Rain detection device, rain detection system, and rain detection method

Abstract

To improve the detection accuracy of abnormal conditions in rain detection using infrared light.SOLUTION: The rain detection device includes a first data processing circuit 2 that converts a first detection signal from a first light-receiving element 11b, which receives first reflected light according to infrared light, into first detection data, and performs first data processing to detect rain on the basis of the first detection data, and a second data processing circuit 3 that performs second data processing to determine whether an abnormal state related to rain detection using infrared light has occurred. The first data processing circuit 2 further converts a second detection signal from a second light-receiving element 12b, which receives second reflected light according to ultraviolet light, into second detection data. The second data processing circuit 3, in the second data processing, determines whether an abnormal state related to rain detection using infrared light has occurred on the basis of the second detection data.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a rain detection device, a rain detection system, and a rain detection method. [Background technology]

[0002] Some conventional vehicles, such as automobiles, are equipped with a rain detection device called a rain sensor. In the rain detection device, a light-emitting element emits infrared light, which is reflected by the windshield, and a light-receiving element receives the reflected light. Rain is detected based on the detection result of the infrared light received by the light-receiving element.

[0003] Japanese Patent Publication No. 57-88346 (Patent Document 1) and Japanese Patent Publication No. 2014-211358 (Patent Document 2) disclose a rain detection device (rain sensor) that detects raindrops on a glass surface by irradiating light from a light-emitting element onto the glass surface and detecting the light reflected from the glass surface with a light-receiving element. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 57-88346 [Patent Document 2] JP 2014-211358 A [Summary] In the rain detection device described above, a technique for detecting an abnormal state of the rain detection device using infrared light has been studied. However, when infrared light is used to detect an abnormal state of the rain detection device, the infrared light used for abnormality detection may be affected by infrared light incident on the rain detection device from outside, which may result in a decrease in the accuracy of detecting an abnormal state of the rain detection device.

[0005] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to improve the accuracy of detecting an abnormal state in rain detection using infrared light.

[0006] A rain detection device according to one aspect of the present disclosure includes a first light-emitting element that emits infrared light, a first light-receiving element that receives first reflected light corresponding to the infrared light emitted from the first light-emitting element and outputs a first detection signal, a second light-emitting element that emits ultraviolet light, a second light-receiving element that receives second reflected light corresponding to the ultraviolet light emitted from the second light-emitting element and outputs a second detection signal, a first data processing circuit that converts the first detection signal into first detection data and performs first data processing to detect rain according to the first detection data, and a second data processing circuit that performs second data processing to determine whether an abnormal state has occurred in relation to rain detection using the infrared light emitted from the first light-emitting element, wherein the first data processing circuit further converts the second detection signal into second detection data, and the second data processing circuit determines whether an abnormal state has occurred according to the second detection data in the second data processing.

[0007] A rain detection system according to another aspect of the present disclosure includes a rain detection device that detects rain using infrared light, and a determination device that determines a rainfall state based on detection data from the rain detection device, wherein the rain detection device includes a first light-emitting element that emits infrared light, a first light-receiving element that receives first reflected light in response to the infrared light emitted from the first light-emitting element and outputs a first detection signal, a second light-emitting element that emits ultraviolet light, a second light-receiving element that receives second reflected light in response to the ultraviolet light emitted from the second light-emitting element and outputs a second detection signal, a first memory unit, and a second memory unit. The device includes a conversion circuit that converts the first detection signal into first detection data and stores the first detection data in a first memory unit, and the conversion circuit further converts the second detection signal into second detection data and stores the second detection data in a second memory unit. The determination device performs first data processing to detect rain in accordance with the first detection data stored in the first memory unit, and second data processing to determine whether an abnormal state has occurred regarding rain detection using infrared light emitted from the first light-emitting element in accordance with the second detection data stored in the second memory unit.

[0008] A rain detection method according to another aspect of the present disclosure includes the steps of: emitting infrared light from a first light-emitting element; converting a first detection signal output from a first light-receiving element that receives first reflected light corresponding to the infrared light emitted from the first light-emitting element into first detection data; emitting ultraviolet light from a second light-emitting element; converting a second detection signal output from a second light-receiving element that receives second reflected light corresponding to the ultraviolet light emitted from the second light-emitting element into second detection data; performing first data processing to detect rain according to the first detection data; and performing second data processing to determine whether an abnormal condition has occurred regarding rain detection using infrared light emitted from the first light-emitting element according to the second detection data. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of installation of a rain detection device according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing an example of the arrangement of light-emitting elements and light-receiving elements in the rain detection device according to the first embodiment. [Figure 3] FIG. 3 is a cross-sectional view showing the internal configuration of the rain detection device according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing an example of the configuration of a signal processing circuit in a rain detection system including the rain detection device according to the first embodiment. [Figure 5] FIG. 5 is a block diagram showing the relationship between the first and second light receiving elements and the ADC according to the first embodiment. [Figure 6] FIG. 6 is a flowchart showing wiper control and abnormality handling control using the rain detection device of the first embodiment. [Figure 7] FIG. 7 is a flowchart showing wiper control and abnormality handling control using the rain detection device of the first embodiment. [Figure 8] FIG. 8 is a diagram showing an example of the configuration of a signal processing circuit in a rain detection system including a rain detection device according to the second embodiment. [Figure 9]FIG. 9 is a flowchart showing wiper control and abnormality handling control of the rain detection system according to the second embodiment. [Figure 10] 10 is a flowchart showing wiper control and abnormality response control of the rain detection system of the second embodiment. [Detailed Description] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the same or corresponding parts in the drawings will be denoted by the same reference numerals, and their description will not be repeated in principle. Below, several embodiments will be described, but it has been intended from the beginning of the application that the configurations described in each embodiment will be appropriately combined.

[0010] <First Embodiment> [Example of installation of rain detection device 51] FIG. 1 is a diagram showing an example of installation of a rain detection device 51 according to the first embodiment. In the example of FIG. 1, a side view of a vehicle 100 is shown. FIG. 1 shows a configuration in which the rain detection device 51 is installed inside a glass windshield 60 of the vehicle 100, such as an automobile. The windshield 60 is a transparent plate-like body. As shown in FIG. 3, the windshield 60 has a structure that suppresses transmission of ultraviolet light.

[0011] The rain detection device 51 is a rain sensor that detects rain including raindrops on the vehicle 100. In the rain detection device 51, a plurality of light-emitting elements and a plurality of light-receiving elements are provided on a circuit board 10 provided inside the housing of the rain detection device 51, as shown in FIG.

[0012] [Example of arrangement of light-emitting elements and light-receiving elements in rain detection device 51] Fig. 2 is a diagram showing an example of the arrangement of light-emitting elements and light-receiving elements in the rain detection device 51 according to embodiment 1. Fig. 2 shows an example of the arrangement of light-emitting elements and light-receiving elements in the rain detection device 51 as viewed from the windshield 60 side.

[0013] On the circuit board 10, a first light emitting element 11a, a first light receiving element 11b, a second light emitting element 12a, and a second light receiving element 12b are provided.

[0014] The first light-emitting element 11a is a light-emitting element made of an LED that emits infrared light. The first light-receiving element 11b is a light-receiving element made of a photodiode that receives infrared light. The first light-receiving element 11b is provided at a position where it can receive first reflected light 14a corresponding to the infrared light 14 emitted by the first light-emitting element 11a.

[0015] The second light-emitting element 12a is a light-emitting element made of an LED that emits ultraviolet light. The second light-receiving element 12b is a light-receiving element made of a photodiode that receives ultraviolet light. The second light-receiving element 12b is provided at a position where it can receive second reflected light 15a corresponding to the ultraviolet light 15 emitted by the second light-emitting element 12a.

[0016] The rain detection device 51 has a lens 13 on the side that contacts the windshield 60. The lens 13 is a transparent lens with a conical shape as shown in FIG. 3. The first light-emitting element 11a and the first light-receiving element 11b are disposed in positions that face each other across the lens 13 when the circuit board 10 and the lens 13 are viewed in plan. The second light-emitting element 12a and the second light-receiving element 12b are disposed in positions that face each other across the lens 13 when the circuit board 10 and the lens 13 are viewed in plan.

[0017] The first light-emitting element 11a and the first light-receiving element 11b, and the second light-emitting element 12a and the second light-receiving element 12b are arranged in a direction in which the paths of the infrared light 14 and the first reflected light 14a intersect with the paths of the ultraviolet light 15 and the second reflected light 15a.

[0018] In addition, the first light-emitting element 11a and the first light-receiving element 11b, and the second light-emitting element 12a and the second light-receiving element 12b may be arranged in a direction such that the paths of the infrared light 14 and the first reflected light 14a do not intersect with the paths of the ultraviolet light 15 and the second reflected light 15a.

