Encoder and mounting method

Abstract

An encoder (10) comprises: an emission unit (40) that emits light; a rotary plate (20) that rotates and that has an annular region (26) which is provided so as to surround a rotational axis (A) of the rotary plate (20) and which reflects light emitted by the emission unit (40); and a light reception unit (50) that receives light emitted by the emission unit (40) and arrived via the annular region (26). The light reception unit (50) has a first set having a first light reception region (55) and a second light reception region (56) arranged side by side in a first direction (E) intersecting the rotational direction (C) of the rotary plate (20) and a second set having a third light reception region (57) and a fourth light reception region (58) arranged side by side in a second direction (F) intersecting the rotational direction (C) and provided side by side with the first set in the rotational direction (C).

Description

[Technical Field]

[0001] This disclosure relates to an encoder and a mounting method. [Background technology]

[0002] Conventionally, encoders for detecting the rotation of an object to be detected, such as a motor shaft, are known. For example, such an encoder comprises a rotating plate that rotates together with the object to be detected, and a member for detecting the eccentricity of the rotating plate relative to the object to be detected. For example, Patent Document 1 discloses an angular velocity detection device in which a sensor member is placed at a position opposite to the rotation center of the shaft, angular velocity information obtained from the sensor member is input to a control device for calculation processing, error components of the mounting position of the disc are removed, only the true rotational angular velocity component is obtained, and a drive pulse is output to the drive motor for the photoreceptor drum so as not to cause rotational fluctuations. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 7-140844 [Overview of the project] [Problems that the invention aims to solve]

[0004] However, the angular velocity detection device described in Patent Document 1 has the problem of not being able to accurately detect the eccentricity of the rotating plate relative to the object being detected.

[0005] This disclosure is made to solve these problems and aims to provide an encoder, etc., that can accurately detect the eccentricity of a rotating plate relative to the object to be detected. [Means for solving the problem]

[0006] An encoder according to one aspect of the present disclosure comprises an emission unit that emits light, a rotating plate that rotates and is provided so as to surround the rotation axis of the rotating plate and has an annular region that reflects or transmits light emitted from the emission unit, and a light receiving unit that receives light emitted from the emission unit and that has passed through the annular region, wherein the light receiving unit has a first set having a first light receiving region and a second light receiving region arranged in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light receiving region and a fourth light receiving region arranged in a second direction intersecting the rotation direction and provided alongside the first set in the rotation direction.

[0007] Furthermore, an attachment method according to one aspect of the present disclosure is an attachment method for attaching an encoder to a detection target, wherein the encoder comprises an emitting unit that emits light, a rotating plate that rotates and is provided so as to surround the rotation axis of the rotating plate and has an annular region that reflects or transmits light emitted from the emitting unit, and a light receiving unit that receives light emitted from the emitting unit and that has passed through the annular region, wherein the light receiving unit comprises a first set having a first light receiving region and a second light receiving region arranged in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light receiving region and a fourth light receiving region arranged in a second direction intersecting the rotation direction and provided alongside the first set in the rotation direction, and the signal value corresponding to the light received by the first light receiving region is defined as A1, and The device further includes an output unit that outputs a signal indicating the following X value and Y value, where A2 is the signal value corresponding to the light received by the second light-receiving region, B1 is the signal value corresponding to the light received by the third light-receiving region, and B2 is the signal value corresponding to the light received by the fourth light-receiving region, and X = (A1 + B2) - (B1 + A2), Y = (A1 + B1) - (A2 + B2). The device includes the steps of attaching the rotating plate to the object to be detected, and after attaching the rotating plate to the object to be detected, causing the output unit to output a signal indicating the X value and a Y value, wherein the rotating plate is attached to the object to be detected such that the X value indicated by the signal output by the output unit is 0 and the Y value indicated by the signal output by the output unit is 0. [Effects of the Invention]

[0008] According to this disclosure, it is possible to provide an encoder or the like that can accurately detect the eccentricity of a rotating plate relative to the object to be detected. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a perspective view showing an encoder according to the first embodiment. [Figure 2] Figure 2 is a schematic diagram of the rotating plate of the encoder shown in Figure 1, viewed from the axial direction. [Figure 3] Figure 3 is a schematic diagram of the light-emitting and light-receiving sections of the encoder shown in Figure 1, viewed from the axial direction. [Figure 4] Figure 4 is an explanatory diagram illustrating the relationship between the dimensions of the first and second light-receiving regions and the dimensions of the light irradiated onto the first and second light-receiving regions in the encoder shown in Figure 1. [Figure 5] Figure 5 is a block diagram showing the functional configuration of the encoder in Figure 1. [Figure 6] Figure 6 is a schematic diagram showing an example of a state in which the axis of the annular region is eccentric with respect to the axis of rotation. [Figure 7] Figure 7 is a schematic diagram showing an example of the change in the position of light irradiated onto the first, second, third, and fourth light-receiving regions as the rotating plate rotates, in a state where the axis of the annular region is eccentric with respect to the axis of rotation. [Figure 8] Figure 8 is a graph showing an example of a signal output by the output unit as the rotating plate rotates, when the axis of the annular region is eccentric with respect to the axis of rotation. [Figure 9] Figure 9 is a flowchart showing an example of the calculation method used by the calculation unit of the encoder in Figure 1. [Figure 10] Figure 10 is a flowchart showing another example of the calculation method used by the calculation unit of the encoder in Figure 1. [Figure 11] Figure 11 is a schematic diagram of the rotating plate of the encoder according to the second embodiment, viewed from the axial direction. [Figure 12] FIG. 12 is a schematic view of the light emitting portion and the light receiving portion of the encoder in FIG. 11 as viewed from the axial direction. [Figure 13] FIG. 13 is a schematic view of the rotating plate of the encoder according to the third embodiment as viewed from the axial direction. [Figure 14] FIG. 14 is a schematic view of the light emitting portion and the light receiving portion of the encoder in FIG. 13 as viewed from the axial direction. [Figure 15] FIG. 15 is a schematic view of the light emitting portion and the light receiving portion of the encoder according to the fourth embodiment as viewed from the axial direction. [Figure 16] FIG. 16 is an explanatory diagram for explaining the relationship between the dimensions of the first light receiving region and the second light receiving region and the dimensions of the light irradiated on the first light receiving region and the second light receiving region in the encoder according to the fifth embodiment. [Figure 17] FIG. 17 is an explanatory diagram for explaining the relationship between the dimensions of the first light receiving region and the second light receiving region and the dimensions of the light irradiated on the first light receiving region and the second light receiving region in the encoder according to the sixth embodiment. [Figure 18] FIG. 18 is a flowchart showing an example of an attachment method according to the seventh embodiment.

Embodiments for Carrying out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described. Note that each of the embodiments described below shows a specific example of the present disclosure. Therefore, the numerical values, components, arrangement positions and connection forms of the components, as well as the processes and the order of the processes shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, the components not described in the independent claims are described as optional components.

[0011] Also, each figure is a schematic view and is not necessarily drawn precisely. In each figure, substantially the same components are denoted by the same reference numerals, and overlapping descriptions are omitted or simplified.

[0012] Furthermore, in the following embodiments, expressions indicating the relative orientation of two directions, such as parallel and orthogonal, may be used, but these expressions include cases where the orientation is not strictly accurate. For example, when two directions are orthogonal, unless otherwise specified, this means not only that the two directions are perfectly orthogonal, but also that they are substantially orthogonal, that is, that they include a difference of, for example, a few percent.

[0013] (First Embodiment) Figure 1 is a perspective view showing an encoder 10 according to an embodiment. Figure 2 is a schematic diagram of the rotating plate 20 of the encoder 10 in Figure 1 as viewed from the axial direction. Figure 3 is a schematic diagram of the light-emitting section 40 and light-receiving section 50 of the encoder 10 in Figure 1 as viewed from the axial direction. Figure 4 is an explanatory diagram for illustrating the relationship between the dimensions of the first light-receiving area 55 and the second light-receiving area 56 and the dimensions of the light irradiated onto the first light-receiving area 55 and the second light-receiving area 56 in the encoder 10 in Figure 1. The encoder 10 will be described with reference to Figures 1 to 4.

