Light 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 related to the presence or absence of an article as a result of the comparison (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 of Patent Document 1 is made 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 in which multiple optical fiber wires are bundled together, 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 space between components where only a thin space can be secured, or where it needs to be installed in such a thin space. In these cases, the bundle optical fiber of Patent Document 1 has a large outer diameter and is difficult to handle.

[0007] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to enable an 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-projecting 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 generating portion that compares a light-receiving signal generated by the light-receiving element with a threshold value and generates a detection signal indicative of the comparison result.

[0009] The light detection unit has an optical waveguide and a connector section. The optical waveguide is a sheet-like member that guides light between a first end and a second end and is wide in the horizontal direction, has a core and a clad surrounding the core, and the core and the clad are arranged in layers in the vertical direction, the first end is connected to a light-projecting connection section or a light-receiving connection section so as to be optically coupled to the light-emitting element or the light-receiving element of the optical sensor, and the second end is a light-projecting end or a light-receiving end that projects light to a detection area or receives light from the detection area. The connector section 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-projecting connection section or the light-receiving connection section of the optical sensor, and is detachably attached to the light-projecting connection section or the light-receiving connection section.

[0010] According to this configuration, the optical waveguide is in the form of a sheet that is wide in the horizontal direction and has a core and a clad that are arranged in layers in the vertical direction, so that it is possible to ensure the amount of light in the optical waveguide while making the optical waveguide thin. The first end of the optical waveguide can be connected to the light projecting connection part or the light receiving connection part of the optical sensor by the connector part. The connector part is detachably attached to the light projecting connection part or the light receiving connection part, so that it is easy to connect the optical detection unit to the optical sensor as needed and to replace the optical detection unit.

[0011] In the second aspect of the present disclosure, the connector portion can have a convex portion to be 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 projecting connection part or the light receiving connection part by inserting the convex part of the connector part into the light projecting connection part or the light receiving connection part. The convex part may be provided on both the light projecting side and the light receiving side, and by integrating the convex part on the light projecting side and the convex part on the light receiving side, the connection work becomes 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-emitter connection portion or the light-receiver 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 a 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] According to this configuration, since the first end of the optical waveguide is exposed on the tip surface of the convex portion, it is possible to optically couple the optical waveguide to the light emitting element or the light receiving element by inserting the convex portion into the light projecting connection portion or the light receiving connection portion. At this time, since the first end of the optical waveguide is positioned at the center position of the light emitting surface of the light emitting element or the light receiving surface of the light receiving element, it is possible to suppress a decrease in the amount of light at the connection portion.

[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 and having the second end serving as a light-projecting end for projecting light to a detection area, and a light-receiving optical waveguide connected to the light-receiving connection portion of the optical sensor and having the second end serving as a light-receiving end for receiving light from the detection area. The connector portion may be a member that integrally bundles together a light-projecting side 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 an insertable and removable manner, and a light-receiving side 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 an insertable and removable manner.

[0017] According to this configuration, the first end of the light projecting optical waveguide can be connected to the light projecting connection part via the light projecting optical fiber, and the first end of the light receiving optical waveguide can be connected to the light receiving connection part via the light receiving optical fiber. At this time, 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 serve as relay members, even if the shapes of the optical path end faces of the light projecting optical waveguide and the light receiving optical waveguide are different from the shapes of the light projecting connection part and the light receiving connection part of the optical sensor, it can be easily accommodated. Furthermore, even if the interval between the light projecting optical fiber and the light receiving optical fiber is determined by the requirements of the optical sensor, the interval between the light projecting optical waveguide and the light receiving optical waveguide beyond the connector can be freely set and can 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 can 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 constituted by a bundle optical fiber, the end face shape is close to circular, whereas the light projecting optical waveguide is wide in the horizontal direction, and the difference in shape of the connection portion between the two becomes large, which may result in increased light loss. In this configuration, the multiple fiber lines constituting the light projecting side optical fiber are arranged side by side in the width direction of the light projecting optical waveguide, so that the difference in shape of the connection portion between the light projecting side optical fiber and the light projecting optical waveguide is small, and light loss can be reduced.

[0021] Incidentally, 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] In 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 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-projecting hole that is optically coupled to a light-projecting 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 arranged to project detection light toward the detection area, and 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 arranged to receive detection light from the detection area, and 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 on the connector portion, having a substantially circular cross section that surrounds the sensor side end of the first optical waveguide and having substantially the same size as the light projecting hole; and a light receiving side convex portion provided on the connector portion, having a substantially circular cross section that surrounds the sensor side end of the second optical waveguide and having substantially the same size as the light receiving hole.

[0026] That is, since the first optical waveguide and the second optical waveguide are sheet-shaped, it is possible to ensure the amount of light in the optical waveguide while making the optical waveguide thin. When connecting the light detection unit to the optical sensor, the light-projecting side convex portion integrated with the connector is simply inserted into the light-projecting hole of the optical sensor, which improves workability during connection. When the light-projecting side convex portion is connected, it is positioned within the light-projecting hole because the light-projecting side convex portion is approximately the same size as the light-projecting hole. The light-receiving side convex portion is also positioned in the same manner. 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 made larger than a thickness dimension of the first optical waveguide.

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

[0029] The light projecting hole and the light receiving hole of the optical sensor may be arranged in a vertical direction with respect to a housing, the light projecting path and the light receiving path of the optical waveguide may be arranged in a horizontal direction of 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 a core of the optical waveguide to the outside may be provided on the light-emitting side or the light-receiving side optical waveguide between a first end and a 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 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 side and the light-receiving side 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. Effect of the Invention

