WO2014203314A1

WO2014203314A1 - Encoder, motor provided with encoder, and servo system

Info

Publication number: WO2014203314A1
Application number: PCT/JP2013/066619
Authority: WO
Inventors: 高田　裕司; 有永　雄司; 次郎村岡
Original assignee: 株式会社安川電機
Priority date: 2013-06-17
Filing date: 2013-06-17
Publication date: 2014-12-24
Also published as: JPWO2014203314A1

Abstract

[Problem] To provide an encoder, a motor provided with an encoder, and a servo system that are capable of enhancing detection accuracy. [Solution] An encoder (100) has a slit track (ST) having a plurality of reflecting slits (111) arranged along the circumferential direction (C) of a disk and has an optical module (130) capable of moving relative to the slit track (ST) in the circumferential direction (C) of the disk while opposing a portion of the slit track (ST). The optical module (130) has a light source (131) for irradiating light onto the opposing portion of the slit track (ST), a light receiving array (PA) having a plurality of light receiving elements (142) that are arranged along the circumferential direction (C) of the disk and receive reflected light reflected by each of the reflecting slits (111), and a slit array (SA) having a plurality of transmitting slits (166) that are disposed between the slit track (ST) and the light receiving array (PA), are arranged along the circumferential direction (C) of the disk, and transmit the reflected light (L1) reflected by each of the reflecting slits (111).

Description

Encoder, motor with encoder, and servo system

The disclosed embodiment relates to an encoder, a motor with an encoder, and a servo system.

For example, in Patent Document 1, a light source unit, a light receiving array including a plurality of light receiving elements arranged in an array, an optical grating irradiated with light from the light source unit, and a plurality of lights irradiated to the optical grating An encoder is described that includes a lens array configured by collecting a plurality of lenses that focus light directed to each light receiving element of the light receiving element, and a scale that is disposed to be relatively movable with a gap provided therebetween. ing.

JP 2004-28667 A

In the above prior art, the light directed to each light receiving element out of the light irradiated to the optical grating is focused by each lens of the lens array. However, noise is generated when scattered light or stray light incident from an angle different from the focused light is received by the light receiving element. Such noise causes a decrease in the position detection accuracy of the encoder, but was not taken into account in the prior art.

An object of the present invention is to provide an encoder, a motor with an encoder, and a servo system that can improve detection accuracy.

In order to solve the above problems, according to one aspect of the present invention, a slit track having a plurality of first slits arranged along a measurement direction;
An optical module capable of moving relative to the slit track in the measurement direction while facing a part of the slit track,
The optical module is
A light source configured to emit light to opposing portions of the slit track;
A light-receiving array having a plurality of light-receiving elements that are arranged along the measurement direction and each receive light subjected to the action of the first slit;
A slit array that is disposed between the slit track and the light receiving array and has a plurality of second slits that are arranged along the measurement direction and each transmit light that has been subjected to the action of the first slit. An encoder is provided.

In order to solve the above problem, according to another aspect of the present invention, a linear motor in which the mover moves with respect to the stator, or a rotary motor in which the rotor rotates with respect to the stator,
An encoder-equipped motor comprising: the encoder according to any one of claims 1 to 6 that detects at least one of a position and a speed of the mover or the rotor.

In order to solve the above problems, according to still another aspect of the present invention, a linear motor in which a mover moves with respect to a stator, or a rotary motor in which a rotor rotates with respect to a stator, and ,
The encoder according to any one of claims 1 to 6, which detects at least one of a position and a speed of the mover or the rotor;
There is provided a servo system comprising a control device configured to control the linear motor or the rotary motor based on a detection result of the encoder.

As described above, according to the present invention, detection accuracy can be improved.

It is explanatory drawing for demonstrating the outline of a structure of the servo system which concerns on one Embodiment. It is explanatory drawing for demonstrating the structure of the encoder which concerns on the same embodiment. It is explanatory drawing for demonstrating the disk which concerns on the same embodiment. It is explanatory drawing for demonstrating the optical module which concerns on the same embodiment. It is explanatory drawing for demonstrating the disk and optical module which concern on the same embodiment. It is explanatory drawing for demonstrating the light-receiving part and translucent member which concern on the embodiment. It is explanatory drawing for demonstrating the translucent member and deflection | deviation member which concern on the modification which provides a deflecting member in a translucent member. It is explanatory drawing for demonstrating the translucent member and deflection | deviation member which concern on the modification which provides a deflecting member in a translucent member. It is explanatory drawing for demonstrating the translucent member and deflection | deviation member which concern on the modification which forms a bubble wall around a deflection | deviation member.

Hereinafter, an embodiment will be described in detail with reference to the drawings.

<1. Servo system>
First, an outline of a configuration of a servo system according to the present embodiment will be described with reference to FIG.

As shown in FIG. 1, the servo system S according to this embodiment includes a servo motor SM (an example of a motor with an encoder) and a control device CT. The servo motor SM includes a motor M (an example of a rotary motor) and an optical encoder 100.

