JP2015049140A - Scale for encoder, encoder, encoder manufacturing method, drive device and robot device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To downsize an encoder with a scale made smaller, and to detect position information with high accuracy.SOLUTION: In a scale S including an optical pattern 33 detectable by an optical detection part 40, the optical pattern 33 includes: a first pattern 34 that is arrayed in a line in a first direction D1 and has a predetermined length in a second direction D2 crossing the first direction D1; and a second pattern 35 that is different in a length from the first pattern 34 in the second direction D2. One of the first pattern 34 and the second pattern 35 has position information on the optical pattern 33 in the first direction D1.

Description

  The present invention relates to an encoder scale, an encoder, an encoder manufacturing method, a drive device, and a robot apparatus.

  An encoder is used to detect the amount of movement and position information of a moving object such as a mover of a linear motor or a drive shaft of a rotary motor. As an example of the encoder, there is an optical encoder, and a configuration including a scale on which an optical pattern is formed and a light detection unit that detects the optical pattern is known (for example, see Patent Document 1). In an optical encoder scale for detecting an absolute amount, two rows of tracks, an incremental track and an absolute track, are formed as an optical pattern in many cases.

  The scale described above is attached to, for example, a drive shaft of a rotary motor, and rotates integrally with the drive shaft. At that time, the optical pattern is irradiated with light, the reflected light or transmitted light is acquired by the light detection unit, and the rotation amount and rotation position of the shaft part are determined based on the incremental signal and the absolute signal according to the change in the light intensity. Detected.

JP 2009-186229 A

  However, the encoder described above uses a scale having two rows of tracks, an incremental track and an absolute track. Therefore, it is difficult to reduce the space because two rows of tracks are required on the scale. As a result, there is a problem that the encoder cannot be reduced in size. The encoder described above is provided with two tracks, an incremental track and an absolute track, on a code plate such as a scale. In this case, it is necessary to attach the scale to the shaft or the like and place the light detection unit so that the detection signal of the incremental track and the detection signal of the absolute track are within the standard. Is required. Therefore, for example, when there is a deviation in the attachment position of the scale or the light detection unit, the above-described encoder may reduce the detection accuracy of the position information. As described above, the encoder described above has a problem that it is difficult to detect position information with high accuracy.

  In view of the circumstances as described above, the present invention realizes downsizing of an encoder by enabling a small scale and capable of detecting position information with high accuracy, an encoder, an encoder manufacturing method, and a drive An object is to provide an apparatus and a robot apparatus.

  According to the first aspect of the present invention, the encoder scale includes an optical pattern that can be detected by the light detection unit, the optical pattern being arranged in a line in the first direction and intersecting the first direction. A first pattern having a predetermined length in the second direction, and a second pattern having a length different from the first pattern in the second direction, and one of the first pattern and the second pattern is the first pattern An encoder scale having position information of an optical pattern in one direction is provided.

  According to the second aspect of the present invention, the encoder scale includes an optical pattern that can be detected by the light detection unit, and the optical pattern is arranged in a line in the first direction and has a predetermined reflectance or transmission. There is provided an encoder scale including a first pattern having a rate and a second pattern having a reflectance or transmittance different from that of the first pattern.

  According to the third aspect of the present invention, there is provided a method for manufacturing an encoder scale having an optical pattern that can be detected by a light detection unit, the optical pattern being arranged in a line in a first direction, A method of manufacturing a scale for an encoder is provided that includes forming a film portion so that a length of a part of a pattern in a second direction intersecting the first direction is different.

  According to a fourth aspect of the present invention, there is provided a method for manufacturing an encoder scale including an optical pattern that can be detected by a light detection unit, wherein the optical pattern is arranged in a line in the first direction, and the optical scale is formed. There is provided a method for manufacturing a scale for an encoder, including coating a film part for adjusting reflectance or transmittance for a part of a pattern.

  According to a fifth aspect of the present invention, an encoder scale having an optical pattern and a light detection unit that detects light via the optical pattern are provided. The encoder scale includes the first aspect or the second aspect described above. An encoder is provided in which a scale for an encoder according to is used.

  According to the sixth aspect of the present invention, the moving member, the drive unit that moves the moving member, and the encoder that is fixed to the moving member and detects position information of the moving member are provided. A drive device is provided in which an encoder according to is used.

  According to the seventh aspect of the present invention, there is provided a robot apparatus that includes a moving object and a driving device that moves the moving object, and uses the driving device according to the sixth aspect described above as the driving device.

  According to the aspect of the present invention, the scale can be reduced and the encoder can be reduced in size. Further, the position information can be detected with high accuracy by preventing the detection accuracy of the position information from being lowered. Furthermore, it is possible to easily attach the scale and install the light detection unit.

(A) is a perspective view which shows an example of the scale for encoders concerning 1st Embodiment, (b) is the top view which expanded a part, (c) is sectional drawing along the AA of (b). is there. It is a graph which shows an example of a detection signal. (A)-(e) is a perspective view which shows the manufacturing process of a scale. (A) is a perspective view which shows an example of the scale which concerns on a 1st modification, (b) is a perspective view which shows an example of the scale which concerns on a 2nd modification. (A) is a perspective view which shows an example of the scale which concerns on a 3rd modification, (b) is sectional drawing along the BB line of (a). (A) is sectional drawing which shows an example of the encoder which concerns on embodiment, (b) is a top view which shows an example of a photon detection part. It is a block diagram which shows the structure of the control circuit of a photon detection part. It is a perspective view which shows an example of the scale for encoders concerning 2nd Embodiment. (A) is a perspective view which shows an example of the scale which concerns on a 4th modification, (b) is sectional drawing along CC line of (a). (A) is a top view which shows an example of the scale for encoders concerning 3rd Embodiment, (b) is a graph which shows an example of a detection signal. It is a top view which shows an example of the photon detection part which concerns on a 5th modification. It is a perspective view which shows an example of the scale for encoders concerning 4th Embodiment. It is a top view which shows an example of the photon detection part which concerns on a 6th modification. It is a figure which shows an example of the drive device which concerns on embodiment. It is a perspective view which shows an example of the robot apparatus which concerns on embodiment.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention is not limited to this. Further, in the drawings, in order to describe the embodiment, the scale is appropriately changed and expressed, for example, partly enlarged or emphasized. In the following description, “encoder scale” may be abbreviated as “scale” as appropriate.

<First Embodiment>
FIG. 1 is a diagram illustrating an example of an encoder scale S according to the first embodiment. The scale S constitutes a part of an optical rotary encoder, for example, and is used by being attached to a shaft portion of a drive system such as a rotary motor. The scale S is a reflective scale.