[0019] Infrared light 14 emitted from the first light-emitting element 11a passes through the lens 13 and enters the front window 60 shown in FIG. 1. First reflected light 14a, which consists of infrared light reflected by the front window 60, passes through the lens 13 and is received by the first light-receiving element 11b. Ultraviolet light 15 emitted from the second light-emitting element 12a passes through the lens 13 and enters the front window 60. Second reflected light 15a, which consists of ultraviolet light reflected by the front window 60, passes through the lens 13 and is received by the second light-receiving element 12b.

[0020] [Example of the internal configuration of the rain detection device 51] Fig. 3 is a cross-sectional view showing the internal configuration of the rain detection device 51 according to the first embodiment. Fig. 3 shows the internal configuration of the housing 9 of the rain detection device 51 attached to the windshield 60. In Fig. 3, only a part of the windshield 60 is shown in cross section to clearly show the state of ultraviolet light inside.

[0021] The internal configuration of the rain detection device 51 will be described below with reference to Fig. 3. In the following description, the configuration will be described with the rain detection device 51 placed on a flat surface with the opening 91 of the housing 9 facing upward. Therefore, when describing the up-down direction, it means the up-down direction in a state where the rain detection device 51 is placed on a flat surface with the opening 91 of the housing 9 facing upward. Therefore, in the following description, the up-down direction means the up-down direction in the state of Fig. 3, and the down-down direction means the down-down direction in the state of Fig. 3.

[0022] In the rain detection device 51, a housing 9 has therein a circuit board 10, a first light-emitting element 11a, a first light-receiving element 11b, a second light-emitting element 12a, a second light-receiving element 12b, and a lens 13.

[0023] The housing 9 is made of a non-transparent resin and has an opening 91 formed on the upper surface side of the rectangular parallelepiped. In the internal space of the housing 9, a circuit board 10 is provided on a bottom surface 92 of the housing 9. A first light-emitting element 11a, a first light-receiving element 11b, a second light-emitting element 12a, and a second light-receiving element 12b are provided on the circuit board 10. In FIG. 3, the first light-emitting element 11a and the first light-receiving element 11b are not shown in order to clearly show the arrangement of the second light-emitting element 12a and the second light-receiving element 12b.

[0024] A thin transparent plate 80 is attached above the opening 91 of the housing 9, and comes into contact with the windshield 60 when the rain detection device 51 is attached to the windshield 60. The transparent plate 80 is made of a light-transmitting resin and has the property of being adhesive to the windshield 60. In this way, the transparent plate 80 is used as a light-transmitting adhesive member that can adhere the rain detection device 51 to the windshield 60.

[0025] A conical lens 13 is attached to the center of the inside of the transparent plate 80. The lens 13 is made of a transparent resin that can transmit the infrared light emitted from the first light-emitting element 11a and the ultraviolet light emitted from the second light-emitting element 12a. The lens 13 may have a shape other than a cone. The lens 13 may also be made of transparent glass that can transmit the infrared light and ultraviolet light.

[0026] The windshield 60 is made of triple-layer glass (glass with a triple-layer structure) with an intermediate layer 62 that suppresses transmission of ultraviolet light between two glass layers 61, 61. The intermediate layer 62 is, for example, transparent glass containing an ultraviolet light absorber. In the windshield 60, ultraviolet light that enters from the outside of the windshield 60 (the outside of the vehicle 100 in FIG. 1 ) is absorbed by the intermediate layer 62, thereby suppressing transmission of the ultraviolet light that enters from the outside of the windshield 60 to the inside of the windshield 60.

[0027] The rain detection device 51 is attached to the inside of the windshield 60 in such a manner that the transparent plate 80 is in close contact with the inside of the windshield 60 .

[0028] [Example of rain detection by rain detector 51] Next, an example of rain detection in the rain detection device 51 will be described with reference to Figures 2 and 3. In the rain detection device 51, the first light-emitting element 11a and the first light-receiving element 11b shown in Figure 2 are used to detect rain. The infrared light emitted by the first light-emitting element 11a is incident on the lens 13. The infrared light incident on the lens 13 then passes through the interior of the lens 13 and the transparent plate 80, and enters the windshield 60.

[0029] When infrared light is incident on the windshield 60 from inside the windshield 60, if there is no raindrops or other precipitation on the outside of the windshield 60, the infrared light is reflected inside the windshield 60 toward the inside of the windshield 60. On the other hand, when infrared light is incident on the windshield 60 from inside the windshield 60, if there is raindrops or other precipitation on the outside of the windshield 60, the infrared light is not reflected inside the windshield 60 but passes through the windshield 60 and is emitted toward the outside of the windshield 60.

[0030] First reflected light 14a, which is infrared light reflected inside front window 60 due to rain on the outside of front window 60, travels from front window 60 through transparent plate 80 and enters lens 13. Then, first reflected light 14a that has entered lens 13 passes through the inside of lens 13 and is emitted toward first light receiving element 11b. First reflected light 14a that has exited lens 13 can be incident on first light receiving element 11b.

[0031] In the rain detection device 51, when rain containing raindrops is on the windshield 60, the amount of first reflected light 14a detected decreases as the amount of first reflected light 14a reflected by the windshield 60 decreases compared to when there is no rain containing raindrops on the windshield 60. This is because when there is rain containing raindrops on the windshield 60, the amount of infrared light escaping from the windshield 60 to the outside increases compared to when there is no rain containing raindrops on the windshield 60. Therefore, the rain detection device 51 can detect the rainfall state by detecting the amount of first reflected light 14a reflected inward by the windshield 60.

[0032] [Detection example of abnormal state regarding rain detection by rain detection device 51] Next, an example of detecting an abnormal state regarding rain detection by the rain detection device 51 will be described with reference to FIGS.

[0033] In the rain detection device 51, the second light-emitting element 12a and the second light-receiving element 12b are used to detect an abnormal state related to rain detection in the rain detection device 51. As shown in Fig. 3, ultraviolet light 15 emitted by the second light-emitting element 12a is incident on the lens 13. Then, the ultraviolet light 15 incident on the lens 13 passes through the inside of the lens 13 and the transparent plate 80, and is incident on the windshield 60.

[0034] On the front window 60, the incident ultraviolet light 15 is absorbed by the intermediate layer 62 or reflected toward the inside of the front window 60. The ultraviolet light reflected on the intermediate layer 62 of the front window 60, that is, second reflected light 15a, passes through the front window 60 and the transparent plate 80 and enters the lens 13. The second reflected light 15a that enters the lens 13 then passes through the inside of the lens 13 and is emitted toward the second light receiving element 12b. The second reflected light 15a that exits from the lens 13 can enter the second light receiving element 12b.

[0035] 3, ultraviolet light entering the windshield 60 from the outside is prevented from entering the windshield 60 by being absorbed or reflected by the intermediate layer 62. Therefore, when ultraviolet light is used as light for detecting an abnormal state of the rain detection device 51, the same type of light that may reduce the accuracy of detecting an abnormal state is suppressed compared to when infrared light is used as light for detecting an abnormal state of the rain detection device 51, and therefore the accuracy of detecting an abnormal state related to rain detection by the rain detection device 51 can be improved.

[0036] In the rain detection device 51, when the amount of second reflected light 15a detected by the second light receiving element 12b is outside a predetermined range of judgment values, it can be determined that an abnormal state regarding rain detection has occurred in the rain detection device 51. The judgment value for determining such an abnormal state is set, for example, outside the range of the amount of second reflected light 15a that can be detected by the second light receiving element 12b in the rain detection device 51 under normal conditions.

[0037] Abnormal conditions related to rain detection by the rain detection device 51 include electrical abnormal conditions and physical abnormal conditions. An electrical abnormal condition is an abnormal condition related to an electrical failure, such as an abnormal state of the electrical circuits and elements provided on the circuit board 10. A physical abnormal condition is an abnormal condition related to a physical failure, such as an improper installation of the rain detection device 51 on the windshield 60 or damage to a structure such as the lens 13.

[0038] [Configuration example of a signal processing circuit of the rain detection system 50 including the rain detection device 51] 4 is a diagram showing an example of the configuration of a signal processing circuit related to a rain detection system 50 including a rain detection device 51 according to embodiment 1. The rain detection system 50 includes the rain detection device 51 and a control device 52 that controls the entire vehicle 100.

[0039] In the rain detection device 51, a circuit board 10 is provided with a first data processing circuit 2, a second data processing circuit 3, a non-volatile memory 4, a first light-emitting element 11a, a first light-receiving element 11b, a second light-emitting element 12a, and a second light-receiving element 12b.

