Toilet seat device

Abstract

To provide a sensor unit capable of attaining size reduction while suppressing reception of reflectance reflected by a transmission window, by light-receiving elements, and a toilet seat device.SOLUTION: The sensor unit according to an embodiment comprises: a light-emitting element which emits light toward an object; two light-receiving elements which receive light from the object; and a transmission window disposed between the light-emitting element and the object and transmitting the light from the light-emitting element. The two light-receiving elements are arranged so as to be positioned concentrically with respect to the light-emitting element and to be positioned in a range less than 180 degree about the light-emitting element.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The disclosed embodiments relate to a sensor unit and a toilet seat apparatus. [Background technology]

[0002] Conventionally, a sensor has been proposed that measures blood flow conditions and the like by irradiating light such as laser light toward the human body and receiving and analyzing scattered light reflected by the human body (see, for example, Patent Document 1). Note that the sensor according to the conventional technology is configured to include a light-emitting element that emits light and two light-receiving elements that receive the light. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5785267 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when the above-mentioned sensor is installed, for example, on a toilet seat, a transmission window that transmits light from the light-emitting element may be placed between the sensor and the human body (user) to protect the sensor. However, when a transmission window is placed, the light-receiving element may receive reflected light reflected by the transmission window in addition to the scattered light reflected by the user. Since such reflected light is not light reflected by the user, there is a risk that it may become noise in the process of measuring the blood flow state. In addition, in the sensor unit equipped with the above-mentioned sensor, it is desirable to reduce the size due to storage space restrictions and design considerations.

[0005] An object of one aspect of the embodiment is to provide a sensor unit and a toilet seat apparatus that can be made smaller while suppressing reception of light reflected by a transmission window by a light receiving element. [Means for solving the problem]

[0006] A sensor unit according to one aspect of the embodiment includes a light-emitting element that emits light toward an object, two light-receiving elements that receive the light from the object, and a transparent window that is disposed between the light-emitting element and the object and transmits the light from the light-emitting element. The two light-receiving elements are disposed concentrically with the light-emitting element and within a range of less than 180 degrees from the light-emitting element.

[0007] In this way, the two light receiving elements are arranged so as to be positioned on a concentric circle of the light emitting element, so that the scattered light can be received evenly between the two light receiving elements, in other words, the bias of the received scattered light can be suppressed. Therefore, for example, in the case of differential amplification of signals indicating the scattered light received by the two light receiving elements, if the scattered light is biased, there is a risk of a decrease in the measurement accuracy of the blood flow state, but by arranging the two light receiving elements as described above, it is possible to suppress the decrease in measurement accuracy caused by the bias of the scattered light.

[0008] In addition, since the two light receiving elements are positioned so that they are located within a range of less than 180 degrees centered on the light emitting element, the range in which the two light receiving elements are positioned can be made relatively small, thereby making it possible to miniaturize the sensor unit.

[0009] Moreover, the two light receiving elements are disposed apart from each other.

[0010] In this way, by arranging the two light receiving elements at a distance from each other, it is possible to suppress the influence of reflected light (noise) as much as possible. That is, for example, if the transparent window has an angle variation or the like and is tilted, the reflected light may slightly hit the light receiving element. Even in such a case, since the two light receiving elements are arranged at a distance from each other, it is possible to make it difficult for the two light receiving elements to be simultaneously influenced by the reflected light, and therefore it is possible to suppress the influence of reflected light (noise) as much as possible.

[0011] The two light receiving elements are formed to have a quadrangular shape when viewed from above, and are arranged so that one side is parallel to a tangent to a concentric circle relative to the light emitting element.

[0012] In this way, since the light receiving element is arranged so that one side is parallel to the tangent of the concentric circle with respect to the light emitting element, it is possible to make it difficult for reflected light to be incident on, for example, the corner of the light receiving element, which means that it is possible to effectively prevent the light receiving element from receiving reflected light.

[0013] The light emitting element and the two light receiving elements are disposed on the same plane, and the transmission window is provided so as to be inclined with respect to a straight line connecting the light emitting element and the two light receiving elements.

[0014] This makes it possible to suppress the light receiving element from receiving the reflected light reflected by the transmission window. More specifically, light emitted from the light emitting element is reflected by the transmission window. Since the transmission window is inclined as described above, the reflected light reflected by this transmission window strikes, for example, a position on the sensor substrate different from that of the light receiving element. In other words, the inclination of the transmission window makes it difficult for the reflected light reflected by the transmission window to strike the light receiving element. This makes it possible to suppress the light receiving element from receiving the reflected light reflected by the transmission window. More specifically, it is possible to suppress the light receiving element from receiving reflected light that becomes noise in the process of measuring, for example, the blood flow state.