[0014] In Figure 1, to avoid making the drawing too complex, the first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, and the second incremental pattern 25 are omitted from the illustration. Also, in Figure 2, to avoid making the drawing too complex, only half of the rotating plate 20 is shown. Furthermore, in Figure 4, to avoid making the drawing too complex, the emission section 40 and the first and second light-receiving regions 55 and 56 are shown offset in the first direction. The axial direction refers to the direction in which the rotation axis A extends (the Z-axis direction in Figure 1, etc.).

[0015] As shown in Figure 1, the encoder 10 detects the rotation of the object to be detected 1. Specifically, the encoder 10 detects the position (rotational position), rotational direction, amount of rotation, and / or rotational speed of the object to be detected 1. The object to be detected 1 rotates around the rotation axis A as its center of rotation. In this embodiment, the object to be detected 1 is the rotation axis (shaft) of a motor.

[0016] The encoder 10 comprises a rotating plate 20, a substrate 30, an emission unit 40, and a light receiving unit 50.

[0017] As shown in Figures 1 and 2, the rotating plate 20 rotates with the object to be detected 1 around the rotation axis A as the center of rotation. The rotating plate 20 has a body 21, a first absolute pattern 22, a second absolute pattern 23, a first incremental pattern 24, a second incremental pattern 25, and an annular region 26. The first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, and the second incremental pattern 25 are examples of one or more patterns for detecting the rotation angle of the rotating plate 20 (object to be detected 1).

[0018] The main body 21 is plate-shaped with its axial direction as the thickness direction, and is circular when viewed from the axial direction. The main body 21 is attached to one end of the detection target 1 in the axial direction and rotates together with the detection target 1 about the rotation axis A as the center of rotation. The axis of the main body 21 coincides with the axis B of the annular region 26.

[0019] The first absolute pattern 22 is a pattern for detecting the absolute position of the object to be detected 1. The first absolute pattern 22 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the axis of rotation A. The axis of the first absolute pattern 22 coincides with the axis B of the annular region 26. For example, the first absolute pattern 22 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0020] The second absolute pattern 23 is a pattern for detecting the absolute position of the object to be detected 1. The second absolute pattern 23 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the axis of rotation A. The axis of the second absolute pattern 23 coincides with the axis B of the annular region 26. The second absolute pattern 23 is provided further inward than the first absolute pattern 22 in the radial direction centered on the axis B of the annular region 26. For example, the second absolute pattern 23 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0021] The first incremental pattern 24 is a pattern for detecting the relative position of the object to be detected 1. The first incremental pattern 24 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the axis of rotation A. The axis of the first incremental pattern 24 coincides with the axis B of the annular region 26. In the radial direction centered on the axis B of the annular region 26, the first incremental pattern 24 is provided further out than the first absolute pattern 22. For example, the first incremental pattern 24 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0022] The second incremental pattern 25 is a pattern for detecting the relative position of the object to be detected 1. The second incremental pattern 25 is provided on the main surface of the main body 21 on the side of the emission section 40, and is provided in an annular shape so as to surround the axis of rotation A. The axis of the second incremental pattern 25 coincides with the axis B of the annular region 26. In the radial direction centered on the axis B of the annular region 26, the second incremental pattern 25 is provided further inward than the second absolute pattern 23. For example, the second incremental pattern 25 is composed of a reflective section that reflects the light emitted from the emission section 40 toward the light receiving section 50 and a non-reflective section that does not reflect the light emitted from the emission section 40 toward the light receiving section 50, arranged in an annular shape.

[0023] For example, each of the one or more patterns used to detect the rotation angle of the rotating plate 20 may transmit light emitted from the emission unit 40.

[0024] The annular region 26 is an annular region provided so as to surround the axis of rotation A and reflects the light emitted from the emission section 40. The annular region 26 reflects the light emitted from the emission section 40 toward the light receiving section 50. The annular region 26 is provided on the main surface of the main body 21 on the side of the emission section 40. The direction in which the axis B of the annular region 26 extends coincides with the axial direction. Figure 1 illustrates the state in which the axis B of the annular region 26 coincides with the axis of rotation A. For example, the annular region 26 is composed of continuously arranged annular reflective sections that reflect the light emitted from the emission section 40 toward the light receiving section 50.

[0025] As shown in Figure 1, the substrate 30 is positioned opposite the rotating plate 20 in the axial direction. The substrate 30 is plate-shaped with the axial direction being the thickness direction.

[0026] As shown in Figures 1 and 3, the emission unit 40 emits light. Specifically, the emission unit 40 emits light toward the rotating plate 20. More specifically, the emission unit 40 emits light toward the first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, the second incremental pattern 25, and the annular region 26. The emission unit 40 is provided on the main surface of the substrate 30 on the rotating plate 20 side.

[0027] The light-receiving unit 50 receives light that has been emitted from the emission unit 40 and passed through the annular region 26. The light-receiving unit 50 has a first absolute light-receiving region 51, a second absolute light-receiving region 52, a first incremental light-receiving region 53, a second incremental light-receiving region 54, a first set, and a second set. The first absolute light-receiving region 51, the second absolute light-receiving region 52, the first incremental light-receiving region 53, and the second incremental light-receiving region 54 are examples of one or more light-receiving regions that receive light that has been emitted from the emission unit 40 and passed through one or more patterns.

[0028] The first absolute light-receiving region 51 receives light emitted from the emission section 40 and that has passed through the first absolute pattern 22.

[0029] The second absolute light-receiving region 52 receives light emitted from the emission section 40 and that has passed through the second absolute pattern 23.

[0030] The first incremental light-receiving region 53 receives light emitted from the emission section 40 and that has passed through the first incremental pattern 24.

[0031] The second incremental light-receiving region 54 receives light emitted from the emission section 40 and that has passed through the second incremental pattern 25.

[0032] The first set has a first light-receiving region 55 and a second light-receiving region 56 aligned in a first direction E that intersects with the rotation direction C of the rotating plate 20. The second set has a third light-receiving region 57 and a fourth light-receiving region 58 aligned in a second direction F that intersects with the rotation direction C, and is provided alongside the first set in the rotation direction C. In other words, the third light-receiving region 57 and the fourth light-receiving region 58 are provided alongside the first light-receiving region 55 and the second light-receiving region 56 in the rotation direction C.

[0033] In this embodiment, the first set and the second set are arranged with the emission unit 40 in the rotation direction C. That is, the first light-receiving area 55 and the second light-receiving area 56, and the third light-receiving area 57 and the fourth light-receiving area 58 are arranged with the emission unit 40 in the rotation direction C.

[0034] The first direction E and the second direction F are directions parallel to a plane perpendicular to the rotation axis A. In this embodiment, the first direction E and the second direction F are directions parallel to a straight line G perpendicular to the rotation axis A (Y-axis direction), and the first set and the second set are arranged symmetrically with respect to the straight line G as the axis of symmetry. That is, the first light-receiving region 55 and the second light-receiving region 56 are aligned in a direction parallel to the straight line G, the third light-receiving region 57 and the fourth light-receiving region 58 are aligned in a direction parallel to the straight line G, and the first light-receiving region 55 and the second light-receiving region 56 and the third light-receiving region 57 and the fourth light-receiving region 58 are arranged symmetrically with respect to the straight line G as the axis of symmetry.

[0035] In the radial direction centered on the rotation axis A, the first light-receiving region 55 and the third light-receiving region 57 are located at the same position, and the second light-receiving region 56 and the fourth light-receiving region 58 are located at the same position.

[0036] The first light-receiving region 55 and the second light-receiving region 56 are each positioned to receive light emitted from the emission section 40 and passing through the annular region 26 (see H in Figure 3). The third light-receiving region 57 and the fourth light-receiving region 58 are each positioned to receive light emitted from the emission section 40 and passing through the annular region 26 (see H in Figure 3).

[0037] For example, the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 are each light-receiving regions in a light-receiving element. In other words, for example, the light-receiving unit 50 is composed of multiple light-receiving elements.

