Detector

Abstract

To provide a detector with an improved accuracy of detecting objects to be detected.SOLUTION: A detector comprises: a mounting substrate on which objects to be detected are mounted; a light guide plate that is arranged overlapping the mounting substrate on one side of a first direction and has light transmissivity; an optical sensor that is arranged overlapping the light guide plate on one side of the first direction and includes a plurality of photodetectors arranged in a planar pattern; and a light source that irradiates the light guide plate with light on a side face in a second direction intersecting the first direction.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a detection device. [Background technology]

[0002] Patent Document 1 discloses a biosensor including an optical sensor having a photosensor (light detection element), a culture vessel placed above the imaging surface of the photosensor, and a point light source arranged above the culture vessel. In the biosensor of Patent Document 1, light irradiated from the point light source passes through the medium and multiple objects to be detected (microorganisms) in the culture vessel and enters the photosensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6830593 Summary of the Invention [Problem to be solved by the invention]

[0004] In the biosensor of Patent Document 1, if the medium in the culture vessel has low light transmittance, it may become difficult to detect the target substance (microorganism).

[0005] An object of the present disclosure is to provide a detection device that improves the detection accuracy of a detection target. [Means for solving the problem]

[0006] A detection device according to one embodiment of the present disclosure includes a mounting substrate on which an object to be detected is mounted, a light guide plate arranged to overlap one side of the mounting substrate in a first direction and having optical transparency, an optical sensor arranged to overlap one side of the light guide plate in the first direction and including a plurality of light detection elements arranged in a planar manner, and a light source arranged adjacent to the light guide plate in a second direction intersecting the first direction and irradiating light onto a side of the light guide plate. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a side view diagrammatically illustrating the detection device according to the first embodiment. [Diagram 2] FIG. 2 is a perspective view illustrating a front light according to the first embodiment. [Figure 3A] FIG. 3A is an enlarged schematic diagram of a cross section of a collimator, which is an example of an optical filter, and a light guide plate. [Figure 3B] FIG. 3B is a schematic diagram showing an enlarged cross section of a louver and a light guide plate, which are an example of an optical filter. [Figure 4] FIG. 4 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. [Diagram 5] FIG. 5 is a side view that illustrates a schematic view of light propagation within the light guide plate. [Figure 6] FIG. 6 is a flowchart illustrating an example of the detection operation of the detection device according to the first embodiment. [Figure 7] FIG. 7 is a side view that illustrates a schematic diagram of a detection device according to a first modified example. [Figure 8] FIG. 8 is a plan view showing a schematic view of a front light according to a second modified example. [Figure 9] FIG. 9 is a perspective view that illustrates a partial cross section of a front light according to a third modified example. [Figure 10] FIG. 10 is a flow chart illustrating an example of the detection operation of the detection device according to the third modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] The form (embodiment) for carrying out the present invention will be described in detail with reference to the drawings. The present disclosure is not limited to the contents described in the following embodiment. The components described below include those that a person skilled in the art can easily imagine and those that are substantially the same. Furthermore, the components described below can be appropriately combined. Note that the disclosure is merely an example, and those that a person skilled in the art can easily imagine appropriate modifications while maintaining the gist of the present disclosure are naturally included in the scope of the present disclosure.

[0009] In addition, in order to clarify the description, the drawings may show the width, thickness, shape, etc. of each part in a schematic manner compared to the actual embodiment, but these are merely examples and do not limit the interpretation of the present disclosure. In addition, in this disclosure and each drawing, elements similar to those described above with respect to the previous drawings may be given the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] In the drawings, the XYZ coordinate system has the Z direction (first direction) as the up-down direction, the X direction (second direction) as the left-right direction, and the Y direction (second direction) as the front-rear direction. The X direction intersects (is perpendicular to) the Y and Z directions, the Y direction intersects (is perpendicular to) the X and Z directions, and the Z direction intersects (is perpendicular to) the X and Y directions. The Z1 side is one side of the first direction, and the Z2 side is the other side of the first direction.

[0011] [First embodiment] First, a first embodiment will be described. Fig. 1 is a side view that shows a schematic diagram of a detection device according to the first embodiment. Fig. 2 is a perspective view that shows a schematic diagram of a front light according to the first embodiment.

[0012] 1 and 2, the detection device 100 includes a mounting substrate 111, a frontlight FL, an optical sensor 81, and an optical filter 82. The frontlight FL includes a light guide plate 2, a light source device 7, and an optical structure 3. In other words, the detection device 100 includes the mounting substrate 111, the light guide plate 2, the light source device 7, the optical structure 3, the optical sensor 81, and the optical filter 82.