The motor M is an example of a power generation source that does not include the encoder 100. Although the motor M alone may be referred to as a servo motor, in this embodiment, a configuration including the encoder 100 is referred to as a servo motor SM. For convenience of explanation, a case where the motor with an encoder is a servo motor that is controlled so as to follow a target value such as position and speed will be described below, but the motor is not necessarily limited to the servo motor. The motor with an encoder includes a motor used other than the servo system as long as the encoder is attached, for example, when the output of the encoder is used only for display. The motor M includes a stator m1, a rotor m2 disposed inside the stator m1 and supported rotatably with respect to the stator m1, and a shaft SH coupled to the rotor m2. That is, the motor M is a so-called “inner rotor type” motor in which the rotor m2 is disposed inside the stator m1. The motor M is not limited to an inner rotor type motor. For example, the motor M may be a so-called “outer rotor type” motor in which a rotor is arranged outside the stator, or a so-called “flat rotor type” in which a rotor and a stator are arranged in the direction of the rotation axis. May be used. However, for convenience of explanation, a case where the motor M is an inner rotor type motor will be described below. One of the stator m1 and the rotor m2 functions as an armature, and the other functions as a field. The motor M outputs a rotational force by rotating the shaft SH around the rotation axis AX by rotating the rotor m2 relative to the stator m1.

The motor M is not particularly limited as long as it is a motor controlled based on data detected by the encoder 100 such as position data described later. The motor M is not limited to an electric motor that uses electricity as a power source. For example, the motor M is a motor using another power source such as a hydraulic motor, an air motor, or a steam motor. There may be. However, for convenience of explanation, a case where the motor M is an electric motor will be described below.

The encoder 100 is connected to a shaft SH on the opposite side (also referred to as “anti-load side”) of the motor M on the rotational force output side (also referred to as “load side”). The connection position of the encoder 100 is not particularly limited. For example, the encoder 100 may be connected to the shaft SH on the torque output side of the motor M, or may be connected to the shaft SH or the like via another mechanism such as a speed reducer, a rotation direction changer, or a brake. Good.

The encoder 100 detects the position (angle) of the shaft SH, thereby detecting the position of the rotor m2 (also referred to as “rotation angle”), and outputs position data representing the position. In addition to or instead of the position of the rotor m2, the encoder 100 is also referred to as the speed (also referred to as “rotational speed”, “angular speed”, etc.) and acceleration (“rotational acceleration”, “angular acceleration”, etc.) of the rotor m2. .) May be detected. In this case, the speed and acceleration of the rotor m2 can be detected, for example, by a process such as differentiating the position by 1st or 2nd order with respect to time or counting the detection signal for a predetermined time. However, for convenience of explanation, the following description will be made assuming that the physical quantity detected by the encoder 100 is a position.

The control device CT acquires the position data output from the encoder 100 and controls the driving of the motor M based on the position data. Therefore, in the present embodiment in which an electric motor is used as the motor M, the control device CT controls the driving of the motor M by controlling the current or voltage applied to the motor M based on the position data. Further, the control device CT acquires a higher control signal from the higher control device, and controls the motor M so that a rotational driving force capable of realizing the position or the like represented by the higher control signal is output from the shaft SH. It is also possible. In addition, when the motor M uses other power sources, such as a hydraulic type, an air type, and a steam type, the control apparatus CT controls the drive of the motor M by controlling supply of those power sources. Is possible.

<2. Encoder>
Next, the configuration of the encoder 100 according to the present embodiment will be described with reference to FIGS.

As shown in FIG. 2, the encoder 100 according to the present embodiment includes a disk-shaped disk 110 that is a detected medium that detects the position of the rotor m2, an optical module 130, and a position data generation unit 190. .

Here, for convenience of explanation of the configuration of the encoder 100, the following directions such as up and down are defined as follows. That is, the positive Z-axis direction that is the anti-load side direction in the rotation axis AX is defined as “up”, and the negative Z-axis direction that is the load side direction in the reverse rotation axis AX is defined as “down”. However, the positional relationship between the components of the encoder 100 is not limited to the concept of up and down. In addition, for the convenience of explanation, it is noted that other directions may be used for the directions determined here, or directions other than these may be used while being described as appropriate.

(2-1. Disc)
As shown in FIGS. 2, 3, and 5, the disk 110 is connected to the shaft SH so that the disk center O substantially coincides with the rotation axis AX, and the circumference of the disk 110 is rotated by the rotation of the shaft SH. It rotates in a direction C (in the direction of arrow C in FIG. 3; hereinafter also referred to as “disk circumferential direction C”). The disk circumferential direction C, which is the rotation direction of the disk 110, corresponds to an example of the measurement direction. The disk 110 can be made of glass, metal, resin, or the like. In the present embodiment, the disk 110 is described as an example of the detected medium. However, for example, other members such as the end face of the shaft SH can be used as the detected medium.

On the upper surface of the disk 110, a ring-shaped slit track ST centered on the disk center O is formed. The slit track ST has a plurality of reflective slits 111 (an example of a first slit) along the radial direction of the disk 110 (in the direction of arrow R in FIG. 3; hereinafter, also referred to as “disk radial direction R”). The slit track ST is configured by arranging a plurality of reflective slits 111 in a track shape at a predetermined pitch P along the disk circumferential direction C.

Each reflection slit 111 reflects light emitted from a light source 131 described later. The reflection slit 111 can be formed, for example, by applying a light reflecting material (for example, aluminum or the like) to a portion that reflects light on the upper surface of the disk 110 configured not to reflect light. is there. Further, the reflection slit 111 reduces the reflectivity by making a portion of the upper surface of the disk 110 made of a metal having high reflectivity that does not reflect light rough or by applying a low reflectivity material by sputtering or the like. May be formed. However, the formation method of the reflective slit 111 is not limited to the above example.

