JP5052391B2 - Optical encoder - Google Patents

Description

  The present invention relates to an optical encoder that detects the position and the like of an object to be detected.

FIGS. 9A and 9B show an example of a small and thin optical encoder disclosed in Japanese Patent Laid-Open No. 2005-283457. The light source 102, the scale 200 having a lattice pattern that transmits or reflects light emitted from the light source 102, and the photodetector 104 that receives light transmitted or reflected by the scale 200. The light source 102 and the photodetector 104 constitute a sensor head 100. 9A and 9B, the light source 102 and the photodetector 104 are disposed at predetermined positions on the wiring board 106, and the transparent resin 118 is provided on the wiring board 106, the light source 102, and the photodetector 104. Covered. Further, a front surface electrode 112, a rear surface electrode 116, and an extraction electrode 114 are formed on the wiring substrate 106, and the light source 102 and the front surface electrode 112, and the semiconductor IC 108 and the front surface electrode 112 are electrically connected by a conductive wire 110. By adopting such a configuration, a small and thin sensor head 100 of a reflective encoder can be obtained.
JP 2005-283457

  In the configuration in which the light source 102, the photodetector 104, and the like are completely covered with the transparent resin 118 as in the conventional optical encoder described above, when the static electricity is charged in the transparent resin 118, the light source 102 and the light detection are detected. A current due to static electricity flows through a circuit in the semiconductor IC 108 in which the device 104 is formed. Depending on the magnitude of this current, a semiconductor functional element (so-called MOS or the like) in the semiconductor IC 108 may be destroyed. Such static electricity is generated, for example, when the surface of the resin 118 of the sensor head 100 is touched or rubbed with tweezers 500 or the like as shown in FIGS. 10A and 10B. The amount generated is large.

  In some cases, the static electricity generated and charged on the surface of the resin 118 flows to the extraction electrode 114 formed on the wiring substrate 106 through the semiconductor functional element in the semiconductor IC 108 via the electrode formed in the semiconductor IC 108 in which the photodetector 104 is formed. In many cases, the semiconductor functional element is destroyed depending on the amount of charge. Such destruction frequently occurs in a process in which the sensor head 100 comes into contact with or separates from some equipment in the manufacturing process of the sensor head 100, the process of attaching the sensor head 100 to the apparatus, and the like. The mechanism of destruction caused by static electricity described here is merely an example, and the charge generated when contacting the resin 118 is not limited to a negative value but may be a positive value.

  For example, as shown in FIG. 11, in the case where the optical member 41 such as glass is arranged on the light source 102, when the moisture 400 penetrates into the resin 118, the moisture 400 is interposed between the optical member 41 and the resin 118. Accumulation may occur and separation may occur between the optical member 41 and the resin 118, and the optical refractive index changes due to this separation, resulting in degradation of the optical encoder signal. Furthermore, when the moisture 400 penetrates into the resin 118 and accumulates in the electrode member such as the surface electrode 112, a poor electrical conduction due to corrosion of the electrode occurs.

  The present invention has been made paying attention to such problems, and the object of the present invention is to prevent the optical encoder from being damaged by static electricity and to improve the yield in manufacturing and mounting on the apparatus. An object of the present invention is to provide an optical encoder capable of performing

  In order to achieve the above object, an optical encoder according to a first aspect of the present invention includes a sensor head having one or more light sources and one or more photodetectors, and is moved relative to the sensor head. An optical system configured to output a displacement signal indicating a positional relationship between the sensor head and the scale by receiving light emitted from the light source by the photodetector through the scale. The sensor head includes a wiring board on which electrodes are formed and the light source and the photodetector are arranged at predetermined positions, the wiring board, the light source, and the photodetector. The first conductive member is disposed on at least a part of the surface of the resin.

  In the optical encoder according to the second aspect of the present invention, in the optical encoder according to the first aspect, the first conductive member transmits light from the light source.

  The optical encoder according to the third aspect of the present invention is the optical encoder according to the first aspect, wherein the first conductive member is made of a metal oxide.

  An optical encoder according to a fourth aspect of the present invention is the optical encoder according to the first aspect, wherein the electrode formed on the wiring board and the first conductive member are second conductive members. Are electrically connected.

  An optical encoder according to a fifth aspect of the present invention is the optical encoder according to the fourth aspect, wherein the second conductive member is disposed inside the resin of the sensor head.

  An optical encoder according to a sixth aspect of the present invention is the optical encoder according to the first aspect, wherein the first conductive member is disposed over the entire surface of the resin.

