JP2004301826A - Optical encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical rotary encoder that can quickly cope with an arbitrary angular resolution or graduation pattern and is easily applicable to wide-variety and small-quantity production. <P>SOLUTION: The optical rotary encoder is provided with a rotary disc with graduations formed around its circumference, a light projection part, a lens, an optical reader that is provided with a light receiving part and reads out a graduation from the rotary disc, an a light shielding plate that is arranged before the light receiving part and wherein slits corresponding to the graduations on the rotary disc are formed. It reads graduations formed on the rotary disc by collimating light from the light projection part by the lens and emitting them to the rotary disc. A scale plate (1) is manufactured by emitting a laser beam to a scale plate material while it is placed on XYθ tables (711, 712, 713) of a laser machining device (710), controlling the movement of the XYθ tables appropriately, and forming graduations on the scale plate material. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention provides, for example, an absolute type or increment type optical rotary encoder for detecting a rotation angle, a rotation speed, a rotation speed, etc., and an absolute type for detecting the length of a detection target object, a linear movement distance, etc. And an incremental optical linear encoder.

  As is well known to those skilled in the art, an optical encoder is a rotary encoder for detecting a rotation angle, a rotation speed, a rotation speed, and the like, and a length of a detection target, a linear movement distance, and the like (Hereinafter collectively referred to as an optical encoder). The optical encoder consists of a scale plate (rotary plate for a rotary encoder, linear scale for a linear encoder) with an engraved scale, an optical reader for reading the scale from the scale plate, and an optical reader. A light-shielding plate disposed on the front surface and formed with slits corresponding to the scales on the scale plate. The structure of the scale plate differs depending on the optical reading method of the optical encoder. When the reading method of the optical reader is a transmission type, the scale portion on the scale plate has a structure capable of transmitting light. Similarly, when the reading method of the optical reader is a reflection type, the scale portion on the scale plate has a structure capable of reflecting light. On the other hand, each slit portion on the light shielding plate has a structure that transmits light. Here, the term “permeate” may be a through hole or a transparent portion.

  In addition, an increment method and an absolute method are known for this type of optical encoder. In the case of the increment method, the scales are arranged at almost equal intervals. On the other hand, in the case of the absolute method, it is composed of a multi-bit code corresponding to each resolution.

Conventionally, as a technique for engraving a scale on a scale plate, stamping or photo-etching is known. By forming a metal vapor deposition film on the surface of the transparent substrate, forming a light shielding film made of a photosensitive agent on the surface of the metal vapor deposition film, and etching the light shielding film, an optical system defined by the exposed portion of the metal vapor deposition film It is known to form an encoder light reflection pattern (see Patent Document 1).
Japanese Patent Laid-Open No. 10-82661

  However, in the case of the conventional scale plate, in the case of punching molding, the mold must be designed and manufactured, whereas in the case of using photo-etching, the mask must be designed and manufactured. It has been pointed out that it takes time from ordering to shipping, it takes a lot of money to design and produce molds and masks, and it cannot cope with high-mix low-volume production due to cost. Yes.

  The present invention has been made paying attention to such conventional problems, and the object of the present invention is to be able to respond quickly to any resolution or scale pattern, and to be suitable for high-mix low-volume production. Another object of the present invention is to provide an easy optical encoder.

  Another object of the present invention is to provide an optical encoder that can realize high resolution or scale pattern accuracy.

  Other objects and operational effects of the present invention will be easily understood by those skilled in the art by referring to the following description of the specification.

  An optical rotary encoder according to a first embodiment of the present invention includes an optical reading device that reads a scale from a rotating plate that includes a rotating plate engraved with a scale along a circle, a light projecting element, a lens, a light shielding plate, and a light receiving element. And a light-shielding plate disposed on the front surface of the optical reader and formed with a slit corresponding to the scale on the rotating plate, and collimates the light from the light projecting element with the lens and irradiates the rotating plate. This is to read the scale carved on the rotating plate. In addition to the above basic configuration, the greatest feature of the optical rotary encoder of the present invention is that the scale on the rotating plate is carved by laser irradiation.

  According to such a configuration, the laser beam is irradiated onto the rotating plate using a laser processing machine, and the scale is engraved on the rotating plate. Therefore, it is not necessary to design and manufacture a molding die or an etching mask. The time to reach can be greatly shortened. In addition, since the cost for designing and manufacturing the molding die and the etching mask is not required, this can be realized at a low cost even in the case of multi-product small-volume production. In addition, when the scale is engraved by laser irradiation compared to the case where the scale is engraved by a molding die or photoetching, the scale is engraved more accurately than the previous method depending on the control of the laser processing machine. be able to.

  In a preferred embodiment of the optical rotary encoder of the present invention, the slit on the light shielding plate can also be engraved by laser irradiation. Here, in the basic invention of the optical rotary encoder, the laser processing of the slit on the light shielding plate is not included for the following reason. That is, in this type of optical rotary encoder, the diameter of the rotating plate varies depending on the required resolution. On the other hand, the slit on the light shielding plate is strictly one-to-one with the rotating plate. There is no need to correspond, and a common light shielding plate can be used for a certain range of pitches on the rotating plate. Therefore, the slits on the light shielding plate are not necessarily aligned with the scale pitch on the rotating plate. This is because it is not necessary to remake each time.

  In the preferred embodiment of the optical rotary encoder of the present invention, the reading method of the rotating plate is limited to the reflection type. Various methods are also possible for the method of engraving the scale by laser irradiation. However, when the reading method on the rotating plate is a reflection type, for example, a predetermined portion of a metal having a mirror-like surface is irradiated with a laser to roughen the surface. This is because the scale can be engraved on the rotating plate by a simple method such as facing or depositing a metal film on the glass plate by vacuum deposition or the like and removing it by laser irradiation.

  In the preferred embodiment of the optical rotary encoder of the present invention, the scale shape on the rotating plate can be a trapezoid. In such a trapezoidal scale, when applied to a laser processing machine equipped with X, Y, and θ independent stages, pitches in the θ direction that are difficult to control and difficult to move are intermittently fed. This is because the trapezoidal scale along the scale shape can be engraved with high precision by finely controlling only the X and Y stages.

  In addition, this invention seen from another one side can also be grasped | ascertained as a rotating plate for optical rotary encoders. Even in such a rotating plate, the scale is engraved on the rotating plate along a circle by laser irradiation. At this time, as described above, the reading method of the rotary plate can be a reflection type, and the scale can be trapezoidal. The effects of these individual elements are the same as those described above. Furthermore, the present invention viewed from another aspect can be regarded as a light shielding plate for an optical rotary encoder. Even in such a light shielding plate, slit rows are engraved in a predetermined pattern on the light shielding plate by laser irradiation.

  Furthermore, the present invention viewed from another aspect can be understood as a method for manufacturing a rotary plate for an optical rotary encoder. In the manufacturing method of the present invention, in a state where the rotating plate material is set on the XYθ table of the laser processing apparatus, the movement of the XYθ table is appropriately controlled while irradiating the laser beam to the rotating plate material, and the scale is formed on the rotating plate material. I'm trying to carve along a circle. According to such a method, a molding die and an etching mask are not required, and therefore, a large variety of small-scale production of a rotary plate for an optical rotary encoder is possible.

