JPH0528988U - Photoelectric detector - Google Patents

Abstract

(57) [Abstract] [Purpose] To obtain a photoelectric detection device in which a plurality of photoelectric switches sequentially operate. A photoelectric switch 31 has an auxiliary core 43 provided on one side wall 33a of a case 33, and a receiving means 38 for receiving a pulsed magnetic signal, and another side wall 33b of the case 33. It has another auxiliary core 46 and an exciting means 39 for outputting a pulsed magnetic signal, and these receiving means 38, exciting means 39 and auxiliary cores 43 and 46 are arranged on the same axis L1. Characterize. [Effect] Mutual interference between photoelectric switches can be reliably prevented, and the transmission efficiency of timing signals can be improved.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a photoelectric detection device in which a plurality of photoelectric switches that sequentially determine the presence or absence of an object by projecting light and detecting the presence or absence of reflected light are arranged.

[0002]

[Prior Art]

 A photoelectric switch is known as a means for detecting the presence or absence of a moving object on a conveyor line or the like. This is to determine the presence / absence of an object by projecting light on the path of the object and detecting the presence / absence of reflected light from the moving object. In such a photoelectric switch, in order to reduce power consumption and prevent mutual interference, the projection light is pulsed and projected intermittently.

FIG. 7 is an exploded perspective view showing an example of a conventional photoelectric switch of this type. This photoelectric switch is of a so-called optical fiber type, and is mainly composed of a main body 1 and a detection unit 2. Is becoming The main body 1 includes a case 3, a circuit board 5 built in the case 3, to which wirings 4 such as a power cable and an output cable are connected, and a light projecting element 6 and a light receiving element 7 provided on the circuit board 5. , A top plate 10 which covers the upper part of the case 3 and to which the indicator lamp 8 and the adjusting knob 9 are attached, and insertion holes 11 and 12 which are attached to the side surfaces of the case 3 and which face the light projecting element 6 and the light receiving element 7. It has a connecting part 13 which has. On the other hand, the detection unit 2 has a detection head 15 arranged to face the object to be detected 14, one end of which is connected to the detection head 15, and the other end of which is provided with the light projecting element 6 through the insertion holes 11 and 12. It is composed of a pair of optical fibers 16 connected to the light receiving element 7. In such a conventional photoelectric switch, when sensing light is intermittently output from the light projecting element 6 in response to a timing signal of a predetermined cycle, the sensing light is guided through the optical fiber 16 and is detected by the detection head 15. The detection object 14 is projected. At this time, when the light reflected by the object to be detected 14 enters the detection head 15, the reflected light is guided through the optical fiber 16 and is received by the light receiving element 7, and along with this light reception, the wiring 4 from the circuit board 5 The detection signal is output via. On the other hand, when there is no detected object 14, the detection signal is not output from the circuit board 5 because the reflected light is not received by the light receiving element 7.

FIG. 8 is an exploded perspective view showing another example of the conventional photoelectric switch. This photoelectric switch is so-called a lens type, and is the optical fiber type shown in FIG. 7 described above. Compared with the above, the detection unit is mainly different, and the pulsed light output from the light projecting element 17 is projected onto the object 14 to be detected through the light projecting lens 18, and the reflected light reflected by the object 14 is received by the light receiving lens. A light receiving element 20 receives light via 19.

And, usually, not only one photoelectric switch but a plurality of photoelectric switches are used to detect the presence or absence of an object. For example, in a conveyor line, multiple photoelectric switches are installed at one location, such as a photoelectric switch that projects light from the lateral direction, a photoelectric switch that projects light from below, and a photoelectric switch that projects light from above. We are trying to make it more accurate (hereinafter, this projected light is called sensing light). However, when multiple photoelectric switches are arranged close to or close to each other in this way and each photoelectric switch continuously emits light, each photoelectric switch also receives the sensing light projected by the other photoelectric switches. There is a risk. This is called mutual interference as described above.In a photoelectric switch, light is emitted intermittently so that the light emission timing does not overlap with other photoelectric switches, and the light reflected by itself and the light emitted from other photoelectric switches are also used. A means for distinguishing the received light (interference light) is provided.

