Detection device

Abstract

To provide a detection device that improves the accuracy of detection of objects to be detected.SOLUTION: A detection device includes a light guide plate, a plurality of light diffusion structures, an optical sensor, and a light source. The plurality of light diffusion structures include a first structure, a second structure, a third structure, and a fourth structure. A first side connecting a first center of the first structure and a second center of the second structure, a second side connecting the first center and a third center of the third structure, and a third side connecting the second center and the third center form a first isosceles triangle in which the first side is a base and the second side and the third side are equal sides. A fourth side connecting a fourth center of the fourth structure and the second center, a fifth side connecting the fourth center and the third center, and the third side form a second isosceles triangle in which the fifth side is a base and the third side and the fourth side are equal sides. The first isosceles triangle and the second isosceles triangle form a parallelogram having the first center, the second center, the third center, and the fourth center as vertices.SELECTED DRAWING: Figure 3

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a biosensor including an optical sensor having a photodiode (light detection element), a culture vessel placed on the upper side of the imaging surface of the optical sensor, and a point light source arranged on the upper side of the culture vessel. The culture vessel contains a culture medium and a plurality of analytes (microorganisms). In the biosensor of Patent Document 1, the light irradiated from the point light source passes through the culture medium and the plurality of analytes (microorganisms) in the culture vessel and is incident on the photodiode. However, in the biosensor of Patent Document 1, when the light transmittance of the culture medium in the culture vessel is low, it may be difficult to detect the analyte.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is a need for a detection device with higher detection accuracy of analytes.

[0005] An object of the present disclosure is to provide a detection device with improved detection accuracy of analytes.

Means for Solving the Problems

[0006] The detection device according to one aspect of the present disclosure includes a light guide plate having translucency, a plurality of light diffusion structures provided on one surface of the light guide plate in a first direction, an optical sensor including a plurality of light detection elements arranged to overlap and arranged in a planar manner on one side of the light guide plate in the first direction, and a light source arranged adjacent to the light guide plate in a second direction intersecting the first direction and irradiating light on a side surface of the light guide plate. When viewed from the first direction, the plurality of light diffusion structures include a first structure, a second structure adjacent to the first structure, a third structure adjacent to the first structure and the second structure, and a fourth structure adjacent to the second structure and the third structure. With respect to a straight line passing through the second structure and the third structure, the first structure is located on the opposite side of the fourth structure. A first side connecting a first center of the first structure and a second center of the second structure, a second side connecting the first center and a third center of the third structure, and a third side connecting the second center and the third center form a first isosceles triangle having the first side as a base and the second side and the third side as equal sides. A fourth side connecting a fourth center of the fourth structure and the second center, a fifth side connecting the fourth center and the third center, and the third side form a second isosceles triangle having the fifth side as a base and the third side and the fourth side as equal sides. The first isosceles triangle and the second isosceles triangle form a parallelogram having the first center, the second center, the third center, and the fourth center as vertices. In the parallelogram, the first side and the fifth side are parallel, and the second side and the fourth side are parallel. All four interior angles of the parallelogram are obtuse or acute angles.

Brief Description of the Drawings

[0007]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5A

Fig. 5B

Fig. 6

Fig. 7A

Fig. 7B

Fig. 8

Fig. 9

Fig. 10

Embodiments for Carrying Out the Invention

[0008] Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. The present disclosure is not limited by the content described in the following embodiments. Further, the constituent elements described below include those that can be easily assumed by those skilled in the art and substantially the same ones. Furthermore, the constituent elements described below can be combined as appropriate. Note that the disclosure is merely an example, and those that can be easily conceived by those skilled in the art with appropriate modifications while maintaining the gist of the present disclosure are naturally included in the scope of the present disclosure.

[0009] In addition, for the purpose of making the description clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment, but this is merely an example and does not limit the interpretation of the present disclosure. Also, in the present disclosure and each figure, elements similar to those described above with respect to the previously shown figures may be denoted by the same reference numerals, and detailed descriptions may be omitted as appropriate.

[0010] And in the drawings, for the XYZ coordinates, the Z direction (first direction) is the vertical direction, the X direction (second direction) is the left - right direction, and the Y direction is the front - back direction. The X direction intersects (is orthogonal to) the Y direction and the Z direction, the Y direction intersects (is orthogonal to) the X direction and the Z direction, and the Z direction intersects (is orthogonal to) the X direction and the Y direction. The Z1 side is one side of the first direction, and the Z2 side is the other side of the first direction. The X1 side is one side of the second direction, and the X2 side is the other side of the second direction.

