JP2021183950A - Multiple channel photoelectric sensor - Google Patents

Abstract

To provide a multiple channel photoelectric sensor that aligns the levels of noise in detection signals between channels.SOLUTION: A multiple channel photoelectric sensor comprises: a light receiving element group that includes a first light receiving element and a second light receiving element; an electromagnetism shielding member that blocks electromagnetic waves directed to the light receiving element group from the outside; a mounting substrate on which the light receiving element group is mounted; and a connection member that electrically connects GND wires of the mounting substrate and the electromagnetism shielding member with each other. On the mounting substrate, the wiring length of the first GND wire from an electrode connection point to which a negative electrode of the first light receiving element is connected to a member connection point to which the connection member is connected is equal to the wiring length of the second GND wire from an electrode connection point to which a negative electrode of the second light receiving element is connected to a member connection point to which the connection member is connected.SELECTED DRAWING: Figure 6

Description

The present invention relates to a multi-channel photoelectric sensor.

A fiber-type photoelectric sensor in which an optical fiber for light projection and an optical fiber for light reception are inserted and removed is known. The fiber-type photoelectric sensor detects whether or not the detection light projected onto the light projecting optical fiber is reflected by the detection target and returns to the light receiving optical fiber, or to what extent. This is a sensor that determines the presence or absence of a detection target and its distance. If the object to be detected is made of a translucent material, it is possible to detect the presence or absence of the object to be detected depending on whether the detected light is transmitted and the amount of light is attenuated. Among such photoelectric sensors, there is also a multi-channel photoelectric sensor capable of connecting a plurality of sets of optical fibers for light emission and reception (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2004-205209

As an application of the photoelectric sensor corresponding to a plurality of channels, it is assumed that a detection target having some common items such as the same object or the same type of object is detected in each channel. In such a case, if the noise level of the detection signal differs between the channels, the detection performance will vary between the channels, which may cause the user to misunderstand that it is a failure or cause adjustment work for each channel. , Another post-stage processing may be required to suppress variation.

The present invention has been made to solve such a problem, and provides a multi-channel photoelectric sensor in which the noise levels of detection signals are uniform among channels.

In the multi-channel photoelectric sensor according to one aspect of the present invention, a light receiving element group including a first light receiving element and a second light receiving element, an electromagnetic shielding member that blocks an electromagnetic wave directed from the outside to the light receiving element group, and a light receiving element group are mounted. The mounting board is provided with a connecting member for electrically connecting the GND wiring of the mounting board and the electromagnetic shielding member, and the connecting member is connected from the electrode connection point to which the negative electrode of the first light receiving element of the mounting board is connected. The wiring length of the first GND wiring to the connected member connection point is equal to the wiring length of the second GND wiring from the electrode connection point to which the negative electrode of the second light receiving element is connected to the member connection point to which the connection member is connected. According to the multi-channel photoelectric sensor configured in this way, the difference in the noise level of the detection signal that may occur between the channels can be reduced to a practically negligible level.

In the above-mentioned multi-channel photoelectric sensor, the connecting member may be configured to include a first connecting member corresponding to the first light receiving element and a second connecting member corresponding to the second light receiving element. With such a configuration, the degree of freedom in designing the mounting board can be improved.

Further, in the above-mentioned multi-channel photoelectric sensor, the electromagnetic shielding member may be a holding member formed of a conductive resin and holding a group of light receiving elements. With such a configuration, one element member can have a shielding function and a holding function, which contributes to miniaturization of the photoelectric sensor and simplification of the work process at low cost. At this time, the connecting member may be a fixture for fixing the mounting board to the holding member. If the fixture that physically fixes the mounting board and the holding member also serves as a connecting member that electrically connects the two, the soldering work can be omitted, which contributes to further simplification of the work process.