  At this time, if the laser beam irradiation coordinates are calculated based on the required outer shape and resolution of the rotating plate, and the movement of the XYθ table is controlled based on the calculated coordinates, a scale plate of any specification can be manufactured. .

  Further, if only the XYθ table is controlled to move while the optical axis declination of the laser beam is fixed, high-precision processing can be performed while suppressing beam wobbling. Also, the rotational movement of the θ table is performed intermittently, while the movement of the XY table is performed continuously, so that the scale processing accuracy of the scale can be improved if a trapezoidal scale is engraved on the rotating plate material along a circle. Can increase the processing time.

  Various materials can be used as the rotating plate material. For example, a rotating plate material may be a metal plate in which only a laser processing region is a thin region, and a laser beam is selectively irradiated to form a through hole. Thereby, the ease of processing can be improved while maintaining rigidity as a whole. Further, the rotating plate material is a transparent substrate having a surface coated with a highly reflective or light-shielding metal coating, and a transparent hole is formed by selectively irradiating a laser beam on the substrate to remove the highly reflective metal coating. Can also be formed. As a result, it is possible to adopt a chromium vapor deposition film or the like as the metal coating, and it is possible to make a scale marking without increasing the laser output so much. In addition, a rotating plate material may be a metal plate whose surface is a mirror surface, and a laser beam is selectively irradiated to form a rough surface region. Thereby, a reflection type rotating plate can be manufactured easily.

  Furthermore, the present invention viewed from another aspect can be regarded as a method for manufacturing a light shielding plate for an optical rotary encoder. In the manufacturing method of the present invention, in a state where the light shielding plate material is set on the XYθ table of the laser processing apparatus, the movement of the XYθ table is appropriately controlled while irradiating the laser beam on the table, and a through slit is formed on the light shielding plate material. Alternatively, a transparent slit row is engraved. Thereby, a light-shielding plate can be manufactured at low cost. Note that, with respect to the light shielding plate, if the movement of the XYθ table is controlled while the optical axis declination of the laser beam is fixed, high-precision processing can be performed while suppressing beam wobbling. In addition, the rotational movement of the θ table is performed intermittently, while the movement of the XY table is performed continuously, so that a trapezoidal scale is engraved on the light shielding plate material along a circle, so that the processing accuracy of the slit row is improved. And the processing time can be shortened.

  Various materials can be adopted as the light shielding plate material for the rotary encoder. For example, the light shielding plate material may be a metal plate in which only a laser processing region is a thin region, and a laser beam is selectively irradiated to form a through hole. Thereby, the ease of processing can be improved while maintaining rigidity as a whole. In addition, a transparent substrate is formed by applying a highly reflective metal coating on the surface of the light shielding plate material, and a transparent hole is formed by selectively irradiating a laser beam on the transparent substrate to remove the highly reflective metal coating. Is mentioned. As a result, it is possible to adopt a chromium vapor deposition film or the like as the metal coating, and it is possible to make a scale marking without increasing the laser output so much.

  Next, an optical linear encoder according to a second embodiment of the present invention includes a linear scale whose scale is engraved along a straight line, a light projecting element, a lens, a light shielding plate, and a light receiving element, and reads the scale from the linear scale. The linear scale has an optical reader and a light-shielding plate disposed on the front surface of the optical reader and formed with a slit corresponding to the scale on the linear scale, and collimates the light from the light projecting element with a lens. The scale engraved on the linear scale is read by irradiating an arbitrary area. In addition to the above basic configuration, the greatest feature of the optical linear encoder of the present invention is that the scale on the linear scale is carved by laser irradiation.

  According to such a configuration, laser irradiation is performed on a linear scale using a laser processing machine, and a scale is engraved on the linear scale. Therefore, there is no need to design and manufacture a molding die or an etching mask, and from order receipt to shipment. The time to reach can be greatly shortened. In addition, since the cost for designing and manufacturing the molding die and the etching mask is not required, this can be realized at a low cost even in the case of multi-product small-volume production. In addition, when the scale is engraved by laser irradiation compared to the case where the scale is engraved by a molding die or photoetching, the scale is engraved more accurately than the previous method depending on the control of the laser processing machine. be able to.

  In a preferred embodiment of the optical linear encoder of the present invention, the slit on the light shielding plate can also be engraved by laser irradiation. Here, in the basic invention of the optical linear encoder, the laser processing is not included for the slit on the light shielding plate for the following reason. That is, in this type of optical linear encoder, the scale pitch on the linear scale varies depending on the required resolution. On the other hand, the slit on the light shielding plate has a one-to-one relationship with the linear scale. It is not necessary to correspond exactly, and a common shading plate can be used for a certain range with a pitch on the linear scale, so the slit on the shading plate is not necessarily matched to the scale pitch on the linear scale. This is because there is no need to remake each time.

  In the preferred embodiment of the optical linear encoder of the present invention, the reading method of the rotating plate is limited to the reflection type. Various methods are also possible for the method of engraving the scale by laser irradiation. However, when the reading method on the linear scale is a reflection type, for example, a predetermined portion of a metal having a mirror-like surface is irradiated with a laser to roughen the surface. This is because the scale can be engraved on the linear scale by a simple method such as facing or depositing a metal film on a glass plate by vacuum vapor deposition or the like and removing it by laser irradiation.

  The present invention viewed from another aspect can also be understood as a linear scale for an optical linear encoder. Even in such a linear scale, scales are engraved on the linear scale along a circle by laser irradiation. At this time, as described above, the linear scale reading method may be a reflection type. About the effect by it, it is the same as that of what was described previously. Furthermore, the present invention viewed from another aspect can be regarded as a light shielding plate for an optical linear encoder. Even in such a light shielding plate, slit rows are engraved in a predetermined pattern on the light shielding plate by laser irradiation.

  Furthermore, the present invention viewed from another aspect can be understood as a method for manufacturing a linear scale for an optical linear encoder. In the manufacturing method of the present invention, in a state where the linear scale material is set so as to be able to be fed to the XY table of the laser processing apparatus, the movement of the XY table and the feed operation of the linear scale material are appropriately performed while irradiating the laser beam to the linear scale material. The scale is engraved along a straight line on the linear scale material. According to such a method, a molding die and an etching mask are not required, so that a large variety of small-scale production of a linear scale for an optical linear encoder is possible.

  At this time, if only the movement control of the XY table and the dimension feed operation control of the linear scale material are performed while the optical axis deflection angle of the laser beam is fixed, high-precision processing can be performed while suppressing the beam wobbling. In addition, the linear scale material is moved intermittently while the XY table is moved continuously, so that the scale processing accuracy can be improved if the scale is engraved on the linear scale material along a straight line. And processing time can be shortened.

  Various materials can be adopted as the linear scale material. For example, a linear scale material may be a metal plate in which only a laser processing region is a thin region, and a laser beam is selectively irradiated to form a through hole. Thereby, the ease of processing can be improved while maintaining rigidity as a whole. In addition, the linear scale material is a transparent substrate with a highly reflective or light-shielding metal coating on the surface, and a laser beam is selectively irradiated to the transparent substrate to remove the highly reflective metal coating. Can also be formed. As a result, it is possible to adopt a chromium vapor deposition film or the like as the metal coating, and it is possible to make a scale marking without increasing the laser output so much. Further, a linear scale material may be a metal plate having a mirror surface, and a laser beam may be selectively irradiated to form a rough surface region. Thereby, a reflective linear scale can be manufactured easily.