In the present embodiment, the plurality of reflective slits 111 are arranged so as to have an incremental pattern in the disk circumferential direction C. An incremental pattern is a pattern in which the reflective slits 111 are regularly repeated at a predetermined pitch. This incremental pattern represents the position of the rotor m2 for each pitch or within one pitch by the sum of electrical signals from one or more light receiving elements 142 described later.

(2-2. Optical module)
As shown in FIGS. 2 to 5, the optical module 130 is formed as a substrate BA. The substrate BA is fixed so as to be substantially parallel to the disk 110 and to face a part of the slit track ST. Accordingly, the optical module 130 moves relative to the slit track ST in the disk circumferential direction C as the disk 110 rotates. In the present embodiment, the case where the optical module 130 is formed as a substrate BA capable of reducing the thickness of the encoder 100 or facilitating manufacturing will be described. However, the optical module 130 is not necessarily configured in a substrate shape. There is no need. Such an optical module 130 includes a light source 131, a light receiving unit 140, and a translucent member 160.

(2-2-1. Light source)
The light source 131 is provided on the lower surface of the substrate BA (on the side facing a part of the slit track ST). In this example, the light source 131 is disposed on the lower surface of the substrate BA at a substantially central portion in the X-axis direction and in the negative Y-axis direction. The arrangement position of the light source 131 is not limited to the above position, and may be arranged at a position other than the above. The light source 131 emits light to a part of the slit track ST (hereinafter also referred to as “irradiation region”) that passes through the facing position.

The light source 131 is not particularly limited as long as it is a light source that can emit light to the irradiation region. For example, an LED (Light Emitting Diode) can be used. In the present embodiment, the light source 131 is formed as a point light source in which an optical lens or the like is not particularly disposed, and emits diffused light from the light emitting unit 132. In the case of a point light source, it is not necessary to be an exact point, and light can be emitted from a finite surface as long as it can be considered that diffuse light is emitted from a substantially point-like position in terms of design and operation principle. Needless to say. By using the point light source in this way, the light source 131 emits diffused light to the irradiation area, although there is some influence of a change in the amount of light due to deviation from the optical axis and attenuation due to a difference in optical path length. It is possible to emit light substantially evenly. In addition, since the light is not condensed and diffused by the optical element, an error due to the optical element is hardly generated, and the straightness of the outgoing light to the slit track ST can be improved.

(2-2-2. Light receiver)
The light receiving unit 140 is provided at a position different from the light source 131 on the lower surface of the substrate BA. In this example, the light receiving unit 140 is disposed at a position in the positive direction of the Y axis on the lower surface of the substrate BA. The arrangement position of the light receiving unit 140 is not limited to the above position, and may be arranged at a position other than the above. The light receiving unit 140 includes a substrate 141 provided on the lower surface of the substrate BA and a light receiving array PA. The substrate 141 is a chip substrate on which the light receiving array PA is formed. In the present embodiment, the substrate 141 is provided separately from the substrate BA, but may be provided integrally with the substrate BA. The light receiving array PA is provided on the surface of the lower side of the substrate 141 (side facing a part of the slit track ST), and has a plurality of light receiving elements 142 along a direction corresponding to the disk radial direction R. The light receiving array PA is configured by arranging a plurality of light receiving elements 142 in an array at a predetermined pitch along a direction corresponding to the disk circumferential direction C.

Each light receiving element 142 emits light from the light source 131 and passes through the opposing position, and is subjected to the action of the reflecting slit 111 of the slit track ST, that is, light reflected by the reflecting slit 111 (hereinafter also referred to as “reflected light”). .) Is received by the light receiving surface 142a. Each light receiving element 142 converts each light signal into an electrical signal corresponding to the amount of light received.

The light receiving element 142 is not particularly limited as long as it can receive reflected light by the light receiving surface 142a and convert it into an electrical signal corresponding to the amount of light received, but for example, a photodiode can be used.

As described above, the encoder 100 is configured as a so-called “reflective” encoder that receives light emitted from the light source 131 and reflected by the reflection slit 111 by the light receiving element 142. The light receiving array PA, together with the slit track ST, constitutes a so-called two-grating optical system. In this embodiment, a case where a two-grating optical system is used will be described as an example. However, a two-grating optical system is not necessarily used, and a three-grating optical system may be used.

Further, the direction corresponding to the disk circumferential direction C on the substrate 141 is a shape in which the disk circumferential direction C on the disk 110 is projected onto the light receiving array PA. Similarly, the direction corresponding to the disk radial direction R in the substrate 141 is a shape in which the disk radial direction R in the disk 110 is projected onto the light receiving array PA. That is, the light emitted from the light source 131 is diffused light, and the light receiving array PA receives the reflected light. Therefore, the image projected on the light receiving array PA is enlarged by a predetermined enlargement factor ε (ε = (d1 + d2) / d1) according to the optical path length. That is, an image enlarged by ε times is projected onto the light receiving array PA. In addition, d1 is the optical path distance of the light from the light emission part 132 of the light source 131 to the slit track ST (reflection slit 111). d2 is an optical path distance of light from the slit track ST (reflection slit 111) to the light receiving array PA (light receiving element 142).