[0038] As shown in Figure 4, in this embodiment, the emission unit 40 has a point light source, and the dimension between the annular region 26 and the emission unit 40 in the axial direction is h1, the dimension between the annular region 26 and the first light-receiving region 55 and the second light-receiving region 56 in the axial direction is h2, the dimension from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is L, the dimension of the annular region 26 in the first direction E is W1, and the dimension in the first direction E of the light emitted from the point light source and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26 is W2, then W2 = ( (h1+ h2 ) The equation / h1) × W1 is satisfied, and W2 / L < 1 is also satisfied. The same relationship is also satisfied for the third light-receiving region 57 and the fourth light-receiving region 58.

[0039] The dimension L from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is greater than the dimension W2 in the first direction of the light emitted from the emission unit 40 and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26. Also, the dimension from the end of the third light-receiving region 57 opposite to the fourth light-receiving region 58 in the second direction F is greater than the dimension in the second direction F of the light emitted from the emission unit 40 and irradiated onto the third light-receiving region 57 and the fourth light-receiving region 58 via the annular region 26.

[0040] This concludes the explanation of encoder 10.

[0041] Figure 5 is a block diagram showing the functional configuration of the encoder 10 in Figure 1. The functional configuration of the encoder 10 will be explained with reference to Figure 5.

[0042] As shown in Figure 5, the encoder 10 further comprises an output unit 60 and a calculation unit 70. The output unit 60 outputs a signal corresponding to the light received by the light receiving unit 50. Specifically, the output unit 60 outputs a signal corresponding to the light received by the first absolute light receiving area 51, a signal corresponding to the light received by the second absolute light receiving area 52, a signal corresponding to the light received by the first incremental light receiving area 53, a signal corresponding to the light received by the second incremental light receiving area 54, a signal corresponding to the light received by the first light receiving area 55, a signal corresponding to the light received by the second light receiving area 56, a signal corresponding to the light received by the third light receiving area 57, and a signal corresponding to the light received by the fourth light receiving area 58. For example, the output unit 60 outputs a signal corresponding to the intensity of the light received by the light receiving unit 50.

[0043] The output unit 60 outputs a signal indicating the following X value and a signal indicating the Y value, when the signal value corresponding to the light received by the first light-receiving area 55 is set as A1, the signal value corresponding to the light received by the second light-receiving area 56 is set as A2, the signal value corresponding to the light received by the third light-receiving area 57 is set as B1, and the signal value corresponding to the light received by the fourth light-receiving area 58 is set as B2.

[0044] X = (A1 + B2) - (B1 + A2) Y=(A1+B1)-(A2+B2)

[0045] Furthermore, the output unit 60 outputs a signal indicating the following Q values.

[0046] Q = A1 + B1 + A2 + B2

[0047] Furthermore, the output unit 60 outputs a signal indicating the value of X1 and a signal indicating the value of Y1.

[0048] X1 = X / Q Y1 = Y / Q

[0049] The calculation unit 70 calculates the following value of P1, where P is the rotation angle (angle address) of the rotating plate 20 detected based on the light emitted from the emission unit 40 and received by one or more light-receiving regions via one or more patterns, Δr (see Figure 6) is the eccentricity of the axis B of the annular region 26 with respect to the rotation axis A, Φ (see Figure 6) is the eccentric phase of the axis B of the annular region 26 with respect to the rotation axis A, and r (see Figure 6) is the radius of the annular region 26. As described above, in this embodiment, the one or more patterns are the first absolute pattern 22, the second absolute pattern 23, the first incremental pattern 24, and the second incremental pattern 25, and the one or more light-receiving regions are the first absolute light-receiving region 51, the second absolute light-receiving region 52, the first incremental light-receiving region 53, and the second incremental light-receiving region 54.

[0050] P1 = P + tan -1 (Δr × sinΦ / r) Alternatively, P1 = P - tan -1 (Δr × sinΦ / r)

[0051] For example, the calculation unit 70 calculates P1 = P + tan when Φ = 0 to π / 2 and when Φ = 3π / 2 to 2π. -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0052] Furthermore, for example, if Φ = π / 2 to 3π / 2, the calculation unit 70 calculates P1 = P - tan. -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0053] Furthermore, for example, if the value of Y calculated by Y=(A1+B1)-(A2+B2) is positive, the calculation unit 70 calculates P1=P+tan -1 The value of P1 is calculated using (Δr × sinΦ / r).

[0054] Furthermore, for example, if the value of Y calculated by Y=(A1+B1)-(A2+B2) is negative, the calculation unit 70 calculates P1=P-tan -1The value of P1 is calculated using (Δr × sinΦ / r).

[0055] Details of the calculation method used by the calculation unit 70 will be described later.

[0056] The output unit 60 outputs a signal indicating the value of P1 calculated by the calculation unit 70.

[0057] The functional configuration of encoder 10 has been explained above.

[0058] Figure 6 is a schematic diagram showing a state in which the axis B of the annular region 26 is eccentric with respect to the rotation axis A. Figure 7 is a schematic diagram showing an example of the change in the position of the light (see H in Figure 7) irradiated onto the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 as the rotating plate 20 rotates, in a state in which the axis B of the annular region 26 is eccentric with respect to the rotation axis A. Figure 8 is a graph showing an example of the signal output by the output unit 60 as the rotating plate 20 rotates, in a state in which the axis B of the annular region 26 is eccentric with respect to the rotation axis A. The signal output by the output unit 60 will be explained with reference to Figures 6 to 8.

[0059] As shown in Figure 6, when the axis B of the annular region 26 is eccentric with respect to the rotation axis A, the position of the light irradiated onto the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 via the annular region 26 changes as the rotating plate 20 rotates.

[0060] For example, when the rotating plate 20 is located at the position indicated by T1 in Figure 7, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on one side in the Y-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 7).

[0061] Furthermore, for example, when the rotating plate 20 is located at the position indicated by T2 in Figure 7, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on one side in the X-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 7).

[0062] Furthermore, for example, when the rotating plate 20 is located at the position indicated by T3 in Figure 7, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on the other side in the Y-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 7).

[0063] Furthermore, for example, when the rotating plate 20 is located at the position indicated by T4 in Figure 7, the position of the light when the axis B of the annular region 26 is eccentric with respect to the rotation axis A is located on the other side in the X-axis direction compared to the position of the light when the axis B of the annular region 26 is not eccentric with respect to the rotation axis A (see the dashed line in Figure 7).

[0064] As shown in Figure 8, when the axis B of the annular region 26 is eccentric with respect to the rotation axis A, the output unit 60 outputs a signal indicating the displacement in the X-axis direction and a signal indicating the displacement in the Y-axis direction when the rotating plate 20 rotates. This indicates that the axis B of the annular region 26 is eccentric with respect to the rotation axis A. In the following explanation, the signal indicating the displacement in the X-axis direction may be referred to as the first signal, and the signal indicating the displacement in the Y-axis direction may be referred to as the second signal.

[0065] The signals output by the output unit 60 have been described above.

[0066] Figure 9 is a flowchart showing an example of the calculation method of the calculation unit 70 of the encoder 10 in Figure 1. Referring to Figure 9, an example of the calculation method of the calculation unit 70 will be explained.

[0067] As shown in Figure 9, first, the calculation unit 70 matches the amplitude of the first signal with the amplitude of the second signal (step S1). As described above, the first signal is a signal indicating the shift in the X-axis direction, and the second signal is a signal indicating the shift in the Y-axis direction.

[0068] The calculation unit 70 matches the amplitude of the first signal with the amplitude of the second signal and determines the eccentric phase of axis B with respect to the rotation axis A and the amount of eccentricity of axis B with respect to the rotation axis A (step S2). For example, the eccentric phase of axis B with respect to the rotation axis A is calculated using the X value indicated by the first signal and the Y value indicated by the second signal. Alternatively, for example, the amount of eccentricity of axis B with respect to the rotation axis A is calculated from the amplitude of the first signal. Alternatively, for example, the amount of eccentricity of axis B with respect to the rotation axis A is calculated from a pre-prepared table or function. The amplitude for calculating the amount of eccentricity may be determined sequentially from the square root of the sum of the squares of the first and second signals whose amplitudes have been matched. Specifically, for example, if the amplitude for calculating the amount of eccentricity is G, G may be calculated in real time using the following formula.