FIG. 9 is a block diagram showing a conventional photoelectric switch, in which 21 is a periodic pulse generating circuit, 22 is a light projecting unit, 23 is a light receiving unit, 24 is a gate circuit, 25 is an integrating circuit, 26 Is a decision circuit. For example, the pulse generation circuit 21, the gate circuit 24, the integration circuit 25, and the determination circuit 26 are provided on the circuit board 5, the light projecting unit 22 includes the light projecting element 6, and the light receiving unit 23 includes the light receiving element. It consists of 7 etc.

In FIG. 9, the periodic pulse generating circuit 21 constantly generates a pulse P1 having a constant period, and the light projecting section 22 is driven by this pulse P1 and has a pulse shape with the same period and duty ratio as this pulse P1. Project sensing light to. When this sensing light is reflected by an object (not shown), the reflected light is received by the light receiving section 23, and the pulse P2 is output. This pulse P2 has the same timing as the pulse P1 if it is obtained by the reflected light accompanying the projection of its own light projecting section 22, but it is obtained by receiving the sensing light from another photoelectric switch. If so, the pulse P1 and the timing do not match. Therefore, the output pulse P2 of the light receiving section 23 is supplied to the gate circuit 24 which uses the pulse P1 as a gate pulse, and extracts only the pulse generated by its own projection from the pulse P2. The output pulse of the gate circuit 24 is taken in at the timing of the pulse P1 by the integrating circuit 25, and when the integrated value is equal to or greater than the preset threshold value, the determining circuit 26 determines that there is an object.

The sensing light projected from the light projecting unit 22 onto the object is reflected by the object, but the reflected light from the object is scattered and a part of the reflected light is received by the light receiving unit 23. Therefore, the amount of light received by the light receiving unit 23 is small. Therefore, although the pulse P2 is generated from a small amount of light, if the presence or absence of an object is determined for each such pulse P2, the detection accuracy of the presence or absence becomes low. For this purpose, an integrating circuit 25 is provided so that the pulse extracted by the gate circuit 24 is integrated and a determination is made according to the magnitude of the integrated value. The integrating circuit 25 may be an analog integrating circuit, but normally a pulse counter is used, and the judgment circuit 26 has an object with the count value when, for example, eight pulses at the timing of the pulse P1 are continuously supplied from the gate circuit 24. I will judge it.

In such a photoelectric switch, if the duty ratio of the output pulse P 1 of the periodic pulse generation circuit 21 is made sufficiently smaller than the cycle, the probability of mutual interference is reduced and the power consumption is also reduced. However, each photoelectric switch is completely independent, and usually the period of light projection of each photoelectric switch is almost the same. For this reason, the light emission timings may be overlapped by two or more photoelectric switches. In such a case, in FIG. 9, the pulse P2 whose timing coincides with the pulse P1 is output from the light receiving unit 23 because the other photoelectric switch emits light, even though there is no object. The pulse P2 cannot be removed by the gate circuit 24, and therefore an error will occur in the determination of the presence / absence of an object.

An example of a technique for preventing such mutual interference is disclosed in Japanese Patent Publication No. 60-51043. This is because, as shown in FIG. 10, the interference discrimination circuit 27 discriminates whether or not the output pulse of the gate circuit 24 is due to the interference light, and when it is due to the interference light, a pulse is generated by the transfer circuit 28. The circuit 21a is controlled to advance or delay the phase of the pulse P1 to be generated.

Further, in Japanese Patent Laid-Open No. 61-138192, a pulse signal generated by receiving interference light is extracted, a pulse having the same frequency as the pulse signal but a different phase is generated, and the light projecting unit is driven. A technique is disclosed in which the light is projected with the same frequency as the interference light but with a different phase.

Further, in Japanese Patent Laid-Open No. 63-263917, when a pulse that coincides with the light emission timing is obtained from the light receiving unit, the light emission period is sequentially shifted from the reference period, and a predetermined number of such pulses are obtained. A technique is disclosed in which the projection cycle is returned to the original reference cycle. According to this, when the light emission timing of another photoelectric switch whose light emission cycle is almost the same as that of the self coincides with the light emission timing of the self, the light receiving unit obtains a pulse that coincides with the light emission timing. The light emission cycle of is gradually changed. On the other hand, the light projecting periods of other photoelectric switches do not change. Therefore, the light emitting timing of itself deviates from the light emitting timing of the other photoelectric switch, and the pulse from the light receiving portion due to the light from the other photoelectric switch is removed by the gate circuit. However, the light-receiving unit receives the light emitted by itself from the light-receiving unit, and the output pulse of the light-receiving unit thereby coincides with its own light-projection timing. When the predetermined number of such pulses are obtained, the self-projection cycle returns to the original reference cycle. However, the self-projection timing at this time is deviated from the previous projection timing due to the above operation, and thus is deviated from the projection timing of the other photoelectric switch.