  Furthermore, the present invention viewed from another aspect can be understood as a method for manufacturing a light shielding plate for an optical linear encoder. The manufacturing method of the present invention appropriately moves the XY table and moves the light shielding plate material while irradiating the laser beam to the light shielding plate material in a state where the light shielding plate material is set on the XY table of the laser processing apparatus. The through slit or the transparent slit row is engraved on the light shielding plate material. Thereby, a light-shielding plate can be manufactured at low cost. For the light shielding plate, if only the movement control of the XY table and the dimension feed operation control of the light shielding plate material are performed while the optical axis declination of the laser beam is fixed, high accuracy can be achieved by suppressing beam wobbling. Can be processed. In addition, the shading plate material is moved intermittently while the XY table is moved continuously, so that if the scale is engraved on the light shielding plate material along a straight line, the processing accuracy of the slit row can be improved. Can increase the processing time.

  Various materials can be adopted as the light shielding plate material for the linear encoder. For example, the light shielding plate material may be a metal plate in which only a laser processing region is a thin region, and a laser beam is selectively irradiated to form a through hole. Thereby, the ease of processing can be improved while maintaining rigidity as a whole. In addition, a transparent substrate is formed by applying a highly reflective metal coating on the surface of the light shielding plate material, and a transparent hole is formed by selectively irradiating a laser beam on the transparent substrate to remove the highly reflective metal coating. Is mentioned. As a result, it is possible to adopt a chromium vapor deposition film or the like as the metal coating, and it is possible to make a scale marking without increasing the laser output so much.

  As is apparent from the above description, according to the present invention, there is an advantage that high-mix low-volume production is possible at a low cost of an optical encoder of a reflection type or a transmission type, or an absolute type or an increment type.

  In the following, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. The embodiment described below is merely an example of the present invention, and the gist of the present invention is defined only by the description of the claims.

  In the embodiments of the invention described below, first, an optical rotary encoder according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 12, and then, with reference to FIGS. The optical linear encoder according to the second embodiment will be described in order.

  The optical rotary encoder according to the first embodiment of the present invention includes both a reflection type and a transmission type.

  FIG. 1 shows the external appearance of the optical rotary encoder when the outer case is removed. In the figure, a reflection type is shown as an example. An optical rotary encoder 1000 shown in this example includes a disc-shaped rotating plate 1a, a shaft 2 that is fixedly penetrated at the center of the rotating plate 1a, a bearing 3 that supports the shaft 2, and a light projecting element that will be described later. , An optical reader (optical module) 52 having a lens, a light receiving element, etc., a mounting base 51 for mounting the optical reader 52, and a signal generated by the optical reader 51 to the outside And a circuit board 53 for taking out.

  A detailed configuration of a reflective optical rotary encoder according to an embodiment of the present invention is shown in FIG. In the reflective optical rotary encoder, the shaft 2 constitutes a detection axis and is coupled to a detection target.

  When the light projecting circuit 4 is activated, the light projecting element 5 is driven. The light beam L11 emitted from the light projecting element 5 passes through the half mirror 6 while maintaining a constant spread angle, is converted into parallel light by the lens 7, and is irradiated onto the surface of the rotating plate 1a. The light reflected by the surface of the rotating plate 1 a passes through the lens 7, is reflected by the half mirror 6, and travels toward the light receiving element 9. On the front side of the light receiving element 9, a light shielding plate 8 provided with a slit to be described later is disposed. The light beam L12 reflected by the half mirror 6 enters the light receiving element 9 through the slit of the light shielding plate 8. The electrical signal generated by the light receiving element 9 is amplified and waveform shaped by the light receiving circuit 10 and then sent to the signal processing unit 11. The signal processing unit 11 generates and outputs a pulse train corresponding to the angular resolution in the case of an incremental rotary encoder, and generates a code signal corresponding to each angular position in the case of an absolute rotary encoder. The signal thus obtained from the signal processing unit 11 is sent to the outside via the output circuit 12. The above is the basic configuration and operation of the reflective optical rotary encoder.

  FIG. 3 shows a detailed configuration of a transmissive optical rotary encoder which is an embodiment of the present invention. The configuration and operation of the transmissive optical rotary encoder are basically the same as those of the reflective optical rotary encoder shown in FIG. Only the differences will be described. In the figure, the same components as those in FIG.

  The transmissive rotary plate 1b has a structure that transmits light corresponding to the scale portion. The light beam L21 emitted from the light projecting element 5 is irradiated onto the lens 7 while maintaining a certain spread angle, and is converted into parallel light L22. Thereafter, the light beam L22 passes through the rotating plate 1b and travels toward the light receiving element 9 provided on the opposite side to the light projecting element 5 with the rotating plate 1b interposed therebetween. On the front side of the light receiving element 9, a light shielding plate 8 provided with a slit to be described later is disposed. When the light receiving element 9 is irradiated with the light beam L22 after passing through the light shielding plate 8, a corresponding electrical signal is sent from the light receiving element 9. As described above with reference to FIG. 2, this electrical signal is sent to the outside through the light receiving circuit 10, the signal processing unit 11, and the output circuit 12. The above is the basic configuration and operation of the transmissive optical rotary encoder.

  In the optical rotary encoder of the present invention, in the above configuration, the rotation plates 1a and 1b and the light shielding plate 8 are devised. More specifically, the rotating plates 1a and 1b and the light shielding plate 8 are manufactured using a laser processing machine. FIG. 4 shows a front view of an example of a reflection type or transmission type incremental rotating plate.

  As shown in the figure, the rotary plate 1 is formed in a disk shape, and a scale array band 13 is provided at the peripheral portion thereof, and a shaft hole 14 for penetrating and fixing the shaft 2 is formed at the center portion. It has been established.

  An enlarged view of part A in FIG. 4 is shown in FIG. As shown in the figure, the scale row 13 is composed of three scale rows including a first scale row 13a, a second scale row 13b, and a third scale row 13c. As will be described later, these scale rows are formed using a laser processing machine. That is, the scale is engraved by laser irradiation instead of punching or photoetching as in the conventional rotating plate. The second scale row 13b is an A-phase pattern and a B-phase pattern for outputting a pulse train as an incremental rotary encoder and detecting the rotation direction of the rotating plate 1. The first scale row 13a and the third scale row 13c are Z-phase patterns for detecting the origin position.

  On the other hand, an example of the light shielding plate 8 of the optical rotary encoder of the present invention is shown in FIGS. In these drawings, reference numeral 7 is a light shielding plate, 81 and 82 are positioning holes for attaching the light shielding plate to a laser processing machine to be described later, 83 is a thick region, 84 is a thin region, and 85 is a thick region and a thin wall. A boundary line with the region, 86a is a first slit row, 86b is a second slit row, 86c is a third slit row, and 86d is a fourth slit row.

  The structure of the light shielding plate of the optical rotary encoder of the present invention and the manufacturing process for engraving the scale will be described in detail later, but only the slit arrangement on the light shielding plate will be described here. The arrangement of the slit rows is irrelevant to the cross-sectional structure and material of the light shielding plate, and is common to the light shielding plates of any optical rotary encoder.

  That is, as shown in FIG. 7, four slit rows, which are a first slit row 86a, a second slit row 86b, a third slit row 86c, and a fourth slit row 86d, are formed in the central portion of the light shielding plate. Has been. Each of the slits constituting the slit row is a through hole or a transparent hole, and light can pass through only the slit portion. These slit rows have a certain relationship with the scale rows of the rotating plate 1 shown in FIGS.