[0069]

number

[0070] The calculation unit 70 determines the eccentric phase and eccentricity amount, and then calculates the angle (step S3). For example, when the true detection address is P1, P1 = P ± tan -1 The true detection address is calculated using (Δr × sinΦ / r). Here, as described above, P is the rotation angle of the rotating plate 20 detected based on the light emitted from the emission unit 40 and received by the light receiving unit 50 via one or more patterns, r is the radius of the annular region 26, Δr is the eccentricity of the axis B of the annular region 26 with respect to the rotation axis A, and Φ is the eccentric phase of the axis B of the annular region 26 with respect to the rotation axis A.

[0071] The above describes an example of the calculation method of the calculation unit 70.

[0072] Figure 10 is a flowchart illustrating another example of the calculation method of the calculation unit 70 of the encoder 10 in Figure 1. Referring to Figure 10, another example of the calculation method of the calculation unit 70 will be explained. Note that the following explanation will mainly focus on the differences from the example calculation method shown in Figure 9.

[0073] As shown in Figure 10, first, the calculation unit 70 acquires the amplitude of the second signal (step S11). For example, the calculation unit 70 acquires the amplitude of the second signal from one rotation prior. For example, the calculation unit 70 acquires the amplitude of the second signal from one rotation in test mode or from one rotation during continuous rotation. Specifically, for example, the calculation unit 70 acquires the amplitude of the second signal from data of any 360 degrees. Alternatively, for example, the calculation unit 70 acquires the amplitude of the second signal by clipping the peak value from data of any 180 degrees.

[0074] When the calculation unit 70 acquires the amplitude of the second signal, it determines the eccentric phase of axis B with respect to the rotation axis A and the amount of eccentricity of axis B with respect to the rotation axis A (step S2). For example, the calculation unit 70 estimates the waveform of the second signal from the acquired amplitude of the second signal and determines the eccentric phase of axis B with respect to the rotation axis A from the Y value indicated by the second signal output from the output unit 60 and the trend of increase or decrease in the signal level of the second signal.

[0075] Thus, the calculation unit 70 may calculate the eccentric phase of the axis B with respect to the rotation axis A without using the first signal.

[0076] The above describes another example of the calculation method of the calculation unit 70.

[0077] As described above, the encoder 10 can detect the eccentricity of the rotating plate 20 with respect to the object to be detected 1 with greater accuracy. Furthermore, since the encoder 10 can provide the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 on a single substrate 30, a smaller and less expensive encoder 10 can be provided.

[0078] The encoder 10 according to the first embodiment has been described above.

[0079] The encoder 10 according to the first embodiment includes an emission unit 40 that emits light, a rotating plate 20 which is provided so as to surround the rotation axis A of the rotating plate 20 and has an annular region 26 that reflects the light emitted from the emission unit 40, and a light receiving unit 50 that receives the light emitted from the emission unit 40 and that has passed through the annular region 26. The light receiving unit 50 has a first set having a first light receiving region 55 and a second light receiving region 56 arranged in a first direction E that intersects the rotation direction C of the rotating plate 20, and a second set having a third light receiving region 57 and a fourth light receiving region 58 arranged in a second direction F that intersects the rotation direction C, and provided alongside the first set in the rotation direction C.

[0080] According to this, the device has a first set having a first light-receiving region 55 and a second light-receiving region 56 aligned in a first direction E that intersects the rotation direction C of the rotating plate 20, and a second set having a third light-receiving region 57 and a fourth light-receiving region 58 aligned in a second direction F that intersects the rotation direction C, and provided alongside the first set in the rotation direction C. As a result, as the rotating plate 20 rotates, the position of the light received by the first light-receiving region 55, the second light-receiving region 56, the third light-receiving region 57, and the fourth light-receiving region 58 changes, allowing for accurate detection of the eccentricity of the rotating plate 20 with respect to the object to be detected 1.

[0081] Furthermore, the encoder 10 according to the first embodiment further includes an output unit 60 that outputs a signal indicating the following X value and Y value, when the signal value corresponding to the light received by the first light receiving area 55 is A1, the signal value corresponding to the light received by the second light receiving area 56 is A2, the signal value corresponding to the light received by the third light receiving area 57 is B1, and the signal value corresponding to the light received by the fourth light receiving area 58 is B2.

[0082] X = (A1 + B2) - (B1 + A2) Y=(A1+B1)-(A2+B2)

[0083] According to this, since a signal corresponding to the position of the rotating plate 20 can be output, the eccentricity of the rotating plate 20 with respect to the detection target 1 can be detected with higher accuracy.

[0084] Also, in the encoder 10 according to the first embodiment, the output unit 60 outputs a signal indicating the following value of Q.

[0085] Q = A1 + B1 + A2 + B2

[0086] According to this, since a signal corresponding to the position of the rotating plate 20 can be output, the eccentricity of the rotating plate 20 with respect to the detection target 1 can be detected with higher accuracy.

[0087] Also, in the encoder 10 according to the first embodiment, the output unit 60 outputs a signal indicating the following value of X1 and a signal indicating the following value of Y1.

[0088] X1 = X / Q Y1 = Y / Q

[0089] According to this, since a signal corresponding to the position of the rotating plate 20 can be output, the eccentricity of the rotating plate 20 with respect to the detection target 1 can be detected with higher accuracy.

[0090] Also, in the encoder 10 according to the first embodiment, the rotating plate 20 has one or more patterns for detecting the rotation angle of the rotating plate 20, the light receiving unit 50 has one or more light receiving regions for receiving the light emitted from the light emitting unit 40 and passing through the one or more patterns, and the rotation angle of the rotating plate 20 detected based on the light received by the one or more light receiving regions after being emitted from the light emitting unit 40 and passing through the one or more patterns is P, the eccentricity amount of the axis B of the annular region 26 with respect to the rotation axis A is Δr, the eccentricity phase of the axis B with respect to the rotation axis A is Φ, and the radius of the annular region 26 is r, the encoder 10 further includes a calculation unit 70 that calculates the following value of P1, P1 = P + tan -1 (Δr × sin Φ / r) Or, P1 = P - tan -1 (Δr × sin Φ / r) The output unit 60 outputs a signal indicating the value of P1 calculated by the calculation unit 70.

[0091] According to this, even if the rotating plate 20 is eccentric with respect to the object to be detected 1, the correct position of the object to be detected 1 can be detected.

[0092] Furthermore, in the encoder 10 according to the first embodiment, the first set and the second set are provided with the ejection section 40 in the rotation direction C.

[0093] According to this, the decrease in the amount of light received by the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 can be suppressed, so the eccentricity of the rotating plate 20 with respect to the detection target 1 can be detected with even greater accuracy.

[0094] Furthermore, in the encoder 10 according to the first embodiment, the first direction E and the second direction F are directions parallel to a straight line G perpendicular to the rotation axis A, and the first set and the second set are arranged symmetrically with respect to the straight line G as the axis of symmetry.

[0095] Since the amount of light received by the first light-receiving area 55, the second light-receiving area 56, the third light-receiving area 57, and the fourth light-receiving area 58 is reduced and variations in light intensity are suppressed, the eccentricity of the rotating plate 20 relative to the detection target 1 can be detected with even greater accuracy.

[0096] Furthermore, in the encoder 10 according to the first embodiment, the dimension L from the end of the first light-receiving region 55 opposite to the second light-receiving region 56 in the first direction E is greater than the dimension W2 in the first direction of the light emitted from the emission unit 40 and irradiated onto the first light-receiving region 55 and the second light-receiving region 56 via the annular region 26, and the dimension from the end of the third light-receiving region 57 opposite to the fourth light-receiving region 58 in the second direction F is greater than the dimension in the second direction F of the light emitted from the emission unit 40 and irradiated onto the third light-receiving region 57 and the fourth light-receiving region 58 via the annular region 26.

[0097] According to this, when the rotating plate 20 is eccentric with respect to the detection target 1, the position of the light received by the first light-receiving area 55 and the second light-receiving area 56, and the position of the light received by the third light-receiving area 57 and the fourth light-receiving area 58 can be appropriately changed as the rotating plate 20 rotates, so that the eccentricity of the rotating plate 20 with respect to the detection target 1 can be detected with even greater accuracy.