[0013]

[Problems to be solved by the device]

 All of the above-mentioned conventional techniques attempt to prevent mutual interference with other photoelectric switches by shifting the projection timing, and when the number of photoelectric switches installed in one location is small. Is quite effective. However, when a large number of photoelectric switches are installed side by side at one location, the emission timings of these photoelectric switches must be different in order to eliminate mutual interference, so at least the emission of these photoelectric switches must be different. The difference in optical timing is subtle. For this reason, if the light emitting timings of two photoelectric switches coincide with each other and the light emitting timings of those two photoelectric switches are shifted, the light emitting timings of the other photoelectric switches coincide with each other, and mutual interference is completely prevented. I can't.

Further, if each of the photoelectric switches is provided with the mutual interference preventing means as described above, the light projecting timings of all of the plurality of photoelectric switches in which mutual interference has occurred are shifted. In this case, in order to eliminate mutual interference due to these shifts, it is extremely difficult to determine the shift amount and shift direction of the projection timing that are unique to each photoelectric switch. Becomes

Further, the above-mentioned conventional technique requires mutual interference preventing means having a complicated circuit configuration.

An object of the present invention is to provide a photoelectric detection device capable of sequentially operating a plurality of photoelectric switches provided in one place.

[0017]

[Means for Solving the Problems]

 In order to achieve the above object, a light projecting element that projects sensing light intermittently according to a timing signal of a predetermined cycle, a light receiving element that receives reflected light reflected by an object to be detected, and these light projecting elements. A plurality of photoelectric switches that determine the presence or absence of an object based on the presence or absence of an optical pulse whose timing coincides with that of the sensing light are arranged in close proximity or in close contact with each other. In the photoelectric detection device, the photoelectric switch is provided on one side of the photoelectric switch, and receives means for receiving a pulse-shaped magnetic signal, and a synchronization means for synchronizing the magnetic signal based on the magnetic signal. Signal generating means for generating a timing signal or a delayed timing signal delayed for a predetermined time from the magnetic signal and outputting the delayed timing signal to the light projecting element, and the other side portion of the photoelectric switch. And an exciting means for outputting a pulsed magnetic signal to the outside in synchronization with the synchronization timing signal or the delay timing signal, and the side wall is provided on at least one of the receiving means and the exciting means. In addition to the above, the receiving means, the exciting means and the auxiliary core are arranged on the same axis parallel to the arrangement direction of the photoelectric switch, and the exciting means of the preceding photoelectric switch is connected via the auxiliary core. The magnetic signal is transmitted to the receiving means of the photoelectric switch in the next stage.

[0018]

[Action]

 According to the present invention, as described above, the receiving means and the exciting means are arranged on one side and the other side of each photoelectric switch, respectively, and both the receiving means and the exciting means are provided on the side wall of the case. Since it has an auxiliary core, and these receiving means, exciting means and auxiliary core are arranged on the same axis parallel to the arrangement direction of the photoelectric switches, when a plurality of photoelectric switches are installed side by side, When a pulse-shaped magnetic signal is output from the exciting means of the photoelectric switch, the photoelectric switch at the next stage receives the magnetic signal by the receiving means, and based on this magnetic signal, the signal generating means causes the synchronous timing signal or delay. A timing signal is generated and output to the light projecting element. Therefore, the light projecting element intermittently projects the sensing light according to the synchronous timing signal or the delayed timing signal, and the reflected light reflected by the object to be detected is received by the light receiving element, and the sensing light and the timing are received. The presence / absence of an object is determined by the presence / absence of reception of an optical pulse in which With this, it is possible to sequentially operate a plurality of photoelectric switches provided in one place. In addition, since the auxiliary cores provided on the side walls of the two cases adjacent to each other are extremely close to each other and exactly face each other, the magnetic signal output from one exciting means is efficiently received by the other receiving means. Can receive.

[0019]

【Example】

 An embodiment of the photoelectric detection device of the present invention will be described below with reference to the drawings.

