first embodiment of this disclosure, which has multiple first sine wave contour curves 121S, can convert the square wave light energy distribution SW into a sine wave electrical signal, thereby facilitating the subsequent realization of high-resolution characteristics through electronic signal fine segmentation technology. This high-resolution characteristic, combined with the accuracy of the first unit pattern 111 of the scale code disk, can achieve high-resolution and high-precision encoder performance. The arrangement of multiple first unit sensing patterns 121P has the advantages of good stain resistance and uniform light energy distribution. The optical sensing unit 12 adopts an optical reflection structure, and the light-emitting element 120 is integrated with the first sensing area 121, resulting in a simplified structure. The optical encoder 1 of the first embodiment of this disclosure can convert the square wave light energy distribution SW into a sine wave electrical signal when the contour length Lp of the first unit pattern 111 / the light-emitting width 120W of the light-emitting area 120A is greater than 1.5, thereby reducing the limitations on the contour length Lp of the first unit pattern 111 and the light-emitting width 120W of the light-emitting area 120A. The outline length Lp of the first unit pattern 111 can be relatively large, allowing for greater assembly margin in the mechanism; the light-emitting width 120W of the light-emitting area 120A can be relatively small, saving cost and internal space of the optical encoder 1. Furthermore, the light intensity distribution of the light-emitting element 120 is a Lambertian distribution, which offers the advantage of wide-angle illumination and is readily available. The outline length Ls of each first unit sensing pattern 121P is substantially equal to twice the outline length Lp of each first unit pattern 111, thereby improving signal accuracy. The outline width W of the first unit sensing sub-pattern P1 is less than twice the amplitude A of the first sine wave profile curve 121S, allowing the first unit sensing sub-pattern P1, the second unit sensing sub-pattern P2, the third unit sensing sub-pattern P3, and the fourth unit sensing sub-pattern P4 to be arranged closely and alternately to save space. Multiple first sensing signals SG1 generate a sine wave differential signal, which has strong anti-interference capabilities, suppressing electromagnetic interference (EMI) and making the position information output more accurate.
[0065] Figure 10 is a schematic diagram of the code disk unit of the second embodiment of this disclosure, Figure 11 is a schematic diagram of the optical sensing unit of the second embodiment of this disclosure, and Figure 12 is a schematic diagram of the first unit sensing pattern of the second embodiment of this disclosure. Please refer to Figures 1, 4A-4C, 8A-8F, 10, 11, and 12. The code disk unit 11A, optical sensing unit 12A, and processing unit 13 (as shown in Figure 1) of the second embodiment of this disclosure are similar to those of the first embodiment. The main difference is that the code disk unit 11A also includes a second unit pattern 112, and the optical sensing unit 12A also includes a second sensing area 122. The overall operation and signal processing methods of the processing unit 13 are different, as described below. It is worth mentioning that the optical encoder 1 (as shown in Figure 1) can also use the code disk unit 11A and the optical sensing unit 12A, which will not be described in detail here.
[0066] The code disk unit 11A also includes N-1 second unit patterns 112 arranged in an array, each second unit pattern 112 including a high-reflection area HR and a low-reflection area LR; N≧2. The structure of the second unit pattern 112 is similar to that of the first unit pattern 111, and the second unit pattern 112 can be adjacent to the first unit pattern 111. The code disk unit 11A can, for example, have 64 first unit patterns 111 and 63 second unit patterns 112. The outline width W of the first unit pattern 111 and the second unit pattern 112 has a slight difference, so absolute position information and higher accuracy can be obtained through a principle similar to a vernier caliper. The second unit pattern 112 can also be a long radial pattern Rp, arranged in an array around the rotation axis C.