[0034] As described above, the optical waveguide, in which the core and the clad are arranged in layers in the vertical direction, is in the form of a wide sheet in the horizontal direction, so that the optical waveguide can be passed through a thin space or installed in a thin space while ensuring the amount of light in the optical waveguide. Since the connector part is detachably attached to the light-emitter connection part or the light-receiver connection part, it is easy to connect the optical detection unit or replace the optical detection unit. [Brief description 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. [Diagram 2] FIG. 2 is a block diagram of the optical sensor. [Diagram 3] FIG. 3 is a vertical sectional perspective view for explaining the element holder and a member held by the element holder. [Figure 4]FIG. 4 is a plan view showing a state in which the light guide section and the connector section of the light detection unit are separated. [Diagram 5] FIG. 5 is a perspective view of the light-guiding portion of the light-detecting unit with the upper cover member 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 an end portion 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 guiding 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 the 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 by a screw. [Figure 17] FIG. 17 is a vertical sectional view showing an example in which the light detection unit is directly fixed to the mounting member by a screw. [Figure 18] FIG. 18 is a perspective view showing an example in which a covering member is provided on a fixed portion of a 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 a 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 a 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 fixing portion of a light detection unit, and a 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 realize limited reflection. [Diagram 25] FIG. 25 is a perspective view showing a configuration example in which a reflector made of a separate member is provided at the tip of the light-projecting optical waveguide and the light-receiving optical waveguide to realize 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 reduction in optical loss. [Figure 27A] FIG. 27A is a diagram showing an example in which a light output mirror surface is provided on the tip surface of a light projection optical waveguide. [Figure 27B] FIG. 27B is a diagram showing an example in which the direction of the tip 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-leading optical waveguide and the light-receiving optical waveguide are configured by arranging a plurality of optical fibers in the horizontal direction. [Diagram 30] FIG. 30 is a plan view showing an example of limited reflection for emitting light from the tip of an optical waveguide. [Diagram 31] FIG. 31 is a plan view showing another example of limited reflection for emitting light from the tip of an optical waveguide. [Diagram 32] FIG. 32 is a plan view showing an example of limited reflection in which light is emitted from a side surface of an optical waveguide. [Diagram 33] FIG. 33 is a plan view showing another example of limited reflection in which light is emitted from a side surface of an optical waveguide. [Diagram 34] FIG. 34 is a plan view showing an example of use as a multipoint reflection type light detection unit. [Diagram 35] FIG. 35 is a diagram showing an example in which the tip end portion of the 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 a light leading optical waveguide and a 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 leading 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 a light leading optical waveguide and the tip of a light receiving optical waveguide are opposed to each other. [Diagram 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. [Diagram 41] FIG. 41 is a diagram showing an example of a transmission type photodetection unit in which multiple optical paths are formed. [Diagram 42] FIG. 42 is a plan view of the connector portion according to the first example. [Diagram 43] FIG. 43 is a side view of the connector portion according to the first example. [Diagram 44] FIG. 44 is a cross-sectional view taken along line AA in FIG. [Diagram 45] FIG. 45 is a cross-sectional view taken along line BB in FIG. [Diagram 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 on which the pressing member is provided. [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 a connector portion according to the third example, as viewed from the tip end side. [Figure 52] FIG. 52 is a diagram showing an example in which a pre-installation adapter is provided. [Diagram 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 the 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 PREFERRED EMBODIMENTS

[0036] Hereinafter, the 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 illustrative 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 to which an optical detection unit 400 according to an embodiment of the present invention is connected is in use. An optical detection device 300 is configured by the optical detection unit 400 and the optical sensor 1. 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, and one of the optical detection devices 300 is illustrated 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 unit and the others are child units. For example, when the parent unit finishes projecting light, the parent unit supplies a signal to the first child unit to start projecting light, and the first child unit starts projecting light. When the first child unit finishes projecting light, the first child unit supplies a signal to the second child unit to start projecting light, and the second child unit starts projecting light. Then, the third and fourth child units 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 the optical detection device 300 in FIG. 2, the optical sensor 1 constituting the optical detection device 300 includes a light projecting section 102 and a light receiving section 202. The light projecting section 102 outputs a predetermined pulsed light to the light detection unit 400. The light emitting element 104 of the light projecting section 102 is driven by an oscillation pulse supplied from a light projecting power supply control circuit 302 to emit a pulsed light. Meanwhile, the light received by the light receiving section 202 is photoelectrically converted by the light receiving element 204 and is sent to the control section 308 via the light receiving element amplifier circuit 206, the amplifier circuit 304, and the A / D converter 306. As a result, detection is performed in synchronization with the pulsed light, and the detection signal is further converted into a DC signal or the like, and then output as an ON / OFF signal representing the detection result from the I / O circuit 360 constituting the interface section.

[0041] The optical sensor 1 includes a light projecting circuit 106 for driving a light emitting element 104. The light emitting element 104 is a member 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 thereto.

[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 amount of light emitted, 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 transmits the amount of light received to an LED light-emission amount monitor circuit 312 via a monitor line. The LED light-emission amount monitor circuit 312 supplies a light-receiving amount signal converted into a digital signal via an A / D converter 314 to a control unit 308. The control unit 308 controls the light-projecting power supply control circuit 302 based on the amount of light emitted detected by the monitor light-receiving element 110 so that the amount of light emitted becomes a predetermined value, and performs feedback control to drive the light-emitting element 104 by adjusting the amount of current of the light-projecting APC circuit 108.

[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 member that receives detection light from a 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, sent to an amplifier circuit 304, and then amplified by the controller amplifier circuit 304. The analog signal amplified by the controller amplifier circuit 304 is converted to a digital signal via an A / D converter 306 and input to a signal generating unit 308a of a control unit 308. The signal generating unit 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 generating unit 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, 8 (shown in FIG. 1) which are a user interface for accepting setting value adjustments are connected, and an I / O circuit 360 for inputting and outputting with 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, an FPGA, an ASIC, etc. Each of the various circuits (reference numbers 108, 114, 206, 214, 302, 304, 306, 312, 314, 320, 328, 330, 332, 360) may be configured from an IC, or the various circuits may be configured from one IC, or the control unit 308 and the various circuits may be configured from one 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 located on the top when in the usage state shown in Fig. 1 is called the "top", but this is defined merely for the sake of convenience of explanation, 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 detection value (amount of received light), threshold value, etc. are displayed using the display unit 334. The display unit 334 may be configured with seven-segment displays arranged side by side.

[0048] 1, operation buttons such as an up / down button 6, a mode button 8, and a set button 9 are disposed adjacent to a 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 indicating the current output or detection state, reference numeral 16a denotes an operation indicator light for the first channel, and reference numeral 16b denotes an operation indicator light for the second channel.

[0049] By operating the above 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 the threshold value are displayed as is, and a conversion display mode in which the detection value (amount of received light for display) and the threshold value for display converted by the display conversion rate or the display conversion formula are displayed, and it is also possible to set the sensitivity, the threshold value, etc. In addition, since the display object, display mode, display switching operation, and display mode switching of the optical sensor 1 are described in detail in JP 2006-351380 and JP 2019-61885, the description thereof will be omitted by citing the specifications of JP 2006-351380 and JP 2019-61885.

[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 the LED 212 as a light display light emitting element. In this embodiment, the light emitting element 104 and the light receiving element 204 are arranged in the vertical direction, and specifically, the light emitting element 104 is located above the light receiving element 204, but the light receiving element 204 may be located above the light emitting element 104, or the light emitting element 104 and the light receiving element 204 may be arranged in the left-right direction (horizontal direction).

[0051] The element holder 368 has a light projection hole 376 and a light receiving hole 378 to which the light detection unit 400 is connected. The light projection hole 376 and the light receiving hole 378 are configured as through holes having a circular cross section, and are formed to penetrate the element holder 368. The light projection hole 376 constitutes a light projection connection portion for optically coupling to the light emitting element 104 by directly or indirectly connecting to a light projection 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 projection optical waveguide 410 and the light receiving optical waveguide 420 will be described later.

[0052] That is, ends of light projecting hole 376 and light receiving hole 378 have first insertion opening 376a and second insertion opening 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. The position of light emitting element 104 is set 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 side of the light receiving hole 378. The light receiving element 204 is mounted on a light receiving mounting board 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 portion on the back side of the light receiving hole 378.