[0011] [Embodiment] The detection device according to the embodiment will be described. FIG. 1 is a side view schematically showing the detection device according to the embodiment.

[0012] As shown in FIG. 1, the detection device 100 includes a detected object installation part 111, a front light FL, an optical sensor 81, and an optical filter 82. The front light FL includes a light guide plate 2, a light source device 7, and a light diffusion structure 3. That is, in other words, the detection device 100 includes a detected object installation part 111, a light guide plate 2, a light source device 7, a light diffusion structure 3, an optical sensor 81, and an optical filter 82.

[0013] The detected object installation part 111 is a container such as a petri dish and a culture medium. The detected object installation part 111 installs the detected object 114. The detected object 114 is a culture medium and microorganisms such as bacteria generated in the culture medium, or a sample containing microorganisms. The detected object 114 is not limited to bacteria and may be other microscopic objects such as cells.

[0014] The light guide plate 2 is arranged to overlap the detected object installation part 111 on the Z1 side (one side of the first direction). In other words, the detected object installation part 111 is arranged to overlap the light guide plate 2 on the Z2 side (the other side of the first direction) and installs the detected object 114. The light guide plate 2 has translucency. 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. The first surface 21 is the main surface on the Z1 side, and the second surface 22 is the surface on the side opposite to the first surface 21 (i.e., the Z2 side). The side surface 23 is located on the X1 side, and the side surface 24 is located on the X2 side.

[0015] A reflecting plate 27 is joined to the side surface 24 of the light guide plate 2. The reflecting plate 27 suppresses the leakage of the light 120 (see FIG. 9) from the side surface 24 to the outside of the light guide plate 2 by reflecting the light 120 propagating in the light guide plate 2.

[0016] 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 with respect to 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 the light 120 (see FIG. 9). 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: Light Emitting Diodes). That is, the plurality of light sources 71 are arranged along the Y direction and are arranged to face the side surface 23 of the light guide plate 2.

[0017] As shown in Fig. 1, a plurality of light diffusion structures 3 are provided on the first surface 21 of the light guide plate 2. The light diffusion structure 3 emits the light 120 incident on the light guide plate 2 to the Z2 side (the side of the object placement part). The light diffusion structure 3 is, for example, a scattering body including convex scattering bodies. The convex scattering body is a hemispherical translucent member protruding from the first surface 21 of the light guide plate 2 toward the Z1 side. That is, when viewed from the Z direction, the convex scattering body has a circular shape with a diameter d. In the present invention, the shape of the light diffusion structure 3 when viewed from the Z direction is not limited to a circular shape, and other shapes such as polygons are also included. A part of the light 120 propagating in the light guide plate 2 is scattered by the light diffusion structure 3. Note that the light diffusion structure 3 may be a hemispherical concave shape provided on the first surface 21 of the light guide plate 2 and recessed toward the Z2 side. The arrangement of the light diffusion structure 3 will be described in detail later.

[0018] As shown in Fig. 1, the optical sensor 81 and the optical filter 82 are arranged to overlap the light guide plate 2 on the Z1 side. 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 includes a plurality of photodiodes 813 (light detection elements) arranged in a planar shape. The optical filter 82 will be described later.

[0019] Next, the arrangement of the plurality of light diffusion structures 3 when viewed from the Z direction will be described. Fig. 2 is a schematic diagram showing the arrangement of the light diffusion structure according to the embodiment.

[0020] As shown in Fig. 2, the plurality of light diffusion structures 3 provided on the first surface 21 of the light guide plate 2 include, for example, a first structure 31, a second structure 32, a third structure 33, a fourth structure 34, a fifth structure 35, a sixth structure 36, a seventh structure 37, an eighth structure 38, a ninth structure 39, a tenth structure 40, and an eleventh structure 41 when viewed from the Z direction. In the first region 201 shown by the solid line, the first structure 31, the second structure 32, the third structure 33, the fourth structure 34, the fifth structure 35, and the sixth structure 36 are arranged. In the second region 202 shown by the broken line, the seventh structure 37, the eighth structure 38, the second structure 32, the ninth structure 39, the fourth structure 34, and the tenth structure 40 are arranged.

[0021] In addition, in FIGS. 2 to 6, vertical grid lines and horizontal grid lines are described to make the arrangement of the light diffusion structure 3 easier to understand. Specifically, a first grid line 131 extending in the X direction and a second grid line 132 extending in the Y direction are described. The plurality of first grid lines 131 are arranged at equal intervals in the Y direction. The plurality of second grid lines 132 are arranged at equal intervals in the X direction. The plurality of first grid lines 131 and the plurality of second grid lines 132 intersect to form a plurality of squares in a grid pattern. The light diffusion structure 3 is arranged at the intersection where the first grid line 131 and the second grid line 132 intersect.