The above-mentioned multi-channel photoelectric sensor includes a light projecting element group including a first light emitting element corresponding to a first light receiving element and a second light emitting element corresponding to a second light receiving element, and the light emitting element group is described above. It is mounted on the mounting board, and the wiring length of the third GND wiring from the electrode connection point to which the negative electrode of the first light projecting element is connected to the member connection point to which the connecting member is connected, and the second throwing The wiring length of the fourth GND wiring from the electrode connection point to which the negative electrode of the optical element is connected to the member connection point to which the connection member is connected may be equal. With this configuration, the output levels can be made uniform between the channels in the floodlight system, so that the difference in the detection signals between the channels when the same object is detected can be reduced. In this case, each element may be linearly arranged in the order of the first light emitting element, the first light receiving element, the second light emitting element, and the second light receiving element. When the optical fibers corresponding to the respective elements are inserted and removed by the user, the arrangement is less likely to cause a misunderstanding by the user.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a multi-channel photoelectric sensor in which the noise level of the detection signal can be made uniform among the channels and the detection performance does not vary much.

It is an overall perspective view of the photoelectric sensor which concerns on this embodiment. It is an exploded perspective view which shows the main component of a photoelectric sensor. It is an exploded perspective view which shows the main component of a sensor unit. It is an overall perspective view of a sensor unit. It is the whole perspective view of the sensor unit from another viewpoint. It is a wiring diagram which shows typically the GND wiring of a sensor board. It is a wiring diagram which shows typically the GND wiring of the sensor board which concerns on a modification.

An embodiment of the present invention will be described with reference to the accompanying drawings. In each figure, those with the same reference numerals have the same or similar configurations. In addition, in each figure, when there are a plurality of structures having the same or similar structure, a reference numeral is added to a part thereof and the same reference numeral is omitted from the other parts in order to avoid complication. There is.

FIG. 1 is an overall perspective view of the photoelectric sensor 100 according to the present embodiment. The photoelectric sensor 100 according to the present embodiment is a two-channel optical fiber type photoelectric sensor including two pairs of input and output. Specifically, the photoelectric sensor of the first channel, which is detected via the first light receiving fiber 501 and the first light emitting fiber 502, and the second light receiving fiber 503 and the second light emitting fiber 504 are used. The input / output system of the second channel in which the detection is performed is provided.

In the first channel, whether or not the detected light projected onto the mounted first light emitting fiber 502 is reflected by the detection target and returned to the first light receiving fiber 502, or to what extent. By detecting, the presence or absence of the object to be detected and its distance are determined. If the object to be detected is made of a translucent material, it is possible to detect the presence or absence of the object to be detected depending on whether the detected light is transmitted and the amount of light is attenuated. Similarly, for the second channel, the presence / absence of the detection target and the distance thereof are determined using the second light receiving fiber 503 and the second light emitting fiber 504. The detection objects of the first channel and the second channel may be separate objects, or may be objects having some common items such as the same object and the same type of objects.

The photoelectric sensor 100 has a flat box shape as a whole, and mainly has a housing 190 and an opening / closing cover 110 that covers the upper portion of the housing 190 so as to be openable / closable. The housing 190 has four holes on the tip side. Specifically, the first lower insertion hole 191 for inserting and removing the first light receiving fiber 501, the first upper insertion hole 192 for inserting and removing the first light emitting fiber 502, and the second light receiving fiber 503 are inserted and removed. It has a second lower insertion hole 193 for inserting and removing a second lower insertion hole 193 and a second upper insertion hole 194 for inserting and removing a second light projecting fiber 504.

When the open / close cover 110 is opened, the user can operate the push button housed inside. Further, the opening / closing cover 110 is made of a transparent material, and the user can visually recognize the information presented by the display unit housed inside even when the opening / closing cover 110 is closed.

When the first channel is used, the first light receiving fiber 501 is inserted and fixed in the first lower insertion hole 191 and the first light emitting fiber 502 is inserted and fixed in the first upper insertion hole 192. Similarly, when the second channel is used, the second light receiving fiber 503 is inserted and fixed in the second lower insertion hole 193, and the second light emitting fiber 504 is inserted and fixed in the second upper insertion hole 194. NS. The photoelectric sensor 100 may have only one of the first channel and the second channel function, or both may function at the same time. However, the subsequent processing circuit, which is responsible for both the signal processing of the first channel and the signal processing of the second channel, sequentially executes the respective signal processing.