[0054] (Clamp mechanism) The optical sensor 1 has a clamp mechanism for clamping the light detection unit 400 in a connected state. The clamp 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 projection hole 376 and the light reception 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 projection hole 376 and the light reception hole 378 are clamped by the clamp mechanism, the inserted portions are prevented from coming out of the light projection hole 376 and the light reception hole 378.

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

[0056] The configuration of the clamp mechanism and operating lever 7 is not limited to the above-mentioned configuration, but may be any configuration that can clamp the portion inserted into light projecting hole 376 and light receiving hole 378 in 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 a workpiece WK by limited reflection is a type of sensor that detects whether or not the workpiece WK is present at a specified position by limiting the detection area of ​​the object, irradiating detection light, and receiving the reflected light reflected by the workpiece WK in the detection area with a light receiving element.

[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-projecting 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 and thin 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 a sensor side end, and the tip end is a detection end. The light projection optical waveguide 410 is in a sheet shape wide in the horizontal direction, with the horizontal dimension (width dimension W) set longer than the vertical dimension (thickness dimension t) as shown in FIG. 8A. The main surfaces of the light projection optical waveguide 410 are the upper surface and the lower surface. 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 in which the horizontal direction shown in FIG. 6 faces the vertical direction, or in a position in which the horizontal direction is inclined 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 of cores 411 and clad 412, light incident on core 411 travels by undergoing total reflection at the boundary surface 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 a plurality of cores 411 is preferable because it is possible to increase the amount of light 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 part 412a that covers the cores 411 from above, a lower part 412b that covers the cores 411 from below, and an intermediate part 412c that is interposed between the cores 411 that are aligned in the horizontal direction. The upper part 412a of the clad 412, the cores 411, and the lower part 412b of the clad 412 are provided in layers in the vertical direction and integrated.

[0064] The middle portion 412c of the clad 412 extends from the upper portion 412a to reach the lower portion 412b. The upper portion 412a and the lower portion 412b are connected by the middle portion 412c. In the example shown in Fig. 8A, the cores 411 located at both ends of the light projection optical waveguide 410 in the width direction are not covered by the clad 412 and are exposed. However, the cores 411 located at both ends of the light projection optical waveguide 410 in the width direction may be covered by the clad 412.

[0065] As shown in FIG. 7, which is an enlarged plan view of the vicinity of the tip of the light projection optical waveguide 410, the tip of the intermediate portion 412c of the cladding 412 does not have to reach the tip of the light projection 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 projecting 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 light guide. Examples of materials for the light projection optical waveguide 410 include resins such as acrylic, epoxy, siloxane, silicone, polyimide, polysilane, polynorbornene, and fluororesin, but are not limited to these, and any material that satisfies desired optical characteristics and physical properties can be used as appropriate. Only one of the above materials may be used, or any combination of multiple materials may be used. In addition, additives for improving optical characteristics and physical properties may be added to the above materials. By forming the light projection optical waveguide 410 from the above-mentioned resin, the light projection optical waveguide 410 has flexibility and resilience, and also has a predetermined heat resistance.

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

[0069] 6, the light receiving optical waveguide 420 can be configured in the same manner as the light projecting optical waveguide 410, and has a core 421 and a clad 422. The light receiving optical waveguide 420 and the light projecting optical waveguide 410 may be exactly the same, 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 serving as reinforcing members on the outside of the light projecting optical waveguide 410, and are covered by an upper covering member 423 and a lower covering member 424 serving 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 having optical impermeability. 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. Thus, the light detection unit 400 is provided with covering members having a laminated structure.

[0071] That is, the lower surface of the clad 412 of the light projecting optical waveguide 410 is covered by a lower covering member 414, the lower surface of the clad 421 of the light receiving optical waveguide 420 is covered by a lower covering member 424, and these lower covering member 414 and lower covering member 424 are covered by a lower covering member 450. In addition, the upper surface of the clad 412 of the light projecting optical waveguide 410 is covered by an upper covering member 413, the upper surface of the clad 421 of the light receiving optical waveguide 420 is covered by an upper covering member 423, and these upper covering member 413 and upper covering member 423 are covered by an upper covering member 440. As shown in Fig. 4 and Fig. 5, the upper covering member 440 and the lower covering member 450 are formed in a sheet shape extending from the tip end of the light projecting optical waveguide 410 and the light receiving optical waveguide 420 to the base end side. 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 upper and lower 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 members that constitute a part of the optical waveguide 410, and in this case, the upper covering member 413 and the lower covering member 414 can be included in the term "optical waveguide 410." For example, when describing "making a hole in the optical waveguide 410," it also means making a hole in the upper covering member 413 and the lower covering member 414 on the upper and lower surfaces of the optical waveguide 410, but the description thereof will be omitted because it is complicated. Similarly, the upper covering member 423 and the lower covering member 424 can be members that constitute a part of the optical waveguide 420, and in this case, the upper covering member 423 and the lower covering member 424 can be included in the term "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-shielding 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-shielding property of, for example, 90% or more. The upper covering member 440 and the lower covering member 450 may have a light-shielding 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, in appearance. The resin material constituting the upper covering member 440 and the lower covering member 450 may be colored by printing.

[0074] The light projecting optical waveguide 410 and the light receiving optical waveguide 420 are made of a material 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 to reinforce the light projecting optical waveguide 410 and the light receiving optical waveguide 420 and to reflect light at the interface with them. One example of the material is polyimide. The upper covering member 440 and the lower covering member 450 provided on the outside thereof have light blocking properties as described above, and are colored or otherwise processed so as to have a higher light blocking property 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 a difference in light blocking property may be provided by printing black on upper covering member 440 and lower covering member 450. Note that air is contained 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. Air may be included when covering the laminate consisting of the light projecting optical waveguide 410, the upper covering member 413, and the lower covering member 414 and the laminate consisting of the light receiving optical waveguide 420, the upper covering member 423, and the lower covering member 424 with the upper covering member 440 and the lower covering member 450. This makes it possible to reduce light leakage due to the difference in refractive index between the light projecting optical waveguide 410 and the light receiving optical waveguide 420 and the 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 attached or bonded to the upper surface of the clad 412 of the light-projecting 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 integrally formed with the light-projecting 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 attached or bonded to the lower surface of the clad 412 of the light projecting 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 integrally formed with the light projecting 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 leakage of light 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, a resin sheet, or a resin film. Usable resin materials include, for example, polyimide, but are not limited to this, and any resin material may be used as long as it is flexible and has the strength to not break when fixed 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 one covering member without being separated into the upper covering member 440 and the lower covering member 450. The covering member may be bag-shaped, and the shape is 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 and the light receiving end which is the tip of the light receiving optical waveguide 420, and allow the light extraction member 430 to be optically coupled to 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 be marked with characters, symbols, marks, etc., indicating, for example, the name of the manufacturer, product number, model, 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 making the characters, symbols, marks, etc. a light color such as white, the characters, symbols, marks, etc., become more noticeable. By marking the characters, symbols, marks, etc., for example, only on the top surface, the user can easily determine which is the top surface. The upper covering member 440 or the lower covering member 450 may be marked with characters, symbols, marks, etc., as a direction indicator indicating the directions such as 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, since 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, so there is no adverse effect on detection performance.