[0013] 1, the mounting substrate 111 is a container such as a petri dish and a culture medium. The detection target 114 is a culture medium and a microorganism such as bacteria that is generated in the culture medium, or a sample containing a microorganism. The detection target 114 is not limited to bacteria, and may be other minute objects such as cells.

[0014] As shown in FIG. 1, the light guide plate 2 is disposed so as to overlap the mounting substrate 111 on the Z1 side (one side in the first direction). The light guide plate 2 is translucent. As shown in FIG. 2, the light guide plate 2 is a flat plate-shaped member. The light guide plate 2 has a first surface 21, a second surface 22, and side surfaces 23, 24, 25, and 26. The first surface 21 is a main surface on the Z1 side, and the second surface 22 is a surface on the opposite side to the first surface 21 (i.e., the Z2 side). The side surface 23 is located on the X1 side, the side surface 24 is located on the X2 side, the side surface 25 is located on the Y1 side, and the side surface 26 is located on the Y2 side.

[0015] 1, a reflector 27 is joined to the side surface 24. The reflector 27 reflects light 120 propagating within the light guide plate 2, thereby preventing the light 120 from leaking out of the light guide plate 2 from the side surface 24.

[0016] As shown in FIGS. 1 and 2, the light source device 7 faces the side surface 23 of the light guide plate 2. The light source device 7 is located on the X1 side of the side surface 23 of the light guide plate 2. The light source device 7 irradiates the side surface 23 of the light guide plate 2 with light 120 (see FIG. 4). The light source device 7 is, for example, a plurality of light sources 71. The light source 71 is, for example, a plurality of light emitting diodes (LEDs). That is, the plurality of light sources 71 are lined up along the Y direction and disposed to face the side surface 23 of the light guide plate 2.

[0017] As shown in FIG. 1, the optical structure 3 is provided on the first surface 21 of the light guide plate 2. The optical structure 3 outputs the light 120 (see FIG. 4) incident on the light guide plate 2 to the Z2 side (mounting substrate side). The optical structure 3 is, for example, a scatterer 30 including a convex scatterer 31. In the first embodiment, an example in which the convex scatterer 31 is applied as the optical structure 3 will be described. The convex scatterer 31 is a semispherical light-transmitting member protruding from the first surface 21 of the light guide plate 2 to the Z1 side. That is, as viewed from the Z direction, the convex scatterer 31 has a circular shape having a first diameter d. Note that, in the present invention, the shape of the convex scatterer 31 as viewed from the Z direction is not limited to a circular shape, and may include other shapes, such as a polygonal shape. A part of the light 120 propagating through the light guide plate 2 is scattered by the convex scatterer 31. Convex scatterers 31, as shown in Fig. 2, are arranged in a matrix along the X and Y directions. The distance between a pair of convex scatterers 31 adjacent in the X direction is distance L, and the distance between a pair of convex scatterers 31 adjacent in the Y direction is also distance L. In this manner, the multiple convex scatterers 31 are arranged at equal intervals in the X and Y directions. Furthermore, the distance L, which is the minimum value of the distance between the convex scatterers 31, is three times or more the first diameter d. Note that the scatterer 30 may be concave instead of convex.

[0018] 1, the optical sensor 81 and the optical filter 82 are arranged to overlap on the Z1 side with respect to the light guide plate 2. The optical sensor 81 is arranged on the Z1 side with respect to the optical filter 82. That is, the optical filter 82 is arranged between the optical sensor 81 and the light guide plate 2. The optical sensor 81 will be described later.

[0019] Next, the optical filter 82 will be described. The optical filter 82 is an optical element that transmits a component of the light 120 reflected by the object 114 and traveling in the Z direction toward the optical sensor 81. The optical filter 82 includes a light shielding portion and a light guiding portion, and the light shielding portion has a higher light absorption rate than the light guiding portion. The optical filter 82 is exemplified by a collimator 82A (collimator aperture) shown in FIG. 3A and a louver 82B shown in FIG. 3B. FIG. 3A is a schematic diagram showing an enlarged cross section of a collimator and a light guiding plate, which are examples of an optical filter. FIG. 3B is a schematic diagram showing an enlarged cross section of a louver and a light guiding plate, which are examples of an optical filter.

[0020] 3A, the collimator 82A includes a cylindrical hole 82A1 (light guiding portion) extending along the Z direction. The hole 82A1 transmits the light 120 reflected by the detection object 114 toward the optical sensor 81. The diameter D1 (the maximum distance along the X direction in the cross section) of the hole 82A1 is larger than the first diameter d of the convex scatterer 31.

