Optical Detection Unit

Abstract

To allow a light waveguide of a light detection unit to extend through a thin space or to be set in a thin space.SOLUTION: A light detection unit 400 includes: light waveguides 410 and 420 in the shape of a sheet wide in a horizontal direction, the light waveguides having cores and clads provided in layers in a vertical direction; and a connector unit 500 removably attached to a light projection connector or a light receiving connector of an optical sensor.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a light detection unit that is connected to an optical sensor having a light emitting element and a light receiving element. [Background technology]

[0002] Conventionally, there is known an optical detection unit that includes a light-emitting element that generates detection light to be irradiated onto a detection area, and a light-receiving element that receives the detection light from the detection area, and is configured to compare the light-receiving signal generated by the light-receiving element with a threshold value and output a signal indicating the presence or absence of an article as a comparison result (see, for example, Patent Document 1).

[0003] When performing light detection using this type of light detection unit, a light detection unit having an optical fiber on the light emitting side connected to a light emitting element and an optical fiber on the light receiving side connected to a light receiving element is generally used. The optical fiber constituting the light detection unit in Patent Document 1 is made up of a bundle optical fiber in which multiple optical fiber wires are bundled together. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4177178 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of a bundled optical fiber that bundles multiple optical fiber wires, such as the optical fiber of Patent Document 1, due to its structure, it was unavoidable that the outer diameter of the optical fiber would be several times or more the wire diameter of the optical fiber wires that make up the optical fiber.

[0006] However, there are cases where the optical fiber of the light detection unit needs to be passed through a narrow, thin space between components, or where it needs to be installed in such a thin space. In these cases, the bundled optical fiber of Patent Document 1 has a large outer diameter, making it difficult to accommodate.

[0007] The present invention has been made in view of the above points, and an object of the present invention is to enable the optical waveguide of a light detection unit to be passed through a thin space or to be installed in a thin space. [Means for solving the problem]

[0008] In order to achieve the above object, a first aspect of the present disclosure is based on an optical detection unit connected to an optical sensor having a light-emitting element that projects detection light toward a detection area, a light-receiving element that receives the detection light from the detection area, a light-emitting connection portion for optically coupling to the light-emitting element, a light-receiving connection portion for optically coupling to the light-receiving element, and a signal generation portion that compares a light-receiving signal generated by the light-receiving element with a threshold value and generates a detection signal indicating the comparison result.

[0009] The optical detection unit has an optical waveguide and a connector portion. The optical waveguide is a horizontally wide sheet-like member that guides light between a first end and a second end, has a core, and a clad surrounding the core, the core and the clad being arranged in layers in the vertical direction, the first end being connected to a light-emitting connection portion or a light-receiving connection portion so as to be optically coupled to the light-emitting element or the light-receiving element of the optical sensor, and the second end serving as a light-emitting end or a light-receiving end that emits light to a detection region or receives light from the detection region. The connector portion is a member to which the first end of the optical waveguide is connected, optically connects the first end of the optical waveguide directly or indirectly to the light-emitting connection portion or the light-receiving connection portion of the optical sensor, and is detachably attached to the light-emitting connection portion or the light-receiving connection portion.

[0010] According to this configuration, the optical waveguide has a sheet shape that is wide in the horizontal direction and has a core and a clad that are layered in the vertical direction, so that the optical waveguide can be made thin while ensuring the amount of light from the optical waveguide. The first end of the optical waveguide can be connected to the light-emitter connection portion or the light-receiver connection portion of the optical sensor by the connector portion. The connector portion is detachably attached to the light-emitter connection portion or the light-receiver connection portion, so that it is easy to connect the light detection unit to the optical sensor as needed, and to replace the light detection unit, etc.

[0011] In the second aspect of the present disclosure, the connector portion may have a convex portion that is inserted into the light-emitter connecting portion or the light-receiver connecting portion.

[0012] According to this configuration, the optical waveguide can be easily connected to the light-emitter connection portion or the light-receiving connection portion by inserting the convex portion of the connector portion into the light-emitter connection portion or the light-receiving connection portion. The convex portion may be provided on both the light-emitter side and the light-receiving side, and integrating the convex portion on the light-emitter side with the convex portion on the light-receiving side makes the connection even easier.

[0013] The optical sensor may be provided with a clamping mechanism for clamping the convex portion. The clamping mechanism may be in an unclamped state, the convex portion may be inserted into the light-emitting connection portion or the light-receiving connection portion, and after the insertion, the clamping mechanism may be in a clamped state, thereby preventing the convex portion from coming off the optical sensor.

[0014] In a third aspect of the present disclosure, the first end of the optical waveguide is exposed at the tip surface of the convex portion, and the convex portion can be configured to position the first end at the center position of the light emission surface of the light-emitting element or the light receiving surface of the light-receiving element when inserted into the light-emitting connection portion or the light-receiving connection portion.

[0015] With this configuration, the first end of the optical waveguide is exposed on the tip surface of the convex portion, so that by inserting the convex portion into the light-emitter connection portion or the light-receiver connection portion, the optical waveguide can be optically coupled to the light-emitting element or the light-receiving element. In this case, the first end of the optical waveguide is positioned at the center of the light-emitting surface of the light-emitting element or the light-receiving surface of the light-receiving element, so that a decrease in the amount of light at the connection portion can be suppressed.

[0016] In a fourth aspect of the present disclosure, the optical waveguide may include a light-projecting optical waveguide connected to the light-projecting connection portion of the optical sensor, the second end serving as a light-projecting end for projecting light toward a detection area, and a light-receiving optical waveguide connected to the light-receiving connection portion of the optical sensor, the second end serving as a light-receiving end for receiving light from the detection area. Further, the connector portion may be a member that integrally bundles together a light-projecting optical fiber that is connected to the first end of the light-projecting optical waveguide and optically coupled to the light-projecting connection portion in a removably manner, and a light-receiving optical fiber that is connected to the first end of the light-receiving optical waveguide and optically coupled to the light-receiving connection portion in a removably manner.

[0017] According to this configuration, the first end of the light-projecting optical waveguide can be connected to the light-projecting connection portion via the light-projecting optical fiber, and the first end of the light-receiving optical waveguide can be connected to the light-receiving connection portion via the light-receiving optical fiber. Since the light-projecting optical fiber and the light-receiving optical fiber are integrally bundled by the connector, the light-projecting optical fiber and the light-receiving optical fiber can be easily inserted and removed. Furthermore, since the light-projecting optical fiber and the light-receiving optical fiber function as relay members, it is possible to easily accommodate cases where the shapes of the optical path end faces of the light-projecting optical waveguide and the light-receiving optical waveguide differ from the shapes of the light-projecting connection portion and the light-receiving connection portion of the optical sensor. Furthermore, even if the spacing between the light-projecting optical fiber and the light-receiving optical fiber is determined by the requirements of the optical sensor, the spacing between the light-projecting optical waveguide and the light-receiving optical waveguide beyond the connector can be freely set, allowing it to be adapted to the object to be detected and the detection method.

[0018] In a fifth aspect of the present disclosure, the light projecting side optical fiber and the light receiving side optical fiber may be bundled optical fibers in which a plurality of optical fiber wires are bundled together.

[0019] In a sixth aspect of the present disclosure, a connection side of the light projecting side optical fiber with the light projecting optical waveguide may be such that a plurality of fiber lines constituting the light projecting side optical fiber are arranged side by side in a width direction of the light projecting optical waveguide.

[0020] That is, when the light projecting side optical fiber is configured using an optical fiber bundle, the end face shape is close to circular, whereas the light projecting optical waveguide is wide in the horizontal direction, which increases the difference in shape at the connection between the two, and as a result, there is a risk of increased optical loss. In this configuration, the multiple fiber lines that make up the light projecting side optical fiber are arranged side by side in the width direction of the light projecting optical waveguide, which reduces the difference in shape at the connection between the light projecting side optical fiber and the light projecting optical waveguide, and therefore optical loss can be reduced.

[0021] In addition, on the connection side of the light-receiving optical fiber with the light-receiving optical waveguide, a plurality of fiber lines constituting the light-receiving optical fiber may be arranged side by side in the width direction of the light-receiving optical waveguide.

[0022] According to the seventh aspect of the present disclosure, a rod lens that is long in a width direction of the light projection optical waveguide may be provided between the light projection side optical fiber and the light projection optical waveguide.

[0023] Between the light-receiving-side optical fiber and the light-receiving optical waveguide, a transparent elastic material that is long in the width direction of the light-receiving optical waveguide may be provided, or a transparent adhesive material may be provided.

[0024] An eighth aspect of the present disclosure can be based on an optical detection unit that is removably connected to an optical sensor having a light-emitting hole that is optically coupled to a light-emitting element in a housing, and a light-receiving hole that is optically coupled to a light-receiving element in the housing.

[0025] The optical detection unit includes a sheet-like first optical waveguide whose sensor side end is optically coupled to the light-projecting hole and whose detection end is positioned to project detection light toward the detection area, and which has a core through which light passes and a cladding surrounding the core; a sheet-like second optical waveguide whose sensor side end is optically coupled to the light-receiving hole and whose detection end is positioned to receive detection light from the detection area, and which has a core through which light passes and a cladding surrounding the core; a connector portion that integrates the first optical waveguide and the second optical waveguide; a light-projecting side convex portion provided in the connector portion, which has a substantially circular cross section that surrounds the sensor side end of the first optical waveguide and is substantially the same size as the light-projecting hole; and a light-receiving side convex portion provided in the connector portion, which has a substantially circular cross section that surrounds the sensor side end of the second optical waveguide and is substantially the same size as the light-receiving hole.

[0026] That is, because the first optical waveguide and the second optical waveguide are sheet-shaped, it is possible to ensure the light intensity of the optical waveguide while making the optical waveguide thin. When connecting the light detection unit to the optical sensor, the light-emitter convex portion integrated with the connector is simply inserted into the light-emitter hole of the optical sensor, which improves workability during connection. When the light-emitter convex portion is connected, it is positioned within the light-emitter hole because it is approximately the same size as the light-emitter hole. The light-receiving convex portion is also positioned in the same way. This reduces optical loss.

[0027] In the ninth aspect of the present disclosure, the outer diameter of the light-emitter side convex portion can be larger than the thickness dimension of the first optical waveguide.

[0028] The light-emitting side convex portion and the light-receiving side convex portion may be optical fibers.

[0029] The light projecting hole and the light receiving hole of the optical sensor may be aligned vertically relative to the housing, and the light projecting path and the light receiving path of the optical waveguide may be aligned horizontally relative to the sheet, and a twisted portion may be provided between the detection region of the optical waveguide and the connection hole. The twisted portion may be an optical fiber portion.

[0030] An indicator light for extracting light passing through the core of the optical waveguide to the outside may be provided on the light-emitting or light-receiving optical waveguide between the first end and the second end of the optical waveguide.

[0031] The light-projecting connection portion and the light-receiving connection portion may be circular holes, and the portion of the connector portion that can be detachably attached to the light-projecting connection portion or the light-receiving connection portion may be a portion in which the cores of the optical waveguide are arranged in a sheet-like shape.

[0032] The connector portion may be a portion for gripping the light-emitting and light-receiving optical waveguides. The connector may have a through hole for fixing.