[0098] Furthermore, in the encoder 10 according to the first embodiment, the emission unit 40 has a point light source, and the dimension between the annular region 26 in the axial direction to which the rotation axis A extends and the emission unit 40 is h1, the dimension between the annular region 26 in the axial direction to which the rotation axis A extends and the first light receiving region 55 and the second light receiving region 56 is h2, the dimension from the end of the first light receiving region 55 opposite to the second light receiving region 56 in the first direction E is L, the dimension of the annular region 26 in the first direction E is W1, and the dimension in the first direction E of the light emitted from the point light source and irradiated onto the first light receiving region 55 and the second light receiving region 56 via the annular region 26 is W2, then W2 = ( (h1+ h2 ) The conditions are that ( / h1) × W1 and W2 / L < 1.

[0099] According to this, when the rotating plate 20 is eccentric with respect to the detection target 1, the position of the light received by the first light-receiving area 55 and the second light-receiving area 56 can be appropriately changed as the rotating plate 20 rotates, so that the eccentricity of the rotating plate 20 with respect to the detection target 1 can be detected with even greater accuracy.

[0100] (Second Embodiment) Figure 11 is a schematic diagram of the rotating plate 20a of the encoder according to the second embodiment, viewed from the axial direction. Figure 12 is a schematic diagram of the light-emitting section 40a and light-receiving section 50a of the encoder in Figure 11, viewed from the axial direction. The configuration of the encoder according to the second embodiment will be described with reference to Figures 11 and 12. In the following, the differences from the encoder 10 according to the first embodiment will be mainly described.

[0101] Note that in Figure 11, only half of the rotating plate 20a is shown to avoid making the drawing too complex.

[0102] As shown in Figure 11, the encoder according to the second embodiment is equipped with a rotating plate 20a that is different from the rotating plate 20. Also, as shown in Figure 12, the encoder according to the second embodiment is equipped with an output unit 40a that is different from the output unit 40 and a light receiving unit 50a that is different from the light receiving unit 50. The encoder according to the second embodiment differs from the encoder 10 in these respects.

[0103] As shown in Figure 11, the rotating plate 20a has a main body 21, an absolute pattern 22a, an incremental pattern 24a, and an annular region 26a.

[0104] The annular region 26a is an annular region provided so as to surround the axis of rotation A and reflects the light emitted from the emission section 40a. The annular region 26a reflects the light emitted from the emission section 40a toward the light receiving section 50a. The annular region 26a is provided on the main surface of the main body 21 on the side of the emission section 40a. The direction in which the axis B of the annular region 26a extends coincides with the axial direction. For example, the annular region 26a is composed of continuously arranged annular reflective sections that reflect the light emitted from the emission section 40a toward the light receiving section 50a.

[0105] As shown in Figure 12, the emission unit 40a emits light. Specifically, the emission unit 40a emits light toward the rotating plate 20a. More specifically, the emission unit 40a emits light toward the absolute pattern 22a, the incremental pattern 24a, and the annular region 26a. The emission unit 40a is provided on the main surface of the substrate 30 on the rotating plate 20a side.

[0106] The light-receiving unit 50a receives light emitted from the emission unit 40a and passing through the annular region 26a. The light-receiving unit 50a has a first absolute light-receiving region 51a, a second absolute light-receiving region 52a, a first incremental light-receiving region 53a, a second incremental light-receiving region 54a, a first set, and a second set.

[0107] The first absolute light-receiving region 51a and the second absolute light-receiving region 52a each receive light emitted from the emission section 40a and that has passed through the absolute pattern 22a. The first absolute light-receiving region 51a and the second absolute light-receiving region 52a are arranged offset from each other in the rotational direction C.

[0108] The first incremental light-receiving area 53a and the second incremental light-receiving area 54a each receive light emitted from the emission section 40a and that has passed through the incremental pattern 24a. The first incremental light-receiving area 53a and the second incremental light-receiving area 54a are arranged offset from each other in the rotational direction C.

[0109] The first set has a first light-receiving region 55a and a second light-receiving region 56a aligned in a first direction E that intersects with the rotation direction C of the rotating plate 20a. The second set has a third light-receiving region 57a ​​and a fourth light-receiving region 58a aligned in a second direction F that intersects with the rotation direction C, and is provided alongside the first set in the rotation direction C.

[0110] The end of the first light-receiving region 55a on the side of the second light-receiving region 56a, the end of the second light-receiving region 56a on the side of the first light-receiving region 55a, the end of the third light-receiving region 57a ​​on the side of the fourth light-receiving region 58a, and the end of the fourth light-receiving region 58a on the side of the third light-receiving region 57a ​​are all straight lines along the tangential direction of the rotation direction C.

[0111] Furthermore, the end of the first light-receiving region 55a opposite to the second light-receiving region 56a, the end of the second light-receiving region 56a opposite to the first light-receiving region 55a, the end of the third light-receiving region 57a ​​opposite to the fourth light-receiving region 58a, and the end of the fourth light-receiving region 58a opposite to the third light-receiving region 57a ​​are all straight lines along the tangential direction of the rotation direction C.

[0112] The encoder according to the second embodiment has been described above.

[0113] In the encoder according to the second embodiment, the end of the first light-receiving area 55a on the side of the second light-receiving area 56a, the end of the second light-receiving area 56a on the side of the first light-receiving area 55a, the end of the third light-receiving area 57a on the side of the fourth light-receiving area 58a, and the end of the fourth light-receiving area 58a on the side of the third light-receiving area 57a are all straight lines along the tangential direction of the rotation direction C.

[0114] According to this, the decrease in the amount of light received by the first light-receiving area 55a, the second light-receiving area 56a, the third light-receiving area 57a, and the fourth light-receiving area 58a can be suppressed, so the eccentricity of the rotating plate 20a with respect to the detection target 1 can be detected with even greater accuracy.

[0115] (Third embodiment) Figure 13 is a schematic diagram of the rotating plate 20b of the encoder according to the third embodiment, viewed from the axial direction. Figure 14 is a schematic diagram of the light output section 40b and light receiving section 50b of the encoder in Figure 13, viewed from the axial direction. The configuration of the encoder according to the third embodiment will be described with reference to Figures 13 and 14. In the following, the differences from the encoder 10 according to the first embodiment will be mainly described.

[0116] Note that in Figure 13, only half of the rotating plate 20b is shown to avoid making the drawing too complex.

[0117] As shown in Figure 13, the encoder according to the third embodiment includes a rotating plate 20b that is different from the rotating plate 20. Also, as shown in Figure 14, the encoder according to the third embodiment includes an output unit 40b that is different from the output unit 40 and a light receiving unit 50b that is different from the light receiving unit 50. The encoder according to the third embodiment differs from the encoder 10 in these respects.

[0118] As shown in Figure 13, the rotating plate 20b has a main body 21, an absolute pattern 22b, an incremental pattern 24b, and an annular region 26b.

[0119] The annular region 26b is an annular region provided so as to surround the axis of rotation A and reflects the light emitted from the emission section 40b. The annular region 26b reflects the light emitted from the emission section 40b toward the light receiving section 50b. The annular region 26b is provided on the main surface of the main body 21 on the emission section 40b side. The direction in which the axis B of the annular region 26b extends coincides with the axial direction. For example, the annular region 26b is composed of continuously arranged annular reflective sections that reflect the light emitted from the emission section 40b toward the light receiving section 50b.

[0120] The annular region 26b is positioned inward of the absolute pattern 22b and the incremental pattern 24b in the radial direction centered on the axis B. In other words, of the absolute pattern 22b, the incremental pattern 24b, and the annular region 26b, the annular region 26b is positioned furthest inward in that radial direction.

[0121] As shown in Figure 14, the emission unit 40b emits light. Specifically, the emission unit 40b emits light toward the rotating plate 20b. More specifically, the emission unit 40b emits light toward the absolute pattern 22b, the incremental pattern 24b, and the annular region 26b. The emission unit 40b is provided on the main surface of the substrate 30 on the rotating plate 20b side.

