Optical sensor assembly and encoder

Abstract

To provide an optical sensor assembly.SOLUTION: An optical sensor assembly includes a scale, a sensor, and a light source. The scale includes a first pattern area comprising first patterns periodically arranged in a first direction, and a second pattern area comprising second patterns periodically arranged in the first direction and a second direction. The sensor is configured to move relative to the scale in the first direction and includes a first sensing area configured to sense a change of the first pattern area in the first direction, a second sensing area configured to sense a change of the second pattern area in the first direction, and a third sensing area configured to sense a change of the second pattern area in the second direction. The light source is configured to emit light toward the scale.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to optical sensor assemblies and encoders. [Background technology]

[0002] With the advancement of science and technology, encoder technology has been widely applied to the control field of precision equipment, such as motor rotation speed measurement and position detection. For example, absolute encoders can be used to detect the rotation speed, rotation direction, and rotation position of a motor.

[0003] In well-known technology, an optical encoder uses a gray code or an M-sequence code (M code) to obtain absolute position information, and its main architecture includes a light projector, a light receiver, a code disk, and a processing circuit. The light projector and the light receiver of a reflective optical encoder are provided on the same side of the code disk, and a required signal output is obtained by appropriately designing the pattern on the code disk. Summary of the Invention [Problem to be solved by the invention]

[0004] However, known encoder architectures and encoding methods are highly sensitive to position deviations, requiring extremely precise assembly and alignment of the encoder. As the demand for encoder precision increases, the sensing area of ​​the corresponding receiver also shrinks significantly, meaning that external environmental contamination such as oil stains, dirt, and particles can seriously affect the detection of absolute position signals.

[0005] Therefore, how to develop a non-traditional optical sensor assembly and an encoder using the same to overcome the problems and shortcomings in the known technology, realize high-precision absolute position detection, have higher resistance to environmental contamination, and improve the stability of the encoder, is actually an important issue in the current technical field. [Means for solving the problem]

[0006] In view of this, one object of the present disclosure is to propose an optical sensor assembly and an encoder using the same that can solve the above problems.

[0007] To achieve this object, according to one embodiment of the present disclosure, an optical sensor assembly includes a scale, a sensor, and a light source. The scale includes a first pattern area including a plurality of first patterns periodically arranged in a first direction, and a second pattern area including a plurality of second patterns periodically arranged in the first and second directions. The sensor includes a first detector arranged to detect changes in the first pattern area in the first direction, a second detector arranged to detect changes in the second pattern area in the first direction, and a third detector arranged to detect changes in the second pattern area in the second direction, and is arranged to move relative to the scale in the first direction. The light source is arranged to emit light toward the scale.

[0008] In one or more embodiments of the present disclosure, the second patterns aligned along the first direction are gradually offset in the second direction.

[0009] In one or more embodiments of the present disclosure, the second patterns are arranged in rows, the rows having a pitch in a first direction, the second patterns in each row having a different pitch in a second direction, the rows progressively offset by one different pitch in the second direction after a distance of N times the pitch along the first direction, and N being an integer greater than 2.

[0010] In one or more embodiments of the present disclosure, after the sensor moves a distance of N times the pitch in the first direction relative to the scale, the second sensing unit generates N periodic signals and the third sensing unit generates one periodic signal.

[0011] In one or more embodiments of the present disclosure, the light receiving elements of the first detector, the second detector, and the third detector are arranged out of phase with each other.

[0012] To achieve the above object, according to one embodiment of the present disclosure, an encoder includes an optical sensor assembly and a signal processing unit. The optical sensor assembly includes a scale and a sensor, wherein the scale includes a first pattern area including a plurality of first patterns periodically arranged in a first direction and a second pattern area including a plurality of second patterns periodically arranged in the first and second directions, and the sensor includes a first detector disposed to detect a change in the first pattern area in the first direction and correspondingly generate a first detected position signal, a second detector disposed to detect a change in the second pattern area in the first direction and correspondingly generate a second detected position signal, and a third detector disposed to detect a change in the second pattern area in the second direction and correspondingly generate a third detected position signal, and is disposed to move in the first direction relative to the scale. The signal processing unit is arranged and connected to the sensor to calculate first detected position information, second detected position information, and third detected position information from the first detected position signal, second detected position signal, and third detected position signal, respectively, calculate first combined position information from the first detected position information and the second detected position information, and calculate second combined position information from the third detected position information and the first combined position information.

