JP2005017023A - Optical encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To precisely and easily manufacture an optical encoder, which can detect the position of a reflector plate reliably without causing an electric signal outputted from an optical reader to vary greatly, even if the reflector plate flutters and the distance between the reflector plate and the optical reader varies some extent. <P>SOLUTION: The optical reader 2 is made to have a constitution in which it is separated into first and second blocks 3, 4; a light transmitting LED (light emitting diode) 310 whose positioning adjustment may be relatively rough and an amount-of-light-transmission monitor PD 320 are put together in the first block 3; an objective lens 410 requiring precise positioning, a half mirror 420, a light-shielding plate 430, and a photo IC 440 are put together in the second block 4; further, the objective lens 410 requiring positioning adjustment and the half mirror 420 are adjusted, by using open space in the second block 4. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical encoder which is attached to a driving body such as a motor and optically reads the driving amount and position of the driving body, and particularly relates to the structure of the optical reader.
[0002]
[Prior art]
The optical encoder is used to optically measure the driving amount and position of the motor. Regarding the configuration of a reflection-type optical encoder of a coaxial optical system, Japanese Patent Application Laid-Open No. 10-104021 (see FIG. 1 of Patent Document 1) describes a condensing optical encoder. In the optical encoder, the scale plate has a glass substrate, and the first and second reflective portions having the same width and different reflectivities are alternately formed on the surface thereof. For example, the first reflective portion includes: It is a total reflection film, and the second reflection part is a half mirror film. The amount of light received by the photodetector changes in a sine wave shape according to the position of the light spot formed by the emitted light, and encoding is performed based on this change in the amount of received light. Since a pulse signal is formed, a scale plate can be manufactured with high accuracy and easily compared to the case of forming a signal that changes in a sinusoidal shape using a two-layer reflector having a step in the optical axis direction. Since the encode pulse signal having a duty ratio of 50% can be obtained even if the relationship between the width of the reflecting portion and the diameter of the light spot changes, the encoder resolution can be easily changed.
[0003]
[Patent Document 1]
JP 10-104021 A
[0004]
[Problems to be solved by the invention]
However, Patent Document 1 describes a structure of a scale plate for easily and accurately manufacturing a scale plate in a reflection-type and coaxial optical encoder, but the scale plate and the scale plate are described. No consideration is given to reducing the influence of the relative distance fluctuation with the optical unit that detects the return light from the light source easily and at low cost. Patent Document 1 is an invention related to a concentrating reflection type optical encoder, and uses an astigmatism method to automatically correct a focus deviation of a light spot emitted from an optical unit and collected on a scale. An autofocus mechanism is provided. Therefore, in order to remove the influence of the relative distance fluctuation between the scale plate and the optical unit, there is a problem that an autofocus mechanism is required and the configuration of the optical encoder becomes complicated.
[0005]
The present invention has been made paying attention to the above-mentioned problems. Even if there is some variation in the relative distance between the scale plate, that is, the reflecting plate, and the optical unit, that is, the optical reader, the optical device can be configured with a simple structure and at low cost. An object of the present invention is to provide an optical encoder and a reflection-type optical reader of the optical encoder in which a signal from the reader can be stably obtained.
[0006]
Another object of the present invention is to make the optical encoder and the reflective optical reader of the optical encoder highly accurate and easy to assemble.
[0007]
[Means for Solving the Problems]
In order to solve the above-described problems, an optical encoder according to the present invention includes a reflecting plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, and irradiates light to the reflection plate. An optical encoder comprising a reflection type optical reader for detecting specularly reflected light from the optical reader, and corresponding electrical signals are output from the optical reader as the reflector and the optical reader move relative to each other. The optical reader includes a first block and a second block, the first block includes a light source that irradiates light to the reflecting plate, and the second block includes: A light projection / reception objective lens that irradiates the reflection plate with light from a light source as parallel rays so that the reflection plate includes a group of regular reflection portions and non-regular reflection portions, and collects the regular reflection light from the reflection plate. And the imaging position of the return light from the objective lens A light shielding plate having a slit pattern corresponding to a group of specular reflection portions and non-specular reflection portions, and light that directs forward light from the light source to the objective lens and directs return light returning from the objective lens to the light shielding plate A separator, a light receiving element that receives light that has passed through the slit pattern behind the light shielding plate, and a pin that is disposed at the focal position of the objective lens in front of the optical path of the return light separated via the light separator With a hall.
[0008]
The above configuration can be applied to various types of optical encoders regardless of whether they are a rotary type / linear type or an incremental type / absolute type. In the case of the rotary type, regular reflection portions and non-regular reflection portions are alternately formed in the reflection plate along the rotation direction, and the reflection plate and the optical reader perform relative movement in the rotation direction. In the case of the linear type, regular reflection portions and non-regular reflection portions are alternately formed on the reflection plate along the linear direction, and the reflection plate and the optical reader perform relative movement in the linear direction.
[0009]
Here, the “reflector plate in which regular reflection portions and non-regular reflection portions are alternately formed” refers to a regular reflection portion that regularly reflects light and a non-regular reflection that absorbs, transmits, or diffuses light, and does not regularly reflect light. Reflecting portions are reflecting plates formed alternately. For example, in the case of the rotary type, there is a metal rotating disk as a typical reflecting plate. In this case, the regular reflection part is formed on a mirror surface, and the non-regular reflection part is formed on a slit or rough surface that transmits light. The rough surface may be formed by, for example, laser half processing using laser light.
[0010]
In the case of the increment type, “the corresponding electrical signal is output from the optical reader” means that the electrical distance corresponding to the movement distance or the rotation angle from the optical reader is associated with the relative movement between the reflector and the optical reader. In the case of the absolute type, an electric signal corresponding to the absolute position or the absolute angle of the reflector with respect to the optical reader is output.
[0011]
The “objective lens” may be a single lens or a lens group including a plurality of lenses, or may have a lens holder that holds a side surface of the lens or the lens group, that is, an outer peripheral surface.
[0012]
The “pinhole arranged at the focal position of the objective lens” may be constituted by a member such as a pinhole plate, or may be constituted integrally with the second block.
[0013]
According to the present invention, the optical reader is configured to be separated into the first block and the second block, and the light source that may be relatively coarse in positioning adjustment is arranged in the first block, thereby achieving high-accuracy positioning. Since the required objective lens, light separator, light shielding plate, and light receiving element are integrated in the second block, a manufacturing process that does not require adjustment in the manufacturing process and a manufacturing process that requires high-precision positioning adjustment Therefore, it is possible to manufacture an efficient optical encoder.
[0014]
The optical encoder according to the present invention has a configuration of a “telecentric optical system” having a pinhole arranged at the focal position of the objective lens. As is well known, a telecentric optical system is an optical system in which only parallel light incident on a lens contributes to image formation. Therefore, even if the reflection plate flutters in the process of relative movement between the reflection plate and the optical reader and the distance between the reflection plate and the optical reader changes slightly, an image is formed on the light shielding plate and the light receiving element. The size of the image of the reflecting plate is maintained substantially constant, and the electrical signal output from the optical reader does not vary so much, and the position of the reflecting plate can be detected with high reliability.
