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 multiple first patterns periodically arranged in a first direction and a second direction, and a second pattern area comprising multiple second patterns periodically arranged in the first direction and the 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, a third sensing area configured to sense a change of the first pattern area in the second direction, and a fourth 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 in the field of precision equipment control, such as measuring motor rotation speed 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 code to obtain absolute position information, and its main architecture includes an optical transmitter, an optical receiver, a code disk, and a processing circuit. The optical transmitter and the optical 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 optical receiver also shrinks significantly, causing external environmental contamination such as oil stains, dirt, and particles to 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 in order to overcome the problems and shortcomings of the known technology, achieve 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 to which the same is applied, which can solve the above problems.

[0007] To achieve the above object, according to one embodiment of the present disclosure, an optical sensor assembly includes a scale, a sensor, and a light source. The scale q includes a first pattern region including a plurality of first patterns periodically arranged in a first direction and a second direction, and a second pattern region including a plurality of second patterns periodically arranged in the first direction and the second direction. The sensor includes a first detector arranged to detect changes in the first pattern region in the first direction, a second detector arranged to detect changes in the second pattern region in the first direction, a third detector arranged to detect changes in the first pattern region in the second direction, and a fourth detector arranged to detect changes in the second pattern region 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 first patterns arranged along the first direction are gradually offset in the second direction.

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

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

[0011] In one or more embodiments of the present disclosure, the second patterns arranged along the first direction are gradually offset in the second direction.

[0012] In one or more embodiments of the present disclosure, the second patterns are arranged in a plurality of rows, the rows having a pitch in a first direction, the second patterns in each row having a different pitch in a second direction, and the rows after N times the pitch distance along the first direction are progressively offset by one of the different pitch distances in the second direction, where N is an integer greater than 2.

[0013] In one or more embodiments of the present disclosure, after the sensor moves N times the pitch distance in the first direction relative to the scale, the second sensing unit generates N periodic signals and the fourth sensing unit generates one periodic signal.

[0014] In one or more embodiments of the present disclosure, the light receiving elements of the first detector, the second detector, the third detector, and the fourth detector are arranged out of phase with each other.

[0015] To achieve the above object, according to one embodiment of the present disclosure, in one or more embodiments 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 direction, and a second pattern area including a plurality of second patterns periodically arranged in the first direction and a second direction, and the sensor includes a first detector arranged to detect changes in the first pattern area in the first direction and correspondingly generate a first detected position signal, a second detector arranged to detect changes in the second pattern area in the first direction and correspondingly generate a second detected position signal, a third detector arranged to detect changes in the first pattern area in the second direction and correspondingly generate a third detected position signal, and a fourth detector arranged to detect changes in the second pattern area in the second direction and correspondingly generate a fourth detected position signal, and is arranged to move relative to the scale in the first direction. The signal processing unit is connected to the sensor and arranged to calculate first detection position information, second detection position information, third detection position information, and fourth detection position information using the first detection position signal, second detection position signal, third detection position signal, and fourth detection position signal, respectively; calculate first combined position information using the first detection position information and the second detection position information; calculate second combined position information using the third detection position information and the first combined position information; calculate third combined position information using the fourth detection position information and the first combined position information; and calculate fourth combined position information using the second combined position information and the third combined position information.

[0016] In one or more embodiments of the present disclosure, the first patterns arranged along the first direction are gradually offset in the second direction.

[0017] In one or more embodiments of the present disclosure, the first pattern is arranged in a plurality of rows, the rows having a pitch in a first direction, the first pattern in each row having a different pitch in a second direction, and the rows after M times the pitch distance along the first direction are progressively offset by one of the different pitch distances in the second direction, where M is an integer greater than 2.

[0018] In one or more embodiments of the present disclosure, after the sensor moves M times the pitch distance in the first direction relative to the scale, the first sensing unit generates M periodic signals and the third sensing unit generates one periodic signal.