  Next, FIG. 9 shows an explanatory diagram of a method for processing the rotating plate and the light shielding plate of the optical rotary encoder of the present invention. 2A and 2B show the cross-sectional structure of the rotating plate 1, and FIG. 2C and FIG. 2D show the cross-sectional structure of the light shielding plate 8.

  First, a cross-sectional structure (part 1) of the rotating plate shown in FIG. The rotating plate shown in this example can be applied to a reflective optical rotary encoder. This rotating plate is formed by selectively irradiating the metal substrate 100 having a mirror surface with a laser beam to roughen the surface, thereby forming regular reflection portions and irregular reflection portions. For example, stainless steel (SUS) is used as the metal substrate 100, and the thickness d1 is about 100 μm. In the figure, reference numeral 100a denotes a mirror surface area, and reference numeral 100b denotes a rough surface area. The mirror surface region 100a is an exposed surface of the metal substrate 100 as it is, and the rough surface region 100b is a portion roughened by laser irradiation. According to such a configuration, the light beam L1 irradiated from the light projecting element to the rough surface area 100b is scattered and hardly returns to the light receiving element, whereas the light beam irradiated from the light projecting element to the mirror surface area 100a. L2 is regularly reflected and most of the light returns to the light receiving element. The mirror surface area 100a corresponds to the scale area a in the enlarged view of the portion A in FIG. On the other hand, the rough surface region 100b corresponds to the peripheral region b in the enlarged view of the portion A in FIG. Therefore, the surface of the rotating plate is irradiated with light from the light projecting element, and the reflected light is photoelectrically converted to correspond to the first scale row 13a, the second scale row 13b, and the third scale row 13c. An electrical signal can be acquired.

  Next, the sectional structure (part 2) of the rotating plate shown in FIG. The rotating plate shown in this example can be applied to both a reflection type and a transmission type. This rotating plate has a transparent substrate 110 and a metal thin film 120 deposited on the surface thereof. As a material of the transparent substrate 110, glass, plastic, or the like can be used. On the other hand, as a material of the metal thin film 120, a highly reflective metal material such as chromium (Cr) can be employed. In this example, a disk-shaped material in which a metal thin film (chromium vapor deposition film) 120 is deposited on the surface of a transparent substrate (glass plate) 110 is prepared, and the surface is selectively irradiated with a laser beam. Thus, the metal thin film 120 is selectively removed (sublimation removed) to form the thin film removal region 120a. According to such a configuration, the light beam L3 irradiated from the light projecting element to the mirror surface (region where the thin film is not removed) of the metal thin film 120 is regularly reflected and returned to the light receiving element. The light beam L4 applied to the removal region 120a passes through the transparent substrate 110 and is hardly returned to the light receiving element. When this rotating plate is used as a reflection type, the mirror surface of the metal thin film 120 is a scale area a in the enlarged view of the portion A in FIG. On the other hand, the thin film removal region 300a is a peripheral region b in the enlarged view of the portion A in FIG. On the other hand, when this rotating plate is used as a transmission type, the thin film removal region 120a is a scale region a in the enlarged view of the A portion of FIG. 5, and conversely, the rough surface of the metal thin film 120 is a peripheral region b. . When a glass plate is used as the transparent substrate 120, it is preferable to adopt B270 when the reflective type is used, and BK-7 when the transmissive type is used. Since BK-7 has a high transmittance, BK-7 is superior in the transmission type. On the other hand, in the case of a reflective type that does not require consideration of the transmittance, it is preferable to adopt B270 having a low cost. When glass is used as the transparent substrate 110, the thickness d2 is about 1.1 mm. On the other hand, when a chromium deposition film is used as the metal thin film 120, the thickness d3 of the chromium deposition film is about 1400 mm. It is said.

  Next, the sectional structure (No. 1) of the light shielding plate of the optical rotary encoder shown in FIG. In this example, the light shielding plate is mainly composed of a thin metal plate 130. On the surface of the thin metal plate 130, an electroformed metal layer 140 is grown while leaving a thin region 150 to be laser processed. For example, nickel (Ni) is used as the material of the metal thin plate 130, and similar nickel (Ni) is used as the electroformed metal layer 140. The thickness d4 of the thin region 150 is about 0.01 mm, and the thickness d5 of the electroformed metal layer 140 is about 0.04 mm. Therefore, the total thickness of the thick portion is about 0.05 mm.

  The example shown in FIG. 9C corresponds to the light shielding plate 8 of the optical rotary encoder shown in FIGS. That is, in this example, the thin area 84 surrounded by the boundary line 85 in a rectangle shown in FIG. 6 becomes the thin area 150, and the thick area 83 in the peripheral portion is grown and formed by the electroformed metal layer 140. Prepare a shading plate that will be the area.

  The light shielding plate is fixed via positioning holes 81 and 82 on a stage of a laser processing machine of an optical rotary encoder which will be described in detail later. Thereafter, by irradiating a laser beam into the thin region 84, as shown in FIG. 7, the first slit row 86a, the second slit row 86b, the third slit row 86c, and the fourth slit row 86d are shown. As described above, the slit rows are formed through the laser beam. As shown in FIG. 9C, the portion irradiated with the laser beam becomes a perforated region 130a, while the metal thin plate 130 is left as it is in the portion not irradiated with the laser beam. Here, the perforated region 130a corresponds to the slit region c in the enlarged view of FIG. On the other hand, the surface of the light-shielding metal thin plate 130 corresponds to the peripheral region d in the enlarged view of FIG. As is clear from FIG. 9C, the light beam L5 irradiated to the perforated region 130a escapes to the opposite side, whereas the light beam L6 irradiated to the metal thin plate 130 is reflected and returned.

  Next, a cross-sectional structure (No. 2) of the light shielding plate of the optical rotary encoder shown in FIG. In this example, a transparent substrate (glass or plastic) 111 and a metal thin film (such as a chromium vapor deposition film) 121 deposited on the transparent substrate 111 are provided. Then, by removing the metal thin film 121 by selective irradiation with a laser beam, the light shielding plate 8 is manufactured by forming the thin film removal region 121a. When a glass plate is used as the transparent substrate 111, the thickness d6 is about 0.5 to 1.2 mm, and when a chromium vapor deposition film is used as the metal thin film 121, the thickness d7 completely absorbs light. It is set to about 1400 mm so that it can be shut off. Here, the region where the metal thin film 121 is deposited corresponds to the peripheral region d in the enlarged view of FIG. 8, and the thin film removal region 121a corresponds to the slit region c.

  Next, the block diagram of the laser processing system of the optical rotary encoder of the present invention is shown in FIG. As shown in the figure, the laser processing system 700 includes a laser processing device 710, an arithmetic processing device 720, and a visual recognition device 730.

  The laser processing apparatus 710 has a work set / control stage for positioning the work W. This control stage has an X table 711 responsible for movement in the X direction, a Y table 712 responsible for movement in the Y direction, and a θ table 713 responsible for movement in the θ direction (rotation direction). Then, the workpiece W is placed and fixed on the θ table 713. In the present invention, the work W is the rotating plate 1 or the light shielding plate 8.