[0013] In one or more embodiments of the present disclosure, the second patterns aligned along the first direction are gradually offset in the second direction.

[0014] In one or more embodiments of the present disclosure, the second patterns are arranged in rows, the rows having a pitch in a first direction, the second patterns in each row having a different pitch in a second direction, the rows progressively offset by one different pitch in the second direction after a distance of N times the pitch along the first direction, and N being an integer greater than 2.

[0015] In one or more embodiments of the present disclosure, after the sensor moves a distance of N times the pitch in the first direction relative to the scale, the second sensing unit generates N periodic signals and the third sensing unit generates one periodic signal.

[0016] In one or more embodiments of the present disclosure, the light receiving elements of the first detector, the second detector, and the third detector are arranged out of phase with each other.

[0017] In one or more embodiments of the present disclosure, the signal processing unit is configured to calculate first composite position information according to the first detected position information and the second detected position information based on a Vernier method.

[0018] In one or more embodiments of the present disclosure, the first detected position information has a first pitch, the second detected position information has a second pitch, the first composite position information has a first composite pitch, and the second pitch is (N-2) / (N-1) times the first pitch, whereby the first composite pitch is (N-2) times the first pitch or (N-1) times the second pitch, and N is an integer greater than 2.

[0019] In one or more embodiments of the present disclosure, the first sensed position information is N within a mechanical angle of 360 degrees. 2 the first detected position information has N(N-1) signal cycles within a mechanical angle of 360 degrees, and the second detected position information has N(N-1) signal cycles within a mechanical angle of 360 degrees, whereby the first composite position information has N signal cycles within a mechanical angle of 360 degrees, and N is an integer greater than 2.

[0020] In one or more embodiments of the present disclosure, the signal processing unit is configured to calculate second composite position information according to the third detected position information and the first composite position information based on a Vernier method.

[0021] In one or more embodiments of the present disclosure, the third sensed position information has a third pitch, the first composite position information has a first composite pitch, the second composite position information has a second composite pitch, and the first composite pitch is (N-1) / N times the third pitch, whereby the second composite pitch is (N-1) times the third pitch or N times the first composite pitch, and N is an integer greater than 2.

[0022] In one or more embodiments of the present disclosure, the third detected position information has (N-1) signal cycles within 360 mechanical degrees, and the first composite position information has N signal cycles within 360 mechanical degrees, thereby resulting in the second composite position information having 1 signal cycle within 360 mechanical degrees, and N is an integer greater than 2.

[0023] In one or more embodiments of the present disclosure, the signal processing unit is further configured to calculate a first position from the second composite position information, associate the first position with the first composite position information or the third detected position information and calculate a second position, and associate the second position with the first detected position information or the second detected position information and calculate a third position. [Effects of the Invention]

[0024] As described above, in the optical sensor assembly disclosed herein, the scale includes two pattern areas and the sensor includes three detection units. One detection unit is positioned to detect one pattern area, and the other two detection units are positioned to detect the other pattern area. Because the scale includes only two pattern areas, the optical sensor assembly requires only a small detection area, thereby increasing the mechanism assembly margin. Furthermore, the light-receiving elements of each detection unit are arranged out of phase with each other, providing higher environmental contamination resistance and a better assembly positioning margin, thereby improving the stability of the encoder. Furthermore, the encoding and decoding of the encoder using this optical sensor assembly uses three sets of incremental position signals and a vernier method, thereby enabling highly precise absolute position detection.