[0122] The light-receiving unit 50b receives light emitted from the emission unit 40b and passing through the annular region 26b. The light-receiving unit 50b has a first absolute light-receiving region 51b, a second absolute light-receiving region 52b, a first incremental light-receiving region 53b, a second incremental light-receiving region 54b, a first set, and a second set.

[0123] The first absolute light-receiving region 51b and the second absolute light-receiving region 52b each receive light emitted from the emission section 40b and that has passed through the absolute pattern 22b.

[0124] The first incremental light-receiving area 53b and the second incremental light-receiving area 54b each receive light emitted from the emission section 40b and that has passed through the incremental pattern 24b.

[0125] The first set has a first light-receiving region 55b and a second light-receiving region 56b aligned in a first direction E that intersects with the rotation direction C of the rotating plate 20b. The second set has a third light-receiving region 57b and a fourth light-receiving region 58b aligned in a second direction F that intersects with the rotation direction C, and is provided alongside the first set in the rotation direction C.

[0126] Each of the first and second sets is positioned inward from the emission section 40b in the radial direction centered on the rotation axis A. In other words, in the radial direction centered on the rotation axis A, each of the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b is positioned inward from the emission section 40b.

[0127] The end of the first light-receiving region 55b on the side of the second light-receiving region 56b, the end of the second light-receiving region 56b on the side of the first light-receiving region 55b, the end of the third light-receiving region 57b on the side of the fourth light-receiving region 58b, and the end of the fourth light-receiving region 58b on the side of the third light-receiving region 57b are all curved in the direction of rotation C.

[0128] Furthermore, the end of the first light-receiving region 55b opposite to the second light-receiving region 56b, the end of the second light-receiving region 56b opposite to the first light-receiving region 55b, the end of the third light-receiving region 57b opposite to the fourth light-receiving region 58b, and the end of the fourth light-receiving region 58b opposite to the third light-receiving region 57b are all curved along the rotational direction C.

[0129] Each of the first light-receiving region 55b, the second light-receiving region 56b, the third light-receiving region 57b, and the fourth light-receiving region 58b is arc-shaped along the rotation direction C.

[0130] The first direction E is the direction that coincides with the radial direction centered on the axis of rotation A, and the second direction F is the direction that coincides with the radial direction centered on the axis of rotation A and intersects with the first direction E.

[0131] The first light-receiving region 55b and the third light-receiving region 57b are adjacent in the rotation direction C, and the second light-receiving region 56b and the fourth light-receiving region 58b are adjacent in the rotation direction C.

[0132] The encoder according to the third embodiment has been described above.

[0133] In the encoder according to the third embodiment, the first set and the second set are each arranged inward from the ejection section 40b in the radial direction with respect to the rotation axis A.

[0134] According to this, the light received by the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b can be more easily curved, so the eccentricity of the rotating plate 20b with respect to the detection target 1 can be detected with even greater accuracy.

[0135] Furthermore, in the encoder according to the third embodiment, the end of the first light-receiving area 55b on the second light-receiving area 56b side, the end of the second light-receiving area 56b on the first light-receiving area 55b side, the end of the third light-receiving area 57b on the fourth light-receiving area 58b side, and the end of the fourth light-receiving area 58b on the third light-receiving area 57b side are all curved in line with the rotation direction C.

[0136] According to this, the decrease in the amount of light received by the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b can be suppressed, so the eccentricity of the rotating plate 20b relative to the detection target 1 can be detected with even greater accuracy.

[0137] Furthermore, in the encoder according to the third embodiment, the first direction E is a direction that coincides with the radial direction centered on the rotation axis A, and the second direction F is a direction that coincides with the radial direction centered on the rotation axis A and intersects with the first direction E.

[0138] Since the decrease in the amount of light received by the first light-receiving area 55b, the second light-receiving area 56b, the third light-receiving area 57b, and the fourth light-receiving area 58b can be further suppressed, the eccentricity of the rotating plate 20b relative to the detection target 1 can be detected with even greater accuracy.

[0139] (Fourth embodiment) Figure 15 is a schematic diagram of the output section 40c and the receiving section 50c of the encoder according to the fourth embodiment, viewed from the axial direction. The configuration of the encoder according to the fourth embodiment will be described with reference to Figure 15. In the following, the differences from the encoder 10 according to the first embodiment will be mainly described.

[0140] As shown in Figure 15, the encoder according to the fourth embodiment differs from the encoder 10 in that it includes a rotating plate (not shown) different from the rotating plate 20, an emission unit 40c different from the emission unit 40, and a light receiving unit 50c different from the light receiving unit 50.

[0141] The emission unit 40c emits light. Specifically, the emission unit 40c emits light toward the rotating plate. More specifically, the emission unit 40c emits light toward an annular region (not shown) of the rotating plate. The emission unit 40c is provided on the main surface of the substrate 30 on the rotating plate side.

[0142] The light-receiving unit 50c receives light emitted from the emission unit 40c and passing through the annular region of the rotating plate of the encoder according to the fourth embodiment. The light-receiving unit 50c has a first absolute light-receiving region 51c, a second absolute light-receiving region 52c, a first incremental light-receiving region 53c, a second incremental light-receiving region 54c, a first set, and a second set.

[0143] The first absolute light-receiving region 51c and the second absolute light-receiving region 52c each receive light emitted from the emission section 40c that has passed through the absolute pattern of the rotating plate.

[0144] The first incremental light-receiving area 53c and the second incremental light-receiving area 54c each receive light emitted from the emission section 40c that has passed through the incremental pattern of the rotating plate.

[0145] The first set has a first light-receiving region 55c and a second light-receiving region 56c aligned in a first direction E that intersects the rotation direction C of the rotating plate. The second set has a third light-receiving region 57c and a fourth light-receiving region 58c aligned in a second direction F that intersects the rotation direction C, and is provided alongside the first set in the rotation direction C.

[0146] The first and second sets are positioned with a 90-degree phase difference in the rotational direction C. In other words, the second set is positioned 90 degrees away from the first set in the rotational direction C.

[0147] The encoder according to the fourth embodiment has been described above.

[0148] (Fifth embodiment) Figure 16 is an explanatory diagram illustrating the relationship between the dimensions of the first light-receiving area 55d and the second light-receiving area 56d and the dimensions of the light irradiated onto the first light-receiving area 55d and the second light-receiving area 56d in the encoder according to the fifth embodiment. The configuration of the encoder according to the fifth embodiment will be described with reference to Figure 16.

[0149] As shown in Figure 16, in this embodiment, the emission unit 40d has a surface light source, and the dimension between the annular region 26d and the emission unit 40d in the axial direction to which the rotation axis A extends is h1, the dimension between the annular region 26d and the first light-receiving region 55d and the second light-receiving region 56d in the axial direction to which the rotation axis A extends is h2, the dimension from the end of the first light-receiving region 55d opposite to the second light-receiving region 56d in the first direction E is L, the dimension of the annular region 26d in the first direction E is W1, the dimension of the light emitted from the surface light source and irradiated onto the first light-receiving region 55d and the second light-receiving region 56d via the annular region 26d in the first direction E is W2, and the dimension of the light emission opening of the surface light source in the first direction E is D, then W2 = ((h2 / h1) + 1) × W1 + (h2 / h1) × It is desirable to design the sensor such that D satisfies W2 / L < 1, and even if the reflected light on the light-receiving surface moves due to the maximum correctable eccentricity, the reflected light does not extend beyond the light-receiving region (first light-receiving region 55d and second light-receiving region 56d). The same relationship is also satisfied for the third and fourth light-receiving regions.

[0150] The encoder according to the fifth embodiment has been described above.

[0151] In the encoder according to the fifth embodiment, the emission unit 40d has a surface light source, and the dimension between the annular region 26d in the axial direction to which the rotation axis A extends and the emission unit 40d is h1, the dimension between the annular region 26d in the axial direction to which the rotation axis A extends and the first light receiving region 55d and the second light receiving region 56d is h2, the dimension from the end of the first light receiving region 55d opposite to the second light receiving region 56d in the first direction E is L, the dimension of the annular region 26d in the first direction E is W1, the dimension of the light emitted from the surface light source and irradiated onto the first light receiving region 55d and the second light receiving region 56d via the annular region 26d in the first direction E is W2, and the dimension of the light emission opening of the surface light source in the first direction E is D, then W2 = ((h2 / h1) + 1) × W1 + (h2 / h1) × D and W2 / L < 1.