[0022] FIG. 3 is a schematic diagram showing a parallelogram formed by line segments connecting a plurality of light diffusion structures according to the embodiment. As shown in FIG. 3, a parallelogram 53 is formed by line segments connecting a first center 31a of a first structure 31, a second center 32a of a second structure 32, a third center 33a of a third structure 33, and a fourth center 34a of a fourth structure 34. The parallelogram 53 is formed by combining a first isosceles triangle 51 and a second isosceles triangle 52. This will be described in detail below.

[0023] The second structure 32 is adjacent to the first structure 31. The third structure 33 is adjacent to the first structure 31 and the second structure 32. The fourth structure 34 is adjacent to the second structure 32 and the third structure 33. With respect to the straight line passing through the second center 32a and the third center 33a, the first structure 31 is located on the opposite side of the fourth structure 34.

[0024] The first isosceles triangle 51 is formed by a first side S1, a second side S2, and a third side S3. The first side S1 is a line segment connecting the first center 31a and the second center 32a. The second side S2 is a line segment connecting the first center 31a and the third center 33a. The third side S3 is a line segment connecting the second center 32a and the third center 33a. The base of the first isosceles triangle 51 is the first side S1. The equal sides of the first isosceles triangle 51 are the second side S2 and the third side S3. Therefore, the length of the second side S2 is equal to the length of the third side S3.

[0025] The second isosceles triangle 52 is formed by the fourth side S4, the fifth side S5, and the third side S3. The fourth side S4 is a line segment connecting the fourth center 34a and the second center 32a. The fifth side S5 is a line segment connecting the fourth center 34a and the third center 33a. The base of the second isosceles triangle 52 is the fifth side S5. The equal sides of the second isosceles triangle 52 are the fourth side S4 and the third side S3. Therefore, the length of the fourth side S4 is equal to the length of the third side S3.

[0026] In this way, by combining the first isosceles triangle 51 and the second isosceles triangle 52, a parallelogram 53 with the first center 31a, the second center 32a, the third center 33a, and the fourth center 34a as vertices is formed.

[0027] Also, the four interior angles θ1, θ2, θ3, and θ4 of the parallelogram 53 are all obtuse or acute angles. Specifically, the interior angle θ1 is the angle formed by the first side S1 and the second side S2. The interior angle θ2 is the angle formed by the fourth side S4 and the fifth side S5. The interior angle θ2 is the opposite angle of the interior angle θ1. The interior angle θ3 is the angle formed by the first side S1 and the fourth side S4. The interior angle θ4 is the angle formed by the second side S2 and the fifth side S5. The interior angle θ4 is the opposite angle of the interior angle θ3. Therefore, the interior angle θ2 is equal to the interior angle θ1, and the interior angle θ4 is equal to the interior angle θ3. In the embodiment, the interior angles θ2 and θ1 are acute angles, and the interior angles θ4 and θ3 are obtuse angles. Also, in the parallelogram 53, the first side S1 and the fifth side S5 are parallel, and the second side S2 and the fourth side S4 are parallel. Note that the parallelogram is not limited to the parallelogram 53 and is variously formed by line segments connecting the centers of four adjacent light diffusing structures 3. For example, in the first region 201, a parallelogram is formed by line segments connecting the centers of the third structure 33, the fourth structure 34, the fifth structure 35, and the sixth structure 36. Also, in the second region 202, a parallelogram is formed by line segments connecting the centers of the seventh structure 37, the eighth structure 38, the second structure 32, and the ninth structure 39, and a parallelogram is also formed by line segments connecting the centers of the second structure 32, the ninth structure 39, the fourth structure 34, and the tenth structure 40.

[0028] FIG. 4 is a schematic diagram showing a first isosceles triangle formed by a line segment connecting a plurality of light diffusion structures according to an embodiment. As described above, the first isosceles triangle 51 is formed by a first side S1, a second side S2, and a third side S3, and the length of the second side S2 is equal to the length of the third side S3.

[0029] Assuming that the apex angle of the first isosceles triangle 51 is angle β and the base angle is angle α, angle β is the angle formed by the second side S2 and the third side S3, and angle α is the angle formed by the first side S1 and the second side S2 or the angle formed by the first side S1 and the third side S3.