  As shown in FIG. 1A, the scale S includes a substrate 10 and a fixing portion 20. The substrate 10 is formed in a circular shape having a predetermined diameter around the rotation axis AX. The substrate 10 is formed using a material having such a rigidity that it is not easily deformed by rotation, impact, vibration, or the like, such as glass, metal, resin, or ceramic. Although the substrate 10 is formed with a uniform thickness, for example, the central portion or the like may be formed thicker than the periphery. The material, thickness, dimensions, and the like of the substrate 10 can be appropriately determined according to the use, for example, the number of rotations of the shaft portion to be attached and the installation environment such as the temperature and humidity to be installed.

  The fixing portion 20 is formed in a cylindrical shape that protrudes from the second surface 10 b of the substrate 10. The fixed portion 20 is fixed to a moving member that is a measurement target, such as a shaft portion of a rotary motor or the like. The fixed part 20 has a mounting hole 20a into which a shaft part such as a rotary motor can be inserted. The fixing portion 20 may be provided with a fixing mechanism (not shown) such as a fixing screw for fixing the shaft portion in a state where the shaft portion is inserted into the mounting hole 20a.

  The first surface 10 a of the substrate 10 has a track region 30. The track region 30 is formed in an annular shape along the first direction D1. The first direction D1 is set to an annular direction centering on the rotation axis AX of the substrate 10. The second direction D2 is set on the first surface 10a of the substrate 10 in the radial direction of the substrate 10 passing through the rotation axis AX. The first direction D1 and the second direction D2 are orthogonal to each other. An optical pattern 33 is formed in the track region 30. The optical pattern 33 is a light reflection pattern.

FIG. 1B shows an enlarged part of the first surface 10 a of the substrate 10, and represents the configuration of the track region 30. FIG.2 (c) has shown the cross section along the AA of (b). As shown in FIGS. 2A and 2B, a light reflection layer 31 and a reflection suppression layer 32 are formed in the track region 30. The light reflecting layer 31 is formed using a metal material having high reflectivity such as aluminum or an inorganic material such as silicon oxide (SiO ₂ ). The light reflecting layer 31 is formed in the track region 30, but may be formed on almost the entire first surface 10 a of the substrate 10 including the track region 30. Further, the surface 31a of the light reflecting layer 31 may be mirror-finished.

  In the light reflection layer 31, the reflectance of the surface 31a is set to about 40% or more, for example. However, in order to ensure a sufficient reflectance on the surface 31a of the light reflecting layer 31, the light reflecting layer 31 can be formed so that the reflectance is, for example, 70% or more. In addition, the reflectance here is the reflectance with respect to the detection light used with an optical encoder, for example.

  The reflection suppression layer 32 is formed by being laminated on the surface 31 a of the light reflection layer 31. The reflection suppression layer 32 is formed using, for example, a metal material having a high light absorption rate such as chromium (Cr) or a material having a high light transmittance such as glass. The surface of the reflection suppressing layer 32 has a lower reflectance than the surface 31 a of the light reflecting layer 31. The reflectance ratio between the light reflection layer 31 and the reflection suppression layer 32 can be arbitrarily set. The reflectance ratio is set to an arbitrary value that allows the light detection unit 40 described later to identify the reflected light from the light reflection layer 31.

  The reflection suppression layer 32 has openings 32a and 32b. The openings 32a and 32b are arranged side by side at a pitch p equal to the first direction D1. The openings 32a and 32b are formed in a rectangular shape so as to be long in the second direction D2. The openings 32a and 32b have the same dimension in the first direction D1, but differ in the dimension (track width) in the second direction D2. A dimension L1 of the opening 32a in the second direction D2 is larger than a dimension L2 of the opening 32b in the second direction D2. The opening 32a and the opening 32b are arranged so that their center positions are aligned in the second direction D2. Therefore, the opening 32a is in a state in which both ends in the second direction D2 protrude from the opening 32b by equal dimensions.

  From the openings 32 a and 32 b, the surface 31 a of the light reflection layer 31 disposed below the reflection suppression layer 32 is exposed. The region of the surface 31 a of the light reflecting layer 31 exposed from the openings 32 a and 32 b becomes the optical pattern 33. The optical pattern 33 has a first pattern 34 and a second pattern 35. The first pattern 34 is a pattern formed by a region exposed from the opening 32 a in the surface 31 a of the light reflecting layer 31. The second pattern 35 is a pattern formed by a region exposed from the opening 32 b in the surface 31 a of the light reflecting layer 31. Accordingly, the first pattern 34 and the second pattern 35 have the same dimension in the first direction D1.

  Further, the dimension of the first pattern 34 in the second direction D2 is a dimension L1 that is equal to the dimension of the opening 32a. The dimension of the second direction D2 of the second pattern 35 is a dimension L2 that is equal to the dimension of the opening 32b. For this reason, the first pattern 34 has a larger dimension in the second direction D2 than the second pattern 35. The dimensions of the first pattern 34 and the second pattern 35 in the second direction D2 are set to dimensions that can be recognized by the light detection unit 40 of the encoder.

  As described above, in the track region 30, two types of the first pattern 34 and the second pattern 35 having different lengths in the second direction D <b> 2 are formed as the optical pattern 33. Due to the difference in length (area difference) in the second direction D2 of the optical pattern 33, the amount of light reflected by one first pattern 34 is reflected by one second pattern 35 in the second direction D2. More than the amount of light emitted. In the example shown in FIG. 1B, from the left to the right in the figure, there are four first patterns 34, eight second patterns 35, four first patterns 34, and four second patterns 35. Twelve first patterns 34 are arranged side by side.

  For example, 512 optical patterns 33 including the first pattern 34 and the second pattern 35 are formed over one circumference of the track region 30. The optical pattern 33 is used as an incremental pattern, for example. As shown in FIG. 1B, a plurality of the first patterns 34 and the second patterns 35 are arranged together in the first direction D1. This grouped arrangement is used, for example, as an M-sequence absolute pattern.

  In FIG. 2A, as shown in FIG. 1A, the light detection unit 40 irradiates the track region 30 with detection light while the scale S is rotated, receives reflected light, and performs photoelectric conversion. It is a graph which shows the output detection signal. The horizontal axis of the graph shown in FIG. 2A indicates the time axis, and the vertical axis of the graph indicates the signal strength of the detection signal. The detection signal here is a detection signal obtained by integrating detection values of light reflected by one reflected light pattern 33 in a direction corresponding to the second direction D2. Note that the graph shown in FIG. 2A shows the detection results obtained when the portion shown in FIG. 1B is detected in one round of the track area 30. In FIG. 2A, the time for detecting four optical patterns 33 is shown as one period.

  As shown in FIG. 2A, the light detection unit 40 obtains a waveform detection signal as the optical pattern 33 moves, but the signal (first signal) obtained by the light reflected by the first pattern 34. ) And a signal (second signal) obtained by the light reflected by the second pattern 35 are detected with different peak values. That is, the light detection unit 40 can detect two types of signals, the first signal and the second signal. Thus, the dimension of the first pattern 34 formed on the scale S and the dimension of the second pattern 35 can be identified by the light detection unit 40.

