JP5266561B2 - Optical encoder and scale plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical encoder having a smaller number of components which can furthermore improve assembly accuracy to reduce dimension dispersion between each component or the like, and to provide a scale plate constituting the optical encoder. <P>SOLUTION: The optical encoder 100 includes the scale plate 2 installed on a member 10 for displacement control, a light emitting source 1 for supplying light with which the scale plate 2 is irradiated, and a light receiving element 4 for detecting light with which the scale plate 2 is irradiated. On the scale plate 2, a signal track 3 including a reflecting material for changing the quantity of light entering the light receiving element 4 by reflecting the light is arranged. On the signal track 3, the reflecting material is printed periodically in a direction along a displacement direction of the member 10 for displacement control. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an optical encoder and a scale plate, and more particularly to an optical encoder that detects the amount of movement and rotation of a member, and a scale plate that constitutes the optical encoder.

  The optical encoder detects, for example, the amount of movement, rotation, position, and direction of movement (rotation) of a movable member that constitutes a machining facility with high accuracy, and the detected information is accurately transmitted to the drive unit of the facility. This is a device used for feedback.

  The optical encoder is configured such that the illuminance when the light from the light emitting source is detected by the light receiving unit changes regularly according to the amount of movement of the movable member (displacement control member). The amount of movement is detected. This is the same when the displacement control member moves linearly and when the displacement control member rotates.

  Here, it is more preferable that the illuminance distribution of the light received at the light receiving unit of the optical encoder is a sine wave with less distortion. Therefore, conventionally, for example, an optical encoder disclosed in Japanese Patent Laid-Open No. 5-87592 (Patent Document 1) has the following configuration. The optical encoder includes a light emitting source, a diffusion plate, a mask, a code plate, and a light receiving array. The diffusion plate has a role of outputting light from the light source as diffused light. The mask has a shape in which the contour of the window portion through which light from the diffuser plate passes is a shape obtained by folding a sine wave having a plurality of pitches up and down, or a shape approximating a waveform similar to a sine wave. In the code plate (scale plate), slit portions and light shielding portions that allow light that has passed through the window portion of the mask to pass through are alternately arranged. The light receiving array receives light that has passed through the code plate.

  By providing the mask with a sinusoidal window, the illuminance distribution of light passing through the window becomes sinusoidal. When the illuminance distribution of the light received at the light receiving unit changes to draw a sine wave due to a change in the moving amount (or rotation angle) of the movable member, for example, the illuminance distribution of the light changes to draw a rectangular wave. Compared to the case, information on the movement amount (rotation angle) can be detected with higher accuracy. This is because a sine wave is a function whose value continuously changes with respect to an independent variable (here, a movement amount or a rotation angle) unlike a rectangular wave.

JP-A-5-87592

  In the optical encoder disclosed in Japanese Patent Laid-Open No. 5-87592, the illuminance distribution of light received by the light receiving array forms a sine wave with respect to the amount of movement of the code plate. A window portion as a through hole having a complicated (sinusoidal) shape is formed. Further, the optical encoder disclosed in Japanese Patent Laid-Open No. 5-87592 includes a light emitting source, a diffusion plate, a mask, a code plate, and a light receiving array unit, and thus the number of components provided in the apparatus is large. For this reason, there exists a problem that manufacture of an optical encoder is complicated.

  Further, these parts having a large number of points need to be assembled with high accuracy so that, for example, a variation in dimensions between parts is reduced among a plurality of optical encoders. For this reason, the problem that manufacture of the said optical encoder is difficult arises.

  The present invention has been made in view of the above problems. An object of the present invention is to provide an optical encoder that can improve assembly accuracy by reducing the number of parts and reducing variations in dimensions between parts. Moreover, it is providing the scale board which comprises the said optical encoder.

An optical encoder according to one aspect of the present invention includes a scale plate installed on a displacement control member, a light emission source that supplies light to be applied to the scale plate, and a light receiving element that detects light applied to the scale plate. And an optical encoder. The scale plate is provided with a signal track including a reflective material for reflecting light and changing the amount of light incident on the light receiving element. In the signal track, the reflector is periodically printed in the direction along the displacement direction of the displacement control member. The signal track includes a reflective portion including a reflective material and a non-reflective portion where no reflective material is disposed. Concave and convex shapes are formed on the main surface of the scale plate. In the signal track, a reflective material for forming a reflective portion is disposed on the convex portion of the uneven shape of the scale plate.

An optical encoder according to another aspect of the present invention includes a scale plate installed on a member for displacement control, a light source that supplies light to be applied to the scale plate, and a light receiving element that detects light applied to the scale plate. And an optical encoder. The scale plate is provided with a signal track including an absorber for absorbing or shielding light and changing the amount of light incident on the light receiving element. In the signal track, the absorbent material is periodically printed in the direction along the displacement direction of the displacement control member. Concave and convex shapes are formed on the main surface of the scale plate.

  In the present invention, a reflecting material or an absorbing material is printed on a signal track of a scale plate that controls the amount of supply of light from the light source to the light receiving element. Since reflection material and absorption material are applied and formed by printing, for example, compared to the case where a through-hole having a sinusoidal shape is formed in the mask or the slit portion is formed in the scale plate, the scale plate and the optical encoder The manufacturing cost can be reduced.

