Optical structure of an optical rain sensor and rainfall detection method

Abstract

The present invention relates to a technical field, and specifically to an optical structure and rainfall detection method of an optical rain sensor, which is used for sensing rainfall on a vehicle windshield. The optical structure includes a support base, a light emitting component, and a light receiving component. The light emitting component and the light receiving component are arranged on the support base. The light emitting component includes a plurality of light sources and a plurality of transmitting end lenses. The light receiving component includes a light detector and a light guiding structure. The light guiding structure includes a plurality of groups of light guiding components. The light beam passes through the transmitting end lens, the vehicle windshield, and the light guiding structure in sequence and is received by the light detector. The present invention adopts a multi-channel optical path system to obtain more signals, and can use an algorithm to filter and process the signals to improve the signal-to-noise ratio and improve the accuracy of detection. The light receiving component of the present invention adopts a light guiding structure to replace the lens focusing in the prior art, so that the light beam is incident on the light detector from different directions, without the need to design a separate lens for each channel.

Description

Technical Field

[0001] The present invention relates to the technical field of rain sensors, and in particular to an optical structure of an optical rain sensor and a rain detection method. Background Art

[0002] With the continuous development and progress of science and technology, subways, light rails, motor vehicles and other vehicles have begun to be equipped with automatic wiper systems with automatic rain detection. The core component of this system is the rain sensor.

[0003] Optical rain sensors generally use the principle of total internal reflection (TRIR) to sense raindrop size and automatically adjust wiper speed. An optical rain sensor contains a light source that emits a beam of light through the windshield. When the windshield is clear, the beam is totally reflected by the outer surface and reaches the corresponding optical sensor. However, when rain falls, the rain prevents the beam from being totally reflected, causing the light path to deviate. This changes the amount of light received by the sensor, thereby detecting the presence of rain.

[0004] The larger the spot area used by optical sensors to detect rainfall, the higher the signal-to-noise ratio (SNR), resulting in more detailed and accurate information. Therefore, to facilitate algorithm processing and achieve a high SNR, multi-channel, coarse-beam optical systems are the preferred optical design direction. However, due to the demand for miniaturization of rainfall sensors and strict size restrictions, the available space for the optical system is limited, significantly restricting the optical structure design. Summary of the Invention

[0005] The object of the present invention is to solve at least one of the technical problems existing in the prior art and to provide an optical structure of an optical rain sensor and a rain detection method.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is as follows: an optical structure of an optical rain sensor, used for sensing rain on a vehicle windshield, comprising a support base, a light emitting assembly and a light receiving assembly, the light emitting assembly and the light receiving assembly being arranged on the support base, the light emitting assembly comprising a plurality of light sources and a plurality of transmitting end lenses, one light source and one transmitting end lens forming a group of light emitters, the light receiving assembly being located at the center of the support base, the plurality of light sources and transmitting end lenses being evenly distributed around the light receiving assembly, the light receiving assembly comprising a light detector and a light guiding structure, the light guiding structure comprising a plurality of groups of light guiding assemblies, a group of the light guiding assemblies corresponding to a group of light emitters, the light source emitting a light beam, the light beam passing through the transmitting end lens, the vehicle windshield, and the light guiding structure in sequence and being received by the light detector, the transmitting end lens being used to collimate the light beam emitted by the light source, and the light guiding structure being used to transmit the light beam to the light detector.

[0007] Furthermore, the support base is a round box-shaped high-infrared-transmittance silicone block, and the light emitting component and the light receiving component are arranged in the high-infrared-transmittance silicone block.

[0008] Furthermore, the support base is bonded to the vehicle windshield.

[0009] Furthermore, the light guide assembly includes one light guide plate or multiple light guide plates arranged in parallel.

[0010] Furthermore, the light guide plate includes an incident surface, an exit surface and two reflective surfaces. The light beam enters the light guide assembly through the incident surface at a certain angle, is reflected multiple times by the two reflective surfaces, reaches the exit surface, and is refracted onto the light detector through the exit surface.