[0015]
In the optical encoder according to the present invention, the light emitted from the light source is first collimated by the objective lens and then applied to the reflecting plate. Then, the light is specularly reflected by the specular reflection portion formed on the reflecting plate, and the specular reflected light Is collected by the objective lens, and the collected light is separated by the light separator, travels to the pinhole, passes through the pinhole and the light shielding plate, and is received by the light receiving element. Here, with the relative movement of the reflecting plate and the optical reader, the light receiving element receives only the light regularly reflected by the specular reflection portion among the regular reflection portion and the non-specular reflection portion alternately formed on the reflection plate. In order to receive light, for example, an incremental optical encoder outputs a continuous pulse signal after the specularly reflected light received by the light receiving element is electrically processed. In the case of the absolute type, there are multiple rows of patterns in which regular reflection portions and non-specular reflection portions are alternately formed on the reflection plate along the direction perpendicular to the movement direction of the reflection plate, and they indicate the absolute position of the reflection plate. The optical encoder outputs a multi-bit code that directly indicates an absolute position or an absolute angle.
[0016]
In the case of an absolute optical encoder, in order to read a pattern in which a plurality of regular reflection portions and non-regular reflection portions are alternately formed, a plurality of optical readers are associated with the plurality of rows of patterns. It is desirable to provide it.
[0017]
In one embodiment of the present invention, the second block is opened so that at least a part of the side surface of the objective lens is exposed, and the lens guide is slidably supported in the principal axis direction of the objective lens; And a light separator holding surface that holds the light separator with an inclination of about 45 degrees with respect to the principal axis direction of the objective lens, and the light separator holding surface is opened.
[0018]
In this embodiment, the objective lens preferably has a side surface, that is, an outer peripheral surface having a length with respect to the main axis direction, and the side surface can slide with respect to the lens guide. The objective lens is fixed to the lens guide by sliding the objective lens in the main axis direction while applying an adjustment jig to a part of the exposed side surface of the objective lens, and then adjusting the position with respect to the lens guide, and then fixing it by bonding. It is preferable to do this. Further, the light separator is preferably fixed to the light separator holding surface by adhesion or the like.
[0019]
According to this embodiment, at the time of manufacturing the second block, the objective lens and the optical separator that require positioning adjustment can be easily adjusted by using the open space in the second block. Manufacturing of an accurate optical encoder is facilitated.
[0020]
Furthermore, according to this embodiment, since the lens guide and the light separator holding surface in the second block become an open space, for example, the lens guide and the light separator holding surface in the second block are formed by resin molding. In this case, the mold to be used can be easily manufactured, and the lens guide and the light separator holding surface can be formed with high accuracy.
[0021]
In one embodiment of the present invention, the second block is formed by resin molding, and the pinhole is formed integrally with the second block by resin molding. According to this embodiment, since the pinhole is formed integrally with the second block by resin molding, a member such as a pinhole plate is not required, so that the pinhole can be formed at a low cost. The positional relationship with other components in the second block is improved, and a highly accurate optical encoder can be manufactured. In particular, in the positional relationship between the pinhole and the objective lens, since the pinhole is accurately arranged at the focal position of the objective lens, the effect of the telecentric optical system can be exhibited well.
[0022]
In one embodiment of the present invention, the second block holds the objective lens and the light separator, and further includes a third block having a pinhole, and a fourth block holding the light shielding plate and the light receiving element. It consists of blocks.
[0023]
In order to obtain an appropriate electrical signal from the light receiving element in the optical encoder, the positions of the light shielding plate and the light receiving element in the second block must be accurately adjusted with respect to the reflecting plate, the objective lens, and the pinhole. There is. Therefore, according to this embodiment, the second block in the optical reader is further divided into two blocks, a third block and a fourth block, and the light shielding plate and the light receiving element are made into the fourth block. Since it is configured to be mounted, the light shielding plate and the light receiving element can be easily positioned and adjusted with respect to the third block, and manufacturing of a highly accurate optical encoder is facilitated.
[0024]
In one embodiment of the present invention, the first block is joined to the holding surface side holding the optical separator to the third block with the third block as the center, and the pinhole of the third block is the center. The fourth block is formed on the opposite side of the holding surface for holding the light separator.
[0025]
Further, the optical encoder according to the present invention irradiates light to the reflection plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, and reflects regular reflection light from the reflection plate. An optical encoder comprising a reflection-type optical reader for detection, wherein a corresponding electrical signal is output from the optical reader as the reflector and the optical reader move relative to each other. The container irradiates the reflector with light, and irradiates the reflector with the light from the light source as parallel rays so that the reflector includes a group of regular reflection parts and non-regular reflection parts. And a light-shielding plate having a slit pattern corresponding to a group of regular reflection portions and non-regular reflection portions disposed at the imaging position of the return light returning from the objective lens, The objective lens for forward light from the light source The light separator that directs the return light that returns from the objective lens to the light shielding plate, the light receiving element that receives the light that has passed through the slit pattern behind the light shielding plate, and the light separator are separated. An optical reader mounting portion comprising a pinhole disposed at the focal position of the objective lens in front of the optical path of the return path light and a substantially flat plate portion formed so as to extend in a direction perpendicular to the principal axis direction of the objective lens. And an attachment portion whose attachment surface of the optical reader is perpendicular to the principal axis direction of the objective lens.
[0026]
Here, the “mounting surface of the optical reader on the flat plate portion” is a reference plane for mounting the optical reader with respect to the optical encoder when the optical reader is mounted on the optical encoder. According to the present invention, since the mounting surface of the optical reader is perpendicular to the principal axis direction of the objective lens, if the reflector is mounted parallel to the mounting surface of the optical reader, the direction of the light projecting axis in the optical reader is It becomes perpendicular to the reflecting plate, making it easy to manufacture a highly accurate optical encoder.
[0027]
Next, the reflection type optical reader according to the present invention irradiates light to a reflection plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, and reflects regular reflection light from the reflection plate. A reflective optical reader used in an optical encoder that optically reads and outputs a corresponding electrical signal with relative movement with respect to the reflector, the reflective optical reader comprising a first block And the second block, the first block is provided with a light source that irradiates light to the reflector, and the second block is a group of light from the light source as parallel rays on the reflector. Spot illumination so that the regular reflection part and the non-specular reflection part are included, and a projection / light reception objective lens that collects regular reflection light from the reflector, and an imaging position of the return light returning from the objective lens Corresponding to a group of regular reflection parts and non-specular reflection parts A light shielding plate having a lit pattern, a light separator for directing the forward light from the light source to the objective lens and the returning light returning from the objective lens to the light shielding plate, and light behind the light shielding plate that has passed through the slit pattern And a pinhole disposed at the focal position of the objective lens in front of the optical path of the return path light separated via the optical separator.