1 is a schematic diagram illustrating a configuration of an optical encoder according to a first embodiment. It is a top view which shows the aspect of the signal track | truck used for the optical encoder of this Embodiment 1. FIG. It is the upper side figure which took out one of the reflective parts arranged in a plurality of periods in a signal track. It is the schematic which shows the structure of the optical encoder of this Embodiment 2. FIG. 5 is a schematic diagram illustrating a configuration different from that of FIG. 4 of the optical encoder according to the second embodiment. It is the schematic which shows the structure of the optical encoder of this Embodiment 3. It is the schematic which shows the structure of the optical encoder of this Embodiment 4. In the optical encoder of Embodiment 5, it is the top view which took out one of the reflective parts arranged in multiple periods in a signal track. It is a top view which shows the aspect of the reflecting material printed on the signal track of the optical encoder of this Embodiment 7. It is a top view which shows the aspect of the reflecting material printed on the signal track of the optical encoder of this Embodiment 8. It is a schematic sectional drawing in the part which follows the XI-XI line of FIG. It is a top view which shows the aspect of the reflecting material printed on the signal track of the optical encoder of this Embodiment 9. It is a schematic sectional drawing in the part which follows the XIII-XIII line | wire of FIG. It is a top view which shows the aspect of the reflecting material printed on the signal track of the optical encoder of this Embodiment 10. It is a schematic sectional drawing in the part which follows the XV-XV line | wire of FIG. It is a schematic sectional drawing which shows the process in which the signal track | truck of the optical encoder of this Embodiment 10 is formed. It is a schematic sectional drawing which shows the state in which the signal track | truck of the optical encoder of this Embodiment 10 was formed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each embodiment, elements having the same function are denoted by the same reference numerals, and the description thereof will not be repeated unless particularly necessary.

(Embodiment 1)
Referring to FIG. 1, an optical encoder 100 according to the present embodiment is an apparatus used to detect information such as a moving amount, a moving direction, and a position of a displacement control member that moves linearly. The optical encoder 100 includes a light emitting source 1, a scale plate 2, and a light receiving element 4. A signal track 3 is disposed on the surface of the scale plate 2.

  The light emitting source 1 is a component that irradiates the scale plate 2 and supplies light received by the light receiving element 4. As the light emitting source 1, for example, a light emitting diode that emits red visible light or infrared light having a wavelength of about 600 nm to about 950 nm is used. Note that a point light source light emitting diode or the like can be used as the light source 1 in order to detect more accurate information by irradiating light to a narrower region of the signal track 3 on the scale plate 2.

  The scale plate 2 has, for example, a long shape, and is disposed so as to be attached to a long-shaped displacement control member 10 that moves in a direction along a straight line, for example. The displacement control member 10 is, for example, a member constituting the machining equipment that moves in a direction along a straight line during machining (not shown in FIG. 1; hereinafter referred to as “linear movement member”). It is arranged to be attached to. The displacement control member 10 is a member for controlling the amount of movement in the direction along the straight line of the linear direction moving member, for example. In addition, you may attach the scale board 2 directly to the said member which comprises the equipment for machining.

  The scale plate 2 is preferably made of a material that does not reflect the light emitted from the light source 1. Here, not reflecting light means that the reflectance of light emitted from the light emitting source 1 is less than 5%.

  Specifically, the scale plate 2 is preferably made of a black material that absorbs light, for example. Here, “absorbing light” means that the absorption rate of light emitted from the light emitting source 1 is 90% or more. As the black material satisfying this condition, it is preferable to use, for example, a resin such as a thermoplastic resin, a thermosetting resin, or a photocurable resin. Or it is good also as a structure which formed the main body of the scale board 2 with the metal material or the glass material, and coat | covered the surface with the black-type material (resin) mentioned above.

  Alternatively, the scale plate 2 may be made of a material that transmits light emitted from the light source 1, for example. Here, “transmitting light” means that the transmittance of light emitted from the light emitting source 1 is 90% or more. Here, it is preferable to use, for example, a transparent resin or glass as a material that transmits light.

  The signal track 3 is an area where ink 5 as a reflecting material for reflecting the light emitted from the light source 1 and supplying it to the light receiving element 4 is disposed. The signal track 3 has a certain width in the vicinity of the center in the width direction (for example, the vertical direction in FIG. 2) intersecting the direction in which the scale plate 2 extends, and extends in the direction in which the scale plate 2 extends. The region is formed by printing. The signal track 3 reflects the light emitted from the light source 1 (including the ink 5 as a reflective material) and does not reflect the light emitted from the light source 1 (the ink 5 as a reflective material is not disposed). ) The non-reflective portion 3b. A plurality of reflecting portions 3 a and non-reflecting portions 3 b are arranged at regular intervals in the extending direction of the scale plate 2.

Here, reflecting light means that the reflectance of light is 80% or more.
The light receiving element 4 receives the light reflected by the signal track 3 among the light irradiated on the scale plate 2 and converts the received light into an electric signal by photoelectric conversion. The light receiving element 4 is an element for detecting the illuminance of the received light by detecting the electrical signal. As the light receiving element 4, for example, a sensor photodiode is used. If a sensor photodiode is used, information can be detected with higher accuracy.

  The ink 5 is arranged by being printed on the upper surface of the reflecting portion 3a. That is, here, the ink 5 is formed of a material having a property of reflecting light emitted from the light emitting source 1.