[0015] Moreover, the two light receiving elements are each arranged such that the center of the light receiving element is concentric with the light emitting element.

[0016] In this way, the two light receiving elements are arranged so that the center of each light receiving element is concentric with the light emitting element, so that the scattered light can be received evenly between the two light receiving elements, in other words, the bias of the received scattered light can be further suppressed. Therefore, for example, in the case of differential amplification of signals indicating the scattered light received by the two light receiving elements, if the scattered light is biased, there is a risk of a decrease in the measurement accuracy of the blood circulation state, but by arranging the two light receiving elements as described above, it is possible to further suppress the decrease in measurement accuracy caused by the bias of the scattered light.

[0017] The toilet seat device includes a sensor unit and a toilet seat provided with the sensor unit. The sensor unit includes a light-emitting element that emits light toward an object, two light-receiving elements that receive light from the object, and a transparent window that is disposed between the light-emitting element and the object and transmits light from the light-emitting element. The two light-receiving elements are disposed so as to be concentric with the light-emitting element and within a range of less than 180 degrees from the light-emitting element as the center.

[0018] This makes it possible to reduce the size of the sensor unit provided on the toilet seat while preventing the light receiving element from receiving light reflected by the transmission window. Effect of the Invention

[0019] According to one aspect of the embodiment, it is possible to achieve miniaturization while suppressing reception of light reflected by the transmission window by the light receiving element. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a perspective view of a flush toilet apparatus equipped with a toilet seat apparatus according to a first embodiment. [Diagram 2] FIG. 2 is a block diagram showing an example of the configuration of the measurement system. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4]FIG. 4 is a side cross-sectional view showing the light emitting element, the light receiving element, and the transmission window as viewed from the side. [Diagram 5] FIG. 5 is a side cross-sectional view showing the light emitting element, the light receiving element, and the transmission window as viewed from the side. [Figure 6] FIG. 6 is a top view showing a light emitting element and a light receiving element. [Figure 7] FIG. 7 is a top view showing a light emitting element and a light receiving element in a modification of the first embodiment. [Figure 8] FIG. 8 is a side cross-sectional view showing a light emitting element, a light receiving element, and a transmission window in a side view in the second embodiment. [Figure 9] FIG. 9 is a side cross-sectional view showing a light emitting element, a light receiving element, and a transmission window in a side view in the second embodiment. [Figure 10] FIG. 10 is a top view showing a light emitting element and a light receiving element in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, embodiments of a sensor unit and a toilet seat apparatus disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below.

[0022] (First embodiment) A toilet seat device including a sensor unit according to a first embodiment will be described with reference to Fig. 1. Fig. 1 is a perspective view of a flush toilet device including the toilet seat device according to the first embodiment. Fig. 1 and Fig. 3 onwards are all schematic diagrams.

[0023] For ease of explanation, FIG. 1 and other figures show a three-dimensional Cartesian coordinate system in which mutually orthogonal X-axis, Y-axis, and Z-axis directions are defined, and the positive Z-axis direction is the vertically upward direction. In the following explanation, the positive X-axis direction may be referred to as the "left", the negative X-axis direction as the "right", the positive Y-axis direction as the "rear", and the negative Y-axis direction as the "front". In other words, the directions as seen by a user sitting on the toilet seat 30 described later may be referred to as the "left", "right", "rear", and "front". For this reason, in the following explanation, the X-axis direction may be referred to as the left-right direction, the Y-axis direction as the front-rear direction, and the Z-axis direction as the up-down direction (vertical direction).

[0024] As shown in FIG. 1, the flush toilet device 1 comprises a flush toilet 10 and a toilet seat device 20. The flush toilet 10 comprises a bowl portion 11. The bowl portion 11 is formed in a bowl shape capable of receiving waste. The bowl portion 11 is flushed by discharging flush water, and the flush water that has cleaned the bowl portion 11 is discharged through a drainage pipe (not shown). The flush toilet 10 is made of ceramic, for example. However, the flush toilet 10 is not limited to being made of ceramic, and could be made of resin, for example, or a combination of ceramic and resin.

[0025] The toilet seat device 20 is attached to the top of the flush toilet 10, and comprises a toilet seat 30, a toilet lid 36, a functional section 38, and a sensor unit 40. The toilet seat device 20 may be attached to the flush toilet 10 in a detachable manner, or may be attached so as to be integrated with the flush toilet 10.