  In the graph of FIG. 2A, the following signals are detected. In the first period t1, four first signals are detected. In the second period t2 and the third period t3, four second signals are detected. In the fourth period t4, four first signals are detected. In the fifth period t5, four second signals are detected. Four first signals are detected in each of the sixth period t6, the seventh period t7, and the eighth period t8. The signal value S1 of the first signal is larger than the signal value S2 of the second signal. Further, the cycle T1 of the first signal is equal to the cycle T2 of the second signal.

  FIG. 2B is a graph showing an output result when the detection signal shown in FIG. 2A is processed by a low-pass filter. In FIG. 2B, as in FIG. 2A, the horizontal axis of the graph indicates the time axis, and the vertical axis of the graph indicates the signal strength of the output signal. As shown in FIG. 2B, a low-frequency signal graph is obtained by the low-pass filter. This low frequency signal becomes a signal value S11 in the first period t1, the fourth period t4, the sixth period t6, the seventh period t7, and the eighth period t8 in which the first signal is detected. The signal value S21 is used in the second period t2, the third period t3, and the fifth period t5 in which the second signal is detected. The timing at which the period during which the first signal S11 is detected and the period during which the second signal S21 is detected coincides with the timing at which the first pattern 34 and the second pattern 35 are switched.

  Here, when the signal value S11 of the low frequency signal is “1” and the signal value S21 of the low frequency signal is “0”, the low frequency signal has the same output as the digital signal “10010111” along the time axis. can get. As described above, since the arrangement of the first pattern 34 and the second pattern 35 of the optical pattern 33 is set to be an M-sequence signal, by using a low-frequency signal (digital signal), absolute Position information can be obtained. That is, a signal similar to the signal used for the absolute encoder is obtained.

  In the present embodiment, a low frequency signal is formed by using four optical patterns 33 as one set. However, the present invention is not limited to this. For example, two, three, or five or more sets are formed as one set. It may be formed. Note that when a total of 512 optical patterns 33 are formed in the track region 30, for example, there are 128 patterns for forming low-frequency signals. 2A shows the case where the peak values of the first signal S1 and the second signal S2 are the same, but they may not be the same. For example, the signal values of the first signal S1 and the second signal S2 may vary as long as the low-frequency signal is generated by the low-pass filter.

  FIG. 2C is a graph showing an output result when the detection signal shown in FIG. 2A is processed by a high pass filter. In FIG. 2C, the horizontal axis of the graph shows the time axis, and the vertical axis of the graph shows the magnitude of the signal intensity value of the output signal, as in FIG. As shown in FIG. 2C, a high-frequency signal graph is obtained by the high-pass filter. This high-frequency signal is obtained by outputting the high-frequency portion of the first signal and the second signal. The high-frequency signal has four peak values in all the periods from the first period t1 to the eighth period t8, and a waveform signal having a period T3 is output with the peak value being the signal value S22. Note that the period T3 is equal to the period T1 or the period T2.

  Based on this high frequency signal, incremental information in the first direction D1 of the optical pattern 33 is obtained. That is, a signal similar to the signal used for the incremental encoder is obtained. As described above, even when the signal values of the first signal S1 and the second signal S2 vary, the high-frequency signal shown in FIG. 2C can be obtained by processing with a high-pass filter.

  Thus, according to the first embodiment, the first pattern 34 and the second pattern 35 are arranged in a line in the first direction D1 in one track region 30, and the first pattern 34 and the second pattern 35 are By changing the length in the second direction D2, it is possible to generate both absolute position information and incremental information as described above. Therefore, it is not necessary to secure a plurality of track areas 30 in the scale S, and the scale S can be reduced. Thereby, an encoder can be reduced in size. Further, since the alignment with the light detection unit 40 only needs to correspond to one track region 30, the accuracy of attaching the scale S to the shaft portion or the like can be relaxed, and the attaching operation can be easily performed.

<Method for producing scale S>
Next, a method for manufacturing the scale S configured as described above will be described. 3A to 3E are perspective views showing the manufacturing process of the scale S. FIG. 3A to 3E show a state in which a part of a region where the optical pattern 33 is formed is extracted from the entire scale S for convenience of explanation.

  First, as shown in FIG. 3A, the light reflecting layer 31 is formed on the surface of the base material 10 c constituting the substrate 10. The light reflecting layer 31 is formed, for example, by depositing aluminum using a technique such as sputtering deposition or vacuum deposition. Moreover, the light reflection layer 31 may be formed using a technique such as a plating method or an electrolytic oxidation method according to the material of the surface of the substrate 10c. After forming the light reflecting layer 31, the surface 31a of the light reflecting layer 31 is mirror-finished. As the mirror finish, for example, a method such as polishing or grinding can be applied.

  Next, as illustrated in FIG. 3B, a resist layer R is formed on the surface 31 a of the light reflecting layer 31. For example, the resist layer R is formed by applying a resist to the surface 31 a of the light reflecting layer 31 using a coating device such as a spin coater or an ink jet device. As the resist, a positive type or negative type photosensitive material is used. The resist layer R may be subjected to heat treatment (pre-baking) under predetermined conditions after the resist is applied. The pre-bake conditions can be appropriately set according to the type of resist used.

  Next, for example, an image of a predetermined pattern is projected onto the resist layer R using an exposure apparatus or the like, and the resist layer R is exposed (exposure processing). After the exposure processing, for example, development is performed using a predetermined developer by a developer or the like. By this development process, resist patterns Ra and Rb are formed on the surface 31a of the light reflecting layer 31, as shown in FIG. The surface 31a of the light reflecting layer 31 is exposed at a portion where the resist patterns Ra and Rb are not present. The resist pattern Ra is formed at a position corresponding to the first pattern 34. The resist pattern Rb is formed at a position corresponding to the second pattern 35. The resist patterns Ra and Rb are formed in a line at a predetermined interval in the first direction D1. The resist pattern Ra has a dimension in the second direction D2 larger than that of the resist pattern Rb.

  After development, if necessary, the resist patterns Ra and Rb may be subjected to heat treatment (post-bake) under predetermined conditions. Post bake conditions can be set as appropriate according to the type of resist used. Further, if necessary, the base material 10c on which the resist patterns Ra and Rb are formed and the entire surface 31a of the light reflecting layer 31 may be immersed in the treatment liquid to perform the chemical conversion treatment. When the chemical conversion treatment is performed, the entire surface 31a of the base material 10c and the light reflection layer 31 is immersed in a neutralization treatment liquid, and the exposed portions of the surface 31a of the light reflection layer 31 excluding the resist patterns Ra and Rb are inside. To sum up.

  Next, as illustrated in FIG. 3D, the reflection suppressing layer 32 is formed on the exposed portion of the surface 31 a of the light reflecting layer 31 excluding the resist patterns Ra and Rb. The reflection suppression layer 32 is formed, for example, by depositing chromium using a technique such as sputtering deposition, vacuum deposition, plating, or electrolytic oxidation.