  Specifically, the ink 5 is preferably made of a material in which, for example, silver (Ag) metal powder is filled in the ink 5. Alternatively, instead of silver, the ink 5 may be made of a material filled with metal powder such as gold (Au), aluminum (Al), or chromium (Cr).

  As shown in FIG. 2, the ink 5 is printed on the upper surface of the reflecting portion 3 a so as to be periodically different for each predetermined length in the extending direction of the scale plate 2. For example, the density at which the ink 5 is printed at a certain length in the extending direction of the scale plate 2 (the amount of ink 5 printed per unit area, for example, the area where the ink 5 is printed per unit area) (Area) may change periodically. Alternatively, at a certain length in the direction in which the scale plate 2 extends, the concentration of, for example, silver metal powder filled in the ink 5 to be printed (in the unit volume of the ink 5, for example, silver metal powder) It may be printed so that the amount of the substance) is periodically changed. As described above, in the reflecting portion 3a, the density of the reflecting material, which is the first ink containing the metal powder that reflects the light emitted from the light emitting source 1, is changed according to the position of the scale plate 2 in the extending direction. It is a configuration. If it says from a different viewpoint, in the reflection part 3a, the density of a reflection material is the highest in the center part in the direction where the scale board 2 is extended, and the density of a reflection material is falling as it leaves | separates from a center part.

Next, the operation principle of the optical encoder 100 will be described.
In the optical encoder 100, as described above, the displacement control member 10 is disposed so as to be attached to the linear movement member. The scale plate 2 is disposed so as to be attached to the displacement control member 10. That is, the displacement control member 10 and the scale plate 2 move by the same amount in the same direction as the linear movement member.

  If the direction in which the linear direction moving member moves is the left-right direction in FIG. 1, the scale plate 2 and the displacement control member 10 also move in the left-right direction in FIG. That is, the scale plate 2 and the displacement control member 10 move along their extending directions.

  Therefore, if the reflecting portions 3a of the signal track 3 are arranged at regular intervals in the extending direction of the scale plate 2, it can be said that the reflecting portions 3a are arranged at regular intervals along the direction in which the scale plate 2 moves.

  As shown in FIG. 2, the printed density of the ink 5 or the density of the metal powder filled in the ink 5 differs depending on the position of the reflecting portion 3 a, particularly with respect to the extending direction of the scale plate 2. .

  While the scale plate 2 moves along these extending directions together with the linearly moving member, the light source 1 and the light receiving element 4 do not move and are always fixed at the same place in the optical encoder 100. Yes. Accordingly, if the scale plate 2 moves, the position of the scale plate 2 (signal track 3) to which the light beam 1a (see FIG. 1) emitted from the light source 1 is irradiated changes.

  Since the printed density of the ink 5 periodically changes along the direction in which the scale plate 2 extends, if the position of the scale plate 2 to which the light beam 1a is irradiated changes, The ratio at which the light beam 1a is reflected and supplied to the light receiving element 4 changes. This is because the reflectance of the light beam 1a changes according to the density at which the ink 5 is printed and the packing density of the metal powder in the ink 5. Specifically, when the density of the ink 5 or the filling density of the metal powder is increased, the reflectance of the light beam 1a is increased.

  Therefore, by analyzing the amount of light supplied to the light receiving element 4, the position on the scale plate 2 (signal track 3) irradiated with the light beam 1a can be detected. That is, since the movement amount of the scale plate 2 can be known, the movement amounts of the displacement control member 10 and the linear movement member can be known. Then, the displacement control member 10 feeds back information on the amount of movement of the linear movement member to the linear movement member, for example, so that the movement amount of the linear movement member can be controlled with high accuracy.

  Here, the manner in which the density of the ink 5 in the reflecting portion 3a in FIG. 2 changes is as shown in FIG. A configuration in which the density at which the ink 5 is printed (or the filling density of the metal powder in the ink 5) changes continuously and in an inclined manner (for example, to draw a sine wave) at each position in the left-right direction in FIG. It has become. Specifically, the density of the ink is lower at the end of the reflecting portion 3a with respect to the direction in which the scale plate 2 extends (the left-right direction in FIG. 3). It is preferable to change the density so that the density becomes higher at the center.

  As in FIG. 3, the reflection portion 3 a in which the printing density of the ink 5 (or the filling density of the metal powder in the ink 5) changes continuously and in an inclined manner is constant with respect to the extending direction of the scale plate 2. It is preferable that they are regularly arranged for each distance.

  In addition, it is more preferable that the density at which the ink 5 is printed (or the filling density of the metal powder in the ink 5) continuously and greatly changes at each position in the left-right direction in FIG. In this way, the position irradiated with the light beam 1a can be detected with higher accuracy.

  When light emitted from the light source 1 is applied to the non-reflecting portion 3 b where the ink 5 is not printed in the signal track 3, the light is not reflected and is hardly supplied to the light receiving element 4. This is because the surface of the non-reflecting portion 3b is a part of the scale plate 2 made of a material that does not reflect the light emitted from the light emitting source 1. As described above, the signal track 3 includes the reflecting portion 3a that reflects the light emitted from the light emitting source 1 and the non-reflecting portion 3b that does not reflect the light. The distribution of the illuminance supplied to the light receiving element 4 by reflecting the light emitted from can be made clearer. That is, the position irradiated with the light beam 1a can be detected with higher accuracy.