[0033] The optical fiber and the optical waveguide may be optically coupled to each other within the connector. The optical waveguide may be provided with a fixing hole. [Effects of the Invention]

[0034] As described above, the optical waveguide, in which the core and clad are arranged in layers in the vertical direction, is formed in a sheet shape that is wide in the horizontal direction, so that the optical waveguide can be passed through or installed in a thin space while ensuring the light amount of the optical waveguide. Since the connector part is detachably attached to the light-emitter connecting part or the light-receive connecting part, it is easy to connect the light detection unit or replace the light detection unit. [Brief explanation of the drawings]

[0035] [Figure 1] FIG. 1 is a perspective view showing a state in which an optical sensor to which a light detection unit according to an embodiment of the present invention is connected is in use. [Figure 2] FIG. 2 is a block diagram of an optical sensor. [Figure 3] FIG. 3 is a vertical cross-sectional perspective view for explaining the element holder and the members held by the element holder. [Figure 4]FIG. 4 is a plan view showing a state in which the light guide portion and the connector portion of the light detection unit are separated. [Figure 5] FIG. 5 is a perspective view of the light-detecting unit, with the upper cover member of the light-guiding section omitted. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. [Figure 7] FIG. 7 is an enlarged plan view showing the vicinity of the end of the optical waveguide. [Figure 8A] FIG. 8A is an enlarged cross-sectional view of an optical waveguide having multiple cores. [Figure 8B] FIG. 8B is an enlarged cross-sectional view of an optical waveguide having one core. [Figure 9] FIG. 9 is an enlarged view of the tip side of the light guide part of the light detection unit shown in FIG. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. 4, showing a state in which a workpiece is detected. [Figure 11] FIG. 11 is a plan view showing an example in which the light detection unit is fixed to the mounting member by a fastening member. [Figure 12] FIG. 12 is a vertical cross-sectional view showing an example in which the light detection unit is fixed to the mounting member by a fastening member. [Figure 13] FIG. 13 is a plan view showing an example in which the light detection unit is fixed to the mounting member by a fixing plate. [Figure 14] FIG. 14 is a vertical cross-sectional view showing an example in which the light detection unit is fixed to the mounting member by a fixing plate. [Figure 15] FIG. 15 is a diagram showing an example in which the light detection unit is fixed to the mounting member by a hook-shaped member. [Figure 16] FIG. 16 is a plan view showing an example in which the light detection unit is directly fixed to the mounting member with screws. [Figure 17] FIG. 17 is a vertical cross-sectional view showing an example in which the light detection unit is directly fixed to the mounting member with a screw. [Figure 18] FIG. 18 is a perspective view showing an example in which a covering member is provided on the fixed portion of the light detection unit. [Figure 19]FIG. 19 is a perspective view showing an example in which a covering member is provided on a fixing portion of the light detection unit and both sides of the covering member in the width direction are fixed. [Figure 20] FIG. 20 is a perspective view showing an example in which a covering member is provided on a fixing portion of the light detection unit and the tip side of the covering member is fixed. [Figure 21] FIG. 21 is a perspective view showing an example in which a covering member is provided on a fixed portion of the light detection unit, and the portion between the tip side of the covering member and the light-projecting optical waveguide and the light-receiving optical waveguide is fixed. [Figure 22] FIG. 22 is a vertical cross-sectional view showing an example in which a light detection unit is fixed using a washer. [Figure 23A] FIG. 23A is a vertical cross-sectional view of a portion where optical waveguides are connected to each other. [Figure 23B] FIG. 23B is a plan view of a portion where the optical waveguides are connected to each other. [Figure 24] FIG. 24 is a perspective view showing a configuration example in which a light-projecting optical waveguide and a light-receiving optical waveguide are formed in a single member to achieve limited reflection. [Figure 25] FIG. 25 is a perspective view showing a configuration example in which reflectors made of separate members are provided at the tip portions of the light-projecting optical waveguide and the light-receiving optical waveguide to achieve limited reflection. [Figure 26] FIG. 26 is a plan view of a light detection unit showing an example of a pattern of an optical waveguide that takes into consideration the reduction of optical loss. [Figure 27A] FIG. 27A is a diagram showing an example in which a light output mirror surface is provided on the tip end surface of a light projection optical waveguide. [Figure 27B] FIG. 27B is a diagram showing an example in which the direction of the tip end face of the light projection optical waveguide is set by a direction setting member. [Figure 28] FIG. 28 is a plan view of a light detection unit showing an example of a pattern of an optical waveguide in which priority is given to the outer size. [Figure 29] FIG. 29 is a perspective view showing an example in which the light-projecting optical waveguide and the light-receiving optical waveguide are configured by arranging a plurality of optical fibers in the horizontal direction. [Figure 30] FIG. 30 is a plan view showing an example of limited reflection for emitting light from the tip of an optical waveguide. [Figure 31] FIG. 31 is a plan view showing another example of limited reflection for emitting light from the tip of an optical waveguide. [Figure 32] FIG. 32 is a plan view showing an example of limited reflection in which light is emitted from the side surface of the optical waveguide. [Figure 33] FIG. 33 is a plan view showing another example of limited reflection in which light is emitted from the side surface of the optical waveguide. [Figure 34] FIG. 34 is a plan view showing an example of use as a multipoint reflection type light detection unit. [Figure 35] FIG. 35 is a diagram showing an example in which the tip of an optical waveguide is bent. [Figure 36A] FIG. 36A is a diagram showing an example in which an optical waveguide and a mirror member are combined. [Figure 36B] FIG. 36B is a diagram showing another example in which an optical waveguide and a mirror member are combined. [Figure 37] FIG. 37 is a diagram showing an example of installing a retroreflector. [Figure 38A] FIG. 38A is a diagram showing an example of a transmission type photodetection unit in which the light-projecting optical waveguide and the light-receiving optical waveguide extend in the same direction. [Figure 38B] FIG. 38B is a diagram showing an example of a transmission type photodetection unit in which the light-projecting optical waveguide and the light-receiving optical waveguide extend in opposite directions. [Figure 39] FIG. 39 is a diagram showing an example of a transmission type photodetection unit in which the tip of the light-projecting optical waveguide and the tip of the light-receiving optical waveguide are opposed to each other. [Figure 40] FIG. 40 is a diagram showing an example of a transmission type optical detection unit when detecting a workpiece within the optical detection unit. [Figure 41] FIG. 41 is a diagram showing an example of a transmission type photodetection unit in which multiple optical paths are formed. [Figure 42] FIG. 42 is a plan view of the connector portion according to the first example. [Figure 43] FIG. 43 is a side view of the connector portion according to the first example. [Figure 44] FIG. 44 is a cross-sectional view taken along line AA in FIG. [Figure 45] FIG. 45 is a cross-sectional view taken along line BB in FIG. [Figure 46] FIG. 46 is a cross-sectional view taken along line CC in FIG. [Figure 47] FIG. 47 is a view of the connector portion according to the first example as viewed from the tip end side. [Figure 48] FIG. 48 is a perspective view of the connector portion according to the first example, as viewed from the side where the pressing member is disposed. [Figure 49] FIG. 49 is a perspective view of a connector portion according to the second example. [Figure 50] FIG. 50 is a plan view of a connector portion according to the third example. [Figure 51] FIG. 51 is a view of the connector portion according to the third example as viewed from the tip end side. [Figure 52] FIG. 52 shows an example in which a pre-installation adapter is provided. [Figure 53] FIG. 53 is a diagram showing an example in which the light-projecting hole and the light-receiving hole of the optical sensor are slit-shaped. [Figure 54] FIG. 54 is a perspective view showing a connector portion according to the fourth example. [Figure 55A] FIG. 55A is a perspective view showing the structure of a first example of a relay portion as viewed from the front side. [Figure 55B] FIG. 55B is a perspective view showing the structure of the first example of the relay portion as viewed from the back side. [Figure 55C] FIG. 55C is a perspective view showing the structure of a first example of the relay portion. [Figure 56A] FIG. 56A is a cross-sectional view showing a first example of a relay portion. [Figure 56B] FIG. 56B is a plan view showing a first example of the relay portion. [Figure 57] FIG. 57 is a plan view showing a second example of the relay portion. [Figure 58] FIG. 58 is a cross-sectional view showing a second example of the relay portion. [Figure 59] FIG. 59 is a plan view showing a third example of the relay portion. DETAILED DESCRIPTION OF THE INVENTION

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the following description of the preferred embodiments is merely exemplary in nature and is not intended to limit the present invention, its applications, or its uses.

[0037] Fig. 1 is a perspective view showing a state in which an optical sensor 1 connected to an optical detection unit 400 according to an embodiment of the present invention is in use. The optical detection unit 400 and the optical sensor 1 constitute an optical detection device 300. Fig. 1 is a perspective view of the optical detection device 300 seen obliquely from above, illustrating an example in which four optical detection devices 300 are installed next to each other on a DIN rail 2, with one of the optical detection devices 300 shown with its top cover 4 open.

[0038] Of the multiple optical detection devices 300 installed adjacent to the DIN rail 2, one is a parent device and the others are child devices. For example, when the parent device finishes projecting light, it sends a signal to the first child device to start projecting light, causing the first child device to start projecting light. When the first child device finishes projecting light, it sends a signal to the second child device to start projecting light, causing the second child device to start projecting light. Then, the third and fourth child devices start projecting light in sequence.

[0039] The example of use shown in FIG. 1 is just one example, and the optical detection device 300 can be used alone, or the optical detection device 300 can be fixed to a member other than the DIN rail 2 and used.

[0040] (Configuration of optical sensor 1) As shown in a block diagram of optical detection device 300 in FIG. 2, optical sensor 1 constituting optical detection device 300 includes light-projecting unit 102 and light-receiving unit 202. Light-projecting unit 102 outputs a predetermined pulse of light to optical detection unit 400. Light-emitting element 104 of light-projecting unit 102 is driven by an oscillation pulse supplied from light-projection power supply control circuit 302 to emit pulsed light. Meanwhile, light received by light-receiving unit 202 is photoelectrically converted by light-receiving element 204 and sent to control unit 308 via light-receiving element amplifier circuit 206, amplifier circuit 304, and A / D converter 306. As a result, detection is performed in synchronization with the pulsed light, and the detected signal is further converted into a DC signal or the like, and then output as an ON / OFF signal representing the detection result from I / O circuit 360 constituting the interface unit.

[0041] The optical sensor 1 includes a light-emitting circuit 106 for driving a light-emitting element 104. The light-emitting element 104 is a component for projecting detection light toward a detection area, and a typical example of the light-emitting element 104 is a light-emitting diode (LED), but is not limited to this.

[0042] The light-projecting circuit 106 includes a light-projecting APC circuit 108 and a monitor light-receiving element 110 such as a monitor PD. The light-projecting APC circuit 108 controls the output of the light-emitting element 104, i.e., the light emission amount, to a predetermined value. The monitor light-receiving element 110 of the light-projecting unit 102 is connected to a monitor signal amplifier circuit 114 and sends the received light amount to an LED light emission amount monitor circuit 312 via a monitor line. The LED light emission amount monitor circuit 312 converts the received light amount signal into a digital signal via an A / D converter 314 and supplies it to the control unit 308. The control unit 308 controls the light-projecting power supply control circuit 302 based on the light emission amount detected by the monitor light-receiving element 110 so that the light emission amount becomes a predetermined value, and performs feedback control by adjusting the amount of current in the light-projecting APC circuit 108 to drive the light-emitting element 104.

[0043] The optical sensor 1 includes a light-receiving circuit 208 for driving a light-receiving element 204. The light-receiving element 204 is a component that receives detection light from the detection region and is connected to a light-receiving element amplifier circuit 206. The amount of light received by the light-receiving element 204 is amplified by the light-receiving element amplifier circuit 206 and sent to an amplifier circuit 304, after which it is further amplified by the controller amplifier circuit 304. The analog signal amplified by the controller amplifier circuit 304 is converted into a digital signal via an A / D converter 306 and input to a signal generator 308a of the control unit 308. The signal generator 308a detects the amount of light received by the light-receiving element (photodiode PD) 204, compares the light-receiving signal generated by the light-receiving element 204 with a predetermined threshold value, and generates a detection signal indicating the comparison result. The detection signal generated by the signal generator 308a is finally output from an I / O circuit 360.

[0044] The control unit 308 is connected to a memory unit 326 for storing various setting values, a display circuit 328 for displaying information from the optical sensor 1, a switch input circuit 330 to which operation buttons 6 and 8 (shown in Figure 1) that are user interfaces for accepting setting value adjustments are connected, and an I / O circuit 360 for inputting and outputting data to and from the outside, and these circuits are driven by a controller power supply circuit 332.

[0045] The control unit 308 can be configured from an IC such as a central processing unit, FPGA, ASIC, etc. Each of the various circuits (reference numerals 108, 114, 206, 214, 302, 304, 306, 312, 314, 320, 328, 330, 332, and 360) may be configured from an IC, or the various circuits may be configured from a single IC, or the control unit 308 and the various circuits may be configured from a single IC.

[0046] As shown in Fig. 1, a display unit 334 is provided on the top surface of the housing 10 of the optical sensor 1. In this explanation, the side that is positioned on top when in the state of use shown in Fig. 1 is called "top", but this is defined merely for the sake of convenience, and the optical sensor 1 may be installed so that any side faces up.

[0047] The display unit 334 is configured with, for example, an organic EL display or a flat display, and is controlled by the display circuit 328 shown in Fig. 2. The display unit 334 may be a segment display as shown in Fig. 1. The display unit 334 is used to display the detected value (amount of received light), threshold value, etc. The display unit 334 may be configured with seven-segment displays arranged side by side.