[0019] In one or more embodiments of the present disclosure, the second patterns arranged along the first direction are gradually offset in the second direction.

[0020] In one or more embodiments of the present disclosure, the second patterns are arranged in a plurality of rows, the rows having a pitch in a first direction, the second patterns in each row having a different pitch in a second direction, and the rows following N times the pitch distance along the first direction are progressively offset by one other pitch distance in the second direction, where N is an integer greater than 2.

[0021] In one or more embodiments of the present disclosure, after the sensor moves N times the pitch distance in the first direction relative to the scale, the second sensing unit generates N periodic signals and the fourth sensing unit generates one periodic signal.

[0022] In one or more embodiments of the present disclosure, the light receiving elements of the first detector, the second detector, the third detector, and the fourth detector are arranged out of phase with each other.

[0023] 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.

[0024] 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.

[0025] The signal processing unit is configured to calculate third combined position information according to the fourth detected position information and the first combined position information based on a Vernier method.

[0026] The signal processing unit is configured to calculate fourth composite position information according to the second composite position information and the third composite position information based on a Vernier method. [Effects of the Invention]

[0027] As described above, in the optical sensor assembly disclosed herein, the scale includes two pattern areas and the sensor includes four detection elements. Two of the detection elements are positioned to detect one of the pattern areas, and the other two detection elements 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 assembly margin of the mechanism. Furthermore, the light-receiving elements of each detection element 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 four sets of incremental position signals and a vernier method, thereby enabling high-precision absolute position detection.

[0028] The above is used only to describe the problems to be solved by the present disclosure, the technical means for solving the problems, and the effects thereof, and specific details of the present disclosure will be described in detail in the following embodiments and related drawings. [Brief explanation of the drawings]

[0029] 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 the sensor, light source, and 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 one embodiment of the present disclosure. [Figure 7] FIG. 2 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 section of a sensor according to an embodiment of the present disclosure. [Figure 9] FIG. 10 is a partial schematic diagram illustrating a fourth sensing section of a sensor according to an embodiment of the present disclosure. [Figure 10] 5A and 5B are schematic diagrams showing first detected position signals acquired by detecting a first pattern area using a first detection unit and a third detection unit, respectively. [Figure 11] 5A and 5B are schematic diagrams showing first and third detected position information calculated from the first and third detected position signals, respectively. [Figure 12] 10A and 10B are schematic diagrams showing second and fourth detected position signals acquired by detecting a second pattern area using a second detection unit and a fourth detection unit, respectively. [Figure 13] 6A and 6B are schematic diagrams showing second and fourth detected position information calculated from second and fourth detected position signals, respectively. [Figure 14A] FIG. 1 is a schematic diagram showing a 16-period signal. [Figure 14B]FIG. 1 is a schematic diagram showing a 15-cycle signal. [Figure 14C] FIG. 10 is a schematic diagram showing a difference signal between a signal with 16 periods and a signal with 15 periods. [Figure 14D] FIG. 14D is a schematic diagram showing the difference signal in FIG. 14C in unsigned 10-bit data format. [Figure 15] FIG. 2 is a schematic diagram illustrating an encoder position detection method for obtaining position information according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0030] 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 applied to limit the present disclosure. That is, in some embodiments of the present disclosure, these practical details are not necessary. Furthermore, in order to simplify the drawings, some conventional structures and elements are simply illustrated in the drawings.

[0031] 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 positioned to emit light toward the scale 111. The sensor 112 is positioned to receive and detect light reflected by the scale 111.

[0032] Please refer to Figures 2 and 3. Figure 2 is a partial schematic diagram showing the scale 111 in Figure 1. Figure 3 is a schematic diagram showing the sensor 112, light source 113, and signal processing unit 120 in Figure 1. As shown in Figures 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, a third detection unit 112c, and a fourth detection unit 112d. The first detection unit 112a is arranged to detect changes in the first pattern area 111a in the first direction D1. The second detector 112b is arranged to detect changes in the second pattern region 111b in the first direction D1. The third detector 112c is arranged to detect changes in the first pattern region 111a in the second direction D2. The fourth detector 112d is arranged to detect changes in the second pattern region 111b in the second direction D2.