The housing 190 has a receiving portion of the connector unit 160 on the rear end side, and the figure shows a state in which the connector unit 160 is mounted on the receiving portion. The connector unit 160 is provided at one end of the cable 161 and connects the power supply line and the signal line included in the cable 161 to the circuit board inside the housing 190.

The x-axis, y-axis and z-axis are defined as shown in the figure. In the subsequent drawings, the same coordinate axes as those in FIG. 1 are also shown to indicate the orientation of the structure represented by each drawing. Further, in the following description, as described above, the z-axis positive direction is upward, the negative direction is downward, the x-axis negative side is the front end side, the positive side is the rear end side, and the z-axis positive side is the upper side. The negative side may be referred to as the lower side, the direction along the x-axis may be referred to as the longitudinal direction, the direction along the y-axis may be referred to as the lateral direction, and the direction along the z-axis may be referred to as the height direction.

FIG. 2 is an exploded perspective view showing the main components of the photoelectric sensor 100. The photoelectric sensor 100 is mainly composed of an open / close cover 110, a UI unit 200, a base frame 140, a sensor unit 150, a connector unit 160, a main board 170, a shield plate 180, and a housing 190. The housing 190 has an opening 195 on the upper side. That is, the internal space of the housing 190 is wide open upward. The UI unit 200, the base frame 140, the sensor unit 150, the main board 170, and the shield plate 180 are assembled and housed in the internal space of the housing 190 through the opening 195. The opening / closing cover 110 closes the opening 195. Further, the connector unit 160 is mounted from the rear end side of the housing 190.

The UI unit 200 is mainly composed of a mask sheet 121, a shading pad 122, a button pad 123, and a sub-board 130. The sub-board 130 is a rigid plate-shaped hard board, which is also called a rigid board.

The button pad 123 is a rubber molded sheet in which a key top and a base in contact with a mounting surface of a sub-board 130 are integrally formed. The shading pad 122 is a light-shielding plate arranged on the mounting surface of the sub-board 130, which is provided with a through hole corresponding to the information-presenting LED mounted on the sub-board 130 and the button pad 123. The mask sheet 121 is a sheet on which a transparent window frame that defines the outline of light from an LED for presenting information and characters and icons that explain the role of a push button are printed.

The base frame 140 forms the skeleton of the photoelectric sensor 100 and is molded of a thick resin so as not to be easily deformed. As shown in the figure, the base frame 140 has an L-shape as a whole, and serves as a base material on which the opening / closing cover 110, the UI unit 200, the sensor unit 150, the main board 170, and the shield plate 180 are attached.

The sensor unit 150 includes a fixing mechanism for fixing the inserted optical fiber to the sensor board on which the light emitting and receiving elements of each channel are mounted. Specifically, it will be described in detail later. The connector unit 160 connects the power line and the signal line included in the cable 161 to the corresponding terminals of the main board 170. The connector unit 160 may be configured to be detachable from the housing 190.

The main board 170 is a circuit board on which various elements that make the photoelectric sensor 100 function are mounted. The main board 170 is also a hard board like the sub board 130. The shield plate 180 is an electromagnetic shield plate that blocks electromagnetic waves from the outside toward the main substrate 170, and is formed by bending, for example, a copper plate. The shield plate 180 has a U-shape when observed from the longitudinal direction, and has an area that covers most of both mounting surfaces of the main substrate 170 by itself.

FIG. 3 is an exploded perspective view showing the main components of the sensor unit 150. The sensor unit 150 is mainly composed of a slider 210, a fiber gripper 220, a holder 230, a lever 240, a light emitting / receiving element group 250, a sensor substrate 260, and a connecting member 270.