[0048] As shown in Figure 1, operation buttons such as an up / down button 6, a mode button 8, and a set button 9 are arranged adjacent to the display unit 334 on the top surface of the housing 10 of the optical sensor 1. The optical sensor 1 has two channels for output, but is not limited to this. Reference numeral 16 denotes an operation indicator light for displaying the current output or detection status, reference numeral 16a denotes the operation indicator light for the first channel, and reference numeral 16b denotes the operation indicator light for the second channel.

[0049] By operating buttons 6, 8, 9, etc., it is possible to switch between a non-conversion display mode in which the detection value (amount of received light) and threshold value are displayed as is, and a conversion display mode in which the detection value (amount of received light for display) and threshold value for display converted using a display conversion rate or display conversion formula are displayed, and it is also possible to set the sensitivity, threshold value, etc. The display target, display mode, display switching operation, and display mode switching of the optical sensor 1 are described in detail in JP Patent Publication Nos. 2006-351380 and 2019-61885, and therefore the descriptions thereof are omitted by incorporating these specifications by reference.

[0050] An element holder 368 as shown in FIG. 3 is provided inside the housing 10 of the optical sensor 1. The element holder 368 is a member that holds the light-emitting element 104 and the light-receiving element 204. The element holder 368 houses a light-emitting member 370 and a light-receiving member 372. The light-emitting member 370 is a member that essentially constitutes the light-emitting unit 102 described above, and includes the light-emitting element 104, the monitor light-receiving element 110, and a reflector 380. The light-receiving member 372 is a member that essentially constitutes the light-receiving unit 202 described above, and includes the light-receiving element 204 and an LED 212 as an optical display light-emitting element. In this embodiment, the light-emitting element 104 and the light-receiving element 204 are aligned vertically. Specifically, the light-emitting element 104 is positioned above the light-receiving element 204. However, the light-receiving element 204 may be positioned above the light-emitting element 104, or the light-emitting element 104 and the light-receiving element 204 may be aligned horizontally.

[0051] The element holder 368 has a light-projecting hole 376 and a light-receiving hole 378 to which the light detection unit 400 is connected. The light-projecting hole 376 and the light-receiving hole 378 are configured as through-holes with circular cross sections, and are formed to penetrate the element holder 368. The light-projecting hole 376 constitutes a light-projecting connection portion for optically coupling to the light-emitting element 104 by directly or indirectly connecting to a light-projecting optical waveguide 410 (shown in FIG. 4 ) of the light detection unit 400. The light-receiving hole 378 constitutes a light-receiving connection portion for optically coupling to the light-receiving element 204 by directly or indirectly connecting to a light-receiving optical waveguide 420 of the light detection unit 400. The specific configurations of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 will be described later.

[0052] That is, the ends of light-projecting hole 376 and light-receiving hole 378 have first and second insertion openings 376a and 378a that open to the outer surface of element holder 368. Light-emitting element 104 is disposed on the back side of light-projecting hole 376. Light-emitting element 104 is mounted on light-projecting mounting board 382. Light-emitting element 104 is positioned so that the center of the light-emitting surface of light-emitting element 104 is located on an extension of the center line of light-projecting hole 376.

[0053] A light receiving element 204 is disposed at the back of the light receiving hole 378. The light receiving element 204 is mounted on a light receiving mounting substrate 384. The position of the light receiving element 204 is set so that the center of the light receiving surface of the light receiving element 204 is located on an extension of the center line of the light receiving hole 378. The space in which the light emitting element 104 is disposed and the space in which the light receiving element 204 is disposed are optically isolated. A glass plate 374, which is a light-transmitting member, is interposed between the light receiving element 204 and the end of the light receiving hole 378 on the back side.

[0054] (clamping mechanism) The optical sensor 1 has a clamping mechanism for clamping the light detection unit 400 in a connected state. The clamping mechanism is provided inside the housing 10, and is configured to be able to clamp the portions of the light detection unit 400 inserted into the light-projecting hole 376 and the light-receiving hole 378 (details will be described later) in the radial direction of the holes 376, 378. When the portions of the light detection unit 400 inserted into the light-projecting hole 376 and the light-receiving hole 378 are clamped by the clamping mechanism, the inserted portions are prevented from coming out of the light-projecting hole 376 and the light-receiving hole 378.

[0055] On the other hand, as shown in Fig. 1, an operating lever 7 for operating the clamping mechanism from the outside is provided on the outside of the housing 10. By moving the operating lever 7 in a predetermined direction, the clamping mechanism can be put into a clamped state. By moving the operating lever 7 in the opposite direction to the predetermined direction, the clamping mechanism can be put into an unclamped state.

[0056] The configuration of the clamp mechanism and operating lever 7 is not limited to the above-described configuration, and any configuration can be used as long as it is capable of clamping the portion inserted into the light-projecting hole 376 and the light-receiving hole 378 in the light detection unit 400.

[0057] (Overall configuration of the light detection unit 400) 4, the light detection unit 400 is a unit that includes a light guide section 401 and a connector section 500, and enables detection of a workpiece WK (shown in FIG. 10) by limited reflection. The connector section 500 will be described later.

[0058] Here, a sensor that detects workpiece WK by limited reflection is a type of sensor that limits the detection area of ​​the object, irradiates detection light, and receives the reflected light reflected by the workpiece WK in the detection area with a light receiving unit in order to detect whether the workpiece WK is present at a specified position.

[0059] Although details will be described later, the light detection unit 400 is provided with first to fourth insertion holes 402 to 405 through which fixing members such as screws are inserted.

[0060] 5 and 6, the light-guiding section 401 includes a light-emitting optical waveguide 410, a light-receiving optical waveguide 420, a light extraction member 430, an upper covering member 440, and a lower covering member 450. The tip side and base side of the light detection unit 400 are defined as shown in FIGS. 4 and 5. The base side of the light detection unit 400 is the side that is connected to the optical sensor 1 and is the side where the connector section 500 is provided. The tip side of the light detection unit 400 is the side that detects the workpiece WK (shown in FIG. 9, etc.).

[0061] As shown in FIG. 5, the light projection optical waveguide 410 is formed in a long, narrow strip shape so as to guide light between a base end (first end) and a tip end (second end) of the light detection unit 400. The base end is the sensor-side end, and the tip end is the detection end. As shown in FIG. 8A, the light projection optical waveguide 410 is in the form of a sheet that is wide in the horizontal direction, with the horizontal dimension (width dimension W) set longer than the vertical dimension (thickness dimension t). The main surfaces of the light projection optical waveguide 410 are the top and bottom surfaces. The side surfaces of the light projection optical waveguide 410 are surfaces located on both sides in the width direction. The light projection optical waveguide 410 can be used in a position where the horizontal direction faces the vertical direction as shown in FIG. 6, or in a position where the horizontal direction is tilted as shown in FIG. 6.

[0062] 8A, light projection optical waveguide 410 has multiple cores 411 arranged at intervals in the horizontal direction, and clad 412 surrounding cores 411. By changing the refractive index between cores 411 and clad 412, light incident on core 411 travels by undergoing total reflection at the boundary between core 411 and clad 412. There is almost no loss of light at this time.

[0063] The number of cores 411 can be set to any number and is not limited to the number shown in the figure. Providing multiple cores 411 is preferable because it allows for a larger amount of light to be emitted without increasing the thickness of the light projection optical waveguide 410. The cross-sectional shape of the cores 411 is not particularly limited, but can be, for example, rectangular. The clad 412 has an upper portion 412a that covers the cores 411 from above, a lower portion 412b that covers the cores 411 from below, and an intermediate portion 412c that is interposed between the cores 411 that are aligned horizontally. The upper portion 412a of the clad 412, the cores 411, and the lower portion 412b of the clad 412 are layered in the vertical direction and integrated.

[0064] 8A , the cores 411 located at both ends of the light projection optical waveguide 410 in the width direction are not covered with the cladding 412, but are exposed. However, the cores 411 located at both ends of the light projection optical waveguide 410 in the width direction may be covered with the cladding 412.

[0065] As shown in FIG. 7, which is an enlarged plan view of the vicinity of the tip of the light-projecting optical waveguide 410, the tip of the intermediate portion 412c of the cladding 412 does not have to reach the tip of the light-projecting optical waveguide 410.

[0066] 8B, the number of cores 411 may be one. When there is one core 411, it can be formed so as to have a cross section that is long in the width direction of the light projection optical waveguide 410. In this case, the middle portion 412c of the clad 412 is eliminated, and the clad 412 is composed of an upper portion 412a and a lower portion 412b. Both side surfaces of the core 411 in the width direction may be exposed or may be covered by the clad 412.

[0067] The light projection optical waveguide 410 is a so-called polymer optical waveguide. Examples of materials for the light projection optical waveguide 410 include, but are not limited to, resins such as acrylic, epoxy, siloxane, silicone, polyimide, polysilane, polynorbornene, and fluororesin. Any material that satisfies the desired optical and physical properties can be used. Only one of the above materials may be used, or a mixture of multiple materials may be used. Additives may also be added to the above materials to improve the optical and physical properties. Forming the light projection optical waveguide 410 from the above resins provides the light projection optical waveguide 410 with flexibility and flexibility, as well as a predetermined heat resistance.

[0068] The method for forming core 411 of light projecting optical waveguide 410 can be selected depending on the material, for example, physical etching (RIE method), stamping (mold method), photobleaching (UV conversion method), direct light exposure (UV curing method), etc., but is not limited to these.

[0069] 6, the light-receiving optical waveguide 420 can be configured similarly to the light-projecting optical waveguide 410, and has a core 421 and a cladding 422. The light-receiving optical waveguide 420 and the light-projecting optical waveguide 410 may be identical to each other, or may have different dimensions. The light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are disposed with a gap therebetween in the width direction. The gap between the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 is not particularly limited, but can be set to, for example, 5 mm or more in consideration of screw fastening, which will be described later.

[0070] The light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are covered by an upper covering member 413 and a lower covering member 414, which serve as reinforcing members, on the outside of the light-projecting optical waveguide 410, and by an upper covering member 423 and a lower covering member 424, which serve as reinforcing members, on the outside of the light-receiving optical waveguide 420, and are further covered by an upper covering member 440 and a lower covering member 450, which are optically opaque. The upper covering member 413 and the lower covering member 414, and the upper covering member 423 and the lower covering member 424, are first covering members. The upper covering member 440 and the lower covering member 450 are second covering members. Therefore, the light-detecting unit 400 is provided with covering members having a stacked structure.

[0071] That is, the lower surface of the cladding 412 of the light-leading optical waveguide 410 is covered by a lower covering member 414, the lower surface of the cladding 421 of the light-receiving optical waveguide 420 is covered by a lower covering member 424, and these lower covering members 414 and 424 are covered by a lower covering member 450. Furthermore, the upper surface of the cladding 412 of the light-leading optical waveguide 410 is covered by an upper covering member 413, and the upper surface of the cladding 421 of the light-receiving optical waveguide 420 is covered by an upper covering member 423, and these upper covering members 413 and 423 are covered by an upper covering member 440. As shown in FIGS. 4 and 5 , the upper covering member 440 and the lower covering member 450 are formed in the shape of sheets extending from the distal ends of the light-leading optical waveguide 410 and the light-receiving optical waveguide 420 toward the proximal ends. The base end sides of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 protrude from the base end sides of the upper covering member 440 and the lower covering member 450, and are not covered by the upper covering member 440 and the lower covering member 450. The portions of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 that are not covered by the covering members 440, 450 are the portions that are inserted into and removed from the optical sensor 1.

[0072] Hereinafter, the upper covering member 413, the lower covering member 414, the upper covering member 423, and the lower covering member 424 will not be described because they are provided on the top and bottom surfaces of the optical waveguide 410 or the optical waveguide 420. That is, the upper covering member 413 and the lower covering member 414 can be components that constitute a part of the optical waveguide 410, in which case the upper covering member 413 and the lower covering member 414 can be referred to as the optical waveguide 410. For example, when describing "drilling a hole in the optical waveguide 410," this also means drilling holes in the upper and lower covering members 413 and 414 on the top and bottom surfaces of the optical waveguide 410, but a description of this will be omitted to avoid complication. Similarly, the upper covering member 423 and the lower covering member 424 can be components that constitute a part of the optical waveguide 420, in which case the upper covering member 423 and the lower covering member 424 can be referred to as the optical waveguide 420. It goes without saying that the upper covering member 413, the lower covering member 414, the upper covering member 423, and the lower covering member 424 may be provided, or only some of them may be provided, or none of them may be provided. Furthermore, the upper covering member 413 and the lower covering member 414 may be treated as members separate from the optical waveguide 410, and the upper covering member 423 and the lower covering member 424 may be treated as members separate from the optical waveguide 420.