  An optical encoder according to a seventh aspect of the present invention is the optical encoder according to the first aspect, wherein a cleaning functional material is disposed on at least a part of the first conductive member.

  According to the present invention, destruction of the optical encoder due to static electricity can be prevented, and the yield at the time of manufacturing and mounting to the apparatus can be improved.

(First embodiment)
FIG. 1 is a diagram showing a configuration of an optical encoder according to a first embodiment of the present invention. The optical encoder shown in FIG. 1 includes a sensor head 1 having a light source 4 and a photodetector 5 inside, and a scale 2 having a lattice pattern that moves linearly relative to the sensor head 1. It is a reflective optical encoder.

  More specifically, electrodes are formed on the sensor head 1, and a light source 4 such as an LED or a semiconductor laser, and one or more photodetectors 5 are formed on a wiring board 3 made of a material such as ceramic or resin. The semiconductor IC 51 is mounted. Further, the light source 4 and the semiconductor IC 51 are electrically connected to the front surface electrode 312 formed on the wiring substrate 3 by the conductive wire 8 and the like, and are also electrically connected to the back surface electrode 314 through the extraction electrode 313.

  Further, the entire wiring board 3 including the light source 4, the semiconductor IC 51, and the conductive wire 8 is covered with a resin 6 that transmits the wavelength light of the light source 4, and the conductive member 7 (the wavelength 6 of the light source 4 is transmitted on the resin 6. The first conductive member) is arranged.

  Here, the sensor head surface from which the light of the main axis emitted from the light source 1 is emitted and the sensor head surface from which the emitted light is reflected or diffracted by the scale 2 are referred to as the surface of the sensor head 1.

  Next, a method for manufacturing the sensor head 1 will be described with reference to FIGS. 6, 7A, and 7B. FIG. 6 shows a state in which a large number of sensor heads 1 are formed on a large-sized substrate 31 made of one piece of ceramic or resin. 7A and 7B are cross-sectional views taken along the line A-A 'of the configuration of FIG.

  In manufacturing the sensor head 1, a large number of front surface electrodes 312, extraction electrodes 313, and back surface electrodes 314 of the wiring substrate 3 are formed side by side on a large substrate 31. Further, components such as the light source 4 and the semiconductor IC 51 are mounted on the wiring board 3 at desired positions. Here, the extraction electrode 313 is formed by a method of opening a through hole in the large substrate 31 and embedding a conductive member.

  Further, the light source 4 and the semiconductor IC 51 are electrically connected to the surface electrode 312 of the wiring board 3 by a conductive wire 8 or the like. Next, the light source 4, the semiconductor IC 51, the conductive wire 8, and the wiring substrate 3 are covered with a resin 6 that transmits the wavelength light of the light source 4 such as epoxy or silicon.

  FIG. 7A shows a state when the resin 6 is molded, and FIG. 7B shows a state when the resin 6 is potted for each area of one sensor head 1.

  Next, as shown in FIGS. 7C and 7D, a conductive metal oxide film is formed as a conductive member 7 on the resin 6. Examples of the metal oxide film include an indium and tin oxide film (so-called ITO) and a tin oxide film. Examples of the film forming method include vacuum film forming methods such as vapor deposition or sputtering, printing methods such as offset or letterpress, spin coating methods, and spraying methods. An example of the thickness of the conductive metal oxide film is a thickness of several tens nm to several μm that transmits the wavelength light of the light source 4.

  Finally, the large substrate 31 is cut along with the resin 6 along the cutting line 311 to complete the sensor head 1. The above is an example of the manufacturing method and is not limited to this method.

  Next, attachment of the sensor head 1 manufactured as described above and the scale 2 having a lattice pattern will be described. For example, there is an encoder having a configuration in which a highly accurate displacement signal can be obtained by making the photodetector 5 have a rectangular shape and aligning the long side thereof with the long side of the lattice pattern of the scale 2 in parallel. Here, the displacement signal is a signal indicating the positional relationship between the scale 3 and the sensor head 1, and is a two-phase phase that changes periodically according to the relative movement between the scale 3 and the sensor head 1 and whose phase is shifted by 90 degrees. Analog signal or a digital signal obtained by converting the analog signal by a signal processing circuit. In this case, the semiconductor IC 51 is arranged so that the long side of the photodetector 5 is perpendicular to the cutting line 311.