[0033] In some embodiments where the encoder 100 is linear, the first direction D1 is the X direction, while 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, while the second direction D2 is the radial (R) direction.

[0034] 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 and a second direction D2. Specifically, the first patterns G1 are arranged in a plurality of rows C1. These rows C1 have a first pitch P1 in the first direction D1. The first patterns G1 in each row C1 have a different pitch P1' in the second direction D2. In other words, the first patterns G1 in the first pattern region 111a form a two-dimensional pattern.

[0035] In this embodiment, each first pattern G1 has a rectangular shape, but the present disclosure is not limited thereto. In some embodiments, the scale 111 uses a reflective architecture, where the first pattern G1 is a highly reflective region, and the regions other than the first pattern G1 are low-reflective regions. In some embodiments, the scale 111 uses a transmissive architecture, where the first pattern G1 is a highly transmissive region, and the regions other than the first pattern G1 are low-transmissive regions.

[0036] In particular, the first patterns G1 arranged along the first direction D1 are gradually shifted in the second direction D2. Specifically, as shown in FIG. 4, the rows C1, which have moved M times the distance of the first pitch P1 along the first direction D1, are gradually shifted in the second direction D2 by one pitch P1', where M is an integer greater than 2. In other words, each first pattern G1 has a third pitch P3 in the first direction D1, and the third pitch P3 is M times the first pitch P1. Correspondingly, after the sensor 112 moves M times the distance of the first pitch P1 in the first direction D1 relative to the scale 111, the first detection unit 112a generates M periodic signals, and the third detection unit 112c generates one periodic signal.

[0037] In some embodiments, M is an integer greater than 2. For example, as shown in FIG. 4, M is 12 (i.e., the rows C1 that have traveled 12 times the distance of the first pitch P1 along the first direction D1 are gradually shifted by a distance of one pitch P1′ in the second direction D2), although the present disclosure is not limited thereto.

[0038] 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 C2. These rows C2 have a second pitch P2 in the first direction D1. The second patterns G2 in each row C2 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.

[0039] In this embodiment, each second pattern G2 has a rectangular shape, but the present disclosure is not limited thereto. In some embodiments, the scale 111 uses a reflective architecture, where the second pattern G2 is a highly reflective region, and the regions other than the second pattern G2 are low-reflective regions. In some embodiments, the scale 111 uses a transmissive architecture, where the second pattern G2 is a highly transmissive region, and the regions other than the second pattern G2 are low-transmissive regions.

[0040] 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 C2, which have moved N times the distance of the second pitch P2 along the first direction D1, are gradually shifted in the second direction D2 by one pitch P2', where N is an integer greater than 2. In other words, each second pattern G2 has a fourth pitch P4 in the first direction D1, and the fourth pitch P4 is N times the second pitch P2. Correspondingly, after the sensor 112 moves N times the distance of 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 fourth detection unit 112d generates one periodic signal.

[0041] With this structural arrangement, while the sensor 112 and the scale 111 move relatively in the first direction D1, the sensor 112 can simultaneously detect the first pattern area 111a using the first detection portion 112a and the third detection portion 112c, and simultaneously detect the second pattern area 111b using the second detection portion 112b and the fourth detection portion 112d. Because the scale 111 includes only two pattern areas, the optical sensor assembly 110 only requires a small detection area, thereby increasing the assembly margin of the mechanism.

[0042] In some embodiments, N is an integer greater than 2. For example, as shown in FIG. 5, N is 12 (i.e., the rows C2 that have traveled 12 times the distance of the second pitch P2 along the first direction D1 are gradually offset in the second direction D2 by a distance of one pitch P2′), although the present disclosure is not limited thereto.