[0028]
Also in the reflection type optical reader according to the present invention, the above configuration can be applied to various types of optical encoders regardless of the rotary type / linear type or the incremental type / absolute type.
[0029]
Also in the reflection type optical reader according to the present invention, the optical reader is separated into the first block and the second block, and the light source which may be relatively coarsely positioned is arranged in the first block. Since the objective lens, the light separator, the light shielding plate, and the light receiving element that require highly accurate positioning are integrated in the second block, the manufacturing process that does not require adjustment in the manufacturing process and the high accuracy The manufacturing process that requires positioning adjustment can be separated, and an efficient reflective optical reader can be manufactured.
[0030]
Further, the reflection-type optical reader according to the present invention also has a “telecentric optical system” with a pinhole arranged at the focal position of the objective lens, so that the relative movement between the reflection plate and the optical reader can be reduced. Even if the reflection plate flutters in the process and the distance between the reflection plate and the optical reader varies slightly, the size of the image of the reflection plate formed on the light shielding plate and the light receiving element is maintained almost constant. Therefore, the electrical signal output from the optical reader does not vary so much, and the position of the reflector can be detected with high reliability.
[0031]
In one embodiment of the present invention, the second block holds the objective lens and the light separator, and further includes a third block having a pinhole, and a fourth block holding the light shielding plate and the light receiving element. It consists of blocks.
[0032]
Also in this embodiment, the second block in the optical reader is further divided into two blocks, a third block and a fourth block, and the light shielding plate and the light receiving element are mounted on the fourth block. Because of the configuration, the light shielding plate and the light receiving element can be easily positioned and adjusted with respect to the third block, and the manufacture of a highly accurate reflective optical reader is facilitated.
[0033]
In one embodiment of the present invention, the second block is provided with a mounting portion of the optical reader composed of a substantially flat plate portion formed so as to extend in a direction perpendicular to the principal axis direction of the objective lens. The mounting surface of the optical reader in the flat plate portion is perpendicular to the principal axis direction of the objective lens.
[0034]
Also in this embodiment, since the mounting surface of the optical reader is perpendicular to the principal axis direction of the objective lens, if the reflector is mounted in parallel with the mounting surface of the optical reader, the direction of the light projecting axis in the optical reader Becomes perpendicular to the reflecting plate, and it becomes easy to manufacture a high-precision optical encoder by using this reflective optical reader.
[0035]
Further, the reflection type optical reader according to the present invention irradiates light to a reflection plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, and optically reflects the regular reflection light from the reflection plate. Is a reflection type optical reader used in an optical encoder that outputs a corresponding electrical signal with relative movement with respect to a reflection plate, and a light source that irradiates light to the reflection plate, As a parallel light beam, the reflecting plate is irradiated with a spot so as to include a group of regular reflection portions and non-regular reflection portions, and a projection / reception objective lens that collects regular reflection light from the reflection plate, and an objective lens A light shielding plate having a slit pattern corresponding to a group of specular reflection portions and non-specular reflection portions arranged at the imaging position of the return light returning from the lens, and forward light from the light source toward the objective lens and returning from the objective lens Return light to the shading plate A light separator, a light receiving element that receives light that has passed through the slit pattern behind the light shielding plate, and an objective lens focal position in front of the optical path of the return light separated through the light separator. A mounting portion of the optical reader comprising a pinhole and a substantially flat plate portion formed so as to extend in a direction perpendicular to the principal axis direction of the objective lens, and the mounting surface of the optical reader on the flat plate portion is And a mounting portion that is perpendicular to the main axis direction.
[0036]
Also in this invention, since the mounting surface of the optical reader is perpendicular to the principal axis direction of the objective lens, if the reflector is mounted in parallel with the mounting surface of the optical reader, the direction of the light projecting axis in the optical reader is It becomes perpendicular to the reflecting plate, and it becomes easy to manufacture a highly accurate optical encoder by using this reflection type optical reader.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
1 and 2 show an incremental type and rotary optical encoder 1 according to a first embodiment of the present invention. 1A is a front view, FIG. 1B is a left side view, and FIG. 2 is an AA cross-sectional view of FIG.
[0038]
1A, 1B, and 2, an optical encoder 1 includes a shaft 101 coupled to a motor or the like, a bearing 102 of the shaft 101, a metal base 103 that holds the bearing 102, A reflection plate 104 fixed to the shaft 101; a flange 100 as an auxiliary material for fixing the reflection plate 104 to the shaft 101; a reflection-type optical reader 2 disposed opposite to the reflection plate 104; A metal plate 105 to which the reader 2 is fixed, a circuit board 106 for taking out and processing an electrical signal from the optical reader 2, a substrate support rod 107 for supporting the circuit board 106 on the plate 105, and a reflector 104 And the optical reader 2 and the circuit board 106 and are electrically connected to the circuit board 106 and a metal cylindrical case 108 fixed to the base 103. An electric cord 109 that is comprised of a bushing 110. an auxiliary material when fixing the electrical cord 109 to the casing 108.
[0039]
FIG. 3 is a perspective view of the optical encoder 1 with the case 108, the electric cord 109, and the bush 110 removed. In FIG. 3, the same components as those shown in FIGS. 1 and 2 are given the same reference numerals and a part of the description is omitted.
[0040]
The reflection plate 104 is a rotating disk formed of a metal having a thickness of 0.1 mm, and a regular reflection portion and a non-regular reflection portion are alternately formed along the rotation direction on the surface facing the optical reader 2. ing. The reflector 104 also rotates with the rotation of the shaft 101 connected to a motor or the like, and the specularly reflected light from the reflector 104 is optically read by the optical reader 2 and is electrically processed in the circuit board 106, and the electric cord 109 is used. An electrical signal is output.
[0041]
FIG. 4 is a diagram showing a configuration mainly related to the optical reader 2 and electrical processing in the optical encoder 1. In FIG. 4, the same elements as those shown in FIGS. 1 to 3 are given the same reference numerals and a part of the description is omitted. The main components forming the optical system of the optical reader 2 are a light emitting LED 310, a half mirror 420, an objective lens 410, a pinhole 401, a light shielding plate 430, and a photo IC 440. Each component will be described in detail later. The components related to the electrical processing are generated by the light projecting circuit 330 that drives the light projecting LED 310 that irradiates light to the reflector 104 and the photo IC 440 after the photo IC 440 receives the light reflected by the reflector 104. A light receiving circuit 450 that amplifies and shapes the electric signal, a signal processing unit 451 that generates a pulse signal from the electric signal obtained by the light receiving circuit 450, and an output that outputs the electric signal obtained from the signal processing unit 451 to the outside. Circuit 452.
[0042]
FIG. 5 is a front view of the reflecting plate 104. The reflection plate 104 is formed in a disk shape, and a reflection band 120 in which regular reflection portions and non-regular reflection portions are alternately formed is provided at the peripheral portion thereof, and the shaft 101 is fixed through the central portion. The shaft hole 121 is opened.