[0030] Here, when the midpoint of the first side S1 is the midpoint 43, the straight line L passing through the third center 33a and the midpoint 43 becomes the perpendicular bisector of the first side S1. Therefore, assuming that the line segment connecting the third center 33a and the midpoint 43 is the sixth side S6, and the line segment connecting the first center 31a and the midpoint 43 is the seventh side S7, a right triangle 55 is formed by the second side S2, the sixth side S6, and the seventh side S7. In the right triangle 55, the angle formed by the sixth side S6 and the seventh side S7 is 90 degrees. Also, the angle formed by the second side S2 and the seventh side S7 is angle α, and the angle formed by the second side S2 and the sixth side S6 is angle γ. As described with reference to FIG. 3, angle α is equal to the interior angle θ1.

[0031] Assuming that the length of the seventh side S7 is length L1 and the length of the sixth side S6 is length L2, then tanα = tanθ1 = L2 / L1. Here, assuming that the length of one side of the grid-like square is length p, then L1 = √2p and L2 = 2√2p. Then, tanθ1 = L2 / L1 = 2√2p / √2p = 2. Also, since the interior angle θ1 is equal to the interior angle θ2, the interior angle θ1 = the interior angle θ2 = angle α = arctan(2). Arctan(2) is approximately 63.4 degrees when rounded to the second decimal place. Therefore, the interior angle θ1 and the interior angle θ2 are acute angles.

[0032] Also, for the angle γ, tanγ = L1 / L2 = √2p / 2√2p = 0.5. That is, the angle γ = arctan(0.5). Since the angle β formed by the second side S2 and the third side S3 is twice the angle γ, the angle β = 2×angle γ = 2arctan(0.5). 2arctan(0.5) is approximately 53.1 degrees when rounded to the second decimal place.

[0033] Here, referring to FIG. 3, the interior angles θ3 and θ4 are the sum of the angle β and the angle α. Therefore, the interior angle θ3 = the interior angle θ4 = angle β + angle α = 2arctan(0.5) + arctan(2). 2arctan(0.5) + arctan(2) is approximately 116.5 degrees when rounded to the second decimal place. Therefore, the interior angles θ3 and θ4 are obtuse angles.

[0034] Next, for four adjacent light diffusion structures 3, the average of the distances from each light diffusion structure 3 to the center is obtained. Since the scattered light 121 diffused from the light diffusion structure 3 spreads radially around the light diffusion structure 3, the amount of scattered light 121 decreases as the distance from the light diffusion structure 3 increases. Therefore, for the total light intensity of the scattered light 121 diffused from the four adjacent light diffusion structures 3, the amount of scattered light 121 is the least at the intersection of the diagonals of the quadrilateral with the four light diffusion structures 3 as vertices. For this reason, the smaller the average of the distances between each vertex of the quadrilateral and the intersection of the diagonals, the larger the total amount of scattered light 121 diffused from the four light diffusion structures 3 at the position of the intersection of the diagonals. FIG. 5A is an enlarged schematic view of a parallelogram 53 formed by line segments connecting a plurality of light diffusion structures according to the embodiment. Therefore, specifically, the average of the distances between the vertices of the parallelogram 53 and the intersection of the diagonals is obtained. This will be described in detail below.

[0035] As shown in Fig. 5A, the vertices of the parallelogram 53 are the first center 31a, the second center 32a, the third center 33a, and the fourth center 34a. The intersection of the two diagonals is the center C1. Let the distance between the center C1 and the third center 33a be the distance L3, the distance between the center C1 and the second center 32a be the distance L4, the distance between the center C1 and the first center 31a be the distance L5, and the distance between the center C1 and the fourth center 34a be the distance L6. In this case, the average of the distances between the vertices of the parallelogram 53 and the center C1 is the average of the distances L3, L4, L5, and L6.

[0036] From the properties of the parallelogram 53, the distance L3 = the distance L4. Since the distance L3 + the distance L4 = √10p, the distance L3 = the distance L4 = √10p / 2. Also, from the properties of the parallelogram 53, the distance L5 = the distance L6. Since the distance L5 + the distance L6 = √26p, the distance L5 = the distance L6 = √26p / 2. Therefore, the average of the distances L3, L4, L5, and L6 is (√10p + √26p) / 4. Since the approximate value of (√10p + √26p) / 4 rounded to the second decimal place is 8.3p, the average of the distances between the vertices of the parallelogram 53 and the intersection of the diagonals is approximately 2.1p rounded to the second decimal place.

[0037] Next, a comparative example for Fig. 5A will be described with reference to Fig. 6. Fig. 6 is a schematic diagram showing a comparative example for Fig. 5A and is a diagram forming a square formed by line segments connecting a plurality of light diffusing structures.