[0082] Furthermore, in this embodiment, the light projecting optical waveguide 410 and the light receiving optical waveguide 420 are characterized by being sheet-like and thin, which allows the light detection unit 400 to be disposed in a thin 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 deteriorate the 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, improving the 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 provided by the upper covering member 440 and the lower covering member 450. In addition, 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 for the light detection unit 400 to 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 for the purpose of strengthening the end face. For example, in the case where the clad constituting light projection optical waveguide 410 is manufactured by modifying the core, core 411 has a strength greater than that of 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, so the part 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 provided 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, as shown in FIG. 9, the left and right of the light detection unit 400 are defined, but this is only for convenience of explanation and does not limit the actual usage state.

[0087] The light extraction member 430 can be made of a material having the same light guiding property as the material of the core 411 of the light projection optical waveguide 410. As shown in FIG. 10, the light extraction member 430 is made of a single core 430a. The light extraction member 430 may have a clad similar to the clad 412 of the light projection optical waveguide 410. The lower surface of the light extraction member 430 is adhered or bonded to the lower covering member 450, and the upper surface of the light extraction member 430 is adhered or bonded to the upper covering member 440. This can prevent the relative positions of the light extraction member 430, the light projection optical waveguide 410, and the light receiving optical waveguide 420 from being shifted, and can cover the light extraction member 430 with the upper covering member 440 and the lower covering member 450.

[0088] 9, the right side of the light extraction member 430 is abutted 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 the 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 is provided as a light-emitting portion on the right side of the upper surface of the light-extracting member 430. The light-emitting mirror surface 432 is formed of a surface inclined at a predetermined angle with respect to the upper surface of the light-extracting member 430, and the direction of light that is incident on the right side of the light-extracting member 430 and 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 of the light-projecting optical waveguide 410 becomes a light-projecting end, which projects light into the detection region R through the light-extracting member 430. The light-extracting mirror surface 432 can be obtained by, for example, laser processing. A vapor-deposited film in which a metal is vapor-deposited may be formed on the light-extracting mirror surface 432 in order to improve reflectance.

[0091] The light incidence and emission aperture angle NA can be set to about 0.2, which allows a small light projection spot and light receiving field of view to be realized without adding lenses or the like. The light paths shown in each figure may be reversed. That is, the light projection side in each figure may be the light receiving side, and the light receiving side may be the light projection side. The distance between the light detection unit 400 and the workpiece WK is not particularly limited, but may be, for example, about 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 emission angle of the light can be changed by changing the angle of the light emitting mirror surface 432.

[0093] Moreover, the left side of the light extraction member 430 is abutted 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 side 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 region R, the light irradiated to 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 portion 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 tip on the left side of the light extraction member 430. The left inclined surface 434 is a reflecting surface, and the traveling direction of light incident from the light incident mirror surface 433 into the light extraction member 430 and traveling to the left is converted by the left inclined surface 434 and 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 incident on the left side of the light extraction member 430 is converted in direction toward the base end side 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 through the light extraction member 430. The light exit 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 when optically coupling them, but it is easy to optically couple multiple cores to a core having 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 a mounting member 600 that is the object of installation. The mounting member 600 may be, for example, a member that constitutes 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 by a fastening member 601 made of an adhesive, a bonding material, a double-sided tape, or the like. At this time, the lower surface of the lower cover member 450 becomes the installation surface and becomes the surface that is fixed to the mounting member 600. When the installation surface is horizontal, the light projection optical waveguide 410 and the light reception optical waveguide 420 are aligned horizontally, but as shown in Fig. 3, the light projection hole 376 and the light reception hole 378 of the optical sensor 1 are aligned vertically, so that it is necessary to twist the light projection optical waveguide 410 and the light reception optical waveguide 420 midway. In this case as well, the light-leading optical waveguide 410 and the light-receiving optical waveguide 420 covered with the upper covering member 440 and the lower covering member 450 are sheet-shaped and have a certain degree of softness and flexibility, and therefore 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 screwed to the mounting member 600 using a fixing plate 602. The fixing plate 602 is made of, for example, hard resin or metal material, and is formed so as 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 side of the light detection unit 400. On both sides in the width direction of the fixing plate 602, insertion holes (not shown) through which the screws 603 are inserted are formed. These insertion holes are positioned outside the tip side of the light detection unit 400, and when the fixing plate 602 is placed on the upper surface of the tip side 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 side 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 arranged so as not to cover the light exit mirror surface 432 and the light entrance mirror surface 433. Instead of the screw 603, a nail, a stapler, or the like may be used.

[0100] FIG. 15 shows an example in which the light detection unit 400 is fixed to the mounting member 600 by the hook-shaped member 604. FIG. 15 shows a vertical cross section perpendicular to the longitudinal direction of the light detection unit 400. The hook-shaped member 604 is formed so as to surround the mounting member 600, and is made of, for example, hard resin or metal material. 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 in the thickness direction between the hook-shaped member 604 and the mounting member 600. The hook-shaped member 604 is arranged so as not to cover the light exit mirror surface 432 and the light entrance mirror surface 433.

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

[0102] The first through hole 402 is located closest to the base end, and the fourth through hole 405 is located closest to the tip end. The second through hole 403 and the third through hole 404 are located between the first through hole 402 and the fourth through hole 405, and the second through hole 403 is closer to the base end than the third through hole 404. The third through hole 404 is close to the fourth through hole 405. The first to fourth through holes 402 to 405 may be formed as elongated holes. The first to fourth through holes 402 to 405 are located in portions of the covering members 440 and 450 corresponding to the portions between the light projecting optical waveguide 410 and the light receiving optical waveguide 420, and are designed not to affect the light projecting optical waveguide 410 and the light receiving optical waveguide 420.

[0103] As shown in Fig. 16 and Fig. 17, when the screw 605 is inserted into the first to fourth through holes 402 to 405 and screwed into the mounting member 600, the peripheral parts of the first to fourth through holes 402 to 405 can be sandwiched and fixed between the head of the screw 605 and the mounting member 600. The number of the through holes and the number of the screws 605 are not limited to four, and may be, for example, one. The peripheral parts of the first to fourth through holes 402 to 405 become fixed parts 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 parts of the first to fourth through 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 fixed by being sandwiched between the head of screw 605 and mounting member 600.

[0105] 19, when covering member 450 is provided at a portion to be fixed to mounting member 600, mounting regions 602 in which light-projecting optical waveguide 410 and light-receiving optical waveguide 420 and / or covering member 450 are expanded may be provided on both sides of covering member 450 in the width direction, and holes provided 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 sides of the width direction.