[0021] As shown in FIG. 3B, the louver 82B includes a plate-shaped light-shielding portion 82B2 and a light-guiding portion 82B1. The light-shielding portion 82B2 and the light-guiding portion 82B1 extend in the Z direction. The light-shielding portion 82B2 and the light-guiding portion 82B1 are alternately arranged along the X direction. The light-shielding portion 82B2 has a higher light absorption rate than the light-guiding portion 82B1. The light-guiding portion 82B1 transmits the light 120 reflected by the object to be detected 114 toward the optical sensor 81. The thickness D2 of the light-guiding portion 82B1 along the X direction (the maximum distance along the X direction in the cross section) is greater than the first diameter d of the convex scatterer 31.

[0022] Fig. 4 is a block diagram showing an example of the configuration of the detection device according to the first embodiment. As shown in Fig. 4, the detection device 100 has an optical sensor 81, a light source device 7, and a host IC 75 that controls the light source device 7. The optical sensor 81 has an array substrate 811, a plurality of sensor pixels 812 (photodiodes 813) formed on the array substrate 811, gate line driving circuits 814A and 814B, a signal line driving circuit 815A, and a detection control circuit 816.

[0023] The array substrate 811 is formed using a substrate as a base. Each of the sensor pixels 812 includes a photodiode 813, a plurality of transistors, and various wirings.

[0024] The array substrate 811 has a detection area AA and a peripheral area GA. The detection area AA is an area in which a plurality of sensor pixels 812 (a plurality of photodiodes 813) are provided. The peripheral area GA is an area between the outer periphery of the detection area AA and the outer edge of the array substrate 811, and is an area in which the plurality of sensor pixels 812 are not provided. The gate line driving circuits 814A and 814B, the signal line driving circuit 815A, and the detection control circuit 816 are provided in the peripheral area GA.

[0025] Each of the sensor pixels 812 is an optical sensor having a photodiode 813 as a sensor element. Each of the photodiodes 813 outputs an electrical signal according to the light irradiated thereon.

[0026] The detection control circuit 816 is a circuit that supplies control signals Sa, Sb, and Sc to the gate line driving circuits 814A and 814B and the signal line driving circuit 815A, respectively, and controls their operations. The detection control circuit 816 includes a signal processing circuit that processes the detection signals Vdet from the multiple photodiodes 813.

[0027] The detection control circuit 816 processes the detection signals Vdet from the multiple photodiodes 813, and outputs a sensor value So based on the detection signal Vdet to the host IC 75. In this way, the detection device 100 detects information related to the object 114 to be detected.

[0028] The light source device 7 includes a light source 71 and a light-emitting element control circuit 74 .

[0029] As described above, the multiple light sources 71 are positioned to face the side surface 23 of the light guide plate 2. The multiple light sources 71 are driven by switching between on (lighted state) and off (non-lighted state) in response to a command Sd from the light-emitting element control circuit 74.

[0030] The host IC 75 has a sensor value storage circuit 751, a sensor value calculation circuit 752, a light amount setting circuit 753, a target value storage circuit 759, a memory circuit 757, and a host PC 758 as control circuits on the optical sensor 81 side. The sensor value storage circuit 751 stores the sensor value So output from the detection control circuit 816 of the optical sensor 81. The sensor value calculation circuit 752 performs a predetermined calculation process on the sensor value So of the photodiode 813.

[0031] In the light amount setting mode, the light amount setting circuit 753 compares the sensor value So detected by the multiple photodiodes 813 with a preset target sensor value So-t acquired from the target value storage circuit 759, and sets the light amounts for detection of the multiple light sources 71. The target value storage circuit 759 stores the preset target sensor value So-t.

[0032] The host IC 75 has, as control circuits on the light source device 7 side, a lighting pattern generating circuit 754 and a lighting pattern storage circuit 755. The lighting pattern storage circuit 755 stores information on the light intensity of each of the multiple light sources 71 in the light intensity setting mode.

[0033] The lighting pattern generating circuit 754 generates various control signals based on the information on the amount of light in the lighting pattern storage circuit 755 .

[0034] In the detection mode, the image generating circuit 756 generates an image of the detection target 114 based on the sensor values ​​So output from the multiple photodiodes 813.

[0035] The host IC 75 further includes a memory circuit 757. The memory circuit 757 stores base image data obtained by detecting light irradiated from the light source 71 by the optical sensor 81 in a state where the detection target 114 is not mounted on the mounting substrate 111. The base image data may be substantially similar in reflectance to a mounting substrate having nothing mounted thereon. That is, for example, the base image data may be detected by placing an object having a uniform reflectance within the detection surface (for example, a black or white board).