[0038] The square 54 shown in Fig. 6 is formed by line segments connecting the center 541a of the structure 541, the center 542a of the structure 542, the center 543a of the structure 543, and the center 544a of the structure 544. The structure 541 corresponds to the second structure 32 shown in Fig. 5A, and the structure 544 corresponds to the fourth structure 34 shown in Fig. 5A. The intersection of the two diagonals in the square 54 is the center C3. Let the distance between the center C3 and the center 543a be the distance L10, the distance between the center C3 and the center 541a be the distance L11, the distance between the center C3 and the center 542a be the distance L12, and the distance between the center C3 and the center 544a be the distance L13.

[0039] From the properties of a square, the distances L10, L11, L12, and L13 are all equal. The distance L10 = √5p. Since the approximate value of √5p rounded to the second decimal place is 2.2p, the average distance between the vertices of the square 54 and the intersection point of the diagonals is approximately 2.2p when rounded to the second decimal place.

[0040] To summarize the above, referring to FIG. 5A, the average distance between the vertices of the parallelogram 53 according to the present embodiment calculated is approximately 2.1p when rounded to the second decimal place. On the other hand, referring to FIG. 6, the average distance between the vertices of the square 54 according to the comparative example calculated is approximately 2.2p when rounded to the second decimal place. Therefore, it is confirmed that the average distance from the center to the light diffusion structure in the present embodiment is smaller (shorter) than that in the comparative example.

[0041] Also, in order to facilitate the design of the arrangement of the light diffusion structures, each light diffusion structure is arranged on the intersection point of each straight line forming a grid. In this case, it is desirable that the shape formed by three adjacent light diffusion structures is as close to an equilateral triangle as possible. For example, it is desirable that the triangles connecting the first center 31a, the second center 32a, and the third center 33a and the triangles connecting the second center 32a, the third center 33a, and the fourth center 34a are as close to an equilateral triangle as possible.

[0042] In the case of an equilateral triangle, when the length of each side is d, the distance between the vertex and the farthest point from each vertex is (2 / d) / {cos(30°)} ≒ 0.58d. Also, when the length of one side of a square is d, the distance between each vertex of the square and the farthest point is (2 / d) / {cos(45°)} ≒ 0.7d.

[0043] Here, consider the triangle connecting the centers 541a, 542a, and 543a in FIG. 6. The farthest point from the centers 541a, 542a, and 543a, which are the vertices of this right isosceles triangle, is the center C3, and the distances from the center C3 to the centers 541a, 542a, and 543a are each substantially 2.2p.

[0044] Also, consider the triangle connecting the first center 31a, the second center 32a, and the third center 33a in FIG. 5A. The length of the first side S1 is 2p√2 ≈ 2.83p. Here, in the case of an equilateral triangle with a side length of 2.83p, the distance between the farthest point from each vertex and each vertex is approximately 2.83p × 0.58 = 1.64p. Although the triangle connecting the first center 31a, the second center 32a, and the third center 33a is not an equilateral triangle, all its interior angles are smaller than 90°. Also, since this triangle has a shape close to an equilateral triangle, the distance between the farthest point from the first center 31a, the second center 32a, and the third center 33a and each vertex is closer to 1.64p than 2.2p. FIG. 5B is a schematic diagram with the distances L7, L8, and L9 added to FIG. 5A. For example, in FIG. 5B, the farthest point from the first center 31a, the second center 32a, and the third center 33a is smaller than the distance L7, which is the distance from the third center 33a to the center C2. The distance L7 = the distance L8 - the distance L9 = 2√2p - the distance L9. The distance L9 = √2p·tanθ. Also, θ = arctan(2√2p / 3√2p) = arctan(2 / 3) ≈ 33.69 degrees. Therefore, the distance L7 = 2√2p - √2p × tanθ ≈ 1.89p. That is, the distance from the scattering structure point according to the embodiment to the farthest point is 1.89p or less. Thus, the distance from the first center 31a, the second center 32a, and the third center 33a to the center C2 is 1.89p even at the farthest distance L7, which is a value smaller than 2.2p.

[0045] From the above, it can be seen that the arrangement of the light diffusing structure in FIGS. 5A and 5B can scatter light more uniformly than the arrangement in FIG. 6.

[0046] Next, the optical filter 82 will be described. FIG. 7A is an enlarged schematic diagram of the cross-section of a collimator and a light guide plate, which is an example of an optical filter. FIG. 7B is an enlarged schematic diagram of the cross-section of a louver and a light guide plate, which is an example of an optical filter.

[0047] The optical filter 82 is an optical element that transmits, toward the optical sensor 81, the component of the light 120 reflected by the object 114 and traveling in the Z direction. 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. Examples of the optical filter 82 include the collimator 82A (collimate aperture) shown in FIG. 7A and the louver 82B shown in FIG. 7B.