[0025] The above is only used to describe the problems that the present disclosure aims to solve, the technical solutions for solving the problems, and the effects that result therefrom, and specific details of the present disclosure will be introduced in detail in the following embodiments and related drawings. [Brief explanation of the drawings]

[0026] To make the above and other objects, features, advantages and embodiments of the present disclosure more clearly and comprehensibly, the accompanying drawings are described as follows: [Figure 1] FIG. 1 is a partial perspective view of an encoder according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a partial schematic view showing the scale in FIG. 1. [Figure 3] FIG. 2 is a schematic diagram showing a sensor, a light source, and a signal processing unit in FIG. 1. [Figure 4] FIG. 2 is a partial schematic diagram illustrating a first pattern area of ​​a scale according to one embodiment of the present disclosure. [Figure 5] FIG. 10 is a partial schematic diagram illustrating a second pattern area of ​​a scale according to an embodiment of the present disclosure. [Figure 6] FIG. 2 is a partial schematic diagram illustrating a first sensing portion of a sensor according to an embodiment of the present disclosure. [Figure 7] FIG. 4 is a partial schematic diagram illustrating a second sensing portion of a sensor according to an embodiment of the present disclosure. [Figure 8] FIG. 10 is a partial schematic diagram illustrating a third sensing portion of a sensor according to an embodiment of the present disclosure. [Figure 9] 4 is a schematic diagram showing a first detected position signal obtained by detecting a first pattern area using a first detection unit. FIG. [Figure 10] 4 is a schematic diagram showing first detected position information calculated from a first detected position signal. FIG. [Figure 11] 10A and 10B are schematic diagrams showing second and third detected position signals acquired by detecting a second pattern area using a second detection unit and a third detection unit, respectively. [Figure 12] 5A and 5B are schematic diagrams showing second detected position information and third detected position information calculated from the second detected position signal and the third detected position signal, respectively. [Figure 13A] FIG. 1 is a schematic diagram showing a 16-period signal. [Figure 13B] FIG. 1 is a schematic diagram showing a 15-cycle signal. [Figure 13C] FIG. 10 is a schematic diagram showing a difference signal between a signal with 16 periods and a signal with 15 periods. [Figure 13D]FIG. 13D is a schematic diagram representing the differential signal in FIG. 13C in unsigned 10-bit data format. [Figure 14] FIG. 2 is a schematic diagram illustrating position information obtained by a method for detecting the position of an encoder according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0027] In the following, in order to clearly illustrate and disclose multiple embodiments of the present disclosure in the drawings, many practical details are described in the following description. However, it should be understood that these practical details are not used to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and elements are simply illustrated in the drawings.

[0028] Please refer to FIG. 1, which is a partial perspective view of an encoder 100 according to one embodiment of the present disclosure. As shown in FIG. 1, in this embodiment, the encoder 100 includes an optical sensor assembly 110. The optical sensor assembly 110 includes a scale 111, a sensor 112, and a light source 113. The scale 111 and the sensor 112 are provided opposite each other and are relatively displaceable. For example, the scale 111 can move linearly or rotate relative to the sensor 112. The light source 113 is provided on the side of the sensor 112 facing the scale 111 and is arranged to emit light toward the scale 111. The sensor 112 is arranged to receive and detect light reflected by the scale 111.

[0029] Please refer to FIGS. 2 and 3. FIG. 2 is a partial schematic diagram showing the scale 111 in FIG. 1. FIG. 3 is a schematic diagram showing the sensor 112, the light source 113, and the signal processing unit 120 in FIG. 1. As shown in FIGS. 2 and 3, in this embodiment, the scale 111 includes a first pattern area 111a and a second pattern area 111b. The first pattern area 111a and the second pattern area 111b extend in a first direction D1 and are arranged in a second direction D2. The first direction D1 and the second direction D2 are perpendicular to each other. The sensor 112 is arranged to move relative to the scale 111 in the first direction D1 and includes a first detection unit 112a, a second detection unit 112b, and a third detection unit 112c. The first detection unit 112a is arranged to detect changes in the first pattern area 111a in the first direction D1. The second detection unit 112b is arranged to detect changes in the second pattern area 111b in the first direction D1. The third detector 112c is disposed to detect a change in the second direction D2 of the second pattern region 111b.