  After forming the reflection suppressing layer 32, the resist patterns Ra and Rb are removed. Examples of the method for removing the resist patterns Ra and Rb include a method of immersing the base material 10c on which the resist patterns Ra and Rb are formed in a resist stripping solution. The resist stripping solution can be appropriately selected and used depending on the type of resist used. Further, the immersion treatment conditions can be appropriately set according to the type of resist stripping solution used.

  By removing the resist patterns Ra and Rb, an optical pattern 33 is formed as shown in FIG. In the region where the resist pattern Ra has been formed, the opening 32a is formed, the surface 31a of the light reflecting layer 31 is exposed, and the first pattern 34 as the optical pattern 33 is formed. Similarly, in the region where the resist pattern Rb has been formed, an opening 32b is formed, the surface 31a of the light reflecting layer 31 is exposed, and a second pattern 35 as the optical pattern 33 is formed.

<First Modification>
In the first embodiment described above, the shape in which the first pattern 34 is integrated in the second direction D2 has been described as an example. However, the shape is not limited to this, and the first pattern 34 is divided in the second direction D2. May be. FIG. 4A is a perspective view showing an example of a scale according to the first modification. In FIG. 4A, a part of the track area 30A is shown. About another structure, it is the same as that of the scale S shown in FIG.

  As shown in FIG. 4A, a first pattern 34A and a second pattern 35A are formed in a line in the first direction D1 in the track region 30A. The first pattern 34A is divided into three in the second direction D2. The first pattern 34A has a first region 34a, a second region 34b, and a third region 34c.

  The first region 34a, the second region 34b, and the third region 34c are formed in the same shape and size as each other, and are arranged in a line in the second direction D2. The first region 34a, the second region 34b, and the third region 34c are each formed in a rectangular shape, but are not limited thereto, and may be other shapes such as a triangle, a circle, and an ellipse, for example. However, the shape may be a part of which is changed, such as a shape with rounded corners. The first pattern 34A is not limited to the configuration divided into three in the second direction D2, and may be configured to be divided into two or four or more in the second direction D2. The first pattern 34A may be divided in the first direction D1.

  The second pattern 35A is formed to have the same shape and size as one of the first region 34a to the third region 34c. The second pattern 35A is arranged at the same position as the second region 34b in the second direction D2. However, the size and position of the second pattern 35A relative to the first region 34a and the like can be arbitrarily set.

  Also in the scale of the first modified example, similarly to the first pattern 34 and the second pattern 35 shown in FIG. 1, the detection signal can be separated into a low frequency signal and a high frequency signal, and absolute position information and incremental information. Both can be generated. The manufacturing method of the first modification is almost the same as the manufacturing method of the scale S shown in FIG. Also, the first pattern 34A may be divided in the same manner as the second pattern 35A.

<Second Modification>
In the first embodiment and the first modification described above, the configuration in which the centers of the first pattern 34 and the second pattern 35 are aligned in the second direction D2 is arranged in the first direction D1 as an example. However, the present invention is not limited to this, and a configuration may be adopted in which the center of the first pattern 34 and the center of the second pattern 35B in the second direction D2 are biased. FIG. 4B is a perspective view showing an example of a scale according to the second modification. In FIG. 4B, a part of the track area 30B is shown. About another structure, it is the same as that of the scale S shown in FIG.

  As shown in FIG. 4B, the first pattern 34 and the second pattern 35B are arranged so that the ends on the rotation axis AX side of the scale S are aligned in the second direction D2. Note that the present invention is not limited to this configuration, and the first pattern 34 and the second pattern 35B may be arranged such that the ends on the outer peripheral side of the scale S are aligned in the second direction D2. In addition, the configuration is not limited to the configuration in which the end portions are aligned, and the center of the first pattern 34 and the center of the second pattern 35B may be configured to be shifted in the second direction D2.

  Also in the scale of the second modified example, the detection signal can be separated into a low frequency signal and a high frequency signal as in the first pattern 34 and the second pattern 35 shown in FIG. Both can be generated. The manufacturing method of the second modification is almost the same as the manufacturing method of the scale S shown in FIG.

<Third Modification>
In the first embodiment and the first and second modifications described above, the opening 32a for forming the first pattern 34 and the opening 32b for forming the second pattern 35 have different dimensions in the second direction D2. The structure formed is described as an example. However, the present invention is not limited to this. The pattern of the opening of the reflection suppressing layer 32 is the same, and the dimension in the second direction D2 differs depending on the film formed thereon. The structure to be able to be used may be sufficient. FIG. 5A is a perspective view showing an example of a scale according to the third modification. FIG.5 (b) is sectional drawing along the BB line of (a). FIG. 5 shows a part of the track area 30C. About another structure, it is the same as that of the scale S shown in FIG.

  As shown in FIG. 5A, openings 32a and 32c having the same dimensions in the first direction D1 and the second direction D2 are arranged side by side in the first direction D1 in the track region 30C. In the surface 31 a of the light reflecting layer 31, the region exposed from the opening 32 a is the first pattern 34 as in the above-described embodiment.

On the other hand, in the region exposed from the opening 32c in the surface 31a, both end portions in the second direction D2 are covered with the antireflection films 36 (36a, 36b). The antireflection film 36 is, for example, a single layer film such as magnesium fluoride (MgF ₂ ), a multilayer film in which silicon (Si) and molybdenum (Mo) are stacked, a metal film such as chromium, etc. May be used. As shown in FIG. 5A, the opening 32 c is prevented from partially reflecting the surface 31 a by the antireflection film 36. As a result, the region surrounded by the opening 32 c and the antireflection film 36 becomes the second pattern 35 </ b> C in which the second direction D <b> 2 is shorter than the first pattern 34.

  As shown in FIG. 5B, the dimension L2 in the second direction D2 of the second pattern 35C is smaller than the dimension L1 in the second direction D2 of the opening 32c by the antireflection films 36 at both ends. ing. The dimension L1 of the opening 32c is equal to the dimension of the opening 32a in the second direction D2. As described above, after forming the openings so that the plurality of openings 32a and 32c having the same dimension in the second direction D2 are aligned in the first direction D1, the openings (32c) where the second pattern 35C is to be formed. ) Is covered with the antireflection film 36, the dimension of the second pattern 35C in the second direction D2 can be adjusted. Thereby, the 1st pattern 34 and the 2nd pattern 35C from which the dimension of the 2nd direction D2 differs can be formed easily.

  However, the portion covering the opening 32c with the antireflection film 36 is not limited to that shown in FIG. For example, one end of the opening 32c may be covered, or the center portion may be covered leaving both end portions of the opening 32c. Further, instead of forming the antireflection film 36, a part of the surface 31a of the light reflecting layer 31 exposed through the opening 32c may be roughened to reduce the reflectance. For roughening, for example, sand blasting or etching is used.