[0040] The first data processing circuit 2 is configured by a computer including a CPU (Central Processing Unit) 21, a ROM (Read Only Memory) 22, a RAM (Random Access Memory) 23, a first register 24, a second register 25, an ADC (Analog Digital Converter) 26, a switching circuit 27, and an input / output buffer (not shown). The first data processing circuit 2 is configured by an IC chip such as an ASIC (Application Specific Integrated Circuit). In the first data processing circuit 2, the CPU 21, the ROM 22, the RAM 23, the first register 24, and the second register 25 are a part that processes digital data and are called an internal circuit 20. Note that the internal circuit 20 may include components other than those described above.

[0041] The ROM 22 stores various software programs that indicate processing procedures related to the controls executed by the first data processing circuit 2. The CPU 21 loads the software programs stored in the ROM 22 into the RAM 23 or the like and executes them.

[0042] The second data processing circuit 3 is configured by a computer including a CPU 31, a ROM 32, a RAM 33, an input / output buffer (not shown), etc. The second data processing circuit 3 is configured by an IC chip such as an ASIC. The first data processing circuit 2 is configured by an IC chip such as an ASIC.

[0043] The ROM 32 stores various software programs that indicate processing procedures related to the controls executed by the second data processing circuit 3. The CPU 31 loads the software programs stored in the ROM 32 into the RAM 33 or the like and executes them.

[0044] A first light-emitting element 11a, a first light-receiving element 11b, a second light-emitting element 12a, and a second light-receiving element 12b are connected to the first data processing circuit 2. The first data processing circuit 2 controls the emission of infrared light in the first light-emitting element 11a by transmitting a control signal to the first light-emitting element 11a. The first data processing circuit 2 controls the emission of ultraviolet light in the second light-emitting element 12a by transmitting a control signal to the second light-emitting element 12a.

[0045] A first detection signal corresponding to the infrared light received by the first light receiving element 11b is input from the first light receiving element 11b to the first data processing circuit 2. A second detection signal corresponding to the ultraviolet light received by the second light receiving element 12b is input from the second light receiving element 12b to the first data processing circuit 2.

[0046] In the first data processing circuit 2, the first detection signal, which is an analog signal input from the first light receiving element 11b in response to the infrared light received by the first light receiving element 11b, is converted into first detection data, which is digital data, by the ADC 26. In the first data processing circuit 2, the first detection data is stored in a first register 24, which is a first storage unit.

[0047] In the first data processing circuit 2, the second detection signal, which is an analog signal input from the second light receiving element 12b in response to the ultraviolet light received by the second light receiving element 12b, is converted into second detection data, which is digital data, by the ADC 26. In the first data processing circuit 2, the second detection data is stored in a second register 25, which is a second storage unit.

[0048] The switching circuit 27 is a switch that switches between the first light receiving element 11b and the second light receiving element 12b as the light receiving element input to the ADC 26. The switching circuit 27 will be specifically described with reference to FIG.

[0049] The rain detection device 51 detects rain as follows: The rate at which the infrared light emitted from the first light-emitting element 11a is reflected by the windshield 60 differs depending on whether there is rain, including raindrops, on the outside of the windshield 60 or whether there is no rain, including raindrops. Therefore, even if the first light-emitting element 11a emits the same amount of infrared light 14, the amount of first reflected light 14a, which is infrared light, received by the first light-receiving element 11b differs between when it is raining and when it is not raining.

[0050] In the rain detection device 51, the second data processing circuit 3 executes a rain detection process to detect rain in response to a first detection signal input from the first light receiving element 11b. In the rain detection process, for example, when it is determined that the amount of infrared light received by the first light receiving element 11b is equal to or greater than a first threshold, a process is executed to determine that rain has been detected. In addition, in the rain detection process, it is possible to detect a first amount of rain based on the first threshold, and a second amount of rain based on the second threshold. For example, rain with a first amount of rain corresponds to a first-stage rainfall state (a rainfall state with a relatively light amount of rain), and rain with a second amount of rain corresponds to a second-stage rainfall state (a rainfall state with a relatively heavy amount of rain), which is heavier than the first-stage rainfall state.

[0051] In the rain detection process, when the data on the amount of the first reflected light 14a received by the first light receiving element 11b is equal to or greater than the first threshold data and is less than the second threshold data, it is determined that rain of a first amount has been detected. In the rain detection process, when the data on the amount of the first reflected light 14a received by the first light receiving element 11b is equal to or greater than the second threshold data, it is determined that rain of a second amount has been detected.

[0052] The rain detection device 51 detects an abnormal state as follows. For example, if the aforementioned electrical abnormal state or the aforementioned physical abnormal state occurs, when the second light-emitting element 12a emits ultraviolet light 15, the signal level of the second detection signal input from the second light-receiving element 12b in accordance with the second reflected light 15a received by the second light-receiving element 12b may become higher or lower than the normal range. Therefore, even if the second light-emitting element 12a emits the same amount of ultraviolet light 15, the amount of second reflected light 15a received by the second light-receiving element 12b will differ between the normal state and the abnormal state.

[0053] In the rain detection device 51, the second data processing circuit 3 executes an abnormality detection process for detecting an abnormality related to rain detection, in which the second data processing circuit 3 determines that an abnormality has been detected in response to the second detection signal input from the second light receiving element 12b. For example, when the amount of second reflected light 15a received by the second light receiving element 12b becomes equal to or less than a third threshold value that is less than a reference value by a predetermined amount of light, or when the amount of second reflected light 15a received by the second light receiving element 12b becomes equal to or greater than a fourth threshold value that is more than the reference value by a predetermined amount of light, the second data processing circuit 3 executes an abnormality detection process for detecting an abnormality related to rain detection in the rain detection device 51.

[0054] The nonvolatile memory 4 is connected to both the first data processing circuit 2 and the second data processing circuit 3. The nonvolatile memory 4 stores infrared light determination data for determining rain in the rain detection process described above, and ultraviolet light determination data for determining an abnormal state in the abnormality detection process described above. The infrared light determination data includes the first threshold data and second threshold data described above. The ultraviolet light determination data includes the third threshold data and fourth threshold data described above. The nonvolatile memory 4 may be any type of memory, such as an EPROM (Erasable Programmable Read Only Memory), as long as the stored data is retained even when power is not supplied.

[0055] The second data processing circuit 3 reads out the infrared light determination data and the ultraviolet light determination data from the nonvolatile memory 4, stores the data in RAM 33 of the second data processing circuit 3, and sends the data to the first data processing circuit 2. The first data processing circuit 2 stores the infrared light determination data and the ultraviolet light determination data sent from the second data processing circuit 3 in RAM 23. The infrared light determination data and the ultraviolet light determination data may be sent directly from the nonvolatile memory 4 to the first data processing circuit 2 in response to an instruction from the second data processing circuit 3.

[0056] The first data processing circuit 2 uses the infrared light determination data to determine whether the detection state of the first reflected light 14a has changed from a reference state. The reference state in this determination is a state where it is not raining. Specifically, the first data processing circuit 2 determines that a state change has occurred in the detection state of the first reflected light 14a when the first detection data indicating the amount of first reflected light 14a received by the first light receiving element 11b is equal to or greater than the first threshold value.

[0057] The first data processing circuit 2 uses the ultraviolet light determination data to determine whether the detection state of the second reflected light 15a has changed from a reference state. The reference state in this determination is a normal state (a state in which no abnormality has occurred). Specifically, the first data processing circuit 2 determines that a state change has occurred in the detection state of the second reflected light 15a when the second detection data indicating the amount of second reflected light 15a received by the second light receiving element 12b is equal to or less than the third threshold value or equal to or greater than the fourth threshold value.

[0058] The second data processing circuit 3 determines the type of state change when the first data processing circuit 2 determines that there has been a state change in the detection state of the first reflected light 14a, and when the first data processing circuit 2 determines that there has been a state change in the detection state of the second reflected light 15a.

[0059] The type of state change refers to the type of state change when state changes are categorized, such as a change from no rain to light rain, a change from no rain or light rain to heavy rain, and a change from a normal state to an abnormal state regarding rain detection.

[0060] When the first data processing circuit 2 determines that there has been a change in the detection state of the first reflected light 14a, the second data processing circuit 3 determines the type of state change by comparing the first detection data with the first threshold value and the second threshold value in the infrared light determination data.

[0061] When the first data processing circuit 2 determines that there has been a change in the detection state of the second reflected light 15a, the second data processing circuit 3 determines the type of state change by comparing the second detection data with the third and fourth thresholds in the ultraviolet light determination data.

[0062] The control device 52 includes an ECU (Electronic Control Unit) 7. The ECU 7 is a computer that controls various systems in the vehicle 100. The controls performed by the ECU 7 include control of operating a wiper device provided in the vehicle 100 based on detection data related to rain detected by the rain detection device 51. The ECU 7 includes a CPU 71, a ROM 72, a RAM 73, an input / output buffer (not shown), and the like. The ECU 7 is configured with an IC chip such as an ASIC.