  The laser device 716 includes a power supply device 717 and a cooling device 718, and is configured by a YAG laser (in this example, second harmonic: 532 nm, output: about 0.5 mJ, repetition frequency: 5 to 40 kHz). The laser beam emitted from the laser device 716 is reflected by the mirror 715, condensed through the condenser lens 714, and then irradiated onto the surface of the workpiece W. Particularly in this example, in order to enable precise machining, the galvano mirror included in a normal laser processing machine of this type is fixed, and all beam operations on the workpiece W are borne by the control stage side. It has become so. In other words, by fixing the laser beam so that it does not fluctuate and moving the workpiece W side independently in the X, Y, and θ directions as desired, a desired scale pattern or slit pattern is drawn, Engrave.

  The arithmetic processing unit 720 includes a laser / work control numerical arithmetic unit 721 and CAD data (database) 722. The laser / work control numerical calculation device 721 appropriately controls the laser device 716 and the work set / control stage (X table 711, Y table 712, θ table 713). This control mode is controlled based on CAD data (for example, AutoCAD (registered trademark)) 722.

  The visual recognition device 730 includes a camera 731 with a built-in CCD, a half mirror 732, and a light source 733. Light from the light source 733 is reflected by the half mirror 732 to illuminate the workpiece W from directly above. Reflected light from the work W passes through the half mirror 732 and is taken into the camera 731, information corresponding to the positional relationship between the work W and the laser beam is acquired, and this information is sent to the laser / work control numerical calculation device 721. Is fed back.

  As described above, the workpiece W (the rotary plate 1 or the light shielding plate 8) mounted on the workpiece set / control stage is moved to the desired scale by appropriately moving the workpiece set / control stage while fixing the laser beam side. Processing is performed corresponding to the pattern or slit pattern, whereby a scale is cut on the rotating plate and a slit is cut on the light shielding plate.

  Next, FIG. 11 shows a flowchart showing a control program of the arithmetic unit of the laser processing system for the optical rotary encoder of the present invention. This control program is executed by the laser work control numerical operation device 721.

  First, when a setting operation for determining specifications such as the outer shape and resolution of the rotating plate is performed (step 116), calculation of processing start / end positions for one scale pattern or one slit pattern (step 117), θ feed Pitch calculation (step 118) and Z-phase pattern machining start / end point position calculation (step 119) are performed. Thereafter, the workpiece W before slit formation is set on a jig (not shown) on the stage (step 111), and when a start operation is performed (step 112), moving processing to an image recognition position (step 113), origin search After the processing (step 114) and the origin coordinate deviation acquisition processing (step 115) are executed, the specified position of the workpiece is moved to the machining XY-θ coordinates (step 120). Thereafter, after the laser beam is stabilized (steps 121 and 122), the shutter of the laser device is opened (step 123), the laser is emitted (step 124), and laser processing is executed (step). 125). In this laser processing execution process (step 125), as described above, the operation of the XY-θ stage is appropriately performed based on the CAD data 722 (step 126). After that, the shutter is closed (step 127), and it is confirmed whether or not the slit processing is completed (step 128), and if there is any remaining processing, after moving to the next processing position (step 128). 129) The above processing is repeated, and the processing is completed (step 128) after the processing is completed (step 128 is completed).

  As described above, since the processing of the scales and slits on the rotary plate 1 and the light shielding plate 8 of the optical rotary encoder of the present invention is automatically performed through the laser processing system 700, the conventional punching processing technology and photo etching technology are used. Compared to the case of using, there is no need for mold design and mask design and production, so the period from order receipt to processing completion can be shortened remarkably, and the cost is significantly higher than when designing and producing them. You can go down. Therefore, in the optical rotary encoder of the present invention, it is possible to easily cope with so-called high-mix low-volume production and realize this at a low cost.

  In addition, in the optical rotary encoder of the present invention, the processing accuracy of the individual scale elements is improved as much as possible by devising the control of the X table 711, the Y table 712, and the θ table 713. You can also.

  FIG. 12 is a diagram showing individual scale shapes on the rotary plate of the optical rotary encoder of the present invention. The scale element 161 shown in FIG. 4A has a fan shape. This is the same as the scale shape in the case of using a conventional punching forming technique or a photo etching technique. In this case, for example, by moving all of the X table 711, the Y table 712, and the θ table 713 together, the fan-shaped scale element 161 is completed while irradiating the laser as shown by the zigzag locus in the figure. To do.

  The scale element 162 shown in FIG. 4B is a scale element having a novel shape developed by the present inventors. The scale element is entirely surrounded by a straight line, and has a significant difference from the conventional fan-shaped scale. This is based on the premise that the laser processing system shown in FIG. 10 is adopted, so that a highly accurate scale element can be formed by the simplest possible control of the X, Y, and θ tables. That is, in processing the trapezoidal scale element 162, the θ table 713 only needs to be intermittently fed, and when the θ table is stationary, the X table X is shown as a zigzag locus in the figure. By moving the table 711 and the Y table 712 in conjunction with each other at the same time, the inside of the trapezoidal outline can be precisely and easily processed. By adopting such a trapezoidal scale, it is possible to improve the positioning accuracy of the scale compared to the case of using the conventional punching technology and photoetching technology, and it is easy to use the conventional fan shape in a short time. A scale that has almost the same function as the scale can be formed.

  Next, an optical linear encoder that is a second embodiment of the present invention will be described. The appearance of the optical linear encoder according to the present invention is shown in FIG. FIG. 4A shows the appearance of the reflective linear encoder 2000a, and FIG. 4B shows the appearance of the transmissive linear encoder.

  As shown in FIG. 13, the optical linear encoder according to the present invention has a linear scale 21 (a reflective linear scale 21 a or a transmissive linear scale 21 b) engraved with a scale, and an inscribed linear scale 21. An optical reader (optical module) 300 (a reflective optical reader 300a or a transmissive optical reader 300b) for reading the scale is provided.

  Next, FIG. 14 shows the detailed configuration of the reflective optical linear encoder according to the present invention, and FIG. 15 shows the detailed configuration of the transmission optical linear encoder according to the present invention.

As shown in FIG. 14, the reflective optical linear encoder according to the present invention has a linear scale 21a attached to the detection target 22a.
When the light projecting circuit 23 is activated, the light projecting element 24 is driven. The light beam L31 emitted from the light projecting element 24 is transmitted through the half mirror 25 while maintaining a constant spread angle, is converted into parallel light by the lens 26, and is irradiated onto the surface of the linear scale 21a. The light reflected by the surface of the linear scale 21 a passes through the lens 26, is reflected by the half mirror 25, and travels toward the light receiving element 28. On the front side of the light receiving element 28, a light shielding plate 27 provided with a slit to be described later is disposed. The light beam L32 reflected by the half mirror 25 enters the light receiving element 28 through the slit of the light shielding plate 27. The electrical signal generated by the light receiving element 28 is amplified and waveform shaped by the light receiving circuit 29 and then sent to the signal processing unit 30. The signal processing unit 30 generates and outputs a pulse train corresponding to a linear resolution in the case of an incremental type linear encoder, and generates a code signal corresponding to each position in the case of an absolute type linear encoder. Thus, the signal obtained from the signal processing unit 30 is sent to the outside through the output circuit 31. The above is the basic configuration and operation of the reflective optical linear encoder.