FIG. 1 is an exploded perspective view of a photoelectric switch provided in a first embodiment of the photoelectric detection device of the present invention, FIG. 2 is a cross-sectional view of the photoelectric switch of FIG. 1, and FIG. 3 is the photoelectric detection device of FIG. FIG. 3 is a perspective view showing the arrangement state of FIG.

In the photoelectric detection device of this embodiment shown in FIG. 3, the photoelectric switch 31 and the photoelectric switch 32 of the next stage screwed to the photoelectric switch 31 are closely arranged. As shown in FIG. 1, the photoelectric switch 31 is formed in a rectangular parallelepiped shape, and has a case 33 having an opening, and a pair of light sources respectively connected to a light emitting element and a light receiving element (not shown) built in the case 33. The fibers 34 and 35, the upper plate 36 attached to the upper end of the case 33, and a signal generation means (not shown) which is built in the case 33 and generates a synchronization timing signal or a delay timing signal and outputs it to the light projecting element are provided. A circuit board 37, a receiving means 38 of FIG. 2 which is arranged on one side of the photoelectric switch 31 and receives a pulsed magnetic signal, and a receiving means 38 of the other side of the photoelectric switch 31, Exciting means 39 for outputting a pulse-shaped magnetic signal to the outside in synchronization with the synchronization timing signal or the delay timing signal.

The receiving means 38 is attached to one side surface of the circuit board 37 and is located inside the one side wall 33 a of the case 33. The core 41 is made of a magnetic material, and the receiving coil 42 is wound around the core 41. And an auxiliary core 43 that is integrally molded with the case 33 and that has an end surface that is substantially the same as the outer surface of the one side wall 33a. Similarly, the excitation step 39 is attached to the other side surface of the circuit board 37 and is located inside the other side wall 33b of the case 33. The magnetic core 44 and the transmitter coil 45 wound around the core 44 are also provided. And an auxiliary core 46 which is integrally molded with the case 33 and has an end surface that is substantially the same as the outer surface of the other side wall 33b. As shown in FIG. 1, the auxiliary core 46 is composed of a cylindrical core 47 and a ring-shaped core 48 positioned around the cylindrical core 47, and the other auxiliary cores 43 are also the same. The receiving means 38, the exciting means 39, and the auxiliary cores 43 and 46 are arranged on the same axis L1 parallel to the arrangement direction of the photoelectric switches 31 and 32.

Similarly, the photoelectric switch 32 in the next stage has, as shown in FIG. 3, an auxiliary core 49 and the like arranged on the axis L1. These photoelectric switches 31 and 32 are connected to each other via a screw 50 in a state of being closely arranged to each other.

In the first embodiment, when the pulsed magnetic signal is transmitted to the photoelectric switch 31, the photoelectric switch 31 receives the magnetic signal by the receiving means 38, and the pulse generating circuit Outputs a synchronization timing signal synchronized with the magnetic signal or a delay timing signal delayed by a predetermined time from the magnetic signal, and the sensing light intermittently responds to the optical fiber 34 and the delay timing signal in accordance with the synchronization timing signal or the delay timing signal. Light is projected through the detection head. At this time, the reflected light reflected by the object to be detected is received through the detection head and the optical fiber 35, and the presence or absence of the object is determined by the presence or absence of the light pulse whose timing coincides with the sensing light. When the exciting means 39 outputs a magnetic signal in synchronism with the synchronous timing signal or the delayed timing signal, the photoelectric switch 32 at the next stage receives it by the receiving means and determines the presence or absence of an object according to the magnetic signal. It is like this.

In the first embodiment configured as described above, it is possible to sequentially operate the plurality of photoelectric switches 31, 32 provided in one place. The exciting step 39 of the photoelectric switch 31 has auxiliary cores 46 embedded in the side walls 33b of the case 33. Similarly, the receiving means of the photoelectric switch 32 in the next stage is also embedded in the side wall of the case. Since the exciting means 39 of the photoelectric switch 31 and the receiving means of the photoelectric switch 32 in the next stage are arranged on the same axis L1 parallel to the arrangement direction of the photoelectric switches 31, 32, The auxiliary core 46 of the means 39 and the auxiliary core of the receiving means are very close to each other and exactly face each other. Therefore, the magnetic coupling between the transmitting coil 45 of the photoelectric switch 31 and the receiving coil of the photoelectric switch 32 becomes very close, and most of the magnetic flux generated in the transmitting coil 45 passes through the receiving coil. Therefore, the magnetic signal generated in the transmission coil 45 by the synchronization timing signal or the delay timing signal is efficiently taken in by the reception coil of the photoelectric switch 32, and the high transmission efficiency of the synchronization timing signal or the delay timing signal is obtained.

