JP2014224702A - Light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source unit which allows optical information carried on an inspection object to be accurately read by reading reflected light or fluorescence from the inspection object in a wide angular range.SOLUTION: The light source unit includes: a light guide which comprises a light-transmissive tabular body having a plurality of side surfaces and has a light receiving surface formed in one side surface of the light-transmissive tabular body and extended in one direction and a light output surface formed in another side surface of the light-transmissive tabular body; and a plurality of light-emitting elements disposed to be arranged in the same direction as the one direction in which the light receiving surface of the light guide is extended. The light receiving surface of the light guide comprises a plane inclined relative to a reference surface extending in the one direction perpendicular to a front surface of the light-transmissive tabular body.

Description

  The present invention relates to a light source unit, and more particularly, to a light source unit that can be suitably used for a light detection device for inspecting and identifying an object by irradiating light.

  Conventionally, in order to inspect the surface of an inspection object such as a liquid crystal substrate, light is irradiated and light is applied to a thin inspection object such as paper by irradiating light with reflected light. 2. Description of the Related Art Photodetection devices that read optical information held on the surface of an inspection object are known. In such a light detection device, a light source unit having a light emitting element and a light receiving element is mounted, and the object to be inspected is irradiated on the object to be inspected with light having a specific wavelength from the light emitting element in the light source unit. Move relative to it. Next, the reflected light or fluorescence from the inspection object is received by the light receiving element in the light source unit, whereby the optical information carried on the inspection object is read. Then, based on the read optical information, a flaw of the inspection object is detected, or the authenticity of the inspection object is determined.

FIG. 8 is an explanatory diagram showing a configuration of an example of a photodetecting device on which a conventional light source unit is mounted, and FIG. 9 is an explanatory diagram showing a configuration of the light source unit in the photodetecting device shown in FIG. Such a photodetection device is disclosed in Patent Document 1, for example.
In this light detection device, a housing 70 having an insertion port 71 into which an inspection object W made of paper sheets is inserted and a discharge port 72 through which the inspection object W is discharged is provided. In the housing 70, a transport mechanism 75 that transports the inspection object W inserted into the insertion port 71 along the horizontal transport path 76 and discharges it from the discharge port 72 is provided. Further, a sensor 73 that detects whether or not the inspection object W is inserted into the insertion port 71 is provided in the vicinity of the insertion port 71 in the housing 70.

An intermediate position of the conveyance path 76 in the housing 70 is carried by the inspection object W by irradiating light to the inspection object W conveyed along the conveyance path 76 by the conveyance mechanism 75. A light source unit 80 for reading optical information is provided.
In the light source unit 80, two light emitting elements 81 and 82 are disposed above the transport path 76, and a light guide 85 extending in a direction intersecting the transport path 76 is disposed below the transport path 76. ing. The upper surface of the light guide 85 is a light receiving surface 86 that receives light from the inspection object W. Condensing portions 86a and 86b made of convex lenses protruding upward are integrally formed at positions facing the light emitting elements 81 and 82 on the light receiving surface 86. On the lower surface of the light guide 85, an inclined surface that is inclined with respect to the light receiving surface 86 is formed at a position facing each of the light converging portions 86a and 86b. By providing a reflective film on the inclined surface, light reflecting surfaces 87 and 88 for reflecting the light received by the light receiving surface 86 in the direction in which the light guide 85 extends are formed. One end surface of the light guide 85 is a light exit surface 89 that emits light from the light reflecting surfaces 87 and 88, and the light receiving element 90 is disposed to face the light exit surface 89.

  In the above-described light detection device, the light from the light emitting elements 81 and 82 is irradiated to the inspection object W transported into the housing 70 by the transport mechanism 75. And the light which permeate | transmitted the to-be-inspected object W is light-received by the light-receiving surface 86 of the light guide 85 via condensing part 86a, 86b. The light received by the light receiving surface 86 of the light guide 85 is reflected by the light reflecting surface 87 and then emitted from the light exiting surface 89. Light emitted from the light exit surface 89 of the light guide 85 is received by the light receiving element 90.