  FIG. 15 shows a configuration diagram of a transmission optical linear encoder according to the present invention. The configuration and operation of the transmissive optical linear encoder are basically the same as those of the reflective optical linear encoder shown in FIG. Only the differences will be described. In the figure, the same components as those in FIG.

  The transmissive linear scale 21b has a structure that transmits light corresponding to the scale portion. The light beam L41 emitted from the light projecting element 24 is irradiated onto the lens 26 while maintaining a certain spread angle, and is converted into parallel light L42. Thereafter, the light beam L42 passes through the linear scale 21b and travels toward the light receiving element 28 provided on the opposite side of the light projecting element 24 with the linear scale 21b interposed therebetween. On the front side of the light receiving element 28, a light shielding plate 27 provided with a slit to be described later is disposed. When the light receiving element 28 is irradiated with the light beam L42 after passing through the light shielding plate 27, a corresponding electrical signal is sent out from the light receiving element 28. This electric signal is sent to the outside through the light receiving circuit 29, the signal processing unit 30, and the output circuit 31, as described above with reference to FIG. The above is the basic configuration and operation of the transmission optical linear encoder.

  In the optical linear encoder of the present invention, in the above configuration, the linear scales 21a and 21b and the light shielding plate 27 are devised. More specifically, the linear scales 21a and 21b and the light shielding plate 27 are manufactured using a laser processing machine. FIG. 16 shows a front view of an example of a reflective or transmissive incremental linear scale.

  As shown in the figure, the linear scale 21 is formed in a rectangular shape, and a scale row band 40 is provided on the surface thereof.

  An enlarged view of a portion B in FIG. 16 is shown in FIG. As shown in the figure, the scale row band 40 is composed of three scale rows including a first scale row 40a, a second scale row 40b, and a third scale row 40c. As will be described later, these scale rows are formed using a laser processing machine. That is, the scale is engraved by laser irradiation rather than by punching or photoetching as in the conventional linear scale. The second scale row 40b is an A-phase pattern and a B-phase pattern for outputting a pulse train as an incremental linear encoder and detecting the moving direction of the linear scale 21. The first scale row 40a and the third scale row 40c are Z-phase patterns for detecting the origin position.

  On the other hand, an example of the light shielding plate 27 of the optical linear encoder of the present invention is shown in FIGS. In these drawings, reference numeral 27 is a light shielding plate, 271 and 272 are positioning holes for attaching the light shielding plate to a laser processing machine to be described later, 273 is a thick region, 274 is a thin region, and 275 is a thick region and a thin wall. A boundary line with the region, 276a is a first slit row, 276b is a second slit row, 276c is a third slit row, and 276d is a fourth slit row.

  The structure of the light shielding plate of the optical linear encoder of the present invention and the manufacturing process for engraving the scale will be described in detail later, but only the slit arrangement on the light shielding plate will be described here. The arrangement of the slit rows is irrelevant to the cross-sectional structure and material of the light shielding plate, and is common to the light shielding plates of any optical linear encoder.

  That is, as shown in FIG. 19, four slit rows including a first slit row 276a, a second slit row 276b, a third slit row 276c, and a fourth slit row 276d are formed in the central portion of the light shielding plate. Has been. Each of the slits constituting the slit row is a through hole or a transparent hole, and light can pass through only the slit portion. These slit rows have a certain relationship with the scale rows of the linear scale 21 shown in FIGS.

  Next, FIG. 21 shows an explanatory diagram of a method for processing the linear scale and the light shielding plate of the optical linear encoder of the present invention. 2A and 2B show the cross-sectional structure of the linear scale 21, and FIG. 2C and FIG. 2D show the cross-sectional structure of the light shielding plate 27.

  First, the cross-sectional structure (part 1) of the linear scale shown in FIG. The linear scale shown in this example can be applied to a reflective optical linear encoder. In this linear scale, the metal substrate 200 having a mirror surface is selectively irradiated with a laser beam to be roughened, thereby forming a regular reflection portion and an irregular reflection portion. For example, stainless steel (SUS) is used as the metal substrate 200, and the thickness d1 is about 100 μm. In the figure, reference numeral 200a is a mirror surface area, and reference numeral 200b is a rough surface area. The mirror surface area 200a is the original surface of the metal substrate 200 exposed as it is, and the rough surface area 200b is a portion roughened by laser irradiation. According to such a configuration, the light beam L1 irradiated from the light projecting element to the rough surface area 200b is scattered and hardly returns to the light receiving element, whereas the light beam irradiated from the light projecting element to the mirror surface area 200a. L2 is regularly reflected and most of the light returns to the light receiving element. The mirror surface area 100a corresponds to the scale area a in the enlarged view of the portion A in FIG. On the other hand, the rough surface area 200b corresponds to the peripheral area b in the enlarged view of the B part in FIG. Therefore, the surface of the linear scale is irradiated with light from the light projecting element, and the reflected light is photoelectrically converted to correspond to the first scale row 40a, the second scale row 40b, and the third scale row 40c. An electrical signal can be acquired.

  Next, the cross-sectional structure (part 2) of the linear scale shown in FIG. The linear scale shown in this example can be applied to both a reflection type and a transmission type. This linear scale has a transparent substrate 210 and a metal thin film 220 deposited on the surface thereof. As a material of the transparent substrate 210, glass, plastic, or the like can be used. On the other hand, as a material of the metal thin film 220, a highly reflective metal material such as chromium (Cr) can be employed. In this example, a rectangular material having a metal thin film (chromium vapor deposition film) 220 deposited on the surface of a transparent substrate (glass plate) 210 is prepared, and the surface is selectively irradiated with a laser beam. Thus, the metal thin film 220 is selectively removed (sublimation removed) to form the thin film removal region 220a. According to such a configuration, the light beam L3 irradiated from the light projecting element to the mirror surface (the region where the thin film is not removed) of the metal thin film 220 is regularly reflected and returned to the light receiving element. The light beam L4 irradiated to the removal region 220a passes through the transparent substrate 210 and passes through, and is hardly returned to the light receiving element. When this linear scale is used as a reflection type, the mirror surface of the metal thin film 220 is a scale area a in the enlarged view of the B part in FIG. On the other hand, the thin film removal region 220a is a peripheral region b in the enlarged view of the B part in FIG. On the other hand, when this linear scale is used as a transmission type, the thin film removal region 220a is a scale region a in the enlarged view of the B part in FIG. 17, and the mirror surface of the metal thin film 220 is conversely a peripheral region b. When a glass plate is used as the transparent substrate 220, it is preferable to adopt B270 when the reflective type is used, and BK-7 when the transmissive type is used. Since BK-7 has a high transmittance, BK-7 is superior in the transmission type. On the other hand, in the case of a reflective type that does not require consideration of the transmittance, it is preferable to adopt B270 having a low cost. When glass is used as the transparent substrate 210, the thickness d2 is about 1.1 mm. On the other hand, when a chromium deposition film is used as the metal thin film 220, the thickness d3 of the chromium deposition film is about 1400 mm. It is said.

  Next, a cross-sectional structure (No. 1) of the light shielding plate of the optical linear encoder shown in FIG. In this example, the light shielding plate is mainly composed of a thin metal plate 230. On the surface of the thin metal plate 230, an electroformed metal layer 240 is grown while leaving a thin region 250 to be laser processed. For example, nickel (Ni) is used as the material of the metal thin plate 230, and similar nickel (Ni) is used as the electroformed metal layer 240. The thickness d4 of the thin region 250 is about 0.01 mm, and the thickness d5 of the electroformed metal layer 240 is about 0.04 mm. Therefore, the total thickness of the thick portion is about 0.05 mm.

