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 an optical sensor assembly and an encoder. Background Art

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

[0003] In the known art, optical encoders use gray code or M code to obtain absolute position information, and their main architecture includes an optical transmitter, an optical receiver, a code disc, and a processing circuit. In a reflective optical encoder, the optical transmitter and the optical receiver are disposed on the same side relative to the code disc, and the required signal output is obtained by appropriately designing the pattern on the code disc. Summary of Invention Problem to be Solved by Invention

[0004] However, known encoder architectures and encoding methods are extremely sensitive to position deviation, so extremely accurate assembly alignment is required for encoders. As the demand for encoder accuracy increases, the area of the detection portion of the corresponding optical receiver is also greatly reduced, and external environmental contamination such as oil stains, dirt and fine particles has a serious impact on the detection of absolute position signals.

[0005] Therefore, in order to improve the problems and drawbacks in the known art, realize high-precision absolute position detection, have higher resistance to environmental pollution, and improve the stability of the encoder, how to develop a novel optical sensor assembly different from conventional ones and an encoder applying the same is actually an important issue in the current technical field. Means for Solving the Problem

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

[0007] To achieve the above objective, according to one embodiment of the present disclosure, an optical sensor assembly comprises a scale, a sensor, and a light source. The scale q includes a first pattern region comprising a plurality of first patterns periodically arranged in a first and a second direction, and a second pattern region comprising a plurality of second patterns periodically arranged in a first and a second direction. The sensor includes a first sensing unit arranged to detect changes in the first pattern region in a first direction, a second sensing unit arranged to detect changes in the second pattern region in a first direction, a third sensing unit arranged to detect changes in the first pattern region in a second direction, and a fourth sensing unit arranged to detect changes in the second pattern region in a second direction, and is arranged to move relative to the scale in a first direction. The light source is arranged to emit light toward the scale.

[0008] In one or more embodiments of the present disclosure, a first pattern arranged along a first direction is progressively shifted in a second direction.

[0009] In one or more embodiments of the present disclosure, the first pattern is arranged in multiple 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 row, after passing M times the distance of the pitch along the first direction, is progressively shifted in the second direction by the distance of one of the other pitches, where M is an integer greater than 2.

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

[0011] In one or more embodiments of the present disclosure, a second pattern arranged along a first direction is progressively shifted in the second direction.

[0012] In one or more embodiments of the present disclosure, the second pattern is arranged in multiple rows, the rows having a pitch in a first direction, the second pattern in each row having a different pitch in a second direction, and the row, after passing N times the distance of the pitch along the first direction, is progressively shifted in the second direction by the distance of one of the other pitches, 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 a first direction relative to the scale, the second detection unit generates N periodic signals and the fourth detection unit generates one periodic signal.

[0014] In one or more embodiments of the present disclosure, 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 difference.

[0015] To achieve the above objective, according to one embodiment of the present disclosure, in one or more embodiments of the present disclosure, the encoder comprises an optical sensor assembly and a signal processing unit. The optical sensor assembly includes a scale and a sensor, the scale including a first pattern region including a plurality of first patterns arranged periodically in a first and second direction, and a second pattern region including a plurality of second patterns arranged periodically in a first and second direction, the sensor including a first detection unit arranged to detect changes in the first pattern region in a first direction and correspondingly generating a first detection position signal, a second detection unit arranged to detect changes in the second pattern region in a first direction and correspondingly generating a second detection position signal, a third detection unit arranged to detect changes in the first pattern region in a second direction and correspondingly generating a third detection position signal, and a fourth detection unit arranged to detect changes in the second pattern region in a second direction and correspondingly generating a fourth detection position signal, and the sensor is arranged to move relative to the scale in a first direction. The signal processing unit is arranged and connected to the sensor to calculate first detection position information, second detection position information, third detection position information, and fourth detection position information from the first detection position signal, second detection position signal, third detection position signal, and fourth detection position signal, respectively; to calculate first combined position information from the first detection position information and second detection position information; to calculate second combined position information from the third detection position information and first combined position information; to calculate third combined position information from the fourth detection position information and first combined position information; and to calculate fourth combined position information from the second combined position information and third combined position information.

[0016] In one or more embodiments of the present disclosure, a first pattern arranged along a first direction is progressively shifted in a second direction.

[0017] In one or more embodiments of the present disclosure, the first pattern is arranged in multiple 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 row, after passing M times the distance of the pitch along the first direction, is progressively shifted in the second direction by the distance of one of the other pitches, where M is an integer greater than 2.