[0036] Next, the propagation of light in the light guide plate will be described. FIG. 5 is a side view showing the propagation of light in the light guide plate. As shown in FIG. 5, light 120 emitted from the light source 71 enters the inside of the light guide plate 2 from the side surface 23 of the light guide plate 2, and propagates through the light guide plate 2 while repeating total reflection at the first surface 21 and the second surface 22. A part of the light 120 propagating through the light guide plate 2 becomes scattered light 121 by the convex scatterer 31. A part of the scattered light 121, light 123, is emitted from the second surface 22 of the light guide plate 2 to the object to be detected 114, reflected by the object to be detected 114, and is irradiated to a plurality of photodiodes 813 of the optical sensor 81 through the light guide plate 2 and the optical filter 82. The scattered light 121 scattered by the convex scatterer 31 includes light 122 emitted to the object to be detected 114 as well as light 123 emitted to the optical filter 82 facing the light guide plate 2.

[0037] Next, a detection operation example of the detection device will be described with reference to Fig. 6 etc. Fig. 6 is a flow chart diagram showing a detection operation example of the detection device according to the first embodiment.

[0038] First, the light source device 7 turns on the light source 71 based on a control signal from the lighting pattern generating circuit 754 (see FIG. 4) (step S101).

[0039] Next, base image data is generated by detecting light emitted from the light source 71 by the optical sensor 81 in a state where the detection object 114 is not mounted on the mounting substrate 111 (step S102). The base image data is stored in the memory circuit 757 (see FIG. 4).

[0040] Next, differential image data is calculated (step S103). The differential image data is data obtained by subtracting the base image data from the captured image data. Specifically, captured image data obtained by detection by the optical sensor 81 when the detectable object 114 is mounted on the mounting substrate 111 is acquired, and differential image data indicating the detection result when the detectable object 114 is mounted on the mounting substrate 111 is acquired from the difference between the base image data and the captured image data. The differential image data is calculated by the image generation circuit 756 (see FIG. 4). The differential image data is then transferred to the host PC (step S104).

[0041] As described above, the detection device 100 includes a mounting substrate 111 on which the object to be detected 114 is mounted, a light guide plate 2, an optical sensor 81 including a plurality of photodiodes (light detection elements) 813, and a light source 71 that irradiates light 120 onto the side surface 23 of the light guide plate 2.

[0042] As mentioned above, in Patent Document 1, the culture medium, which serves as the mounting substrate, and the object to be detected are placed between the optical sensor and the light source, so if the mounting substrate has low translucency, it may be difficult to detect the object to be detected.

[0043] In contrast, in this embodiment, the light source 71 is disposed on the side surface 23 of the light guide plate 2, the optical sensor 81 is disposed on the first surface 21 side of the light guide plate 2, and the object to be detected 114 is disposed on the second surface 22 side of the light guide plate 2. Therefore, regardless of the degree of translucency of the mounting substrate 111, the light 120 reflected by the object to be detected 114 passes through the light guide plate 2 and reaches the photodiode (photodetector) 813. Therefore, according to this embodiment, it is possible to provide a detection device 100 that improves the accuracy of detecting the object to be detected 114.

[0044] The light guide plate 2 is provided with an optical structure 3 that emits light 120 toward the mounting substrate 111. The light 120 emitted from the light source 71 enters the light guide plate 2 from the side surface 23 of the light guide plate 2, and propagates through the light guide plate 2 while repeatedly being totally reflected at the first surface 21 and the second surface 22. Therefore, by providing the optical structure 3, it is possible to emit a part of the light 120 toward the mounting substrate 111. The light 120 emitted toward the mounting substrate 111 is reflected by the object to be detected 114, passes through the light guide plate 2, and reaches the photodiode (photodetector) 813. This improves the detection accuracy of the object to be detected 114.

[0045] The optical structure 3 is not limited to the convex scattering body 31 or the concave scattering body 32 described later, but may be a structure formed by jetting ink dots or a structure formed by machining such as cutting.

[0046] The optical structures 3 are provided on a first surface 21 of the light guide plate 2 on the optical sensor 81 side.

[0047] This allows the light 120 propagating within the light guide plate 2 to be emitted towards the object to be detected 114 on the opposite side to the optical sensor 81, thereby improving the detection accuracy of the object to be detected 114.

[0048] The optical structure 3 is a scatterer 30 that scatters the light 120 propagating through the light guide plate 2. In this way, the scatterer 30 scatters the light 120, so that the light 120 propagating through the light guide plate 2 can be emitted toward the object to be detected 114 on the opposite side to the optical sensor 81. This improves the detection accuracy of the object to be detected 114.