[0048] As shown in FIG. 7A, the collimator 82A includes a columnar hole 82A1 (light-guiding portion) extending along the Z direction. The hole 82A1 transmits the light 120 reflected by the 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 diameter d of the light diffusion structure 3.

[0049] As shown in FIG. 7B, 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 114 toward the optical sensor 81. The thickness D2 (the maximum distance along the X direction in the cross section) of the light-guiding portion 82B1 along the X direction is larger than the diameter d of the light diffusion structure 3.

[0050] FIG. 8 is a block diagram showing a configuration example of the detection device according to the embodiment. As shown in FIG. 8, the detection device 100 includes 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 includes an array substrate 811, a plurality of sensor pixels 812 (photodiodes 813) formed on the array substrate 811, gate line drive circuits 814A and 814B, a signal line drive circuit 815A, and a detection control circuit 816. Thus, the optical sensor 81 has photodiodes 813.

[0051] The array substrate 811 is formed with the substrate as the base. Further, each of the plurality of sensor pixels 812 includes a photodiode 813, a plurality of transistors, and various wirings.

[0052] The array substrate 811 has a detection region AA and a peripheral region GA. The detection region AA is a region where a plurality of sensor pixels 812 (a plurality of photodiodes 813) are provided. The peripheral region GA is a region between the outer periphery of the detection region AA and the outer edge of the array substrate 811, and is a region where no plurality of sensor pixels 812 are provided. The gate line drive circuits 814A and 814B, the signal line drive circuit 815A, and the detection control circuit 816 are provided in the peripheral region GA.

[0053] Each of the plurality of sensor pixels 812 is an optical sensor having a photodiode 813 as a sensor element. Each photodiode 813 outputs an electrical signal corresponding to the light irradiated thereon.

[0054] The detection control circuit 816 is a circuit that supplies control signals Sa, Sb, and Sc to the gate line drive circuits 814A and 814B and the signal line drive circuit 815A, respectively, and controls their operations. The detection control circuit 816 includes a signal processing circuit that performs signal processing on the detection signals Vdet from the plurality of photodiodes 813.

[0055] The detection control circuit 816 performs signal processing on the detection signals Vdet from the plurality of photodiodes 813, and outputs a sensor value So based on the detection signals Vdet to the host IC 75. Thereby, the detection device 100 detects information regarding the object 114.

[0056] The light source device 7 includes a light source 71 and a light emitting element control circuit 74.

[0057] As described above, the plurality of light sources 71 are positioned to face the side surface 23 of the light guide plate 2. The plurality of light sources 71 are driven by switching between on (lit state) and off (unlit state) according to a command Sd from the light emitting element control circuit 74.

[0058] The host IC 75 includes a sensor value storage circuit 751, a sensor value calculation circuit 752, a light quantity setting circuit 753, a target value storage circuit 759, a storage circuit 757, and a host PC 758 as a control circuit 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 predetermined arithmetic processing on the sensor value So of the photodiode 813.

[0059] In the light quantity setting mode, the light quantity setting circuit 753 compares the sensor value So detected by the plurality of photodiodes 813 with the preset target sensor value So-t acquired from the target value storage circuit 759, and sets the light quantity for detecting the plurality of light sources 71. The target value storage circuit 759 stores the preset target sensor value So-t.

[0060] The host IC 75 includes a lighting pattern generation circuit 754 and a lighting pattern storage circuit 755 as a control circuit on the light source device 7 side. The lighting pattern storage circuit 755 stores information on the light quantity of each of the plurality of light sources 71 in the light quantity setting mode.

[0061] The lighting pattern generation circuit 754 generates various control signals based on the information on the light quantity in the lighting pattern storage circuit 755.

[0062] In the detection mode, the image generation circuit 756 generates an image of the object 114 based on the sensor value So output from the plurality of photodiodes 813.

[0063] The host IC 75 further includes a memory circuit 757. The memory circuit 757 stores base image data obtained by detecting, with the optical sensor 81, the light irradiated from the light source 71 in a state where the detected object 114 is not mounted on the detected object installation unit 111. Note that the base image data may substantially indicate the same reflectance as that of the detected object installation unit on which nothing is mounted. That is, for example, the base image data may be data detected by placing a subject (e.g., a black plate or a white plate) having a uniform reflectance within the detection surface. Note that the host PC 758 is connected to the image generation circuit 756. The host PC 758 stores, for example, the image data transferred from the image generation circuit 756, and also stores difference image data obtained by subtracting the base image data from the captured image data.