  The example shown in FIG. 21C corresponds to the light shielding plate 27 of the optical linear encoder shown in FIGS. That is, in this example, the thin region 274 surrounded by the boundary line 275 in the rectangle shown in FIG. 18 becomes the thin region 250, and the thick region 273 in the peripheral portion is formed by the electroformed metal layer 240 being grown. Prepare a shading plate that will be the area.

  This light shielding plate is fixed via positioning holes 271 and 272 on the stage of a laser processing machine of an optical linear encoder which will be described in detail later. Thereafter, by irradiating the laser beam into the thin region 274, as shown in FIG. 19, the first slit row 276a, the second slit row 276b, the third slit row 276c, and the fourth slit row 276d are shown. As described above, the slit rows are formed through the laser beam. As shown in FIG. 21C, the portion irradiated with the laser beam becomes a perforated region 230a, whereas the metal thin plate 230 remains as it is in the portion not irradiated with the laser beam. Here, the perforated region 230a corresponds to the slit region c in the enlarged view of FIG. On the other hand, the surface of the thin metal plate 230 having light shielding properties corresponds to the peripheral region d in the enlarged view of FIG. As is clear from FIG. 21 (c), the light beam L5 irradiated to the perforated region 230a escapes to the opposite side, whereas the light beam L6 irradiated to the metal thin plate 230 is reflected and returned.

  Next, a cross-sectional structure (No. 2) of the light shielding plate of the optical linear encoder shown in FIG. In this example, a transparent substrate (glass or plastic) 211 and a metal thin film (such as a chromium deposition film) 221 deposited on the transparent substrate 211 are provided. Then, by removing the metal thin film 221 by selective irradiation with a laser beam, the light shielding plate 27 is manufactured by forming the thin film removal region 221a. When a glass plate is used as the transparent substrate 211, the thickness d6 is about 0.5 to 1.2 mm, and when a chromium vapor deposition film is used as the metal thin film 221, the thickness d7 completely absorbs light. It is set to about 1400 mm so that it can be shut off. Here, the region where the metal thin film 221 is deposited corresponds to the peripheral region d in the enlarged view of FIG. 20, and the thin film removal region 221a corresponds to the slit region c.

  Next, FIG. 22 shows a configuration diagram of the laser processing system of the optical linear encoder of the present invention. As shown in the figure, the laser processing system 800 includes a laser processing device 810, an arithmetic processing device 820, and a visual recognition device 830.

  The laser processing apparatus 810 has a work set / control stage for positioning the work W. This control stage has an X table 811 responsible for movement in the X direction, a Y table 812 responsible for movement in the Y direction, and a feed responsible for the dimension feed operation (feeding operation) of the plate-like workpiece W wound in a roll shape. And a jig 813-813. Then, the workpiece W is fed out by a predetermined amount onto the Y table 812 by a feeding jig 813-813. In the present invention, the workpiece W is the linear scale 21 or the light shielding plate 27.

  The laser device 816 includes a power supply device 817 and a cooling device 818, and is configured by a YAG laser (in this example, second harmonic: 532 nm, output: about 0.5 mJ, repetition frequency: 5 to 40 kHz). The laser beam emitted from the laser device 816 is reflected by the mirror 815, condensed through the condenser lens 814, and then irradiated onto the surface of the workpiece W. Particularly in this example, in order to enable precise machining, the galvano mirror included in a normal laser processing machine of this type is fixed, and all beam operations on the workpiece W are borne by the control stage side. It has become so. That is, by fixing the laser beam so that it does not fluctuate and moving the workpiece W side independently in the X direction, Y direction, and feeding direction as appropriate, a desired scale pattern or slit pattern is drawn, Engrave.

  The arithmetic processing unit 820 includes a laser work control numerical value arithmetic unit 821 and CAD data (database) 822. The laser / work control numerical calculation device 821 appropriately controls the laser device 816 and the work set / control stage (X table 811, Y table 812, feed jig 813-813). This control mode is controlled based on CAD data (for example, AutoCAD (registered trademark)) 822.

  The visual recognition device 830 includes a camera 831 with a built-in CCD, a half mirror 832, and a light source 833. Light from the light source 833 is reflected by the half mirror 832 to illuminate the workpiece W from directly above. Reflected light from the work W passes through the half mirror 832 and is taken into the camera 831, information corresponding to the positional relationship between the work W and the laser beam is acquired, and this information is sent to the laser / work control numerical calculation device 821. Is fed back.

  As described above, the workpiece W (linear scale 21 or light shielding plate 27) mounted on the workpiece set / control stage is moved to the desired scale by appropriately moving the workpiece set / control stage while fixing the laser beam side. It is processed according to the pattern or slit pattern, whereby a scale is engraved on the linear scale and a slit is engraved on the light shielding plate.

  Next, FIG. 23 shows a flowchart showing a control program of the arithmetic unit of the laser processing system of the optical linear encoder of the present invention. This control program is executed by the laser / work control numerical calculation device 821.

  First, when a setting operation for determining specifications such as the length and resolution of the linear scale is performed (step 236), the calculation start / end positions for one scale pattern or one slit pattern are calculated (step 237), the workpiece Processing of feed pitch calculation (step 238) and Z-phase pattern processing start / end position calculation (step 239) is performed. Thereafter, the workpiece W before slit processing is set on a jig on the stage (step 231), and when a start operation is performed (step 232), the movement process to the image recognition position (step 233), the origin search process ( After the step 234) and the origin coordinate deviation acquisition process (step 235) are executed, the specified position of the workpiece is moved to the machining XY coordinate (step 240). Thereafter, after the laser beam is stabilized (steps 241 and 242), the shutter of the laser device is opened (step 243), the laser is emitted (step 244), and laser processing is executed (step). 245). In the laser processing execution process (step 245), as described above, the XY stage and the feeding jig are appropriately operated based on the CAD data 822 (step 246). After that, the shutter is closed (step 247), and it is confirmed whether or not the slit processing is completed (step 248), and if there is any remaining processing, the moving processing to the next processing position is performed (step 248). 249) The above processing is repeated, and the processing is completed (step 248 is completed), and the processing end processing is performed (step 250).

  As described above, since the scales and slits for the linear scale 21 and the light shielding plate 27 of the optical linear encoder of the present invention are automatically processed through the laser processing system 800, the conventional punching technology and photoetching technology are used. Compared to the case of using, there is no need for mold design and mask design and production, so the period from order receipt to processing completion can be shortened remarkably, and the cost is significantly higher than when designing and producing them. You can go down. Therefore, in the optical linear encoder of the present invention, it is possible to easily cope with so-called high-mix low-volume production and realize this at a low cost.

  In addition, in the optical linear encoder of the present invention, the processing accuracy of the individual scale elements is made as much as possible by devising the control of the X table 811, the Y table 812, and the feed jig 813-813. It can also be improved.

  In the above description, the linear scale 21 of the optical linear encoder is attached to the object 22 to be detected. However, the linear scale may be directly engraved on the surface of the object 22 to be detected by laser processing. Is possible.