[0026] The toilet seat 30 is formed in an annular shape with an opening in the center, and is positioned along the rim portion 12 in a position that overlaps with the opening of the flush toilet 10. The toilet seat 30 is made of, for example, resin, and has a seating surface 31 on which a user sits. The seating surface 31 supports the buttocks, thighs, etc. of a seated user. The toilet seat 30 is also formed hollow, and a sensor unit 40 and the like are provided inside.

[0027] The toilet lid 36 is attached to the toilet seat 30 so as to be openable and closable. The functional part 38 houses, for example, a nozzle device and sprays wash water from the nozzle device onto the user's body to wash the private parts. The toilet seat device 20 may be configured without the toilet lid 36 or functional part 38 described above.

[0028] The sensor unit 40 includes a sensor 51 (see FIG. 2) capable of measuring various conditions related to a user who uses the flush toilet device 1. For example, the sensor 51 is a sensor capable of measuring the blood flow condition of a user seated on the toilet seat 30. Such a sensor 51 can be an optical biosensor (for example, a blood flow sensor using laser light). Here, a measurement system including the sensor 51 will be described with reference to FIG. 2. FIG. 2 is a block diagram showing an example configuration of the measurement system.

[0029] 2, the measurement system 100 includes the above-mentioned sensor 51, a control device 110, and a display device 120. The sensor 51 includes a light-emitting element 52 and two light-receiving elements.

[0030] The light-emitting element 52 emits, for example, laser light. Specifically, the light-emitting element 52 irradiates, for example, laser light to a user seated on the toilet seat 30. More specifically, when the user is seated on the toilet seat 30, the light-emitting element 52 irradiates laser light toward a measurement site on the user's buttocks or thighs. Note that the light-emitting element 52 is not limited to laser light, and may be configured to emit other types of light, such as infrared light or visible light. Also, the user to whom light is emitted (irradiated) (more precisely, the measurement site of the user) is one example of a target object.

[0031] The two light receiving elements 53 receive light from the user (more precisely, the measurement site of the user). Of the two light receiving elements 53, one may be referred to as the "first light receiving element 53a" and the other as the "second light receiving element 53b." Furthermore, when the first and second light receiving elements 53a and 53b are described without any particular distinction, they will be referred to as the "light receiving element 53" or the "two light receiving elements 53."

[0032] In detail, the light (irradiated light; laser light) irradiated from the light-emitting element 52 is reflected by the blood vessels (blood flow) of the user, and the two light-receiving elements 53 receive the reflected light (scattered light). The sensor 51 outputs a signal related to the irradiated light or scattered light, such as the frequency of the irradiated light or scattered light, to the control device 110.

[0033] The control device 110 includes a control unit 111, a storage unit 112, and a communication unit 113. The control device 110 is housed in, for example, the functional unit 38 (see FIG. 1) of the toilet seat device 20, but is not limited to this.

[0034] The control unit 111 is realized by, for example, a central processing unit (CPU) or a micro processing unit (MPU) executing a program stored in the storage unit 112 using a random access memory (RAM) as a working area. The control unit 111 can also be realized by hardware such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The storage unit 112 has a volatile memory and a non-volatile memory, and is realized by, for example, a semiconductor memory element such as a RAM or a flash memory.

[0035] The control unit 111 measures the state of blood flow, such as the pulse rate, pulse fluctuation, and blood flow rate of the user, based on the signal output from the sensor 51. For example, the control unit 111 performs a process of detecting a change in the flow rate of red blood cells flowing through a blood vessel using a laser beam. The control unit 111 performs a process of detecting a frequency at which a Doppler shift occurs due to red blood cells flowing through a blood vessel.

[0036] Specifically, the control unit 111 amplifies (in other words, differentially amplifies) the difference between the electrical signal indicating the scattered light received by the first light receiving element 53a and the electrical signal indicating the scattered light received by the second light receiving element 53b. The above-mentioned differential amplification may be performed by a differential amplifier circuit. Then, the control unit 111 performs a process of detecting a change in the flow rate of red blood cells and a process of detecting a frequency at which a Doppler shift occurs based on the amplified signal. That is, the control unit 111 performs a process of analyzing the light emitted from the light emitting element 52 and the signal related to the scattered light received by each of the two light receiving elements 53 to measure the blood flow state. The information indicating the measured blood flow state is not limited to the above-mentioned pulse rate, pulse fluctuation, blood flow rate, etc. of the user, but may be any information indicating the state of the user's blood flow, in other words, any biological information of the user.

[0037] The communication unit 113 transmits and receives information to and from the display device 120. The control device 110 and the display device 120 may be connected by wireless communication or by wired communication. The control unit 111 outputs information indicating the measured blood flow state to the display device 120 via the communication unit 113.