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

[0019] In one or more embodiments of the present disclosure, a second pattern arranged along a first direction is progressively shifted in the second direction.

[0020] In one or more embodiments of the present disclosure, the second pattern is arranged in multiple rows, the rows having a pitch in a first direction, the second pattern in each row having a different pitch in a second direction, and the row, after N times the distance of the pitch along the first direction, is progressively shifted in the second direction by the distance of one other pitch, 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 a first direction relative to the scale, the second detection unit generates N periodic signals and the fourth detection unit generates one periodic signal.

[0022] In one or more embodiments of the present disclosure, 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 difference.

[0023] In one or more embodiments of the present disclosure, the signal processing unit is arranged to calculate a first composite position information based on a vernier scheme using first detected position information and second detected position information.

[0024] In one or more embodiments of the present disclosure, the signal processing unit is arranged to calculate second combined position information based on a vernier method from third detected position information and first combined position information.

[0025] The signal processing unit is arranged to calculate third combined position information based on a vernier method from fourth detected position information and first combined position information.

[0026] The signal processing unit is arranged to calculate fourth combined position information based on a vernier method from the second combined position information and the third combined position information.

Effects of the Invention

[0027] As described above, in the optical sensor assembly of the present disclosure, the scale includes two pattern regions, and the sensor includes four detection units. Two of the detection units are arranged to detect one of the pattern regions, and the other two detection units are arranged to detect the other pattern region. Since the scale includes only two pattern regions, the optical sensor assembly only requires a small detection area, thereby increasing the assembly margin of the mechanism. In addition, the light-receiving elements of each detection unit are arranged with a phase shift, that is, the light-receiving elements of each detection unit are arranged with a phase difference therebetween, so that the encoder has higher resistance to environmental pollution and a better assembly positioning margin, thereby improving the stability of the encoder. Furthermore, since the encoding and decoding of an encoder applying this optical sensor assembly uses four sets of incremental position signals and a vernier method, high-precision absolute position detection can be achieved.

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

Brief Description of Drawings

[0029] To make the above and other purposes, features, advantages, and examples of this disclosure clearer and easier to understand, the accompanying drawings are described below. [Figure 1] This is a partial perspective view showing an encoder according to one embodiment of the present disclosure. [Figure 2] This is a partial schematic diagram showing the scale in Figure 1. [Figure 3] Figure 1 is a schematic diagram showing the sensor, light source, and signal processing unit. [Figure 4] This is a partial schematic diagram showing a first pattern region of scale according to one embodiment of the present disclosure. [Figure 5] This is a partial schematic diagram showing a second pattern region of scale according to one embodiment of the present disclosure. [Figure 6] This is a partial schematic diagram showing a first detection unit of a sensor according to one embodiment of the present disclosure. [Figure 7] This is a partial schematic diagram showing a second detection unit of a sensor according to one embodiment of the present disclosure. [Figure 8] This is a partial schematic diagram showing a third detection unit of a sensor according to one embodiment of the present disclosure. [Figure 9] This is a partial schematic diagram showing a fourth detection unit of a sensor according to one embodiment of the present disclosure. [Figure 10] This is a schematic diagram showing the first detection position signal obtained by detecting the first pattern region using the first detection unit and the third detection unit, respectively. [Figure 11] These are schematic diagrams showing the first detection position information and the third detection position information calculated from the first detection position signal and the third detection position signal, respectively. [Figure 12] This is a schematic diagram showing the second detection position signal and the fourth detection position signal obtained by detecting the second pattern region using the second detection unit and the fourth detection unit, respectively. [Figure 13] These are schematic diagrams showing the second detection position information and the fourth detection position information calculated from the second detection position signal and the fourth detection position signal, respectively. [Figure 14A] This is a schematic diagram showing a 16-period signal. [Figure 14B]This is a schematic diagram showing a 15-period signal. [Figure 14C] This is a schematic diagram showing the difference signal between a 16-period signal and a 15-period signal. [Figure 14D] This is a schematic diagram showing the difference signal in Figure 14C in unsigned 10-bit data format. [Figure 15] This is a schematic diagram showing how position information is acquired by an encoder position detection method according to one embodiment of the present disclosure. [Modes for carrying out the invention]

[0030] Several embodiments of this disclosure are disclosed below with reference to drawings, and many practical details are described in conjunction with the following description for clarity. However, it should be understood that these practical details are not applicable to limit this disclosure. In other words, these practical details are not necessary for some embodiments of this disclosure. Furthermore, for the sake of simplicity in the drawings, some conventional structures and elements are briefly illustrated in the drawings.