  Also in the scale of the third modified example, similarly to the first pattern 34 and the second pattern 35 shown in FIG. 1, the detection signal can be separated into a low frequency signal and a high frequency signal, and absolute position information and incremental information are obtained. Both can be generated. In the manufacturing method of the third modified example, the antireflection film 36 is patterned in addition to the manufacturing method of the scale S shown in FIG. For the patterning of the antireflection film 36, for example, techniques such as sputtering deposition using a metal mask and vacuum deposition are used.

  The third modification may be formed by, for example, forming an antireflection film 36 on a part of a conventional existing incremental encoder scale and changing the length of a part of the optical pattern. Good. Further, as the antireflection film 36, a film with adjusted transmittance may be used.

<Encoder>
The encoder according to the embodiment will be described. FIG. 6 is a cross-sectional view illustrating an example of an encoder according to the embodiment. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. As shown in FIG. 6A, the encoder EC includes a scale (encoder scale) S, a main body B, and a controller CONT. As the scale S, the scale S of the first embodiment described above is used. The scale S is fixed to a shaft portion SF such as a rotary motor and rotates integrally with the shaft portion SF. The main body B is fixed to a non-rotating part BD, such as a casing of a rotary motor, and has a housing 39 and a light detection part 40. The light detection unit 40 detects light through the optical pattern 33 described above. The housing 39 may include an adjustment mechanism for adjusting the position of the light detection unit 40.

  FIG. 6B is a plan view illustrating an example of the light detection unit 40. As shown in FIG. 6B, the light detection unit 40 has a chip substrate 40a formed in a rectangular shape in plan view. A light emitting unit (illuminating unit) 41, a light receiving unit 42, and a control circuit 43 are formed on the chip substrate 40a.

  The light emitting unit 41 illuminates the above-described optical pattern 33 with detection light. The light emitting unit 41 is disposed, for example, at the center of the chip substrate 40a. The light emitting unit 41 includes a light emitting element 41a, a connection unit 41b, and a cathode electrode 41c, and further includes an anode electrode (not shown) and the like. The light emitting element 41a has a light emission region 41d. The light emission region 41d is formed so as to emit laser light having a predetermined wavelength in one direction or a plurality of directions. The connection portion 41b and the cathode electrode 41c are connected by, for example, a lead wire.

The light receiving unit 42 receives light via the optical pattern 33. In the present embodiment, the reflected light from the optical pattern 33 is received. The light receiving unit 42 includes a plurality of light receiving elements 42a. For example, a photodiode is used as the light receiving element 42a. The light receiving element 42a may be a one-dimensional sensor (line sensor) or a two-dimensional sensor (image sensor). When a two-dimensional sensor is used as the light receiving element 42a, detection with higher accuracy is possible. Examples of the two-dimensional sensor include a CCD (Charge Coupled Device) and a CMOS (Complementary).
Metal Oxide Semiconductor) image sensors are used. The light receiving element 42a can identify a dimensional difference in the second direction D2 between the first pattern 34 and the second pattern 35 formed on the scale S.

  The light receiving elements 42a are formed long in one direction (second direction D2), and a plurality of the light receiving elements 42a are arranged in the short direction (first direction D1). The arrangement of the light receiving elements 42a (the positions in the first direction D1 and the second direction D2) corresponds to the arrangement of the optical pattern 33. In the present embodiment, since the track regions 30 are arranged in a row, the light receiving elements 42a are provided in only one row correspondingly. The dimension of the light receiving element 42a that can receive light in the second direction D2 is formed corresponding to at least the dimension of the first pattern 34 in the longitudinal direction (second direction D2). The number of the light receiving elements 42 a can be appropriately changed according to the configuration of the optical pattern 33.

  FIG. 7 is a block diagram showing a control circuit 43 which is an example of a circuit configuration of the chip substrate 40a. As shown in FIG. 7, the chip substrate 40 a is formed to include an amplifier 44, a low-pass filter 45, a high-pass filter 46, comparators 47 and 48, and a processing circuit 49.

  The amplifier 44 amplifies the detection signal in the light receiving element 42 a and transmits it to the low pass filter 45 and the high pass filter 46. The low pass filter 45 removes a high frequency component from the signal from the amplifier 44 and transmits the signal to the comparator 47. The high pass filter 46 removes a low frequency component from the signal from the amplifier 44 and transmits the signal to the comparator 48. The low-pass filter 45 corresponds to the generation of the low frequency signal shown in FIG. The high pass filter 46 corresponds to the generation of the high frequency signal shown in FIG.

  The comparator 47 receives the signal transmitted from the low-pass filter 45, generates a binarized incremental signal INC, and transmits the incremental signal INC to the processing circuit 49. The comparator 48 receives the signal transmitted from the high pass filter 46, generates a binarized absolute signal ABS, and transmits the absolute signal ABS to the processing circuit 49.

  The processing circuit 49 generates one rotation information ST based on the interpolation incremental signal INC received from the comparator 47 and the absolute signal ABS received from the comparator 48. For example, the processing circuit 49 outputs position information including the single rotation information ST to the control unit CONT, for example, by a serial communication method or the like in response to a request from the control unit CONT. The control circuit 43 in the present embodiment is configured to include the amplifier 44, the low-pass filter 45, the high-pass filter 46, the comparators 47 and 48, and the processing circuit 49. However, the control circuit 43 may not include the processing circuit 49, for example. . Further, the single rotation information ST in the present embodiment is absolute position information, but may be relative position information.

  In the encoder EC configured as described above, the light detection unit 40 is arranged so that the detection signal of the track area 30 falls within the standard. For example, compared to a scale in which the track area 30 is provided in two rows, The position information can be detected with high accuracy by preventing the detection accuracy of the position information from deteriorating due to a change with time or an impact. Further, the encoder EC can easily attach the scale S to the shaft portion SF and install the light detection unit 40 to the non-rotating portion BD. Further, since the scale S can be reduced, the encoder EC can be reduced in size. The effect of such an encoder EC is the same in other embodiments and modifications described below.

Second Embodiment
A scale according to the second embodiment will be described. In the first embodiment and the first to third modifications described above, a configuration in which the length (area) of the optical pattern 33 in the second direction D2 is different between the first pattern 34 and the second pattern 35 is taken as an example. However, the present invention is not limited to this, and the first pattern and the second pattern have the same area of the optical pattern 33 and have different reflectivities so as to change the intensity of the reflected light. It may be.

  FIG. 8 is a perspective view illustrating an example of a scale according to the second embodiment. In FIG. 8, a part of the track area 30D is shown. About another structure, it is the same as that of the scale S shown in FIG. As shown in FIG. 8, in the track region 30D, openings 32a and 32c having the same dimensions in the first direction D1 and the second direction D2 are arranged side by side in the first direction D1. The region exposed from the opening 32 a is a part of the surface 31 a of the light reflecting layer 31, and this region is the first pattern 34.