[0043]
FIG. 6 is an enlarged view of a portion E in FIG. In FIG. 5, the reflection band 120 is composed of three rows of reflection bands including a first reflection band 122, a second reflection band 123, and a third reflection band 124, and each a part is a non-regular reflection part. Thus, the part b becomes a regular reflection part. These reflection bands are formed using a laser processing machine. That is, a metal disk having a mirror surface is prepared, and the surface of the metal disk a portion is roughened by laser irradiation. As a result, the part a becomes a rough surface and becomes a non-specular reflection part that diffusely reflects light, and the part b becomes a specular reflection part while maintaining a mirror surface state. In the reflection plate 104, the regular reflection portions and the non-regular reflection portions are alternately formed, and the optical reader 2 receives only the reflected light from the regular reflection portion, whereby the pulse signal can be obtained. The second reflection band 123 contributes to A-phase and B-phase pulse signal generation in the incremental encoder, and the first reflection band 122 and the third reflection band 124 contribute to Z-phase pulse signal generation. .
[0044]
FIG. 7 is an external view of the optical reader 2 in the incremental type rotary optical encoder 1 according to the first embodiment of the present invention. FIG. 8 is a cross-sectional view of the optical reader 2, and is a view seen from the direction B in FIG. The optical reader 2 includes a first block 3 including a light projection LED 310, a light projection amount monitor PD 320, and a first block main body 390 for holding these optical components, a light projection / reception objective lens 410, a half mirror 420, and a light shielding plate. 430, a photo IC 440 as a light receiving element, and a second block 4 including a second block main body 490 that holds those optical components. FIG. 8 also shows a circuit board 106 attached to the optical reader 2.
[0045]
FIG. 9A is a diagram in which the first block 3 and the second block 4 are separated from each other in FIG. FIG. 9B is a diagram in which the first block 3 and the second block 4 are separated in FIG.
[0046]
The projection LED 310 is press-fitted and fixed in the projection LED insertion hole 311 of the first block main body 390 and projects toward the half mirror 420 and the objective lens 410.
[0047]
The light projection amount monitor PD 320 is press-fitted and fixed in the light projection amount monitor PD insertion hole 321 of the first block main body 390, and monitors the light projection amount projected from the light projection LED 310 and reflected by the half mirror 420. Note that the light projection amount monitor PD320 may be adopted as necessary in accordance with the use conditions of the optical encoder 1.
[0048]
The objective lens 410 is adhered and fixed to a lens guide of the second block main body 490, which will be described in detail later, and a group of regular reflection parts and non-regular reflection parts are formed on the reflection plate 104 by using the light from the projection LED 310 as parallel rays. Spot illumination is performed so as to include light, and regular reflection light from the reflector 104 is condensed. The objective lens 410 has a substantially cylindrical shape, and its side surface, that is, the outer peripheral surface has a length with respect to the main axis direction, is formed by resin molding, and a concave portion 412 is formed in the central portion of the cylindrical outer peripheral surface 411 over the circumference. It becomes.
[0049]
Returning to FIG. 6, the area of the spot irradiated with the spot on the reflector 104 is approximately the same size as the circle E. That is, the spot irradiation is performed so as to include the first reflection band 122, the second reflection band 123, and the third reflection band 124.
[0050]
The half mirror 420 is bonded and fixed to a half mirror bonding surface of the second block main body 490, which will be described in detail later, and transmits a part of the amount of forward light from the projection LED 310 to the objective lens 410, and from the objective lens 410. Reflects a part of the light amount of the returning light. That is, forward light from the projection LED 310 is directed to the objective lens 410, and return light returning from the objective lens 410 is directed to the light shielding plate 430.
[0051]
The light shielding plate 430 is a thin metal plate having a thickness of 0.05 mm, and a slit pattern corresponding to the regular reflection portion and the non-regular reflection portion in the reflection band 120 of the reflection plate 104 is formed at the center. FIG. 10 is a front view of the light shielding plate 430. The light shielding plate 430 is formed with a first slit row 434, a second slit row 435, a third slit row 436, and a fourth slit row 437, which are the slit patterns. As shown in FIG. Here, the first slit row 434 corresponds to the first reflection band 122, and the fourth slit row 437 corresponds to the third reflection band 124, both of which are related to the Z-phase output of the incremental encoder. The second slit row 435 corresponds to the A phase output corresponding to the second reflection band 123, and the third slit row 436 corresponds to the second reflection band 123, which relates to the B phase output. The light shielding plate 430 is fixed to the light shielding plate attachment portion 432 that is the imaging position of the return path light in the second block main body 490 by screwing the light shielding plate attachment hole 431.
[0052]
After the light shielding plate 430 is fixed to the second block main body 490, the photo IC 440 is press-fitted and fixed to the four photo IC insertion guides 441 of the second block main body 490, and passes through the slit pattern of the light shielding plate 430. Is received. The first block main body 390 and the second block main body 490 are formed by resin molding, and the four photo IC insertion guides 441 are integrally formed when the second block main body 490 is resin molded. A pinhole 401 is formed at the objective lens focal position of the return light reflected by the half mirror 420. The pinhole 401 is resin-molded integrally with the second block body 490.
[0053]
A mounting bracket 402 for the optical reader 2 is provided in the second block main body 490 so as to extend in two directions (opposite directions) perpendicular to the main axis direction of the objective lens 410. The bracket hole 403 of the mounting bracket 402 is fixed with a screw so that the direction of the light projecting axis of the optical reader 2 is perpendicular to the reflecting plate 104. The mounting bracket 402 is also resin-molded integrally with the second block main body 490. A bracket rib 404 is provided on one side surface of the mounting bracket 402. The bracket rib 404 reinforces the second block body 490 so that the mounting bracket 402 does not tilt and the second block 4 can maintain the direction perpendicular to the main axis direction of the objective lens 410 when the second block body 490 is formed by resin molding. And for reinforcing the direction of the light projecting axis of the optical reader 2 so that it can be maintained perpendicular to the reflector 104 after the optical reader 2 is attached to the optical encoder 1. The resin is molded integrally with the second block body 490 together with the mounting bracket 402.
[0054]
The first block main body 390 is provided with a first block combining protrusion 301, a first block combining surface 302, and the second block main body 490 is provided with a second block combining protrusion 405 and a second block combining surface 406. 3 and the second block 4 are combined to form the optical reader 2, the inner surface of the first block combining protrusion 301 is joined to the second block combining surface 406, and at the same time, the inner surface of the second block combining protrusion 405 is Joined to one block merged surface 302. After the first block 3 and the second block 4 are combined, an adhesive is applied in the vicinity of the joint portion between the combined projection and the combined surface, and the first block 3 and the second block 4 are combined and fixed. An optical reader 2 is formed.