[0106] 20 , when covering member 450 is provided at a portion to be fixed to mounting member 600, a mounting region 602 in which light-projecting 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 provided in mounting region 602 may be fastened with screws 605. In this case, the tip side of covering member 450 can be fixed by being sandwiched between the head of screw 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 projecting optical waveguide 410 and the light receiving optical waveguide 420 and / or the covering member 450 are expanded may be provided at a portion between the tip side of the covering member 450 and the light projecting optical waveguide 410 and the light receiving optical waveguide 420, and a hole provided in the mounting region 602 may be used for fixing. The tip side of the covering member 450 can be fixed by being sandwiched between the head of a screw 605 and the mounting member 600, and the portion of the covering member 450 between the light projecting optical waveguide 410 and the light receiving optical waveguide 420 can be fixed by passing the screw 605 through 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 perpendicular to the longitudinal direction of the light detection unit 400, and shows a 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 screwed into 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, so that a strong force is unlikely to act on the light detection unit 400 in the vertical direction, and damage to the light projection optical waveguide 410, the light reception optical waveguide 420, and the light extraction member 430 can be suppressed. The fixing portion is not limited to the fourth through-hole 405, but may be any of the first to third through-holes 402 to 404. A similar fixing method may be adopted for any two or more of these through-holes 402 to 405.

[0109] The above-mentioned fixing method is an example, and various methods can be adopted as long as they are a method for fixing the light detection unit 400 to the mounting member 600. For example, a fixing method using a cable tie, wire, or the like can be adopted. In addition, the light detection unit 400 can be fixed to the mounting member 600 by combining any two or more of the above-mentioned multiple fixing methods.

[0110] Also, the connector portion 500 may be omitted, and the base ends of the light-projecting optical waveguide 410 and the light-receiving optical waveguide 420 may be fixed to the optical sensor 1 so as not to be removable.

[0111] (Optical Waveguide Connection Structure) 23A is a vertical cross-sectional view of a connection portion of two light projecting optical waveguides 410A and 410B, and as shown in this figure, the two light projecting optical waveguides 410A and 410B can be connected for use. The end face of the light projecting optical waveguide 410A and the end face of the light projecting optical waveguide 410B may be directly butted against each other for connection, or a transparent elastic material 460 or a transparent adhesive material may be interposed between the end face of the light projecting optical waveguide 410A and the end face of the light projecting optical waveguide 410B so that no air layer remains between them.

[0112] A reinforcing material 461 may be provided continuously from the light projection optical waveguide 410A to the light projection optical waveguide 410B. The reinforcing material 461 is a tape-like member attached to the lower surface of the light projection optical waveguide 410A and the lower surface of the light projection optical waveguide 410B, and has flexibility. The reinforcing material 461 preferably has a property of not expanding or contracting in the longitudinal direction of the light projection optical waveguide 410A, and this can prevent a gap from being generated between the light projection optical waveguides 410A and 410B when the two light projection optical waveguides 410A and 410B are pulled in a direction away from each other, for example, and can suppress a decrease in efficiency. The reinforcing material 461 may be provided on the upper surfaces of the light projection optical waveguide 410A and the light projection optical waveguide 410B.

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

[0114] (Example of optical waveguide formation) Fig. 24 shows a configuration example in which limited reflection is realized by forming the light projecting optical waveguide 410 and the 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 in 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] Moreover, the tip side of the light receiving optical waveguide 420 is bent in a direction approaching the light projecting optical waveguide 410 at the tip side of the optical waveguide forming member 470. The optical waveguide forming member 470 is formed with a light incident mirror surface 433 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 through the light incident mirror surface 433. In this example, the light exit mirror surface 432 and the light incident mirror surface 433 can be provided on the optical waveguide forming member 470 provided with the light projecting optical waveguide 410 and the light receiving optical waveguide 420 without providing a separate light extraction member 430, so that the relative positional deviation between the members does not occur, and the deterioration of detection accuracy can be suppressed. It can also be said that the light extraction member is incorporated into the light projecting optical waveguide 410 and the light receiving optical waveguide 420 to form an integrated configuration.

[0117] 25 shows a configuration example in which a reflector 471 made of a separate member is provided at the tip of the light projecting optical waveguide 410 and the light receiving optical waveguide 420 to realize limited reflection. The reflector 471 is made of a resin material with high light reflectance, for example, white, and the tip of the light projecting optical waveguide 410 and the tip of the light receiving optical waveguide 420 are inserted and held in the reflector 471. The tip 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. The 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 side. Reflector 471 is provided with a light emitting mirror surface 432. When light traveling through light projection optical waveguide 410 is reflected by first inner surface 471a of reflector 471, it reaches light emitting mirror surface 432 and travels to detection region R via light emitting mirror surface 432.

[0118] Further, the tip 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 exit 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 incident on the light receiving optical waveguide 420. In this example, the tip portions of the light projection optical waveguide 410 and the light receiving optical waveguide 420 can be held by the reflector 471, and therefore, relative positional deviation between the members can be suppressed.

[0119] 26 is a plan view of the light detection unit 400 showing an example of a pattern of the light guide in consideration of reducing light loss. The vicinity of the tip side of the light projection light waveguide 410 extends so as to be curved while maintaining a large curvature, and the vicinity of the tip side of the light reception light waveguide 420 also extends so as to be curved while maintaining a large curvature. By increasing the curvature of the light projection light waveguide 410 and the light reception light waveguide 420, the width of the light detection unit 400 increases, but if the layout of the light detection unit 400 allows the width of the light detection unit 400 to be increased, the light loss can be reduced by using a pattern with a large curvature as in this example.

[0120] 27A, a light output mirror surface 432 can be provided at the tip of the light leading optical waveguide 410. Similarly, a light input 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 surface 410a of light projection optical waveguide 410 with direction setting member 472. The light incident side can also be set by a direction setting member (not shown) in the same manner.

[0122] FIG. 28 is a plan view of the light detection unit 400 showing an example of a pattern of the light waveguide with priority given to the outer size. The vicinity of the tip side of the light projection light waveguide 410 extends in a direction away from the light reception light waveguide 420, and the vicinity of the tip side of the light reception light waveguide 420 extends in a direction away from the light projection light waveguide 410. However, compared to the example shown in FIG. 26, the distance between the vicinity of the tip side of the light projection light waveguide 410 and the vicinity of the tip side of the light reception light waveguide 420 is set to be shorter. This allows the width of the light detection unit 400 to be narrowed, so that it can be used in a case where the installation location is narrow. A light output mirror surface 432 can be provided at the tip of the light projection light waveguide 410, and a light input mirror surface 433 can be provided at the tip of the light reception light 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 FIG. 29 of the upper covering member 440 and the lower covering member 450, which sandwich the light-leading 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 surface) on the tip side of the light projecting optical waveguide 410 serves as the light projecting surface, and the end face (side surface) 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 receiving surfaces.

[0126] As shown in FIGS. 24, 26, 28 and 30, in addition to straight line patterns, core patterns can be freely drawn within the optical waveguides 410 and 420, allowing high freedom in designing the optical paths within the optical waveguides 410 and 420.