[0152] According to this, when the rotating plate is eccentric with respect to the detection target 1, the position of the light received by the first light-receiving area 55d and the second light-receiving area 56d can be appropriately changed as the rotating plate rotates, thereby enabling more accurate detection of the eccentricity of the rotating plate with respect to the detection target 1.

[0153] (Sixth Embodiment) Figure 17 is an explanatory diagram illustrating the relationship between the dimensions of the first light-receiving area 55e and the second light-receiving area 56e and the dimensions of the light irradiated onto the first light-receiving area 55e and the second light-receiving area 56e in the encoder according to the sixth embodiment. The configuration of the encoder according to the sixth embodiment will be described with reference to Figure 17. In the following, the differences from the encoder 10 according to the first embodiment will be mainly described.

[0154] As shown in Figure 17, the encoder according to the sixth embodiment includes an emission section 40e, an annular region 26e, a first light-receiving region 55e, and a second light-receiving region 56e.

[0155] The annular region 26e is concave in the direction of the axis along which the rotation axis A extends. Light emitted from the emission section 40e and reflected by the annular region 26e converges and illuminates the first light-receiving region 55e and the second light-receiving region 56e. Similarly, light emitted from the emission section 40e and reflected by the annular region 26e converges and illuminates the third light-receiving region and the fourth light-receiving region.

[0156] The encoder according to the sixth embodiment has been described above.

[0157] In the encoder according to the sixth embodiment, the annular region 26e is recessed in the axial direction to which the rotation axis A extends.

[0158] According to this, the decrease in the intensity of light received by the first light-receiving area 55e, the second light-receiving area 56e, the third light-receiving area, and the fourth light-receiving area can be suppressed, so that the eccentricity of the rotating plate with respect to the detection target 1 can be detected with even greater accuracy.

[0159] (Seventh Embodiment) Figure 18 is a flowchart showing an example of a mounting method according to the seventh embodiment. Referring to Figure 18, an example of a mounting method according to the seventh embodiment will be described. Here, a mounting method for attaching the encoder 10 to the detection target 1 will be described.

[0160] As shown in Figure 18, first, the rotating plate 20 is attached to the detection target 1 (step S21). For example, the rotating plate 20 is attached to the detection target 1 using screws or the like.

[0161] When the rotating plate 20 is attached to the object to be detected 1, the rotating plate 20 is rotated around the rotation axis A (step S22). However, it is not always necessary to rotate the rotating plate 20.

[0162] After rotating the rotating plate 20 around the rotation axis A, the signal output by the output unit 60 is acquired (step S23). The X and Y values ​​are obtained from the signal output by the output unit 60.

[0163] When the signal output by the output unit 60 is acquired, it is determined whether the value of X and the value of Y are both 0 (step S24).

[0164] If neither the X value nor the Y value is 0 (No in step S24), the mounting position of the rotating plate 20 relative to the detection target 1 is adjusted (step S25).

[0165] In this manner, if neither the X value nor the Y value is zero, the mounting position of the rotating plate 20 relative to the detection target 1 is adjusted, and it is determined again whether neither the X value nor the Y value is zero. Then, the encoder 10 is mounted to the detection target 1 so that the X value output by the output unit 60 becomes zero and the Y value becomes zero.

[0166] The mounting method according to the seventh embodiment has been described above.

[0167] The mounting method according to the seventh embodiment is a mounting method for mounting the encoder 10 to the detection target 1, wherein the encoder 10 comprises an emission unit 40 that emits light, a rotating plate 20 which is provided so as to surround the rotation axis A of the rotating plate 20 and has an annular region 26 that reflects the light emitted from the emission unit 40, and a light receiving unit 50 that receives the light emitted from the emission unit 40 and that has passed through the annular region 26, the light receiving unit 50 comprises a first set having a first light receiving region 55 and a second light receiving region 56 arranged in a first direction E that intersects the rotation direction C of the rotating plate 20, The system further includes an output unit 60 which has a third light-receiving region 57 and a fourth light-receiving region 58 arranged in a second direction F intersecting the rotation direction C, and a second set provided alongside the first set in the rotation direction C, wherein when the signal value corresponding to the light received by the first light-receiving region 55 is A1, the signal value corresponding to the light received by the second light-receiving region 56 is A2, the signal value corresponding to the light received by the third light-receiving region 57 is B1, and the signal value corresponding to the light received by the fourth light-receiving region 58 is B2, the system further includes an output unit 60 which outputs a signal indicating the following X value and Y value, X = (A1 + B2) - (B1 + A2) Y=(A1+B1)-(A2+B2) The process includes step S21 of attaching the rotating plate 20 to the detection target 1, and step S23 of causing the output unit 60 to output a signal indicating the value of X and a signal indicating the value of Y after the rotating plate 20 has been attached to the detection target 1, wherein the rotating plate 20 is attached to the detection target 1 such that the value of X indicated by the signal output by the output unit 60 is 0 and the value of Y indicated by the signal output by the output unit 60 is 0.

[0168] This prevents the encoder 10 from being mounted in an eccentric position relative to the detection target 1.

[0169] (Other embodiments, etc.) As described above, embodiments have been explained as examples of the technology disclosed in this application. However, the technology disclosed herein is not limited to these embodiments, and can be applied to embodiments or modified versions that are changed, replaced, added, omitted, etc., as appropriate, as long as they do not deviate from the spirit of this disclosure.

[0170] In the embodiments described above, the case in which the annular regions 26 to 26e reflect light was explained, but the invention is not limited to this. For example, the annular regions may transmit light emitted from the emission portion toward the light receiving portion.

[0171] In the above embodiments, each component may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU (Central Processing Unit) or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory. Here, the software that implements the analysis support method, etc., of each of the above embodiments is a computer program that causes a computer to execute each step of the flowchart shown in Figures 9, 10, and 18, respectively.

[0172] The following cases are also included in this disclosure.

[0173] (1) The at least one device described above is specifically a computer system consisting of a microprocessor, ROM, RAM, hard disk unit, display unit, keyboard, mouse, etc. A computer program is stored in the RAM or hard disk unit. The at least one device described above achieves its function by the operation of the microprocessor in accordance with the computer program. Here, the computer program is composed of a combination of multiple instruction codes that indicate instructions to the computer in order to achieve a predetermined function.

[0174] (2) Some or all of the components constituting at least one of the above-described devices may be made up of a single system LSI (Large Scale Integration). The system LSI is a multi-functional LSI manufactured by integrating multiple components onto a single chip, and specifically, it is a computer system comprising a microprocessor, ROM, RAM, etc. The RAM stores a computer program. The system LSI achieves its function by operating the microprocessor in accordance with the computer program.

[0175] (3) Some or all of the components constituting at least one of the above-described devices may consist of an IC card or a standalone module that is detachable from the device. The IC card or module is a computer system consisting of a microprocessor, ROM, RAM, etc. The IC card or module may include the above-described multi-function LSI. The IC card or module achieves its function by the operation of the microprocessor in accordance with a computer program. The IC card or module may be tamper-resistant.

[0176] (4) The disclosure may also be the methods described above. Alternatively, it may be a computer program that implements these methods using a computer, or a digital signal consisting of a computer program.

[0177] Furthermore, this disclosure may also refer to a computer program or digital signal recorded on a computer-readable recording medium, such as a flexible disk, hard disk, CD (Compact Disc)-ROM, DVD, DVD-ROM, DVD-RAM, BD (Blu-ray® Disc), semiconductor memory, etc. Alternatively, it may refer to a digital signal recorded on such a recording medium.

[0178] Furthermore, this disclosure may also include the transmission of computer programs or digital signals via telecommunications lines, wireless or wired communication lines, networks such as the Internet, data broadcasting, etc.