In the present embodiment, four light receiving elements 142 are arranged in one pitch of the reflective slits 111 arranged so as to have an incremental pattern (one pitch in the image projected on the light receiving array PA, which is the same as the pitch P). It has been. A plurality of sets each including four light receiving elements 142 are arranged at a predetermined pitch εP along a direction corresponding to the disk circumferential direction C. Each light receiving element 142 generates a periodic signal of one period at one pitch (also referred to as “electrical angle of 360 °”) by the rotation of the disk 110. Accordingly, when four light receiving elements 142 are included in one set corresponding to one pitch, adjacent light receiving elements 142 in one set generate electrical signals having a phase difference of 90 ° from each other. It will be. These electric signals are also referred to as “incremental signals” or their abbreviated “incremental signals”. Further, these electric signals are referred to as “A phase signal” (also referred to as “A + signal”), “B phase signal” (signal having a phase difference of 90 ° with respect to the A + signal, also referred to as “B + signal”), “ “A-bar phase signal” (a signal having a phase difference of 180 ° with respect to the A + signal. Also referred to as “A− signal”), “B-bar phase signal” (a signal having a phase difference of 180 ° with respect to the B + signal. “B− signal”). Also called.)

In the above description, the case where four light receiving elements 142 are included in one set corresponding to one pitch of the plurality of reflecting slits 111 arranged so as to have an incremental pattern has been described. However, the number of light receiving elements 142 in one set is not particularly limited.

(2-2-3. Translucent member)
The translucent member 160 is fixed to the light receiving surfaces 142 a of the plurality of light receiving elements 142 that form the light receiving array PA provided on the lower surface of the substrate 141. Thereby, the light receiving surface 142a of each light receiving element 142 is covered with the light transmitting member 160, respectively. The translucent member 160 is made of a material that has translucency with respect to light emitted from the light source 131 (for example, glass or transparent resin).

A slit array SA is formed on the surface of the lower side of the translucent member 160 (the side facing a part of the slit track ST). That is, the slit array SA is disposed between the slit track ST and the light receiving array PA. The slit array SA has a plurality of transmission slits 166 (an example of a second slit) along a direction corresponding to the disk radial direction R. The slit track SA has a light shielding portion 162 in a region other than the transmission slit 166 on the lower surface of the translucent member 160 so that the plurality of transmission slits 166 are arranged in an array along the direction corresponding to the disk circumferential direction C. Is provided.

Each transmission slit 166 transmits the reflected light. Each light shielding unit 162 shields (blocks) light. Each of the light shielding portions 162 can be formed by applying a light shielding material (such as chromium oxide) to the lower surface of the light transmitting member 160 configured to transmit light. In addition, you may form each light-shielding part 162 by methods other than application | coating, such as sticking the shielding member formed in plate shape on the lower surface of the translucent member 160. FIG.

Note that the material and manufacturing method of the translucent member 160 are not particularly limited.

Here, when each light receiving element 142 receives scattered light or stray light incident from an angle different from the reflected light that should be received, noise is generated. Such noise becomes a factor that reduces the position detection accuracy of the encoder 100. Further, in the present embodiment in which the light source 131 is formed as a point light source that emits diffused light, the reflected light is not incident on the light receiving surface 142 of each light receiving element 142 from the vertical direction as in the case of parallel light, but obliquely. It will enter from the direction of.

Here, when each transmission slit 166 is arranged corresponding to a direction perpendicular to the light receiving surface 142a of each light receiving element 142 (in the disc circumferential direction C between each transmission slit 166 and the light receiving surface 142a of each light receiving element 142). Let us consider the case where the positions in the corresponding directions are matched. In this case, part of the reflected light transmitted through the transmission slit 166 may be received by the light receiving element 142 that is different from the light receiving element 142 that should be received. Further, even if part of the reflected light that has passed through the transmission slit 166 is received by the light receiving element 142 that should be received by the light, the light penetrates through the substrate 141, and an area E (described later) related to the adjacent light receiving element 142. 6), carrier CA (see FIG. 6 described later) may occur. The region E is a region where the generated carrier CA can reach the corresponding light receiving element 142. In this case, when the carrier CA generated in the region E related to the adjacent light receiving element 142 moves to the light receiving element 142, so-called “crosstalk” in which an electric signal is generated in the light receiving element 142 occurs. Such crosstalk causes noise.

In this embodiment, as described above, the slit array SA having the plurality of transmission slits 166 that respectively transmit the reflected light is disposed between the slit track ST and the light receiving array PA. Then, as shown in FIG. 6, each transmission slit 166 is incident on the light receiving surface 142a of the light receiving element 142 corresponding to the reflected light (hereinafter also referred to as “reflected light L1”) that each light receiving element 142 should originally receive. As described above, the light receiving element 142 is disposed at a position corresponding to the traveling direction of the reflected light L1. At the same time, the slit array SA is formed by providing a light shielding portion 162 in a region other than the transmission slit 166 on the lower surface of the translucent member 160. Specifically, each light shielding portion 162 does not block the reflected light L1, but can block scattered light and stray light incident from an angle different from the reflected light L1. And the distance between the adjacent light shielding portion 162 and the adjacent light shielding portion 162 are adjusted. As a result, each transmission slit 166 causes the disc circle from a direction perpendicular to the light receiving surface 142a according to the traveling direction of the reflected light L1 so that the reflected light L1 is incident on the light receiving surface 142a of the corresponding light receiving element 142. They are arranged at positions offset in a direction corresponding to the circumferential direction C. The arrangement position of each transmission slit 166 is not limited to the above position, and the reflected light is reflected on the light receiving element 142 so that the reflected light L1 is incident on the light receiving surface 142a of the corresponding light receiving element 142. Any position corresponding to the traveling direction of L1 may be used. Furthermore, the arrangement position of each transmission slit 166 is a position corresponding to the traveling direction of the reflected light L1 with respect to the light receiving element 142 so that the reflected light L1 is incident on the light receiving surface 142a of the corresponding light receiving element 142. The position is not limited to this, and any position may be used as long as it is arranged in a direction corresponding to the circumferential direction C of the disk so as to transmit the reflected light L1.