[0031] Refer to Figure 1, a partial perspective view of an encoder 100 according to one embodiment of the present disclosure. As shown in Figure 1, in this embodiment, the encoder 100 comprises an optical sensor assembly 110. The optical sensor assembly 110 comprises a scale 111, a sensor 112, and a light source 113. The scale 111 and the sensor 112 are positioned opposite each other and are displaceable relative to each other. For example, the scale 111 can be moved or rotated linearly relative to the sensor 112. The light source 113 is positioned 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 rays 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 region 111a and a second pattern region 111b. The first pattern region 111a and the second pattern region 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 positioned 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 positioned to detect changes in the first pattern region 111a in the first direction D1. The second detection unit 112b is positioned to detect changes in the first direction D1 of the second pattern region 111b. The third detection unit 112c is positioned to detect changes in the second direction D2 of the first pattern region 111a. The fourth detection unit 112d is positioned to detect changes in the second direction D2 of the second pattern region 111b.

[0033] 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.

[0034] Please refer to Figure 4, 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 Figure 4, in this embodiment, the first pattern region 111a of the scale 111 includes a plurality of first patterns G1 arranged periodically in a first direction D1 and a second direction D2. Specifically, the first patterns G1 are arranged in multiple rows C1. These rows C1 have a first pitch P1 in the first direction D1. The first patterns G1 in each row C1 have another pitch P1' in the second direction D2. In other words, the first patterns G1 of the first pattern region 111a constitute a two-dimensional pattern.

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

[0036] In particular, the first pattern G1, which is arranged along the first direction D1, is progressively shifted in the second direction D2. Specifically, as shown in Figure 4, these rows C1, which have traveled M times the distance of the first pitch P1 along the first direction D1, are progressively shifted by a distance of one pitch P1' in the second direction D2, 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 distance of the first pitch P1. Correspondingly, after the sensor 112 has moved 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 Figure 4, M is 12 (i.e., these rows C1, having traveled 12 times the distance of the first pitch P1 along the first direction D1, are progressively shifted by a distance of one pitch P1' in the second direction D2), but the disclosure is not limited thereto.

[0038] Please refer to Figure 5, a partial schematic diagram showing a second pattern region 111b of a scale 111 according to one embodiment of the present disclosure. As shown in Figure 5, in this embodiment, the second pattern region 111b of the scale 111 includes a plurality of second patterns G2 arranged periodically in a first direction D1 and a second direction D2. Specifically, the second patterns G2 are arranged in multiple rows C2. These rows C2 have a second pitch P2 in the first direction D1. The second patterns G2 in each row C2 have another pitch P2' in the second direction D2. In other words, the second patterns G2 of the second pattern region 111b constitute a two-dimensional pattern.

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

[0040] In particular, the second pattern G2, which is arranged along the first direction D1, is progressively shifted in the second direction D2. Specifically, as shown in Figure 5, these rows C2, which have traveled N times the distance of the second pitch P2 along the first direction D1, are progressively 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 fourth pitch P4 in the first direction D1, and the fourth pitch P4 is N times the distance of the second pitch P2. Correspondingly, after the sensor 112 has moved 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 the above structural arrangement, while the sensor 112 and the scale 111 move relative to each other in the first direction D1, the sensor 112 can simultaneously detect the first pattern region 111a using the first detection unit 112a and the third detection unit 112c, and simultaneously detect the second pattern region 111b using the second detection unit 112b and the fourth detection unit 112d. Since the scale 111 contains only two pattern regions, the optical sensor assembly 110 requires only 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 Figure 5, N is 12 (i.e., these rows C2, having traveled 12 times the distance of the second pitch P2 along the first direction D1, are progressively shifted by a distance of one pitch P2' in the second direction D2), but the disclosure is not limited thereto.

