CN116106991A - Rainfall sensor - Google Patents

Abstract

The invention provides a rainfall sensor, which comprises a light source emitter, a sensor module and a sensor module, wherein the light source emitter is used for emitting light; the emitting end lens is provided with a preset distance from the light source emitter, and comprises a main convex lens and at least one sub convex lens arranged on one side of the main convex lens, wherein the focus of the main convex lens and the focus of the at least one sub convex lens are overlapped with the light emitting center of the light source emitter, and the main convex lens and the at least one sub convex lens are used for collecting light emitted by the light source emitter and refracting the light emitted by the light source emitter to form parallel light which is emitted at a certain angle with the horizontal direction; a glass for totally reflecting the light emitted from the emission end lens, the region of the glass subjected to total reflection being formed as a sensing region; a receiving end lens for focusing light totally reflected by the glass; and the photosensitive element is used for receiving the light focused by the receiving end lens. The invention effectively improves the detection area, enhances the rain sensitivity and reliability, and has lower cost, small volume and higher cost performance.

Description

Rainfall sensor

Technical Field

The invention relates to an automobile sensor, in particular to a rainfall sensor.

Background

Along with the improvement of the intelligent level of the automobile, the assembly rate of the vehicle-mounted rainfall sensor is also rapidly improved, and meanwhile, due to the increase of users, the requirements of automobile factories and users on the functions of automatic wipers are higher and higher, so that whether market acceptance can be continuously obtained is the current cost performance of the rainfall sensor is a very critical factor.

The rain sensor in the present stage basically utilizes the basic principle that infrared light is incident to the photophobic substance from the photophobic substance, and total reflection occurs when the incident angle is larger than the critical angle to carry out rain sensing design. When water drops fall in a detection area of the rainfall sensor, partial infrared light is refracted due to the difference of refractive indexes of water and air, reflected infrared light is reduced, the change amount and the change frequency of the infrared light are calculated through photoelectric induction and a software algorithm, so that the size of the rainfall is judged, and finally the scraping speed and the scraping frequency of the windscreen wiper are controlled according to the size of the rainfall.

At present, in order to obtain better rain sensitivity, most rain sensors form a multi-rain-sensing channel through two-transmission two-reception, three-transmission two-reception and other designs so as to enhance the rain sensitivity and the rain-sensing probability of the sensor.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide a rain sensor that can increase the collection rate of infrared light emitted from an infrared light source, and increase the area of a sensing area on glass, so as to solve the problems of high manufacturing cost and large volume caused by the rain sensor in the prior art for improving the sensitivity and reliability of sensing rain.

To achieve the above and other related objects, the present invention provides a rain sensor including a light source emitter for emitting light; the emitting end lens is provided with a preset distance from the light source emitter, and comprises a main convex lens and at least one sub-convex lens arranged on one side of the main convex lens, wherein the focus of the main convex lens and the focus of the at least one sub-convex lens are overlapped with the light emitting center of the light source emitter, and the main convex lens and the at least one sub-convex lens are used for collecting light emitted by the light source emitter and refracting the light emitted by the light source emitter to form parallel light which is emitted in a certain angle with the horizontal direction; a glass for totally reflecting light emitted from the main convex lens and the at least one sub-lens, thereby forming a sensing region in a region where the glass totally reflects; a receiving end lens for focusing the light totally reflected by the glass; and the photosensitive element is used for receiving the light focused by the receiving end lens.

Preferably, transparent jelly is filled between the glass and the transmitting end lens and between the glass and the receiving end lens, and the refractive indexes of the transparent jelly and the glass, the transmitting end lens and the receiving end lens are similar.

Preferably, the transmitting end lens and the receiving end lens are integrally designed.

Preferably, two sub-convex lenses are provided, and the two sub-convex lenses are tooth-shaped.

Preferably, the distance between the tooth tips of the two sub convex lenses is 2mm.

Preferably, the light source emitter comprises an LED infrared light source.

Preferably, the main convex lens is made of polycarbonate.

Preferably, the number of the light source emitters is two, the number of the emission end lenses is two, the number of the receiving end lenses is two, and the number of the photosensitive elements is one, wherein the two light source emitters are in one-to-one correspondence with the two emission end lenses, the two receiving end lenses are connected into a whole, the focuses of the two receiving end lenses are overlapped with the light receiving points of the photosensitive elements, and an included angle formed by the two receiving end lenses is defined as alpha, and the included angle is more than or equal to 50 and less than or equal to 180 degrees.