JP 2001-283281 A

However, the above-described photodetector has the following problems.
In the light source unit 80 described above, light is emitted from the light emitting elements 81 and 82 disposed so as to face the light receiving surface 86 of the light guide 85 with the inspection object W interposed therebetween in a direction perpendicular to the light receiving surface 86. Light that irradiates the inspection object W and passes through the inspection object W is incident on the light receiving surface 86.
By the way, in the method of detecting transmitted light in this way, it is not possible to suitably inspect an opaque inspected object that does not have good light transmittance. For such an object to be inspected, a light emitting element, a light guide and a light receiving element are all disposed above the transport path 76, and the object is irradiated with light to detect its reflected light or fluorescence. It is necessary.
In this case, since the reflected light and fluorescence from the object to be inspected are generated at various angles, the light receiving element cannot perform desired light reception. The reason is that the light receiving sensitivity of a light receiving element having a light receiving surface with a certain area generally has different incident angle dependencies between the central portion and the peripheral portion.
In other words, in the method of detecting transmitted light, the light emitting element is arranged directly above or directly below the light receiving surface of the light guide, so that the light is incident on the light receiving surface vertically, so the angle range is It didn't matter.
However, in the method of detecting reflected light or fluorescence, light near the center of the object to be inspected perpendicularly to the light receiving surface and the light receiving element is easy to detect, but light incident from the periphery is detected. It was difficult to do. As a result, the detectable range is narrowed even when the inspection object is irradiated with light, and it becomes difficult to accurately read the optical information carried on the inspection object.

  The present invention has been made based on the above circumstances, and its purpose is to read the reflected light or fluorescence of the inspection object in a wider angle range, and thereby optical information carried on the inspection object. It is to provide a light source unit that can accurately read the light.

The light source unit of the present invention comprises a translucent plate having a plurality of side surfaces, a light receiving surface extending in one direction formed on one side surface of the translucent plate, and the translucent plate A light source unit comprising a light guide having a light exit surface formed on another side surface of the body, and a plurality of light emitting elements arranged in the same direction as one direction in which the light receiving surface of the light guide extends. There,
The light receiving surface of the light guide is configured by a plane inclined with respect to a reference surface extending in the one direction perpendicular to the surface of the translucent plate-like body.

In the light source unit of the present invention, the light exit surface of the light guide extends in the one direction, and the light exit surface is configured by a plane inclined with respect to the reference surface, and constitutes the light exit surface. It is preferable that the inclination direction of the plane and the inclination direction of the plane constituting the light receiving surface are symmetric with respect to the reference plane.
Moreover, it is preferable that the said light guide is a thing whose inclination angle of the plane which comprises the said light-receiving surface with respect to the said reference plane is 0.5-4.5 degrees.

According to the light source unit of the present invention, the light receiving surface of the light guide is constituted by a plane inclined with respect to a reference plane perpendicular to the surface of the light-transmitting plate-like body constituting the light guide. When light is irradiated onto the object to be inspected by the light emitting element, the light incident on the light guide from the peripheral part of the light irradiation region is refracted at the light receiving surface, and then repeatedly reflected inside the light guide to provide a light exit surface. It is possible to approach the desired angle range before reaching the light receiving element via the above.
As a result, reflected light or fluorescence emitted from the light irradiation area irradiated with light from the light emitting element is likely to be adapted to the detectable angular range of the light receiving element. Can be detected.
Therefore, according to the light source device of the present invention, when used in a light detection device, the reflected light or fluorescence of the inspection object is read in a wider angle range, thereby optically carried on the inspection object. Information can be read accurately.