[0030] In some embodiments where the encoder 100 is linear, the first direction D1 is the X direction and the second direction D2 is the Y direction. In some embodiments where the encoder 100 is rotary, the first direction D1 is the circumferential (Θ) direction and the second direction D2 is the radial (R) direction.

[0031] Please refer to FIG. 4, which is a partial schematic diagram showing a first pattern region 111a of a scale 111 according to one embodiment of the present disclosure. As shown in FIG. 4, in this embodiment, the first pattern region 111a of the scale 111 includes a plurality of first patterns G1 periodically arranged in a first direction D1. The first patterns G1 have an elongated shape. The first patterns G1 extend in a second direction D2 and are arranged in order in the first direction D1. The first patterns G1 have a first pitch P1 in the first direction D1. In some embodiments, when the scale 111 employs a reflective architecture, the first patterns G1 are highly reflective, and the regions other than the first patterns G1 are low-reflective. In some embodiments, when the scale 111 employs a transmissive architecture, the first patterns G1 are highly translucent, and the regions other than the first patterns G1 are low-translucent.

[0032] Please refer to FIG. 5, which is a partial schematic diagram showing the second pattern region 111b of the scale 111 according to one embodiment of the present disclosure. As shown in FIG. 5, in this embodiment, the second pattern region 111b of the scale 111 includes a plurality of second patterns G2 periodically arranged in the first direction D1 and the second direction D2. Specifically, the second patterns G2 are arranged in a plurality of rows C. These rows C have a second pitch P2 in the first direction D1. The second patterns G2 in each row C have a different pitch P2' in the second direction D2. In other words, the second patterns G2 in the second pattern region 111b form a two-dimensional pattern.

[0033] In this embodiment, the shape of each second pattern G2 is rectangular, but the present disclosure is not limited thereto. In some embodiments, when the scale 111 employs a reflective architecture, the second pattern G2 is a highly reflective area, and the areas other than the second pattern G2 are low-reflective areas. In some embodiments, when the scale 111 employs a transmissive architecture, the second pattern G2 is a highly translucent area, and the areas other than the second pattern G2 are low-translucent areas.

[0034] In particular, the second patterns G2 arranged along the first direction D1 are gradually shifted in the second direction D2. Specifically, as shown in FIG. 5, the rows C, which have been spaced apart by a distance of N times the second pitch P2 along the first direction D1, are gradually shifted by a distance of one pitch P2' in the second direction D2, where N is an integer greater than 2. In other words, each second pattern G2 has a third pitch P3 in the first direction D1, and the third pitch P3 is N times the second pitch P2. Correspondingly, after the sensor 112 moves a distance of N times the second pitch P2 in the first direction D1 relative to the scale 111, the second detection unit 112b generates N periodic signals, and the third detection unit 112c generates one periodic signal.

[0035] With the above-described structural configuration, while the sensor 112 and the scale 111 move relatively in the first direction D1, the sensor 112 can perform C detection for the first pattern area 111a using the first detection portion 112a, and can simultaneously perform C detection for the second pattern area 111b using the second detection portion 112b and the third detection portion 112c. Because the scale 111 includes only two pattern areas, the optical sensor assembly 110 only requires a small detection area, thereby increasing the mechanism assembly margin.

[0036] In some embodiments, N is an integer greater than 2. For example, as shown in FIG. 5, N is 12 (i.e., the rows C that have traveled a distance of 12 times the second pitch P2 along the first direction D1 are gradually shifted by a distance of one pitch P2′ in the second direction D2), although the present disclosure is not limited thereto.