  Also, as described above, the light reflectance is lowered by reducing the ink density at the end of the reflecting portion 3a in the left-right direction that is relatively close to the non-reflecting portion 3b. . For this reason, with respect to the direction in which the scale plate 2 extends, the difference in reflectance is small even at the boundary between the reflecting portion 3a and the non-reflecting portion 3b. In other words, the density (reflectance) at which the ink 5 is printed continuously changes in the extending direction of the scale plate 2 even at the boundary between the reflecting portion 3a and the non-reflecting portion 3b. This also improves the position detection accuracy.

Next, the effect of this Embodiment is demonstrated.
In the present embodiment, the ink 5 for changing the reflectance of light is formed by printing on the signal track 3. For this reason, compared with the case where the through-hole which has a sine wave shape is formed in a mask, the area | region which changes the reflectance of light can be formed easily, for example. Further, since the region where the reflectance of light is changed by printing is formed, the number of parts required for the optical encoder 100 can be further reduced. Since the manufacturing process becomes simple and the number of parts is reduced, the manufacturing cost of the optical encoder 100 can be greatly reduced.

  Further, in the first embodiment, for example, in the optical encoder disclosed in Japanese Patent Laid-Open No. 5-87592, a diffusion plate that outputs light from a light source as diffused light and a through hole having a sine wave shape are formed. No mask is provided.

  Since the number of parts constituting the optical encoder 100 is reduced, it is possible to reduce variation in dimensions such as a gap between parts when the parts constituting the optical encoder 100 are assembled. Therefore, the processing accuracy of the optical encoder 100 can be improved. As a result, the quality of the optical encoder 100 can be stabilized and the reliability can be improved.

(Embodiment 2)
The present embodiment is different from the first embodiment in the area in which light emitted from the light emitting source 1 is reflected. Hereinafter, the configuration of the present embodiment will be described.

  In the optical encoder 100 according to the first embodiment, the scale plate 2 is made of a material that absorbs or transmits light, and the reflection portion 3 a on which the ink 5 that reflects the light is printed is disposed on the signal track 3. On the other hand, in the second embodiment, as in the optical encoder 200 of FIG. 4, for example, the scale plate 2 is made of a material that reflects light, and the scale plate 2 (signal track 3) extends in the extending direction. Ink as an absorbing material that absorbs (shields) light is printed.

  As shown in FIG. 4, in the optical encoder 200, the reflecting portion 3 a constituting the signal track 3 arranged at the same position as the optical encoder 100 is an area where light is reflected by the material constituting the scale plate 2. It is. The non-reflective portion 3b is a region where light is absorbed (shielded) by printing ink that absorbs (shields) light. For example, black ink can be used as the ink that absorbs light.

  In this case, when the light beam 1 a emitted from the light source 1 is applied to the reflection portion 3 a of the signal track 3, that is, the region where the ink is not printed on the scale plate 2, the light beam 1 a is reflected and reaches the light receiving element 4. To do. On the other hand, when the light beam 1a is applied to the non-reflecting portion 3b of the signal track 3 (the area where the ink that absorbs light is printed on the scale plate 2), the light beam 1a is not reflected and thus almost reaches the light receiving element 4. do not do. Therefore, the optical encoder 200 also detects the position on the scale plate 2 (signal track 3) irradiated with the light beam 1a, by analyzing the amount of light supplied to the light receiving element 4, similarly to the optical encoder 100. Can do.

  As with the ink 5 of the first embodiment, the ink of the non-reflecting portion 3b of the optical encoder 200 is also printed with an ink as an absorbent material for each fixed length in the extending direction of the scale plate 2. The density (the amount of ink printed per unit area, for example, the area of the region where the ink 5 is printed per unit area) may periodically change. In other words, the reflecting portion 3 a is a mode in which the density of the reflecting material, which is the first ink containing the metal powder that reflects the light emitted from the light emitting source 1, varies periodically depending on the position of the scale plate 2 in the extending direction. It is preferable that the configuration be such that (changes periodically).

  For example, as shown in FIG. 4, the optical encoder 200 according to the second embodiment may be made of a scale plate 2 itself made of a metal material such as aluminum or nickel that reflects light. However, for example, as in the optical encoder 200 of FIG. 5, a metal coating 2 a that reflects light is disposed on the surface of the scale plate 2 that is irradiated with the light beam 1 a, and the metal coating 2 a is on the surface. The structure which the ink which absorbs (shields) the light mentioned above in the area | region which is not arrange | positioned may be printed.

  In other words, in the case of the optical encoder 200 shown in FIG. 5, in the signal track 3, the area where the metal coating 2a is formed becomes the reflection part 3a, and the area where the ink is printed becomes the non-reflection part 3b. In FIG. 5, the metal coating 2a is formed in all regions on the surface irradiated with the light beam 1a except for the non-reflective portion 3b. However, the metal coating 2 a may be formed only on the reflection portion 3 a of the signal track 3.