[0049] The scatterer 30 is circular and has a first diameter d when viewed from the Z direction. The minimum distance L between any two adjacent scatterers 30 among the plurality of scatterers 30 is three times or more the first diameter d.

[0050] When multiple scatterers 30 are densely arranged, light 120 reflected by the object to be detected 114, transmitted through the light guide plate 2, and directed toward the photodiode (photodetector element) 813 is diffused again by the dense scatterers 30, and the amount of light 120 that reaches the photodiode 813 is reduced. Therefore, it is desirable to reduce the density of the multiple scatterers 30. For example, it is desirable that the minimum distance L between two adjacent scatterers 30 is three times or more the first diameter d. The relationship of the above distances, diameters, thicknesses, and the like is summarized as distance L>diameter D1 (thickness D2)>3d.

[0051] Between the light guide plate 2 and the optical sensor 81, an optical filter 82 is provided.

[0052] The optical filter 82 allows more of the light 120 reflected by the object 114 and transmitted through the light guide plate 2 to be directed toward the photodiode 813. This makes it possible to further improve the accuracy of detecting the object 114.

[0053] The optical filter 82 includes a light shielding portion and a light guiding portion, and the light shielding portion has a higher light absorption rate than the light guiding portion. The optical filter 82 is, for example, a collimator 82A including a cylindrical hole 82A1 (light guiding portion). The scatterer 30 is circular and has a first diameter d when viewed from the Z direction. The diameter D1 (maximum distance along the X direction) of the hole 82A1 (light guiding portion) is larger than the first diameter d.

[0054] According to this, the light 120 reflected by the object to be detected 114 and transmitted through the light guide plate 2 can more easily pass through the hole 82A1 of the collimator 82A, so that the detection accuracy of the object to be detected 114 can be further improved.

[0055] Optical filter 82 includes louver 82B. A thickness D2 (maximum distance along the X direction) of light guiding portion 82B1 is greater than a first diameter d of scattering body 30. This allows light 120 reflected by object to be detected 114 and transmitted through light guiding plate 2 to more easily pass through light guiding portion 82B1 of louver 82B, thereby making it possible to further improve the detection accuracy of object to be detected 114.

[0056] The image processing device includes a storage circuit 757 that stores base image data, and an image generating circuit 756 that acquires differential image data from the difference between the base image data and the captured image data.

[0057] The captured image data is data obtained by detecting light irradiated from a light source by the optical sensor 81 when the detectable object 114 is mounted on the mounting substrate 111. The captured image data includes base image data obtained by detecting by the optical sensor 81 when the detectable object 114 is not mounted on the mounting substrate 111. In other words, the base image data does not include data in which the light reflected from the detectable object 114 is detected by the optical sensor 81. Therefore, since differential image data is obtained from the difference between the base image data and the captured image data, the detection device 100 according to this embodiment can obtain higher detection accuracy.

[0058] [First Modification] Next, a first modified example will be described. Fig. 7 is a side view that shows a schematic diagram of a detection device according to the first modified example. The detection device 100A according to the first modified example is different from the detection device 100 according to the first embodiment in the shape of the optical structure 3 (scattering body 30). The first modified example will be described below with a focus on the optical structure 3.

[0059] As shown in Fig. 7, the optical structure 3 (scatterer 30) provided in the frontlight FL-1 according to the first modified example is a concave scatterer 32. The concave scatterer 32 is a semispherical depression (dent) recessed from the first surface 21 of the light guide plate 2 toward the Z2 side. When viewed from the Z direction, the concave scatterer 32 has a first diameter d. A portion of the light 120 propagating within the light guide plate 2 is scattered by the concave scatterer 32. The concave scatterers 32 are arranged at equal intervals in a matrix along the X direction and the Y direction, similar to the convex scatterers 31.

[0060] As described above, the scatterer 30 is the concave scatterer 32 that scatters the light 120 propagating through the light guide plate 2. Like the convex scatterer 31 of the first embodiment, the concave scatterer 32 scatters a part of the light 120 propagating through the light guide plate 2, and can emit the light 120 propagating through the light guide plate 2 toward the object to be detected 114 on the opposite side to the optical sensor 81. This improves the detection accuracy of the object to be detected 114.

[0061] [Second modified example] Next, a description will be given of a second modified example. Fig. 8 is a plan view showing a schematic view of a front light according to the second modified example.

[0062] A detection device 100B according to the second modification is different from the detection device 100 according to the first embodiment in the density at which the optical structures 3 (scatterers 30) are arranged. The second modification will be described below, focusing on the optical structures 3.