[0043] Please refer to Figures 6, 7, 8, and 9. Figure 6 is a partial schematic view showing a first detection unit 112a of a sensor 112 according to one embodiment of the present disclosure. Figure 7 is a partial schematic view showing a second detection unit 112b of a sensor 112 according to one embodiment of the present disclosure. Figure 8 is a partial schematic view showing a third detection unit 112c of a sensor 112 according to one embodiment of the present disclosure. Figure 9 is a partial schematic view showing a fourth detection unit 112d of a sensor 112 according to one embodiment of the present disclosure. As shown in Figures 6 to 9, the first detection unit 112a includes a plurality of light receiving elements A1+, B1+, A1-, and B1- that are arranged with a phase shift. The second detection unit 112b includes a plurality of light receiving elements A2+, B2+, A2-, and B2- that are arranged with a phase shift. The third detection unit 112c includes a plurality of light receiving elements A3+, B3+, A3-, and B3- that are arranged with a phase shift. The fourth detector 112d includes a plurality of light-receiving elements A4+, B4+, A4-, and B4- that are arranged with a phase shift. Specifically, the light-receiving elements A1+, B1+, A1-, and B1- of the first detector 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 alternately arranged in multiple periods. The light-receiving elements A2+, B2+, A2-, and B2- of the second detector 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 alternately arranged in multiple periods. The light receiving elements A3+, B3+, A3−, and B3− of the third detection unit 112c are arranged with a periodic phase shift in the second direction D2, i.e., the light receiving elements A3+, B3+, A3−, and B3− are alternately arranged in multiple periods. The light receiving elements A4+, B4+, A4−, and B4− of the fourth detection unit 112d are arranged with a periodic phase shift in the second direction D2, i.e., the light receiving elements A4+, B4+, A4−, and B4− are alternately arranged in multiple periods. When the light receiving elements are arranged with a phase shift, the first detection unit 112a, the second detection unit 112b, the third detection unit 112c, and the fourth detection unit 112d have higher resistance to environmental contamination and a better assembly positioning margin, thereby improving the stability of the encoder 100.

[0044] Please refer to FIG. 10, which is a schematic diagram illustrating the first and third detected position signals obtained by detecting the first pattern area 111a using the first detection unit 112a and the third detection unit 112c, respectively. As shown in FIG. 10, 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. The third detection unit 112c detects a change in the first pattern area 111a in the second direction D2 and then generates a corresponding third detected position signal. Specifically, the light receiving elements A3+, B3+, A3-, and B3- of the third detecting section 112c generate third detected position signals SA3+, SB3+, SA3-, and SB3-, respectively.

[0045] 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 configured to process the first detected position signals SA1+, SB1+, SA1-, and SB1- generated by the first detection unit 112a and the third detected position signals SA3+, SB3+, SA3-, and SB3- generated by the third detection unit 112c. Although the signal processing unit 120 in this embodiment is integrated into the sensor 112, the present disclosure is not limited thereto. In actual applications, the signal processing unit 120 and the sensor 112 may be connected via additional components rather than being integrated.

[0046] Please refer to FIG. 11, which is a schematic diagram showing first and third detected position information calculated from the first and third detected position signals, respectively. In this embodiment, the signal processing unit 120 is configured to calculate the first detected position information (shown in FIG. 11) according to the first detected position signals SA1+, SB1+, SA1-, and SB1- (shown in FIG. 10). For example, the first detected position information can be calculated by an inverse tangent function (i.e., an ATAN function). The first detected position information also has a first pitch P1. In addition, the signal processing unit 120 is further configured to calculate the third detected position information (shown in FIG. 11) according to the third detected position signals SA3+, SB3+, SA3-, and SB3- (shown in FIG. 10). For example, the third detected position information can be calculated by an inverse tangent function. The third detected position information also has a third pitch P3.