  The scale 2 is formed with an outer surface or a matching pattern perpendicular to the long side of the lattice pattern, and an outer surface perpendicular to the long side of the lattice pattern and a cutting line 311 perpendicular to the long side of the photodetector 5. If the sensor head 1 and the scale 2 are attached by aligning the position with the surface cut in step 1, a highly accurate displacement signal can be obtained. Here, the alignment refers to visual observation, image recognition, or application to an auxiliary member.

  Next, the operation of the embodiment of the present invention will be described. As shown in FIG. 1, since a conductive film (here, a conductive metal oxide film) is formed on the resin 6 of the sensor head 1 as the conductive member 7, the manufacturing process or when the sensor head 1 is attached to a desired apparatus. Even if the surface of the sensor head 1 is touched or rubbed with another member, static electricity as described with reference to FIG. 10 does not occur. Accordingly, even if the resin 6 surface of the sensor head 1 is touched or rubbed with another member, the semiconductor functional element mounted in the semiconductor IC 51 is not destroyed, so that the manufacturing yield and the attachment of the sensor head 1 to the device are prevented. The yield of time will be improved.

  In addition, in order to solve the problem of moisture penetration described with reference to FIG. 11, the conductive member 7 is made of a metal oxide that has a moisture permeability smaller than that of the resin 6 and is not oxidized by moisture. Penetration can be suppressed. As a result, the deterioration of the optical encoder signal and the electrical continuity failure due to the corrosion of the electrode member as described above can be prevented, and an optical encoder with a stable output signal and high reliability can be obtained.

  Of course, various modifications and changes can be made to each configuration of the embodiment of the present invention. For example, as shown in FIG. 8, even if the conductive member 7 is formed on a part of the surface of the sensor head 1 that does not affect the emitted light and the incident light (a part other than the central part through which the emitted light and the incident light pass). Good.

  Further, the light source 4 and the light detector 5 are not limited to one, and a large number of them may be arranged, and the lattice pattern of the scale 2 is not limited to one type, and various types may be formed. In addition to the photodetector 5, the semiconductor IC 51 may be equipped with a circuit for converting an analog signal into a digital signal, an interpolation / division circuit, a light source driver, and the like. As an electrical connection method, in addition to the conductive wire 8, a back surface wiring may be applied to the semiconductor IC 51 and connected to the wiring substrate 3 with solder or the like. In addition, an optical member may be provided on the light source 4.

  Furthermore, the conductive metal oxide as the conductive member 7 is not limited to ITO and tin oxide, and may be any material that exhibits conductivity such as zinc oxide. Further, the scale 2 is not limited to a linear movement relative to the sensor head 1 but may be a rotational movement relatively. Further, the extraction electrode 313 may be extracted from any of the four side surfaces.

(Second Embodiment)
FIG. 2 is a diagram showing a configuration of an optical encoder according to the second embodiment of the present invention. The optical encoder shown in FIG. 2 is a reflection composed of a sensor head 1 having a light source 4 and a photodetector 5 inside, and a scale 2 having a lattice pattern that moves linearly relative to the sensor head 1. Type optical encoder.

  Here, in the sensor head 1 in the second embodiment, the silver between the conductive member 7 disposed on the surface of the resin 6 and the ground electrode 31 connected to the ground formed on the wiring board 3 is disposed on the surface of the resin 6. The conductive member 18 (second conductive member) such as paste is electrically connected. The rest of the configuration is the same as in the first embodiment, and a description thereof will be omitted. Here, the electrode formed on the wiring board 3 to be electrically connected using the conductive member 18 is not limited to the ground electrode 31 and may be another electrode.

  The difference between the manufacturing method of the sensor head 1 according to the second embodiment and the first embodiment is that the large substrate 31 is cut along with the resin 6 along the cutting line 311 and then the surface of the resin 6 is cut. The only difference is that the number of steps of electrically connecting the conductive member 7 arranged on the ground and the ground electrode 31 connected to the ground formed on the wiring board 3 by the conductive member 18 such as silver paste is increased. The description is omitted because it is similar.

  Further, since the mounting of the sensor head 1 and the scale 2 having the lattice pattern is the same as that of the first embodiment, the description thereof is omitted.

  The operation of the embodiment of the present invention has the same operation as that of the first embodiment and further has the following operation. That is, the conductive member 7 is always kept at the same potential as the ground electrode 31 by electrically connecting the conductive member 7 formed on the resin surface and the ground electrode 31 connected to the ground formed on the wiring board 3. . As a result, generation of static electricity can be further suppressed than in the first embodiment, and therefore the possibility of destruction of the semiconductor functional element in the semiconductor IC due to static electricity can be further reduced. Therefore, the yield is further improved when the sensor head 1 is manufactured and attached to the apparatus.