[0043] Please refer to Figures 6, 7, 8, and 9. Figure 6 is a partial schematic diagram showing the first detection unit 112a of the sensor 112 according to one embodiment of the present disclosure. Figure 7 is a partial schematic diagram showing the second detection unit 112b of the sensor 112 according to one embodiment of the present disclosure. Figure 8 is a partial schematic diagram showing the third detection unit 112c of the sensor 112 according to one embodiment of the present disclosure. Figure 9 is a partial schematic diagram showing the fourth detection unit 112d of the 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- arranged with a phase difference. The second detection unit 112b includes a plurality of light-receiving elements A2+, B2+, A2-, and B2- arranged with a phase difference. The third detection unit 112c includes a plurality of light-receiving elements A3+, B3+, A3-, and B3- arranged with a phase difference. The fourth detection unit 112d includes a plurality of photodetectors A4+, B4+, A4-, and B4- that are arranged with a phase difference. Specifically, the photodetectors A1+, B1+, A1-, and B1- of the first detection unit 112a are arranged with a phase difference periodically in the first direction D1, that is, the photodetectors A1+, B1+, A1-, and B1- are arranged alternately in multiple cycles. The photodetectors A2+, B2+, A2-, and B2- of the second detection unit 112b are arranged with a phase difference periodically in the first direction D1, that is, the photodetectors A2+, B2+, A2-, and B2- are arranged alternately in multiple cycles. The light-receiving elements A3+, B3+, A3-, and B3- of the third detection unit 112c are arranged in the second direction D2 with a periodic phase shift, that is, the light-receiving elements A3+, B3+, A3-, and B3- are arranged alternately in multiple cycles. The light-receiving elements A4+, B4+, A4-, and B4- of the fourth detection unit 112d are arranged in the second direction D2 with a periodic phase shift, that is, the light-receiving elements A4+, B4+, A4-, and B4- are arranged alternately in multiple cycles. 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 are given high resistance to environmental pollution and a better assembly positioning margin, thereby increasing the stability of the encoder 100.

[0044] Please refer to Figure 10, a schematic diagram showing the first detection position signal and the third detection position signal obtained by detecting the first pattern region 111a using the first detection unit 112a and the third detection unit 112c, respectively. As shown in Figure 10, in this embodiment, the first detection unit 112a generates a first detection position signal in correspondence after detecting a change in the first direction D1 of the first pattern region 111a. Specifically, the photoreceiving elements A1+, B1+, A1-, and B1- of the first detection unit 112a generate the first detection position signals SA1+, SB1+, SA1-, and SB1-, respectively. The third detection unit 112c generates a third detection position signal in correspondence after detecting a change in the second direction D2 of the first pattern region 111a. More specifically, the light-receiving elements A3+, B3+, A3-, and B3- of the third detection unit 112c generate the third detection position signals SA3+, SB3+, SA3-, and SB3-, respectively.

[0045] As shown in Figure 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 detection position signals SA1+, SB1+, SA1-, SB1- generated by the first detection unit 112a and the third detection position signals SA3+, SB3+, SA3-, SB3- generated by the third detection unit 112c. In this embodiment, the signal processing unit 120 is integrated with the sensor 112, but the disclosure is not limited thereto. In actual applications, the signal processing unit 120 and the sensor 112 may not be integrated and may be connected via additional components.

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

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

[0048] Please refer to Figure 13, a schematic diagram showing the second detection position information and the fourth detection position information calculated from the second detection position signal and the fourth detection position signal, respectively. In this embodiment, the signal processing unit 120 is further configured to calculate the second detection position information (shown in Figure 13) from the second detection position signals SA2+, SB2+, SA2-, and SB2- (shown in Figure 12). For example, the second detection position information can be calculated using an inverse tangent function. The second detection position information also has a second pitch P2. Furthermore, the signal processing unit 120 is further configured to calculate the fourth detection position information (shown in Figure 13) from the fourth detection position signals SA4+, SB4+, SA4-, and SB4- (shown in Figure 12). For example, the fourth detection position information can be calculated using an inverse tangent function. The fourth detection position information also has a fourth pitch P4.

[0049] In this embodiment, the signal processing unit 120 is configured to further calculate a first combined position information from the first detection position information and the second detection position information, a second combined position information from the third detection position information and the first combined position information, a third combined position information from the fourth detection position information and the first combined position information, and a fourth combined position information from 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 based on the Vernier method from the first detection position information and the second detection position information. The signal processing unit 120 is configured to further calculate the second combined position information based on the Vernier method from the third detection position information and the first combined position information. The signal processing unit 120 is configured to further calculate the third combined position information based on the Vernier method from the fourth detection position information and the first combined position information. The signal processing unit 120 is configured to further calculate the fourth combined position information based on the Vernier method from the second combined position information and the third combined position information. The principle of the vernier system is briefly explained below.

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

[0051] In some embodiments where the encoder 100 is linear, N is equal to M+1. The first composite position information has a first composite pitch PS1. Since the second pitch P2 of the second detected position information is (M-1) / M times the first pitch P1 of the first detected position information, the first composite pitch PS1 is (M-1) times the first pitch P1 or M times the second pitch P2. M is an integer greater than 2.