[0073] The upper covering member 440 and the lower covering member 450 have a light-blocking property that blocks light emitted from the light-emitting element 104. The upper covering member 440 and the lower covering member 450 do not need to block 100% of the light emitted from the light-emitting element 104, and may have a light-blocking property of, for example, 90% or more. The upper covering member 440 and the lower covering member 450 may have a light-blocking property according to the wavelength of light emitted from the light-emitting element 104 and an attenuation effect that attenuates the light. The color of the upper covering member 440 and the lower covering member 450 may be a color other than black, such as navy blue, from an external perspective. The resin material that constitutes the upper covering member 440 and the lower covering member 450 can be colored by printing.

[0074] The light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are made of a material that is transparent to the light propagating therethrough. The upper covering member 413, the lower covering member 414, the upper covering member 423, and the lower covering member 424 are made of an opaque material that reinforces the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 and reflects light at their interfaces. One example of such a material is polyimide. The upper covering member 440 and the lower covering member 450 that are provided on the outside thereof have light-blocking properties as described above, and are colored or otherwise processed to have higher light-blocking properties than the upper covering member 413, the lower covering member 414, the upper covering member 423, and the lower covering member 424. Upper covering member 440 and lower covering member 450, as well as upper covering member 413, lower covering member 414, upper covering member 423, and lower covering member 424 may be made of the same material, polyimide, and differences in light-blocking properties may be provided by printing black on upper covering member 440 and lower covering member 450. Note that air is present in two horizontal locations between light-receiving optical waveguide 420 and upper covering member 440 and lower covering member 450, and two horizontal locations between light-projecting optical waveguide 410 and upper covering member 440 and lower covering member 450 in FIG. 6 . Air may be present when covering the laminated body made up of light-projecting optical waveguide 410, upper covering member 413, and lower covering member 414 and the laminated body made up of light-receiving optical waveguide 420, upper covering member 423, and lower covering member 424 with upper covering member 440 and lower covering member 450. This allows light leakage to be reduced by the difference in refractive index between light-projecting optical waveguide 410 and light-receiving optical waveguide 420 and air.

[0075] An adhesive layer or bonding layer is provided on the back surface of the upper covering member 440. The upper covering member 440 is adhesively or bonded to the upper surface of the clad 412 of the light-leading optical waveguide 410 and the upper surface of the clad 421 of the light-receiving optical waveguide 420. In this way, the upper covering member 440 is configured integrally with the light-leading optical waveguide 410 and the light-receiving optical waveguide 420.

[0076] An adhesive layer or bonding layer is also provided on the back surface of the lower covering member 450. The lower covering member 450 is adhesively or bonded to the lower surface of the clad 412 of the light-leading optical waveguide 410 and the lower surface of the clad 421 of the light-receiving optical waveguide 420. In this way, the lower covering member 450 is configured integrally with the light-leading optical waveguide 410 and the light-receiving optical waveguide 420.

[0077] The upper covering member 440 and the lower covering member 450 are adhered or bonded to each other on both sides in the width direction. This makes it possible to suppress light leakage from both sides in the width direction. Furthermore, the upper covering member 440 and the lower covering member 450 are also adhered or bonded to each other between the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. This makes it possible to optically isolate the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420.

[0078] The upper covering member 440 and the lower covering member 450 can be made of, for example, a flexible resin tape, resin sheet, or resin film. Usable resin materials include, but are not limited to, polyimide, and any resin material may be used as long as it is flexible and has enough strength to prevent breakage during fixation, as described below. When the upper covering member 440 and the lower covering member 450 are colored, they may be colored with a pigment or dye.

[0079] Alternatively, the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 may be covered with a single covering member without being separated into the upper covering member 440 and the lower covering member 450. The covering members may be bag-shaped, and their shapes are not particularly limited. The upper covering member 440 and the lower covering member 450 are formed so as not to cover the light-projecting end, which is the tip of the light-projecting optical waveguide 410, or the light-receiving end, which is the tip of the light-receiving optical waveguide 420, thereby enabling optical coupling between the light extraction member 430 and the light-projecting end of the light-projecting optical waveguide 410 and the light-receiving end of the light-receiving optical waveguide 420.

[0080] The upper covering member 440 and the lower covering member 450 may also be marked with letters, symbols, marks, etc. indicating, for example, the manufacturer's name, product number, model number, etc. of the light detection unit 400. By making the upper covering member 440 and the lower covering member 450 a dark color such as black and the letters, symbols, marks, etc. a light color such as white, the letters, symbols, marks, etc. become more noticeable. By marking the letters, symbols, marks, etc. only on the top surface, for example, the user can easily tell which is the top surface. The upper covering member 440 or the lower covering member 450 may also be marked with, for example, letters, symbols, marks, etc. as a direction indicator indicating the up / down, front / back, etc.

[0081] By providing the upper covering member 440 and the lower covering member 450, leakage of light from the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 can be suppressed when the light detection unit 400 is bent and installed. Furthermore, by integrating the upper covering member 440 and the lower covering member 450 with the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420, the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 can be reinforced and their strength increased. For example, when the light detection unit 400 is bent and installed, the upper covering member 440 and the lower covering member 450 can suppress bending of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. On the other hand, because the upper covering member 440, the lower covering member 450, the light-projecting optical waveguide 410, and the light-receiving optical waveguide 420 are flexible, the light detection unit 400 can be bent, twisted, or deflected, for example, when going around an obstacle, improving the degree of freedom in handling. Even in this way, leakage of light from the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 can be suppressed, and therefore detection performance is not adversely affected.

[0082] Furthermore, in this embodiment, the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are characterized by being thin and sheet-like, which makes it possible to arrange the light detection unit 400 in a narrow space. On the other hand, if the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are thin, they may be easily bent and tangled during handling, which may result in poor handleability, but by providing the upper covering member 440 and the lower covering member 450, bending of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 is appropriately suppressed and they are less likely to tangle, resulting in good handleability.

[0083] The rigidity of the resin material constituting the upper covering member 440 and the lower covering member 450 can be set to be higher than the rigidity of the resin material constituting the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. This further enhances the reinforcing effect of the upper covering member 440 and the lower covering member 450. Furthermore, the resin material constituting the upper covering member 440 and the lower covering member 450 can be made less slippery than the resin material constituting the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. This makes it less likely that the light-detecting unit 400 will slip when installed.

[0084] 8A and 6, core 411 is partially exposed at the horizontal end face of light projection optical waveguide 410. This is to strengthen the end face. For example, if the clad constituting light projection optical waveguide 410 is manufactured by modifying the core, core 411 will be stronger than clad 412. Therefore, by exposing core 411, the strength of the end face side can be increased.

[0085] 7, the end face of light projection optical waveguide 410 on the tip side is core 411. The end faces in the horizontal direction (the left and right ends on the paper surface of FIG. 7) are also core 411. This is because core 411 is stronger than clad 412, and the portion exposed to the outside is core 411 rather than clad 412.

[0086] 9, the light extraction member 430 is disposed at the tip of the light detection unit 400, and is formed in a plate shape that extends from the tip of the light-projecting optical waveguide 410 to the tip of the light-receiving optical waveguide 420. The thickness of the light extraction member 430 is set to be approximately the same as the thickness of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. Note that, although the left and right sides of the light detection unit 400 are defined as shown in FIG. 9, this is merely for the convenience of explanation and does not limit the actual usage state.

[0087] The light extracting member 430 can be made of a material having the same light-guiding properties as the material of the core 411 of the light projecting optical waveguide 410. As shown in FIG. 10 , the light extracting member 430 is made of a single core 430a. The light extracting member 430 may have a cladding similar to the cladding 412 of the light projecting optical waveguide 410. The lower surface of the light extracting member 430 is adhesively or bonded to the lower covering member 450, and the upper surface of the light extracting member 430 is adhesively or bonded to the upper covering member 440. This prevents the relative positions of the light extracting member 430, the light projecting optical waveguide 410, and the light receiving optical waveguide 420 from shifting, and allows the light extracting member 430 to be covered by the upper covering member 440 and the lower covering member 450.

[0088] 9, the right side of the light extraction member 430 abuts against the tip end of the light projection optical waveguide 410. This optically couples the light extraction member 430 and the multiple cores 411 of the light projection optical waveguide 410, so that light that has traveled through the cores 411 of the light projection optical waveguide 410 is incident on the right side portion of the light extraction member 430. A transparent elastic material or a transparent adhesive material may be interposed between the light extraction member 430 and the tip end of the light projection optical waveguide 410.

[0089] A right inclined surface 431 is formed at the right end of the light extracting member 430. The right inclined surface 431 is a reflective surface, and the traveling direction of light incident on the right side of the light extracting member 430 is changed to the left by the right inclined surface 431. The inclination angle of the right inclined surface 431 with respect to the longitudinal direction of the light projection optical waveguide 410 is set so that the direction of light incident on the right side of the light extracting member 430 is changed to the left.

[0090] A light-emitting mirror surface 432 serving as a light-emitting portion is provided on the right side of the upper surface of the light-extracting member 430. The light-emitting mirror surface 432 is configured as a surface inclined at a predetermined angle with respect to the upper surface of the light-extracting member 430. The direction of light that enters the right side of the light-extracting member 430 and is converted to the left by the right-side inclined surface 431 is emitted by the light-extracting mirror surface 432 from the main surface side (upper surface side) of the light-projecting optical waveguide 410 toward the detection region R (shown in FIG. 10 ). The tip end of the light-projecting optical waveguide 410 serves as a light-projecting end, which projects light into the detection region R via the light-extracting member 430. The light-extracting mirror surface 432 can be obtained, for example, by laser processing. A vapor-deposited film of metal may be formed on the light-extracting mirror surface 432 to improve reflectance.

[0091] The light incidence and emission aperture angle NA can be set to approximately 0.2, which allows for a small light projection spot and light reception field of view without the need for additional lenses. The optical paths shown in the figures may be reversed. That is, the light projection side in each figure may be the light reception side, and the light reception side may be the light projection side. The distance between the light detection unit 400 and the workpiece WK is not particularly limited, but can be, for example, approximately 0 mm to 3 mm.

[0092] The detection area R is an area where the workpiece WK to be detected is placed, and is an area where the workpiece WK is to be placed. In this embodiment, it is located above the light extracting member 430. The light emission angle can be changed by changing the angle of the light emitting mirror surface 432.

[0093] The left side of the light extraction member 430 abuts against the tip of the light-receiving optical waveguide 420. This optically couples the light extraction member 430 and the light-receiving optical waveguide 420, so that light that has traveled through the left portion of the light extraction member 430 enters the core 421 of the light-receiving optical waveguide 420. A transparent elastic material or a transparent adhesive material may be interposed between the light extraction member 430 and the tip of the light-receiving optical waveguide 420.

[0094] 10, when a workpiece WK is placed in the detection area R, the light irradiated onto the workpiece WK is reflected and travels downward, and a light incident mirror surface 433 serving as a light incident portion is provided on the upper surface of the light extraction member 430 to correspond to the area that this light reaches. The light incident mirror surface 433 is configured as a surface inclined at a predetermined angle with respect to the upper surface of the light extraction member 430, and the inclination angle of the light incident mirror surface 433 is set so that the incident light travels to the left.

[0095] As shown in FIG. 9 , a left inclined surface 434 is formed at the left tip of the light extracting member 430. The left inclined surface 434 is a reflective surface, and the traveling direction of light that enters the light extracting member 430 from the light incident mirror surface 433 and travels leftward is changed by the left inclined surface 434 and then enters the light-receiving optical waveguide 420. The inclination angle of the left inclined surface 434 with respect to the longitudinal direction of the light-receiving optical waveguide 420 is set so that the light that enters the left side of the light extracting member 430 is changed in direction toward the base end of the light detection unit 400. The tip of the light-receiving optical waveguide 420 is a light-receiving end that receives light from the detection region R via the light extracting member 430. The light-emitting mirror surface 432 and the light-incident mirror surface 433 are not covered by the upper cover member 440 and are exposed.

[0096] The light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 have multiple cores 411, 421 arranged therein, but the light-extracting member 430 has a single core. When multiple cores are included, it is difficult to align the cores with each other during optical coupling, but it is easy to optically couple multiple cores to a core with a larger cross-sectional area. Therefore, by butting the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 with the light-extracting member 430, optical coupling can be achieved while suppressing optical loss, and assembly is easy.