[0127] Fig. 31 shows another example of limited reflection in which light is emitted from the tip of the optical waveguide. In this example, the light that has traveled through the core 411 of the light-projecting optical waveguide 410 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 made to enter from the tip of the light-receiving optical waveguide 420. The example shown in Fig. 31 has an optical path similar to that in Fig. 30, but it is also possible to change the optical path by using the refractive index difference between the optical waveguide and the outside by cutting the side of the optical waveguide obliquely instead of using a pattern within the optical waveguide.

[0128] 32, light can also be emitted and incident from the side of the optical waveguide. In this example, the light that has traveled through the core 411 of the light projecting optical waveguide 410 can be irradiated onto the workpiece WK from the side of the light projecting optical waveguide 410. Light from the detection region R can also be incident on the light receiving optical waveguide 420 from the side. 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 emission mirror surface 432 at the tip of the light projection optical waveguide 410, light can be irradiated onto the workpiece WK from the side of the light projection optical waveguide 410. By providing a light incidence 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 may remain linear.

[0130] 34 shows an example in which the light detection unit 400 is used as a multi-point reflection type light detection unit. The light 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 light detection unit 400, and light from multiple directions can be received at the tip of the light detection unit 400, so that even if there are irregularities on the surface of the workpiece WK, the effect of the irregularities can be reduced and detection accuracy can be improved.

[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 irradiated 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 within a plane according to a 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 so as to face the tip of the light projecting optical waveguide 410. A light exiting mirror surface 480a is formed on the light projecting mirror member 480, and this light exiting mirror surface 480a allows light to be emitted upward from the light projecting optical waveguide 410. A light receiving mirror member 481 is disposed so as to face the tip of the light receiving optical waveguide 420. A light receiving mirror member 481 is formed on the light receiving mirror member 481, and this light exiting mirror surface 481a allows light to be incident from above the light receiving optical waveguide 420.

[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 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. Moreover, the tip of light-receiving optical waveguide 420 and light-receiving mirror member 481 are arranged to abut against each other, and this configuration also allows light to be incident from above light-receiving optical waveguide 420.

[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, the 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 is blocked by the workpiece WK, and the light cannot be received by the light receiving optical waveguide 420. This example can be applied to a detection method that utilizes this fact.

[0135] (Transmissive light 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 transmission type optical detection unit 400 in which the light projecting optical waveguide 410 and the light receiving optical waveguide 420 extend in the same direction. The light that has traveled through the light projecting optical waveguide 410 is redirected toward the light receiving optical waveguide 420 by a light exit mirror surface 432 provided at the tip of the light projecting optical waveguide 410. The light that has traveled from the light projecting optical waveguide 410 is received by the light receiving optical waveguide 420, and its direction is changed by the light entrance mirror surface 433 before traveling 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 output mirror surface 432, and this 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 interval 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, the 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 portion 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 portion 459 and received at the tip of the light receiving optical waveguide 420. When the workpiece WK is inserted into the insertion portion 459, the light projected from the light projecting optical waveguide 410 is blocked.

[0140] 41 shows an example of a transmissive 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, the tip of the light receiving optical waveguide 420 can receive light from multiple optical paths. In this example, the detection range can be widened.

[0141] (Connector part 500) 4 shows a form having a connector section 500, and shows a state before the connector section 500 is connected to the light projecting optical waveguide 410 and the light receiving optical waveguide 420. The connector section 500 is a member to which the base end of the light projecting optical waveguide 410 and the base end of the light receiving optical waveguide 420 are connected. The connector section 500 is a member that 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 detachably attached to the light projecting hole 376 and the light receiving hole 378. The material constituting the connector section 500 can be, for example, a resin material, and the color of the resin material is preferably a color that does not transmit light or a color that transmits almost no light.

[0142] 42 to 46, a connector section 500 according to a first example of this embodiment has a main body section 501, and a light projecting side convex section 502 and a light receiving side convex section 503 protruding from the main body section 501, and the light projecting optical waveguide 410 and the light receiving optical waveguide 420 can be integrated by the connector section 500. The light projecting side convex section 502 and the light receiving side convex section 503 are portions that are inserted into the light projecting hole 376 and the light receiving hole 378 (shown in FIG. 3) of the optical sensor 1, respectively. Therefore, the interval between the light projecting side convex section 502 and the light receiving side convex section 503 is approximately the same as the interval between the light projecting hole 376 and the light receiving hole 378 of the optical sensor 1.

[0143] The cross section of the light-projecting side convex portion 502 is a substantially circular shape surrounding the periphery of the light-projecting optical waveguide 410, and substantially coincides with the cross section of the light-projecting hole 376 of the optical sensor 1. The outer diameter of the light-projecting side convex portion 502 is set to be larger than the thickness dimension of the light-projecting optical waveguide 410. The outer diameter of the light-projecting side convex portion 502 can be set to be slightly smaller than the light-projecting hole 376 of the optical sensor 1, but the gap formed between the light-projecting side convex portion 502 and the light-projecting side convex portion 502 when inserted into the light-projecting hole 376 is small. This allows the light-projecting side convex portion 502 to be positioned in the radial direction. The length of the light-projecting side convex portion 502 corresponds to the depth of the light-projecting hole 376, and the tip surface of the light-projecting 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-projecting side convex portion 502 is inserted into the light-projecting hole 376. The insertion depth of light-projecting side convex portion 502 can be determined by abutting the tip face of light-projecting side convex portion 502 against the end face of reflector 380. The insertion depth of light-projecting 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-projecting side convex portion 502, and is a substantially circular shape that surrounds the periphery of the light-receiving optical waveguide 420. With the light-receiving side convex portion 503 inserted into the light-receiving hole 378 of the optical sensor 1, positioning is performed 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 so as to cover the outer peripheral surface of the base end of the light guide 401. A plurality of engagement protrusions 504a are formed on the elastic material 504. The main body 501 is formed with an engagement hole 501b into which the engagement protrusions 504a of the elastic material 504 are engaged. When the engagement protrusions 504a of the elastic material 504 are engaged with the engagement hole 501b of the main body 501, the elastic material 504 is prevented from coming off the main body 501. The elastic material 504 may be omitted.

[0146] The light projection optical waveguide 410 of the light guiding section 401 passes through the light projection side convex section 502. As in the first example shown in FIG. 47, the tip of the light projection optical waveguide 410 reaches the tip face of the light projection side convex section 502 and is exposed at the tip face. The tip of the light projection optical waveguide 410 and the tip face of the light projection side convex section 502 may be flush with each other, or the tip of the light projection optical waveguide 410 may be recessed from the tip face of the light projection side convex section 502. When the tip of the light projection optical waveguide 410 is recessed, damage to the tip of the light projection optical waveguide 410 can be prevented. When the tip of the light projection optical waveguide 410 is recessed, the distance between the tip of the light projection optical waveguide 410 and the tip face of the light projection side convex section 502 is preferably set to 0.5 mm or less. This is to suppress a decrease in the amount of light.