  When the reflective portion 3a is formed by the metal coating 2a as in the optical encoder 200 of FIG. 5, the scale plate 2 itself is not only a highly reflective metal material but also a light such as a resin or a glass-based material. You may be comprised from the various material which does not reflect. And it is preferable to form the metal film 2a which consists of material with high reflectivity, such as gold | metal | money, silver, aluminum, nickel, on one surface of the said scale board 2 using plating, metal vapor deposition, sputtering method etc. It is preferable that the metal coating 2a is formed at least on the reflection portion 3a of the signal track 3 and then the non-reflection portion 3b is printed with ink that does not reflect light (absorbs light).

  The second embodiment of the present invention is different from the first embodiment of the present invention only in each point described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the second embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 3)
The present embodiment is different from the first embodiment in the direction in which the light emitted from the light emitting source 1 travels. Hereinafter, the configuration of the present embodiment will be described.

  The optical encoder 100 of Embodiment 1 supplies the light to the light receiving element 4 by reflecting the light emitted from the light emitting source 1 on the scale plate 2. However, like the optical encoder 300 of the present embodiment shown in FIG. 6, for example, the light emitted from the light source 1 may be transmitted through the scale plate 2 to supply the light to the light receiving element 4.

  In the optical encoder 300, the signal track 3 arranged at the same position as the optical encoder 100 includes a transmission part 3 c that transmits light emitted from the light source 1 and a non-transmission part 3 d that does not transmit light. A plurality are arranged at regular intervals in the extending direction of the plate 2. In the non-transmissive portion 3d, as with the reflective portion 3a of the optical encoder 100, for example, ink as a reflective material containing a metal powder that reflects light is printed so that the density changes depending on the position. Note that black ink disposed in the non-reflective portion 3b of the optical encoder 200 may be disposed in the non-transmissive portion 3d. In this case, light absorption occurs in the non-transmissive portion 3d. On the other hand, ink is not printed on the transmission part 3c. The scale plate 2 is made of a material that transmits light.

  Here, in the optical encoder 300, the illuminance of light reaching the light receiving element 4 is determined according to the density of the ink printed on the non-transmissive portion 3d. In other words, as with the optical encoder 100, the optical encoder 300 can detect the movement amount of the linearly moving member with a smaller number of parts and with high accuracy by using the non-transmissive portion 3d and the transmissive portion 3c formed by printing. Has the effect of being able to.

  In FIG. 6, the displacement control member 10 is disposed below the scale plate 2, and the light beam 1 a is shown to pass through the displacement control member 10. However, this is illustrated in the same manner as the optical encoder 100 of FIG. 1 in order to explain that the scale plate 2 is arranged so as to be attached to the displacement control member 10. Actually, it is preferable that a slit or the like is formed in the displacement control member 10 so that the light beam 1a can pass through the displacement control member 10.

  The third embodiment of the present invention is different from the first embodiment of the present invention only in each point described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the third embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 4)
In the present embodiment, the moving direction of the moving member is different from that in the first embodiment. Hereinafter, the configuration of the present embodiment will be described.

  For example, in the optical encoder 100 shown in FIG. 1, the moving member moves in the linear direction. On the other hand, for example, like the optical encoder 400 shown in FIG. 7, the displacement control member 12 may be a member for controlling the rotation angle (phase). The displacement control member 12 here is connected to a motor (not shown), for example, and is a motor shaft for transmitting the rotation of the motor to the rotating body 11.

  The displacement control member 12 of the optical encoder 400 corresponds to the displacement control member 10 of the optical encoder 100, and the rotating body 11 of the optical encoder 400 corresponds to the scale plate 2 of the optical encoder 100.

  Also in this case, like the scale plate 2 of the optical encoder 100, the rotator 11 is made of a material that does not reflect the light emitted from the light source 1, and the scale plate 2 includes a reflection portion 3a and a non-reflection portion 3b. The track 3 is printed in an annular shape. On the upper surface of the reflecting portion 3a, the density periodically changes at every fixed length in the circumferential direction of the circle formed by the rotating body 11 (at every fixed rotation angle (phase) related to the circle formed by the rotating body 11). Ink 5 is printed as shown.

  Similar to the optical encoder 100, the optical encoder 400 rotates the motor by utilizing the fact that light emitted from the light source 1 is reflected and the illuminance supplied to the light receiving element 4 is determined according to the amount of rotation of the motor, for example. The amount can be detected with high accuracy. For this reason, the amount of rotation of the motor can be controlled with high accuracy by feeding back the information on the amount of rotation to the motor, for example.

  In the optical encoder 400 that is displaced in the rotational direction as described above, for example, the rotating body 11 is made of a material that reflects light as in the second embodiment, and the light is transmitted as in the non-reflecting portion 3b of the signal track 3. A configuration in which ink made of a material that does not reflect (absorbs or shields) is printed may be used. Alternatively, the optical encoder 400 may be configured to supply light that passes through the rotating body 11 to the light receiving element 4 as in the third embodiment.

  The fourth embodiment of the present invention is different from the first embodiment of the present invention only in each point described above. That is, in the fourth embodiment of the present invention, all the configurations, conditions, procedures, effects, and the like not described above are in accordance with the first embodiment of the present invention.

(Embodiment 5)
The present embodiment is different from the first embodiment in the ink printed on the reflecting portion 3a. Hereinafter, the configuration of the present embodiment will be described.

  As shown in FIG. 8, a plurality of inks filled with a plurality of metal powder materials having different reflectivities are applied to the reflecting portion 3a of the optical encoder 100 according to the fifth embodiment in the direction in which the scale plate 2 extends. The types are printed in parallel. That is, the reflecting portion 3a has a configuration in which ink including a plurality of metal powders having different reflectivities according to the position in the extending direction of the scale plate 2 is arranged.