It is sectional drawing for description which shows the structure in an example of the photon detection apparatus by which the light source unit of this invention is mounted. It is explanatory drawing which expands and shows the structure inside the housing | casing in the light source unit of this invention. It is a top view of the light guide in the light source unit shown in FIG. (A) is the side view which looked at the light guide shown in FIG. 3 from the light-receiving part side, (b) is the side view which looked at the light guide shown in FIG. 3 from the light-emitting part side. It is explanatory drawing which shows the structure of the microprism group which comprises a 1st light reflection surface. It is explanatory drawing which shows the modification of the light guide used for the light source unit of this invention. It is a light beam distribution curve diagram by the light source unit according to Example 2 and Comparative Example 1. It is explanatory drawing which shows the structure in an example of the photon detection apparatus carrying the conventional light source unit. It is explanatory drawing which shows the structure of the light source unit in the photon detection apparatus shown in FIG.

Hereinafter, embodiments of the optical unit of the present invention will be described.
FIG. 1 is an explanatory cross-sectional view showing the configuration of an example of a photodetecting device in which the light source unit of the present invention is mounted. This light detection device irradiates light to the inspection object W, reads the optical information held on the surface of the inspection object W, and illuminates the inspection object W with the light source unit 10. Have Below the light source unit 10, a transport mechanism 40 for transporting the inspection object W in the horizontal direction is provided.

  The light source unit 10 includes a rectangular box-shaped casing 11 having an opening formed on the lower surface. A light transmitting window 12 is provided in the opening of the housing 11. In the housing 11, a light guide 20 made of a light-transmitting plate having a plurality of side surfaces is provided.

  3 is a plan view of the light guide in the light source unit shown in FIG. 1, FIG. 4 (a) is an explanatory diagram showing an enlarged side view of the light guide shown in FIG. (B) is explanatory drawing which expands and shows the side surface which looked at the light guide shown in FIG. 3 from the light emission part side. The light guide 20 is entirely formed of a translucent plate-like body, a light receiving surface 22 extending in one direction is formed on one side surface of the translucent plate-like body, and the translucent plate-like body. A light exit surface 27 is formed on the other side of the body. Specifically, the light guide 20 shown in FIG. 3 includes a substantially trapezoidal plate-shaped light receiving portion 21 and a substantially L-shaped plate-shaped light output portion 26. The light receiving unit 21 has a planar light receiving surface 22 extending in one direction on one side surface (lower surface in FIG. 3). At one end (right end in FIG. 3) in which the light receiving surface 22 of the light receiving portion 21 extends, a light outgoing portion 26 that is bent and extends in another direction different from the one direction is formed. In the example shown in FIG. 3, the light exiting portion 26 is connected to one end of the light receiving portion 21, a connecting portion 26 a extending in the same direction as the light receiving surface 22, and a first light to be described later and perpendicular to the light receiving surface 22. The main body portion 26b extends in the direction toward the reflecting surface 23 (upward in FIG. 3). The light exiting portion 26 has a light exiting surface 27 extending in the same direction (one direction) as the light receiving surface 22 on the end surface (upper surface in the drawing) of the main body portion 26b.

The light-receiving surface 22 in the light-receiving unit 21 is perpendicular to the surface 20a of the light-transmitting plate-like body constituting the light guide 20 and in the same direction as the light-receiving surface 22 (see FIG. 4A). It is constituted by one plane inclined with respect to the reference plane S extending in one direction.
The inclination angle θ of the plane constituting the light receiving surface 22 with respect to the reference surface S is preferably 0.5 to 4.5 °. When the tilt angle θ is less than 0.5 °, the angle and area range of light that can be detected by the light receiving element 30 described later is narrowed. On the other hand, when the inclination angle θ exceeds 4.5 °, the detection range of light that can be detected by the light receiving element 30 increases as the inclination angle increases, but the amount of light that can be detected tends to decrease. This range is appropriately determined and adopted.

  The light receiving unit 21 has a first light reflecting surface 23 that reflects light received by the light receiving surface 22 toward the light output unit 26 on a surface (upper surface in FIG. 3) facing the light receiving surface 22. The first light reflecting surface 23 is formed such that the distance from the light receiving surface 22 increases toward the light exiting portion 26.