[0147] As shown in FIG. 48, the light-projection side convex portion 502 is formed with a concave light-projection side accommodation portion 502a for accommodating the light projection optical waveguide 410. The light-projection side accommodation portion 502a opens on the outer peripheral surface of the light-projection side convex portion 502. The light-projection side accommodation portion 502a is provided with a pressing member 505 for pressing and holding the light projection optical waveguide 410. The pressing member 505 engages with the inner surface of the light-projection side accommodation portion 502a and is held at a predetermined position, thereby determining the relative position of the light projection optical waveguide 410 with respect to the light-projection side convex portion 502. Therefore, the light-projection side convex portion 502 positions the tip portion of the light projection optical waveguide 410 at the center position of the light emission surface of the light-emitting element 104 shown in FIG. 3 in a state where it is inserted into the light projection hole 376 of the optical sensor 1. 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] Further, the light receiving side convex portion 503 is formed with a concave light transmitting side housing portion 503a for housing 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 for pressing and holding the light receiving optical waveguide 420. The pressing member 506 is engaged with the inner surface of the light receiving side housing portion 503a and held at 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, the light receiving side convex portion 503 positions the tip portion of the light receiving optical waveguide 420 at the center position of the light receiving surface of the light receiving element 204 shown in FIG. 3 when inserted into the light receiving hole 378 of the optical sensor 1.

[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] The lower member 512 is formed with a first groove 512a that holds the light-projecting optical waveguide 410 protected by the protective elastic material 513, and a second groove 512b that holds the light-receiving optical waveguide 420 protected by the protective elastic material 514. The upper member 511 is formed with a first fitting portion 511a that fits into the first groove 512a, and a second fitting portion 511b that fits into the second groove 512b. By fitting the first fitting portion 511a into the first groove portion 512a, the light-projecting 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, a third fitting portion 511c that fits into light-emitter side accommodating portion 502a and a 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 third fitting portion 511c and fourth fitting portion 511d can hold down light-emitter optical waveguide 410 and light-receiving optical waveguide 420.

[0152] FIG. 50 shows a connector section 500 according to a third example of the present embodiment. In the connector section 500 of the third example, a main body section 520, a light-emitter side convex section 522, and a light-receiving side convex section 523 are configured as separate members. The light-emitter side convex section 522 and the light-receiving side convex section 523 are each configured as a rod-shaped member. The light-emitter side convex section 522 is configured as a base member 522a having a shape with a part cut out, and a fitting member 522b that fits into the cut out portion. By disposing the light-emitter optical waveguide 410 in the cut out portion of the base member 522a, it becomes possible to position the light-emitter optical waveguide 410 with respect to the base member 522a. With the light-emitter optical waveguide 410 positioned, the fitting member 522b is fitted into the cut out portion of the base member 522a, so that the light-emitter optical waveguide 410 can be held immovable. 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 about 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 adaptor 540 may be provided in advance on the optical sensor 1. In this example, the light detection unit 400 can be connected to the optical sensor 1 via the pre-installation adaptor 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. The slit-shaped insertion openings 376a, 378a approximately match the cross-sectional shapes of the light projecting optical waveguide 410 and the light receiving optical waveguide 420, so that 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 projecting side connector portion 550 and light receiving side connector portion 551 according to a fourth example of the embodiment. Light projecting side connector portion 550 is formed in a cylindrical shape that can be inserted into light projecting hole 376 of optical sensor 1 for positioning. Light projecting side connector portion 550 is formed with a slit-like hole portion 550a into which light projecting optical waveguide 410 is inserted. Light receiving side connector portion 551 is similarly configured, is formed in a cylindrical shape that can be inserted into light receiving hole 378 of optical sensor 1 for positioning, and has a slit-like hole portion 551a.

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

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

[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 projecting side optical fiber 560 and the light receiving side optical fiber 561 are held by fiber adapters 560b and 561b in a state in which the optical fiber lines 560a and 561a are aligned in the horizontal direction (width direction of the optical waveguides 410 and 420), respectively. The fiber adapters 560b and 561b are fixed in a state in which they are accommodated in the connector case 581. In the connector case 581, the light projecting 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 the light projecting side optical fiber 560 coincides with the width direction of the light projecting optical waveguide 410, and the optical fiber lines 560a are arranged from a portion corresponding to one end in the width direction of the light projecting optical waveguide 410 to a portion corresponding to the other end. Similarly, on the light receiving side, the arrangement direction of optical fiber lines 561a coincides with the width direction of the light receiving optical waveguide 420, and the optical fiber lines 561a are arranged from a portion corresponding to one end in the width direction of the light receiving optical waveguide 420 to a portion corresponding to the other end.

[0162] A light projecting rod lens 582 that is long in the width direction of the light projecting optical waveguide 410 is provided between the tip of the light projecting optical fiber 560 and the base end of the light projecting optical waveguide 410. A light receiving rod lens 583 that is long in the width direction of the light receiving optical waveguide 420 is provided between the tip of the light receiving optical fiber 561 and the base end of the light receiving optical waveguide 420. A transparent elastic material or adhesive material may be provided instead of the light projecting rod lens 582 and the light receiving rod lens 583. Alternatively, the light projecting rod lens 582 and the light receiving rod lens 583 may be omitted and the tip of the light projecting side optical fiber 560 may be butted against the base end of the light projecting optical waveguide 410, or the tip of the light receiving side optical fiber 561 may be butted against the base end of the light receiving optical waveguide 420. A single core may be used without using a plurality of optical fiber wires.

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

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

[0165] In Fig. 55A, the indicator light 585 is provided on the light receiving side, but it may be provided on the light projecting side. The light source of the indicator light may be the LED 212 shown in Fig. 3, or may be light emitted from the light emitting element 104 used for detection or light reflected by the workpiece WK. The indicator light may be realized by cutting a part of the surface of the optical waveguide, but the loss of detection light can be reduced by making good use of the leak light generated at the coupling end surface between the optical waveguides 410, 420 and the 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 in relay connector 580, the through hole on the tip side communicates with a through hole provided between optical waveguides or in the optical waveguide.

[0167] Further, a reinforcing plate 461 is provided at the tip of the optical waveguides 410 and 420. The reinforcing plate 461 is preferably made of metal or resin and is thin and strong. By attaching the reinforcing plate 461 onto 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 back 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 back surfaces of the optical waveguides 410 and 420. In addition, the surface on which the reinforcing plate 461 is provided is not limited to the main surfaces of the optical waveguides 410 and 420, and the end faces on three sides of the detection unit may also be surrounded by the reinforcing plate 461. In addition, 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 communicating 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 screw fastening.

[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 relay connector case 581 or the tape of 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 explanation will be given of an assembly method for optically coupling optical waveguides 410, 420 and optical fibers 560, 561 in relay connector 581. By adopting the configuration as 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 butted efficiently. (Description of the configuration of the relay connector part in Figure 56B) 1. The tip coating of the optical fibers 560 and 561 (bundle fiber) is stripped, and the bundle fiber is aligned in a line in the fiber adapters 560b and 561b. 2. The optical waveguides 410, 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, 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 shape). 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 shape). 5. The fiber adapters 560b, 561b and the optical waveguides 410, 420 fitted into the connector case 581 are moved in the longitudinal direction, and the optical coupling end faces are butted together or a small gap is left, and the fiber adapters 560b, 561b and the bases of the optical waveguides 410, 420 are fixed with a hard adhesive, and the optical coupling portion is fixed 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 be configured with three components. 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 disposed between first holding member 591 and second holding member 592.