[0047] 12 is a schematic diagram illustrating the second and fourth detected position signals obtained by detecting the second pattern region 111b using the second detection unit 112b and the fourth detection unit 112d, respectively. As shown in FIG. 12, in this embodiment, after the second detection unit 112b detects a change in the second pattern region 111b in the first direction D1, it generates second detected position signals SA2+, SB2+, SA2-, and SB2-. After the fourth detection unit 112d detects a change in the second pattern region 111b in the second direction D2, it generates fourth detected position signals SA4+, SB4+, SA4-, and SB4-.

[0048] Please refer to FIG. 13, which is a schematic diagram showing second detected position information and fourth detected position information calculated from the second detected position signal and the fourth detected position signal, respectively. In this embodiment, the signal processing unit 120 is further configured to calculate second detected position information (shown in FIG. 13) according to the second detected position signals SA2+, SB2+, SA2-, and SB2- (shown in FIG. 12). For example, the second detected position information can be calculated by 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 fourth detected position information (shown in FIG. 13) according to the fourth detected position signals SA4+, SB4+, SA4-, and SB4- (shown in FIG. 12). For example, the fourth detected position information can be calculated by an inverse tangent function. The fourth detected position information also has a fourth pitch P4.

[0049] In this embodiment, the signal processing unit 120 is further configured to calculate first combined position information using the first detected position information and the second detected position information, calculate second combined position information using the third detected position information and the first combined position information, calculate third combined position information using the fourth detected position information and the first combined position information, and calculate fourth combined position information using the second combined position information and the third combined position information. Specifically, the signal processing unit 120 is configured to calculate the first combined position information using the first detected position information and the second detected position information based on the Vernier method. The signal processing unit 120 is further configured to calculate the second combined position information using the third detected position information and the first combined position information based on the Vernier method. The signal processing unit 120 is further configured to calculate the third combined position information using the fourth detected position information and the first combined position information based on the Vernier method. The signal processing unit 120 is further configured to calculate the fourth combined position information using the second combined position information and the third combined position information based on the Vernier method. The principle of the Vernier method is briefly explained as follows.

[0050] Please refer to Figures 14A, 14B, 14C, and 14D. Figure 14A is a schematic diagram showing a 16-cycle signal. Figure 14B is a schematic diagram showing a 15-cycle signal. Figure 14C is a schematic diagram showing a differential signal between a 16-cycle signal and a 15-cycle signal. Figure 14D is a schematic diagram showing the differential signal in Figure 14C in an unsigned 10-bit data format. As shown in Figures 14A to 14D, the differential signal in Figure 14C can be obtained by subtracting the 16-cycle signal in Figure 14A from the 15-cycle signal in Figure 14B. Furthermore, by converting the differential signal in Figure 14C into an unsigned 10-bit data format, the single-cycle signal shown in Figure 14D can be obtained.

[0051] In some embodiments in which encoder 100 is linear, N is equal to M+1. The first resultant position information has a first resultant pitch P1. The second pitch P2 of the second sensed position information is (M-1) / M times the first pitch P1 of the first sensed position information, so that the first resultant pitch P1 is (M-1) times the first pitch P1 or M times the second pitch P2, where M is an integer greater than 2.

[0052] In some embodiments in which the encoder 100 is linear, the second composite position information has a second composite pitch PS2. The first composite pitch PS1 is (M-1) / M times the third pitch P3, so the second composite pitch PS2 is (M-1) times the third pitch P3 or M times the first composite pitch PS1, where N is an integer greater than 2.

[0053] In some embodiments in which the encoder 100 is linear, the third composite position information has a third composite pitch PS3. Since the first composite pitch PS1 is M / (M+1) times the fourth pitch P4, the third composite pitch PS3 is M times the fourth pitch P4 or (M+1) times the first composite pitch PS1, where M is an integer greater than 2.