[0064] Next, the propagation of light in the light guide plate will be described. FIG. 9 is a side view schematically showing the propagation of light in the light guide plate. As shown in FIG. 9, the 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 repeatedly undergoing 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 light diffusion structure 3. A part of the scattered light 121, i.e., light 123, is emitted from the second surface 22 of the light guide plate 2 to the detected object 114, reflected by the detected object 114, and irradiated onto the plurality of photodiodes 813 of the optical sensor 81 through the light guide plate 2 and the optical filter 82. In addition to the light 123 emitted to the detected object 114 side, the scattered light 121 scattered by the light diffusion structure 3 also includes light 122 emitted to the optical filter 82 facing the light guide plate 2.

[0065] Next, with reference to FIG. 10 and the like, an example of the detection operation of the detection device will be described. FIG. 10 is a flowchart showing an example of the detection operation of the detection device according to the embodiment.

[0066] First, the light source device 7 turns on the light source 71 based on a control signal from the lighting pattern generation circuit 754 (see FIG. 8) (step S101).

[0067] Next, base image data is generated by detecting the light irradiated from the light source 71 with the optical sensor 81 in a state where the detected object 114 is not mounted on the detected object installation unit 111 (step S102). The base image data is stored in the storage circuit 757 (see FIG. 8).

[0068] 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, the captured image data obtained by detecting with the optical sensor 81 in a state where the detected object 114 is mounted on the detected object installation unit 111 is acquired, and from the difference between the base image data and the captured image data, differential image data indicating the detection result in a state where the detected object 114 is mounted on the detected object installation unit 111 is acquired. The differential image data is calculated by the image generation circuit 756 (see FIG. 8). Then, the differential image data is transferred to the host PC 758 and stored in the host PC 758 (step S104).

[0069] As described above, the detection device 100 according to the embodiment includes a light guide plate 2, a plurality of light diffusion structures 3, an optical sensor 81 including a plurality of photodiodes 813 (light detection elements) arranged in a planar shape, and a light source 71. When viewed from the Z direction, the plurality of light diffusion structures 3 include a first structure 31, a second structure 32, a third structure 33, and a fourth structure 34. A first isosceles triangle 51 is formed by a first side S1, a second side S2, and a third side S3. A second isosceles triangle 52 is formed by a fourth side S4, a fifth side S5, and the third side S3. A parallelogram 53 having the first center 31a, the second center 32a, the third center 33a, and the fourth center 34a as vertices is formed. In the parallelogram 53, the first side S1 and the fifth side S5 are parallel and the second side S2 and the fourth side S4 are parallel, and all four interior angles of the parallelogram 53 are obtuse or acute angles.

[0070] As described above, in the biosensor of Patent Document 1, when the light transmittance of the culture medium in the culture vessel is low, it may be difficult to detect the detected object (microorganism), so a detection device with higher detection accuracy is required.

[0071] Here, in the detection device 100 of the present embodiment, a light source 71 is provided on the side of the light guide plate 2, a plurality of light diffusion structures 3 are provided on the first surface 21 of the light guide plate 2, and the plurality of light diffusion structures 3 are arranged so as to be located at the vertices of a parallelogram 53.

[0072] As described above, regarding the total light intensity of the scattered light 121 diffused from four adjacent light diffusion structures 3, the amount of scattered light 121 is the least at the intersection of the diagonals of the quadrilateral with the four light diffusion structures 3 as vertices. Therefore, the smaller the average of the distances between each vertex of the quadrilateral and the intersection of the diagonals, the larger the total amount of scattered light 121 diffused from the four light diffusion structures 3 at the position of the intersection of the diagonals.

[0073] Therefore, as verified with reference to FIG. 5A, the average of the distances between the vertices of the parallelogram 53 according to the present embodiment and the intersection of the diagonals (center C1) is 2.1p. Also, regarding the arrangement mode of the light diffusion structures 3, when a square 54 is used as a comparative example for the parallelogram 53 of the detection device 100 of the present embodiment, as verified with reference to FIG. 6, the average of the distances between the vertices of the square 54 and the intersection of the diagonals (center C3) is 2.2p. Thus, the parallelogram 53 according to the present embodiment has a smaller average of the distances between each vertex of the quadrilateral and the intersection of the diagonals than the square 54.

[0074] Also, as described with reference to FIG. 5B, the distances from the first center 31a, the second center 32a, and the third center 33a to the center C2 are 1.89p even at the farthest distance L7, which is a value smaller than 2.2p.

[0075] From the above, according to the present embodiment, since the total amount of light of the scattered light 121 diffused from the light diffusion structure 3 becomes larger, it is possible to provide a detection device in which the detection accuracy of the object to be detected is improved.