  Each configuration of the embodiment of the present invention can be variously modified and changed in the same manner as in the first embodiment.

(Third embodiment)
FIG. 3 is a diagram showing a configuration of an optical encoder according to the third embodiment of the present invention. The optical encoder shown in FIG. 3 is a reflection composed of a sensor head 1 having a light source 4 and a photodetector 5 inside, and a scale 2 having a lattice pattern that moves linearly relative to the sensor head 1. Type optical encoder.

  Here, the sensor head 1 includes a conductive member 18 ′ (second conductive member) disposed between the conductive member 7 disposed on the surface of the resin 6 and the ground electrode 31 connected to the ground formed on the wiring substrate 3 inside the resin 6. ) Is electrically connected. The rest of the configuration is the same as in the first embodiment, and a description thereof will be omitted.

  The difference between the manufacturing method of the sensor head 1 and the first embodiment is that the conductive member 18 ′ made of aluminum or the like is similarly applied when components such as the light source 4 and the semiconductor IC 51 are mounted on the wiring board 3 at desired positions. Is arranged on the ground electrode 31. Here, when the conductive member 7 is formed, the thickness of the conductive member 18 'is made larger than the thickness of the resin 6 so that the conductive member 18' and the conductive member 7 are in direct contact with each other to make an electrical contact. It should not be formed on the upper surface of 18 '. Note that the method is not limited to this method as long as the ground electrode 31 and the conductive member 7 are electrically connected. Others are the same as those in the first embodiment, and a description thereof will be omitted. Further, since the mounting of the sensor head 1 and the scale 2 having the lattice pattern is the same as that of the first embodiment, the description thereof is omitted.

  The operation of the embodiment of the present invention has the same operation as that of the first embodiment and further has the following operation. That is, the conductive member 7 is always kept at the same potential as the ground electrode 31 by electrically connecting the conductive member 7 formed on the resin surface and the ground electrode 31 connected to the ground formed on the wiring board 3. It is. As a result, the generation of static electricity can be further suppressed than in the first embodiment, and therefore the destruction of the semiconductor functional elements in the semiconductor IC due to static electricity can be further prevented. Therefore, the yield is further improved when the sensor head 1 is manufactured and attached to the apparatus.

  Each configuration of the embodiment of the present invention can be variously modified and changed in the same manner as in the first embodiment.

(Fourth embodiment)
FIG. 4 is a diagram showing a configuration of an optical encoder according to the fourth embodiment of the present invention. The optical encoder shown in FIG. 4 is a reflection composed of a sensor head 1 having a light source 4 and a light detector 5 inside, and a scale 2 having a lattice pattern that moves linearly relative to the sensor head 1. Type optical encoder.

  The difference from the first embodiment is that the conductive member 7 is formed over the entire surface of the resin 6 in the fourth embodiment, and the ground electrode 31 formed on the wiring board 3 is electrically connected. It is configured to contact. The other extraction electrodes 313 except for the ground electrode 31 are not formed on the side surface of the sensor head 1, but the extraction electrode 313 is formed in a through hole provided inside the sensor head 1 except for the side surface as shown in FIG. In this configuration, electrical contact is made between the back electrode 314 and the conductive member 7 except for the ground electrode 31. The rest of the configuration is the same as in the first embodiment, and a description thereof will be omitted.

  The difference from the first embodiment of the method for manufacturing the sensor head 1 is that the number of steps for forming the conductive member 7 on the side surface of the sensor head 1 is increased. As an example, the formation of the conductive member 7 on the resin 6 is not performed in the state of the large substrate 31, but vapor deposition or sputtering is performed in a state in which the large substrate 31 is cut along the cutting line 311. These are simultaneously formed on the surface and side surfaces of the sensor head 1 by a method such as a vacuum film forming method or a spray method. In addition, after manufacturing the sensor head 1 in the same process as in the first embodiment, the conductive member 7 may be formed on the side surface of the sensor head 1 by a method such as a spray method. Note that the above is an example, and the method of forming the conductive member 7 on the surface and side surfaces of the sensor head 1 is not limited to this. Others are the same as those in the first embodiment, and a description thereof will be omitted.

Since the sensor head 1 and the scale 2 having the lattice pattern are attached in the same manner as in the first embodiment, the description thereof is omitted.