[0067] The optical sensing unit 12A further includes a second sensing region 122, which is adjacent to the light-emitting element 120 and includes a plurality of second unit sensing patterns 122P arranged in an array. Each second unit sensing pattern 122P includes a plurality of second sinusoidal contour curves 122S. The structure of the second sensing region 122 is similar to that of the first sensing region 121. The first sensing region 121 and the second sensing region 122 may, for example, be disposed on the same substrate as the light-emitting element 120. The contour length Ls of the second unit sensing pattern 122P may be substantially equal to twice the contour length Lp of each second unit pattern 112. The contour width W of the second unit sensing pattern 122P may be less than twice the amplitude A of the second sinusoidal contour curve 122S. The structure of the second unit sensing pattern 122P is similar to that of the first unit sensing pattern 121P. The second unit sensing pattern 122P may have a first unit sensing sub-pattern P1, a second unit sensing sub-pattern P2, a third unit sensing sub-pattern P3, and a fourth unit sensing sub-pattern P4. The first unit sensing sub-pattern P1 of the second unit sensing pattern 122P may include one of the first sine wave profile curves 121S, one of which is a quarter-wavelength portion SIN1 of the sinusoidal profile SIN. The second unit sensing sub-pattern P2 may include the other of the first sine wave profile curves 121S, the other of which is another quarter-wavelength portion SIN2 of the sinusoidal profile SIN.
[0068] It is worth mentioning that the first unit sensing pattern 121P and the second unit sensing pattern 122P in this embodiment can be similar to the patterns in Figure 4B and Figures 9A to 9G, or they can be similar to the pattern in Figure 12, but this is not limiting.
[0069] The light-emitting element 120 emits light LT to the second unit pattern 112. The second unit pattern 112 reflects the light LT and generates a second reflected light ray R2, which is directed to the second unit sensing pattern 122P having a second sine wave profile curve 122S. The second unit sensing pattern 122P with the second sine wave profile curve 122S generates multiple second sensing signals SG2 based on the second reflected light ray R2. The processing unit 13 converts these first sensing signals SG1 and the second sensing signals SG2 into absolute position information. The light-emitting element 120 emits light LT to the first unit pattern 111 and the second unit pattern 112. Since the first unit pattern 111 and the second unit pattern 112 include a high-reflection area HR and a low-reflection area LR, when the code disk unit 11A rotates, the first unit sensing pattern 121P with the first sine wave profile curve 121S can generate a first sensing signal SG1 based on the change in light energy, and the second unit sensing pattern 122P with the second sine wave profile curve 122S can generate a second sensing signal SG2 based on the change in light energy. The processing unit 13 can perform calculations similar to those using a vernier caliper based on the first sensing signal SG1 and the second sensing signal SG2 to obtain absolute position information such as angles. It is worth noting that while Figure 8E shows that both the first sine wave profile curve 121S and the second sine wave profile curve 122S are sine wave profile curves, this does not mean that the waveforms of the first sine wave profile curve 121S and the second sine wave profile curve 122S are identical. Similarly, Figure 8F shows that both the first sensing signal SG1 and the second sensing signal SG2 are sine wave signals, but this does not mean that the waveforms of the first sensing signal SG1 and the second sensing signal SG2 are identical.
[0070] In some embodiments, the second unit pattern 112 is a long, radial pattern Rp. The light-emitting element 120 emits light LT onto the long, radial pattern Rp, and the second reflected light R2 strikes the second unit sensing pattern 122P, which has a second sinusoidal contour curve 122S, to form a square wave light energy distribution SW. However, this is not a limitation. The second unit sensing pattern 122P with the second sinusoidal contour curve 122S can convert the square wave light energy distribution SW into a sinusoidal electrical signal, which is beneficial for achieving high-resolution characteristics through subsequent electronic signal fine segmentation technology. Thus, the processing unit 13 can perform calculations similar to the vernier caliper principle based on the first sensing signal SG1 and the second sensing signal SG2 to obtain more accurate absolute position information.