[0054] In some embodiments in which the encoder 100 is linear, the fourth composite position information has a fourth composite pitch PS4. The third composite pitch PS3 is (M+1) / M times the second composite pitch PS2, so that the fourth composite pitch PS4 is (M+1) times the second composite pitch PS2 or M times the third composite pitch PS3, where M is an integer greater than 2.

[0055] For example, under the condition that M is 32, the first pitch P1 is 64 μm, the second pitch P2 is 62 μm, the third pitch P3 is 2,048 μm, and the fourth pitch P4 is 2,046 μm, the signal processing unit 120 can calculate first composite position information in which the first composite pitch PS1 is 1,984 μm, second composite position information in which the second composite pitch PS2 is 63,488 μm, third composite position information in which the third composite pitch PS3 is 65,472 μm, and fourth composite position information in which the fourth composite pitch PS4 is 2,095,104 μm.

[0056] For example, under the condition that M is 64, the first pitch P1 is 64 μm, the second pitch P2 is 63 μm, the third pitch P3 is 4,096 μm, and the fourth pitch P4 is 4,095 μm, the signal processing unit 120 can calculate first composite position information where the first composite pitch PS1 is 4,032 μm, second composite position information where the second composite pitch PS2 is 258,048 μm, third composite position information where the third composite pitch PS3 is 262,080 μm, and fourth composite position information where the fourth composite pitch PS4 is 16,773,120 μm.

[0057] It should be noted that the fourth combined position information analyzed by the signal processing unit 120 can be the initial absolute position information. The second combined position information or the third combined position information analyzed by the signal processing unit 120 can be the low-accuracy position information. The third detected position information, the fourth detected position information, or the first combined position information analyzed by the signal processing unit 120 can be the medium-accuracy position information. The first detected position information or the second detected position information can be the high-accuracy position information.

[0058] Please refer to FIG. 15, which is a schematic diagram of obtaining position information using a position detection method of the encoder 100 according to an embodiment of the present disclosure. As shown in FIG. 15, in this embodiment, the signal processing unit 120 is further configured to analyze the first position a using the fourth combined position information (i.e., initial absolute position information). The signal processing unit 120 is further configured to associate the first position a with the second combined position information or the third combined position information (i.e., low-precision position information) and analyze the second position b, which is shown in the figure as the second periodic position. The signal processing unit 120 is further configured to associate the second position b with the third detected position information, the fourth detected position information, or the first combined position information (i.e., medium-precision position information) and analyze the third position c, which is shown in the figure as the fifth periodic position. The signal processing unit 120 is further configured to associate the third position c with the first detected position information or the second detected position information (i.e., high-precision position information) and analyze the fourth position d, which is a highly precise absolute position. In this gradual position analysis step, the initial absolute position is associated with a low-precision incremental position, the low-precision incremental position is associated with a medium-precision incremental position, and the medium-precision incremental position is associated with a high-precision incremental position, and the analyzed position information is a high-precision absolute position. This allows the encoder 100 of this embodiment to achieve high-precision absolute position detection.

[0059] As can be clearly seen 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 four detection elements. Two of the detection elements are positioned to detect one of the pattern areas, and the other two detection elements 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 assembly margin of the mechanism. Furthermore, because the light-receiving elements of each detection element are arranged out of phase with each other, the optical sensor assembly has higher resistance to environmental contamination 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 four sets of incremental position signals and a vernier method, thereby achieving high-precision absolute position detection.