[0055]
The first block uniting protrusion 301 and the first block uniting surface 302 are resin-molded integrally with the first block body 390. The second block uniting protrusion 405 and the second block uniting surface 406 are resin-molded integrally with the second block main body 490. The first block main body 390 is provided with a first block substrate guide 303, and the second block main body 490 is provided with a second block substrate guide 407, and the first block 3 and the second block 4 are fixedly joined together to form an optical reader. After forming the circuit board 2, the circuit board 106 is used as a guide when the circuit board 106 is attached to the optical reader 2. The first block substrate guide 303 is resin-molded integrally with the first block body 390, and the second block substrate guide 407 is resin-molded integrally with the second block body 490.
[0056]
Returning to FIG. 4, the action of the light beam in the optical reader 2 will be described. The light emitted from the projection LED 310 passes through the half mirror 420, is collimated by the objective lens 410, and is applied to the surface of the reflector 104 (light ray L11). The light reflected by the surface of the reflecting plate 104 is condensed by the objective lens 410 and then reflected by the half mirror 420 at a right angle, and then passes through the pinhole 401 and further passes through the slit pattern of the light shielding plate 430. Head to the photo IC 440 (light ray L12).
[0057]
FIG. 11 is an external view of a state in which the first block body 390 and the second block body 490 are separated from each other in the optical reader 2 in a state where optical components such as the objective lens 410 are not yet held. In FIG. 11, the optical component is held. 11 and 12, the same components as those shown in FIGS. 7 to 9 described above are given the same reference numerals and description thereof is partially omitted.
[0058]
In FIG. 11, the second block main body 490 is provided with a lens guide 414 having a V-groove-shaped V guide portion 413, which supports the objective lens 410 so as to be slidable in the main axis direction, as will be described in detail later. As can be seen from FIG. 12, when the objective lens 410 is supported, the lens guide 414 is opened so that the concave portion 412 of the objective lens 410 is exposed. This is for adjusting the position of the objective lens 410.
[0059]
The second block main body 490 is provided with a half mirror bonding surface 421 for bonding the half mirror 420. The half mirror adhesion surface 421 has a surface in contact with two outer peripheral edge portions of the left and right portions of the half mirror 420 and is formed with an inclination of 45 degrees with respect to the main axis direction of the objective lens 410. After the adhesive is applied to the half mirror bonding surface 421, the half mirror 420 is bonded and fixed at an angle of 45 degrees with respect to the principal axis direction of the objective lens 410 by pressing the half mirror 420 against the half mirror bonding surface 421. Is done.
[0060]
The projection LED insertion hole 311 is provided with a projection LED press-fitting projection 312. When the projection LED 310 is press-fitted and fixed in the projection LED insertion hole 311, the outer peripheral surface of the projection LED 310 is used for projection LED press-fitting. It is press-fitted while crushing the protrusion 312.
[0061]
Next, a method for manufacturing the optical reader 2 of the optical encoder 1 according to the first embodiment of the present invention will be described. First, manufacture of the first block 3 and manufacture of the second block 4 excluding the light shielding plate 430 and the photo IC 440 are performed, and then the first block 3 and the second block 4 are combined by the method described above, and finally The light shielding plate 430 and the photo IC 440 are attached to the second block 4. Since the manufacturing method of the 1st block 3 was described previously, the description is abbreviate | omitted.
[0062]
The manufacturing method of the second block 4 is as follows. First, the half mirror 420 is bonded and fixed to the half mirror bonding surface 421 with the mounting bracket 402 as a reference, and then the objective lens 410 is positioned and adjusted in the principal axis direction and then bonded to the V guide portion 413. Fix it.
[0063]
The adhesive fixing method of the half mirror 420 is such that first the back surface of the mounting bracket 402 is placed on a flat surface, then an adhesive is applied to the half mirror adhesive surface 421, and two outer peripheral edge portions on the left and right sides of the half mirror 420 Is pressed against the half mirror adhesive surface 421. At that time, a coaxial sensor that irradiates parallel light obliquely upward with an inclination of 45 degrees with respect to the flat surface on which the mounting bracket 402 is installed is used, and the half mirror 420 is irradiated to detect the reflected light. Thus, the tilt of the half mirror 420 may be corrected. According to such a manufacturing method, it is possible to eliminate the tilt error of the half mirror 420 caused by variations in the adhesive layer due to variations in the application of the adhesive.
[0064]
13 and 14 are explanatory diagrams of a method of positioning and adjusting the objective lens 410 to the V guide portion 413 to be bonded and fixed. 13 is a view of the second block 4 as viewed from the back surface of the mounting bracket 402, and FIG. 14 is a cross-sectional view of the second block 4 as viewed from the side of the objective lens 410. For the positioning adjustment of the objective lens 410, a slide adjusting jig 900, an adjusting slit plate 903, and a positioning adjusting CCD 904 are used as positioning adjusting jigs. The slide adjustment jig 900 slides the objective lens 410 in the main axis direction, and includes a lever 901 and a slide jig projection 902. The adjustment slit plate 903 is disposed at a position away from the back surface of the mounting bracket 402 by a distance L, and has a slit (not shown). The distance L is a distance formed by the mounting bracket 402 and the reflection plate 104 when the optical reader 2 is mounted on the plate 105 in the optical encoder 1. The positioning adjustment CCD 904 is disposed at a position where the photo IC 440 is held.
[0065]
To adjust the positioning of the objective lens 410, first, the objective lens 410 is mounted at an appropriate position on the V guide portion 413, and then the adjustment slit plate 903 is irradiated from the back surface with a light source (not shown) to adjust the slit of the adjustment slit plate 903. These images are formed on the positioning adjustment CCD 904 through the objective lens 410 and the half mirror 420. Here, the lever 901 is appropriately moved in the main axis direction of the objective lens 410 while the slide jig projection 902 of the slide adjustment jig 900 is engaged with the concave portion 412 of the objective lens 410 to press the objective lens 410 in the C direction. By sliding, the objective lens 410 can be slid in the main axis direction while being pressed against the V guide portion 413. That is, since the cylindrical outer peripheral surface 411 has a length with respect to the main axis direction of the objective lens 410, it can slide with respect to the V guide portion 413. At this time, the output of the positioning adjustment CCD 904 is monitored using a display (not shown), and after confirming that the slit image of the adjustment slit plate 903 is imaged most clearly on the positioning adjustment CCD 904, The objective lens 410 is adhered and fixed to the V guide portion 413 by applying an adhesive to the joint surface between the outer peripheral surface 411 and the V guide portion 413.
[0066]
With this manufacturing method, the half mirror 420 can be held at an angle of 45 degrees with respect to the mounting bracket 402, and the mounting bracket 402 is formed perpendicular to the V guide portion 413 that holds the objective lens 410. The angle formed by the main axis of the objective lens 410 and the half mirror 420 is 45 degrees, and the light incident on the objective lens 410 perpendicular to the mounting surface of the mounting bracket 402 is bent at 90 degrees by the half mirror 420, and the pin The hole 401, the light shielding plate 430, and the photo IC 440 can be led.