[0071] In some embodiments, the second reflected light ray R2 is directed to the second unit sensing pattern 122P having the second sine wave profile curve 122S. The second unit sensing pattern 122P having the second sine wave profile curve 122S generates a second sensing signal SG2 based on the second reflected light ray R2. Multiple second sensing signals SG2 generate sine wave differential signals.
[0072] In some embodiments, a first sensing area 121 is disposed on one side S1 of the light-emitting element 120, and a second sensing area 122 is disposed on the other side S2 of the light-emitting element 120. For example, the first sensing area 121 may be disposed on the outer side of the code disk unit 11A, and the second sensing area 122 may be disposed on the inner side of the code disk unit 11A; or the first sensing area 121 may be disposed on the inner side of the code disk unit 11A, and the second sensing area 122 may be disposed on the outer side of the code disk unit 11A.
[0073] As described above, the optical encoder 1 of the second embodiment of this disclosure, in addition to having the effects of the first embodiment, also has the following effects. The first unit pattern 111, the second unit pattern 112, the first unit sensing pattern 121P, and the second unit sensing pattern 122P of the second embodiment of this disclosure can obtain absolute position information such as angles. The first unit sensing pattern 121P with a first sine wave profile curve 121S and the second unit sensing pattern 122P with a second sine wave profile curve 122S of this disclosure can obtain more accurate absolute position information such as angles. The first sensing area 121 is disposed on one side S1 of the light-emitting element 120, and the second sensing area 122 is disposed on the other side S2 of the light-emitting element 120, which simplifies the structure and reduces interference from light LT.
[0074] Figure 13 is a schematic diagram of a servo motor according to an embodiment of the present disclosure. Please refer to Figures 1 and 13. The servo motor 2 of this embodiment includes an optical encoder 1 having the encoder units 11, 11A and optical sensing units 12, 12A as in the first embodiment or the second embodiment, and a motor body 14.
[0075] When the motor body 14 is shaft-connected to the optical encoder 1 of the first embodiment, the rotation of the motor body 14 can drive the code disk unit 11 of the optical encoder 1, and the optical encoder 1 can obtain incremental position information such as angular displacement. As a result, the servo motor 2 can achieve a high-resolution and high-precision control effect.
[0076] When the motor body 14 is shaft-connected to the optical encoder 1 of the second embodiment, the rotation of the motor body 14 can drive the code disk unit 11A of the optical encoder 1 (as shown in FIG11), and the optical encoder 1 can obtain absolute position information such as angle. Thus, the servo motor 2 can achieve the effect of high-resolution, high-precision control and absolute position control.
[0077] Figure 14 is a step diagram of a positioning method for an optical encoder according to an embodiment of the present disclosure. Please refer to Figures 1, 3, and 14. The positioning method of the optical encoder in this embodiment works in conjunction with an optical encoder, which includes a code disk unit 11 comprising N first unit patterns 111, where N is a positive integer; an optical sensing unit 12 is correspondingly disposed with the code disk unit 11 and includes a light-emitting element 120 and a first sensing area 121. The first sensing area 121 is adjacent to the light-emitting element 120 and includes multiple first unit sensing patterns 121P arranged in an array, each first unit sensing pattern 121P including multiple first sine wave contour curves 121S. The positioning method includes steps S01 to S04. Step S01 is that the light-emitting element emits light to the first unit pattern. Step S02 is that the first unit pattern reflects light and generates first reflected light that is directed to the first unit sensing pattern having the first sine wave contour curve. Step S03 is that the first unit sensing pattern having the first sine wave contour curve generates multiple first sensing signals based on the first reflected light. Step S04 involves converting these first sensing signals into position information. The positioning method of the optical encoder in this embodiment can also be used in conjunction with the optical encoder 1 of the first embodiment or the optical encoder 1 of the second embodiment. The detailed positioning method has been described in detail in the above embodiments and will not be repeated here.