  The operation of the embodiment of the present invention has the same operation as that of the first embodiment and further has the following operation. That is, the conductive member 7 is always formed not only on the resin surface but also on the side surface of the sensor head 1 and electrically connected to the ground electrode 31 formed on the wiring board 3, so that the conductive member 7 is always connected to the ground electrode 31. Is kept at the same potential. As a result, the generation of static electricity can be further suppressed than in the first embodiment, and therefore the destruction of the semiconductor functional elements in the semiconductor IC due to static electricity can be further prevented. Therefore, the yield is further improved when the sensor head 1 is manufactured and attached to the apparatus.

  Each configuration of the embodiment of the present invention can be variously modified and changed in the same manner as in the first embodiment.

(Fifth embodiment)
FIG. 5 is a diagram showing a configuration of an optical encoder according to the fifth embodiment of the present invention. The optical encoder shown in FIG. 5 is a reflection composed of a sensor head 1 having a light source 4 and a photodetector 5 inside, and a scale 2 having a lattice pattern that moves linearly relative to the sensor head 1. Type optical encoder.

  The difference between the fifth embodiment and the first embodiment is that the cleaning function member 71 is formed on the conductive member 7. The cleaning functional member 71 is a superhydrophilic material or a photocatalyst, and the most common material is titanium oxide including titanium dioxide. The rest of the configuration is the same as in the first embodiment, and a description thereof will be omitted.

  Further, the difference from the first embodiment of the method for manufacturing the sensor head 1 is that the number of steps for forming the cleaning function member 71 is increased. For example, after the conductive member 7 is formed on the surface of the resin 6, the cleaning function member 71 is formed on the conductive member 7 in the same manner as the conductive member 7. When forming a film, a thickness of several tens of nm to several μm that transmits the wavelength light of the light source 4 by a vacuum film forming method such as vapor deposition or sputtering, a printing method such as offset or letterpress, a spin coating method, or a spray method. To form a film. Further, after the sensor head 1 is manufactured in the same process as in the first embodiment, the cleaning function member 71 may be formed on the conductive member 7 of the sensor head 1 by the same method as described above. Note that the above is an example, and the method of forming the cleaning function member 71 is not limited to this. Others are the same as those in the first embodiment, and a description thereof will be omitted.

  Since the sensor head 1 and the scale 2 having the lattice pattern are attached in the same manner as in the first embodiment, the description thereof is omitted.

  The operation of the embodiment of the present invention has the same operation as that of the first embodiment and further has the following operation. That is, by forming a cleaning function member 71 such as titanium dioxide having the most common hydrophilic property and photocatalytic property on the surface of the sensor head 1, dew condensation is suppressed even if moisture adheres to the surface. And volatile stains are removed. As a result, characteristic changes such as optical refractive index due to condensation and dirt can be prevented, and a stable signal with high reliability can be obtained as an output signal of the optical encoder.

  Each configuration of the embodiment of the present invention can be variously modified and changed in the same manner as in the first embodiment. The cleaning function member 71 may be formed not only on the surface of the sensor head 1 but also on the side surface. The cleaning function member 71 is not limited to titanium dioxide, and may be a halogen catalyst, a metal oxide semiconductor photocatalyst, a metal sulfide semiconductor catalyst, a mixed semiconductor photocatalyst, or the like.

  Furthermore, as long as the cleaning function member 71 has a function as the conductive member 7, a structure having only one layer as the conductive cleaning function member may be used instead of the two-layer structure of the conductive member 7 and the cleaning function member 71.

(Appendix)
The invention having the following configuration is extracted from the specific embodiment.

1. A sensor head having one or more light sources and one or more photodetectors, and a scale movable relative to the sensor head, and the light emitted from the light sources is transmitted through the scales through the scale. An optical encoder that receives light by a photodetector and outputs a displacement signal indicating a positional relationship between the sensor head and the scale from the sensor head,
The sensor head includes an electrode and a wiring board on which the light source and the photodetector are arranged at predetermined positions, a resin that covers the wiring board, the light source, and the photodetector. And
An optical encoder, wherein a first conductive member is disposed on at least a part of the surface of the resin.

(Corresponding Embodiment of the Invention)
The first embodiment corresponds to the embodiment relating to the present invention.

(Function, effect)
By forming a conductive member on a part of the resin surface, static electricity is generated in the resin even when the sensor head surface is touched or rubbed when the sensor head is manufactured or attached to the device. It is possible to prevent destruction of the semiconductor functional element disposed in the sensor head.

  Therefore, it is possible to improve the yield when the sensor head is manufactured and when it is attached to the apparatus.