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

[0053] In some embodiments where 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 where the encoder 100 is linear, the fourth composite position information has a fourth composite pitch PS4. Since the third composite pitch PS3 is (M+1) / M times the second composite pitch PS2, 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 conditions 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 combined position information with a first combined pitch PS1 of 1,984 μm, second combined position information with a second combined pitch PS2 of 63,488 μm, third combined position information with a third combined pitch PS3 of 65,472 μm, and fourth combined position information with a fourth combined pitch PS4 of 2,095,104 μm.

[0056] For example, under the conditions 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 combined position information with a first combined pitch PS1 of 4,032 μm, second combined position information with a second combined pitch PS2 of 258,048 μm, third combined position information with a third combined pitch PS3 of 262,080 μm, and fourth combined position information with a fourth combined pitch PS4 of 16,773,120 μm.

[0057] It should be explained that the fourth composite position information analyzed by the signal processing unit 120 can be used as the initial absolute position information. The second composite position information or the third composite position information analyzed by the signal processing unit 120 can be used as low-precision position information. The third detection position information, the fourth detection position information, or the first composite position information analyzed by the signal processing unit 120 can be used as medium-precision position information. The first detection position information or the second detection position information can be used as high-precision position information.

[0058] Please refer to Figure 15, a schematic diagram showing how position information is acquired by a position detection method of encoder 100 according to one embodiment of the present disclosure. As shown in Figure 15, in this embodiment, the signal processing unit 120 is further configured to analyze the first position a using a fourth composite position information (i.e., initial absolute position information). The signal processing unit 120 is further configured to associate the first position a with a second composite position information or a third composite position information (i.e., low-precision position information) and to analyze the second position b, which is the second periodic position. The signal processing unit 120 is further configured to associate the second position b with a third detected position information, a fourth detected position information, or a first composite position information (i.e., medium-precision position information) and to analyze the third position c, which is the fifth periodic position. The signal processing unit 120 is further configured to associate the third position c with a first detected position information or a second detected position information (i.e., high-precision position information) and to analyze the fourth position d, which is a high-precision absolute position. In this progressive position analysis step, the initial absolute position is mapped to a low-precision incremental position, then to a medium-precision incremental position, and finally to a high-precision incremental position. The position information analyzed is a high-resolution absolute position. As a result, the encoder 100 of this embodiment can achieve high-resolution absolute position detection.

[0059] As can be clearly seen from the detailed description of the specific embodiments of this disclosure above, in the optical sensor assembly of this disclosure, the scale includes two pattern regions, and the sensor includes four sensing units. Two of the sensing units are arranged to detect one of the pattern regions, and the other two sensing units are arranged to detect the other pattern region. Because the scale includes only two pattern regions, the optical sensor assembly requires only a small sensing area, thereby increasing the assembly margin of the mechanism. Furthermore, because the photodetectors of each sensing unit are aligned with a phase difference, they have higher resistance to environmental pollution and better assembly positioning margins, thereby increasing the stability of the encoder. In addition, the encoding and decoding of the encoder using this optical sensor assembly utilizes four sets of incremental position signals and a vernier method, enabling high-definition absolute position detection.

[0060] Although the present disclosure is disclosed in embodiments as described above, these embodiments are not limiting, and any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure. The scope of protection of the present disclosure is therefore limited to that defined by the claims appended below. [Explanation of Symbols]

[0061] 100: Encoder 110: Optical Sensor Assembly 111: Scale 111a: First pattern region 111b: Second pattern region 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: Pattern 1 G2: Pattern 2 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-: Fourth detection position signal

Claims

1. An optical sensor assembly, A scale comprising: a first pattern region including a plurality of first patterns periodically arranged in a first and second direction; and a second pattern region including a plurality of second patterns periodically arranged in the first and second direction; A sensor comprising: a first detection unit arranged to detect changes in the first direction of the first pattern region; a second detection unit arranged to detect changes in the first direction of the second pattern region; a third detection unit arranged to detect changes in the second direction of the first pattern region; and a fourth detection unit arranged to detect changes in the second direction of the second pattern region, wherein the sensor is arranged to move relative to the scale in the first direction, A light source arranged to emit light toward the aforementioned scale, Equipped with, The first pattern, which is arranged along the first direction, is gradually shifted in the second direction. Optical sensor assembly.