[0038] The display device 120 displays information indicating the measured blood flow state. This allows the user to confirm (understand) their own blood flow state. Note that the display device 120 may be the display section of a remote control that outputs operation instructions for the toilet seat device 20 and flush instructions for the flush toilet 10, or it may be the display section of a mobile terminal used by the user, but these are merely examples and are not limiting.

[0039] In addition, the sensor 51 is not limited to the sensor that measures the blood flow condition of the user described above, but may include other types of sensors, such as a load sensor that measures the user's weight, or a body fat sensor that measures the user's body fat percentage.

[0040] Returning to the description of Fig. 1, an opening 32 is formed in a seating surface 31 of a toilet seat 30. A sensor unit 40 according to the embodiment is fixed to the toilet seat 30 so that a portion of the sensor unit 40 is exposed from the opening 32.

[0041] Incidentally, when the above-mentioned sensor 51 is provided on the toilet seat 30, a transparent window 64 (see FIG. 3) that transmits light from the light-emitting element 52 is provided between the sensor 51 and the user to protect the sensor 51 from dirt, impact, and the like. However, when the transparent window 64 is provided, the light-receiving element 53 may receive reflected light reflected by the transparent window 64 in addition to the scattered light reflected by the user. Such reflected light is not reflected by the user and is not light that indicates the state of blood flow, so there is a risk that it may become noise in the process of measuring the state of blood flow. In addition, in the sensor unit 40 equipped with the sensor 51, it has been desired to make it smaller in size due to storage space restrictions and design considerations.

[0042] Therefore, in this embodiment, it is possible to suppress the light reflected by the transmission window 64 from being received by the light receiving element 53, while achieving miniaturization.

[0043] The sensor unit 40 and other components according to this embodiment will be described in detail with reference to Fig. 3. Fig. 3 is a cross-sectional view taken along line III-III in Fig. 1. In Fig. 3, a user A seated on the seating surface 31 of the toilet seat 30 is indicated by a two-dot chain line, and the measurement site of the user A is indicated by the symbol "A1".

[0044] As shown in FIG. 3, the sensor unit 40 includes a sensor 51, a sensor board 55, and a sensor case 60, and is fixed to the toilet seat 30.

[0045] 3, the sensor 51 is mounted on a sensor substrate 55. For example, the sensor substrate 55 is made of resin, and the upper surface of the sensor substrate 55 is a main surface 55a. The sensor 51 is mounted near the center of the main surface 55a of the sensor substrate 55.

[0046] As described above, the sensor 51 includes the light-emitting element 52 and two light-receiving elements 53 (one not visible in FIG. 3). When the user A is seated on the toilet seat 30, the light-emitting element 52 emits light (e.g., laser light) toward the measurement site A1 on the buttocks or thigh of the user A (see arrow B1). The light-emitting element 52 can also be said to be a light-emitting unit or an irradiating unit.

[0047] The light receiving element 53 receives light from the user A (see arrow B2). More specifically, the light receiving element 53 receives scattered light that is reflected at the measurement site A1 of the user A. The light receiving element 53 can also be said to be a light receiving section. The sensor 51 may be a single member in which the light emitting element 52 and the two light receiving elements 53 are integrated into a unit.

[0048] The positions at which the light emitting element 52 and the two light receiving elements 53 are arranged will be described later with reference to FIGS.

[0049] The sensor case 60 houses the sensor board 55 and the like. The sensor case 60 is made of resin, but is not limited to this.

[0050] The sensor case 60 includes a main body 61, a protruding portion 62, and a bottom surface portion 63. The main body 61 is formed, for example, in the shape of a hollow rectangular parallelepiped. The lower surface side of the main body 61 is opened and open.

[0051] The protruding portion 62 is formed so as to protrude upward from the upper portion of the main body portion 61. The protruding portion 62 is formed, for example, so as to have a hollow cylindrical shape. A transmission window (sensor window) 64 is provided on the upper portion of the protruding portion 62.

[0052] The sensor case 60 is fixed to the toilet seat 30 with the transmission window 64 exposed from the opening 32 of the toilet seat 30. The light emitting element 52 and the light receiving element 53 are disposed below the transmission window 64. That is, the transmission window 64 is disposed between the light emitting element 52 and the light receiving element 53 and the measurement site A1 of the user A. The transmission window 64 transmits light from the light emitting element 52 (see arrow B1). The transmission window 64 also transmits scattered light reflected at the measurement site A1 of the user A (see arrow B2). That is, the light emitting element 52 of the sensor 51 irradiates light to the user A through the transmission window 64, and the light receiving element 53 receives the scattered light reflected at the blood vessels of the user A through the transmission window 64.