[0063] The ROM 72 stores various software programs that indicate processing procedures related to the controls executed by the ECU 7. The CPU 71 loads the software programs stored in the ROM 72 onto the RAM 73 or the like and executes them.

[0064] Various data related to rain detection are transmitted and received between the rain detection device 51 and the control device 52. Therefore, the control device 52 is also a device equipped with functions related to rain detection. As a result, it can be said that the rain detection device 51 and the control device 52 constitute a rain detection system 50.

[0065] For example, when the second data processing circuit 3 determines the type of state change as described above, it transmits data relating to the determination result of the type of state change to the ECU 7. In response to receiving such data, the ECU 7 executes the following control. When the determination result data received from the second data processing circuit 3 is data relating to a state change of the rain detection state, the ECU 7 executes control relating to the wiper device provided on the vehicle 100. Furthermore, when the determination result data received from the second data processing circuit 3 is data relating to a state change to an abnormal state, the ECU 7 executes control to deal with the abnormal state.

[0066] [Relationship between the first light receiving element 11b, the second light receiving element 12b, and the ADC 26] FIG. 5 is a block diagram showing the relationship between the first light receiving element 11b, the second light receiving element 12b, and the ADC 26 according to the first embodiment.

[0067] In the first data processing circuit 2, the first light-emitting element 11a, the first light-receiving element 11b, the second light-emitting element 12a, and the second light-receiving element 12b are connected as follows: The first light-emitting element 11a (the first light-emitting element 11a shown by a solid line in FIG. 5) is connected to the first terminal 201. The second light-emitting element 12a is connected to the second terminal 202. The first light-receiving element 11b is connected to the third terminal 203. The second light-receiving element 12b is connected to the fourth terminal 204. The first terminal 201 and the second terminal 202 are connected to the internal circuit 20. The ADC 26 is connected to the internal circuit 20.

[0068] In the first data processing circuit 2, a switching circuit 27 is provided between the ADC 26 and the third terminal 203 and fourth terminal 204. The switching circuit 27 includes a first switch 271 and a second switch 272. The first switch 271 is provided between the ADC 26 and the third terminal 203. The second switch 272 is provided between the signal path between the ADC 26 and the first switch 271 and the fourth terminal 204.

[0069] 5, in the switching circuit 27, when the first switch 271 is turned on, the second switch 272 is turned off. On the other hand, in the switching circuit 27, when the first switch 271 is turned off, the second switch 272 is turned on.

[0070] With this configuration, in the switching circuit 27, only when the first switch 271 is in the on state, the first detection signal corresponding to the first reflected light 14a received by the first light receiving element 11b is converted from an analog signal to digital data in the ADC 26 and input to the internal circuit of the first data processing circuit 2. As a result, only when the first switch 271 is in the on state in the switching circuit 27, the first detection signal corresponding to the first reflected light 14a received by the first light receiving element 11b is processed as a valid detection signal in the first data processing circuit 2.

[0071] On the other hand, only when the second switch 272 is in the on state, the detection signal corresponding to the second reflected light 15a received by the second light receiving element 12b is converted from an analog signal to digital data in the ADC 26 and input to the internal circuit 20 of the first data processing circuit 2. As a result, only when the second switch 272 is in the on state in the switching circuit 27, the second detection signal corresponding to the second reflected light 15a received by the second light receiving element 12b is processed as a valid detection signal in the first data processing circuit 2.

[0072] The second light-emitting element 12a may be configured by connecting the first light-emitting element 11a and the second light-emitting element 12a in series, as indicated by the dashed line in Fig. 5. In this case, the first light-emitting element 11a and the second light-emitting element 12a emit light simultaneously when a control signal is simultaneously supplied from the internal circuit 20 to the first light-emitting element 11a and the second light-emitting element 12a.

[0073] Even in this configuration in which the first light-emitting element 11a and the second light-emitting element 12a emit light simultaneously, the switching circuit 27 allows only one of the first light-receiving element 11b and the second light-receiving element 12b to receive light. Therefore, it is possible to detect rain using infrared light and detect abnormal conditions using ultraviolet light, just as in the configuration in which the first light-emitting element 11a is connected to the first terminal 201 and the second light-emitting element 12a is connected to the second terminal 202.

[0074] When such a configuration is adopted, the number of terminals connecting the first light-emitting element 11a and the second light-emitting element 12a in the first data processing circuit 2 can be reduced compared to a configuration in which the first light-emitting element 11a is connected to the first terminal 201 and the second light-emitting element 12a is connected to the second terminal 202. The first light-emitting element 11a and the second light-emitting element 12a may also be connected in parallel. Even with such a configuration, it is possible to obtain the same technical effect as with a configuration in which the first light-emitting element 11a and the second light-emitting element 12a are connected in series.

[0075] [Wiper control and abnormality response control in rain detection device 51] Next, wiper control and abnormality response control using the rain detection device 51 of embodiment 1 will be described. Figures 6 and 7 are flowcharts showing wiper control and abnormality response control using the rain detection device 51 of embodiment 1. In Figures 6 and 7, a series of flowcharts show the controls executed by the rain detection device 51 and the control device 52 in cooperation with each other.

[0076] 6 and 7 are executed by the CPU 21 of the first data processing circuit 2 and the CPU 31 of the second data processing circuit 3 in the rain detection device 51, and the CPU 71 of the ECU 7 in the control device 52. The process shown in FIG. 6 is executed once when the rain detection device 51 is started. The process shown in FIG. 7 is executed repeatedly after the control executed when the rain detection device 51 is started is completed.

[0077] 6, a process executed at the start of the rain detection device 51 will be described. In the control device 52, the ECU 7 sends an operation start command to the second data processing circuit 3 of the rain detection device 51, as shown in step S1.

[0078] In the rain detection device 51, when the second data processing circuit 3 receives the operation start command sent in step S1, the following process is performed as shown in step S2. In step S2, the second data processing circuit 3 reads the infrared light determination data and the ultraviolet light determination data from the nonvolatile memory 4. The second data processing circuit 3 then stores the read infrared light determination data and the ultraviolet light determination data in the RAM 33 and sends the infrared light determination data and the ultraviolet light determination data to the first data processing circuit 2.

[0079] In the rain detection device 51, as shown in step S3, the first data processing circuit 2 stores the infrared light determination data and ultraviolet light determination data sent in step S2 in the RAM 23, and the process ends.

[0080] Next, referring to Fig. 7, the processing of the rain detection device 51 and the control device 52 executed after the rain detection device 51 is started will be described. The processing related to rain detection using infrared light shown in steps S11 and S12 and the processing related to abnormal state detection using ultraviolet light shown in steps S13 and S14 are executed alternately and repeatedly at a fixed cycle. Therefore, when the series of processing shown in Fig. 7 is executed, if steps S11 and S12 are executed, steps S13 and S14 are not executed, and if steps S13 and S14 are executed, steps S11 and S12 are not executed. Switching between the processing related to light detection using infrared light and the processing related to light detection using ultraviolet light is executed by the first data processing circuit 2 controlling the switching circuit 27 shown in Fig. 5.

[0081] In addition, the period in which the process for detecting rain using infrared light is executed and the period in which the process for detecting an abnormal state using ultraviolet light is executed may be the same period or different periods.

[0082] At the timing when steps S11 and S12 are executed, as shown in step S11, the first data processing circuit 2 of the rain detection device 51 causes the first light-emitting element 11a to emit infrared light 14, and stores in the first register 24 the first detection data converted from the first detection signal output from the first light-receiving element 11b in accordance with the first reflected light 14a received by the first light-receiving element 11b.

[0083] When steps S11 and S12 are executed, as shown in step S12, the first data processing circuit 2 compares the first detection data stored in the first register 24 with the infrared light determination data stored in the RAM 23 in step S2, determines whether or not there has been a state change from the reference state for the infrared light, and proceeds to step S15.

[0084] In step S12, if the first detection data is less than the first threshold value of the infrared light determination data, it is determined that there is no state change.In step S12, if the first detection data is equal to or greater than the first threshold value of the infrared light determination data, it is determined that there is a state change.

[0085] At the timing when steps S13 and S14 are executed, as shown in step S13, the first data processing circuit 2 of the rain detection device 51 causes the second light-emitting element 12a to emit ultraviolet light 15, and stores in the second register 25 the second detection data converted from the second detection signal output from the second light-receiving element 12b in accordance with the second reflected light 15a received by the second light-receiving element 12b.

[0086] When steps S13 and S14 are executed, as shown in step S14, the first data processing circuit 2 compares the second detection data stored in the second register 25 with the ultraviolet light judgment data stored in the RAM 23 in step S2, determines whether or not there has been a state change from the reference state for the ultraviolet light, and proceeds to step S15.