In the present embodiment, the case where the optical fiber type photoelectric switch having the optical fibers 34 and 35 is provided is illustrated, but the present invention is not limited to this, and a plurality of lens type photoelectric switches are provided. Even when they are provided side by side, the photoelectric switches can be sequentially operated in the same manner. Further, in the present embodiment, the case of the photoelectric detection device including the two photoelectric switches 31 and 32 is illustrated, but the present invention is not limited to this, and the photoelectric detection device including three or more photoelectric switches is provided in one place. Even when installed side by side, these photoelectric switches can be operated sequentially. Further, in this embodiment, both the receiving means 38 and the exciting means 39 are provided with the auxiliary cores 43 and 46, respectively, but it is also possible to provide only one of them with the auxiliary cores if necessary.

FIG. 4 is an exploded perspective view of a photoelectric switch provided in a second embodiment of the photoelectric detection device of the present invention, FIG. 5 is a cross-sectional view of the photoelectric switch of FIG. 4, and FIG. 6 is a photoelectric detection device of FIG. FIG. 3 is a perspective view showing the arrangement state of FIG. 4 to 6, the same parts as those shown in FIGS. 1 to 3 described above are designated by the same reference numerals. That is, 34 and 35 are optical fibers, 36 is a top plate, 37 is a circuit board, and 50 is a screw.

In the photoelectric detection device of the present embodiment shown in FIG. 6, the photoelectric switch 51 and the photoelectric switch 52 of the next stage screwed to the photoelectric switch 51 are provided in the same manner as the first embodiment described above. They are closely arranged. The photoelectric switch 51 is formed in a rectangular parallelepiped shape, has a case 53 having an opening, and a receiving unit 54 of FIG. 5 arranged on one side of the photoelectric switch 51 for receiving a pulsed magnetic signal. It is provided on the other side of the photoelectric switch 51 and has an excitation means 55 for outputting a pulsed magnetic signal to the outside.

The receiving means 54 is attached to one side surface of the circuit board 37, and is provided with a magnetic core 61 located inside one side wall 53 a of the case 53, and a receiving coil 62 wound around the core 61. And an auxiliary core 63 provided on the one side wall 53a. The exciting means 55 is attached to the other side surface of the circuit board 37 and is located inside the other side wall 53b of the case 53, and has a magnetic core 64, and a transmitting coil 65 wound around the core 64. , And an auxiliary core 66 provided on the other side wall 53b. As shown in FIG. 4, the auxiliary core 66 is press-fitted into a hole 67 penetrating the side wall 53b and has an end surface that is substantially the same as the outer surface of the side wall 53b, and the other auxiliary cores 63 are also the same. The receiving means 54, the exciting means 55, and the auxiliary cores 63 and 66 are arranged on the same axis L2 parallel to the arrangement direction of the photoelectric switches 51 and 52.

Similarly, the photoelectric switch 52 at the next stage has an auxiliary core 68 and the like arranged on the axis L2, as shown in FIG. These photoelectric switches 51 and 52 are connected to each other via a screw 50 in a state in which they are closely arranged.

Also in the second embodiment, when the pulsed magnetic signal is transmitted to the photoelectric switch 51, the photoelectric switch 51 receives the magnetic signal by the receiving means 54, and the pulse generating circuit. Output a synchronization timing signal synchronized with the magnetic signal or a delay timing signal delayed by a predetermined time from the magnetic signal, and intermittently sense light according to the synchronization timing signal or the delay timing signal. Light is emitted through the detection head. At this time, the reflected light reflected by the object to be detected is received via the detection head and the optical fiber 35, and the presence or absence of the object is determined by the presence or absence of the light pulse whose timing coincides with the sensing light. Further, when the exciting means 55 outputs a magnetic signal in synchronization with the synchronous timing signal or the delayed timing signal, the photoelectric switch 52 at the next stage receives it by the receiving means and determines the presence or absence of an object according to the magnetic signal. It is like this.