[0063] 8, the optical structure 3 provided in the frontlight FL-2 according to the second modified example is a convex scattering body 31 A. The convex scattering body 31A is a hemispherical convex portion protruding from the first surface 21 of the light guide plate 2 to the Z1 side.

[0064] In a plan view of the light guide plate 2 from the Z1 side, the light guide plate 2 has rectangular regions 201, 202, 203, and 204, each of which has the same area. Specifically, the regions 201, 202, 203, and 204 are arranged in this order from the X1 side to the X2 side.

[0065] In region 201, multiple convex scatterers 31A are arranged in a matrix in the X and Y directions. The distance between adjacent convex scatterers 31A in the X direction is distance L1. The distance between adjacent convex scatterers 31A in the Y direction is also distance L1. In region 201, the convex scatterers 31A are arranged in 9 rows and 3 columns. Therefore, the number of convex scatterers 31A included in region 201 is 27.

[0066] In region 202, multiple convex scatterers 31A are arranged in a matrix in the X and Y directions. The distance between adjacent convex scatterers 31A in the X direction is distance L2. The distance between adjacent convex scatterers 31A in the Y direction is also distance L2. In region 202, the convex scatterers 31A are arranged in 11 rows and 3 columns. Therefore, the number of convex scatterers 31A included in region 202 is 33.

[0067] In region 203, multiple convex scatterers 31A are arranged in a matrix in the X and Y directions. The distance between adjacent convex scatterers 31A in the X direction is distance L3. The distance between adjacent convex scatterers 31A in the Y direction is also distance L3. In region 203, the convex scatterers 31A are arranged in 13 rows and 3 columns. Therefore, the number of convex scatterers 31A included in region 203 is 39.

[0068] In region 204, multiple convex scatterers 31A are arranged in a matrix in the X and Y directions. The distance between adjacent convex scatterers 31A in the X direction is distance L4. The distance between adjacent convex scatterers 31A in the Y direction is also distance L4. In region 204, the convex scatterers 31A are arranged in 16 rows and 4 columns. Therefore, the number of convex scatterers 31A included in region 204 is 64. In this way, 27 convex scatterers 31A are provided in region 201, 33 in region 202, 39 in region 203, and 64 in region 204.

[0069] Here, if one of the regions 201, 202, 203, and 204 is defined as a first region, and the region located on the X2 side of the first region is defined as a second region, the number of convex scatterers 31A included in the second region is greater than the number of convex scatterers 31A included in the first region. For example, if the region 202 is defined as a first region and the region 204 is defined as a second region, the number of convex scatterers 31A (64) included in the region 204, which is the second region, is greater than the number of convex scatterers 31A (33) included in the region 202, which is the first region. The arrangement density of the scatterers 30 may be increased in a gradational manner. That is, the arrangement density of the scatterers 30 may be gradually increased from the X1 side toward the X2 side.

[0070] As described above, the first surface 21 of the light guide plate 2 has a first region and a second region. The number of scatterers 30 included in the second region is greater than the number of scatterers 30 included in the first region.

[0071] In other words, the arrangement density of the scatterers 30 increases as the distance from the light source (light source) 71 increases. The scatterers 30 have the effect of emitting the light 120 propagating within the light guide plate 2 toward the detection object 114 side opposite the optical sensor 81 side.

[0072] Here, the amount of light 120 propagating through the light guide plate 2 decreases as the distance from the light source (light source) 71 increases. Therefore, by increasing the arrangement density of the scatterers 30 as the distance from the light source (light source) 71 increases, it is possible to improve the detection accuracy of the object 114 even with a small amount of light 120.

[0073] [Third Modification] Next, a third modified example will be described. Fig. 9 is a perspective view showing a schematic cross section of a part of a front light according to the third modified example. Fig. 10 is a flow chart showing an example of a detection operation of a detection device according to the third modified example.

[0074] As shown in FIG. 9, the detection device 100C according to the third modification includes a front light FL-3. The front light FL-3 includes a light source device 7A. The light source device 7A includes three light sources (light sources) 71A. Specifically, the light source 71A includes a light source (first light source) 71A-1, a light source (second light source) 71A-2, and a light source (third light source) 71A-3. The first light source 71A-1 emits a first light. The second light source 71A-2 emits a second light having a wavelength band different from that of the first light. The third light source 71A-3 emits a third light having a wavelength band different from that of the first light and the second light. The first light corresponds to, for example, red, and the wavelength band of the first light is 610 nm or more and 780 nm or less. The second light corresponds to, for example, green, and the wavelength band of the second light is 500 nm or more and 570 nm or less. The third light corresponds to, for example, blue, and the wavelength band of the third light is not less than 460 nm and not more than 500 nm.