It is an external view of a reflection type optical rotary encoder. It is a block diagram of a reflection type optical rotary encoder. It is a block diagram of a transmission type optical rotary encoder. It is a front view of the rotating plate of an optical rotary encoder. It is the A section enlarged view in FIG. It is explanatory drawing (before laser processing) of the light-shielding plate of an optical rotary encoder. It is explanatory drawing (after laser processing) of the light-shielding plate of an optical rotary encoder. It is an enlarged view of the slit row | line | column on the light-shielding plate of an optical rotary encoder. It is explanatory drawing of the processing method of the rotating plate and light-shielding plate of an optical rotary encoder. It is a block diagram of the laser processing system of an optical rotary encoder. It is a flowchart which shows the control program of the arithmetic unit in the laser processing system of an optical rotary encoder. It is a figure which shows each scale shape on the rotating plate of an optical rotary encoder. It is an external view of a reflective optical linear encoder. It is a block diagram of a reflection type optical linear encoder. It is a block diagram of a transmissive | pervious optical linear encoder. It is a front view of the linear scale of an optical linear encoder. It is the B section enlarged view in FIG. It is explanatory drawing (before laser processing) of the light-shielding plate of an optical linear encoder. It is explanatory drawing (after laser processing) of the light-shielding plate of an optical linear encoder. It is an enlarged view of the slit row | line | column on the light-shielding plate of an optical linear encoder. It is explanatory drawing of the processing method of the linear scale of an optical linear encoder, and a light-shielding plate. It is a block diagram of the laser processing system of an optical linear encoder. It is a flowchart which shows the control program of the arithmetic unit in the laser processing system of an optical linear encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating plate 1a Reflective rotating plate 1b Transmission type rotating plate 2 Shaft 3 Bearing 4 Light emitting circuit 5 Light emitting element 6 Half mirror 7 Lens 8 Light shielding plate 9 Light receiving element 10 Light receiving circuit 11 Signal processing unit 12 Output circuit 13 Scale row DESCRIPTION OF SYMBOLS 12 Output circuit 13a 1st scale row 13b 2nd scale row 13c 3rd scale row 14 Shaft hole 21 Linear scale 21a Reflection type linear scale 21b Transmission type linear scale 22 Object to be detected 23 Emitting circuit 24 Emitting element 25 half mirror 26 lens 27 light shielding plate 28 light receiving element 29 light receiving circuit 30 signal processing unit 31 output circuit 40 graduation band 40a first graduation line 40b second graduation line 40c third graduation line 51 mounting base 52 optical type Reader 53 Substrate 81 Positioning hole 82 Positioning hole 83 Thick region 84 Thin region 8 Boundary line 86a First slit row 86b Second slit row 86c Third slit row 86d Fourth slit row 100 Metal substrate 100a Mirror surface region 100b Rough surface region 110 Transparent substrate 111 Transparent substrate 120 Metal thin film 121 Metal thin film 121a Thin film removal region 130 Metal Thin plate 130a Perforated 140 Electroformed metal layer 150 Thin area 161 Fan-shaped scale element 162 Trapezoidal scale element 200 Metal substrate 200a Mirror surface area 200b Rough surface area 210 Transparent substrate 211 Transparent substrate 220 Metal thin film 221 Metal thin film 221a Thin film removal area 230 Thin metal plate 230a Perforated 240 Electroformed metal layer 250 Thin region 271 Positioning hole 272 Positioning hole 273 Thick region 274 Thin region 275 Boundary line 276a First slit row 276b Second slit row 276c 3 slit row 276d 4th slit row 300 optical reader 700 laser processing system 710 laser processing device 711 X table 712 Y table 713 θ table 714 condenser lens 715 mirror 716 laser device 717 power supply device 718 cooling device 720 arithmetic processing device 721 Laser work numerical calculation device 722 CAD data 730 Visual recognition device 731 Camera 732 Half mirror 733 Light source 800 Laser processing system 810 Laser processing device 811 X table 812 Y table 813 Feed jig 814 Condensing lens 815 Mirror 816 Laser device 817 Power supply device 818 Cooling device 820 Arithmetic processing device 821 Laser work numerical operation device 822 CAD data 830 Visual recognition device 831 Camera 832 Half mirror 833 light source 1000 optical rotary encoder (without outer shell case)
2000 Optical linear encoder a Scale area b Peripheral area c Slit area d Peripheral area W Workpiece

Claims (16)

A rotary plate engraved with a scale along a circle, an optical reader that includes a light projecting element, a lens, a light-shielding plate, and a light-receiving element, reads the scale from the rotary plate, and is arranged on the front surface of the optical reader and is a rotary plate An optical rotary encoder that has a light-shielding plate with a slit corresponding to the upper scale, and reads the scale engraved on the rotating plate by collimating the light from the light projecting element with a lens and irradiating the rotating plate Because
An optical rotary encoder characterized in that the scale on the rotating plate is carved by laser irradiation. The optical rotary encoder according to claim 1, wherein the slit on the light shielding plate is also engraved by laser irradiation. 3. The optical rotary encoder according to claim 1, wherein the rotary plate is read by a reflection type. 4. The optical rotary encoder according to claim 1, wherein the scale shape on the rotating plate is a trapezoidal shape. A rotary plate for an optical rotary encoder that is graduated along a circle by laser irradiation. 6. The rotating plate for an optical rotary encoder according to claim 5, wherein the reading method is a reflection type. The rotary plate for an optical rotary encoder according to claim 5 or 6, wherein the scale has a trapezoidal shape. A light shielding plate for an optical rotary encoder with slit rows carved by laser irradiation. In the state where the rotating plate material is set on the XYθ table of the laser processing apparatus, the movement of the XYθ table is appropriately controlled while irradiating this with the laser beam, and the scale is engraved along the circle on the rotating plate material. A method for manufacturing a rotary plate for an optical rotary encoder. A laser beam irradiation coordinate is calculated based on the required outer shape and resolution of the rotating plate, and a scale plate having an arbitrary specification is manufactured by controlling the movement of the XYθ table based on the calculated coordinate. The manufacturing method of the rotary plate for optical rotary encoders of Claim 9. 10. The method for manufacturing a rotary plate for an optical rotary encoder according to claim 9, wherein only the XYθ table is controlled to move while the optical axis deflection angle of the laser beam is fixed. 11. The trapezoidal scale is carved along a circle on the rotating plate material by intermittently rotating the θ table while continuously moving the XY table. A method of manufacturing a rotary plate for an optical rotary encoder. 12. The rotating plate material is a metal plate in which only a laser processing region is a thin region, and a through hole is formed by selectively irradiating a laser beam on the metal plate. Of manufacturing a rotary plate for an optical rotary encoder. The rotating plate material is a transparent substrate having a highly reflective or light-shielding metal coating on the surface, and a transparent hole is formed by selectively irradiating a laser beam on the substrate to remove the metal coating. A method for manufacturing a rotary plate for an optical rotary encoder according to any one of claims 9 to 11. 12. The optical rotary according to claim 9, wherein the rotating plate material is a metal plate having a mirror surface, and a laser beam is selectively irradiated to form a rough surface region. A method of manufacturing a rotary plate for an encoder. In the state where the light shielding plate material is set on the XYθ table of the laser processing apparatus, the movement of the XYθ table is appropriately controlled while irradiating the laser beam to this, and a through slit or a transparent slit row is engraved on the light shielding plate material. A method of manufacturing a light shielding plate for an optical rotary encoder.

Images