The slider 210, the fiber gripper 220, and the lever 240 form a fixing mechanism for fixing the inserted optical fiber. The slider 210 is arranged on the tip end side of the holder 230. The lever 240 is attached to the upper part of the holder 230 via the hinge pin 241 so that the lever 240 can rotate within a certain angle range. Further, the lever 240 and the slider 210 are connected to each other via a link mechanism, and the slider 210 is displaced in the vertical direction according to the opening and closing of the lever 240. The fiber gripper 220 includes a first gripper 221 for fixing the first light receiving fiber 501 and the first light emitting fiber 502, and a second gripper 222 for fixing the second light receiving fiber 503 and the second light emitting fiber 504. include.

The holder 230 functions as a holding member for holding the light emitting / receiving element group 250. Specifically, the holder 230 has an fitting hole that matches the outer peripheral shape of each light receiving / receiving element, and each light receiving / receiving element is positioned and held in the holder 230 by being fitted into the fitting hole. The holder 230 is formed of a conductive resin in which a conductive filler is embedded, and the entire holder 230 is kept at the ground potential. Therefore, the holder 230 functions as an electromagnetic shielding member that blocks electromagnetic waves directed from the outside to the light emitting / receiving element group 250.

The light emitting / receiving element group 250 includes a first light receiving PD 251 and a first light emitting LED 252 constituting the first channel, and a second light receiving PD 253 and a second light emitting LED 254 forming the second channel. The detection light emitted from the first light emitting LED 252 is projected onto the detection object via the first light emitting fiber 502, and the detection light reflected by the detection target is the first light receiving fiber 501 via the first light receiving fiber 501. It is received by the light receiving PD251 and converted into an electric signal. The converted electric signal is transmitted to the processing circuit as a first detection signal. Similarly, the detection light emitted from the second light emitting LED 254 is projected onto the detection object via the second light emitting fiber 504, and the detection light reflected by the detection target is transmitted through the second light receiving fiber 503. The light is received by the second light receiving PD253 and converted into an electric signal. The converted electric signal is transmitted to the processing circuit as a second detection signal.

The first light-shielding plate 255 is a light-shielding plate that shields light leaking from the rear surface of the first light-emitting LED 252 from entering the first light-receiving PD251 and the second light-receiving PD253 as stray light, and penetrates the two electrode pins. It is attached to the first light receiving PD251. Similarly, the second light-shielding plate 256 is a light-shielding plate that shields light leaking from the rear surface of the second light-emitting LED 254 from entering the first light-receiving PD251 and the second light-receiving PD253 as stray light, and has two electrode pins. It penetrates and is attached to the second light receiving PD253.

The sensor board 260 is a mounting board on which the light emitting / receiving element group 250 is mounted, and is a hard board like the main board 170 and the sub board 130. Each of the light emitting and receiving element groups 250 is soldered to the mounting surface so that the light emitting portion or the light receiving portion protrudes from the sensor substrate toward the tip end side. The sensor board 260 includes a driver circuit that blinks the first floodlight LED 252 and the second floodlight LED 254 according to a control signal from a CPU (not shown). Further, it is equipped with a preamplifier circuit that amplifies the first detection signal and the second detection signal photoelectrically converted by the first light receiving PD251 and the second light receiving PD253. The sensor board 260 is electrically connected to the main board 170, and sends and receives control signals and detection signals to and from the main board 170.

The connecting member 270 is a fixture for fixing the sensor board 260 to the holder 230, and includes a first screw 271 and a second screw 272. The first screw 271 passes through the notch 261 provided in the sensor board 260 and is fastened to a prepared hole (not shown) provided in the holder 230. The second screw 272 passes through the through hole 262 provided in the sensor board 260 and is fastened to a prepared hole (not shown) provided in the holder 230. The first screw 271 and the second screw 272 are both highly conductive metal screws.