[0097] (Fixing structure of the optical detection unit 400) As shown in FIGS. 11 and 12 , when the light detection unit 400 is installed, it can be fixed to, for example, a mounting member 600, which is the mounting target. The mounting member 600 may be, for example, a component constituting a part of various devices, or may be a surface plate or the like. In the example shown in FIGS. 11 and 12 , the light detection unit 400 is fixed to the surface of the mounting member 600 with a fixing member 601 made of an adhesive, a glue, double-sided tape, or the like. In this case, the lower surface of the lower cover member 450 serves as the installation surface and is the surface fixed to the mounting member 600. When the installation surface is horizontal, the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are aligned horizontally. However, as shown in FIG. 3 , the light-projecting hole 376 and the light-receiving hole 378 of the optical sensor 1 are aligned vertically, so the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 need to be twisted along the way. In this case, too, the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420 covered by the upper covering member 440 and the lower covering member 450 are sheet-shaped and have a predetermined degree of softness and flexibility, so they can be easily handled.

[0098] A wide portion 400a that is wider than the base end side is provided on the tip end side of the light detection unit 400. By fixing this wide portion 400a to the mounting member 600 with a fixing member 601, the area of ​​the fixed portion can be increased.

[0099] 13 and 14 show an example in which the light detection unit 400 is fixed to a mounting member 600 with screws using a fixing plate 602. The fixing plate 602 is made of, for example, hard resin or metal and is formed to extend along the upper surface of the mounting member 600. The fixing plate 602 is formed to be wider than the width of the tip end of the light detection unit 400. Insertion holes (not shown) through which screws 603 are inserted are formed on both sides of the width of the fixing plate 602. These insertion holes are positioned outside the tip end of the light detection unit 400. When the fixing plate 602 is placed on the upper surface of the tip end of the light detection unit 400 and the screws 603 are inserted into the insertion holes and screwed into the mounting member 600, the tip end of the light detection unit 400 can be sandwiched and fixed between the fixing plate 602 and the mounting member 600 in the thickness direction. The fixing plate 602 is positioned so as not to cover the light exit mirror surface 432 and the light entrance mirror surface 433. Instead of the screws 603, nails, staplers, etc. may also be used.

[0100] FIG. 15 shows an example in which the light detection unit 400 is fixed to the mounting member 600 using a hook-shaped member 604. FIG. 15 is a longitudinal cross section perpendicular to the longitudinal direction of the light detection unit 400. The hook-shaped member 604 is formed to surround the mounting member 600 and is made of, for example, hard resin or metal. The hook-shaped member 604 has a pair of legs 604a. By engaging the hook-shaped member 604 with the mounting member 600 from above the tip side of the light detection unit 400, the tip side of the light detection unit 400 can be sandwiched and fixed between the hook-shaped member 604 and the mounting member 600 in the thickness direction. The hook-shaped member 604 is positioned so as not to cover the light-emitting mirror surface 432 and the light-incident mirror surface 433.

[0101] 16 and 17 show an example in which the light detection unit 400 is fixed by directly screwing it to the mounting member 600. The light detection unit 400 is provided with first to fourth insertion holes 402 to 405 (shown in FIG. 4) through which screws 605 serving as fixing members used when installing the light detection unit 400 on the mounting member 600 are inserted. The first to fourth insertion holes 402 to 405 vertically penetrate the upper covering member 440 and the lower covering member 450. That is, the upper covering member 440 and the lower covering member 450 have portions that cover the claddings 412 and 422 between the light-emitting ends and light-receiving ends of the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420, respectively, and these portions that cover the claddings 412 and 422 between the light-emitting ends and light-receiving ends are the portions that are fixed to the mounting member 600.

[0102] The first insertion hole 402 is located closest to the base end, and the fourth insertion hole 405 is located closest to the tip end. The second insertion hole 403 and the third insertion hole 404 are located between the first insertion hole 402 and the fourth insertion hole 405, with the second insertion hole 403 being closer to the base end than the third insertion hole 404. The third insertion hole 404 is close to the fourth insertion hole 405. The first to fourth insertion holes 402 to 405 may also be configured as elongated holes. The first to fourth insertion holes 402 to 405 are located in portions of the covering members 440, 450 that correspond to the positions between the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420, and are designed not to affect the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420.

[0103] 16 and 17, when a screw 605 is inserted into the first to fourth insertion holes 402 to 405 and screwed into the mounting member 600, the peripheral edges of the first to fourth insertion holes 402 to 405 can be sandwiched between the head of the screw 605 and the mounting member 600 to fix them. The number of insertion holes and the number of screws 605 are not limited to four and may be, for example, one. The peripheral edges of the first to fourth insertion holes 402 to 405 become fixed portions that are fixed to the mounting member 600. A washer (not shown) may be interposed between the head of the screw 605 and the peripheral edges of the first to fourth insertion holes 402 to 405.

[0104] 18, covering member 450 may be provided at a portion that is fixed to mounting member 600. In this case, a screw 605 may be disposed so as to penetrate covering member 450 and be screwed into mounting member 600. This allows covering member 450 to be sandwiched and fixed between the head of screw 605 and mounting member 600.

[0105] 19 , when covering member 450 is provided at a portion where it is fixed to mounting member 600, mounting regions 602 in which light-leading optical waveguide 410 and light-receiving optical waveguide 420 and / or covering member 450 are spread out may be provided on both widthwise sides of covering member 450, and holes formed in mounting regions 602 may be fastened with screws 605. In this case, covering member 450 can be fixed by being sandwiched between the heads of screws 605 and mounting member 600 on both widthwise sides.

[0106] 20 , when covering member 450 is provided at a portion where it is fixed to mounting member 600, a mounting region 602 in which light-leading optical waveguide 410 and light-receiving optical waveguide 420 and / or covering member 450 are spread out may be provided on the tip side of covering member 450, and holes formed in mounting region 602 may be fastened with screws 605. In this case, covering member 450 can be fixed by being sandwiched between the heads of screws 605 and mounting member 600.

[0107] 21 , when the covering member 450 is provided at a portion to be fixed to the mounting member 600, a mounting region 602 in which the light leading optical waveguide 410 and the light receiving optical waveguide 420 and / or the covering member 450 are expanded may be provided in a portion between the tip side of the covering member 450 and the light leading optical waveguide 410 and the light receiving optical waveguide 420, and the covering member 450 may be fixed using holes formed in the mounting region 602. The tip side of the covering member 450 can be fixed by sandwiching it between the head of a screw 605 and the mounting member 600, and the portion of the covering member 450 between the light leading optical waveguide 410 and the light receiving optical waveguide 420 can be fixed by passing a screw 605 through the mounting member 600 and screwing it into the mounting member 600.

[0108] As shown in FIG. 22, the light detection unit 400 can also be fixed using a screw 606 and a washer 607. FIG. 22 is a vertical cross section of the light detection unit 400 perpendicular to the longitudinal direction, showing the portion where the fourth insertion hole 405 is formed. The washer 607 is disposed below the light detection unit 400. The washer 607 has an annular portion 607a formed thereon to be inserted into the fourth insertion hole 405. The screw 606 is inserted into the annular portion 607a of the washer 607 and threadedly engaged with the mounting member 600. At this time, the head of the screw 606 can be received by the upper end of the annular portion 607a of the washer 607, making it difficult for a strong force to act in the vertical direction on the light detection unit 400. This makes it possible to prevent damage to the light-emitting optical waveguide 410, the light-receiving optical waveguide 420, and the light extraction member 430. The fixing portion is not limited to the fourth insertion hole 405, but may be any of the first to third insertion holes 402 to 404, and the same fixing method may be adopted for any two or more of these through holes 402 to 405.

[0109] The above-described fixing method is one example, and various methods can be used as long as they can fix the light detection unit 400 to the mounting member 600. For example, fixing methods using cable ties, wires, etc. can also be used. Furthermore, the light detection unit 400 can be fixed to the mounting member 600 by combining any two or more of the above-described fixing methods.

[0110] Furthermore, the connector portion 500 may be omitted, and the base ends of the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420 may be fixed to the optical sensor 1 so that they cannot be removed.

[0111] (Optical waveguide connection structure) 23A is a vertical cross-sectional view of the connection portion of two light projection optical waveguides 410A and 410B, and as shown in this figure, the two light projection optical waveguides 410A and 410B can be connected for use. The end face of light projection optical waveguide 410A and the end face of light projection optical waveguide 410B may be directly butted together for connection, or a transparent elastic material 460 or a transparent adhesive may be interposed between the end faces of light projection optical waveguides 410A and 410B to prevent an air gap from remaining between them.

[0112] A continuous reinforcing member 461 may be provided from the light projection optical waveguide 410A to the light projection optical waveguide 410B. The reinforcing member 461 is a flexible tape-like member that is attached to the lower surface of the light projection optical waveguide 410A and the lower surface of the light projection optical waveguide 410B. The reinforcing member 461 preferably has a property of not stretching or shrinking in the longitudinal direction of the light projection optical waveguide 410A. This prevents a gap from being formed between the light projection optical waveguides 410A and 410B when the two light projection optical waveguides 410A and 410B are pulled in directions away from each other, for example, and suppresses a decrease in efficiency. The reinforcing member 461 may also be provided on the upper surfaces of the light projection optical waveguide 410A and the light projection optical waveguide 410B.

[0113] 23B is a plan view of the connection portion of two light projection optical waveguides 410A, 410B, and as shown in this figure, the two light projection optical waveguides 410A, 410B can be connected and used. As shown in the connection portion located in the center in the left-right direction in FIG. 23B, the cladding 412 does not have to extend to the vicinity of the interface. By butting the cores 411 together, optical coupling sufficient to allow light to propagate can be obtained. Note that the cores 411 may also be butted together.

[0114] (Example of optical waveguide formation) 24 shows a configuration example in which limited reflection is achieved by forming a light-projecting optical waveguide 410 and a light-receiving optical waveguide 420 in a single optical waveguide forming member 470. The light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are provided on both sides in the width direction of the optical waveguide forming member 470. Although not shown in this figure, the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are each composed of a core and a cladding, as shown in FIG. 8A etc.

[0115] The tip side of the light-projecting optical waveguide 410 is bent in a direction approaching the light-receiving optical waveguide 420 at the tip side of the optical waveguide forming member 470. A light-emitting mirror surface 432 is formed on the optical waveguide forming member 470 so as to correspond to the tip portion of the light-projecting optical waveguide 410. As a result, the tip portion of the light-projecting optical waveguide 410 becomes a light-projecting end, and projects light into the detection region R via the light-emitting mirror surface 432.

[0116] Furthermore, the tip side of the light-receiving optical waveguide 420 is bent toward the light-projecting optical waveguide 410 at the tip side of the optical waveguide forming member 470. A light-incident mirror surface 433 is formed on the optical waveguide forming member 470 so as to correspond to the tip of the light-receiving optical waveguide 420. As a result, the tip of the light-receiving optical waveguide 420 becomes a light-receiving end, and receives light from the detection region R via the light-incident mirror surface 433. In this example, the light-extracting member 430 is not provided separately, and the light-extracting mirror surface 432 and the light-incident mirror surface 433 can be provided on the optical waveguide forming member 470, in which the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are provided. This prevents relative positional misalignment between the components, thereby suppressing a decrease in detection accuracy. This configuration can also be described as an integrated structure in which the light-extracting member is incorporated into the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420.

[0117] 25 shows a configuration example in which limited reflection is achieved by providing reflectors 471 made of separate members at the tip portions of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. The reflector 471 is made of a resin material with high light reflectivity, such as white, and the tip portions of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are inserted into and held in place. The tip portion of the light-projecting optical waveguide 410 is cut in a direction inclined with respect to the longitudinal direction of the light-projecting optical waveguide 410 and abuts against a first inner surface 471a of the reflector 471. Light that has traveled through the light-projecting optical waveguide 410 is reflected by the first inner surface 471a of the reflector 471 and its traveling direction is changed toward the light-receiving optical waveguide 420. The reflector 471 is provided with a light emitting mirror surface 432, and when light that has traveled through the light projection optical waveguide 410 is reflected by the first inner surface 471a of the reflector 471, it reaches the light emitting mirror surface 432 and proceeds to the detection region R via this light emitting mirror surface 432.

[0118] Further, the tip end of the light-receiving optical waveguide 420 is also cut in a direction inclined with respect to the longitudinal direction of the light-receiving optical waveguide 420, and abuts against the second inner surface 471b of the reflector 471. The reflector 471 is provided with a light-incident mirror surface 433 adjacent to the light-emitting mirror surface 432. Light from the detection region R is incident on the second inner surface 471b of the reflector 471 via the light-incident mirror surface 433, reflected by the second inner surface 471b, and then incident on the light-receiving optical waveguide 420. In this example, the tip ends of the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420 can be held by the reflector 471, and therefore, relative positional deviation between the components can be suppressed.