Preferably, said α is 60 °.

As described above, the rainfall sensor of the present invention has the following advantageous effects: according to the rainfall sensor, at least one sub-convex lens is additionally arranged in the convex lens at the transmitting end, namely, at least one refraction surface is additionally arranged, so that light emitted by the light source emitter is comprehensively collected, light emitted by the light source emitter penetrates through the newly-arranged refraction surface (sub-convex lens) to be refracted, and then is converged with light refracted by the main convex lens to be emitted to the glass, so that the area of a sensing area formed on the glass is larger, the area of the rainfall sensor detected by the glass is larger, and the rainfall sensitivity and reliability of the single rainfall sensor are effectively improved. Therefore, compared with the prior art, the rainfall sensor can effectively improve the detection area on glass on the premise of not arranging more photosensitive devices and sampling chips, further enhance the sensitivity and reliability of rain sensing, and has the advantages of lower cost, small volume and higher cost performance.

Drawings

Fig. 1 is a schematic diagram of the working principle of the rainfall sensor provided by the invention.

Fig. 2 is a schematic structural diagram of a transmitting lens and a receiving lens according to the present invention.

Fig. 3 is a schematic diagram of a structure of the rainfall sensor provided by the invention.

Fig. 4 is a schematic diagram of the rainfall sensor provided by the invention in operation.

Reference numerals illustrate:

10. light source emitter

20. Transmitting end lens

21. Main convex lens

22. Sub convex lens

30. Glass

40. Receiving end lens

50. Photosensitive element

60. Transparent jelly

101. First light source emitter

102. Second light source emitter

201. First transmitting end lens

202. Second transmitting end lens

401. First receiving end lens

402. Second receiving end lens

Detailed Description

Other advantages and effects of the present invention will become apparent to those skilled in the art from the following disclosure, which describes the embodiments of the present invention with reference to specific examples. The invention may be practiced or carried out in other embodiments that depart from the specific details, and the details of the present description may be modified or varied from the spirit and scope of the present invention.

The structure, proportion, size, etc. of the drawings are only used in conjunction with the disclosure of the specification to be understood and read by those skilled in the art, and are not limited to the practical conditions of the invention, so that any modification of structure, change of proportion or adjustment of size should not have any technical significance, and all fall within the coverage of the disclosure of the present invention without affecting the efficacy and achievement of the present invention. Meanwhile, the terms such as "front", "rear", "left", "right", "middle" and "first", "second" and the like are also used in the present specification for convenience of description, and are not intended to limit the scope of the present invention, but rather to change or adjust the relative relationship thereof without substantially changing the technical content, and are considered as the scope of the present invention.

In the description of the present invention, unless specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly coupled, detachably coupled, integrally connected, mechanically coupled, electrically coupled, directly coupled, or coupled via an intermediate medium, or in communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

Please refer to fig. 1 to 4. It should be noted that, the illustrations provided in the present embodiment merely illustrate the basic concept of the present invention by way of illustration, and only the components related to the present invention are shown in the drawings and are not drawn according to the number, shape and size of the components in actual implementation, and the form, number and proportion of the components in actual implementation may be arbitrarily changed, and the layout of the components may be more complex.

As shown in fig. 1 in particular, the present invention provides a rain sensor, which includes a light source emitter 10, a transmitting-end lens 20, a glass 30, a receiving-end lens 40, and a photosensitive element 50, wherein the light source emitter 10 is configured to emit light; the emitting end lens 20 has a preset distance from the light source emitter 10, and the emitting end lens 20 comprises a main convex lens 21 and at least one sub convex lens 22 arranged on one side of the main convex lens 21, wherein the focus of the main convex lens 21 and the focus of the at least one sub convex lens 22 are coincident with the light emitting center of the light source emitter 10, and the main convex lens 21 and the at least one sub convex lens 22 are used for collecting light emitted by the light source emitter 10 and refracting the light emitted by the light source emitter 10 to form parallel light which is at a certain angle with the horizontal direction to be emitted; the glass 30 is used for totally reflecting the light emitted from the main convex lens 21 and the at least one sub convex lens 22, so that a sensing area is formed in a region where the total reflection is performed on the glass 30; the receiving end lens 40 is used for focusing the light totally reflected by the glass; the photosensitive element 50 is used for receiving the light focused by the receiving lens 40.