[0078] Figure 15 is a step diagram of the positioning method of an optical encoder according to another embodiment of the present disclosure. Please refer to Figures 1, 3 and 15. The positioning method of the optical encoder in this embodiment is in conjunction with an optical encoder, which includes a code disk unit 11 including N first unit patterns 111, where N is a positive integer; an optical sensing unit 12 is correspondingly disposed with the code disk unit 11 and includes a light-emitting element 120 and a first sensing area 121. The first sensing area 121 is adjacent to the light-emitting element 120 and includes a plurality of first unit sensing patterns 121P arranged in an array with each other. Each first unit sensing pattern 121P includes a plurality of first sine wave contour curves 121S. The positioning method includes steps S11 to S14. Step S11 is that the light-emitting element emits light to the first unit pattern and the second unit pattern, and the light intensity distribution is a Lambertian distribution. Step S12: The first unit pattern reflects light and generates a first reflected light ray, which is directed to the first unit sensing pattern having a first sine wave contour curve, forming a square wave light energy distribution on the first unit sensing pattern having the first sine wave contour curve; the second unit pattern reflects light and generates a second reflected light ray, which is directed to the second unit sensing pattern having a second sine wave contour curve, forming a square wave light energy distribution on the second unit sensing pattern having the second sine wave contour curve. Step S13: The first unit sensing pattern having the first sine wave contour curve generates a first sensing signal based on the first reflected light ray, the first sensing signal being a sine wave differential signal; the second unit sensing pattern having the second sine wave contour curve generates a second sensing signal based on the second reflected light ray, the second sensing signal being a sine wave differential signal. Step S14: These first sensing signals and these second sensing signals are converted into absolute position information. The positioning method of the optical encoder in this embodiment can also be used in conjunction with the optical encoder 1 of the first embodiment or the optical encoder 1 of the second embodiment. The detailed positioning method has been described in detail in the above embodiments and will not be repeated here.
[0079] In summary, the optical encoder, servo motor, and positioning method of the optical encoder disclosed herein utilize a first unit sensing pattern with multiple first sine wave contour curves to convert square wave light energy distribution into sine wave electrical signals, facilitating subsequent high-resolution characteristics through electronic signal fine segmentation technology. This high-resolution characteristic, combined with the accuracy of the first unit pattern on the scale code disk, achieves high-resolution and high-precision encoder performance. The arrangement of multiple first unit sensing patterns offers advantages such as good stain resistance and uniform light energy distribution. The optical sensing unit adopts an optical reflection structure, integrating the light-emitting element and the first sensing area together, resulting in a simplified structure. The optical encoder of the first embodiment of this disclosure can convert square wave light energy distribution into sine wave electrical signals when the contour length of the first unit pattern / the light-emitting width of the light-emitting area is greater than 1.5, reducing the limitations on the contour length of the first unit pattern and the light-emitting width of the light-emitting area. The contour length of the first unit pattern can be larger, providing greater assembly margin; the light-emitting width of the light-emitting area can be smaller, saving costs and internal space of the optical encoder. Furthermore, the light-emitting element exhibits a Lambertian distribution in light intensity, offering the advantage of wide-angle illumination and being readily available. The contour length of each first unit sensing pattern is substantially equal to twice the contour length of the first unit pattern itself, thereby improving signal accuracy. The contour width of the first unit sensing sub-pattern is less than twice the amplitude of the first sine wave contour curve, allowing the first, second, third, and fourth unit sensing sub-patterns to be arranged closely and alternately to save space. Multiple first sensing signals generate a sine wave differential signal, which has strong anti-interference capabilities, suppressing electromagnetic interference (EMI) and resulting in more accurate position information output.
[0080] The first unit pattern, second unit pattern, first unit sensing pattern, and second unit sensing pattern of the optical encoder, servo motor, and positioning method of the optical encoder disclosed herein can obtain absolute position information. The first unit sensing pattern having a first sine wave profile curve and the second unit sensing pattern having a second sine wave profile curve of the present disclosure can obtain more accurate absolute position information. The first sensing area being disposed on one side of the light-emitting element and the second sensing area being disposed on the other side of the light-emitting element simplifies the structure and reduces interference from light LT.