As shown in FIG. 5, the first light reflecting surface 23 in this example is a microscopic structure in which a large number of microprisms 24 a extending in a direction perpendicular to one direction in which the light receiving surface 22 extends are arranged toward the light output portion 26. A prism group 24 is used. More specifically, the microprism group 24 is formed on the light receiving surface 22 and the parallel portions 24b having edges parallel to the light receiving surface 22 on the surface 20a of the light transmitting plate-like body constituting the light guide 20. The inclined portions 24c having edges that are inclined with respect to the light emitting portion 26 are formed in a staircase shape, and the distance from the light receiving surface 22 increases toward the light emitting portion 26. The parallel portion 24b and the one inclined portion 24c adjacent to the parallel portion 24b constitute one minute prism 24a.
In the illustrated example, the first light reflecting surface 23 is formed in a state of being inclined with respect to a direction perpendicular to the surface 20 a of the translucent plate-like body constituting the light guide 20. Specifically, the first light reflecting surface 23 is formed in a state inclined with respect to the reference surface S in a cross section perpendicular to one direction in which the light receiving surface 22 of the light receiving unit 21 extends. The inclination direction of the first light reflecting surface 23 is symmetric with respect to the reference surface S with respect to the inclination direction of the light receiving surface 22.

The angle formed between the parallel portion 24b and the inclined portion 24c in the micro prism 24a is, for example, 45 °.
Moreover, the level | step difference H between each parallel part 24b in the adjacent micro prism 24a is 0.05-0.5 mm, for example.
Further, the pitch P of the minute prisms 24a is, for example, 0.1 to 3.0 mm.

The light exit surface 27 in the light exit section 26 is constituted by a single plane inclined with respect to the reference plane S as shown in an enlarged view in FIG. The inclination direction of the plane constituting the light exit surface 27 is symmetric with respect to the inclination direction of the plane constituting the light receiving surface 22 with respect to the reference plane S.
By forming such a light exit surface 27, the same effect as that of the light receiving surface 22 described later is produced also on the light exit surface 27, and reflected light and fluorescence of the inspection object can be read from a wider area and angle range.

  The light exit portion 26 has a second light reflection surface 28 that reflects the light reflected by the first light reflection surface 23 toward the light exit surface 27 at a location facing the light exit surface 27. The second light reflecting surface 28 is formed such that the distance from the light emitting surface 27 increases as it goes to the light receiving unit 21. A light reflection film made of a metal film such as silver or aluminum, a dielectric multilayer film, or the like may be formed on the outer surface of the second light reflection surface 28. Further, the second light reflecting surface 28 in the illustrated example is formed in a state of being inclined with respect to a direction perpendicular to the surface 20 a of the translucent plate-like body constituting the light guide 20.

  The material constituting the light guide 20 is not particularly limited as long as it can transmit light to be guided. For example, a light-transmitting resin such as an acrylic resin, a glass material, or the like can be used. In addition, the light guide 20 is formed by joining the light receiving unit 21 and the light output unit 26 separately, even if the light receiving unit 21 and the light output unit 26 are continuously formed integrally. May be.

  An example of specific dimensions of the light guide 20 is as follows. The thickness of the translucent plate-like body constituting the light guide 20 is 4 mm, the length of the light receiving surface 22 of the light receiving unit 21 is 150 mm, The dimension of the boundary surface (shown by a broken line) with the light exit portion 26 is 22 mm × 4 mm, the length L1 of the connecting portion 26a in the light exit portion 26 is 50 mm, and the protruding length L2 of the main body portion 26b from the connecting portion 26a in the light exit portion 26 Is 40 mm, and the length of the light exit surface 27 in the light exit section 26 is 22 mm.

  The light guide 20 extends along a direction in which the light receiving surface 22 is perpendicular to the conveyance direction of the inspection object W (the direction perpendicular to the paper surface in FIG. 2), and the reference surface S is the inspection object. It arrange | positions so that it may become parallel to the light irradiation surface of W. The separation distance from the light receiving surface 22 of the light guide 20 to the inspection object W is, for example, 15 to 20 mm.