[0087] In step S14, if the second detection data is greater than the third threshold and less than the fourth threshold, it is determined that there is no change in the detection state of the second reflected light 15a.In step S14, if the second detection data is equal to or less than the third threshold or equal to or greater than the fourth threshold, it is determined that there has been a change in the state of the ultraviolet light from the reference state.

[0088] As shown in step S15, the first data processing circuit 2 of the rain detection device 51 determines whether it is determined in step S12 or step S14 that there has been a state change in the infrared light or the ultraviolet light. Specifically, in step S15, in the cycle in which steps S11 and S12 are executed, it determines whether it is determined in step S12 that there has been a state change in the infrared light. In step S15, in the cycle in which steps S13 and S14 are executed, it determines whether it is determined in step S14 that there has been a state change in the ultraviolet light.

[0089] If it is determined in step S15 that there has been no state change, the process ends. On the other hand, if it is determined in step S15 that there has been a state change, the first data processing circuit 2 sends an interrupt signal and light type data to the second data processing circuit 3, as shown in step S16. The light type data is data indicating whether the type of light being determined in step S15 to be a state change is infrared light in steps S11 and S12, or ultraviolet light in steps S13 and S14.

[0090] Upon receiving the interrupt signal and light type data sent in step S16, the second data processing circuit 3 performs the following process as shown in step S17. In step S17, the second data processing circuit 3 determines the type of state change in accordance with the light type data received from the first data processing circuit 2 and the detection data in which it was determined in step S15 that a state change has occurred, and sends determination result data on the type of state change to the ECU 7 of the control device 52.

[0091] Specifically, in step S17, if the light type data sent from the first data processing circuit 2 together with the interrupt signal indicates infrared light, the second data processing circuit 3 reads the first detection data from the first register 24 and reads the infrared light determination data from the RAM 33. Then, the second data processing circuit 3 compares the first detection data with the infrared light determination data to determine the type of state change.

[0092] In step S17, if the light type data sent from the first data processing circuit 2 together with the interrupt signal indicates ultraviolet light, the second data processing circuit 3 reads the second detection data from the second register 25 and reads the ultraviolet light determination data from the RAM 33. Then, the second data processing circuit 3 compares the second detection data with the ultraviolet light determination data to determine the type of state change.

[0093] In step S17, for example, the following determinations are made. If the first detection data is equal to or greater than the first threshold value of the infrared light determination data and less than the second threshold value, the second data processing circuit 3 determines that the type of state change is a state in which a first amount of rain (a relatively light amount of rain) has been detected. If the first detection data is equal to or greater than the second threshold value of the infrared light determination data, the second data processing circuit 3 determines that the type of state change is a state in which a second amount of rain (a relatively heavy amount of rain) has been detected. If the second detection data is equal to or less than the third threshold value of the ultraviolet light determination data or equal to or greater than the fourth threshold value, the second data processing circuit 3 determines that the type of state change is a state in which an abnormal state of the rain detection device 51 has been detected.

[0094] When the ECU 7 receives the determination result data sent in step S17, it checks the determination result data for the type of state change as shown in step S18. As shown in step S19, the ECU 7 determines whether the determination result data checked in step S18 is a determination result that an abnormal state of the rain detection device 51 has been detected.

[0095] In step S19, if it is determined that the determination result data is not a determination result that an abnormal state of the rain detection device 51 has been detected, it is determined that the determination result data is a determination result that rain has been detected. In this case, as shown in step S20, the ECU 7 controls the wipers provided on the vehicle 100 in accordance with the determination result data, and the process ends.

[0096] In step S20, if it is determined that the type of state change is a state in which a first amount of rain has been detected, the ECU 7 operates the wiper device at a first speed, which is a low speed, and if it is determined that the type of state change is a state in which a second amount of rain has been detected, the ECU 7 executes control to operate the wiper device at a second speed, which is faster than the first speed.

[0097] On the other hand, if it is determined in step S19 that the determination result data indicates that an abnormal state of the rain detection device 51 has been detected, the ECU 7 performs abnormality response control in accordance with the determination result data, as shown in step S21, and then ends the process. The abnormality response control executed in step S21 involves issuing an alarm from an alarm device provided in the vehicle 100. The alarm may be any one of a sound output alarm, an image displayed on a display device, or an illumination emitted by a light-emitting device, or a combination of these alarms. The issuance of such an alarm allows people inside the vehicle to know that an abnormal state has occurred.

[0098] In the first embodiment described above, the accuracy of detecting an abnormal state related to rain detection using infrared light can be improved for the following reasons: the first data processing circuit 2 performs first data processing to detect rain in accordance with first detection data obtained by converting a first detection signal output from the first light receiving element 11b that receives the first reflected light 14a, which is infrared light; and the second data processing circuit 3 performs second data processing to determine whether an abnormal state related to rain detection has occurred in accordance with second detection data obtained by converting a second detection signal output from the second light receiving element 12b that receives the second reflected light 15a, which is ultraviolet light. Because the rain detection device 51 determines whether an abnormal state related to rain detection has occurred using the second reflected light 15a, which is ultraviolet light, the accuracy of detecting an abnormal state related to rain detection using infrared light can be improved in an environment that is susceptible to the influence of infrared light, such as the inside of the windshield 60.

[0099] Furthermore, in embodiment 1, whether or not an abnormal state regarding rain detection has occurred is determined by comparing the ultraviolet light determination data stored in the non-volatile memory 6 with the second detection data, which is the detection data of ultraviolet light detected by the second light receiving element 12b, so that whether or not an abnormal state regarding rain detection has occurred can be determined based on predetermined determination data.

[0100] In the first embodiment, the rain detection device 51 is attached to the windshield 60 so that the first light-emitting element 11a, the first light-receiving element 11b, the second light-emitting element 12a, and the second light-receiving element 12b are arranged facing the windshield 60, which is made of a three-layer glass structure having an intermediate layer 62 between two glass layers 61 that suppresses transmission of ultraviolet light. As a result, the intermediate layer 62 prevents ultraviolet light traveling from the outside of the windshield 60 to the inside of the windshield 60 from transmitting into the inside of the windshield 60. The second reflected light 15a received by the second light-receiving element 12b is ultraviolet light that is reflected by the intermediate layer 62 out of the ultraviolet light 15 emitted from the second light-emitting element 12a. Therefore, the second reflected light 15a received by the second light-receiving element 12b is less susceptible to the ultraviolet light traveling from the outside of the windshield 60 to the inside of the windshield 60. As a result, the rain detection device 51 uses ultraviolet light to detect abnormal conditions related to rain detection in an environment that is less susceptible to the influence of ultraviolet light from outside the windshield 60, thereby improving the accuracy of detecting abnormal conditions related to rain detection.

[0101] Furthermore, in the first embodiment, the abnormal conditions related to rain detection determined by the second data processing circuit 3 include electrical failures in the rain detection device 51, and therefore, abnormal conditions related to rain detection including electrical failures can be detected.

[0102] Furthermore, in the first embodiment, the abnormal conditions related to rain detection determined by the second data processing circuit 3 include physical failures of the rain detection device 51, and therefore, abnormal conditions related to rain detection including physical failures can be detected.

[0103] <Embodiment 2> In the second embodiment, a rain detection system 50A will be described in which a control device 52A determines an abnormal state regarding rain detection as described in the first embodiment. The rain detection device 51A according to the second embodiment has a similar configuration to the rain detection device 51 according to the first embodiment shown in FIGS.

[0104] A rain detection device 51A according to the second embodiment is provided in the vehicle 100 shown in Fig. 1 at a position similar to that of the rain detection device 51 according to the first embodiment. The rain detection device 51A according to the second embodiment is provided with a circuit board 10A instead of the circuit board 10 shown in Figs. 2 and 3.

[0105] [Configuration example of a signal processing circuit of the rain detection system 50A including the rain detection device 51A] 8 is a diagram showing an example of the configuration of a signal processing circuit related to a rain detection system 50A including a rain detection device 51A according to Embodiment 2. The rain detection system 50A includes the rain detection device 51A and a control device 52A that controls the entire vehicle 100.

[0106] In the rain detection device 51A, a data processing circuit 2A, a first light-emitting element 11a, a first light-receiving element 11b, a second light-emitting element 12a, and a second light-receiving element 12b are provided on a circuit board 10A.

[0107] 4, the data processing circuit 2A is configured by a computer including a CPU 21, a ROM 22, a RAM 23, a first register 24, a second register 25, an ADC 26, a switching circuit 27, an input / output buffer (not shown), etc. The first data processing circuit 2 is configured by an IC chip such as an ASIC.