  On the other hand, a region surrounded by the opening 32c is a second pattern 35D. In the second pattern 35 </ b> D, the surface 31 </ b> Da of the light reflection layer 31 </ b> D exposed from the opening 32 c is formed to have a lower reflectance than the surface 31 a of the light reflection layer 31. The light reflecting layer 31 and the light reflecting layer 31D may be made of the same material or different materials. When the light reflecting layer 31 and the light reflecting layer 31D are made of the same material, for example, the surface 31a of the light reflecting layer 31 is mirror-finished and the surface 31Da of the light reflecting layer 31D is not mirror-finished or roughened. By applying, the reflectance of the surface 31a and the surface 31Da can be made different.

  In the configuration illustrated in FIG. 8, the area of the first pattern 34 is equal to that of the second pattern 35 </ b> D, but the reflectance of the first pattern 34 is higher. For this reason, the intensity of the detection light reflected by the first pattern 34 is larger than the intensity of the detection light reflected by the second pattern 35D. Accordingly, similarly to the scale S of the first embodiment, a detection signal in which the first signal and the second signal shown in FIG. 2 are mixed can be acquired. As a result, both absolute position information and incremental information can be obtained by generating a low frequency signal and a high frequency signal, respectively.

  According to the scale of the second embodiment, both the absolute position information and the incremental information can be acquired using the optical pattern 33 arranged in a line, as in the scale S shown in FIG. Note that the scale manufacturing method according to the second embodiment is substantially the same as the scale S manufacturing method shown in FIG. 3, and the light reflection layer 31 and the light reflection layer 31D are formed, and the reflection suppression layer 32 is formed. Pattern. Moreover, you may make it vary the length of the 2nd direction D2 in the 1st pattern 34 and 2nd pattern 35D of 2nd Embodiment.

<Fourth Modification>
In the second embodiment described above, the reflectance of both is changed by forming the light reflecting layer 31 and the light reflecting layer 31D. However, the present invention is not limited to this, and the first pattern and the second pattern are not limited thereto. The same reflection layer 31 may be used, and the antireflection film 37 may have a different reflectance. Fig.9 (a) is a perspective view which shows an example of the scale which concerns on a 4th modification. FIG. 9B is a cross-sectional view taken along the line CC in FIG. FIG. 9 shows a part of the track area 30E. About another structure, it is the same as that of the scale S shown in FIG.

As shown in FIG. 9A, in the track region 30E, the opening 32c for forming the second pattern 35E is covered with an antireflection film 37. The antireflection film 37 is, for example, a single-layer film such as magnesium fluoride (MgF ₂ ), or a multilayer in which silicon (Si) and molybdenum (Mo) are stacked, as in the third modification described above. Any of a film and a metal film such as chromium may be used. By covering the second pattern 35E with the antireflection film 37, the reflectance of the second pattern 35E is smaller than the reflectance of the first pattern 34. In the case where the antireflection film 37 is a multilayer film as described above, it can be set to a desired reflectance by adjusting the number of layers and the thickness of the Si layer and the Mo layer.

  As shown in FIG. 9B, although the area of one first pattern 34 and one second pattern 35E are equal, the antireflection film 37 increases the reflectance of the first pattern 34. For this reason, the intensity of the detection light reflected by the first pattern 34 is larger than the intensity of the detection light reflected by the second pattern 35E.

  In the fourth modification, the optical patterns 33 having the same area and reflectance are formed in a row in the first direction D1, and then the signal value obtained by the light detection unit 40 of the plurality of optical patterns 33 is to be reduced. That is, the track region 30E can be formed by covering the portion corresponding to the second pattern 35E with the antireflection film 37 for adjusting the reflectance.

  According to the scale of the fourth modified example, both the absolute position information and the incremental information can be acquired using the optical patterns 33 arranged in a line, as in the second embodiment. In the fourth modification, the entire second direction D2 of the optical pattern 33 is covered with the antireflection film 37, so that a part of the second direction D2 of the optical pattern 33 is covered as in the third modification. Compared to the configuration, the position for patterning the antireflection film 37 can be easily adjusted. The fourth modification may be formed, for example, by coating a part of a conventional existing incremental encoder scale with an antireflection film 37 and changing the reflectance with a part of the optical pattern 33. . Further, as the antireflection film 37, a film with adjusted transmittance may be used.

<Third Embodiment>
A scale according to the third embodiment will be described. In each of the above-described embodiments and modifications, the configuration of the scale capable of acquiring absolute position information and incremental information has been described as an example. However, the present invention is not limited to this, and in addition to absolute position information and incremental information. For example, it is possible to acquire multi-rotation information. FIG. 10A is a plan view showing an example of a scale according to the third embodiment. FIG. 10 shows a part of the track area 30F. About another structure, it is the same as that of the scale S shown in FIG.

  As shown in FIG. 10A, a third pattern 38 is formed in the track region 30F as the optical pattern 33 in addition to the first pattern 34 and the second pattern 35. The third pattern 38 is provided in at least one place in the track area 30F. The third pattern 38 is larger in dimension in the second direction D2 by L3 than the first pattern 34. The third pattern 38 has a larger optical pattern area than the first pattern 34. For this reason, the amount of light reflected by the third pattern 38 is larger than the amount of light reflected by the first pattern 34 in the second direction D2.

  FIG. 10B is a graph showing detection signals when the track area 30F is irradiated with detection light while the scale SA is rotated, and reflected light is detected by the light detection unit 40F (see FIG. 11). The horizontal axis of the graph indicates the time axis, and the vertical axis of the graph indicates the signal strength of the detection signal. Note that the graph shown in FIG. 10B shows the detection results obtained when the portion shown in FIG. 10A is detected in one round of the track area 30F.

  As shown in FIG. 10B, the light detection unit 40F detects the third signal having the signal value S3 in addition to the first signal having the signal value S1 and the second signal having the signal value S2. The third signal is a detection result of the light reflected by the third pattern 38. When the light quantity reflected by the third pattern 38 is accumulated in the second direction D2, the light quantity reflected by the first pattern 34 is larger than the light quantity reflected by the first pattern 34. Therefore, the signal value S3 of the third signal is The value is larger than the signal value S1. By counting the third signal of the signal value S3, a function as a multi-rotometer that detects how many times the scale SA has rotated is added.

  According to the scale SA of the third embodiment, not only absolute position information and incremental information but also multi-rotation information can be acquired by a single row of the optical pattern 33. Therefore, it is not necessary to provide a conventional magnetic multi-rotometer, and the encoder can be miniaturized. The method for manufacturing the scale SA according to the third embodiment is substantially the same as the method for manufacturing the scale S shown in FIG. The length L3 of the third pattern 38 can be arbitrarily set as long as it can be identified from the first pattern 34.