2. The optical encoder according to 1, wherein the first conductive member transmits light from the light source.

(Corresponding Embodiment of the Invention)
The first embodiment corresponds to the embodiment relating to the present invention.

(Function, effect)
Same as configuration 1.

3. 2. The optical encoder according to 1, wherein the first conductive member is made of a metal oxide.

(Corresponding Embodiment of the Invention)
The first embodiment corresponds to the embodiment relating to the present invention.

(Function, effect)
Encoder by peeling between optical member and resin due to moisture penetration, which is a problem in resin sealing, by making the conductive member a metal oxide that has the same moisture permeability as that of resin and does not undergo oxidation due to moisture. It is possible to prevent an electrical continuity failure due to signal deterioration and electrode member corrosion, and to obtain an optical encoder with stable signal and high reliability.

4). 2. The optical encoder according to 1, wherein the electrode formed on the wiring board and the first conductive member are electrically connected by a second conductive member.

(Corresponding Embodiment of the Invention)
The second embodiment corresponds to the embodiment relating to the present invention.

(Function, effect)
Since the structure is the same as the structure 1 and further measures for preventing electrostatic breakdown, the yield at the time of manufacturing the sensor head and mounting the sensor head is further improved.

5). 5. The optical encoder according to 4, wherein the second conductive member is disposed inside the resin of the sensor head.

(Corresponding Embodiment of the Invention)
The embodiment relating to the present invention corresponds to the third embodiment.

(Function, effect)
Same as configuration 4.

6). 2. The optical encoder according to 1, wherein the first conductive member is disposed on the entire surface of the resin.

The embodiment relating to the present invention corresponds to the fourth embodiment.

(Function, effect)
Same as configuration 4.

7). 2. The optical encoder according to 1, wherein a cleaning function material is disposed on at least a part of the first conductive member.

(Corresponding Embodiment of the Invention)
The fifth embodiment corresponds to the embodiment relating to the present invention.

(Function, effect)
Since the same function as in configuration 2 and the provision of the cleaning function material can prevent moisture from adhering and soiling, a stable encoder signal can be obtained.

FIG. 1 is a diagram showing a configuration of an optical encoder according to a first embodiment of the present invention. FIG. 2 is a diagram showing a configuration of an optical encoder according to the second embodiment of the present invention. FIG. 3 is a diagram showing a configuration of an optical encoder according to the third embodiment of the present invention. FIG. 4 is a diagram showing a configuration of an optical encoder according to the fourth embodiment of the present invention. FIG. 5 is a diagram showing a configuration of an optical encoder according to the fifth embodiment of the present invention. It is a figure for demonstrating the manufacturing method of the sensor head 1, and has shown the state in which many sensor heads were formed in the large format board | substrate. FIG. 7 is a cross-sectional view taken along line A-A ′ of the configuration of FIG. 6. It is a figure for demonstrating the modification of the 1st Embodiment of this invention. It is a figure which shows the typical example of the sensor head structure of the conventional reflective encoder. It is a figure for demonstrating the problem of the conventional reflective encoder. It is a figure for demonstrating the other problem of the conventional reflective encoder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Sensor head 2 Scale 3 Wiring board 4 Light source 5 Photo detector 6 Resin 7 Conductive member 8 Conductive wire 31 Ground electrode 51 Semiconductor IC
312 Front electrode 313 Extraction electrode 314 Back electrode

Claims (7)

A sensor head having one or more light sources and one or more photodetectors, and a scale movable relative to the sensor head, and detecting the light emitted from the light sources via the scale. An optical encoder that receives light from a sensor and outputs a displacement signal indicating a positional relationship between the sensor head and the scale from the sensor head,
The sensor head includes an electrode and a wiring board on which the light source and the photodetector are arranged at predetermined positions, a resin that covers the wiring board, the light source, and the photodetector. And
An optical encoder, wherein a first conductive member is disposed on at least a part of the surface of the resin.   The optical encoder according to claim 1, wherein the first conductive member transmits light from the light source.   The optical encoder according to claim 1, wherein the first conductive member is made of a metal oxide.   The optical encoder according to claim 1, wherein the electrode formed on the wiring board and the first conductive member are electrically connected by a second conductive member.   The optical encoder according to claim 4, wherein the second conductive member is disposed inside the resin of the sensor head.   2. The optical encoder according to claim 1, wherein the first conductive member is disposed over the entire surface of the resin.   2. The optical encoder according to claim 1, wherein a cleaning function material is disposed on at least a part of the first conductive member.

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