[0037] Please refer to Figures 6, 7, and 8. Figure 6 is a partial schematic diagram showing a first detection unit 112a of a sensor 112 according to one embodiment of the present disclosure. Figure 7 is a partial schematic diagram showing a second detection unit 112b of a sensor 112 according to one embodiment of the present disclosure. Figure 8 is a partial schematic diagram showing a third detection unit 112c of a sensor 112 according to one embodiment of the present disclosure. As shown in Figures 6 to 8, the first detection unit 112a includes a plurality of light receiving elements A1+, B1+, A1-, and B1- arranged in a phased array. The second detection unit 112b includes a plurality of light receiving elements A2+, B2+, A2-, and B2- arranged in a phased array. The third detection unit 112c includes a plurality of light receiving elements A3+, B3+, A3-, and B3- arranged in a phased array. Specifically, the light receiving elements A1+, B1+, A1-, and B1- of the first detection unit 112a are arranged with a periodic phase shift in the first direction D1, i.e., the light receiving elements A1+, B1+, A1-, and B1- are arranged in an alternating sequence that is repeated over multiple cycles. The light receiving elements A2+, B2+, A2-, and B2- of the second detection unit 112b are arranged with a periodic phase shift in the first direction D1, i.e., the light receiving elements A2+, B2+, A2-, and B2- are arranged in an alternating sequence that is repeated over multiple cycles. The light receiving elements A3+, B3+, A3-, and B3- of the third detecting unit 112c are arranged periodically with a phase shift in the third direction, i.e., the light receiving elements A3+, B3+, A3-, and B3- are arranged alternately in multiple cycles. By adopting a phase shift arrangement, the first detecting unit 112a, the second detecting unit 112b, and the third detecting unit 112c have higher resistance to environmental contamination and better assembly positioning margins, thereby improving the stability of the encoder 100.

[0038] Please refer to Figure 9, which is a schematic diagram showing a first detected position signal obtained by detecting the first pattern area 111a using the first detection unit 112a. As shown in Figure 9, in this embodiment, the first detection unit 112a detects a change in the first pattern area 111a in the first direction D1 and then generates a corresponding first detected position signal. Specifically, the light receiving elements A1+, B1+, A1-, and B1- of the first detection unit 112a generate first detected position signals SA1+, SB1+, SA1-, and SB1-, respectively.

[0039] 3, in this embodiment, the encoder 100 further includes a signal processing unit 120 (shown by a dashed line). The signal processing unit 120 is connected to the sensor 112 and is configured to process the first sensed position signals SA1+, SB1+, SA1-, SB1- generated by the first sensing portion 112a. In this embodiment, the signal processing unit 120 is integrated with the sensor 112, but the present disclosure is not limited thereto. In practical applications, the signal processing unit 120 may not be integrated with the sensor 112 and may be connected via additional components.

[0040] Please refer to Figure 10, which is a schematic diagram showing first detected position information calculated from the first detected position signals. In this embodiment, the signal processing unit 120 is configured to calculate the first detected position information (shown in Figure 10) from the first detected position signals SA1+, SB1+, SA1-, SB1- (shown in Figure 9). For example, the first detected position information can be calculated by an inverse tangent function (i.e., ATAN function). The first detected position information also has a first pitch P1.

[0041] Please refer to FIG. 11, which is a schematic diagram showing the second and third detected position signals obtained by detecting the second pattern area 111b using the second detection unit 112b and the third detection unit 112c, respectively. As shown in FIG. 11, in this embodiment, the second detection unit 112b detects a change in the second pattern area 111b in the first direction D1 and then generates second detected position signals SA2+, SB2+, SA2-, and SB2-, respectively. The third detection unit 112c detects a change in the second pattern area 111b in the second direction D2 and then generates third detected position signals SA3+, SB3+, SA3-, and SB3-, respectively.

[0042] Please refer to FIG. 12, which is a schematic diagram showing second detected position information and third detected position information calculated from the second detected position signal and the third detected position signal, respectively. In this embodiment, the signal processing unit 120 is further configured to calculate second detected position information (shown in FIG. 12) from the second detected position signals SA2+, SB2+, SA2-, and SB2- (shown in FIG. 11). For example, the second detected position information can be calculated using an inverse tangent function. The second detected position information also has a second pitch P2. The signal processing unit 120 is further configured to calculate third detected position information (shown in FIG. 12) from the third detected position signals SA3+, SB3+, SA3-, and SB3- (shown in FIG. 11). For example, the third detected position information can be calculated using an inverse tangent function. The third detected position information also has a third pitch P3.