The detection principle of the rainfall sensor is that when no rainwater exists on the surface of the glass, the glass 30 totally reflects the light rays which are emitted to the surface of the glass, and when the rainwater exists on the surface (sensing area) of the glass 30, the rainwater can damage the condition of the glass 30 for total reflection, and part of the light rays can be emitted outwards through the glass 30, so that the light rays reflected by the glass 30 are reduced, the light intensity is weakened, and the light sensing element 50 judges the rainfall according to the intensity of the received light signals.

According to the rainfall sensor, at least one sub-convex lens is additionally arranged in the convex lens at the transmitting end, namely, at least one refraction surface is additionally arranged, so that light emitted by the light source emitter is comprehensively collected, light emitted by the light source emitter penetrates through the newly-arranged refraction surface (sub-convex lens) to be refracted, and then is converged with light refracted by the main convex lens to be emitted to the glass, so that the area of a sensing area formed on the glass is larger, the area of the rainfall sensor detected by the glass is larger, and the rainfall sensitivity and reliability of the single rainfall sensor are effectively improved. Therefore, compared with the prior art, the rainfall sensor can effectively improve the detection area on glass on the premise of not arranging more photosensitive devices and sampling chips, further enhance the sensitivity and reliability of rain sensing, and has the advantages of lower cost, small volume and higher cost performance.

Further, considering that there may be a certain curvature of the glass 30, the transmitting-end lens 20 and the receiving-end lens 40, that is, the glass 30 cannot be tightly adhered to the transmitting-end lens 20 and the receiving-end lens 40, air may exist between the transmitting-end lens 20 and the glass 30 and between the receiving-end lens 40 and the glass 30, so that light cannot linearly propagate between the transmitting-end lens 20/the receiving-end lens 40 and the glass 30. Therefore, in the present embodiment, as shown in fig. 1, a transparent gel 60 is filled between the glass 30 and the transmitting lens 20, and a transparent gel 60 is also filled between the glass 30 and the receiving lens 40, and the refractive indexes of the transparent gel 60 and the glass 30, the transmitting lens 20 and the receiving lens 40 are similar. With this structural design, it is possible to ensure that no air exists between the transmitting-end lens 20 and the glass 30, and between the receiving-end lens 40 and the glass 30, so as to ensure that light can travel straight between the transmitting-end lens 20/the receiving-end lens 40 and the glass 30.

In particular, in the present embodiment, the refractive indexes of the transparent jelly 60 and the glass 30, the transmitting lens 20 and the receiving lens 40 are similar, which means that the refractive indexes of the four materials can satisfy that the light rays can propagate along a straight line between the transmitting lens 20/the receiving lens 40, the transparent jelly 60 and the glass 30. Of course, as a preferred embodiment, the transparent jelly 60 is the same as the refractive index of the glass 30, the transmitting lens 20 and the receiving lens 40.

In particular, in the present embodiment, the refractive index of the glass 30 is constant, so the critical angle at which total reflection occurs is constant, and therefore, in use, the angle of the light emitted from the light source emitter 10 needs to be controlled and adjusted by the emission end lens 20, so that the incident angle of the light on the glass 30 is larger than the critical angle when the light is emitted from the emission end lens 20 and then directed to the glass 30.

Preferably, in order to make the manufacture of the transmitting end lens 20 and the receiving end lens 40 easier, as shown in fig. 1, in this embodiment, the transmitting end lens 20 and the receiving end lens 40 are integrally designed, and in this embodiment, the material of the transmitting end lens 20 and the receiving end lens 40 is PC (polycarbonate), however, the present invention is not limited to the specific material, and in other alternative embodiments, any other material can be selected by those skilled in the art according to the specific situation, so long as the material can transmit light, and the refractive index of the material is similar to or the same as that of the glass 30. Further, in this embodiment, the transparent jelly 60 is silica gel, which plays a role of filling and connecting, and connects the transmitting lens 20, the receiving lens 40 and the glass 30 into a transparent whole. Of course, it should be noted that the present invention is not limited thereto, and in other alternative embodiments, one skilled in the art may select any material for the transparent jelly according to the need, so long as the refractive index of the transparent jelly is similar or the same as that of the glass 30.