FIG. 4 is an overall perspective view of the sensor unit 150 in the assembled state. The first gripper 221 has a C ring portion 221a that sandwiches and fixes the tip portion of the first light receiving fiber 501, and a C ring portion 221b that sandwiches and fixes the tip portion of the first light emitting fiber 502. The second gripper 222 has a C ring portion 222a that sandwiches and fixes the tip portion of the second light receiving fiber 503, and a C ring portion 222b that sandwiches and fixes the tip portion of the second light emitting fiber 504. When the lever 240 is rotated from the open position to the lock position shown in the figure, the slider 210 slides downward with respect to the holder 230. At this time, the slider 210 pushes down the C ring portions 221a, 221b, 222a, and 222b to narrow the inner diameter. If an optical fiber is inserted through the C-ring portion, the optical fiber is pressed and fixed to the C-ring portion.

Specifically, the end face of the fixed first light receiving fiber 501 faces the first light receiving PD 251 and the end face of the similarly fixed first light emitting fiber 502 faces the first light emitting LED 252. Similarly, the end face of the fixed second light receiving fiber 503 faces the second light receiving PD 253, and the end face of the fixed second light emitting fiber 504 faces the second light emitting LED 254.

FIG. 5 is an overall perspective view of the sensor unit 150 from another viewpoint. The sensor board 260 is fixed to the rear end side of the holder 230 by the first screw 271 and the second screw 272. The two electrode pins of the positive electrode and the negative electrode in each of the light emitting and receiving element group 250 have their tips penetrating the sensor substrate 260 and are soldered to the corresponding lands. For example, focusing on each negative electrode pin, as shown in the figure, the negative electrode pin 251a of the first light receiving PD 251, the negative electrode pin 252a of the first light emitting LED 252, the negative electrode pin 253a of the second light receiving PD 253, and the second The negative electrode pins 254a of the floodlight LED 254 are arranged.

The photoelectric sensor 100 in the present embodiment includes a two-channel input / output system as described above, but the main use of such a photoelectric sensor is to use an object having some common property. It is expected to be detected in parallel on the channel. In such a case, if the noise level of the detection signal differs between the channels, the user may misunderstand that it is a failure, or post-processing based on the poorly performing channel may be required.

The difference in noise level between channels is caused by various elements of elements and circuits, and one of the main factors is the difference in GND wiring length in the circuit board. FIG. 6 is a wiring diagram schematically showing GND wiring provided on the sensor board 260 of the photoelectric sensor 100 according to the present embodiment.

The first PD negative electrode land 351 is a land (electrode connection point) to which the negative electrode pin 251a of the first light receiving PD 251 is soldered. Similarly, the second PD negative electrode land 353 is a land (electrode connection point) to which the negative electrode pin 253a of the second light receiving PD 253 is soldered.

On the other hand, a first screw land 371 as a screw member connection point is provided around the notch 261 through which the first screw 271 is inserted. When the first screw 271 is fastened to the holder 230 with the sensor substrate 260 interposed therebetween, the first screw land 371 comes into contact with the head of the first screw 271. Since the first screw 271 has a wider cross-sectional area and much smaller electrical resistance than the wiring of the sensor substrate 260, the first screw land 371 is a holder 230 shaped by a conductive resin via the first screw 271. It is kept substantially the same as the ground potential. Further, a second screw land 372 as a screw member connection point is provided around the through hole 262 through which the second screw 272 is inserted. The second screw land 372 comes into contact with the head of the second screw 272 when the second screw 272 is fastened to the holder 230 with the sensor substrate 260 interposed therebetween. Since the second screw 272 has a wider cross-sectional area and much smaller electrical resistance than the wiring of the sensor substrate 260, the second screw land 372 is a holder 230 shaped by a conductive resin via the second screw 272. It is kept substantially the same as the ground potential. That is, the first screw land 371 and the second screw land 372 are both maintained at the ground potential when the sensor substrate 260 is fixed to the holder 230 by the first screw 271 and the second screw 272.