[0053] The bottom surface portion 63 is formed, for example, in a flat plate shape. The bottom surface portion 63 is attached to the main body portion 61 from the opening side of the lower surface of the main body portion 61, and fixed to the main body portion 61. At this time, the sensor board 55 is disposed and fixed between the main body portion 61 and the bottom surface portion 63.

[0054] Next, the configurations of the light emitting element 52, the two light receiving elements 53, and the transmission window 64 according to this embodiment will be described with reference to FIGS. 4 to 6. FIG. 4 is a side cross-sectional view showing the light emitting element 52, the light receiving element 53, and the transmission window 64 in a side view (more specifically, in a Y-axis direction view from the Y-axis direction). FIG. 5 is a side cross-sectional view showing the light emitting element 52, the light receiving element 53, and the transmission window 64 in a side view (more specifically, in an X-axis direction view from the X-axis direction). FIG. 6 is a top view (plan view) showing the light emitting element 52 and the light receiving element 53 in a top view (plan view). For ease of understanding, the transmission window 64 is omitted in FIG. 6. Also, in FIG. 6, the range on the sensor substrate 55 where the scattered light reflected by the blood vessels of the user A hits is indicated by the symbol E.

[0055] 4 to 6, the light emitting element 52 and the two light receiving elements 53 are disposed on the same plane. Specifically, the light emitting element 52 and the two light receiving elements 53 are disposed on the main surface 55a of the same sensor substrate 55.

[0056] As shown in FIG. 6, the two light receiving elements 53 are arranged so as to be located on a concentric circle with respect to the light emitting element 52. Specifically, the two light receiving elements 53 are arranged so that the center of the light receiving element 53 is on a concentric circle with respect to the light emitting element 52. More specifically, the first light receiving element 53a is arranged so that the center 53ax is on a concentric circle with respect to the light emitting element 52, and the second light receiving element 53b is arranged so that the center 53bx is on a concentric circle with respect to the light emitting element 52. This concentric circle is a circle centered on the center 52x of the light emitting element 52, and an example of a concentric circle is indicated by the symbol D. In this way, since the two light receiving elements 53 are located on the concentric circle D with respect to the light emitting element 52, it can be said that the two light receiving elements 53 are arranged so as to be at the same distance from the light emitting element 52.

[0057] The two light receiving elements 53 are arranged so as to be located within a range of less than 180 degrees centered on the light emitting element 52. In other words, the two light receiving elements 53 are arranged so as to be located within a range of less than 180 degrees in a circumferential range centered on the light emitting element 52. Specifically, in a top view, 180 degrees (α) centered on the light emitting element 52 is indicated by a virtual straight line L passing through the center portion 52x of the light emitting element 52, and the two light receiving elements 53 are arranged so as to be located within the range La of less than 180 degrees (α).

[0058] More specifically, in the range La less than 180 degrees (α), the two light receiving elements 53 are arranged such that the angle α1 between the line connecting the first light receiving element 53a and the light emitting element 52 and the line connecting the second light receiving element 53b and the light emitting element 52 is, for example, 60 degrees to 90 degrees. In detail, in the range La less than 180 degrees (α), the two light receiving elements 53 are arranged such that the angle α1 between the virtual line connecting the center 53ax of the first light receiving element 53a and the center 52x of the light emitting element 52 and the virtual line connecting the center 53bx of the second light receiving element 53b and the center 52x of the light emitting element 52 is, for example, 60 degrees to 90 degrees. Note that, although the angle α1 is shown by a specific numerical value in the above, this is merely an example and is not limited, and it can be set to any value less than 180 degrees.

[0059] The two light receiving elements 53 receive scattered light reflected by the blood vessels of the user A, and are therefore disposed within a range E where the scattered light strikes.

[0060] The two light receiving elements 53 according to this embodiment are disposed at the above-mentioned positions, so that the light receiving elements 53 can be prevented from receiving the light reflected by the transmission window 64, and can be made compact.

[0061] That is, as shown in Fig. 4, light emitted from the light-emitting element 52 (see arrow B3) is reflected by the transmission window 64 (see arrow B4). The reflected light reflected by this transmission window 64 hits the light-emitting element 52 and the periphery of the light-emitting element 52 on the sensor substrate 55. Note that in Figs. 4 and 6, the area on the sensor substrate 55 where the reflected light hits is indicated by the symbol C. Also, in Fig. 4, refraction of light at the transmission window 64 is omitted for the sake of simplicity.