  The mode of ink in the reflecting portion 3a of the optical encoder 100 of the fifth embodiment is as shown in FIG. The left-right direction in FIG. 8 is the direction in which the scale plate 2 extends in the same manner as the left-right direction of the reflecting portion 3a in FIG. At each position in the left-right direction of the scale plate 2, the type of ink printed on the reflecting portion 3a is changed.

  Specifically, as shown in FIG. 8, for example, chrome ink 6 having a relatively low reflectivity with respect to light emitted from the light source 1 is printed in a region near the end in the left-right direction of the reflecting portion 3 a. The chrome-based ink 6 is an ink filled with chrome metal powder. It is preferable to print the aluminum-based ink 7 and the silver-based ink 8 that are inks having higher reflectivity with respect to the light emitted from the light emitting source 1 in the region closer to the central portion in the left-right direction of the reflecting portion 3a. Here, the silver-based ink 8 is the same ink as the ink 5 described in the first embodiment and filled with silver metal powder. The aluminum-based ink 7 is ink filled with aluminum metal powder.

  In FIG. 8, ink made of three kinds of metal powder is printed inside the reflection portion 3a. However, ink made of a greater variety of metal powders may be printed. Even in such a case, it is preferable that printing is performed so that the reflectance with respect to the light emitted from the light emitting source 1 gradually increases from the end portion in the left-right direction of the reflecting portion 3a toward the center portion.

  Also in this case, the reflectance of the light emitted from the light source 1 is continuously changed (inclined) with respect to the extending direction of the signal track 3 (scale plate 2). For this reason, if the position regarding the extending direction of the scale plate 2 irradiated with the light beam 1a changes, the light beam 1a is reflected and the ratio supplied to the light receiving element 4 changes. Further, since the light is hardly reflected at the non-reflective portion 3b, the chrome ink 6 having a low reflectance is printed at the end portion in the left-right direction of the reflective portion 3a that is relatively close to the non-reflective portion 3b among the reflective portions 3a. The Accordingly, with respect to the direction in which the scale plate 2 extends, the difference in reflectance is small even at the boundary between the reflecting portion 3a and the non-reflecting portion 3b.

  As described above, instead of changing the reflectance by changing the density of the ink printed on the reflective portion 3a, the reflectance may be changed by changing the type of ink printed on the reflective portion 3a.

  As described above, while using a plurality of types of ink, as in the first embodiment, for example, the printing density of each type of ink and the density of the metal powder filled in each type of ink are changed. It is good also as the structure made to do. In this way, it is possible to detect the reflectance information that changes according to the position with higher accuracy. Further, a plurality of types of inks may be used as the ink as the absorbing material in the second embodiment. Furthermore, each optical encoder shown in Embodiment 3 or Embodiment 4 may be configured to use a plurality of types of ink as described in this embodiment.

  The fifth embodiment of the present invention is different from the first embodiment of the present invention only in the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the fifth embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 6)
The present embodiment is different from the first embodiment in the ink that is printed on the reflecting portion 3a. Hereinafter, the configuration of the present embodiment will be described.

  As the ink 5 (see FIGS. 1 to 3) to be printed on the reflecting portion 3a, an inorganic substance having an effect of amplifying the reflectance is filled instead of the ink 5 filled with the powder of the metal material having a high reflectance. Ink 5 (second ink) may be used. Here, for example, silicon (Si), tantalum (Ta), or titanium (Ti) is preferably used as the inorganic substance filled in the ink 5. That is, the reflecting portion 3a has a configuration in which the density of the second ink, which is a reflecting material including an inorganic substance that reflects the light emitted from the light emitting source 1, is changed according to the position.

  Even if the optical encoder 100 similar to that of the first embodiment is formed using the ink 5 filled with such an inorganic material, the same effect as that of the first embodiment is obtained.

  Note that the optical encoder described in Embodiment 4 may have a configuration using the ink 5 filled with the inorganic substance described in this embodiment.

  The sixth embodiment of the present invention is different from the first embodiment of the present invention only in each point described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the sixth embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 7)
This embodiment is different from the first embodiment in the mode of ink printed on the signal track 3. Hereinafter, the configuration of the present embodiment will be described with reference to FIG.

  In the present embodiment, the signal track 3 on the scale plate 2 does not include the reflecting portion 3a and the non-reflecting portion 3b, and the ink 5 as a reflecting material is printed on almost the entire surface of the signal track 3. . The printing density of the ink 5 is printed so as to periodically change for every certain length in the extending direction of the scale plate 2. The ink 5 may be, for example, an ink filled with silver metal powder as in the first embodiment, or a plurality of metal powders periodically change in the left-right direction in FIG. 9 as in the fifth embodiment. It may be printed as follows. Alternatively, an ink filled with an inorganic substance as in the sixth embodiment may be used.

  Thus, even if the non-reflecting portion 3b is not provided and the ink 5 is printed on almost the entire surface of the signal track 3, the same effect as that in the case where the reflecting portion 3a and the non-reflecting portion 3b are provided is basically the same. Play.