The first GND wiring 311 is a GND wiring that connects the first PD negative electrode land 351 and the first screw land 371. The second GND wiring 312 is a GND wiring that connects the second PD negative electrode land 353 and the second screw land 372. In the present embodiment, the wiring length of the first GND wiring 311 and the wiring length of the second GND wiring 312 are set to be equal to each other. As described above, since the first screw land 371 and the second screw land 372 have substantially the same potential, by aligning the wiring lengths thereof, the noise level difference between the first detection signal and the second detection signal can be practically obtained. It is reduced to a negligible level.

The first LED negative electrode land 352 is a land (electrode connection point) to which the negative electrode pin 252a of the first floodlight LED 252 is soldered. Similarly, the second LED negative electrode land 354 is a land (electrode connection point) to which the negative electrode pin 254a of the second floodlight LED 254 is soldered.

The third GND wiring 313 is a GND wiring that connects the first LED negative electrode land 352 and the first screw land 371. Further, the 4th GND wiring 314 is a GND wiring connecting the 2nd LED negative electrode land 354 and the 2nd screw land 372. In the present embodiment, the wiring length of the third GND wiring 313 and the wiring length of the fourth GND wiring 314 are set to be equal to each other. As described above, since the first screw land 371 and the second screw land 372 have substantially the same potential, by aligning these wiring lengths, the variation in the output level of each detected light due to the difference in the wiring length can be obtained. It is being reduced. As a result, the difference between the first detection signal and the second detection signal when the same object is detected is reduced.

The GND wiring shown is schematically an example, and the specific wiring pattern is not limited to the illustrated example. If a multilayer board is adopted as the sensor board 260, the GND wiring may be provided in an intermediate layer or may be provided across a plurality of layers. Further, since the GND wiring provided on the same substrate is generally realized with the same width and conductive material, the explanation was given focusing on the wiring length, but when the width and the conductive material are different between the GND wirings. The impedance of each GND wiring may be adjusted to be equal to each other.

In the present embodiment described above, as a connecting member for electrically connecting to the holder 230, a first screw 271 corresponding to the first light receiving PD 251 and a second screw 272 corresponding to the second light receiving PD 253 are used, respectively. Provided. With this configuration, the degree of freedom in designing the mounting board is improved. As one of the benefits, a linear arrangement is realized in the order of the first light receiving PD 251, the first light emitting LED 252, the second light receiving PD 253, and the second light emitting LED 254 from the lower side to the upper side. Due to such an arrangement, the light receiving system is on the lower side and the light projecting system is on the upper side in each channel. Very preferable.

However, the screws as a connecting member for electrically connecting to the holder 230 can be combined into one. FIG. 7 is a wiring diagram schematically showing the GND wiring of the sensor board 260'according to the modified example. The sensor board 260'is different from the sensor board 260 in that it is first electrically connected to the holder 230 only by the first screw 271.

Therefore, the negative electrode pin 251a of the first light receiving PD251, the negative electrode pin 252a of the first light emitting LED 252, the negative electrode pin 253a of the second light receiving PD253, and the negative electrode pin 254a of the second light receiving LED 254 are all electrically with the first screw land 371. Need to be connected. Therefore, in this modification, the arrangement of the first light receiving PD 251 and the first light emitting LED 252 is left as it is, and the arrangement of the second light receiving PD 253 and the second light emitting LED 254 is replaced. That is, focusing on each negative electrode pin, from the bottom to the top, the negative electrode pin 251a of the first light receiving PD251, the negative electrode pin 252a of the first light emitting LED 252, the negative electrode pin 254a of the second light receiving LED 254, and the second light receiving PD253. The negative electrode pins 253a are arranged. The first PD negative electrode land 351 and the first LED negative electrode land 352, the second LED negative electrode land 354', and the second PD negative electrode land 353'are provided on the sensor substrate 260' from the bottom to the top corresponding to these negative electrode pins. ..