[0062] Since the two light receiving elements 53 are disposed in an area outside the concentric area C of the light emitting element 52 with respect to the area C where such reflected light hits, the reflected light reflected by the transmission window 64 does not hit the light receiving element 53 or is unlikely to hit the light receiving element 53. That is, it is possible to prevent the light receiving element 53 from receiving the reflected light reflected by the transmission window 64. In more detail, it is possible to prevent the light receiving element 53 from receiving the reflected light that becomes noise in the process of measuring the blood flow state, for example.

[0063] Furthermore, by arranging the two light receiving elements 53 so as to be positioned on a concentric circle of the light emitting element 52, the scattered light can be received evenly between the two light receiving elements 53, in other words, bias in the received scattered light can be suppressed. Therefore, for example, in the case of differentially amplifying the signal indicating the scattered light received by the two light receiving elements 53, if bias occurs in the scattered light, there is a risk of a decrease in the measurement accuracy of the blood flow state, but by arranging the two light receiving elements 53 as described above, it is possible to suppress a decrease in measurement accuracy caused by bias in the scattered light.

[0064] In addition, since the two light receiving elements 53 are positioned so as to be located within a range La of less than 180 degrees centered on the light emitting element 52, the range in which the two light receiving elements 53 are positioned can be made relatively small, thereby making it possible to miniaturize the sensor unit 40.

[0065] The two light receiving elements 53 are disposed spaced apart from each other. More specifically, the first light receiving element 53a and the second light receiving element 53b are disposed spaced apart by a predetermined distance F. The predetermined distance F can be set to any value.

[0066] In this way, by arranging the two light receiving elements 53 at a distance from each other, it is possible to suppress the influence of reflected light (noise) as much as possible. That is, for example, when the transparent window 64 is tilted due to an angle variation or the like occurring in the transparent window 64, the reflected light may slightly hit the light receiving element 53. Even in such a case, since the two light receiving elements 53 are arranged at a distance from each other, it is possible to make it difficult for the two light receiving elements 53 to be simultaneously influenced by the reflected light, and therefore it is possible to suppress the influence of the reflected light (noise) as much as possible.

[0067] 6, the two light receiving elements 53 are formed to have a quadrangular shape in a top view. The light receiving elements 53 are arranged such that one side is parallel to a tangent D1 of the concentric circle D for the light emitting element 52. Specifically, the first light receiving element 53a is arranged such that one side 53ay is parallel to a tangent D1 of the concentric circle D for the light emitting element 52. Similarly, the second light receiving element 53b is arranged such that one side 53by is parallel to a tangent D1 of the concentric circle D for the light emitting element 52. Note that the one side 53ay, 53by here is, for example, at least one of the four sides of the light receiving element 53, the side facing the light emitting element 52, and the side located opposite to the facing side.

[0068] In this way, since the light receiving element 53 is arranged such that one side is parallel to the tangent line D1 of the concentric circle D with respect to the light emitting element 52, it is possible to make it difficult for reflected light to be incident on, for example, a corner of the light receiving element 53. In other words, it is possible to effectively prevent the light receiving element 53 from receiving reflected light.

[0069] As described above, the sensor unit 40 according to the first embodiment includes the light-emitting element 52 that emits light toward the target (user A), two light-receiving elements 53 that receive the light from the target, and a transmission window 64 that is disposed between the light-emitting element 52 and the target and transmits the light from the light-emitting element 52. The two light-receiving elements 53 are disposed so as to be located on a concentric circle D with respect to the light-emitting element 52 and within a range La of less than 180 degrees centered on the light-emitting element 52. This makes it possible to achieve a compact size while preventing the light-receiving element 53 from receiving the light reflected by the transmission window 64.

[0070] (Modification of the first embodiment) Next, a modified example of the first embodiment will be described with reference to Fig. 7. Fig. 7 is a top view similar to Fig. 6, showing a light emitting element 52 and a light receiving element 53 in a top view in a modified example of the first embodiment. Note that, hereinafter, the same components as those in the first embodiment are given the same reference numerals, and descriptions thereof may be omitted.

[0071] 7, in the modification of the first embodiment, the light receiving element 53 having a rectangular shape when viewed from above is disposed so that its four sides intersect with a tangent line D1 of the concentric circle D for the light emitting element 52. Specifically, the first light receiving element 53a is disposed so that its four sides 53az intersect with a tangent line D1 of the concentric circle D for the light emitting element 52. Similarly, the second light receiving element 53b is disposed so that its four sides 53bz intersect with a tangent line D1 of the concentric circle D for the light emitting element 52.

[0072] In this way, even if the light receiving element 53 is positioned so that its four sides intersect with the tangent D1 of the concentric circle D relative to the light emitting element 52, the light receiving element 53 can be prevented from receiving reflected light, as in the first embodiment.