[0043] In this embodiment, the signal processing unit 120 is further configured to generate first composite position information based on the first detected position information and the second detected position information, and to generate second composite position information based on the third detected position information and the first composite position information. Specifically, the signal processing unit 120 is configured to calculate the first composite position information based on the Vernier method using the first detected position information and the second detected position information. The signal processing unit 120 is further configured to calculate the second composite position information based on the Vernier method using the third detected position information and the first composite position information. A brief explanation of the principle of the Vernier method is as follows.

[0044] Please refer to Figures 13A, 13B, 13C, and 13D. Figure 13A is a schematic diagram showing a 16-period signal. Figure 13B is a schematic diagram showing a 15-period signal. Figure 13C is a schematic diagram of a differential signal between a 16-period signal and a 15-period signal. Figure 13D is a schematic diagram showing the differential signal in Figure 13C in an unsigned 10-bit data format. As shown in Figures 13A to 13D, the differential signal in Figure 13C can be obtained by subtracting the 16-period signal in Figure 13A from the 15-period signal in Figure 13B. Furthermore, by converting the differential signal in Figure 13C into an unsigned 10-bit data format, the single-period signal shown in Figure 13D can be obtained.

[0045] In some embodiments where encoder 100 is linear, the first resultant position information has a first resultant pitch P1. The second pitch P2 of the second sensed position information is (N-2) / (N-1) times the first pitch P1 of the first sensed position information, such that the first resultant pitch P1 is (N-2) times the first pitch P1 or (N-1) times the second pitch P2, where N is an integer greater than 2.

[0046] In some embodiments where the encoder 100 is linear, the second composite position information has a second composite pitch PS2. The first composite pitch PS1 is (N-1) / N times the third pitch P3, such that the second composite pitch PS2 is (N-1) times the third pitch P3 or N times the first composite pitch PS1, where N is an integer greater than 2.

[0047] For example, under the conditions that N is 33, the first pitch P1 is 64 μm, the second pitch P2 is 62 μm, and the third pitch P3 is 2,046 μm, the signal processing unit 120 can generate first composite position information in which the first composite pitch PS1 is 1,984 μm and second composite position information in which the second composite pitch PS2 is 65,472 μm.

[0048] For example, under the conditions that N is 65, the first pitch P1 is 64 μm, the second pitch P2 is 63 μm, and the third pitch P3 is 4,095 μm, the signal processing unit 120 can generate first composite position information in which the first composite pitch PS1 is 4,032 μm and second composite position information in which the second composite pitch PS2 is 262,080 μm.

[0049] In some embodiments where the encoder 100 is rotary, the first sensed position information is N within 360 mechanical degrees. 2 The first sensed position information has N(N-1) signal cycles within a mechanical angle of 360 degrees, and the second sensed position information has N(N-1) signal cycles within a mechanical angle of 360 degrees, whereby the first combined position information has N signal cycles within a mechanical angle of 360 degrees, where N is an integer greater than 2.

[0050] In some embodiments where encoder 100 is rotary, the third sensed position information has (N-1) signal cycles within 360 mechanical degrees, and the first resultant position information has N signal cycles within 360 mechanical degrees, such that the second resultant position information has 1 signal cycle within 360 mechanical degrees, where N is an integer greater than 2.

[0051] For example, when N is 32 and the first detection position information, the second detection position information, and the third detection position information have 1,024, 992, and 31 signal cycles within 360 mechanical degrees, respectively, the signal processing unit 120 can generate first composite position information having 32 signal cycles within 360 mechanical degrees and second composite position information having 1 signal cycle within 360 mechanical degrees.

[0052] For example, when N is 50 and the first detection position information, the second detection position information, and the third detection position information have 2,500, 2,450, and 49 signal cycles within 360 mechanical degrees, respectively, the signal processing unit 120 can generate first composite position information having 50 signal cycles within 360 mechanical degrees and second composite position information having 1 signal cycle within 360 mechanical degrees.