[0011] Furthermore, the incident surface is bonded to the support base, the two reflecting surfaces are parallel to each other and perpendicular to the incident surface, and the emitting surface and the reflecting surface form a certain refraction tilt angle.

[0012] Furthermore, the light detector includes a detection surface, and the detection surface is capable of receiving all light passing through the light guiding structure.

[0013] Furthermore, the light guide components are arranged in a circle with the central axis of the light detector as the center to form a regular polygonal structure, and the light emitter is arranged on the outside of the corresponding light guide component.

[0014] Furthermore, the emission end lens is a TIR lens, and an optical pattern is provided on the total reflection surface of the TIR lens.

[0015] Furthermore, it also includes a controller, which is connected to the light source and the light detector respectively and controls the light source and the light detector.

[0016] The present invention also provides a method for detecting rainfall using an optical rainfall sensor, comprising the following steps:

[0017] Step 1: Turn on one of the light sources and send a beam of light to the transmitting end lens;

[0018] Step 2: The light beam is collimated by the transmitting end lens and directed to the vehicle windshield;

[0019] Step 3: When there is no rain on the vehicle windshield, the light beam is totally reflected by the outer surface of the vehicle windshield and reaches the light receiving component to be received. When there is rain on the vehicle windshield, the rain on the windshield causes the light beam to be unable to be totally reflected, the light path deviates, and the light cannot reach the light receiving component.

[0020] Step 4: Turn on the remaining light sources in sequence to complete steps 1-3, and automatically adjust the operating speed of the wiper through all the information received by the light receiving component.

[0021] As can be seen from the above description of the present invention, compared with the prior art, the optical structure of the optical rain sensor of the present invention has at least one of the following beneficial effects:

[0022] The optical rain gauge of the present invention comprises a multi-channel optical system composed of a plurality of light sources and a plurality of transmitting end lenses. The multi-channel optical system is used to obtain more signals, and an algorithm can be used to filter and process the signals to improve the signal-to-noise ratio and enhance the detection accuracy.

[0023] The optical rain sensor's light receiving assembly uses a light-guiding structure to replace the lens focusing method used in the prior art, allowing light beams to enter the light detector from different directions. This eliminates the need for a separate lens for each channel. The light beams can be received by the light detector simply by being guided into the light guide plate. This maximizes the detection spot area and improves the signal-to-noise ratio while meeting the miniaturization requirements of the rain sensor.

[0024] The optical rain gauge of the present invention adopts a TIR lens as the transmitting end lens, and adds an optical pattern on the total reflection surface to realize light beam collimation while controlling the light direction in different regions, so that a large area of ​​light spot can be received by the detector.

[0025] The rainfall detection method of the optical rain sensor of the present invention utilizes a multi-channel optical path system to obtain more signals, and all signals are received by only one light detector, which facilitates the algorithm to perform signal comparison processing, improves detection accuracy, meets miniaturization requirements, and reduces manufacturing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the optical structure of an optical rain sensor in a preferred embodiment of the present invention;

[0027] Figure 2 A schematic structural diagram of a light receiving assembly in a preferred embodiment of the present invention;

[0028] Figure 3 Schematic diagram of the structure of the emitting end lens in a preferred embodiment of the present invention;

[0029] Figure numerals: 1. Support base; 2. Light emitting component; 3. Light receiving component; 21. Light source; 22. Transmitting end lens; 23. Optical pattern; 31. Light detector; 32. Light guide structure; 33. Light guide plate; 331. Incident surface; 332. Exit surface; 333. Reflection surface. DETAILED DESCRIPTION