[0179] Alternatively, the program or digital signal may be carried out by another independent computer system by recording and transferring it on a recording medium, or by transferring the program or digital signal via a network or the like. [Industrial applicability]

[0180] The encoder described herein can be used to detect the rotation of a motor's rotating shaft or the like, which drives a load. [Explanation of symbols]

[0181] 10 encoders 20, 20a, 20b Rotating plate 21 Main unit 22. First Absolute Pattern 22a, 22b Absolute Pattern 23. Second Absolute Pattern 24. First Incremental Pattern 24a, 24b Incremental pattern 25. Second Incremental Pattern 26,26a,26b,26d,26e Circular region 30 circuit boards 40,40a,40b,40c,40d,40e Output part 50,50a,50b,50c Light receiving section 51, 51a, 51b, 51c First absolute photoreceiving region 52, 52a, 52b, 52c Second absolute photoreceiving region 53, 53a, 53b, 53c First incremental light-receiving region 54, 54a, 54b, 54c Second incremental light-receiving region 55,55a,55b,55c,55d,55e 1st light receiving area 56,56a,56b,56c,56d,56e 2nd light receiving area 57,57a,57b,57c 3rd light receiving area 58,58a,58b,58c 4th light receiving area 60 Output section 70 Calculation Unit

Claims

1. A light-emitting section and A rotating plate having an annular region that surrounds the axis of rotation of the rotating plate and reflects or transmits light emitted from the emission portion, The system includes a light receiving unit that receives light emitted from the emission unit and that has passed through one of the annular regions, The light-receiving unit comprises a first set having a first light-receiving region and a second light-receiving region aligned in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light-receiving region and a fourth light-receiving region aligned in a second direction intersecting the rotation direction, and provided alongside the first set in the rotation direction. Encoder.

2. The device further includes an output unit that outputs a signal indicating the following X value and Y value, where A1 is the signal value corresponding to the light received by the first light-receiving region, A2 is the signal value corresponding to the light received by the second light-receiving region, B1 is the signal value corresponding to the light received by the third light-receiving region, and B2 is the signal value corresponding to the light received by the fourth light-receiving region. X=(A1+B2)-(B1+A2) Y=(A1+B1)-(A2+B2) The encoder according to claim 1.

3. The output unit outputs a signal showing the following Q values: Q=A1+B1+A2+B2 The encoder according to claim 2.

4. The output unit outputs a signal indicating the value of X1 and a signal indicating the value of Y1, X1 = X / Q Y1 = Y / Q The encoder according to claim 3.

5. The rotating plate has one or more patterns for detecting the rotation angle of the rotating plate. The light-receiving unit has one or more light-receiving regions that receive light emitted from the emission unit and that has passed through one or more patterns. The calculation unit further comprises a calculation unit that calculates the following value of P1, where P is the rotation angle of the rotating plate detected based on the light emitted from the emission unit and received by the one or more light receiving regions after passing through the one or more patterns, Δr is the eccentricity of the axis of the annular region with respect to the rotation axis, Φ is the eccentric phase of the axis with respect to the rotation axis, and r is the radius of the annular region. P1=P+tan －１ (Δr×sinΦ / r) Alternatively, P1 = P - tan －１ (Δr×sinΦ / r) The output unit outputs a signal indicating the value of P1 calculated by the calculation unit. The encoder according to any one of claims 2 to 4.

6. The first set and the second set are provided with the ejection part in the direction of rotation, The encoder according to any one of claims 1 to 4.

7. Each of the first set and the second set is provided inward from the ejection portion in the radial direction with respect to the rotation axis, The encoder according to any one of claims 1 to 4.

8. Each of the ends of the first light-receiving region on the second light-receiving region side, the end of the second light-receiving region on the first light-receiving region side, the end of the third light-receiving region on the fourth light-receiving region side, and the end of the fourth light-receiving region on the third light-receiving region side are curved along the direction of rotation. The encoder according to any one of claims 1 to 4.

9. Each of the ends of the first light-receiving region on the second light-receiving region side, the end of the second light-receiving region on the first light-receiving region side, the end of the third light-receiving region on the fourth light-receiving region side, and the end of the fourth light-receiving region on the third light-receiving region side are in a straight line along the tangential direction of the rotational direction. The encoder according to any one of claims 1 to 4.

10. Each of the first and second directions is a direction parallel to a straight line perpendicular to the axis of rotation, The first set and the second set are arranged symmetrically with respect to the straight line as the axis of symmetry. The encoder according to any one of claims 1 to 4.

11. The first direction is the direction that coincides with the radial direction centered on the axis of rotation, The second direction is a direction that coincides with the radial direction centered on the axis of rotation and intersects with the first direction. The encoder according to any one of claims 1 to 4.

12. The distance from the end of the first light-receiving region opposite to the second light-receiving region in the first direction to the end of the second light-receiving region opposite to the first light-receiving region is greater than the distance in the first direction of the light emitted from the emission unit and irradiated onto the first light-receiving region and the second light-receiving region via the annular region. The distance in the second direction from the end of the third light-receiving region opposite to the fourth light-receiving region to the end of the fourth light-receiving region opposite to the third light-receiving region is greater than the distance in the second direction of the light emitted from the emission section and irradiated onto the third and fourth light-receiving regions via the annular region. The encoder according to any one of claims 1 to 4.

13. The emission unit has a point light source, Let h1 be the dimension between the annular region and the emission portion in the axial direction in which the rotation axis extends, let h2 be the dimension between the annular region and the first light-receiving region and the second light-receiving region in the axial direction in which the rotation axis extends, let L be the dimension from the end of the first light-receiving region opposite to the second light-receiving region in the first direction, let W1 be the dimension of the annular region in the first direction, and let W2 be the dimension in the first direction of the light emitted from the point light source and irradiated onto the first light-receiving region and the second light-receiving region via the annular region, then W2 = ((h1 + h2) / h1) × W1 and W2 / L < 1. The encoder according to claim 12.

14. The emission unit has a surface light source, Let h1 be the dimension between the annular region and the emission part in the axial direction in which the rotation axis extends, let h2 be the dimension between the annular region and the first light-receiving region and the second light-receiving region in the axial direction in which the rotation axis extends, let L be the dimension from the end of the first light-receiving region opposite to the second light-receiving region in the first direction, let W1 be the dimension of the annular region in the first direction, let W2 be the dimension of the light emitted from the surface light source and irradiated onto the first light-receiving region and the second light-receiving region via the annular region in the first direction, and let D be the dimension of the light emission opening of the surface light source in the first direction, then W2 = ((h2 / h1) + 1) × W1 + (h2 / h1) × D and W2 / L < 1. The encoder according to claim 12.

15. The annular region is recessed in the direction of the axis of rotation from which the axis of rotation extends. The encoder according to any one of claims 1 to 4.

16. A mounting method for attaching an encoder to a detection target, The encoder described above is A light-emitting section and A rotating plate having an annular region that surrounds the axis of rotation of the rotating plate and reflects or transmits light emitted from the emission portion, The system includes a light receiving unit that receives light emitted from the emission unit and that has passed through one of the annular regions, The light-receiving unit comprises a first set having a first light-receiving region and a second light-receiving region aligned in a first direction intersecting the rotation direction of the rotating plate, and a second set having a third light-receiving region and a fourth light-receiving region aligned in a second direction intersecting the rotation direction, and provided alongside the first set in the rotation direction. The system further includes an output unit that outputs a signal indicating the following X value and Y value, when the signal value corresponding to the light received by the first light-receiving region is A1, the signal value corresponding to the light received by the second light-receiving region is A2, the signal value corresponding to the light received by the third light-receiving region is B1, and the signal value corresponding to the light received by the fourth light-receiving region is B2. X=(A1+B2)-(B1+A2) Y=(A1+B1)-(A2+B2) The steps include attaching the rotating plate to the object to be detected, The step of attaching the rotating plate to the object to be detected, and then causing the output unit to output a signal indicating the value of X and a signal indicating the value of Y, The rotating plate is attached to the object to be detected such that the value of X indicated by the signal output by the output unit becomes 0 and the value of Y indicated by the signal output by the output unit becomes 0. Installation method.

Images