[0053] The second combined position information calculated by the signal processing unit 120 can be initial absolute position information. The third detected position information or the first combined position information calculated by the signal processing unit 120 can be medium-accuracy position information. The first detected position information or the second detected position information can be high-accuracy position information.

[0054] Please refer to FIG. 14, which is a schematic diagram illustrating position information obtained by the position detection method of the encoder 100 according to one embodiment of the present disclosure. As shown in FIG. 14, in this embodiment, the signal processing unit 120 is further configured to calculate a first position a from the second composite position information (i.e., initial absolute position information). The signal processing unit 120 is further configured to associate the first position a with the first composite position information or the third detected position information (i.e., medium-precision position information) and calculate a second position b, as shown in the figure, which is the position of the second cycle. The signal processing unit 120 is further configured to associate the second position b with the first detected position information or the second detected position information (i.e., high-precision position information) and calculate a third position c, as shown in the figure, which is the position of the fifth cycle, as the third position c is a high-precision absolute position. In this gradual position calculation step, the low-precision initial absolute position is associated with a medium-precision incremental position, and then the medium-precision incremental position is associated with a high-precision incremental position, and the calculated position information is a high-precision absolute position. As a result, the encoder 100 of this embodiment can achieve highly precise absolute position detection.

[0055] As is clear from the detailed description of specific embodiments of the present disclosure, in the optical sensor assembly of the present disclosure, the scale includes two pattern areas and the sensor includes three detection units. One detection unit is positioned to detect one pattern area, and the other two detection units are positioned to detect the other pattern area. Because the scale includes only two pattern areas, the optical sensor assembly only requires a small detection area, thereby increasing the mechanism assembly margin. In addition, the light-receiving elements of each detection unit are arranged out of phase with each other, which provides higher environmental contamination resistance and a better assembly positioning margin, thereby improving the stability of the encoder. Furthermore, the encoding and decoding of the encoder using this optical sensor assembly uses three sets of incremental position signals and a vernier method, thereby achieving high-precision absolute position detection.

[0056] Although the present disclosure has been disclosed in the above embodiments, the above embodiments do not limit the present disclosure, and anyone skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure. Therefore, the scope of protection of the present disclosure should be determined based on the scope of the patent application to be attached later. [Explanation of symbols]

[0057] 100: Encoder 110: Optical sensor assembly 111:Scale 111a: First pattern area 111b: second pattern area 112: Sensor 112a: First detection unit A1+, A1-, B1+, B1-, A2+, A2-, B2+, B2-, A3+, A3-, B3+, B3-: Photodetector 112b: Second detection unit 112c: Third detection unit 113: Light source 120: Signal processing unit a: 1st position b: 2nd position c: 3rd position C: line D1: 1st direction D2:Second direction G1: First pattern G2: Second pattern P1: First pitch P2: Second pitch P2': Pitch P3: Third pitch PS1: First synthetic pitch PS2: Second synthetic pitch SA1+, SA1-, SB1+, SB1-: First detection position signal SA2+, SA2-, SB2+, SB2-: Second detection position signal SA3+, SA3-, SB3+, SB3-: Third detection position signal

Claims

1. a scale including a first pattern area including a plurality of first patterns periodically arranged in a first direction, and a second pattern area including a plurality of second patterns periodically arranged in the first direction and a second direction; a sensor including a first detection unit arranged to detect a change in the first direction of the first pattern area, a second detection unit arranged to detect a change in the second pattern area in the first direction, and a third detection unit arranged to detect a change in the second pattern area in the second direction, the sensor being arranged to move relative to the scale in the first direction; a light source arranged to emit light toward the scale; An optical sensor assembly comprising:

2. The optical sensor assembly of claim 1 , wherein the second patterns arranged along the first direction are gradually offset in the second direction.

3. 3. The optical sensor assembly of claim 2, wherein the second patterns are arranged in a plurality of rows, the rows having a pitch in the first direction, the second patterns in each row having a different pitch in the second direction, and the rows passing through a distance of N times the pitch along the first direction are progressively offset by a distance of one of the different pitches in the second direction, and N is an integer greater than 2.