[0119] 26 is a plan view of the light detection unit 400 showing an example of an optical waveguide pattern that takes into consideration the reduction of optical loss. The light projection optical waveguide 410 extends in a curved manner while maintaining a large curvature near its tip end, and the light reception optical waveguide 420 also extends in a curved manner while maintaining a large curvature near its tip end. Increasing the curvatures of the light projection optical waveguide 410 and the light reception optical waveguide 420 increases the width of the light detection unit 400. However, if the layout of the light detection unit 400 allows for an increase in the width of the light detection unit 400, using a pattern with a large curvature as in this example can reduce optical loss.

[0120] 27A, a light-emitting mirror surface 432 can be provided at the tip of the light-projecting optical waveguide 410. Similarly, a light-incident mirror surface 433 can be provided at the tip of the light-receiving optical waveguide 420 (see FIG. 26).

[0121] 27B, the light emission direction can be set to a direction that allows limited reflection by setting the direction of tip end surface 410a of light projection optical waveguide 410 with direction setting member 472. The light incident side can also be set in the same way with a direction setting member (not shown).

[0122] FIG. 28 is a plan view of the light detection unit 400, showing an example of a pattern of optical waveguides that prioritizes external size. The vicinity of the tip of the light-emitting optical waveguide 410 extends away from the light-receiving optical waveguide 420, and the vicinity of the tip of the light-receiving optical waveguide 420 also extends away from the light-emitting optical waveguide 410. However, compared to the example shown in FIG. 26 , the distance between the vicinity of the tip of the light-emitting optical waveguide 410 and the vicinity of the tip of the light-receiving optical waveguide 420 is set shorter. This allows the width of the light detection unit 400 to be narrowed, making it suitable for installation locations with limited width. A light-emitting mirror surface 432 can be provided at the tip of the light-emitting optical waveguide 410, and a light-incident mirror surface 433 can be provided at the tip of the light-receiving optical waveguide 420. The configurations shown in FIGS. 27A and 27B can also be applied to the example shown in FIG. 28 .

[0123] 29 shows an example in which the light projecting optical waveguide 410 and the light receiving optical waveguide 420 are each configured by arranging a plurality of optical fibers in the horizontal direction. That is, the light projecting optical waveguide 410 is configured by a bundle optical fiber 413 in which a plurality of optical fiber lines are bundled, and the light projecting optical waveguide 410 is formed by arranging the optical fiber lines of the bundle optical fiber 413 in the horizontal direction. The light receiving optical waveguide 420 is also configured by a bundle optical fiber 423, and the light receiving optical waveguide 420 is formed by arranging the optical fiber lines of the bundle optical fiber 423 in the horizontal direction. The optical fiber lines of the light projecting optical waveguide 410 and the optical fiber lines of the light receiving optical waveguide 420 are covered by an upper covering member 440 and a lower covering member 450. Although not shown in the figure, the horizontal ends in Figure 29 of the upper covering member 440 and the lower covering member 450, which sandwich the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420 from above and below, can be fixed by adhering the covering member 440 and the lower covering member 450.

[0124] 30 shows an example of limited reflection in which light is emitted from the tip of the optical waveguide. In this example, the core 411 of the light-projecting optical waveguide 410 reaches the tip of the light-projecting optical waveguide 410, and the core 421 of the light-receiving optical waveguide 420 reaches the tip of the light-receiving optical waveguide 420. Therefore, light can be emitted from the tip of the light-projecting optical waveguide 410 in the longitudinal direction of the light-projecting optical waveguide 410 and irradiated onto the workpiece WK. Light from the detection region R can be incident on the tip of the light-receiving optical waveguide 420.

[0125] 5, light is emitted from the main surface of the light-projecting optical waveguide 410 to the detection region, and the light reflected by the workpiece WK is received by the main surface of the light-receiving optical waveguide 420, but in the example shown in Fig. 30, the end face (side face) on the tip side of the light-projecting optical waveguide 410 serves as the light-projecting surface, and the end face (side face) on the tip side of the light-receiving optical waveguide 420 serves as the light-receiving surface. In this way, it is possible to use surfaces other than the main surfaces of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 as the light-projecting and light-receiving surfaces.

[0126] As shown in FIGS. 24, 26, 28, and 30, core patterns can be freely drawn within the optical waveguides 410 and 420 in addition to linear patterns, and the optical paths within the optical waveguides 410 and 420 have a high degree of freedom in design.

[0127] FIG. 31 shows another example of limited reflection in which light is emitted from the tip of the optical waveguide. In this example, light that has traveled through the core 411 of the light-emitting optical waveguide 410 can be emitted from the tip of the light-emitting optical waveguide 410 in the longitudinal direction of the light-emitting optical waveguide 410 and irradiated onto the workpiece WK. Light from the detection region R can be incident on the tip of the light-receiving optical waveguide 420. The example shown in FIG. 31 has the same optical path as in FIG. 30, but by cutting the side of the optical waveguide obliquely rather than using a pattern within the optical waveguide, it is also possible to change the optical path using the difference in refractive index between the optical waveguide and the outside.

[0128] 32, light can also be emitted and incident from the side of the optical waveguide. In this example, light that has traveled through the core 411 of the light-emitting optical waveguide 410 can be irradiated onto the workpiece WK from the side of the light-emitting optical waveguide 410. Light from the detection region R can also be incident on the side of the light-receiving optical waveguide 420. This can be achieved by the formation pattern of the cores 411, 412.

[0129] 33 shows another example of limited reflection in which light is emitted from the side of the optical waveguide. By providing a light-emitting mirror surface 432 at the tip of the light-projecting optical waveguide 410, light can be irradiated onto the workpiece WK from the side of the light-projecting optical waveguide 410. By providing a light-incident mirror surface 433 at the tip of the light-receiving optical waveguide 420, light from the detection region R can be incident on the side into the light-receiving optical waveguide 420. In this example, the formation pattern of the cores 411, 412 can remain linear.

[0130] 34 shows an example in which the optical detection unit 400 is used as a multi-point reflective optical detection unit. The optical detection unit 400 is formed with a core 411 (421) that can project light in multiple directions and receive light from multiple directions. This allows light to be projected in multiple directions from the tip of the optical detection unit 400, and light from multiple directions can be received at the tip of the optical detection unit 400. Therefore, even if there are irregularities on the surface of the workpiece WK, the effect of these irregularities can be reduced, improving detection accuracy.

[0131] 35, the tip of the light-projecting optical waveguide 410 and the tip of the light-receiving optical waveguide 420 of the light detection unit 400 may be bent. This allows light from the light-projecting optical waveguide 410 to be emitted in the bent direction, and allows light from the detection region R to be received from the bent direction of the light-receiving optical waveguide 420. Alternatively, the tip of the light-projecting optical waveguide 410 and the tip of the light-receiving optical waveguide 420 may not be bent, but may be bent in a plane according to the core pattern.

[0132] 36A shows an example of a combination of an optical waveguide and a mirror member. A light-projecting mirror member 480 is disposed opposite the tip of the light-projecting optical waveguide 410. A light-emitting mirror surface 480a is formed on the light-projecting mirror member 480, and this light-emitting mirror surface 480a allows light to be emitted upward from the light-projecting optical waveguide 410. A light-receiving mirror member 481 is disposed opposite the tip of the light-receiving optical waveguide 420. A light-incident mirror surface 481a is formed on the light-receiving mirror member 481, and this light-incident mirror surface 481a allows light to be incident on the light-receiving optical waveguide 420 from above.

[0133] 36B shows another example of a combination of an optical waveguide and a mirror member. The tip of light-projecting optical waveguide 410 and light-projecting mirror member 480 are arranged so as to abut against each other, and this configuration also allows light to be emitted upward from light-projecting optical waveguide 410 by light-emitting mirror surface 480a. Furthermore, the tip of light-receiving optical waveguide 420 and light-receiving mirror member 481 are arranged so as to abut against each other, and this configuration also allows light to be incident on light-receiving optical waveguide 420 from above.

[0134] 37 shows an example in which light emitted from the light-projecting optical waveguide 410 is irradiated onto a retroreflector 485. In this example, light reflected from the retroreflector 485 can be received at the tip of the light-receiving optical waveguide 420. If a workpiece WK is present between the retroreflector 485 and the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420, the light will be blocked by the workpiece WK, and the light will no longer be able to be received by the light-receiving optical waveguide 420. This example can be applied to a detection method that utilizes this fact.

[0135] (Transmission type optical detection unit) In the above example, the case where the present invention is applied to a detection method using limited reflection has been mainly described, but the present invention can also be used as a transmission type light detection unit 400.

[0136] 38A shows an example of a transmissive optical detection unit 400 in which the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 extend in the same direction. A light-emitting mirror surface 432 provided at the tip of the light-projecting optical waveguide 410 changes the direction of light that has traveled through the light-projecting optical waveguide 410 toward the light-receiving optical waveguide 420. The light that has been output from the light-projecting optical waveguide 410 is received by the light-receiving optical waveguide 420, has its direction changed by the light-incident mirror surface 433, and travels through the light-receiving optical waveguide 420.

[0137] 38B shows an example of the transmission type optical detection unit 400 in which the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 extend in opposite directions. As in this example, the reflection angle of the light that has traveled through the light-projecting optical waveguide 410 can be set by the light-emitting mirror surface 432, which makes it possible to detect the workpiece WK even if the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 are arranged to extend in opposite directions.

[0138] 39 shows an example in which the tip of the light-projecting optical waveguide 410 and the tip of the light-receiving optical waveguide 420 are opposed to each other. As in this example, the tip of the light-projecting optical waveguide 410 and the tip of the light-receiving optical waveguide 420 are arranged at a predetermined distance from each other, so that light emitted from the tip of the light-projecting optical waveguide 410 can be received by the tip of the light-receiving optical waveguide 420. In this case, a workpiece WK between the tip of the light-projecting optical waveguide 410 and the tip of the light-receiving optical waveguide 420 can be detected.

[0139] 40 shows an example of detecting a workpiece WK in a light detection unit 400. The light detection unit 400 is provided with an insertion section 459 for the workpiece WK, which is made up of a recess or a hole. Light that has traveled through the light-projecting optical waveguide 410 can be projected into the insertion section 459 and received at the tip of the light-receiving optical waveguide 420. When the workpiece WK is inserted into the insertion section 459, the light projected from the light-projecting optical waveguide 410 is blocked.

[0140] 41 shows an example of a transmission-type optical detection unit 400 in which multiple optical paths are formed. Light is projected from the tip of the light-projecting optical waveguide 410 so as to form multiple optical paths. Correspondingly, light from multiple optical paths can be received at the tip of the light-receiving optical waveguide 420. In this example, the detection range can be widened.

[0141] (Connector part 500) The embodiment shown in FIG. 4 has a connector unit 500, and illustrates a state before the connector unit 500 is connected to the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420. The connector unit 500 is a member that connects the base end of the light-projecting optical waveguide 410 and the base end of the light-receiving optical waveguide 420. The connector unit 500 optically connects the base end of the light-projecting optical waveguide 410 and the base end of the light-receiving optical waveguide 420 directly or indirectly to the light-projecting hole 376 and the light-receiving hole 378 of the optical sensor 1, respectively, and is a member that is detachably attached to the light-projecting hole 376 and the light-receiving hole 378. The material that constitutes the connector unit 500 may be, for example, a resin material, and the resin material is preferably a color that does not transmit light or that transmits almost no light.

[0142] 42 to 46 includes a main body 501, and a light-emitter convex portion 502 and a light-receiving convex portion 503 protruding from the main body 501. The connector 500 can integrate the light-emitter optical waveguide 410 and the light-receiving optical waveguide 420. The light-emitter convex portion 502 and the light-receiving convex portion 503 are portions that are inserted into the light-emitter hole 376 and the light-receiving hole 378 (shown in FIG. 3) of the optical sensor 1, respectively. Therefore, the distance between the light-emitter convex portion 502 and the light-receiving convex portion 503 approximately matches the distance between the light-emitter hole 376 and the light-receiving hole 378 of the optical sensor 1.