[0108] 4, a first light-emitting element 11a, a first light-receiving element 11b, a second light-emitting element 12a, and a second light-receiving element 12b are connected to the data processing circuit 2A. The functions of the ADC 26 and the switching circuit 27 in the data processing circuit 2A are similar to those of the ADC 26 and the switching circuit 27 in the first data processing circuit 2.

[0109] The control device 52A includes an ECU 7A. Similar to the ECU 7 in Fig. 4, the ECU 7A includes a CPU 71, a ROM 72, a RAM 73, an input / output buffer (not shown), and the like. Similar to the ECU 7 in Fig. 4, the ECU 7A is a computer that controls various systems in the vehicle 100. The ECU 7A is configured with an IC chip such as an ASIC.

[0110] Various data related to rain detection are transmitted and received between the rain detection device 51A and the control device 52A. Specifically, various data related to rain detection are transmitted and received between the data processing circuit 2A in the rain detection device 51A and the ECU 7A in the control device 52A. Therefore, the control device 52A is also a device equipped with functions related to rain detection. As a result, it can be said that the rain detection device 51A and the control device 52A constitute a rain detection system 50A.

[0111] As rain detection processing, the data processing circuit 2A basically executes processing similar to that executed by the first data processing circuit 2 in Fig. 4. The processing executed by the data processing circuit 2A differs from the processing executed by the first data processing circuit 2 in Fig. 4 in that, for example, the data processing circuit 2A does not determine a change in the state of infrared light or ultraviolet light, and does not output a signal such as an interrupt signal depending on the result of that determination.

[0112] In the rain detection system 50A, a control device 52A is provided with a nonvolatile memory 6 having the same function as the nonvolatile memory 4 in Fig. 4. The nonvolatile memory 6 stores infrared light determination data and ultraviolet light determination data similar to those of the nonvolatile memory 4 in Fig. 4.

[0113] The ECU 7A reads out the infrared light determination data and the ultraviolet light determination data from the nonvolatile memory 6 and stores the data in the RAM 73. The ECU 7A periodically reads out the first detection data (infrared light detection data) stored in the first register 24 of the data processing circuit 2A and the second detection data (ultraviolet light detection data) stored in the second register 25 of the data processing circuit 2A.

[0114] Then, the ECU 7A determines whether or not there has been a change in the state of infrared light from the reference state by comparing the first detection data with the infrared light determination data, similar to the second data processing circuit 3 in Fig. 4. Furthermore, the ECU 7A determines whether or not there has been a change in the state of ultraviolet light from the reference state by comparing the second detection data with the infrared light determination data, similar to the second data processing circuit 3 in Fig. 4.

[0115] When the ECU 7A determines that there has been a state change in the detection state of infrared light, and when it determines that there has been a state change in the detection state of ultraviolet light, it determines the type of state change regarding the detection state of infrared light and the detection state of ultraviolet light, similar to the second data processing circuit 3 of Figure 4.

[0116] When it is determined that there has been a change in the detection state of the first reflected light 14a, the ECU 7A determines the type of state change related to the detection state of infrared light by comparing the first detection data with the first threshold value and the second threshold value in the infrared light determination data. The method of determining the type of state change related to the detection state of infrared light is the same as the determination method executed by the second data processing circuit 3 in FIG.

[0117] When it is determined that there has been a change in the detection state of the second reflected light 15a, the ECU 7A determines the type of change in the state of ultraviolet light by comparing the second detection data with the third and fourth thresholds in the ultraviolet light determination data. The method for determining the type of change in the state of ultraviolet light detection is the same as the method executed by the second data processing circuit 3 in FIG. 4.

[0118] In this way, in the second embodiment, the control device 52A (ECU 7A) in the rain detection system 50A determines the type of state change related to the detection state of infrared light, and also functions as a determination device that determines the type of state change related to the detection state of ultraviolet light. Therefore, in the second embodiment, the control device 52A (ECU 7A) in the rain detection system 50A functions as a determination device that determines the abnormal state of the rain detection device 51A.

[0119] When the determination result of the type of state change is a state change from the rain detection state, the ECU 7A controls the wiper device provided on the vehicle 100. When the determination result of the type of state change is a state change to an abnormal state, the ECU 7A executes control to deal with the abnormal state.

[0120] [Wiper control and abnormality response control in rain detection device 51A] Next, the wiper control and abnormality response control of the rain detection system 50A of embodiment 2 will be described. Figures 9 and 10 are flowcharts showing the wiper control and abnormality response control of the rain detection system 50A of embodiment 2. Figures 9 and 10 show a series of flowcharts illustrating the controls executed in cooperation between the rain detection device 51A and the control device 52A.

[0121] 9 and 10 are executed by the CPU 21 of the data processing circuit 2A in the rain detection device 51A and the CPU 71 of the ECU 7 in the control device 52A. The process shown in Fig. 9 is executed once when the rain detection device 51A is started up. The process shown in Fig. 10 is executed repeatedly after the control executed when the rain detection device 51A is started up has ended.

[0122] 9, the process executed when the rain detection device 51A is started will be described. In the control device 52A, as shown in step S31, the ECU 7A sends an operation start command to the data processing circuit 2A of the rain detection device 51A. Then, in the control device 52A, as shown in step S32, the ECU 7A reads the infrared light determination data and the ultraviolet light determination data from the nonvolatile memory 6, stores the read infrared light determination data and the ultraviolet light determination data in the RAM 73, and ends the process.

[0123] Referring to Fig. 10, the processes of the rain detection device 51A and the control device 52A executed after the rain detection device 51A is started will be described. The processes related to rain detection using infrared light shown in steps S41 and S42 and the processes related to abnormal state detection using ultraviolet light shown in steps S43 and S44 are executed alternately and repeatedly at a fixed cycle. Therefore, when the series of processes shown in Fig. 10 is executed, if steps S41 and S42 are executed, steps S43 and S44 are not executed, and if steps S43 and S44 are executed, steps S41 and S42 are not executed. Switching between the processes related to rain detection using infrared light and the processes related to abnormal state detection using ultraviolet light is executed by the data processing circuit 2A controlling the switching circuit 27 shown in Fig. 5.

[0124] At the timing when steps S41 and S42 are executed, as shown in step S41, the data processing circuit 2A of the rain detection device 51A causes the first light-emitting element 11a to emit infrared light 14, and stores in the first register 24 the first detection data converted from the first detection signal output from the first light-receiving element 11b in accordance with the first reflected light 14a received by the first light-receiving element 11b.

[0125] At the timing when steps S41 and S42 are executed, as shown in step S42, the ECU 7A of the control device 52A accesses the data processing circuit 2A to read out the first detection data stored in the first register 24, compares the read-out first detection data with the infrared light determination data stored in the RAM 73 in step S32, determines whether or not there has been a state change for the infrared light from the reference state, and proceeds to step S45.

[0126] In step S42, if the first detection data is less than the first threshold value of the infrared light determination data, it is determined that there is no state change.In step S42, if the first detection data is equal to or greater than the first threshold value of the infrared light determination data, it is determined that there is a state change.

[0127] At the timing when steps S43 and S44 are executed, as shown in step S43, the data processing circuit 2A of the rain detection device 51A causes the second light-emitting element 12a to emit ultraviolet light 15, and stores in the second register 25 the second detection data converted from the second detection signal output from the second light-receiving element 12b in accordance with the second reflected light 15a received by the second light-receiving element 12b.

[0128] When steps S43 and S44 are executed, as shown in step S44, the ECU 7A of the control device 52A accesses the data processing circuit 2A to read the second detection data stored in the second register 25, compares the read second detection data with the ultraviolet light judgment data stored in the RAM 73 in step S32, determines whether or not there has been a state change from the reference state for the ultraviolet light, and proceeds to step S45.

[0129] In step S44, if the second detection data is greater than the third threshold and less than the fourth threshold, it is determined that there is no change in the detection state of the second reflected light 15a.In step S44, if the second detection data is equal to or less than the third threshold or equal to or greater than the fourth threshold, it is determined that there has been a change in the state of the ultraviolet light from the reference state.

[0130] As shown in step S45, ECU 7A of control device 52A determines whether it is determined in step S42 or step S44 that a state change has occurred in infrared light or ultraviolet light. Specifically, in step S45, in the cycle in which steps S41 and S42 are executed, it determines whether it is determined in step S42 that a state change has occurred in infrared light. In step S45, in the cycle in which steps S43 and S44 are executed, it determines whether it is determined in step S44 that a state change has occurred in ultraviolet light.

[0131] If it is determined in step S45 that no state change has occurred, the process ends. On the other hand, if it is determined in step S45 that a state change has occurred, the following process is performed as shown in step S46. In step S46, ECU 7A of control device 52A determines the type of state change based on the first detection data read out in S42 or the second detection data read out in S44, and obtains determination result data indicative of the determination result of the type of state change.