[0030] The technical solutions of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0031] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "connected" and "connection" should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integral connection; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediary. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0032] Reference Figure 1-3 As shown, a preferred embodiment of the present invention is an optical structure of an optical rain sensor for sensing rain on a vehicle windshield, comprising a support base 1, a light emitting component 2 and a light receiving component 3, wherein the light emitting component 2 and the light receiving component 3 are arranged on the support base 1, the light emitting component 2 comprises a plurality of light sources 21 and a plurality of transmitting end lenses 22, one light source 21 and one transmitting end lens 22 constitute a group of light emitters, the light receiving component 3 is located at the center of the support base 1, and a plurality of the light sources 21 and the transmitting end lenses 22 are evenly distributed around the light receiving component 3, the light receiving component 3 comprises a light detector 31 and a light guiding structure 32, the light guiding structure 32 comprises a plurality of groups of light guiding components, a group of the light guiding components corresponds to a group of light emitters, the light source 21 emits a light beam, and the light beam passes through the transmitting end lens 22, the vehicle windshield, and the light guiding structure 32 in sequence and is received by the light detector 31, the transmitting end lens 22 is used to collimate the light beam emitted by the light source 21, and the light guiding structure 32 is used to conduct the light beam to the light detector 31.

[0033] The optical rain sensor of the present invention is composed of a multi-channel optical path system consisting of several light sources 21 and several transmitting end lenses 22. The multi-channel optical path system is used to obtain more signals, and the signals can be screened and processed by algorithms to improve the signal-to-noise ratio and the accuracy of detection. The light receiving component 3 of the optical rain sensor of the present invention adopts a light guiding structure 32 to replace the lens focusing in the prior art, so that the light beam is incident on the light detector 31 from different directions. There is no need to design a separate lens for each channel. The light beam only needs to be guided into the light guide plate to be received by the light detector 31. While meeting the miniaturization requirements of the rain sensor, the detection spot area is increased as much as possible to improve the signal-to-noise ratio. The transmitting end lens 22 of the optical rain sensor of the present invention adopts a TIR lens, and an optical pattern 23 is added on the total reflection surface to achieve light beam collimation while locally controlling the light direction in different areas, so that a large area of ​​light spot can be received by the detector.

[0034] As a preferred embodiment of the present invention, it may also have the following additional technical features:

[0035] In this embodiment, the support base 1 is a circular box-shaped, high-infrared-transmittance silicone block, within which the light emitting assembly 2 and light receiving assembly 3 are mounted. The circular box-shaped, high-infrared-transmittance silicone block secures the light emitting assembly 2 and light receiving assembly 3. The high-infrared-transmittance silicone block 12 filters out other types of light, retaining infrared light with strong penetrating power. This is then paired with a light detector 31 for infrared light detection, ensuring detection sensitivity and improving measurement accuracy.

[0036] In this embodiment, the support base 1 is bonded to the vehicle windshield. By bonding the support base 1 to the vehicle windshield, the light emitting component 2 and the light receiving component 3 are fixed to the vehicle windshield to perform rainfall detection.

[0037] In this embodiment, the light guide assembly includes one light guide plate 33 or multiple parallel light guide plates 33. Using one or more parallel light guide plates 33 in a light guide assembly can increase the detected light spot area, broaden the detection range of the vehicle windshield, improve the signal-to-noise ratio, and enhance detection accuracy. Specifically, two parallel light guide plates 33 are used in this embodiment. Furthermore, using light guide plates 33 to guide light eliminates the need for designing a separate lens for each channel, reducing design and manufacturing complexity.

[0038] In this embodiment, the light guide plate 33 includes an incident surface 331, an exit surface 332, and two reflective surfaces 333. The light beam enters the light guide assembly at a certain angle through the incident surface 331, is reflected multiple times by the two reflective surfaces 333, and reaches the exit surface 332. It is then refracted by the exit surface 332 and reaches the light detector 31. The incident surface 331 is bonded to the support base 1. The two reflective surfaces 333 are parallel to each other and perpendicular to the incident surface 331. The exit surface 332 and the reflective surfaces 333 form a certain refractive inclination angle. The light source 21 emits a light beam, which is collimated by the transmitting end lens 22 and then illuminates the vehicle windshield. When there is no rain on the vehicle windshield, the light beam undergoes total internal reflection on the outer surface of the vehicle windshield. The reflected light beam then enters the light guide assembly at a certain angle through the incident surface 331. The light beam is continuously reflected between the two parallel reflective surfaces 333 before being refracted by the exit surface 332 and reaches the light detector 31, where it is received by the light detector 31.