In the housing 11, a plurality of (for example, 15) light emitting elements 15 that irradiate light to the object W to be inspected are adjacent to the light guide 20 and the light receiving surface 22 of the light guide 20 extends. They are arranged in a line along one direction.
As the light emitting element 15, an LED element can be used, and one that emits visible light, one that emits ultraviolet light, or one that emits infrared light can be selected according to the purpose and application.
The form of the light emitting element 15 is not particularly limited, and may be a surface mount type or package type LED element, an LED chip, a lens integrated LED element, a bullet type LED element, or the like. The light-emitting element 15 in this example is a surface-mounted rectangular LED element, and the plane dimension thereof is, for example, 7 mm × 7 mm.
The arrangement pitch of the light emitting elements 15 is, for example, 10 mm.

  A spherical lens 16 is provided corresponding to each light emitting element 15 at a position facing each light emitting surface of the light emitting element 15. Each of the spherical lenses 16 is arranged such that one surface is a flat surface and the other surface is a convex surface, the surface on the light emitting element 15 side is a flat surface, and the light irradiation surface side surface of the inspection object W is a convex surface. Yes. The diameter of the spherical lens 16 is 5 mm, for example. Further, the distance between the light emitting element 15 and the spherical lens 16 is preferably 0.3 mm or less, more preferably 0.1 mm or less.

  In the housing 11, a light receiving element 30 that detects light emitted from the light exit surface 27 of the light guide 20 is opposed to the light exit surface 27. The light receiving element 30 is not particularly limited as long as it has sensitivity in the wavelength range of light from the object W to be inspected, and various elements can be used.

  In the example shown in the drawing, two reflecting mirrors 35 are located at a position between the light emitting element 15 and the light irradiation surface of the inspection object W with respect to the normal line of the reference surface S of the light guide 20. The light receiving surfaces 22 are arranged so as to face each other in an inclined state. The inclination angle of the reflecting mirror 35 with respect to the normal line of the reference surface S is, for example, 13 to 20 °.

  The transport mechanism 40 includes a transport belt 41 that holds the inspection object W and a transport roller 42 that moves the transport belt 41 in the horizontal direction.

  In the above-described photodetector, the inspection object W is transported by the transport mechanism 40 and passes below the light source unit 10. In the light source unit 10, the light from the light emitting element 15 is irradiated on the surface of the inspection object W through the spherical lens 16 and the light transmission window 12. Thus, a long rectangular light irradiation region S extending in one direction in which the light emitting elements 15 are arranged is formed on the surface of the inspection object W. Then, reflected light or fluorescence from the light irradiation region of the inspection object W is received by the light receiving surface 22 of the light guide 20 through the light transmission window 12. The light received by the light receiving surface 22 of the light guide 20 is reflected by the first light reflecting surface 23 toward the light output portion 26, thereby extending along the one direction in which the light receiving surface 22 extends in the light receiving portion 21. Is guided. The guided light enters the light exit portion 26 and is reflected by the second light reflecting surface 28 in the light exit portion 26, thereby being guided toward the light exit surface 27, and the light exit surface. 27 is emitted. The light emitted from the light exit surface 27 is incident on the light receiving element 30.