[0081] Unless otherwise defined, the terms "substantially" and "approximately" are used to describe and narrate small changes. When combined with an event or situation, the term may include the exact moment the event or situation occurred, or an approximate point in time. For example, when combined with a numerical value, the term may include a range of variation less than or equal to ±10% of the value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%.
[0082] The foregoing has outlined components of several embodiments to enable those skilled in the art to better understand the concepts of the embodiments of this disclosure. Those skilled in the art should understand that other processes and structures can be designed or modified based on the embodiments of this disclosure to achieve the same purpose and / or benefits as the embodiments described herein. Those skilled in the art should also understand that these equivalent structures do not depart from the spirit and scope of this disclosure, and various changes, substitutions, and other options can be made herein without departing from the spirit and scope of this disclosure. Therefore, the scope of protection of this disclosure is defined by the claims.
Claims
1. An optical encoder, comprising: The code disk unit includes N first unit patterns arranged in an array, each first unit pattern including a high reflective area and a low reflective area, where N is a positive integer; An optical sensing unit is configured corresponding to the code disk unit and includes a light-emitting element and a first sensing area. The first sensing area is adjacent to the light-emitting element and includes a plurality of first unit sensing patterns arranged in an array with each other. Each first unit sensing pattern includes a plurality of first sine wave contour curves. and The processing unit is electrically connected to the optical sensing unit; The light-emitting element emits light to the N first unit patterns, the N first unit patterns reflect the light and generate first reflected light that is directed to the plurality of first unit sensing patterns having the plurality of first sine wave contour curves, the plurality of first unit sensing patterns having the plurality of first sine wave contour curves generate a plurality of first sensing signals based on the first reflected light, and the processing unit converts the plurality of first sensing signals into position information.
2. The optical encoder according to claim 1, wherein the first reflected light is incident on the plurality of first unit sensing patterns having the plurality of first sine wave profile curves and forms a square wave light energy distribution.
3. The optical encoder according to claim 2, wherein each of the first unit patterns is a long strip radial pattern, and the N first unit patterns are arranged in an array around the rotating shaft.
4. The optical encoder of claim 3, wherein the outline length of each of the first unit sensing patterns is substantially equal to twice the outline length of each of the first unit patterns.
5. The optical encoder according to claim 1, wherein the first reflected light is incident on the plurality of first unit sensing patterns having the plurality of first sine wave profile curves, the plurality of first unit sensing patterns having the plurality of first sine wave profile curves generate the plurality of first sensing signals according to the first reflected light, and the plurality of first sensing signals generate sine wave differential signals.
6. The optical encoder of claim 1, wherein each of the first unit sensing patterns comprises: The first unit senses the sub-pattern, and The second unit sensing sub-pattern is disposed adjacent to the first unit sensing sub-pattern.
7. The optical encoder of claim 6, wherein the first unit sensing sub-pattern includes one of the plurality of first sine wave profile curves, the one of the plurality of first sine wave profile curves being a quarter-wavelength portion of a sine profile, and the second unit sensing sub-pattern includes another of the plurality of first sine wave profile curves, the other of the plurality of first sine wave profile curves being another quarter-wavelength portion of the sine profile.
8. The optical encoder of claim 6, wherein each of the first sine wave profile curves includes an amplitude, and each of the first unit sensing subpatterns includes a profile width, the profile width being less than twice the amplitude.
9. The optical encoder according to claim 1, wherein the code disk unit further comprises: N-1 second unit patterns are arranged in an array with each other, and each second unit pattern includes a high reflectance area and a low reflectance area; Where N≧2.
10. The optical encoder of claim 9, wherein the optical sensing unit further comprises: The second sensing area is adjacent to the light-emitting element and includes a plurality of second unit sensing patterns arranged in an array with each other, each second unit sensing pattern including a plurality of second sine wave contour curves.