[0143] The cross section of the light-emitter-side convex portion 502 is substantially circular and surrounds the periphery of the light-emitter optical waveguide 410, and substantially coincides with the cross section of the light-emitter hole 376 of the optical sensor 1. The outer diameter of the light-emitter-side convex portion 502 is set to be larger than the thickness of the light-emitter optical waveguide 410. The outer diameter of the light-emitter-side convex portion 502 can also be set to be slightly smaller than the light-emitter hole 376 of the optical sensor 1, but the gap formed between the light-emitter-side convex portion 502 and the light-emitter-side convex portion 502 when inserted into the light-emitter hole 376 is small. This allows the light-emitter-side convex portion 502 to be positioned radially. The length of the light-emitter-side convex portion 502 corresponds to the depth of the light-emitter hole 376, and the tip surface of the light-emitter-side convex portion 502 is in contact with or close to the end surface of the reflector 380 shown in FIG. 3 when the light-emitter-side convex portion 502 is inserted into the light-emitter hole 376. The insertion depth of light-emitter-side convex portion 502 can be determined by abutting the tip surface of light-emitter-side convex portion 502 against the end surface of reflector 380. The insertion depth of light-emitter-side convex portion 502 can also be determined by pressing main body portion 501 against a part of optical sensor 1.

[0144] The light-receiving side convex portion 503 is configured similarly to the light-emitting side convex portion 502, and is a substantially circular shape that surrounds the periphery of the light-receiving optical waveguide 420. When the light-receiving side convex portion 503 is inserted into the light-receiving hole 378 of the optical sensor 1, it is positioned in the radial direction and the insertion direction.

[0145] As shown in FIG. 44 , the main body 501 is formed with a light guide insertion hole 501a into which the base end of the light guide 401 is inserted. An elastic material 504 made of rubber, elastomer, or the like is provided between the base end of the light guide 401 and the inner surface of the light guide insertion hole 501a. The elastic material 504 is formed to cover the outer peripheral surface of the base end of the light guide 401. A plurality of engaging protrusions 504a are formed on the elastic material 504. The main body 501 is formed with engaging holes 501b into which the engaging protrusions 504a of the elastic material 504 engage. When the engaging protrusions 504a of the elastic material 504 are engaged with the engaging holes 501b of the main body 501, the elastic material 504 is prevented from coming off the main body 501. Note that the elastic material 504 may be omitted.

[0146] The light-projecting optical waveguide 410 of the light-guiding unit 401 passes through the light-projecting-side convex portion 502. As in the first example shown in FIG. 47 , the tip of the light-projecting optical waveguide 410 reaches the tip surface of the light-projecting-side convex portion 502 and is exposed at the tip surface. The tip of the light-projecting optical waveguide 410 and the tip surface of the light-projecting-side convex portion 502 may be flush with each other, or the tip of the light-projecting optical waveguide 410 may be recessed from the tip surface of the light-projecting-side convex portion 502. If the tip of the light-projecting optical waveguide 410 is recessed, damage to the tip of the light-projecting optical waveguide 410 can be prevented. Furthermore, if the tip of the light-projecting optical waveguide 410 is recessed, it is preferable to set the distance between the tip of the light-projecting optical waveguide 410 and the tip surface of the light-projecting-side convex portion 502 to 0.5 mm or less. This is to prevent a decrease in the amount of light.

[0147] As shown in FIG. 48 , light-emitter-side convex portion 502 has a concave light-emitter-side accommodation portion 502a formed therein to accommodate light-emitter optical waveguide 410. Light-emitter-side accommodation portion 502a is open on the outer peripheral surface of light-emitter-side convex portion 502. Light-emitter-side accommodation portion 502a is provided with a pressing member 505 for pressing down and holding light-emitter optical waveguide 410. Pressing member 505 engages with the inner surface of light-emitter-side accommodation portion 502a to hold it in a predetermined position, thereby determining the relative position of light-emitter optical waveguide 410 with respect to light-emitter-side convex portion 502. Therefore, when light-emitter-side convex portion 502 is inserted into light-emitter hole 376 of optical sensor 1, it positions the tip of light-emitter optical waveguide 410 at the center position of the light emission surface of light-emitting element 104 shown in FIG. The pressing member 505 may be omitted and the light projection optical waveguide 410 may be bonded to the inner surface of the light projection side housing portion 502a.

[0148] The light-receiving side convex portion 503 is also formed with a concave light-emitter side housing portion 503a that houses the light-receiving optical waveguide 420. The light-receiving side housing portion 503a is open on the outer peripheral surface of the light-receiving side convex portion 503. The light-receiving side housing portion 503a is provided with a pressing member 506 that presses down and holds the light-receiving optical waveguide 420. The pressing member 506 engages with the inner surface of the light-receiving side housing portion 503a to hold it in a predetermined position, thereby determining the relative position of the light-receiving optical waveguide 420 with respect to the light-receiving side convex portion 503. Therefore, when the light-receiving side convex portion 503 is inserted into the light-receiving hole 378 of the optical sensor 1, the light-receiving side convex portion 503 positions the tip of the light-receiving optical waveguide 420 at the center of the light-receiving surface of the light-receiving element 204 shown in FIG. 3 .

[0149] 49 shows a connector section 500 according to a second example of the present embodiment. A main body 510 of the connector section 500 of the second example is composed of an upper member 511 and a lower member 512. The upper member 511 and the lower member 512 may be integrated with screws or the like, or may be integrated with an adhesive or the like.

[0150] Lower member 512 is formed with a first groove 512a that holds light-projecting optical waveguide 410 protected by protective elastic material 513, and a second groove 512b that holds light-receiving optical waveguide 420 protected by protective elastic material 514. Upper member 511 is formed with a first fitting portion 511a that fits into first groove 512a, and a second fitting portion 511b that fits into second groove 512b. By fitting the first fitting portion 511a into the first groove portion 512a, the light-emitting optical waveguide 410 can be sandwiched and held between the tip surface of the first fitting portion 511a and the bottom surface of the first groove portion 512a, and by fitting the second fitting portion 511b into the second groove portion 512b, the light-receiving optical waveguide 420 can be sandwiched and held between the tip surface of the second fitting portion 511b and the bottom surface of the second groove portion 512b.

[0151] Furthermore, third fitting portion 511c that fits into light-emitter side accommodating portion 502a and fourth fitting portion 511d that fits into light-emitter side accommodating portion 503a are formed in upper member 511. Third fitting portion 511c and fourth fitting portion 511d are portions that replace holding members 505 and 506 of the first example, and can hold down light-emitter optical waveguide 410 and light-receiving optical waveguide 420 by third fitting portion 511c and fourth fitting portion 511d.

[0152] FIG. 50 shows a connector unit 500 according to a third example of this embodiment. In the connector unit 500 of the third example, a main body 520, a light-emitter-side convex portion 522, and a light-receiving-side convex portion 523 are configured as separate members. The light-emitter-side convex portion 522 and the light-receiving-side convex portion 523 are each configured as a rod-shaped member. The light-emitter-side convex portion 522 is configured as a base member 522a having a partially cutout shape and a fitting member 522b that fits into the cutout portion. By arranging the light-emitter optical waveguide 410 in the cutout portion of the base member 522a, it is possible to position the light-emitter optical waveguide 410 relative to the base member 522a. With the light-emitter optical waveguide 410 positioned, by fitting the fitting member 522b into the cutout portion of the base member 522a, it is possible to hold the light-emitter optical waveguide 410 immovably. The light-receiving side convex portion 523 is similarly configured and includes a base member 523a and a fitting member 523b.

[0153] 51 , main body 520 is formed with light-emitter-side holding hole 520a into which light-emitter-side convex 522 is inserted and held, and light-receiving-side holding hole 520b into which light-receiving-side convex 523 is inserted and held. With light-emitter-side convex 522 inserted into light-emitter-side holding hole 520a, light-emitter-side convex 522 can be rotated around its center line. Similarly, light-receiving-side convex 523 can be rotated. Main body 520 can be made of rubber or the like. Main body 520 may be omitted.

[0154] 52, a pre-installation adapter 540 may be provided in advance in the optical sensor 1. In this example, the light detection unit 400 can be connected to the optical sensor 1 via the pre-installation adapter 540.

[0155] 53, the shapes of the insertion openings 376a, 378a of the light-projecting hole 376 and the light-receiving hole 378 of the optical sensor 1 may be slit-shaped. These slit-shaped insertion openings 376a, 378a substantially match the cross-sectional shapes of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420, and therefore the base ends of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 can be directly connected to the light-projecting hole 376 and the light-receiving hole 378 without providing a connector section 500.

[0156] 54 shows light-emitter connector section 550 and light-receiving connector section 551 according to a fourth example of the embodiment. Light-emitter connector section 550 is formed in a cylindrical shape that can be inserted into light-emitter hole 376 of optical sensor 1 and positioned therein. Light-emitter connector section 550 is formed with a slit-like hole 550a into which light-emitter optical waveguide 410 is inserted. Light-receiving connector section 551 is similarly configured, and is formed in a cylindrical shape that can be inserted into light-receiving hole 378 of optical sensor 1 and positioned therein, and has slit-like hole 551a.

[0157] The light-emitting side connector portion 550 and the light-receiving side connector portion 551 are inserted all the way into the light-emitting hole 376 and the light-receiving hole 378 of the optical sensor 1, and the light-emitting optical waveguide 410 and the light-receiving optical waveguide 420 are inserted all the way into the holes 550a and 551a, respectively, thereby enabling connection to the optical sensor 1.

[0158] (Configuration of relay section) 55A, 55B, 55C, 56A, and 56B, light projecting optical waveguide 410 and light receiving optical waveguide 420 can be connected to the bundle optical fiber by relay connector 580. Relay connector 580 is a member that integrally bundles light projecting side optical fiber 560, which is connected to the base end of light projecting optical waveguide 410 and optically coupled to light projecting hole 376 of optical sensor 1 in a removably insertable manner, and light receiving side optical fiber 561, which is connected to the base end of light receiving optical waveguide 420 and optically coupled to light receiving hole 378 of optical sensor 1 in a removably insertable manner. Light projecting side optical fiber 560 and light receiving side optical fiber 561 are formed by a bundle optical fiber formed by bundling a plurality of optical fiber wires.

[0159] The relay connector section 580 can be used when extending the light detection unit 400. The relay connector section 580 includes a connector case 581 made of a resin material or the like that does not transmit light or transmits almost no light. The light-emitting side optical fiber 560 and the light-receiving side optical fiber 561 are held by fiber adapters 560b and 561b with the optical fiber lines 560a and 561a aligned horizontally (in the width direction of the optical waveguides 410 and 420), respectively. The fiber adapters 560b and 561b are fixed in a state housed in the connector case 581. Within the connector case 581, the light-emitting side and the light-receiving side are optically isolated from each other.

[0160] A light-projecting side adapter 490 and a light-receiving side adapter 491 are attached to the base ends of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420, respectively. The light-projecting side adapter 490 and the light-receiving side adapter 491 are housed in and fixed in a connector case 581.

[0161] The arrangement direction of optical fiber lines 560a constituting light projecting side optical fiber 560 coincides with the width direction of light projecting optical waveguide 410, and optical fiber lines 560a are arranged from a portion corresponding to one width direction end to a portion corresponding to the other width direction end of light projecting optical waveguide 410. Similarly, on the light receiving side, the arrangement direction of optical fiber lines 561a coincides with the width direction of light receiving optical waveguide 420, and optical fiber lines 561a are arranged from a portion corresponding to one width direction end to a portion corresponding to the other width direction end of light receiving optical waveguide 420.

[0162] A light-projecting side rod lens 582 that is long in the width direction of the light-projecting side optical fiber 560 is provided between the tip end of the light-projecting side optical fiber 560 and the base end of the light-receiving side optical waveguide 410. A light-receiving side rod lens 583 that is long in the width direction of the light-receiving side optical waveguide 420 is provided between the tip end of the light-receiving side optical fiber 561 and the base end of the light-receiving side optical waveguide 420. A transparent elastic material or adhesive may be used instead of the light-projecting side rod lens 582 and the light-receiving side rod lens 583. Alternatively, the light-projecting side rod lens 582 and the light-receiving side rod lens 583 may be omitted, and the tip end of the light-projecting side optical fiber 560 may be butted against the base end of the light-projecting side optical waveguide 410, or the tip end of the light-receiving side optical fiber 561 may be butted against the base end of the light-receiving side optical waveguide 420. Note that a single core may be used instead of using multiple optical fiber wires.

[0163] Furthermore, the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 do not have to be integrated into one case 581, but may be separated into the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420.

[0164] Furthermore, light leaking from the coupling between the tip of light-projecting optical fiber 560 and the base end of light-projecting optical waveguide 410 can be used as an operation indicator, and light leaking from the coupling between the tip of light-receiving optical fiber 561 and the base end of light-receiving optical waveguide 420 can be used as output indicator 585 (shown in FIG. 55A).