  In addition, when the non-reflecting part 3b is provided like Embodiment 1, the change of the reflectance according to the position in the one non-reflecting part 3b cannot be detected. This is because the reflectance of the light emitted from the light emitting source 1 is the same (almost not reflected) in any region within one non-reflective portion 3b. However, in the seventh embodiment, since the non-reflective portion 3b does not exist, the reflectance changes at any position on the signal track 3 in the extending direction of the scale plate 2. For this reason, for example, the movement amount can be detected with high accuracy regardless of the movement amount of the linear movement member.

  As in the seventh embodiment, a configuration in which the non-reflecting portion 3b is not provided and the reflective material is printed on almost the entire region on the signal track 3 may be used in, for example, the second to fifth embodiments. As in the second embodiment, when ink as an absorbing material is printed instead of a reflecting material over almost the entire area of the signal track 3 so that the density changes periodically, the light absorption rate (in other words, depending on the area) The reflectance) can be changed. In Embodiment 3, it is preferable that the ink as the non-permeable material is printed as shown in FIG. In the fifth embodiment, it is preferable that a plurality of types of inks are continuously arranged in parallel with respect to the extending direction of the scale plate 2 (without providing the non-reflecting portion 3b).

  The seventh embodiment of the present invention differs from the first embodiment of the present invention only in the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the seventh embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 8)
This embodiment is different from the first embodiment in the mode of ink printed on the signal track 3. Hereinafter, the configuration of the present embodiment will be described with reference to FIGS. 10 and 11.

  In the first embodiment, the density at which the ink 5 of the reflecting portion 3a is printed and the density at which the metal powder is filled in the printed ink 5 vary depending on the position of the scale plate 2 in the extending direction. Let On the other hand, in Embodiment 8, the ink 5 of the reflecting portion 3a has a configuration in which the printed thickness is changed in accordance with the position in the extending direction of the scale plate 2.

  Referring to the top view of FIG. 10 and the cross-sectional view of FIG. 11, the ink 5 is preferably printed so that the end of the reflecting portion 3a in the extending direction of the scale plate 2 is thicker and the center is thinner. . For this reason, as shown in the cross-sectional view of FIG. 11, the ink 5 of the reflecting portion 3a is printed so as to have a substantially concave shape. In order to change the reflectance continuously (inclining) in the extending direction of the scale plate 2, the thickness of the ink 5 changes continuously (inclining). Yes.

Even with such a configuration, the same effects as those of the first embodiment can be obtained.
However, the reflectance of the light emitted from the light source 1 increases as the area where the ink 5 is printed thicker. That is, the reflection part 3a of FIGS. 10 and 11 has a higher light reflectivity at the end part in the extending direction of the scale plate 2.

  In the second, third, fourth, sixth, and seventh embodiments, the ink is printed so that the ink density changes periodically, and the ink thickness changes periodically as in the eighth embodiment. It is good also as an aspect which printed the ink.

  The eighth embodiment of the present invention is different from the first embodiment of the present invention only in each point described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the eighth embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 9)
This embodiment is different from the first embodiment in the mode of ink printed on the signal track 3. Hereinafter, the configuration of the present embodiment will be described with reference to FIGS. 12 and 13.

  In the ninth embodiment, similarly to the eighth embodiment, the ink 5 of the reflecting portion 3a has a configuration in which the printed thickness is changed according to the position in the extending direction of the scale plate 2. However, referring to the top view of FIG. 12 and the cross-sectional view of FIG. 13, the ink 5 is printed so that the end of the reflecting portion 3a in the extending direction of the scale plate 2 is thinner and thicker at the center.

  In this case, in order to make the change in the reflectance at the end of the reflecting portion 3a (that is, the boundary portion with the non-reflecting portion 3b) continuous, the material of the scale plate 2 is the same as in the first embodiment. It is preferable that the light source 1 is formed of a material that does not reflect light.

Even with such a configuration, the same effects as those of the first embodiment can be obtained.
As shown in FIGS. 12 and 13, in the ninth embodiment, the thickness of the ink 5 with respect to the extending direction of the scale plate 2 is changed in a stepped manner. However, also in the ninth embodiment, as in the eighth embodiment, the thickness may be changed continuously (inclined). When the thickness of the ink 5 is changed stepwise as shown in FIGS. 12 and 13, the change in thickness is made as fine as possible (the number of steps in FIGS. 12 and 13 is increased as much as possible, and the scale plate 2 of each step is changed. It is preferable to reduce the width in the extending direction. In this way, the change in the thickness of the ink 5 becomes close to a continuous (inclined) change. That is, the reflectance can be continuously changed (with respect to the direction in which the scale plate 2 extends).

  In the second, third, fourth, sixth, and seventh embodiments, the ink is printed so that the ink density periodically changes, and the ink thickness changes periodically as in the ninth embodiment. It is good also as an aspect which printed the ink.

  The ninth embodiment of the present invention is different from the first embodiment of the present invention only in each point described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the ninth embodiment of the present invention are all in accordance with the first embodiment of the present invention.

(Embodiment 10)
This embodiment is different from the first embodiment in the aspect of the signal track 3. Hereinafter, the configuration of the present embodiment will be described with reference to FIGS. 14 and 15.

  14 and 15, the signal track 3 of the present embodiment extends to the central portion in the width direction of the scale plate 2 and is periodically concave and convex in the extending direction of the scale plate 2. The shape is formed. In this respect, the configuration is different from the signal track 3 of the first embodiment, which is simply configured to be printed as an area of the signal track 3.