By forming the translucent member 160 in this manner, the reflected light L1 can be transmitted through the transmission slit 166 and incident on the light receiving surface 142a of the corresponding light receiving element 142. Even if a part of the reflected light L1 received by the light receiving surface 142 of the corresponding light receiving element 142 penetrates the substrate 141, the carrier CA is generated in the region E (or the vicinity thereof) related to the light receiving element 142. It is possible. As a result, the carrier CA is moved to the light receiving element 142, so that the light receiving element 142 can generate an electrical signal. In addition, if there is no light blocking portion 162, scattered light and stray light incident on the light receiving surface 142a of the light receiving element 142 from other different angles are blocked by the light blocking portion 162 and not incident on the light receiving surface 142a of the light receiving element 142. It is possible. At the same time, if there is no light blocking portion 162, the light L2 that can cause the crosstalk can be blocked by the light blocking portion 162 and not incident on the light receiving surface 142a of the light receiving element 142. In FIG. 6, for convenience of explanation, the behavior in the case where the blocking part 162 is not provided is indicated by an imaginary line. Further, a part of the light that is reflected by the reflected light L1 and incident on the light receiving surface 142a of the corresponding light receiving element 142 and reflected by the light receiving surface 142a may be incident on the light receiving surface 142a again by internal reflection of the translucent member 160. Is possible.

(2-3. Position data generator)
As illustrated in FIG. 2, the position data generation unit 190 detects four incremental signals (A + signal, A + signal, phase shift from the plurality of light receiving elements 142 of the optical module 130 by 90 ° at the timing of detecting the position of the rotor m2. B + signal, A− signal, and B− signal). Then, based on the acquired incremental signal, the position data generation unit 190 calculates the position of the rotor m2 represented by the incremental signal, and outputs position data representing the position to the control device CT. Note that the position data generation method by the position data generation unit 190 is not limited to the case where the position data is generated by calculating the position of the rotor m2 from the incremental signal, and various methods can be used.

<3. Examples of effects, etc. according to this embodiment>
The servo system S according to this embodiment has been described above. In the present embodiment, a slit array SA is disposed between the slit track ST and the light receiving array PA. The slit array SA includes a plurality of transmission slits 166 that are arranged along a direction corresponding to the disk circumferential direction C and each transmit reflected light. Each of the transmission slits 166 allows the reflected light L1 to pass therethrough and blocks scattered light and stray light incident from other different angles. As a result, noise can be reduced and detection accuracy can be improved.

Further, in the present embodiment, in particular, each transmission slit 166 is arranged at a position corresponding to the traveling direction of the reflected light L1 with respect to the corresponding light receiving element 142. Thereby, since the reflected light L1 is incident on the light receiving surface 142a of the light receiving element 142 that should be received, detection accuracy can be improved even when the light source 131 is formed as a point light source that emits diffused light.

In this embodiment, in particular, the light transmitting member 160 is fixed to the light receiving surfaces 142a of the plurality of light receiving elements 142 forming the light receiving array PA. The slit array SA is formed by providing the light shielding portion 162 in a region other than the transmission slit 166 on the lower surface of the light transmitting member 160. With such a configuration, part of the light reflected by the light receiving surface 142 a of the light receiving element 142 can be incident again on the light receiving surface 142 a by internal reflection of the light transmitting member 160. Thereby, the amount of received light can be increased.

In addition, the effect by this embodiment demonstrated above is an example to the last, and it cannot be overemphasized that there exists a further effect.

<4. Modified example>
The embodiment has been described in detail with reference to the drawings. However, it goes without saying that the scope of the technical idea is not limited to the embodiment described here. It is obvious that a person having ordinary knowledge in the technical field to which the embodiment belongs can make various changes, corrections, combinations, and the like within the scope of the technical idea described in the claims. It is. Therefore, the subsequent techniques such as changes, corrections, combinations, and the like naturally belong to the scope of the technical idea. Hereinafter, such modifications will be described in order. In the following modifications and the like, portions different from the above embodiment will be mainly described. In addition, components having substantially the same functions as those of the above-described embodiment are represented by the same reference numerals in principle, and repeated description of these components will be omitted as appropriate.

(4-1. When a deflecting member is provided on a translucent member (1))
In the servo system S according to the present modification, differences from the above embodiment will be described.

As shown in FIG. 7, in this modification, a light transmissive member 160A is provided instead of the light transmissive member 160 described above. Hereinafter, differences of the translucent member 160A from the above-described translucent member 160 will be described. That is, in the light transmissive member 160A according to the present modification, each light shielding portion 162 is arranged such that each transmissive slit 166 corresponds to a direction perpendicular to the light receiving surface 142a of each light receiving element 142 (each transmissive slit 166 and The positions in the direction corresponding to the disk circumferential direction C with the light receiving surface 142a of each light receiving element 142 are substantially the same). Thus, each transmission slit 166 is disposed at a position corresponding to a direction perpendicular to the light receiving surface 142a of each light receiving element 142.