[0132] In step S46, if the determination target for the type of state change is infrared light in the first detection data, the ECU 7A reads infrared light determination data from the RAM 73 and compares the first detection data with the infrared light determination data to determine the type of state change.On the other hand, in step S46, if the determination target for the type of state change is ultraviolet light in the second detection data, the ECU 7A reads ultraviolet light determination data from the RAM 73 and compares the second detection data with the ultraviolet light determination data to determine the type of state change.

[0133] In step S46, for example, the following determination is made. If the first detection data is equal to or greater than the first threshold value of the infrared light determination data and less than the second threshold value, the ECU 7A determines that the type of state change is a state in which rain of a first rainfall amount (a relatively light rainfall amount) has been detected. If the first detection data is equal to or greater than the second threshold value of the infrared light determination data, the ECU 7A determines that the type of state change is a state in which rain of a second rainfall amount (a relatively heavy rainfall amount) has been detected. If the second detection data is equal to or less than the third threshold value of the ultraviolet light determination data or equal to or greater than the fourth threshold value, the ECU 7A determines that the type of state change is a state in which an abnormal state of the rain detection device 51A has been detected.

[0134] When the ECU 7A obtains the determination result data in step S46, the ECU 7A checks the determination result data for the type of state change, as shown in step S47. As shown in step S48, the ECU 7A determines whether the determination result data checked in step S47 is a determination result that an abnormal state of the rain detection device 51A has been detected.

[0135] In step S48, if it is determined that the determination result data is not a result of detecting an abnormal state of the rain detection device 51A, the determination result data is a result of detecting rain. In this case, as shown in step S49, the ECU 7A controls the wiper device provided on the vehicle 100 in accordance with the determination result data, and ends the process. In step S49, control similar to the control of the wiper device in step S20 described above is executed.

[0136] On the other hand, if it is determined in step S48 that the determination result data indicates that an abnormal state of the rain detection device 51A has been detected, the ECU 7A performs abnormality response control in accordance with the determination result data, as shown in step S50, and then ends the process. In step S50, control similar to the abnormality response control in step S21 described above is executed.

[0137] In the second embodiment described above, the determination of an abnormal state that is performed by the second data processing circuit 3 included in the rain detection device 51 in the first embodiment is performed by the ECU 7A included in the control device 52A in the rain detection system 50A. As a result, in the second embodiment, it is possible to obtain technical effects similar to those obtained in the first embodiment, such as improving the accuracy of detecting an abnormal state regarding rain detection using infrared light.

[0138] <Additional Notes> The present embodiment as described above includes the following technical idea.

[0139] [Configuration 1] A first light-emitting element (first light-emitting element 11a) that emits infrared light, a first light receiving element (first light receiving element 11b) that receives first reflected light corresponding to the infrared light emitted from the first light emitting element (first light emitting element 11a) and outputs a first detection signal; a second light-emitting element (second light-emitting element 12a) that emits ultraviolet light; a second light receiving element (second light receiving element 12b) that receives second reflected light corresponding to the ultraviolet light emitted from the second light emitting element (second light emitting element 12a) and outputs a second detection signal; a first data processing circuit (first data processing circuit 2) that converts the first detection signal into first detection data and performs first data processing (step S17, etc.) to detect rain according to the first detection data; a second data processing circuit (second data processing circuit 3) that performs second data processing (step S17, etc.) to determine whether or not an abnormal state has occurred in rain detection using infrared light emitted from the first light-emitting element (first light-emitting element 11a); The first data processing circuit (first data processing circuit 2) further converts the second detection signal into second detection data, The second data processing circuit (second data processing circuit 3) determines whether the abnormal state has occurred or not in the second data processing according to the second detection data (step S17, etc.), and is a rain detection device (rain detection device 51).

[0140] With this configuration, the second data processing circuit in the rain detection device determines whether or not an abnormal condition regarding rain detection has occurred using the second reflected light, which is ultraviolet light, thereby improving the accuracy of detecting an abnormal condition regarding rain detection using infrared light in environments that are susceptible to the influence of infrared light.

[0141] [Configuration 2] The device further includes a memory (non-volatile memory 4) that stores in advance determination data for determining whether or not the abnormal state has occurred based on the detection data of the second reflected light, The rain detection device (rain detection device 51) according to configuration 1, wherein the second data processing circuit (second data processing circuit 3) determines whether or not the abnormal state has occurred by comparing the judgment data with the second detection data in the second data processing.

[0142] According to this configuration, by comparing the judgment data for determining an abnormal state stored in the memory with the second detection data, which is the detection data of ultraviolet light detected by the second light receiving element, it is determined whether or not an abnormal state regarding rain detection has occurred, so that it is possible to determine whether or not an abnormal state regarding rain detection has occurred based on predetermined judgment data.

[0143] [Configuration 3] The first light-emitting element (first light-emitting element 11a), the first light-receiving element (first light-receiving element 11b), the second light-emitting element (second light-emitting element 12a), and the second light-receiving element (second light-receiving element 12b) can be arranged facing a triple-layer glass (front windshield 60) having an intermediate layer (intermediate layer 62) that suppresses transmission of ultraviolet light, The rain detection device (rain detection device 51) according to configuration 1 or 2, wherein the second reflected light received by the second light receiving element is ultraviolet light emitted from the second light emitting element (second light emitting element 12a) and reflected by the intermediate layer (intermediate layer 62).

[0144] With this configuration, the first light-emitting element, the first light-receiving element, the second light-emitting element, and the second light-receiving element can be arranged facing a triple-pane glass having an intermediate layer that suppresses the transmission of ultraviolet light.Therefore, detection of abnormal conditions related to rain detection is performed using ultraviolet light in an environment that is less susceptible to the influence of ultraviolet light from outside the triple-pane glass, thereby improving the detection accuracy of abnormal conditions related to rain detection.

[0145] [Configuration 4] A detection device (rain detection device 51) according to any one of configurations 1 to 3, wherein the abnormal state determined by the second data processing circuit (second data processing circuit 3) includes an electrical failure of the rain detection device (rain detection device 51).

[0146] With this configuration, abnormal conditions related to rain detection, including electrical failures, can be detected.

[0147] [Configuration 5] A rain detection device (rain detection device 51) according to any one of configurations 1 to 4, wherein the abnormal state determined by the second data processing circuit (second data processing circuit 3) includes a physical failure of the rain detection device (rain detection device 51).

[0148] With this configuration, it is possible to detect abnormal conditions related to rain detection, including physical failures.

[0149] [Configuration 6] A rain detector (rain detector 51A) that detects rain using infrared light; A determination device (control device 52A) for determining the rainfall state according to the detection data of the rain detection device is provided. The rain detection device (rain detection device 51A) a first light-emitting element (first light-emitting element 11a) that emits infrared light; a first light receiving element (first light receiving element 11b) that receives first reflected light corresponding to the infrared light emitted from the first light emitting element (first light emitting element 11a) and outputs a first detection signal; a second light-emitting element (second light-emitting element 12a) that emits ultraviolet light; a second light receiving element that receives second reflected light corresponding to the ultraviolet light emitted from the second light emitting element (second light emitting element 12a) and outputs a second detection signal; a first storage unit (first register 24); a second storage unit (second register 25); a conversion circuit (ADC 26) that converts the first detection signal into first detection data and stores the first detection data in the first storage unit (first register 24); The conversion circuit (ADC 26) further converts the second detection signal into second detection data and stores the second detection data in the second storage unit (second register 25); The determination device (control device 52A) First data processing (step S46, etc.) for detecting rain according to the first detection data stored in the first storage unit (first register 24); A rain detection system that executes second data processing (step S46, etc.) to determine whether or not an abnormal state has occurred in rain detection using infrared light emitted from the first light-emitting element (first light-emitting element 11a) based on the second detection data stored in the second memory unit (second register 25).

[0150] With this configuration, the determination device in the rain detection system determines whether or not an abnormal condition has occurred in rain detection using the second reflected light, which is ultraviolet light, thereby improving the accuracy of detecting an abnormal condition in rain detection using infrared light in environments that are susceptible to the influence of infrared light.

[0151] [Configuration 7] The determination device (control device 52A) The device further includes a memory (non-volatile memory 6) that stores in advance determination data for determining whether or not the abnormal state has occurred based on the detection data of the second reflected light, 7. The rain detection system according to configuration 6, wherein in the second data processing, the determination data is compared with the second detection data to determine whether or not the abnormal state has occurred.

[0152] According to this configuration, by comparing the judgment data for determining an abnormal state stored in the memory with the second detection data, which is the detection data of ultraviolet light detected by the second light receiving element, it is determined whether or not an abnormal state regarding rain detection has occurred, so that it is possible to determine whether or not an abnormal state regarding rain detection has occurred based on predetermined judgment data.