4. 4. The optical sensor assembly of claim 3, wherein after the sensor moves a distance of N times the pitch in the first direction relative to the scale, the second sensing portion generates N periodic signals and the third sensing portion generates one periodic signal.

5. The optical sensor assembly according to claim 1 , wherein the light receiving elements of the first detection unit, the second detection unit and the third detection unit are arranged with a phase shift.

6. an optical sensor assembly and a signal processing unit; The optical sensor assembly includes: a scale including a first pattern area including a plurality of first patterns periodically arranged in a first direction, and a second pattern area including a plurality of second patterns periodically arranged in the first direction and a second direction; a sensor arranged to move relative to the scale in the first direction, the sensor including: a first detector arranged to detect a change in the first pattern area in the first direction and generating a first detected position signal in response; a second detector arranged to detect a change in the second pattern area in the first direction and generating a second detected position signal in response; and a third detector arranged to detect a change in the second pattern area in the second direction and generating a third detected position signal in response; Including, The signal processing unit calculating first detected position information, second detected position information, and third detected position information from the first detected position signal, the second detected position signal, and the third detected position signal, respectively; calculating first combined position information from the first detected position information and the second detected position information; calculating second combined position information using the third detected position information and the first combined position information; an encoder connected to the sensor and arranged to:

7. The encoder according to claim 6 , wherein the second patterns arranged along the first direction are gradually shifted in the second direction.

8. 8. The encoder of claim 7, wherein the second patterns are arranged in a plurality of rows, the rows having a pitch in the first direction, the second patterns in each row having a different pitch in the second direction, and the rows passing through a distance of N times the pitch along the first direction are progressively offset by a distance of one of the different pitches in the second direction, and N is an integer greater than 2.

9. 9. The encoder of claim 8, wherein after the sensor moves a distance of N times the pitch in the first direction relative to the scale, the second sensing unit generates N periodic signals and the third sensing unit generates one periodic signal.

10. The encoder according to claim 6, wherein the light receiving elements of the first detector, the second detector, and the third detector are arranged with a phase shift.

11. The encoder according to claim 6 , wherein the signal processing unit is configured to calculate the first composite position information based on the first detected position information and the second detected position information in a Vernier system.

12. 12. The encoder of claim 11, wherein the first detected position information has a first pitch, the second detected position information has a second pitch, the first composite position information has a first composite pitch, and the second pitch is (N-2) / (N-1) times the first pitch, whereby the first composite pitch is (N-2) times the first pitch or (N-1) times the second pitch, and N is an integer greater than 2.

13. The first detected position information is N within a mechanical angle of 360 degrees. ２ the second sensed position information has N(N-1) signal cycles within 360 mechanical degrees, whereby the first composite position information has N signal cycles within 360 mechanical degrees, and N is an integer greater than 2.

14. The encoder according to claim 6 , wherein the signal processing unit is configured to calculate the second composite position information based on the third detected position information and the first composite position information based on a Vernier method.

15. 15. The encoder of claim 14, wherein the third sensed position information has a third pitch, the first composite position information has a first composite pitch, the second composite position information has a second composite pitch, and the first composite pitch is (N-1) / N times the third pitch, whereby the second composite pitch is (N-1) times the third pitch or N times the first composite pitch, and N is an integer greater than 2.

16. 15. The encoder of claim 14, wherein the third detected position information has (N-1) signal cycles within 360 mechanical degrees, and the first resultant position information has N signal cycles within 360 mechanical degrees, thereby causing the second resultant position information to have one signal cycle within 360 mechanical degrees, and N is an integer greater than 2.

17. The signal processing unit further comprises: calculating a first position from the second combined position information; Correlating the first position with the first combined position information or the third detected position information to calculate a second position; Correlating the second position with the first detected position information or the second detected position information to calculate a third position; 14. An encoder according to any one of claims 6 to 13, arranged to:

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