[0067]
Next, although the 1st block 3 and the 2nd block 4 are united, since the uniting method was described previously, the description is abbreviate | omitted. Next, a method for attaching the light shielding plate 430 and the photo IC 440 to the combined block will be described. In this case, an adjustment reflection plate 905 is used instead of the adjustment slit plate 903 shown in FIG. The reflection plate for adjustment 905 has a reflection band in which regular reflection portions and non-regular reflection portions having the same pitch as the reflection band formed on the reflection plate 104 are alternately formed. It is attached to a rotating mechanism (not shown) at a position away from the back surface of 402 by a distance L, and is rotated at a constant rotational speed.
[0068]
Here, the light blocking plate 430 is temporarily fixed to the combined light blocking plate mounting portion 432 of the block by temporarily fixing the light blocking plate mounting hole 431, and the photo IC 440 is press-fitted and fixed to the photo IC insertion guide 441. In addition, a light receiving circuit 450 is electrically connected to the photo IC 440, and an oscilloscope (not shown) is connected to the light receiving circuit 450. Next, the adjustment reflection plate 905 is rotated at 1500 rpm, the projection LED 310 is turned on to project light onto the rotating adjustment reflection plate 905, and the reflected light from the adjustment reflection plate 905 is received by the photo IC 440. To do. Here, using an oscilloscope, the position of the light shielding plate 430 with respect to the light shielding plate mounting portion 432 is adjusted while monitoring the electric signal from the amplified and waveform-shaped photo IC 440. After confirming that a uniform sine waveform is obtained from the photo IC 440, the light shielding plate 430 is fixed by screwing the light shielding plate attachment hole 431 to the light shielding plate attachment portion 432.
[0069]
According to this embodiment, the optical reader 2 is separated into the first block 3 and the second block 4, and the light projection LED 310 and the light projection amount monitor PD 320, which may have relatively coarse positioning adjustment, are arranged in the first block 3. The objective lens 410, the half mirror 420, the light shielding plate 430, and the photo IC 440 that require high-accuracy positioning are collected in the second block 4 by using a press-fitting method that does not require adjustment. Because it is fixed while performing high-precision positioning adjustment, it is possible to separate the manufacturing process that does not require adjustment in the manufacturing process from the manufacturing process that requires high-precision positioning adjustment, and an efficient optical type The encoder can be manufactured.
[0070]
According to this embodiment, since the configuration of a “telecentric optical system” in which the pinhole 401 is disposed at the focal position of the objective lens 410, the reflection plate is in the process of relative movement between the reflection plate 104 and the optical reader 2. Even if the 104 fluctuates and the distance between the reflection plate 104 and the optical reader 2 slightly varies, the size of the image of the reflection plate 104 formed on the light shielding plate 430 and the photo IC 440 is maintained almost constant. Thus, the electrical signal output from the optical reader 2 does not vary so much, and the position of the reflector 104 can be detected with high reliability.
[0071]
According to this embodiment, since the optical reader 2 is configured to be separated into the first block 3 and the second block 4, the objective lens 410 and the half mirror 420 that require positioning adjustment are manufactured at the time of manufacturing the second block 4. The open space in the second block 4 can be easily adjusted, and the manufacture of a highly accurate optical encoder is facilitated.
[0072]
According to this embodiment, since the optical reader 2 is separated into the first block 3 and the second block 4, the space in which the half mirror adhesion surface 421 and the V guide portion 413 in the second block main body 490 are opened. Accordingly, a mold used for resin molding of the second block main body 490 can be easily manufactured, and the half mirror adhesion surface 421 and the V guide portion 413 can be formed with high accuracy and easily.
[0073]
Next, a method for attaching the optical reader 2 to the circuit board 106 will be described. Returning to FIG. 8, holes corresponding to the first block substrate guide 303, the second block substrate guide 407, the light projection LED 310, the light projection amount monitor PD 320, and the pins of the photo IC 440 are formed in the circuit substrate 106. The circuit board 106 is moved in the D direction and attached to the optical reader 2, and the light projection LED 310, the light projection quantity monitor PD 320, and the photo IC 440 are electrically connected to the circuit board 106 by soldering.
[0074]
Next, a method for manufacturing the optical encoder 1 will be described. FIG. 15 is an explanatory diagram of a method for manufacturing the optical encoder 1. FIG. 15A is a diagram in which the reflecting plate 104 is attached to the shaft 101. The attachment method is as follows. First, the flange 100 is attached to the shaft 101, then the reflector 104 is inserted into the shaft 101, and then the reflector 104 is fixed to the shaft 101 with a retaining ring 112.
[0075]
FIG. 15B is a diagram in which the plate 105 is attached to the metal base 103 and the optical reader 2 is attached to the plate 105. Three plate support portions 111 for supporting the plate 105 protrude from the metal base 103, and the plate 105 is fixed to the three plate support portions 111 by screws. The plate 105 has holes at locations corresponding to the objective lens 410 of the optical reader 2 and locations corresponding to the bracket holes 403, and the optical reader 2 is fixed to the plate 105 by screws. The lengths of the three plate support portions 111 are equal so that the direction of the light projecting axis of the optical reader 2 is perpendicular to the reflecting plate 104.
[0076]
FIG. 15C is a diagram in which the circuit board 106 is attached to the board support rod 107. In addition to the hole corresponding to the optical reader 2 described above, the substrate is provided with a hole at a position corresponding to the substrate support rod 107 and is fixed to the substrate support rod 107 with screws. The circuit board 106 is provided with notches at locations corresponding to the electrical cord 109 and the bush 110. After the electrical cord 109 and the circuit board 106 are electrically connected, the metallic cylindrical case 108 (shown in FIGS. 1 and 2) is fixed to the metallic base 103 to obtain the optical encoder 1.
[0077]
FIG. 16 shows the optical reader 5 in the incremental and rotary optical encoder 1 according to the second embodiment of the present invention. 16A is a front view of the optical reader 5, and FIG. 16B is a cross-sectional view. The optical reader 5 has a structure in which the second block 4 in the optical reader 2 of the first embodiment is further divided into two blocks. The first block 3 is the same as that of the first embodiment, and an objective lens for both light projection and reception is used. 410, the half mirror 420, and a third block 6 comprising a third block body 690 for holding these optical components, and a fourth block body 790 comprising a light shielding plate 438, a photo IC 440 and these optical components. It consists of four blocks 7.
[0078]
17 is a diagram in which the first block 3, the third block 6, and the fourth block 7 are separated in the optical reader 5, FIG. 17 (a) is a front view, and FIG. 17 (b) is a cross-sectional view. is there. FIG. 18 is an external view of a state in which the first block 3, the third block 6, and the fourth block 7 are separated. 16 to 18, the same components as those shown in FIGS. 7 to 9 are given the same reference numerals, and a part of the description will be omitted.
[0079]
The difference between the optical reader 5 of the second embodiment and the optical reader 2 of the first embodiment is that a third block recess 601 is provided in the third block body 690 of the third block 6 in the second embodiment. The point, the light shielding plate 438 and the photo IC 440 are mounted on the second block 4 in the first embodiment, whereas the point mounted on the fourth block 7 in the second embodiment, and the light shielding plate 438 With shape. The shape of the light shielding plate 438 will be described in detail later.