11. The optical encoder of claim 10, wherein the light-emitting element emits light to the N-1 second unit patterns, the N-1 second unit patterns reflect the light and generate second reflected light that is directed to the plurality of second unit sensing patterns having the plurality of second sine wave contour curves, the plurality of second unit sensing patterns having the plurality of second sine wave contour curves generate a plurality of second sensing signals based on the second reflected light, and the processing unit converts the plurality of first sensing signals and the plurality of second sensing signals into absolute position information.
12. The optical encoder according to claim 11, wherein the first sensing area is disposed on one side of the light-emitting element, and the second sensing area is disposed on the other side of the light-emitting element.
13. The optical encoder according to claim 1, wherein the light-emitting element further comprises: The light-emitting area includes a light-emitting width defined in the tangential direction of the arrangement of the first unit patterns; each of the first unit patterns also includes a contour length; wherein the contour length / light-emitting width is greater than 1.
5.
14. The optical encoder according to claim 13, wherein the light-emitting element has a Lambertian distribution in terms of light intensity.
15. A servo motor, comprising: An optical encoder as claimed in any one of claims 1 to 14; and The motor body is shaft-connected to the optical encoder.
16. A positioning method for an optical encoder, the optical encoder comprising: The code disk unit consists of N first unit patterns, where N is a positive integer; An optical sensing unit is configured correspondingly to the code disk unit and includes a light-emitting element and a first sensing area. The first sensing area is adjacent to the light-emitting element and includes a plurality of first unit sensing patterns arranged in an array with each other. Each first unit sensing pattern includes a plurality of first sine wave contour curves. The positioning method includes: The light-emitting element emits light onto the N first unit patterns; The N first unit patterns reflect the light and generate first reflected light rays that are directed onto the plurality of first unit sensing patterns having the plurality of first sine wave profile curves; The plurality of first unit sensing patterns having the plurality of first sinusoidal contour curves generate a plurality of first sensing signals based on the first reflected light; and The plurality of first sensing signals are converted into location information.
17. The positioning method according to claim 16, wherein the N first unit patterns reflect the light and generate the first reflected light rays that are directed onto the plurality of first unit sensing patterns having the plurality of first sinusoidal contour curves, further comprising: The N first unit patterns reflect the light and generate the first reflected light, which is directed onto the plurality of first unit sensing patterns having the plurality of first sine wave contour curves, and forms a square wave light energy distribution on the plurality of first unit sensing patterns having the plurality of first sine wave contour curves.
18. The positioning method according to claim 17, wherein the plurality of first unit sensing patterns having the plurality of first sinusoidal contour curves generate the plurality of first sensing signals based on the first reflected light rays, further comprising: The plurality of first unit sensing patterns having the plurality of first sine wave profile curves generate sine wave differential signals based on the first reflected light.
19. The positioning method according to claim 16, wherein the light-emitting element emits the light to the N first unit patterns, further comprising: The light-emitting element emits light to the N first unit patterns, and the light intensity distribution is a Lambertian distribution.
20. The positioning method according to claim 16, wherein the code disk unit further comprises N-1 second unit patterns; the optical sensing unit further comprises a second sensing area, the second sensing area being adjacent to the light-emitting element and the first sensing area, and comprising a plurality of second unit sensing patterns arranged in an array with each other, each second unit sensing pattern comprising a plurality of second sine wave contour curves; wherein, N≧2; the positioning method further includes: The light-emitting element emits the light to the N-1 second unit patterns; The N-1 second unit patterns reflect the light and generate second reflected light rays that are directed onto the plurality of second unit sensing patterns having the plurality of second sine wave profile curves; The plurality of second unit sensing patterns having the plurality of second sinusoidal contour curves generate a plurality of second sensing signals based on the second reflected light; and The plurality of first sensing signals and the plurality of second sensing signals are converted into absolute position information.