[0174] 58, first holding member 591 has holding holes 591a, 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, 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] Moreover, the optical fibers 560 and 561 extending from the relay connector 580 may be free-cut optical fibers. For the free-cut optical fibers, the length of the optical fibers can be adjusted by using a free-cut jig.

[0177] In addition, in the first to third examples of the relay portion, when a thin-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 degree of freedom in terms 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 a degree of design freedom that allows for free design in consideration of the coupling efficiency with the optical waveguide.

[0179] In this embodiment, as shown in FIG. 6 and FIG. 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 the optical sensor 1 is installed upright with the display unit 334 located on the upper surface, the light projection hole 376 and the light reception hole 378 are arranged vertically in the housing 10, and the light projection path and the light reception path of the optical waveguide are arranged horizontally in the sheet-like direction. Therefore, two vertically aligned paths are arranged horizontally, and a twisting section is required between the optical sensor 1 and the tip of the optical waveguide to align the vertically aligned paths horizontally. It is easier to twist a thin linear optical fiber than to twist a sheet-like optical waveguide, and this can reduce breakage, light leakage, and loss.

[0181] (Effects of the embodiment) According to this embodiment, the optical waveguides 410, 420 are in the form of a sheet 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 that 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 the covering members 440, 450 serve as installation surfaces for an attachment target, so that the thin optical waveguides 410, 420 can be easily installed on an attachment target.

[0182] Moreover, the optical waveguides 410, 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, so that it is 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 embodiment is merely illustrative 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, for example, the presence or absence of an article. [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 Light detection unit 402~405 1st~4th insertion hole (fixed part) 410 Light guide for projection 411 Core 412 Clad 420 Optical waveguide for light reception 421 Core 422 Clad 440 Upper covering member 430 Light extraction components 432 Light exit mirror surface (light exit part) 433 Light entrance mirror surface (light entrance 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 Line 582 Light-emitting rod lens 583 Receiving rod lens 585 Indicator light 588 Through hole in intermediate connector

Claims

1. a light emitting element that projects detection light toward a detection area; a light receiving element that receives the detection light from the detection region; a light projection hole for optically coupling to the light emitting element; a light receiving hole for optically coupling to the light receiving element; a signal generating unit that generates a detection signal indicating a comparison result by comparing a light receiving signal generated by the light receiving element with a threshold value, the light detection unit being insertably and removably connected to the light projecting hole or the light receiving hole of an optical sensor, an optical waveguide having a wide sheet shape with a width dimension set longer than a thickness dimension and guiding light between a first end and a second end, a core and a clad surrounding the core, the core and the clad being arranged in layers in the thickness direction, the first end being connected to the light projecting hole or the light receiving hole 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 projecting end or a light receiving end for projecting light to the detection region or receiving the light from the detection region; a connector portion to which the first end of the optical waveguide is connected, optically connecting the first end of the optical waveguide directly or indirectly to the light projecting hole or the light receiving hole of the optical sensor, and being detachably attached to the light projecting hole or the light receiving hole; having The optical detection unit has an optical waveguide provided with a hole for fixing the optical waveguide.

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 projecting hole or the light receiving hole.

3. 3. The optical detection unit according to claim 2, the first end of the optical waveguide is exposed at a tip surface of the protrusion, The convex portion is a light detection unit that positions 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 projecting hole or the light receiving hole.

4. 2. The optical detection unit according to claim 1, the optical waveguide includes a light-projecting optical waveguide connected to the light-projecting hole of the optical sensor, the second end serving as a light-projecting end for projecting the light to the detection area, and a light-receiving optical waveguide connected to the light-receiving hole of the optical sensor, the second end serving as a light-receiving end for receiving the light from the detection area; The connector portion is an optical detection unit that integrally bundles together a light-projecting side optical fiber that is connected to the first 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 first 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 including 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 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, 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 is provided between the light projection side optical fiber and the light projection optical waveguide;

8. a light projection hole optically coupled to a light emitting element within the housing; a light-receiving hole that is optically coupled to a light-receiving element in the housing; and a light detection unit that is removably connected to an optical sensor having the light-receiving hole, a sheet-like first optical waveguide having a sensor side end optically coupled to the light projecting hole and a detection end disposed so as to project detection light toward a detection area, the first optical waveguide having a core through which the detection light passes and a cladding surrounding the core; a sheet-like second optical waveguide having a sensor side end optically coupled to the light receiving hole and a detection end disposed to receive the detection light from the detection region, the second optical waveguide having a core through which the detection light passes and a cladding surrounding the core; a connector portion that integrates the first optical waveguide and the second optical waveguide; a light projection provided in the connector portion, the light projection having a circular cross section surrounding the periphery of the sensor side end of the first optical waveguide and having the same size as the light projection hole; a light receiving side protrusion provided on the connector portion, the light receiving side protrusion having a circular cross section surrounding the periphery of the sensor side end of the second optical waveguide and having the same size as the light receiving hole; having The optical detection unit, wherein the first optical waveguide and the second optical waveguide are provided with holes for fixing the first optical waveguide and the second optical waveguide.

9. 9. The optical detection unit according to claim 8, The outer diameter of the light-emitter convex portion is set to be larger than the thickness dimension of the first optical waveguide.

10. 9. The optical detection unit according to claim 8, The light-emitting convex portion and the light-receiving convex portion are optical fibers.

11. 11. The optical detection unit according to claim 8, the light projecting hole and the light receiving hole of the optical sensor are arranged side by side in a vertical direction with respect to the housing, the light projecting path and the light receiving path of the first optical waveguide and the second optical waveguide are aligned in a lateral direction of a sheet, a light detection unit having a twisted portion between a detection region of the first optical waveguide and a connection hole and a detection region of the second optical waveguide;

12. The optical detection unit according to claim 11, The twisted portion is an optical fiber portion of the light detection unit.

13. 8. The optical detection unit according to claim 1, An optical detection unit in which an indicator light for extracting light passing through a core of the optical waveguide to the outside is provided on the optical waveguide on the light-emitting side or the light-receiving side between the first end and the second end of the optical waveguide.

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

15. 13. The optical detection unit according to claim 8, The connector portion is a light detection unit that holds the first optical waveguide and the second optical waveguide.

16. 16. The optical detection unit according to claim 1, The light detection unit has a through hole in the connector portion for fixing the connector portion.

17. 8. The optical detection unit according to claim 4, The portion where the light projecting side optical fiber and the light receiving side optical fiber are optically coupled to the light projecting optical waveguide and the light receiving optical waveguide is a light detection unit located within the connector portion.

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