Further, a deflecting member 170 is provided at each of the transmitting slits 166 located below the light receiving surface 142a of each light receiving element 142 in the light transmitting member 160A. Each deflection member 170 is formed by appropriately processing a portion of each transmission slit 166 in the translucent member 160A or a material (for example, glass or transparent resin) having translucency with respect to light emitted from the light source 131. It is comprised by the member (for example, a lens, a prism, etc.) formed by processing using.

Each of these deflecting members 170 deflects the reflected light L1 transmitted through the corresponding transmission slit 166, respectively. Specifically, each deflecting member 170 causes the reflected light L1 transmitted through the corresponding transmission slit 166 to be perpendicular to the straight line CL along the traveling direction of the reflected light L1 and the light receiving surface 142a of the corresponding light receiving element 142. Each is deflected in a direction in which the angle θ with the straight line SL decreases. In this example, each deflection member 170 deflects the reflected light L1 transmitted through the corresponding transmission slit 166 in a direction in which the angle θ is approximately 0 °. That is, each deflecting member 170 is configured so that the reflected light L1 transmitted through the corresponding transmission slit 166 is incident on the light receiving surface 142a in a direction substantially perpendicular to the light receiving surface 142a of the corresponding light receiving element 142. To deflect. Each deflection member 170 is not limited to deflecting the reflected light L1 transmitted through the corresponding transmission slit 166 in a direction in which the angle θ is approximately 0 °, but in a direction in which the angle θ is decreased. Anything to do. Furthermore, each deflecting member 170 is not limited to the one that deflects the reflected light L1 transmitted through the corresponding transmission slit 166 in the direction in which the angle θ decreases, but may simply deflect it.

In this modification, each deflecting member 170 is provided on the translucent member 160A. Therefore, the position corresponding to the direction perpendicular to the light receiving surface 142a of each light receiving element 142 at which each transmission slit 166 is arranged is such that the reflected light L1 is incident on the light receiving surface 142a of the corresponding light receiving element 142. It can be said that the position corresponds to the traveling direction of the reflected light L1 with respect to the light receiving element 142.

By forming the translucent member 160A in this way, the reflected light L1 is deflected as described above by the deflecting member 170 when passing through the transmissive slit 166. As a result, the reflected light L1 transmitted through the corresponding transmission slit 166 can be incident on the light receiving surface 142a in a direction perpendicular to the light receiving surface 142a of the corresponding light receiving element 142. Even if a part of the reflected light L1 received by the light receiving surface 142 of the corresponding light receiving element 142 penetrates the substrate 141, the carrier CA is generated in the region E (or the vicinity thereof) related to the light receiving element 142. It is possible. In addition, if there is no light blocking portion 162, scattered light and stray light incident on the light receiving surface 142a of the light receiving element 142 from other different angles are blocked by the light blocking portion 162 and not incident on the light receiving surface 142a of the light receiving element 142. It is possible. At the same time, if there is no light blocking portion 162, it is possible to block the light that can cause the above-described crosstalk by the light blocking portion 162 so that it does not enter the light receiving surface 142a of the light receiving element 142. Further, if there is no deflection member 170, the light L3 that can cause the above-described crosstalk is deflected by the deflection member 170 as described above. Accordingly, the light L3 can be incident on the light receiving surface 142a of the corresponding light receiving element 142 in a direction perpendicular to the light receiving surface 142a of the corresponding light receiving element 142. In FIG. 7, for convenience of explanation, the behavior in the case where the deflection member 170 is not provided is indicated by an imaginary line. Further, a part of the light incident on the light receiving surface 142a of the corresponding light receiving element 142 and reflected by the light receiving surface 142a is reflected again on the light receiving surface 142a by the internal reflection of the light transmitting member 160A or the deflecting member 170. It is possible to make it incident.

Since the configuration other than the above can be configured in the same manner as the above embodiment, the description thereof is omitted.

The servo system S according to this modification has been described above. In this modification, the same effect as that of the above embodiment can be obtained. In this modification, the translucent member 160 </ b> A includes a deflecting member 170 configured to deflect the reflected light L <b> 1 transmitted through the corresponding transmitting slit 166. In particular, in this modification, the deflecting member 170 is configured to deflect the reflected light L1 transmitted through the corresponding transmission slit 166 in a direction in which the angle θ decreases. As a result, when the reflected light L1 passes through each transmission slit 166, it can be deflected in the direction in which the angle θ decreases by the deflecting member 170 and incident on the corresponding light receiving surface 142a of the light receiving element 142. Can be reduced. Moreover, since the pitch of the light receiving elements 142 can be reduced by reducing the crosstalk, the encoder 100 can have high resolution.

(4-2. When a deflecting member is provided on a translucent member (part 2))
The servo system S according to this modification will be described with respect to differences from the modification (4-1).

As shown in FIG. 8, in this modification, a deflection member 170A is provided in place of the deflection member 170 described above. Hereinafter, differences of the deflection member 170A from the deflection member 170 will be described. That is, each deflection member 170A according to the present modification condenses the reflected light L1 transmitted through the corresponding transmission slit 166 in the substantially central direction of the light receiving surface 142a of the corresponding light receiving element 142. That is, each deflecting member 170A enters the reflected light L1 transmitted through the corresponding transmission slit 166 into the light receiving surface 142a in a direction toward the substantially central side of the light receiving surface 142a of the corresponding light receiving element 142. , Each is condensed. Each deflecting member 170A is not limited to condensing the reflected light L1 transmitted through the corresponding transmission slit 166 in a substantially central direction of the light receiving surface 142a of the corresponding light receiving element 142, but simply deflects. It may be a thing.