  Further, as shown in FIG. 10A, the third pattern 38 is not limited to be formed, and for example, two or more third patterns 38 may be formed side by side in the track 30F. Good. Further, the third pattern 38 may be formed at regular intervals with, for example, several first patterns 34 interposed therebetween. Thereby, the rotation direction of the scale SA can be detected by measuring the interval at which the third signal is output. Further, the length of the third pattern 38 in the second direction D2 is not limited to changing the length of the third pattern 38 with respect to the first pattern 34 or the second pattern 35. For example, the length of the third pattern 38 in the second direction D2 The height may be the same as that of the first pattern 34, and the reflectance may be larger or smaller than that of the first pattern 34.

<Fifth Modification>
The light detection unit according to the fifth modification will be described. FIG. 11 is a plan view illustrating an example of the light detection unit according to the fifth modification. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. As shown in FIG. 11, the light detection unit 40F includes a multi-rotation detection circuit 43F in addition to the light emitting unit 41, the light receiving unit 42, and the control circuit 43. The light detection unit 40F employs a configuration corresponding to the scale SA of the third embodiment shown in FIG.

  The multi-rotation detection circuit 43F detects the multi-rotation information of the scale SA by counting the number of times the third signal shown in FIG. 10B is detected. The multi-rotation information detected by the multi-rotation detection circuit 43F is transmitted to the control unit CONT together with absolute position information and incremental information generated by the control circuit 43. As the light receiving unit 42, one that can correspond to the length of the third pattern 38 in the second direction D2 is used.

  As described above, according to the light detection unit 40F, the multi-rotation information can be detected by the light receiving unit 42 only by including the multi-rotation detection circuit 43F. Therefore, it is not necessary to mount the light detection unit 40F, a magnetic sensor, or the like, and the encoder can be reduced in size. The light reflected by the third pattern 38 is not limited to being received by the light receiving unit 42, and part or all of the light reflected by the third pattern 38 may be received by another sensor different from the light receiving unit 42. Good.

<Fourth embodiment>
A scale according to the fourth embodiment will be described. In each of the above-described embodiments and modifications, the configuration in which one track area 30 or the like is provided in the scale has been described as an example. However, the present invention is not limited to this, and a plurality of track areas are included in the scale. The provided structure may be sufficient. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. FIG. 12 is a perspective view illustrating an example of the scale SB according to the fourth embodiment.

  As shown in FIG. 12, the scale SB has two track regions 30 and 30G on the first surface 10a of the substrate 10. The track area 30, which is one of the two, has the same configuration as that of the first embodiment. The track region 30 may have the same configuration as any of the track regions 30A to 30F shown in other embodiments or modifications.

  Inside the track area 30, a backup track area 30G is provided. The track area 30G has an optical pattern 33G. The optical pattern 33G has a first pattern 34G and a second pattern 35G. The arrangement of the first pattern 34G and the second pattern 35G in the first direction D1 is the same as the arrangement of the first pattern 34 and the second pattern 35 in the track region 30. However, since the track region 30G is disposed inside the track region 30, the optical pattern 33G is disposed in a state of being reduced in the first direction D1 with respect to the optical pattern 33.

  According to the fourth embodiment, even when one of the track areas 30 and 30G becomes unusable due to damage or the like, the function of the encoder can be maintained by using the other. Note that it is only necessary to ensure the arrangement of the same optical patterns 33 in the track areas 30 and 30G. Therefore, the optical patterns 33 having the same form are not used in the track areas 30 and 30G, and are different in the track areas 30 and 30G. An optical pattern 33 in the form may be used.

<Sixth Modification>
A light detection unit according to a sixth modification will be described. FIG. 13 is a plan view illustrating an example of a light detection unit according to a sixth modification. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. As illustrated in FIG. 13, the light detection unit 40 </ b> G includes a second light receiving unit 42 </ b> G in addition to the light emitting unit 41, the light receiving unit 42, and the control circuit 43. The light detection unit 40G has a configuration corresponding to the scale SB of the fourth embodiment shown in FIG.

  Similar to the light receiving unit 42, the second light receiving unit 42G includes a plurality of light receiving elements 42Ga. In the second light receiving portion 42G, the light receiving element 42Ga is arranged in a state of being reduced in the first direction D1 so as to correspond to the track region 30G inside the track region 30. The same number of light receiving elements 42a and light receiving elements 42Ga are provided.

  In addition, the light emission region 41d of the light emitting element 41a in the light emitting unit 41 is disposed between the light receiving unit 42 and the second light receiving unit 42G in the second direction D2. Accordingly, the detection light can be emitted from the light emission region 41d to both the optical pattern 33 in the track region 30 and the optical pattern 33G in the track region 30G. However, the track region 30 and the track region 30G may be individually irradiated with detection light.

  The control circuit 43 always obtains the detection result by the light receiving unit 42 and the detection result by the second light receiving unit 42G, and compares them, and if one of the detection results is different, one of them is out of order. You may judge. Which one has failed may be estimated using previous detection results with different detection results.

  As described above, the light detection unit 40G includes the light receiving unit 42 and the second light receiving unit 42G that detect the optical patterns 33 and 33G of the track regions 30 and 30G provided on the scale SB, and thus either one is backed up. Can be used for Accordingly, even if one of the track areas 30 and 30G or one of the light receiving unit 42 and the second light receiving unit 42G is damaged and becomes unusable, position detection is continuously performed by using the other. be able to.

<Drive device>
The drive device according to the embodiment will be described. FIG. 14 is a diagram illustrating an example of an electric motor device MTR as an example of the drive device according to the embodiment. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. As shown in FIG. 14, the motor device MTR includes a shaft portion SF, a main body portion (drive portion) BD that rotationally drives the shaft portion SF, and an encoder EC that detects rotation information of the shaft portion SF. .

  The shaft portion SF has a load side end portion SFa and an anti-load side end portion SFb. The load side end portion SFa is connected to another power transmission mechanism such as a speed reducer. The scale S is fixed to the non-load side end portion SFb via the fixing portion 20. An encoder EC is attached so as to correspond to the scale S. As the scale S and the encoder EC, the configurations shown in the above embodiments and modifications can be used.

  According to this motor device MTR, since the miniaturized encoder EC is mounted, the entire motor device MTR can be miniaturized. Further, since the small encoder EC is attached to the non-load side end portion SFb, the protrusion from the motor device MTR is reduced, and the motor device MTR can be installed in a small space. Although the motor device MTR has been described as an example of the drive device, the drive device is not limited thereto, and may be another drive device having a shaft portion using hydraulic pressure or pneumatic pressure.

<Robot device>
A robot apparatus according to an embodiment will be described. FIG. 15 is a perspective view illustrating an example of the robot apparatus RBT according to the embodiment. FIG. 15 schematically shows the configuration of a part (joint portion) of the robot apparatus RBT. In the following description, components that are the same as or equivalent to those in the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted or simplified. As shown in FIG. 15, the robot apparatus RBT includes a first arm AR1, a second arm AR2, and a joint portion JT. The first arm AR1 and the second arm AR2 pass through the joint portion JT. Connected to each other.