[0080]
FIG. 19 is an assembly diagram of the fourth block 7, FIG. 19A is a diagram before assembly, and FIG. 19B is a diagram after assembly. First, the light shielding plate 438 is inserted into a slit hole provided on the side surface of the fourth block main body 790. The light shielding plate 438 has a slit pattern formed at the center like the light shielding plate 430 in the first embodiment, but the light shielding plate mounting hole is not provided on the outer side centering on the slit pattern, but at one end. A notch 433 is formed. The sectional shape of the slit hole is substantially the same as the sectional shape of the light shielding plate 438, and the light shielding plate 438 does not move in the fourth block body 790 after the light shielding plate 438 is inserted. The stopper 702 is a protrusion provided on one surface of the slit hole, and when the light shielding plate 438 is inserted, the stopper 702 is fitted to the notch 433 of the light shielding plate 438 to serve as a stopper. Next, the photo IC 440 is press-fitted and fixed to the photo IC insertion guide 703 of the fourth block body 790. A light receiving window 701 is provided on the surface of the fourth block main body 790 facing the third block main body 690. After the light blocking plate 438 and the photo IC 440 are attached to the fourth block main body 790, the light blocking plate 438 is exposed from the light receiving window 701. Further, the light receiving surface 442 of the photo IC 440 is exposed from the slit of the light shielding plate 438, and the light passing through the pinhole 401 of the third block 6 passes through the light receiving window 701 and the slit of the light shielding plate 438 to the photo IC 440. Led.
[0081]
Next, the manufacturing method of the optical reader 5 of the optical encoder 1 which is 2nd embodiment of this invention is demonstrated. First, the first block 3 and the third block 6 are manufactured, then the first block 3 and the third block 6 are combined, and finally the fourth block 7 is combined with the third block 6. Since the manufacturing method of the 1st block 3 was described by description of 1st embodiment, the description is abbreviate | omitted. The manufacturing method of the third block 6 and the method of combining the first block 3 and the third block 6 include the manufacturing method of the second block 4 of the first embodiment, the first block 3 and the second block 4. Since it is the same as the method of uniting, the description is abbreviate | omitted.
[0082]
Next, a method of combining the fourth block 7 with the third block 6 that has already been combined with the first block 3 will be described. Also in this case, the adjustment reflector 905 used in the first embodiment is used, and the light receiving circuit 450 is electrically connected to the photo IC 440, and an oscilloscope (not shown) is connected to the light receiving circuit 450.
[0083]
Here, the fourth block 7 is temporarily arranged in the third block recess 601 of the third block 6. Next, similarly to the manufacturing method of the first embodiment, the adjustment reflector 905 is rotated at 1500 rpm, the projection LED 310 is turned on, and the adjustment reflector 905 is projected. The reflected light is received by the photo IC 440. Here, the position of the fourth block 7 with respect to the third block recess 601 is adjusted while monitoring the electric signal from the amplified and waveform-shaped photo IC 440 using an oscilloscope, and a uniform sine waveform is obtained from the photo IC 440. After confirming that it has been obtained, the fourth block 7 is bonded and fixed to the third block recess 601.
[0084]
According to this embodiment, since the second block 4 in the optical reader 2 of the first embodiment is further divided into two blocks and divided into the third block 6 and the fourth block 7, the first block In addition to the effects of the embodiment, using the fourth block 7 on which the light shielding plate 438 and the photo IC 440 are mounted, the position can be easily adjusted with respect to the third block 6, and a highly accurate optical encoder can be manufactured. Becomes easy.
[0085]
Since the method of manufacturing the optical encoder 1 using the optical reader 5 of the second embodiment is the same as the method of manufacturing the optical encoder 1 using the optical reader 2 of the first embodiment, the description thereof is omitted. . The present invention has the same effect regardless of whether it is a rotary type / linear type or an incremental type / absolute type.
[0086]
【The invention's effect】
According to the present invention, the optical reader is configured to be separated into the first block and the second block, and the light source that may be relatively coarse in positioning adjustment is arranged in the first block, thereby achieving high-accuracy positioning. Since the required objective lens, light separator, light shielding plate, and light receiving element are integrated in the second block, a manufacturing process that does not require adjustment in the manufacturing process and a manufacturing process that requires high-precision positioning adjustment Therefore, it is possible to manufacture an efficient optical encoder.
[Brief description of the drawings]
FIG. 1 is an incremental and rotary optical encoder according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
FIG. 3 is a perspective view of the optical encoder with a case, an electric cord, and a bush removed.
FIG. 4 is a diagram showing a configuration mainly related to an optical reader and electrical processing in an optical encoder.
FIG. 5 is a front view of a reflecting plate.
6 is an enlarged view of a portion E in FIG.
FIG. 7 is an external view of an optical reader in an incremental and rotary optical encoder according to the first embodiment of the present invention.
8 is a cross-sectional view of the optical reader, and is a view seen from the direction B in FIG.
9A is a diagram in which the first block and the second block are separated from each other in FIG. 7, and is a view seen from the B direction. FIG. 9B is a diagram illustrating the first block and the second block in FIG. And are separated views.
FIG. 10 is a front view of a light shielding plate.
FIG. 11 is an external view of a state where a first block body and a second block body are separated in an optical reader in a state where an optical component such as an objective lens is not yet held.
12 shows a state where the optical component is held in FIG.
FIG. 13 is an explanatory view of a method of positioning and adjusting the objective lens to the V guide part and bonding and fixing it, and is a view of the second block as seen from the back surface of the mounting bracket.
FIG. 14 is an explanatory view of a method for positioning and adjusting an objective lens to a V guide portion, and is a view seen from a side surface direction of the objective lens in a sectional view of a second block.
FIG. 15 is an explanatory diagram of a method for manufacturing an optical encoder.
FIG. 16 shows an optical reader in an incremental and rotary optical encoder according to a second embodiment of the present invention.
FIG. 17 is a diagram in which the first block, the third block, and the fourth block are separated in the optical reader.
FIG. 18 is an external view of a state in which a first block, a third block, and a fourth block are separated.
FIG. 19 is an assembly drawing of the fourth block.