By forming the translucent member 160A in this way, the reflected light L1 is deflected as described above by the deflecting member 170A when passing through the transmissive slit 166. As a result, the reflected light L1 transmitted through the corresponding transmission slit 166 can be incident on the light receiving surface 142a in a direction toward the substantially central side of the light receiving surface 142a of the corresponding light receiving element 142. Even if a part of the reflected light L1 received by the light receiving surface 142 of the corresponding light receiving element 142 penetrates the substrate 141, the carrier CA is generated in the region E (or the vicinity thereof) related to the light receiving element 142. It is possible. In addition, if there is no light blocking portion 162, scattered light and stray light incident on the light receiving surface 142a of the light receiving element 142 from other different angles are blocked by the light blocking portion 162 and not incident on the light receiving surface 142a of the light receiving element 142. It is possible. At the same time, if there is no light blocking portion 162, it is possible to block the light that can cause the above-described crosstalk by the light blocking portion 162 so that it does not enter the light receiving surface 142a of the light receiving element 142. Further, if the deflecting member 170A is not provided, the light L4 that can cause the above-described crosstalk is deflected by the deflecting member 170 as described above. Accordingly, the light L4 can be incident on the light receiving surface 142a of the corresponding light receiving element 142 in the direction toward the substantially central side of the light receiving surface 142a of the corresponding light receiving element 142. In FIG. 8, for convenience of explanation, the behavior in the case where there is no deflection member 170 </ b> A is shown by imaginary lines. In addition, a part of the light incident on the light receiving surface 142a of the corresponding light receiving element 142 and reflected by the reflected light L1 is again reflected on the light receiving surface 142a by the internal reflection of the light transmitting member 160A or the deflecting member 170A. It is possible to make it incident.

Since the configuration other than the above can be configured in the same manner as the modified example of (4-1) above, description thereof will be omitted.

The servo system S according to this modification has been described above. In the present modification, the same effect as in the modification (4-1) can be obtained. Further, in this modification, the deflecting member 170A is configured to collect the reflected light L1 transmitted through the corresponding transmission slit 166 in a substantially central direction of the light receiving surface 142a of the corresponding light receiving element 142. As a result, when the reflected light L1 passes through each transmission slit 166, the deflecting member 170A can concentrate the light in the substantially central direction of the light receiving surface 142a of the corresponding light receiving element 142 and enter the light receiving surface 142a. Crosstalk can be reliably reduced. As a result, even when there is vibration, it is possible to prevent the reflected light L1 transmitted through the corresponding transmission slit 166 from reaching the light receiving surface 142a of the corresponding light receiving element 142, so that the amount of received light is ensured. be able to.

(4-3. When a bubble wall is formed around the deflection member)
In the servo system S according to the present modification, differences from the modification (4-2) will be described.

As shown in FIG. 9, in this modification, a light transmissive member 160B is provided instead of the light transmissive member 160A described above. Hereinafter, the difference of the translucent member 160B from the above-described translucent member 160A will be described. That is, the translucent member 160B according to the present modification includes a bubble wall 180 as an example of a scattering portion formed so as to surround each deflection member 170A (excluding the incident surface of the reflected light L1). The bubble wall 180 can scatter the reflected light L1 propagating through the deflection member 170A into the deflection member 170A. The scattering portion is not limited to the bubble wall 180 as long as it is a portion that can scatter the reflected light L1 propagating through the deflection member 170A into the deflection member 170A. A crack, a muddy part, etc. may be sufficient. However, for convenience of explanation, a case where the scattering portion is the bubble wall 180 will be described below. The plurality of bubbles constituting the bubble wall 180 can be formed by processing the peripheral portion of each deflecting member 170A in the translucent member 160B using an appropriate processing method (for example, three-dimensional processing by laser irradiation). It is. Note that the deflection member 170 described above may be provided instead of the deflection member 170A.

In this modification, a transmissive member 160B in which a bubble wall 180 is formed so as to surround the periphery of the deflecting member 170A is formed. Accordingly, when the reflected light L1 is transmitted through the transmission slit 166 and condensed by the deflecting member 170A as described above and transmitted through the corresponding transmission slit 166, the reflected light L1 is deflected by the bubble wall 180. Scattering to the outside of the deflecting member 170A due to refraction or diffusion by the member 170A can be prevented. As shown in FIG. 9, at least part of the reflected light L1 incident on the deflecting member 170A is incident obliquely at a predetermined angle with respect to the normal line of the light receiving surface 142a. In such a case, it is difficult for the deflecting member 170A to cause all light to enter the corresponding light receiving element 142. However, according to the present modification, it is possible to prevent the bubble wall 180 from propagating through the deflecting member 170A and transmitting the reflected light L1 to the adjacent light receiving elements 142. Therefore, the influence of crosstalk can be further prevented. Furthermore, a part of the light reflected by the bubble wall 180 can be incident on the light receiving surface 142a of the corresponding light receiving element 142 by internal reflection of the deflecting member 170A.

Since the configuration other than the above can be configured in the same manner as the modified example of (4-2) above, description thereof will be omitted.

The servo system S according to this modification has been described above. In the present modification, the same effect as in the modification (4-2) can be obtained. In this modification, the translucent member 160B has a bubble wall 180 formed so as to surround the deflection member 170A. The bubble wall 180 can prevent the reflected light L1 from being scattered outside the deflecting member 170A due to refraction or diffusion when the reflected light L1 transmitted through the corresponding transmitting slit 166 is collected by the deflecting member 170A. . As a result, the reflected light L1 can be collected more and made incident on the corresponding light receiving element 142, so that the effect of reducing crosstalk can be further enhanced.