  The first arm AR1 includes an arm portion 101 and bearings 101a and 101b. The second arm AR2 is provided with an arm portion 102 and a connection portion 102a. In the joint portion JT, the connection portion 102a is disposed between the bearings 101a and 101b. The connecting portion 102a is provided integrally with the shaft portion SF2. In the joint portion JT, the shaft portion SF2 is inserted into both the bearings 101a and 101b. The end of the shaft portion SF2 on the side inserted into the bearing 101b passes through the bearing 101b and is connected to the speed reducer RG.

  The reduction gear RG is connected to the motor device MTR, and reduces the rotation of the motor device MTR to, for example, 1/100 and transmits it to the shaft portion SF2. As the motor device MTR, the motor device MTR shown in FIG. 14 is used. Although not shown in FIG. 15, the load side end portion SFa of the shaft portion SF of the motor device MTR is connected to the speed reducer RG. Further, the scale S of the encoder EC is attached to the non-load side end portion SFb of the shaft portion SF of the motor device MTR.

  When the robot device RBT configured as described above drives the motor device MTR to rotate the shaft portion SF, the rotation is transmitted to the shaft portion SF2 via the reduction gear RG. Due to the rotation of the shaft portion SF2, the connecting portion 102a rotates integrally, whereby the second arm AR2 rotates relative to the first arm AR1. At that time, the encoder EC detects the rotational position of the shaft portion SF and the like. Therefore, the rotational position of the second arm AR2 can be detected by using the output from the encoder EC.

  Thus, according to the robot apparatus RBT, since the small motor apparatus MTR is mounted, the entire robot apparatus RBT can be reduced in size. In addition, since the small encoder EC is provided, the protrusion from the joint portion JT is reduced, and the protrusion can be prevented from interfering with other devices. Note that the robot apparatus RBT is not limited to the above-described configuration. For example, the motor apparatus MTR can be mounted on various robot apparatuses having joints.

  The embodiment has been described above, but the present invention is not limited to the above description, and various modifications can be made without departing from the gist of the present invention. For example, in each of the above-described embodiments and modifications, the scale having a reflective optical pattern has been described as an example. However, the present invention is not limited to this, and the scale having a light-transmissive optical pattern, and the scale. It may be an encoder, a drive device, or a robot device using the above. In the light transmission type optical pattern, the second pattern 35 is shorter in length than the first pattern 34 in the second direction D2, or the first pattern 34 and the second pattern 35 have different transmittances. The In these light transmissive optical patterns, the same forms as those of the above-described embodiments and modifications can be applied.

  Moreover, in each above-mentioned embodiment and each modification, although it showed about the rotary encoder, it is not limited to this, For example, a linear encoder may be sufficient. In the case of a linear encoder, a moving member (movable element) moves in a linear direction by a linear guide (stator), and a scale is arranged along the linear guide. Note that the direction of the linear guide is the first direction D1. The light detection unit 40 is mounted on the moving member, and detects the position of the moving member with respect to the linear guide by detecting the optical pattern of the scale. The scale used here can be the same scale as in each of the above-described embodiments and modifications, with the first direction D1 as the linear direction.

  The encoder EC and the motor device MTR described above are not limited to the application to the robot device RBT, and may be applied to a rotary table provided in a machine tool such as a lathe.

  S, SA, SB ... scale, AX ... rotation axis, D1 ... first direction, D2 ... second direction, p ... pitch, EC ... encoder, SF ... shaft part, CONT ... control part, MTR ... motor device ( Drive device), RBT ... robot device, 10 ... substrate, 20 ... fixed part, 30, 30A-30F ... track area, 30G ... backup area, 33 ... optical pattern, 34 ... first pattern, 35, 35A-35G ... first 2 patterns, 36, 37 ... antireflection film (film part), 38 ... third pattern, 40 ... light detection part, 41 ... light emission part (illumination part), 42 ... light receiving part, 43 ... control circuit, 45 ... low pass filter 46 ... High-pass filter

Claims (17)

An encoder scale having an optical pattern that can be detected by a light detection unit,
The optical pattern is arranged in a line in a first direction, and has a first pattern having a predetermined length in a second direction intersecting the first direction, the first pattern, and the second direction. A second pattern having different lengths,
One of the first pattern and the second pattern is an encoder scale having position information of the optical pattern in the first direction.   2. The first pattern and the second pattern are each formed to have a length in the second direction in which the first pattern and the second pattern can be distinguished from each other in a detection signal from the light detection unit. Encoder scale as described. An encoder scale having an optical pattern that can be detected by a light detection unit,
The optical pattern includes a first pattern arranged in a line in a first direction and having a predetermined reflectance or transmittance, and a second pattern having a reflectance or transmittance different from that of the first pattern. Encoder scale.   The encoder scale according to claim 3, wherein one of the first pattern and the second pattern has position information of the optical pattern in the first direction.   5. The encoder scale according to claim 3, wherein one of the first pattern and the second pattern is covered with a film part that adjusts reflectance or transmittance.   The encoder scale according to any one of claims 1 to 5, wherein the first pattern and the second pattern have the same interval in the first direction. The optical pattern is formed on a substrate rotatable with respect to the light detection unit,
The encoder scale according to any one of claims 1 to 6, wherein the first direction is an annular direction centered on a rotation axis of the substrate.   The encoder scale according to claim 7, wherein the optical pattern includes a reference pattern indicating a reference position in one rotation.   The encoder scale according to claim 8, wherein the reference pattern is different in length in a second direction intersecting the first direction from other patterns.   The encoder scale according to claim 1, wherein a plurality of the optical patterns are arranged in parallel in the first direction.   The encoder scale according to any one of claims 1 to 10, further comprising a fixed portion fixed to the moving member to be measured. A method for manufacturing an encoder scale having an optical pattern that can be detected by a light detection unit,
Forming the optical pattern in a row in a first direction;
Forming a film part of a part of the optical pattern so that the lengths in the second direction intersecting the first direction are different from each other. A method for manufacturing an encoder scale having an optical pattern that can be detected by a light detection unit,
Forming the optical pattern in a row in a first direction;
A method for manufacturing an encoder scale, comprising: covering a part of the optical pattern with a film part for adjusting reflectance or transmittance. An encoder scale having an optical pattern;
A light detection unit for detecting light via the optical pattern,
The encoder in which the scale for encoders according to any one of claims 1 to 11 is used as the scale for encoders.   The encoder according to claim 14, further comprising an illumination unit that illuminates the optical pattern. A moving member, a drive unit that moves the moving member, and an encoder that is fixed to the moving member and detects position information of the moving member,
A drive device in which the encoder according to claim 14 or 15 is used as the encoder. A moving object, and a drive device that moves the moving object,
A robot apparatus using the driving apparatus according to claim 16 as the driving apparatus.

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