Also in the second embodiment configured as described above, it is possible to obtain the same effect as that of the first embodiment described above. In addition, in the present embodiment, the case where the optical fiber type photoelectric switch having the optical fibers 34 and 35 is provided side by side is illustrated, but the present invention is not limited to this, and a plurality of lens type photoelectric switches are provided side by side. Also in this case, the photoelectric switches can be sequentially operated in the same manner. Furthermore, the case of the photoelectric detection device including the two photoelectric switches 51 and 52 has been illustrated, but the present invention is not limited to this, and even when a photoelectric detection device including three or more photoelectric switches is provided in one place, These photoelectric switches can be activated sequentially. Further, in the present embodiment, both the receiving means 54 and the exciting means 55 are provided with the auxiliary cores 63 and 66, respectively, but it is possible to provide only one of the auxiliary cores 63 and 66 as required.

[0033]

[Effect of the device]

 Since the present invention is configured as described above, it is possible to sequentially operate a plurality of photoelectric switches provided in one place by transmitting a pulsed magnetic signal, and therefore a mutual interference preventing means having a complicated circuit configuration is required. Therefore, it is possible to reliably prevent mutual interference of the projection timing between the photoelectric switches. In addition, as described above, between a plurality of photoelectric switches installed side by side, the auxiliary cores provided on the side walls of the two cases that are adjacent to each other are extremely close and accurately face each other. High transmission efficiency by magnetic signals can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of a photoelectric switch included in a first embodiment of a photoelectric detection device of the present invention.

2 is a cross-sectional view of the photoelectric switch of FIG.

FIG. 3 is a perspective view showing an arrangement state of the photoelectric detection devices of FIG.

FIG. 4 is an exploded perspective view of a photoelectric switch provided in a second embodiment of the photoelectric detection device of the present invention.

5 is a cross-sectional view of the photoelectric switch of FIG.

FIG. 6 is a perspective view showing an arrangement state of the photoelectric detection devices of FIG.

FIG. 7 is an exploded perspective view showing a conventional example of an optical fiber type photoelectric switch.

FIG. 8 is an exploded perspective view showing a conventional example of a lens-type photoelectric switch.

FIG. 9 is a block diagram illustrating an operation of a conventional photoelectric switch.

FIG. 10 is a block diagram illustrating the operation of another conventional photoelectric switch.

[Explanation of symbols]

 31, 32 Photoelectric switch 33 Cases 33a, 33b Side wall 37 Circuit board 38 Receiving means 39 Exciting means 41 Core 42 Receiving coil 43 Auxiliary core 44 Core 45 Transmitting coil 46, 49 Auxiliary core 51, 52 Photoelectric switch 53 Case 53a, 53b Side wall 54 Receiving means 55 Exciting means 61 Core 62 Receiving coil 63 Auxiliary core 64 Core 65 Transmitting coil 66, 68 Auxiliary core L1 axis L2 axis

Claims (1)

[Scope of utility model registration request] 1. A light projecting element for intermittently projecting sensing light according to a timing signal of a predetermined cycle, a light receiving element for receiving reflected light reflected by an object to be detected, and these light projecting element and light receiving element. In the photoelectric detection device having a plurality of photoelectric switches that are arranged close to or in close contact with each other to determine the presence or absence of an object based on the presence or absence of reception of an optical pulse whose timing coincides with the sensing light. A photoelectric switch, which is disposed on one side of the photoelectric switch, receives a pulse-shaped magnetic signal, and a synchronization timing signal that synchronizes with the magnetic signal based on the magnetic signal or the magnetic signal Signal generating means for generating a delay timing signal delayed for a predetermined time and outputting the delayed timing signal to the light projecting element, and the synchronizing switch provided on the other side of the photoelectric switch. Exciting means for outputting a pulsed magnetic signal to the outside in synchronization with an imming signal or a delay timing signal is provided, and at least one of the receiving means and the exciting means is provided with an auxiliary core provided on the side wall, and these The receiving means, the exciting means and the auxiliary core are arranged on the same axis parallel to the arrangement direction of the photoelectric switch, and the exciting means of the photoelectric switch of the previous stage is connected to the receiving means of the photoelectric switch of the next stage through the auxiliary core. A photoelectric detection device characterized by transmitting a signal.