By adopting such an arrangement, the wiring length of the first GND wiring 311 connecting the first PD negative electrode land 351 and the first screw land 371 and the second GND wiring 312 connecting the second PD negative electrode land 353'and the first screw land 371 are used. 'The wiring lengths are equal. Similarly, the length of the wiring length of the third GND wiring 313 connecting the first LED negative electrode land 352 and the first screw land 371 and the wiring length of the fourth GND wiring 314' connecting the second LED negative electrode land 354'and the first screw land 371. Are equal. The 3rd GND wiring 313 and the 4th GND wiring 314'are partially shared. As described above, the corresponding GND wiring may be wiring that shares a part with each other.

If such a sensor board 260'is adopted, it contributes to the reduction of the number of parts and the simplification of the work process. In both the wiring example of the sensor board 260 and the wiring example of the sensor board 260'described above, the wiring length of the third wiring and the wiring length of the fourth wiring are equal to each other, but at least the wiring length of the first wiring is the same. It does not matter if the wiring lengths of the second wirings are equal to each other. If the wiring length of the first wiring and the wiring length of the second wiring are equal to each other, the noise level of the detection signal will be uniform between the channels to some extent. No processing is required.

Further, in the present embodiment described above, the holder 230 holding the light emitting / receiving element group 250 is shaped with a conductive resin to provide an electromagnetic shielding member that blocks electromagnetic waves from the outside toward the light receiving / receiving element group 250. With such a configuration, one element member can have a shielding function and a holding function, which contributes to miniaturization of the photoelectric sensor 100 and simplification of the work process. However, for example, if the shield plate 180 is configured to wrap the sensor unit 150 as well, the shield plate 180 can be an electromagnetic shielding member that blocks electromagnetic waves directed from the outside to the light emitting / receiving element group 250. In this case, the holder 230 does not have to be a conductive resin, and the GND wiring of the sensor substrate 260 may be connected to the shield plate 180 via the connecting member.

Further, in the present embodiment described above, the screw is adopted as the connecting member, but the connecting member is not limited to the screw. Any fixture made of a conductive material may be used. If the fixture that physically fixes the sensor board 260, which is the mounting board, and the holder 230, which is the holding member, also serves as a connecting member that electrically connects the two, soldering work can be omitted, and the work process can be further enhanced. Contributes to simplification. Further, for example, the metal section provided on the holder 230 and the connection land of the sensor substrate 260 may be directly connected by soldering. In this case, the metal section provided on the holder 230 and the solder serve as a connecting member. The fixing member may be prepared separately as a fixing member and the connecting member may be prepared separately as a connecting member. In particular, when solder is used as the connecting member, a fixing member may be prepared separately.

Further, although the photoelectric sensor 100 in the present embodiment described above is provided with an input / output system having two channels, it may be provided with an input / output system having a larger number of channels. When three or more input / output systems are provided, even if the GND wiring lengths from the electrode lands to which the negative electrodes of the light receiving PDs are connected to the member lands to which the connecting members are connected are all set to be equal. Often, some of them may be set to be equal. For example, if an input / output system of 3 channels is provided, 2 of which are for short-distance detection and the remaining 1 channel is for long-distance detection, the GND wiring length is longer than that of 2 channels for short-distance detection. It may be set to be equal.

[Appendix 1]
A group of light receiving elements including a first light receiving element (251) and a second light receiving element (253),
An electromagnetic shielding member (230) that blocks electromagnetic waves from the outside toward the light receiving element group, and
A mounting board (260) on which the light receiving element group is mounted and
A connection member (271, 272) for electrically connecting the GND wiring (311, 312) of the mounting board (260) and the electromagnetic shielding member (230) is provided.
From the electrode connection point (351) to which the negative electrode (251a) of the first light receiving element (251) of the mounting substrate (260) is connected to the member connection point (371) to which the connection member (271) is connected. From the electrode connection point (353) to which the wiring length of the first GND wiring (311) and the negative electrode (253a) of the second light receiving element (253) are connected, the member connection point to which the connection member (272) is connected. A multi-channel photoelectric sensor (100) having the same wiring length of the second GND wiring (312) up to (372).