[Explanation of symbols]
1 Optical encoder
2 Optical reader of the first embodiment
3 First block
4 Second block
5 Optical reader of the second embodiment
6 Third block
7 Fourth block
100 flange
101 shaft
102 Bearing
103 base
104 reflector
105 plates
106 Circuit board
107 Substrate support rod
108 cases
109 Electrical cord
110 Bush
111 Plate support
112 retaining ring
120 reflection band
121 shaft hole
122 First reflection band
123 Second reflection band
124 Third reflection band
301 1st block coalesced projection
302 First block merged surface
303 First block board guide
310 Flood LED
311 Projection LED insertion hole
312 projection LED press-fitting projection
320 Light emission monitor PD
321 Light emission monitor PD insertion hole
330 Light Emitting Circuit
390 1st block body
401 pinhole
402 Mounting bracket
403 Bracket hole
404 Bracket rib
405 Second block coalescing protrusion
406 Second block merged surface
407 Second block board guide
410 Objective lens
411 Cylindrical outer peripheral surface
412 recess
413 V guide section
414 Lens Guide
420 half mirror
421 Half mirror adhesive surface
430 Shading plate of the first embodiment
431 Shading plate mounting hole
432 Shading plate mounting part
433 Notch
434 1st slit row
435 Second slit row
436 3rd slit row
437 4th slit row
438 Shading plate of second embodiment
440 Photo IC
441 Photo IC insertion guide of the first embodiment
442 Photosensitive surface
450 Light receiving circuit
451 Signal processor
452 Output circuit
490 Second block body
601 Third block recess
690 Third block body
701 Light receiving window
702 Stopper
703 Photo IC insertion guide of second embodiment
790 The fourth block body
900 Jig for slide adjustment
901 lever
902 Slide jig protrusion
903 Slit plate for adjustment
904 CCD for positioning adjustment
905 Reflector for adjustment

Claims (10)

A reflection plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, and a reflection type optical reading that irradiates light to the reflection plate and detects regular reflection light from the reflection plate. An optical encoder configured to output a corresponding electrical signal from the optical reader with relative movement between the reflector and the optical reader,
The optical reader comprises a first block and a second block;
The first block includes a light source that irradiates light to the reflector.
The second block irradiates the reflecting plate with light from the light source as parallel rays so as to include a group of regular reflection portions and non-regular reflection portions, and also reflects regular reflection light from the reflection plate. An objective lens for condensing light emitting and receiving; and
A light-shielding plate having a slit pattern disposed at the imaging position of the return path light returning from the objective lens and corresponding to a group of regular reflection portions and non-regular reflection portions;
A light separator that directs forward light from the light source to the objective lens and directs return light from the objective lens to the light shielding plate;
A light receiving element that receives light transmitted through the slit pattern behind the light shielding plate;
An optical encoder further comprising: a pinhole disposed at a focal position of the objective lens in front of the optical path of the return path light separated via the optical separator. The second block is opened so that at least a part of the side surface of the objective lens is exposed;
A lens guide that is slidably supported in the principal axis direction of the objective lens;
The optical separator according to claim 1, further comprising: a light separator holding surface that holds the light separator with an inclination of about 45 degrees with respect to a principal axis direction of the objective lens, and the light separator holding surface is opened. Type encoder. The second block is formed by resin molding,
The optical encoder according to claim 1 or 2, wherein the pinhole is formed integrally with the second block by the resin molding. The second block holds the objective lens and the light separator;
And a third block with the pinhole,
4. The optical encoder according to claim 1, comprising a fourth block for holding the light shielding plate and the light receiving element. Centering on the third block, the first block is joined to the holding surface side holding the light separator on the third block,
5. The optical encoder according to claim 4, wherein the fourth block is formed on a side opposite to a holding surface that holds the light separator around the pinhole of the third block. A reflector in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction;
A reflection-type optical reader that irradiates light to the reflection plate and detects specularly reflected light from the reflection plate, and the optical reading is performed with relative movement between the reflection plate and the optical reader. An optical encoder configured to output a corresponding electrical signal from the device,
The optical reader is
A light source that emits light to the reflector;
Combined light projection and reception for irradiating spotlight so that a group of regular reflection parts and non-regular reflection parts are included on the reflection plate as parallel light rays from the light source and condensing regular reflection light from the reflection plate Objective lens,
A light-shielding plate having a slit pattern disposed at the imaging position of the return path light returning from the objective lens and corresponding to a group of regular reflection portions and non-regular reflection portions;
A light separator that directs forward light from the light source to the objective lens and directs return light from the objective lens to the light shielding plate;
A light receiving element that receives light transmitted through the slit pattern behind the light shielding plate;
A pinhole disposed at the focal position of the objective lens in front of the optical path of the return path light separated via the light separator;
The mounting portion of the optical reader comprising a substantially flat plate portion formed so as to extend in a direction perpendicular to the main axis direction of the objective lens, wherein the mounting surface of the optical reader in the flat plate portion is the main shaft of the objective lens An optical encoder comprising a mounting portion that is perpendicular to the direction. Irradiate light to a reflection plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, optically read the regular reflection light from the reflection plate, and move relative to the reflection plate A reflection-type optical reader used in an optical encoder that outputs a corresponding electrical signal.
The reflective optical reader includes a first block and a second block,
The first block includes a light source that irradiates light to the reflector.
The second block irradiates the reflecting plate with light from the light source as parallel rays so as to include a group of regular reflection portions and non-regular reflection portions, and also reflects regular reflection light from the reflection plate. An objective lens for condensing light emitting and receiving; and
A light-shielding plate having a slit pattern disposed at the imaging position of the return path light returning from the objective lens and corresponding to a group of regular reflection portions and non-regular reflection portions;
A light separator that directs forward light from the light source to the objective lens and directs return light from the objective lens to the light shielding plate;
A light receiving element that receives light transmitted through the slit pattern behind the light shielding plate;
A reflective optical reader, further comprising: a pinhole disposed at the focal position of the objective lens in front of the optical path of the return path light separated via the optical separator. The second block holds the objective lens and the light separator;
And a third block with the pinhole,
8. The reflective optical reader according to claim 7, comprising a fourth block that holds the light shielding plate and the light receiving element. The second block includes a mounting portion of the optical reader composed of a substantially flat plate portion formed so as to extend in a direction perpendicular to the principal axis direction of the objective lens.
The reflective optical reader according to claim 7 or 8, wherein a mounting surface of the optical reader in the flat plate portion is perpendicular to a main axis direction of the objective lens. Irradiate light to a reflection plate in which regular reflection portions and non-regular reflection portions are alternately formed along a predetermined direction, optically read the regular reflection light from the reflection plate, and move relative to the reflection plate A reflection-type optical reader used in an optical encoder that outputs a corresponding electrical signal.
A light source that emits light to the reflector;
Combined light projection and reception for irradiating spotlight so that a group of regular reflection parts and non-regular reflection parts are included on the reflection plate as parallel light rays from the light source and condensing regular reflection light from the reflection plate Objective lens,
A light-shielding plate having a slit pattern disposed at the imaging position of the return path light returning from the objective lens and corresponding to a group of regular reflection portions and non-regular reflection portions;
A light separator that directs forward light from the light source to the objective lens and directs return light from the objective lens to the light shielding plate;
A light receiving element that receives light transmitted through the slit pattern behind the light shielding plate;
A pinhole disposed at the focal position of the objective lens in front of the optical path of the return path light separated via the light separator;
A mounting portion of the optical reader comprising a substantially flat plate portion formed so as to extend in a direction perpendicular to the main axis direction of the objective lens, wherein the mounting surface of the optical reader in the flat plate portion is a main shaft of the objective lens. A reflective optical reader comprising a mounting portion that is perpendicular to the direction.

Images