[0073] Second embodiment Next, the sensor unit 40 and the like according to the second embodiment will be described with reference to Figs. 8 to 10. Fig. 8 is a side cross-sectional view showing the light-emitting element 52, the light-receiving element 53, and the transmission window 64 in a side view (more specifically, in a Y-axis direction view from the Y-axis direction). Fig. 9 is a side cross-sectional view showing the light-emitting element 52, the light-receiving element 53, and the transmission window 64 in a side view (more specifically, in an X-axis direction view from the X-axis direction). Fig. 10 is a top view showing the light-emitting element 52 and the light-receiving element 53 in a top view.

[0074] For ease of understanding, as shown in FIG. 10, the light-emitting element 52 and the two light-receiving elements 53 are virtually connected to each other by straight lines G and H, and the description may be made using the straight lines G and H. In detail, in top view, a straight line connecting the center 52x of the light-emitting element 52 and the center 53ax of the first light-receiving element 53a is described as a "first straight line Ga." In addition, in top view, a straight line connecting the center 52x of the light-emitting element 52 and the center 53bx of the second light-receiving element 53b is described as a "second straight line Gb." In addition, in top view, a straight line connecting the two light-emitting elements 52, in other words, a straight line connecting the center 53ax of the first light-receiving element 53a and the center 53bx of the second light-receiving element 53b is described as an "inter-light-receiving element straight line H."

[0075] 10, the light-emitting element 52 and the two light-receiving elements 53 are arranged such that a straight line G connecting the light-emitting element 52 and the two light-receiving elements 53, respectively, and a straight line H between the light-receiving elements form a triangle in a top view. For example, the light-emitting element 52 and the two light-receiving elements 53 are arranged such that a first straight line Ga and a second straight line Gb have the same length and form an isosceles triangle. In other words, the two light-receiving elements 53 are arranged so as to be located on a concentric circle D with respect to the light-emitting element 52.

[0076] In the second embodiment, for the light-emitting element 52 and two light-receiving elements 53 arranged as described above, the transmission window 64 is provided at an angle so that the light reflected by the transmission window 64 does not hit the light-receiving element 53.

[0077] Specifically, as shown in Fig. 8, the transmission window 64 is provided so as to be inclined with respect to a straight line G that connects the light emitting element 52 and the two light receiving elements. More specifically, the transmission window 64 is provided so as to be inclined at an inclination angle β in a side view with respect to the straight line G (more precisely, a first straight line Ga and a second straight line Gb (see Fig. 10)) that connects the light emitting element 52 and the two light receiving elements. In other words, the transmission window 64 is provided so as to be inclined at an inclination angle β in a side view with respect to the main surface 55a of the sensor substrate 55 including the first straight line Ga and the second straight line Gb.

[0078] In other words, the transparent window 64 has a lower window surface 64a facing the light-emitting element 52 and an upper window surface 64b opposite the window surface 64a, and the window surfaces 64a, 64b are arranged so as to be inclined with respect to the straight line G.

[0079] The transmissive window 64 according to the second embodiment is provided at an incline as described above, and thereby can further prevent the light receiving element 53 from receiving the reflected light reflected by the transmissive window 64. That is, since the transmissive window 64 is provided at an incline as described above, the reflected light reflected by the transmissive window 64 hits a position on the sensor substrate 55 different from the light receiving element 53. In other words, the inclination of the transmissive window 64 prevents the reflected light reflected by the transmissive window 64 from hitting the light receiving element 53, or makes it difficult for the reflected light to hit the light receiving element 53.

[0080] Thus, in this embodiment, the transmission window 64 is provided so as to be inclined with respect to the straight lines G (first straight line Ga, second straight line Gb) connecting the light emitting element 52 and the two light receiving elements 53. This makes it possible to prevent the light receiving element 53 from receiving the reflected light reflected by the transmission window 64. In particular, it is possible to prevent the light receiving element 53 from receiving the reflected light that becomes noise in the process of measuring the blood flow state, for example.

[0081] 10, the transmission window 64 is inclined so that the reflected light (see region C) reflected by the transmission window 64 strikes an area J2 other than the area J1 where the two light receiving elements 53 are arranged. This prevents the reflected light reflected by the transmission window 64 from striking the light receiving element 53 due to the inclination of the transmission window 64, thereby further preventing the light receiving element 53 from receiving the reflected light.

[0082] 9, the transmission window 64 is provided so that the window surfaces 64a and 64b are parallel to the line H between the two light receiving elements 53. Specifically, the transmission window 64 is provided so that both the lower window surface 64a and the upper window surface 64b are parallel to the line H between the light receiving elements.