[0060] Although the present disclosure has been disclosed in the embodiments as described above, the above-described embodiments do not limit the present disclosure, and any person 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 is as defined by the claims attached below. [Explanation of symbols]

[0061] 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-, A4+, A4-, B4+, B4-: Photodetector 112b: Second detection unit 112c: Third detection unit 112d: Fourth detection unit 113: Light source 120: Signal processing unit a: 1st position b: 2nd position c: 3rd position d: 4th position C1, C2: row D1: 1st direction D2:Second direction G1: First pattern G2: Second pattern P1: First pitch P1', P2': pitch P2: Second pitch P3: Third pitch P4: 4th 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 SA4+, SA4-, SB4+, SB4-: 4th detection position signal

Claims

1. 1. An optical sensor assembly comprising: a scale including: a first pattern area including a plurality of first patterns periodically arranged in a first direction and a second direction; and a second pattern area including a plurality of second patterns periodically arranged in the first direction and the 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, a third detection unit arranged to detect a change in the first pattern area in the second direction, and a fourth detection unit arranged to detect a change in the second pattern area in the second direction, and 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 first patterns arranged along the first direction are gradually shifted in the second direction.

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

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

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

6. 6. The optical sensor assembly of claim 5, 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 N times the pitch distance along the first direction are progressively offset by one of the different pitch distances in the second direction, where N is an integer greater than 2.

7. 7. The optical sensor assembly of claim 6, wherein after the sensor moves N times the pitch distance in the first direction relative to the scale, the second sensing portion generates N periodic signals and the fourth sensing portion generates one periodic signal.

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

9. 1. An encoder comprising: 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 direction; and a second pattern area including a plurality of second patterns periodically arranged in the first direction and the second direction; a sensor arranged to move relative to the scale in the first direction, the sensor including: a first detection unit arranged to detect a change in the first pattern area in the first direction and correspondingly generating a first detected position signal; a second detection unit arranged to detect a change in the second pattern area in the first direction and correspondingly generating a second detected position signal; a third detection unit arranged to detect a change in the first pattern area in the second direction and correspondingly generating a third detected position signal; and a fourth detection unit arranged to detect a change in the second pattern area in the second direction and correspondingly generating a fourth detected position signal; Including, The signal processing unit calculating first detected position information, second detected position information, third detected position information, and fourth detected position information from the first detected position signal, the second detected position signal, the third detected position signal, and the fourth 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; calculating third combined position information using the fourth detected position information and the first combined position information; calculating fourth combined position information from the second combined position information and the third combined position information; an encoder connected to the sensor and arranged to:

10. The encoder of claim 9 , wherein the first patterns arranged along the first direction are gradually shifted in the second direction.

11. 11. The encoder of claim 10, wherein the first patterns are arranged in a plurality of rows, the rows having a pitch in the first direction, the first patterns in each row having a different pitch in the second direction, and the rows passing M times the pitch distance along the first direction are progressively offset by one of the different pitch distances in the second direction, where M is an integer greater than 2.

12. 12. The encoder of claim 11, wherein the first sensing unit generates M periodic signals and the third sensing unit generates one periodic signal after the sensor moves M times the pitch distance in the first direction relative to the scale.

13. The encoder of claim 9 , wherein the second patterns arranged along the first direction are gradually shifted in the second direction.

14. 14. The encoder of claim 13, 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 N times the pitch distance along the first direction are progressively offset by one of the different pitch distances in the second direction, where N is an integer greater than 2.

15. 15. The encoder of claim 14, wherein the second sensing portion generates N periodic signals and the fourth sensing portion generates one periodic signal after the sensor moves N times the pitch distance in the first direction relative to the scale.

16. The encoder according to claim 9 , wherein the light receiving elements of the first detection unit, the second detection unit, the third detection unit and the fourth detection unit are arranged with a phase shift.

17. The encoder according to any one of claims 9 to 15, wherein the signal processing unit is configured to calculate the first composite position information based on a Vernier method using the first detected position information and the second detected position information.

18. The encoder according to any one of claims 9 to 15, 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.

19. The encoder according to claim 9 , wherein the signal processing unit is configured to calculate the third composite position information based on the fourth detected position information and the first composite position information based on a Vernier method.

20. The encoder according to any one of claims 9 to 15, wherein the signal processing unit is configured to calculate the fourth composite position information based on the second composite position information and the third composite position information according to a Vernier method.

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