[0075] Furthermore, the first period during which the light source (first light source) 71A-1 is turned on, the second period during which the light source (second light source) 71A-2 is turned on, and the third period during which the light source (third light source) 71A-3 is turned on are all different from one another.

[0076] The image data based on the light detected by the optical sensor 81 in the first period is referred to as first data. The image data based on the light detected by the optical sensor 81 in the second period is referred to as second data. The image data based on the light detected by the optical sensor 81 in the third period is referred to as third data. The image generation circuit 756 (see FIG. 4) combines the first data, the second data, and the third data to obtain a detection result of the state in which the object to be detected 114 is mounted on the mounting substrate 111.

[0077] Next, with reference to FIG. 10 and other figures, a detection operation example of the detection device according to the third modified example will be described.

[0078] First, the lighting pattern generating circuit 754 (see FIG. 4) transmits a signal to light the light source (first light source) 71A-1 (step S201).

[0079] Next, the image generating circuit 756 (see FIG. 4) generates first base image data based on the signal from the sensor value storage circuit 751, and stores it in the storage circuit 757 (step S202).

[0080] The lighting pattern generating circuit 754 transmits a signal to light the light source (second light source) 71A-2 (step S203).

[0081] Next, the image generating circuit 756 generates second base image data based on the signal from the sensor value storage circuit 751, and stores it in the storage circuit 757 (step S204).

[0082] The lighting pattern generating circuit 754 transmits a signal to light the light source (third light source) 71A-3 (step S205).

[0083] Next, the image generating circuit 756 generates third base image data based on the signal from the sensor value storage circuit 751, and stores it in the storage circuit 757 (step S206).

[0084] The lighting pattern generating circuit 754 transmits a signal to turn on the light source (first light source) 71A-1 (step S207).

[0085] The image generating circuit 756 generates the first captured image data based on the signal from the sensor value storage circuit 751, and stores it in the storage circuit 757 (step S208).

[0086] The lighting pattern generating circuit 754 transmits a signal to light the light source (second light source) 71A-2 (step S209).

[0087] The image generating circuit 756 generates second captured image data based on the signal from the sensor value storage circuit 751, and stores the second captured image data in the storage circuit 757 (step S210).

[0088] The lighting pattern generating circuit 754 transmits a signal to turn on the light source (third light source) 71A-3 (step S211).

[0089] The image generating circuit 756 generates third captured image data based on the signal from the sensor value storage circuit 751, and stores the third captured image data in the storage circuit 757 (step S212).

[0090] The image generating circuit 756 calculates the first data=[first captured image data]-[first base image data] (step S213). The first data is differential image data obtained by subtracting the first base image data from the first captured image data. The first data is calculated by the image generating circuit 756.

[0091] The image generating circuit 756 stores the first data in the memory circuit 757 (step S214).

[0092] The image generating circuit 756 calculates the second data=[second captured image data]-[second base image data] (step S215). The second data is differential image data obtained by subtracting the second base image data from the second captured image data. The second data is calculated by the image generating circuit 756.

[0093] The image generating circuit 756 stores the second data in the memory circuit 757 (step S216).

[0094] The image generating circuit 756 calculates the third data=[third captured image data]-[third base image data] (step S217). The third data is differential image data obtained by subtracting the third base image data from the third captured image data. The third data is calculated by the image generating circuit 756.

[0095] The image generating circuit 756 stores the third data in the memory circuit 757 (step S218).

[0096] The image generating circuit 756 synthesizes the first data, the second data, and the third data to generate full-color image data, and stores the generated data in the storage circuit 757 (step S219).

[0097] The image generating circuit 756 transfers the full-color image data to the host PC 758 (see FIG. 4) (step S220).

[0098] As described above, the light source (light source) 71A includes the light source (first light source) 71A-1, the light source (second light source) 71A-2, and the light source (third light source) 71A-3.

[0099] The optical sensor 81 also includes an image generating circuit 756 that combines first data based on the light detected by the optical sensor 81 in the first period, second data based on the light detected by the optical sensor 81 in the second period, and third data based on the light detected by the optical sensor 81 in the third period to obtain a detection result of the state in which the object to be detected 114 is mounted on the mounting substrate 111.