[0083] This can prevent the reflected light from being biased toward the first light receiving element 53a side or the second light receiving element 53b side. That is, if the window surfaces 64a, 64b of the transmission window 64 are inclined with respect to the line H between the light receiving elements, the reflected light is biased toward either the first light receiving element 53a side or the second light receiving element 53b side, and the incident reflected light (noise) may differ between the two light receiving elements 53, resulting in a decrease in measurement accuracy. Therefore, the transmission window 64 is provided so that the window surfaces 64a, 64b are parallel to the line H between the light receiving elements 53 connecting the two light receiving elements 53, so that even if the reflected light slightly hits the light receiving element 53, the incident reflected light (in other words, noise) can be made uniform between the two light receiving elements 53. Therefore, for example, when differentially amplifying a signal indicating the light received by the two light receiving elements 53, the influence of the reflected light (noise) can be suppressed as much as possible, and as a result, a decrease in measurement accuracy can be suppressed.

[0084] In the above description, the transparent window 64 is provided so that the window surfaces 64a, 64b are parallel to the straight line H between the light receiving elements, but this is not limited to this. That is, as shown by imaginary lines in Fig. 9, the transparent window 64 may be provided so that the window surfaces 64a, 64b are inclined so as to be non-parallel to the straight line H between the light receiving elements.

[0085] The above-described embodiments and modifications can be combined as appropriate. For example, when there are multiple sensor units 40, the first embodiment and the second embodiment can be combined.

[0086] <Additional Notes> (1) A light emitting element that emits light toward an object; Two light receiving elements for receiving light from the object; a transparent window disposed between the light emitting element and the object, the transparent window transmitting light from the light emitting element; Equipped with The two light receiving elements are positioned concentrically with respect to the light emitting element and are positioned within a range of less than 180 degrees from the light emitting element as a center. (2) The two light receiving elements are arranged at a distance from each other. A sensor unit as described in (1). (3) The two light receiving elements are formed in a rectangular shape when viewed from above, and are arranged so that one side is parallel to a tangent to a concentric circle relative to the light emitting element. A sensor unit according to (1) or (2). (4) the light emitting element and the two light receiving elements are disposed on the same plane, The transmission window is provided so as to be inclined with respect to a straight line connecting the light emitting element and the two light receiving elements. The sensor unit according to any one of (1) to (3). (5) The two light receiving elements are arranged such that the center of the light receiving element is concentric with the light emitting element. The sensor unit according to any one of (1) to (4). (6) A sensor unit; A toilet seat provided with the sensor unit; Equipped with The sensor unit includes: A light emitting element that emits light toward an object; Two light receiving elements for receiving light from the object; a transparent window disposed between the light emitting element and the object, the transparent window transmitting light from the light emitting element; Equipped with The toilet seat apparatus, wherein the two light receiving elements are positioned concentrically with the light emitting element and positioned within a range of less than 180 degrees from the light emitting element as a center.

[0087] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0088] 20 Toilet seat device 30 Toilet Seat 40 Sensor unit 52 Light emitting element 53 Photodetector 64 Transparent window

Claims

1. A light emitting element that emits light toward an object; Two light receiving elements for receiving light from the object; a transparent window disposed between the light emitting element and the object, the transparent window transmitting light from the light emitting element; Equipped with The two light receiving elements are positioned on a concentric circle with respect to the light emitting element, and are positioned within a range of less than 180 degrees from the light emitting element as a center.

2. The two light receiving elements are disposed spaced apart from each other. The sensor unit according to claim 1 .

3. The two light receiving elements are formed to have a rectangular shape in a top view, and are arranged so that one side is parallel to a tangent to a concentric circle with respect to the light emitting element. The sensor unit according to claim 1 .

4. the light emitting element and the two light receiving elements are disposed on the same plane, the transmission window is provided so as to be inclined with respect to a straight line connecting the light emitting element and the two light receiving elements, The sensor unit according to claim 1 .

5. The two light receiving elements are arranged such that the center of the light receiving element is concentric with the light emitting element. The sensor unit according to claim 1 .

6. A sensor unit; A toilet seat provided with the sensor unit; Equipped with The sensor unit includes: A light emitting element that emits light toward an object; Two light receiving elements for receiving light from the object; a transparent window disposed between the light emitting element and the object, the transparent window transmitting light from the light emitting element; Equipped with A toilet seat apparatus, wherein the two light receiving elements are positioned concentrically with the light emitting element and positioned within a range of less than 180 degrees from the light emitting element as a center.

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