[0153] [Configuration 8] A step of emitting infrared light from a first light-emitting element (first light-emitting element 11a) (steps S11 and S41); a step of converting a first detection signal output from a first light receiving element (first light receiving element 11b) that receives first reflected light corresponding to the infrared light emitted from the first light emitting element (first light emitting element 11a) into first detection data (steps S11 and S41); a step of emitting ultraviolet light from the second light-emitting element (second light-emitting element 12a) (steps S13 and S43); a step of converting a second detection signal output from a second light receiving element (second light receiving element 12b) that receives second reflected light corresponding to the ultraviolet light emitted from the second light emitting element (second light emitting element 12a) into second detection data (steps S13 and S43); a step of performing first data processing to detect rain according to the first detection data (steps S17 and S46); A rain detection method comprising a step (steps S17, S46) of performing second data processing to determine whether or not an abnormal state has occurred in rain detection using infrared light emitted from the first light-emitting element (first light-emitting element 11a) based on the second detection data.

[0154] With this configuration, the rain detection device 51 determines whether or not an abnormal condition has occurred in rain detection using the second reflected light, which is ultraviolet light, thereby improving the accuracy of detecting an abnormal condition in rain detection using infrared light in environments that are susceptible to the influence of infrared light.

[0155] [Configuration 9] The rain detection method according to Configuration 8, wherein the second data processing determines whether the abnormal state has occurred by comparing the second detection data with determination data for determining whether the abnormal state has occurred based on the detection data of the second reflected light (steps S17, S46).

[0156] According to this configuration, by comparing the judgment data for determining an abnormal state stored in the memory with the second detection data, which is the detection data of ultraviolet light detected by the second light receiving element, it is determined whether or not an abnormal state regarding rain detection has occurred, so that it is possible to determine whether or not an abnormal state regarding rain detection has occurred based on predetermined judgment data.

[0157] [Configuration 10] The first light-emitting element (first light-emitting element 11a), the first light-receiving element (first light-receiving element 11b), the second light-emitting element (second light-emitting element 12a), and the second light-receiving element (second light-receiving element 12b) can be arranged facing a triple-layer glass (front windshield 60) having an intermediate layer (intermediate layer 62) that suppresses transmission of ultraviolet light, The rain detection method according to configuration 8 or 9, wherein the second reflected light received by the second light receiving element (second light receiving element 12b) is ultraviolet light emitted from the second light emitting element (second light emitting element 12a) and reflected by the intermediate layer (intermediate layer 62).

[0158] With this configuration, the first light-emitting element, the first light-receiving element, the second light-emitting element, and the second light-receiving element can be arranged facing a triple-pane glass having an intermediate layer that suppresses the transmission of ultraviolet light.Therefore, detection of abnormal conditions related to rain detection is performed using ultraviolet light in an environment that is less susceptible to the influence of ultraviolet light from outside the triple-pane glass, thereby improving the detection accuracy of abnormal conditions related to rain detection.

[0159] [Configuration 11] The rain detection method according to any one of Configurations 8 to 10, wherein the abnormal state determined by the second data processing includes an electrical failure of a rain detection device (rain detection device 51, 51A) in which the first light-emitting element (first light-emitting element 11a), the first light-receiving element (first light-receiving element 11b), the second light-emitting element (second light-emitting element 12a), and the second light-receiving element (second light-receiving element 12b) are provided.

[0160] With this configuration, abnormal conditions related to rain detection, including electrical failures, can be detected.

[0161] [Configuration 12] The rain detection method according to any one of Configurations 8 to 11, wherein the abnormal state determined by the second data processing includes a physical failure of the rain detection device (rain detection device 51, 51A) in which the first light-emitting element (first light-emitting element 11a), the first light-receiving element (first light-receiving element 11b), the second light-emitting element (second light-emitting element 12a), and the second light-receiving element (second light-receiving element 12b) are provided.

[0162] With this configuration, it is possible to detect abnormal conditions related to rain detection, including physical failures.

[0163] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is defined by the claims, not by the description of the above embodiments, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0164] 11a First light-emitting element, 11b First light-receiving element, 12a Second light-emitting element, 12b Second light-receiving element, 2 First data processing circuit, 3 Second data processing circuit, 51, 51A Rain detection device, 4, 6 Non-volatile memory, 62 Intermediate layer, 60 Front window, 24 First register, 25 Second register.

Claims

1. a first light-emitting element that emits infrared light; a first light receiving element that receives first reflected light corresponding to the infrared light emitted from the first light emitting element and outputs a first detection signal; a second light-emitting element that emits ultraviolet light; a second light receiving element that receives second reflected light corresponding to the ultraviolet light emitted from the second light emitting element and outputs a second detection signal; a first data processing circuit that converts the first detection signal into first detection data and performs first data processing to detect rain according to the first detection data; a second data processing circuit that performs second data processing to determine whether an abnormal state has occurred in relation to rain detection using the infrared light emitted from the first light-emitting element; The first data processing circuit further converts the second detection signal into second detection data; The second data processing circuit determines whether the abnormal state has occurred in accordance with the second detection data in the second data processing.

2. a memory that stores in advance determination data for determining whether or not the abnormal state has occurred based on the detection data of the second reflected light; 2. The rain detection device according to claim 1, wherein the second data processing circuit determines whether the abnormal state has occurred by comparing the determination data with the second detection data in the second data processing.

3. the first light-emitting element, the first light-receiving element, the second light-emitting element, and the second light-receiving element can be arranged facing a triple-layer glass having an intermediate layer that suppresses transmission of ultraviolet light, 3. The rain detection device according to claim 1, wherein the second reflected light received by the second light receiving element is ultraviolet light emitted from the second light emitting element and reflected by the intermediate layer.

4. 3. The rain detection device according to claim 1, wherein the abnormal state determined by the second data processing circuit includes an electrical failure of the rain detection device.

5. 3. The rain detection device according to claim 1, wherein the abnormal state determined by the second data processing circuit includes a physical failure of the rain detection device.

6. a rain detection device that detects rain using infrared light; a determination device for determining a rainfall state based on the detection data of the rain detection device; The rain detection device is a first light-emitting element that emits infrared light; a first light receiving element that receives first reflected light corresponding to the infrared light emitted from the first light emitting element and outputs a first detection signal; a second light-emitting element that emits ultraviolet light; a second light receiving element that receives second reflected light corresponding to the ultraviolet light emitted from the second light emitting element and outputs a second detection signal; a first storage unit; A second storage unit; a conversion circuit that converts the first detection signal into first detection data and stores the first detection data in the first storage unit; The conversion circuit further converts the second detection signal into second detection data and stores the second detection data in the second storage unit; The determination device a first data processing for detecting rain according to the first detection data stored in the first storage unit; and second data processing that determines whether an abnormal state has occurred in relation to rain detection using infrared light emitted from the first light-emitting element, based on the second detection data stored in the second memory unit.

7. The determination device a memory that stores in advance determination data for determining whether or not the abnormal state has occurred based on the detection data of the second reflected light; The rain detection system according to claim 6 , wherein in the second data processing, the determination data is compared with the second detection data to determine whether or not the abnormal state has occurred.

8. Emitting infrared light from a first light-emitting element; converting a first detection signal output from a first light receiving element that receives first reflected light corresponding to the infrared light emitted from the first light emitting element into first detection data; Emitting ultraviolet light from the second light-emitting element; converting a second detection signal output from a second light receiving element that receives second reflected light corresponding to the ultraviolet light emitted from the second light emitting element into second detection data; performing first data processing to detect rain according to the first detection data; and performing second data processing to determine whether an abnormal state has occurred in relation to rain detection using infrared light emitted from the first light-emitting element based on the second detection data.

9. 9. The rain detection method according to claim 8, wherein the second data processing determines whether the abnormal state has occurred by comparing determination data for determining whether the abnormal state has occurred based on detection data of the second reflected light with the second detection data.

10. the first light-emitting element, the first light-receiving element, the second light-emitting element, and the second light-receiving element can be arranged facing a triple-layer glass having an intermediate layer that suppresses transmission of ultraviolet light, 10. The rain detection method according to claim 8, wherein the second reflected light received by the second light receiving element is ultraviolet light emitted from the second light emitting element and reflected by the intermediate layer.

11. 10. The rain detection method according to claim 8, wherein the abnormal state determined by the second data processing includes an electrical failure of the first light-emitting element, the first light-receiving element, the second light-emitting element, and a rain detection device provided with the second light-receiving element.

12. 10. The rain detection method according to claim 8, wherein the abnormal state determined by the second data processing includes a physical failure of the first light-emitting element, the first light-receiving element, the second light-emitting element, and a rain detection device in which the second light-receiving element is provided.

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