[0039] In this embodiment, the light detector 31 includes a detection surface that can receive all light passing through the light guide structure 32. The position and size of the detection surface are determined based on the refraction inclination angles of all the exit surfaces 332 to ensure that all light beams entering the light guide assembly are received by the light detector 31, thereby avoiding detection errors.

[0040] In this embodiment, the light guide assemblies are arranged in a circle around the central axis of the light detector 31 to form a regular polygonal structure. The light emitters are located outside the corresponding light guide assemblies. The light guide assemblies and their corresponding light emitters are arranged in a circle around the central axis of the light detector 31 so that the light beams generated by all light guide assemblies and light emitters can be received by the central light detector 31. This reduces the overall structure volume and meets miniaturization requirements. Multi-channel optical systems share a single light detector 31, saving materials and costs.

[0041] In this embodiment, the transmitting end lens 22 is a TIR lens, and an optical pattern 23 is provided on the total reflection surface of the TIR lens. TIR refers to "Total Internal Reflection", that is, total internal reflection, also known as total reflection, which is an optical phenomenon. When light enters a medium with a higher refractive index from a medium with a lower refractive index, if the angle of incidence is greater than a certain critical angle, the refracted light will disappear, and all the incident light will be reflected without entering the medium with a low refractive index. The TIR lens can improve the utilization rate of light energy. The TIR lens collects and processes light using the principle of total reflection. The transmitting end lens 22 uses a TIR lens with a good collimation effect. The addition of the optical pattern 23 on the total reflection surface can achieve light beam collimation while locally controlling the direction of the light in different regions, so that a large area of ​​light spot can be received by the detector, thereby improving detection accuracy.

[0042] In this embodiment, a controller is further included, which is connected to the light source 21 and the light detector 31 respectively and controls the light source 21 and the light detector 31. The rain sensor of the present invention meets the requirements of intelligent automation. The controller is used to control the light source 21 and the light detector 31 respectively, thereby realizing automated detection and being easy to use. The controller includes but is not limited to a small programmable processor.

[0043] The present invention also provides a method for detecting rainfall using an optical rainfall sensor, comprising the following steps:

[0044] Step 1: First, turn on one of the light sources 21, and the light source 21 emits a light beam to the transmitting end lens 22;

[0045] Step 2: The light beam is collimated by the transmitting end lens 22 and directed to the vehicle windshield;

[0046] Step 3: When there is no rain on the vehicle windshield, the light beam is totally reflected by the outer surface of the vehicle windshield and reaches the light receiving component 3 to be received. When there is rain on the vehicle windshield, the rain on the windshield causes the light beam to be unable to be totally reflected, the light path deviates, and the light beam cannot reach the light receiving component 3.

[0047] Step 4: Turn on the remaining light sources 21 in sequence to complete steps 1-3, and automatically adjust the operating speed of the wiper through all the information received by the light receiving component 3.

[0048] The controller turns on the light sources 21 in sequence to avoid mutual interference of the light beams generated by the light sources 21. By utilizing the signal difference between rain and no rain, the light receiving component 3 determines the amount of rain after receiving all signals, and then automatically adjusts the operating speed of the wiper.

[0049] The rainfall detection method of the optical rain sensor of the present invention utilizes a multi-channel optical path system to obtain more signals, and all signals are received by only one light detector 31, which facilitates the algorithm to perform signal comparison processing, improves detection accuracy, meets miniaturization requirements, and reduces manufacturing costs.

[0050] Under the premise that no conflict occurs, those skilled in the art may freely combine and superimpose the above-mentioned additional technical features.

[0051] It will be understood that the present invention is described by way of some embodiments, and it will be appreciated by those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present invention. In addition, under the teachings of the present invention, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of this application are intended to be protected by the present invention.