According to such a light source unit 10, the light receiving surface 22 of the light guide 20 is formed by a plane inclined with respect to the reference plane S perpendicular to the surface 20 a of the translucent plate-like body constituting the light guide 20. It is configured. Therefore, light incident on the light guide 20 from the periphery of the light irradiation region of the inspection object W is refracted on the light receiving surface 22, and then repeatedly reflected inside the light guide 20, passes through the light exit surface 27, and receives the light receiving element 30. Until reaching the desired angle range.
As a result, among the reflected light or fluorescence emitted from the light irradiation region irradiated with light by the light emitting element 15, the light emitted from the peripheral part is easily adapted to the detectable angular range of the light receiving element. It can be detected properly.
Therefore, according to the light source unit 10 of the present invention, the light receiving element 30 can detect the reflected light or fluorescence of the inspection object in a wider angle range, and can accurately detect the optical information carried on the inspection object W. Can be read.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications as described below can be added.
(1) It is not essential that the light exit surface 27 of the light guide 20 is configured by a plane inclined with respect to the reference plane S.
(2) If the light receiving surface 22 in the light guide 20 is configured by a plane inclined with respect to the reference plane S, the inclination direction is not limited to that shown in FIG. For example, as shown in FIG. 6A, the inclination directions of the light receiving surface 22 and the light exit surface 27 may be symmetrical to the light guide 20 shown in FIG.
(3) The light receiving surface 22 of the light guide 20 is configured by two flat surfaces 22a and 22b inclined in different directions, for example, symmetrical directions with respect to the reference surface S, as shown in FIG. 6B, for example. May be. Further, the light exit surface 27 may be constituted by two flat surfaces 27a and 27b inclined in different directions with respect to the reference surface S, for example, symmetrical directions.
(4) The translucent plate-like body constituting the light guide 20 has a light receiving surface 22 formed in one side and extending in one direction, and a light exit surface 27 formed on the other side. For example, the shape is not limited to that shown in FIG. For example, as shown in FIG. 6C, the light guide 20 is formed of a rectangular translucent plate-like body, and is opposed to the light receiving surface 22 formed in one side and extending in one direction, and the one side. And a light exit surface 27 formed on another side surface.
(5) The light source unit 10 of the present invention includes a light detection device that irradiates light to a translucent substrate for a liquid crystal display, for example, and detects foreign matter or scratches existing on the surface of the translucent substrate. The present invention can be used for a light detection device that irradiates light on an inspection object and reads optical information held on the surface of the inspection object. In such a light detection device, when light is irradiated on the translucent substrate from a direction inclined with respect to the surface thereof, when there are foreign matters or scratches on the surface of the translucent substrate, Light is diffused, and a part of the diffused light is received by the light receiving element 30 via the light guide 20.

  Specific examples of the light source unit of the present invention will be described below, but the present invention is not limited to these examples.

<Examples 1-6>
A light source unit having the following specifications was produced according to the configuration shown in FIGS.
(1) Light guide body Material of translucent plate: acrylic resin Thickness of translucent plate: 4 mm
Light receiving surface: a surface formed by a single plane inclined with respect to the reference surface.
Inclination angle θ of the plane constituting the light receiving surface with respect to the reference surface: As shown in Table 1 below (however, when tilted in the clockwise direction when viewed from the light receiving unit side, when tilted in the counterclockwise direction) Indicated as-).
Length of light receiving surface: 150mm
Dimension of boundary surface between light receiving part and light emitting part: 22 mm × 4 mm
Length L1 of the connecting part in the light emitting part: 50 mm
Projection length L2 of the main body part from the connecting part in the light emitting part: 40 mm
Light exit surface: composed of one plane inclined with respect to the reference plane (however, the inclination direction of the plane constituting the light exit surface is symmetric with the inclination direction of the plane constituting the light receiving surface with respect to the reference plane) .)
Length of light exit surface: 22mm
Number of micro prisms in micro prism group: 168 Prism arrangement pitch: 1.0 mm
Prism step: 0.1 mm
Angle formed between the parallel part and the inclined part in the microprism: 45 °
Length of second light reflecting surface: 28.3 mm
Inclination angle of second light reflecting surface with respect to light emitting surface: 45 °

(2) Light emitting element Type: LED element having an emission wavelength of 392 nm Light emission amount: 500 mW
Number: 15 Arrangement pitch: 10mm

(3) Spherical lens R3, effective diameter: 5mm
Distance from light emitting element: 0.1 mm

<Examples 7 to 9>
The light receiving surface of the light guide is configured by two planes inclined with respect to the reference plane, and the light output surface is configured by two planes inclined with respect to the reference plane (see FIG. 6B). A light source device having the same configuration as in Example 1 was produced. Table 1 below shows the inclination angle θ of each of the two planes constituting the light receiving surface with respect to the reference surface.