(4-4. Others)
In the above, the slit track ST having the plurality of reflective slits 111 arranged so as to have the incremental pattern is formed on the disk 110, but the embodiment of the present disclosure is not limited to this example. For example, a slit track having a plurality of reflective slits arranged so as to have a serial absolute pattern may be formed on the disk 110 instead of or in addition to the slit track ST. In this case, the absolute position of the rotor m2 is provided by providing a light receiving array in which a plurality of light receiving elements for receiving the light emitted from the light source 131 and reflected by the reflection slit are arranged on the substrate BA side of the optical module 130. It is possible to detect (absolute angle). In this case, a slit array having a plurality of transmission slits that transmit the light reflected by the reflection slit may be provided between the slit track corresponding to the serial absolute pattern and the light receiving array. Further, the slit track may be, for example, an absolute pattern other than the serial absolute pattern, a PWM modulated pattern, a reflective slit corresponding to a pattern representing the origin position, or the like.

In the above description, the case where the encoder 100, which is a reflective encoder in which both the light source 131 and the light receiving array PA are arranged on the substrate BA side of the optical module 130, has been described as an example. It is not limited to examples. For example, a so-called “transmission type” encoder in which a light source 131 and a light receiving array are disposed to face each other with a disk interposed therebetween may be used. In this case, a slit track having a plurality of transmission slits (an example of a first slit) that transmits light emitted from the light source 131 may be formed on the disk. As a result, each light receiving element forming the light receiving array can receive the light emitted from the light source 131 and transmitted through the transmission slit of the slit track passing through the facing position. In this case, a slit array having a plurality of transmission slits (an example of second slits) that respectively transmit the light transmitted through the transmission slits may be provided between the slit track and the light receiving array.

In the above description, the servo system includes the motor M that is a rotary motor, the encoder 100 that detects the position of the rotor m2 of the motor M, and the controller CT that controls the motor M based on the position data from the encoder 100. The case of applying to S has been described as an example. However, the embodiment of the present disclosure is not limited to this example. For example, a linear motor that moves the mover relative to the stator, an encoder that detects at least one of the position and speed of the mover of the linear motor, and a control that controls the linear motor based on the detection result of the encoder You may apply to a servo system provided with an apparatus.

In addition to those already described above, the methods according to the above-described embodiment and each modification may be used in appropriate combination.

In addition, although not illustrated one by one, the above-described embodiment and each modification are implemented with various modifications within a range not departing from the gist thereof.

100 Encoder 111 Reflective slit (example of first slit)
DESCRIPTION OF SYMBOLS 130 Optical module 131 Light source 142 Light receiving element 142a Light receiving surface 160 Translucent member 160A Translucent member 160B Translucent member 162 Light-shielding part 166 Transmission slit (an example of 2nd slit)
170 Deflection member 170A Deflection member 180 Bubble wall (an example of a scattering part)
C Rotation direction (example of measurement direction)
CT controller M motor (an example of a rotary motor)
m1 Stator m2 Rotor PA Light receiving array S Servo system SA Slit array SM Servo motor (Example of motor with encoder)
ST slit track

Claims

A slit track having a plurality of first slits arranged along the measurement direction;
An optical module capable of moving relative to the slit track in the measurement direction while facing a part of the slit track,
The optical module is
A light source configured to emit light to opposing portions of the slit track;
A light receiving array having a plurality of light receiving elements which are arranged along the measurement direction and each receive light subjected to the action of the first slit;
A slit array that is disposed between the slit track and the light receiving array and has a plurality of second slits that are arranged along the measurement direction and each transmit light that has been subjected to the action of the first slit. Encoder.
The light source is
A point light source that emits diffused light,
The second slit is
2. The encoder according to claim 1, wherein the encoder is disposed at a position corresponding to a traveling direction of the light with respect to the light receiving element so that the light subjected to the action of the first slit is incident on the corresponding light receiving element. .
The slit array
The encoder according to claim 1 or 2, wherein the encoder is formed by providing a light-shielding portion in a region other than the second slit on the surface on the slit track side of the translucent member fixed to the light-receiving surface of the light-receiving array.
The translucent member is
The encoder according to claim 3, further comprising a deflecting member configured to deflect light transmitted through each of the second slits.
The translucent member is
The encoder according to claim 4, further comprising a scattering portion formed so as to surround the periphery of the deflection member.
The deflection member is
The light transmitted through each of the second slits is deflected in a direction in which an angle between a straight line along the traveling direction of the light and a straight line perpendicular to the light receiving surface of the corresponding light receiving element decreases. The encoder according to claim 4 or 5, wherein the encoder is configured.
The deflection member is
6. The encoder according to claim 4, wherein light transmitted through each of the second slits is collected in a substantially central direction of the light receiving surface of the corresponding light receiving element.
A linear motor in which the mover moves relative to the stator, or a rotary motor in which the rotor rotates relative to the stator;
An encoder-equipped motor comprising: the encoder according to any one of claims 1 to 7 that detects at least one of a position and a speed of the mover or the rotor.
A linear motor in which the mover moves relative to the stator, or a rotary motor in which the rotor rotates relative to the stator;
The encoder according to any one of claims 1 to 7, which detects at least one of a position and a speed of the mover or the rotor;
And a control device configured to control the linear motor or the rotary motor based on a detection result of the encoder.