[0165] 55A, indicator light 585 is provided on the light-receiving side, but it may also be provided on the light-emitting side. The light source of the indicator light may be LED 212 shown in FIG. 3, or it may be light emitted from light-emitting element 104 used for detection or light that is reflected by workpiece WK. The indicator light may be realized by cutting a part of the surface of the optical waveguide, but loss of detection light can be reduced by making good use of the leaked light that occurs at the coupling end faces of optical waveguides 410, 420 and optical fibers 560, 561 as an indicator light.

[0166] 55A and 55B, a through hole 588 may also be provided in relay connector 580. Of through holes 588 of relay connector 580, the through hole on the tip side communicates with a through hole provided between optical waveguides or within an optical waveguide.

[0167] Further, a reinforcing plate 461 is provided at the tip end of the optical waveguides 410 and 420. The reinforcing plate 461 is preferably made of metal or resin and is thin and strong. Furthermore, by attaching the reinforcing plate 461 to the lower covering member 450 with adhesive or double-sided tape, bending and deformation of the tip detection portion can be suppressed.

[0168] The reinforcing plate 461 may be provided only on the rear surface, only on the front surface, or on both surfaces of the optical waveguides 410 and 420. In Fig. 56, the reinforcing plate 461 is provided only on the rear surfaces of the optical waveguides 410 and 420. The surfaces on which the reinforcing plate 461 is provided are not limited to the main surfaces of the optical waveguides 410 and 420, and the end surfaces on three sides of the detection unit may also be surrounded by the reinforcing plate 461. The reinforcing plate 461 is wider than the optical waveguides 410 and 420 or the sheet-like covering member.

[0169] The reinforcing plate 461 may also be provided with holes that communicate with the third through-hole 404 and the fourth through-hole 405 of the optical waveguides 410 and 420. These holes may be used as fixing holes for screws.

[0170] The method of fixing the reinforcing plate 461 is not limited to screw fastening, but the reinforcing plate 461 can also be fixed by adhesive, double-sided tape, or by sandwiching.

[0171] Although not shown, characters can be written on the front and back of the tape of relay connector case 581 or optical waveguides 410 and 420 by stickers, silk printing, engraving, or the like for display identification.

[0172] 55A to 55C have been used to explain the general shape of relay connector 581, and now, using Fig. 56B, a brief description will be given of an assembly method for optically coupling optical waveguides 410, 420 and optical fibers 560, 561 at relay connector 581. By adopting the configuration shown in Fig. 56B, the tip end of light-receiving-side optical fiber 561 and the base end of light-receiving optical waveguide 420 can be efficiently butted against each other. (Configuration of the relay connector in Figure 56B) 1. The coatings at the ends of the optical fibers 560 and 561 (fiber bundle) are stripped, and the fiber bundles are aligned in a row in the fiber adapters 560b and 561b. 2. The optical waveguides 410 and 420 are attached to each other with tape to determine the pitch in the width direction, and the coupling portions with the optical fibers 560 and 561 are slightly protruded. 3. Fit the fiber adapters 560b and 561b into the connector case 581 and position them in the width direction using the positioning bosses (on the oval). 4. Fit the optical waveguides 410 and 420 into the connector case 581 and position them in the width direction using the positioning bosses (on the oval). 5. Move the fiber adapters 560b, 561b and the optical waveguides 410, 420 fitted into the connector case 581 in the longitudinal direction, and fix the bases of the fiber adapters 560b, 561b and the optical waveguides 410, 420 with a hard adhesive so that the optical coupling end faces are butted together or a small gap remains, and fix the optical coupling portion by filling the coupling gap with a transparent elastic material or adhesive. 6. Finally, close the lid of the connector case 581. At this time, use adhesive, double-sided tape, or welding to prevent the lid from opening.

[0173] 57 and 58, relay connector section 590 can also be configured with three parts. Relay connector section 590 includes a first holding member 591 that holds light projecting side optical fiber 560 and light receiving side optical fiber 561, a second holding member 592 that holds light projecting optical waveguide 410 and light receiving optical waveguide 420, and an intermediate member 593 that is arranged between first holding member 591 and second holding member 592.

[0174] 58, first holding member 591 has holding holes 591a and 591b formed therein, into which the tip ends of light projecting side optical fiber 560 and light receiving side optical fiber 561 are inserted and held. Second holding member 592 has holding holes 592a and 592b formed therein, into which the base ends of light projecting optical waveguide 410 and light receiving optical waveguide 420 are inserted and held.

[0175] First holding member 591, intermediate member 593, and second holding member 592 are integrated together by screw 594. That is, screw 594 passes through first holding member 591 and intermediate member 593 from the first holding member 591 side, and then screws into second holding member 592. The position of screw 594 is not limited to the position shown in Fig. 58 , and for example, as in a third example of a relay portion shown in Fig. 59 , if the interval between light projecting side optical fiber 560 and light receiving side optical fiber 561 is wide, screw 594 can be provided between light projecting side optical fiber 560 and light receiving side optical fiber 561.

[0176] Furthermore, the optical fibers 560 and 561 extending from the relay connector 580 may be free-cut optical fibers. For free-cut optical fibers, the length of the optical fiber can be adjusted by using a free-cut jig.

[0177] In addition, in the first to third examples of the relay portion, if a small-diameter optical fiber is used as the optical fiber 560, 561 extending from the relay connector portion 580 to the optical sensor 1 side, an adapter for connecting the optical fiber to the optical sensor 1 may be used to facilitate optical coupling.

[0178] Any fiber diameter can be used for the optical fibers 560 and 561. As with the tip of the optical waveguide, a thin relay connector 580 is also desired to increase the flexibility of installation space. If the diameter of the optical fiber is large, the thickness of the relay connector 580 increases accordingly. Therefore, it is better to have as small a fiber diameter as possible, but there is also design freedom that allows for free design in consideration of the coupling efficiency with the optical waveguide.

[0179] In this embodiment, as shown in FIGS. 6 and 8, the core 411 has been described as having one layer, but the present invention is not limited to this, and the core 411 may have two or more layers.

[0180] 1, when optical sensor 1 is installed upright with display unit 334 facing upward, light projection hole 376 and light reception hole 378 are aligned vertically relative to housing 10, and the light projection path and light reception path of the optical waveguide are aligned horizontally in the sheet-like direction. Therefore, two paths aligned vertically are aligned horizontally, and a twisting section is required between optical sensor 1 and the tip of the optical waveguide to align the paths horizontally. Twisting a thin, linear optical fiber is easier than twisting a sheet-like optical waveguide, and this reduces breakage, light leakage, and loss.

[0181] (Effects of the embodiment) According to this embodiment, the optical waveguides 410, 420 are formed in a sheet shape that is wide in the horizontal direction, and have cores 411, 421 and clads 412, 422 that are arranged in layers in the vertical direction, so it is possible to ensure the amount of light in the optical waveguides 410, 420 while thinning the optical waveguides 410, 420. The clads 412, 422 of the optical waveguides 410, 420 are covered with sheet-like covering members 440, 450, and these covering members 440, 450 serve as installation surfaces for the installation target, so the thin optical waveguides 410, 420 can be easily installed on the installation target.

[0182] Furthermore, the optical waveguides 410 and 420 can be connected to the optical sensor 1 by a connector section 500. The connector section 500 is detachably attached to the optical sensor 1, which makes it easy to connect the light detection unit 400 to the optical sensor 1 as needed, and to replace the light detection unit 400, etc.

[0183] Furthermore, the light detection unit 400 has a light emitting and receiving side that are integrated with a covering member, a connector section, a relay connector section, etc., making it easy to handle as a unit.

[0184] The above-described embodiments are merely examples in all respects and should not be construed as limiting. Furthermore, all modifications and variations within the scope of the claims are within the scope of the present invention. [Industrial Applicability]

[0185] As described above, the present invention can be used to detect the presence or absence of an article, for example. [Explanation of symbols]

[0186] 1 Optical sensor 104 Light-emitting element 204 Photodetector 308a Signal generation section 376 Light projection hole (light projection connection part) 378 Light receiving hole (light receiving connection part) 400 Photodetector Unit 402~405 1st~4th insertion hole (fixed part) 410 Light guide for projection 411 cores 412 Clad 420 Optical waveguide for light reception 421 cores 422 Clad 440 Upper covering member 430 Light extraction member 432 Light exit mirror surface (light exit part) 433 Light incident mirror surface (light incident part) 450 Lower covering member 461 Reinforcing plate (reinforcing metal) 500 Connector part 502 Light-emitting side convex part 503 Light receiving side convex part 560 Light-emitting optical fiber 560a fiber optic cable 561 Receiving optical fiber 561a fiber optic cable 582 Light-emitting rod lens 583 Receiving rod lens 585 Indicator light 588 Through hole in intermediate connector

Claims

1. an optical detection unit that is insertably connected to an optical sensor that has a light-emitting element that emits detection light toward a detection area, a light-receiving element that receives the detection light from the detection area, a light-emitting hole for optically coupling to the light-emitting element, and a light-receiving hole for optically coupling to the light-receiving element, and that compares a light-receiving signal generated by the light-receiving element with a threshold value to determine the presence or absence of an article in the detection area, The light detection unit a connector portion detachably attached to the light-emitting hole and the light-receiving hole of the optical sensor; an optical waveguide having a base end optically connected to the connector portion and a tip end serving as a light-emitting end and a light-receiving end of the optical sensor, the optical waveguide including a core and a clad provided in layers to guide light between the base end and the tip end; and The optical waveguide is a light-projecting optical waveguide whose base end is optically coupled to the light-emitting element of the optical sensor via the connector portion and whose tip end projects the detection light onto the detection area; a light-receiving optical waveguide whose base end is optically coupled to the light-receiving element of the optical sensor via the connector portion and whose tip end receives the detection light from the detection region; Equipped with a light detection unit characterized in that each of the light projecting optical waveguide and the light receiving optical waveguide has a wide sheet shape in which a plurality of the cores are arranged at intervals along the direction in which the light projecting optical waveguide and the light receiving optical waveguide are arranged, and the cladding is arranged to surround the plurality of cores.

2. 2. The optical detection unit according to claim 1, The connector portion is a light detection unit having a protrusion that is inserted into the light-emitting hole or the light-receiving hole.

3. 3. The optical detection unit according to claim 2, the base end of the optical waveguide is exposed on a tip end surface of the protrusion, The protrusion is an optical detection unit that positions the base end at the center of the light emission surface of the light emitting element or the light receiving surface of the light receiving element when inserted into the light projecting hole or the light receiving hole.

4. 2. The optical detection unit according to claim 1, The connector portion is an optical detection unit that integrally bundles together a light-projecting side optical fiber that is connected to the base end of the light-projecting optical waveguide and optically coupled to the light-projecting hole in a manner that allows it to be inserted and removed, and a light-receiving side optical fiber that is connected to the base end of the light-receiving optical waveguide and optically coupled to the light-receiving hole in a manner that allows it to be inserted and removed.

5. 5. The optical detection unit according to claim 4, The light-emitting optical fiber and the light-receiving optical fiber are optical fiber bundles each made up of a plurality of optical fiber wires.

6. 6. The optical detection unit according to claim 5, The connection side of the light-projecting side optical fiber with the light-projecting optical waveguide is an optical detection unit in which the multiple optical fiber lines constituting the light-projecting side optical fiber are arranged side by side in the width direction of the light-projecting optical waveguide.

7. 7. The optical detection unit according to claim 6, The light detection unit has a rod lens, a transparent elastic material, or a transparent adhesive material that is long in the width direction of the light projection optical waveguide, provided between the light projection side optical fiber and the light projection optical waveguide.

8. 8. The optical detection unit according to claim 4, The light-emitting optical fiber and the light-receiving optical fiber are optically coupled to the light-emitting optical waveguide and the light-receiving optical waveguide in a light detection unit located within the connector portion.

9. 9. The optical detection unit according to claim 1, The optical detection unit has an indicator light provided between the base end and the tip end of the optical waveguide to extract light passing through the core of the optical waveguide to the outside.

10. 10. The optical detection unit according to claim 1, the light-projecting hole and the light-receiving hole are circular holes, In the optical detection unit, the portion of the connector section that is detachably attached to the light-projecting hole or the light-receiving hole is a portion where cores of the optical waveguide are arranged in a sheet shape.

11. 11. The optical detection unit according to claim 1, The connector portion of the light detection unit has a through hole for fixing the connector portion to an object to which the light detection unit is attached.

12. 12. The optical detection unit according to claim 1, a covering member covering the optical waveguide; The cover member has a hole for fixing the light detection unit to an object to which the light detection unit is attached.

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