Claims

1. An optical structure of an optical rain sensor for sensing rain on a vehicle windshield, characterized in that: The invention comprises a support base (1), a light emitting assembly (2) and a light receiving assembly (3), wherein the light emitting assembly (2) and the light receiving assembly (3) are arranged on the support base (1), the light emitting assembly (2) comprises a plurality of light sources (21) and a plurality of transmitting end lenses (22), one light source (21) and one transmitting end lens (22) form a group of light emitters, the light receiving assembly (3) is located at the center of the support base (1), and the plurality of light sources (21) and the transmitting end lenses (22) are evenly distributed around the light receiving assembly (3). The light receiving assembly (3) comprises a light detector (31) and a light guide structure (32). The light guide structure (32) comprises a plurality of groups of light guide assemblies, one group of light guide assemblies corresponds to a group of light emitters. The light source (21) emits a light beam, which passes through the emission end lens (22), the vehicle windshield, and the light guide structure (32) in sequence and is received by the light detector (31). The emission end lens (22) is used to collimate the light beam emitted by the light source (21), and the light guide structure (32) is used to conduct the light beam to the light detector (31). The light guide assembly comprises a light guide plate (33) or a plurality of light guide plates (33) arranged in parallel; The light guide plate (33) comprises an incident surface (331), an exit surface (332) and two reflection surfaces (333). The light beam enters the light guide assembly through the incident surface (331) at a certain angle, is reflected multiple times by the two reflection surfaces (333) and reaches the exit surface (332), and is refracted by the exit surface (332) to the light detector (31).

2. The optical structure of an optical rain sensor according to claim 1, characterized in that: The support seat (1) is a round box-shaped high-infrared-transmittance silicone block, and the light-emitting component (2) and the light-receiving component (3) are arranged in the high-infrared-transmittance silicone block.

3. The optical structure of an optical rain sensor according to claim 1, characterized in that: The support seat (1) is bonded to the vehicle windshield.

4. The optical structure of an optical rain sensor according to claim 1, characterized in that: The incident surface (331) is bonded to the support seat (1), the two reflecting surfaces (333) are parallel to each other and perpendicular to the incident surface (331), and the emitting surface (332) and the reflecting surface (333) form a certain refraction tilt angle.

5. The optical structure of an optical rain sensor according to claim 1, characterized in that: The light detector (31) comprises a detection surface capable of receiving all light passing through the light-guiding structure (32).

6. The optical structure of an optical rain sensor according to claim 1, characterized in that: The light guide assembly is arranged around the central axis of the light detector (31) to form a regular polygonal structure, and the light emitter is arranged outside the corresponding light guide assembly.

7. The optical structure of an optical rain sensor according to claim 1, characterized in that: The emission end lens (22) is a TIR lens, and an optical pattern (23) is provided on the total reflection surface of the TIR lens.

8. The optical structure of an optical rain sensor according to claim 1, characterized in that: The device also includes a controller, which is connected to the light source (21) and the light detector (31) respectively and controls the light source (21) and the light detector (31).

9. A method for detecting rainfall using an optical rain sensor, characterized in that: Using the optical structure of an optical rain sensor according to any one of claims 1 to 8, the rain detection method comprises the following steps: Step 1: First, turn on one of the light sources (21), and the light source (21) emits a light beam toward the transmitting end lens (22); Step 2, the light beam is collimated by the emission end lens (22) and directed to the vehicle windshield; Step 3, when there is no rain on the vehicle windshield, the light beam is totally reflected on the outer surface of the vehicle windshield and reaches the light receiving component (3) to be received; when there is rain on the vehicle windshield, the rain on the windshield causes the light beam to be unable to be totally reflected, the light path deviates, and the light beam cannot reach the light receiving component (3); Step 4, turning on the remaining light sources (21) in sequence to complete steps 1-3, and automatically adjusting the operating speed of the wiper through all the information received by the light receiving component (3).

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