[0100] According to this, data of three images using the light from the three light sources 71A can be obtained, and the data of the three images can be combined to obtain a detection result of the state in which the detection target 114 is mounted on the mounting substrate 111. Therefore, higher detection accuracy can be obtained compared to the case where data of an image using the light from one light source 71 is used. [Explanation of symbols]

[0101] 2 Light guide plate 3 Optical structure 7, 7A light source device 21 Page 1 22 Side 2 23 Side 30 Scatterer 31 Convex scatterer 31A Convex scatterer 32 Concave scatterer 71, 71A light source (light source) 71A-1 Light source (1st light source) 71A-2 Light source (second light source) 71A-3 Light source (3rd light source) 81 Optical Sensor 82 Optical Filters 100, 100A, 100B, 100C Detector 111 Mounting board 114 Detectable object 120 light 121 Scattered light 201 areas 202 areas 203 areas 204 areas 813 Photodiode (light detection element) d 1st diameter D1 Hole diameter D2 Thickness of the light guide FL Front Light FL-1 Front Light FL-2 Front Light FL-3 Front Light

Claims

1. A mounting substrate on which an object to be detected is mounted; a light guide plate having translucency and disposed on one side of the mounting substrate in a first direction so as to overlap the mounting substrate; an optical sensor including a plurality of light detection elements arranged in a planar manner and overlapping one side of the light guide plate in the first direction; a light source disposed adjacent to the light guide plate in a second direction intersecting the first direction, the light source irradiating light onto a side surface of the light guide plate.

2. The light guide plate is provided with an optical structure that outputs the light incident from the light source to the mounting substrate side. The detection device according to claim 1 .

3. A plurality of the optical structures are provided, and the plurality of the optical structures are provided on a first surface of the light guide plate on a side of the optical sensor.

3. The detection device according to claim 2.

4. The optical structure is a scattering body that scatters the light when the light propagating through the light guide plate reaches the scattering body.

4. The detection device according to claim 3.

5. the first surface of the light guide plate has a first region and a second region having the same area and spaced apart from the light source on one side in the second direction; the second region is located on one side of the first region in the second direction, The number of the scatterers included in the second region is greater than the number of the scatterers included in the first region.

5. The detection device according to claim 4.

6. the scatterer is circular and has a first diameter when viewed from the first direction; A minimum value of a distance between two adjacent scatterers among the plurality of scatterers is three times or more the first diameter.

5. The detection device according to claim 4.

7. An optical filter is provided between the light guide plate and the optical sensor.

5. The detection device according to claim 4.

8. the scatterer is circular and has a first diameter when viewed from the first direction; the optical filter includes a light shielding portion and a light guiding portion, the light shielding portion having a higher absorption rate of the light than the light guiding portion, A maximum distance of the light guiding portion along the second direction is greater than the first diameter of the scatterer.

8. The detection device according to claim 7.

9. The light source is The illumination device includes a first light source that irradiates a first light, a second light source that irradiates a second light having a different wavelength band from the first light, and a third light source that irradiates a third light having a different wavelength band from the first light and the second light.

5. The detection device according to claim 4.

10. a memory circuit that stores base image data obtained by detecting light irradiated from the light source by the optical sensor in a state in which the detection object is not mounted on the mounting substrate; an image generating circuit that obtains captured image data obtained by detecting light irradiated from the light source with the optical sensor while the detectable object is mounted on the mounting substrate, and obtains differential image data indicating a detection result of the state in which the detectable object is mounted on the mounting substrate from a difference between the base image data and the captured image data; 5. The detection device according to claim 4.

11. a first period during which the first light source is turned on, a second period during which the second light source is turned on, and a third period during which the third light source is turned on are different from each other; an image generating circuit that combines first data based on the light detected by the optical sensor in the first period, second data based on the light detected by the optical sensor in the second period, and third data based on the light detected by the optical sensor in the third period to obtain a detection result of a state in which the detection object is mounted on the mounting substrate; 10. The detection device according to claim 9.

12. A light guide plate having light transmissivity; an optical sensor including a plurality of light detection elements arranged in a planar manner and overlapping one side of the light guide plate in a first direction; a light source disposed adjacent to the light guide plate in a second direction intersecting the first direction and configured to irradiate light onto a side surface of the light guide plate; an optical structure provided on the light guide plate and configured to emit the light incident from the light source to the other side in the first direction.

13. a memory circuit for storing base image data detected by placing an object having a uniform reflectance on a detection surface; an image generating circuit that acquires captured image data obtained by detecting light irradiated from the light source with the optical sensor while the detectable object is mounted on the mounting substrate, and acquires differential image data indicating a detection result of the state in which the detectable object is mounted on the mounting substrate from a difference between the base image data and the captured image data; 13. The detection device of claim 12.

Images