<Comparative example 1>
Example except that the light-receiving surface and the light-emitting surface of the light guide are configured by a plane parallel to the reference surface (the inclination angle of the plane constituting each of the light-receiving surface and the light-emitting surface with respect to the reference surface is 0 °). 1 was produced.

[Evaluation]
Each of the light source units according to Examples 1 to 9 and Comparative Example 1 was turned on to form a 6 mm × 10 mm light irradiation region on the inspection object. The light from this light irradiation region was received by the light receiving surface of the light guide and emitted from the light emitting surface. For light emitted from the light exit surface of the light guide, the light flux distribution in the thickness direction of the translucent plate-like body constituting the light guide is measured by the light receiving element, and the amount of light received by the light receiving element and The full width at half maximum of the luminous flux distribution curve was obtained.
The light intensity by the light source unit according to Comparative Example 1 and the half value width of the luminous flux distribution curve are set to 100 (%), and the relative value (%) of the light intensity by the light source unit according to Examples 1 to 9 and the half value width of the luminous flux distribution curve is obtained. Calculated. The results are shown in Table 1 below.
Moreover, the light beam distribution curve figure by the light source unit which concerns on Example 2 and Comparative Example 1 is shown in FIG. In this figure, the vertical axis indicates the relative value (%) of the light beam when the value of the light beam on the light receiving axis (center axis) of the light receiving element is 100%, and the horizontal axis indicates the light irradiation area on the inspection object. The distance from the light receiving axis of the light receiving element is shown.

  As is clear from the results in Table 1, in the light source units according to Examples 1 to 9, it is understood that the light emitted from the light exit surface of the light guide has a large half-value width of the light flux distribution curve. . Therefore, according to the light source units according to the first to ninth embodiments, it is easy to adapt to the detectable angle range of the light receiving element, and the light emitted from the light irradiation region can be appropriately detected by the light receiving element in a wide range. it can.

DESCRIPTION OF SYMBOLS 10 Light source unit 11 Case 12 Light transmissive window 15 Light emitting element 16 Spherical lens 20 Light guide 20a Surface 21 Light receiving part 22 Light receiving surface 22a, 22b Plane 23 First light reflecting surface 24 Micro prism group 24a Micro prism 24b Parallel part 24c Inclined portion 26 Light exit portion 26a Connection portion 26b Main body portion 27 Light exit surfaces 27a and 27b Plane 28 Second light reflecting surface 30 Light receiving element 35 Reflecting mirror 40 Transport mechanism 41 Transport belt 42 Transport roller 70 Housing 71 Insertion port 72 Discharge port 73 Sensor 75 Conveying mechanism 76 Conveying path 80 Light source unit 81, 82 Light emitting element 85 Light guide 86 Light receiving surface 86a, 86b Light condensing part 87, 88 Light reflecting surface 89 Light emitting surface 90 Light receiving element S Reference surface W Inspected object

Claims (3)

The light-transmitting plate-like body having a plurality of side surfaces, formed on one side surface of the light-transmitting plate-like body and extending in one direction, and formed on the other side surface of the light-transmitting plate-like body A light source unit, and a light source unit comprising a plurality of light emitting elements arranged in the same direction as one direction in which a light receiving surface of the light guide extends.
The light receiving unit of the light guide is configured by a plane inclined with respect to a reference plane extending in the one direction perpendicular to the surface of the translucent plate-like body.   The light exit surface of the light guide body extends in the one direction, and the light exit surface is configured by a plane inclined with respect to the reference surface, and an inclination direction of a plane constituting the light exit surface, and the light reception The light source unit according to claim 1, wherein an inclination direction of a plane constituting the surface is symmetrical with respect to the reference plane.   The light source unit according to claim 1, wherein the light guide has an inclination angle of a plane that forms the light receiving surface with respect to the reference surface of 0.5 to 4.5 °. .

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