[0076] In addition, the interior angles θ1 and θ2 of the parallelogram 53 are each arctan(2), and the interior angles θ3 and θ4 are each the sum of 2arctan(0.5) and arctan(2).

[0077] Since the interior angles θ1 and θ2 are approximately 63.4 degrees, they are acute angles. Since the interior angles θ3 and θ4 are approximately 116.5 degrees, they are obtuse angles. Therefore, the quadrilateral formed by the line segments connecting the first structure 31, the second structure 32, the third structure 33, and the fourth structure 34 is not a square or a rectangle but a parallelogram. Thus, as described above, the average of the distances between each vertex of the quadrilateral and the intersection point of the diagonals becomes smaller, and at the position of the intersection point of the diagonals, the total amount of scattered light 121 diffused from the four adjacent light diffusion structures 3 becomes larger.

[0078] A light filter 82 is provided between the light guide plate 2 and the optical sensor 81. The light filter 82 causes more of the light 120 reflected by the object to be detected 114 and transmitted through the light guide plate 2 to travel toward the photodiode 813. Thereby, the detection accuracy of the object to be detected 114 can be further improved.

[0079] It includes a detection object installation part 111 that is arranged to overlap the light guide plate 2 on the Z2 side and on which the detection object 114 is installed. For this reason, when the detection object 114 is a microorganism such as bacteria or a sample containing microorganisms, by using a container such as a petri dish and a culture medium as the detection object installation part 111, the detection work of the detection object 114 can be performed more smoothly.

[0080] Since the optical sensor 81 has a plurality of photodiodes 813, it is possible to improve the image quality of the captured image.

Explanation of Reference Numerals

[0081] 2 Light guide plate 3 Light diffusion structure 7 Light source device 31 First structure 32 Second structure 33 Third structure 34 Fourth structure 51 First isosceles triangle 52 Second isosceles triangle 53 Parallelogram 71 Light source 81 Optical sensor 82 Optical filter 100 Detection device 111 Object installation part 114 Object 120 Light 121 Scattered light 813 Photodiode (light detection element) FL Front light θ1, θ2, θ3, θ4 Interior angles

Claims

1. A light guide plate having translucency, A plurality of light diffusion structures provided on one side surface of the light guide plate in a first direction, An optical sensor including a plurality of light detection elements arranged so as to overlap and be arranged in a planar manner on one side of the light guide plate in the first direction, A light source arranged adjacent to the light guide plate in a second direction intersecting the first direction and irradiating light onto the side surface of the light guide plate, and comprising: When viewed from the first direction, The plurality of light diffusion structures include a first structure, a second structure adjacent to the first structure, a third structure adjacent to the first structure and the second structure, and a fourth structure adjacent to the second structure and the third structure, and the first structure is located on the opposite side of the fourth structure with respect to a straight line passing through the second structure and the third structure, A first side connecting a first center of the first structure and a second center of the second structure, a second side connecting the first center and a third center of the third structure, and a third side connecting the second center and the third center form a first isosceles triangle having the first side as a base and the second side and the third side as equal sides, A fourth side connecting a fourth center of the fourth structure and the second center, a fifth side connecting the fourth center and the third center, and the third side form a second isosceles triangle having the fifth side as a base and the third side and the fourth side as equal sides, The first isosceles triangle and the second isosceles triangle form a parallelogram having the first center, the second center, the third center, and the fourth center as vertices, In the parallelogram, the first side and the fifth side are parallel and the second side and the fourth side are parallel, All four interior angles of the parallelogram are obtuse or acute angles, A detection device.

2. The four interior angles of the parallelogram are interior angle θ1, interior angle θ2 which is the opposite angle of the interior angle θ1, interior angle θ3, and interior angle θ4 which is the opposite angle of the interior angle θ3. The interior angle θ1 is the angle formed by the first side and the second side. The interior angle θ2 is the angle formed by the fourth side and the fifth side. The interior angle θ3 is the angle formed by the first side and the fourth side. The interior angle θ4 is the angle formed by the second side and the fifth side. The interior angle θ1 and the interior angle θ2 are each arctan(2). The interior angle θ3 and the interior angle θ4 are each the sum of 2arctan(0.5) and arctan(2). The detection device according to claim 1.

3. An optical filter is provided between the light guide plate and the optical sensor. The detection device according to claim 1.

4. It includes a detected object installation part that is arranged to overlap on the other side of the first direction with respect to the light guide plate and on which the detected object is installed. The detection device according to claim 3.

5. The optical sensor has a plurality of photodiodes. The detection device according to any one of claims 1 to 4.

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