2. The optical sensor assembly according to claim 1, wherein the first pattern is arranged in multiple rows, the rows have a pitch in a first direction, the first pattern in each row has a different pitch in a second direction, and the row that has passed M times the distance of the pitch along the first direction is progressively shifted in the second direction by the distance of one of the other pitches, where M is an integer greater than 2.

3. The optical sensor assembly according to claim 2, wherein after the sensor moves a distance of M times the pitch distance in the first direction relative to the scale, the first detection unit generates M periodic signals and the third detection unit generates one periodic signal.

4. The optical sensor assembly according to claim 1, wherein the second pattern arranged along the first direction is gradually shifted in the second direction.

5. The optical sensor assembly according to claim 4, wherein the second pattern is arranged in multiple rows, the rows have a pitch in the first direction, the second pattern in each row has a different pitch in the second direction, and the row that has passed N times the distance of the pitch along the first direction is progressively shifted in the second direction by the distance of one of the other pitches, where N is an integer greater than 2.

6. The optical sensor assembly according to claim 5, wherein after the sensor moves N times the pitch distance in the first direction relative to the scale, the second detection unit generates N periodic signals and the fourth detection unit generates one periodic signal.

7. The optical sensor assembly according to any one of claims 1 to 6, 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 difference.

8. It is an encoder, It comprises an optical sensor assembly and a signal processing unit, The optical sensor assembly is A scale comprising: a first pattern region including a plurality of first patterns periodically arranged in a first and second direction; and a second pattern region including a plurality of second patterns periodically arranged in the first and second direction; A sensor comprising: a first detection unit arranged to detect changes in the first direction of the first pattern region and correspondingly generate a first detection position signal; a second detection unit arranged to detect changes in the first direction of the second pattern region and correspondingly generate a second detection position signal; a third detection unit arranged to detect changes in the second direction of the first pattern region and correspondingly generate a third detection position signal; and a fourth detection unit arranged to detect changes in the second direction of the second pattern region and correspondingly generate a fourth detection position signal, wherein the sensor is arranged to move relative to the scale in the first direction, Includes, The aforementioned signal processing unit is The first detection position signal, the second detection position signal, the third detection position signal, and the fourth detection position signal are used to calculate the first detection position information, the second detection position information, the third detection position information, and the fourth detection position information, respectively. The first combined position information is calculated using the first detection position information and the second detection position information. The second combined position information is calculated using the third detection position information and the first combined position information, The third combined position information is calculated using the fourth detection position information and the first combined position information, The fourth composite position information is calculated using the second composite position information and the third composite position information, An encoder is positioned to perform the following actions and is connected to the sensor.

9. The encoder according to claim 8, wherein the first pattern arranged along the first direction is gradually shifted in the second direction.

10. The encoder according to claim 9, wherein the first pattern is arranged in multiple rows, the rows have a pitch in a first direction, the first pattern in each row has a different pitch in a second direction, and the row that has passed M times the distance of the pitch along the first direction is progressively shifted in the second direction by the distance of one of the other pitches, where M is an integer greater than 2.

11. The encoder according to claim 10, wherein after the sensor moves by M times the pitch distance in the first direction relative to the scale, the first detection unit generates M periodic signals and the third detection unit generates one periodic signal.

12. The encoder according to claim 8, wherein the second pattern arranged along the first direction is gradually shifted in the second direction.

13. The encoder according to claim 12, wherein the second pattern is arranged in multiple rows, each row has a pitch in the first direction, each row of the second pattern has a different pitch in the second direction, and each row that has traveled N times the distance of the pitch along the first direction is progressively shifted in the second direction by the distance of one of the other pitches, where N is an integer greater than 2.

14. The encoder according to claim 13, wherein after the sensor moves N times the pitch distance in the first direction relative to the scale, the second detection unit generates N periodic signals and the fourth detection unit generates one periodic signal.

15. The encoder according to any one of claims 8 to 14, 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 difference.

16. The encoder according to any one of claims 8 to 14, wherein the signal processing unit is arranged to calculate the first composite position information based on the vernier method using the first detected position information and the second detected position information.

17. The encoder according to any one of claims 8 to 14, wherein the signal processing unit is arranged to calculate the second composite position information based on the vernier method using the third detection position information and the first composite position information.

18. The encoder according to any one of claims 8 to 14, wherein the signal processing unit is arranged to calculate the third composite position information based on the vernier method using the fourth detection position information and the first composite position information.

19. The encoder according to any one of claims 8 to 14, wherein the signal processing unit is arranged to calculate the fourth composite position information based on the vernier method using the second composite position information and the third composite position information.

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