  That is, the signal track 3 of the present embodiment has an uneven shape formed on the main surface of the scale plate 2 (a rectangular surface formed by the extending direction of the scale plate 2 and the width direction intersecting with the extending direction). And the ink 5 as a reflection part is printed on the convex upper part.

Even with such a configuration, the same effects as those of the first embodiment can be obtained.
The ink 5 may be a first ink filled with a metal powder that reflects light as in the first embodiment, or a first ink filled with a reflective material containing an inorganic substance as in the sixth embodiment. Two inks may be used.

  Further, for example, in the second, third, fourth, sixth, and seventh embodiments, instead of printing the ink of the reflecting material, the signal track 3 is formed to have an uneven shape as in the present embodiment. May be.

Next, a method for manufacturing the scale plate 2 according to the present embodiment will be described.
First, by performing, for example, an injection molding method using, for example, a thermoplastic resin, the shape of the scale plate 2 having irregularities formed on the main surface as shown in FIG. 14 (FIG. 15) is formed. In place of the injection molding method, for example, hot embossing, roll molding method, pressing method or the like may be used.

  Next, as shown in FIG. 16, the ink to be printed is applied onto the side surface of the cylindrical ink application roller 14 which is a part of the printing apparatus, for example, and the side surface of the ink application roller 14 is formed first. The scale plate 2 is rotated while being brought into contact with the convex surface. In this way, as shown in FIG. 17, the scale plate 2 on which the ink 5 as the reflective material is printed on the convex surface is formed.

  Alternatively, for example, when forming the scale plate 2 used in the optical encoder 300 having a specification for transmitting the light from the light source 1 as in the third embodiment, the black surface such as paint is formed on the convex surface. Ink may be printed. In this way, light can be absorbed on the convex surface, so that the light transmittance can be reduced. In this case, for example, the scale plate 2 may be made of a transparent material such as glass in order to transmit light more in the region other than the convex shape of the scale plate 2.

  The tenth embodiment of the present invention differs from the first embodiment of the present invention only in the points described above. That is, the configuration, conditions, procedures, effects, and the like that have not been described above for the tenth embodiment of the present invention are all in accordance with the first embodiment of the present invention.

  As described above, the reflectivity of the signal track 3 according to each embodiment of the present invention is arbitrarily variable in accordance with the printed density, the type of printed reflective material, and the printed thickness. Can be controlled. Therefore, the illuminance distribution received by the light receiving element 4 can be highly accurate and less distorted, and information on the amount of movement (rotation angle) of the displacement control member 10 (12) can be detected with higher accuracy.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is particularly excellent as a technique for manufacturing an optical encoder at a lower cost.

  1 Light source, 1a beam, 2 scale plate, 2a metal coating, 3 signal track, 3a reflecting part, 3b non-reflecting part, 3c transmitting part, 3d non-transmitting part, 4 light receiving element, 5 ink, 6 chrome ink, 7 Aluminum-based ink, 8 Silver-based ink, 10,12 Displacement control member, 11 Rotating body, 14 Ink application roller, 100, 200, 300, 400 Optical encoder.

Claims (10)

A scale plate installed on the displacement control member;
A light emitting source for supplying light to irradiate the scale plate;
An optical encoder comprising a light receiving element that detects the light irradiated on the scale plate;
The scale plate is provided with a signal track that includes a reflective material for reflecting the light and changing the amount of the light incident on the light receiving element,
In the signal track, the reflective material is printed periodically with respect to the direction along the displacement direction of the displacement control member ,
The signal track has a reflective portion including the reflective material, and a non-reflective portion where the reflective material is not disposed,
Concave and convex shapes are formed on the main surface of the scale plate,
In the signal track, an optical encoder in which the reflecting material for forming the reflecting portion is disposed on a convex portion of the uneven shape of the scale plate . 2. The optical type according to claim 1 , wherein the reflective material disposed on the convex portion is a first ink containing a metal powder that reflects the light or a second ink containing an inorganic substance that reflects the light. Encoder. The optical encoder according to claim 1 , wherein the reflective material disposed on the convex portion is black ink. The scale plate is made of a material that absorbs the light, the optical encoder according to any one of claims 1-3. The scale plate is made of a material that transmits the light, the optical encoder according to any one of claims 1-3. The optical encoder according to any one of claims 1 to 5 , wherein a planar shape of the scale plate is an annular shape. The optical encoder according to any one of claims 1 to 5 , wherein a planar shape of the scale plate is a strip shape extending linearly. A scale plate installed on the displacement control member;
A light emitting source for supplying light to irradiate the scale plate;
An optical encoder comprising a light receiving element that detects the light irradiated on the scale plate;
On the scale plate, a signal track including an absorbing material for absorbing or shielding the light and changing the amount of the light incident on the light receiving element is disposed,
In the signal track, the absorbent material is printed periodically with respect to the direction along the displacement direction of the displacement control member ,
An optical encoder, wherein an uneven shape is formed on a main surface of the scale plate . The optical encoder according to claim 8 , wherein the signal track includes a reflection portion on which a metal film that reflects the light is disposed, and a non-reflection portion including the absorber. Scale plate constituting the optical encoder according to any one of claims 1-9.