100 ... photoelectric sensor, 110 ... Open / close cover, 121 ... Mask sheet, 122 ... Shading pad, 123 ... Button pad, 130 ... Sub board, 140 ... Base frame, 150 ... Sensor unit, 160 ... Connector unit, 161 ... Cable, 170 ... main board, 180 ... shield plate, 190 ... housing, 191 ... first lower insertion hole, 192 ... first upper insertion hole, 193 ... second lower insertion hole, 194 ... second upper insertion hole, 195 ... opening , 200 ... UI unit, 210 ... slider, 220 ... fiber gripper, 221 ... first gripper, 221a, 221b ... C ring part, 222 ... second gripper, 222a, 222b ... C ring part, 230 ... holder, 240 ... lever , 241 ... hinge pin, 250 ... light emitting / receiving element group, 251 ... first light receiving PD, 251a ... negative electrode pin, 252 ... first light emitting LED, 252a ... negative electrode pin, 253 ... second light receiving PD, 253a ... negative electrode pin, 254. ... 2nd light emitting LED, 254a ... Negative electrode pin, 255 ... 1st shading plate, 256 ... 2nd shading plate, 260, 260'... Sensor board, 261 ... Notch, 262 ... Through hole, 270 ... Connecting member, 271 ... 1st screw, 272 ... 2nd screw, 311 ... 1st GND wiring, 312, 312'... 2nd GND wiring, 313 ... 3rd GND wiring, 314, 314' ... 4th GND wiring, 351 ... 1st PD negative electrode land, 352 ... 1st LED negative electrode land, 353, 353'... 2nd PD negative electrode land, 354, 354'... 2nd LED negative electrode land, 371 ... 1st screw land, 372 ... 2nd screw land, 501 ... 1st light receiving fiber, 502 ... 1st throw Optical fiber, 503 ... Second light receiving fiber, 504 ... Second light emitting fiber

Claims (6)

A group of light receiving elements including a first light receiving element and a second light receiving element,
An electromagnetic shielding member that blocks electromagnetic waves from the outside toward the light receiving element group,
The mounting board on which the light receiving element group is mounted and
A connection member for electrically connecting the GND wiring of the mounting board and the electromagnetic shielding member is provided.
The wiring length of the first GND wiring from the electrode connection point to which the negative electrode of the first light receiving element is connected to the member connection point to which the connection member is connected on the mounting substrate, and the negative electrode of the second light receiving element are A multi-channel photoelectric sensor having the same wiring length of the second GND wiring from the connected electrode connection point to the member connection point to which the connection member is connected. The multi-channel photoelectric sensor according to claim 1, wherein the connecting member includes a first connecting member corresponding to the first light receiving element and a second connecting member corresponding to the second light receiving element. The multi-channel photoelectric sensor according to claim 1 or 2, wherein the electromagnetic shielding member is a holding member formed of a conductive resin and holding the light receiving element group. The multi-channel photoelectric sensor according to claim 3, wherein the connecting member is a fixture for fixing the mounting board to the holding member. A group of light emitting elements including a first light emitting element corresponding to the first light receiving element and a second light emitting element corresponding to the second light receiving element is provided.
The light projecting element group is mounted on the mounting board, and the light projecting element group is mounted on the mounting board.
The wiring length of the third GND wiring from the electrode connection point to which the negative electrode of the first floodlight element is connected to the member connection point to which the connection member is connected on the mounting board, and the negative of the second floodlight element. The multi-channel photoelectric sensor according to any one of claims 1 to 4, wherein the wiring lengths of the fourth GND wiring from the electrode connection point to which the electrodes are connected to the member connection point to which the connection member is connected are the same. The multi-channel photoelectric sensor according to claim 5, wherein the first light emitting element, the first light receiving element, the second light emitting element, and the second light receiving element are linearly arranged in this order.

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