Further, in the present embodiment, the light source emitter 10 employs an LED infrared light source, however, in other alternative embodiments, various LED light sources or other light source emitters may be selected to emit light other than infrared light. Specifically, in the present embodiment, the main convex lens 21 in the emitting end lens 20 is a collimating convex lens, the focal point of which coincides with the light emitting center point of the LED infrared light source, as shown in fig. 1 and 2, in the present embodiment, two sub-convex lenses 22 are provided, and the two sub-convex lenses 22 are each in a tooth shape, that is, the tooth-shaped sub-convex lenses 22 correspond to a single tooth structure in the fresnel lens, and the two sub-convex lenses 22 also coincide with the light emitting center point of the LED infrared light source, that is, in the present embodiment, the two sub-convex lenses 22 and the main convex lens 21 are collimating convex lenses with three different focal lengths, but the focal points of the three are coincident. Preferably, in the present embodiment, the interval between the two sub-convex lenses 22 is optimally 2mm, and in particular, in the present embodiment, the interval between the two sub-convex lenses 22 refers to the distance between the tooth tips of the two sub-convex lenses 22. For the receiving end lens 40, it is only used for receiving, and only the emitted light needs to be focused, so in this embodiment, the receiving end lens 40 is preferably a convex lens with a simpler structure, which can further reduce the cost.

Further, in order to further increase the sensing area of the rain sensor on the glass 30, so as to improve the rain sensitivity and the rain reliability of the rain sensor, and simultaneously save the cost and reduce the volume, preferably, as shown in fig. 3 and fig. 4, in this embodiment, the rain sensor includes two light source transmitters 10, namely, a first light source transmitter 101 and a second light source transmitter 102, respectively, two transmitting end lenses 20, namely, a first transmitting end lens 201 and a second transmitting end lens 202, respectively, two receiving end lenses 40, namely, a first receiving end lens 401 and a second receiving end lens 402, respectively, and a photosensitive element 50, wherein the first light source transmitter 101 is disposed corresponding to the first transmitting end lens 201, the second light source transmitter 102 is disposed corresponding to the second transmitting end lens 202, the first receiving end lens 401 is integrally connected with the second receiving end lens 402, and the focal point of the first receiving end lens 401 and the focal point of the second receiving end lens 402 coincide with the light receiving point of the element 50, respectively, and in this embodiment, the first receiving end lens 401 and the second receiving end lens 401 are defined as an angle α being equal to or less than or equal to 60 ° in the preferred embodiment.

By the structural design, namely a 'two-transmit and one-receive' structure, two sensing areas can be formed on the glass 30, specifically as shown in fig. 4, namely, a first light source emitter 101, a first emitting end lens 201, a first receiving end lens 401 and a photosensitive element 50 form a group of light paths to form a sensing area on the glass 30; the second light source emitter 102, the second emitting end lens 202, the second receiving end lens 402 and the photosensitive element 50 form a group of light paths to form another sensing area on the glass 30, light rays in the two groups of light paths are received by the photosensitive element 50, and two light path signals, namely light rays totally reflected by the two sensing areas on the glass 30, can be detected by one photosensitive element 50, so that the use of a photosensitive device is reduced, the cost is reduced, the volume is reduced, the area of the sensing area on the glass 30 is increased, and the rain sensitivity and reliability of the rain sensor are effectively improved.

The rain sensor has the beneficial effects that at least two toothed sub-convex lenses are arranged on the lens at the transmitting end, namely, two refracting surfaces are added to comprehensively collect light emitted by the light source transmitter, the light is converged with the light refracted by the main convex lens after penetrating through the newly added refracting surfaces, the collecting channel of the light is increased, so that the light area of the glass surface is increased, the area of a sensing area formed on the glass is increased on the premise that more photosensitive devices and sampling chips are not needed, the intensity of a light signal received by the photosensitive elements is effectively improved, the rain sensing sensitivity and reliability of the rain sensor are enhanced, meanwhile, the two-transmitting and two-receiving effect is realized through 'two-transmitting and one-receiving', the cost is lower, the volume is smaller, and the cost performance of a product is higher.

In summary, the rain sensor solves the problems of high manufacturing cost and large volume caused by the rain sensor in the prior art for improving the sensitivity and reliability of rain sensing. Therefore, the invention effectively overcomes various defects in the prior art and has high industrial utilization value.

The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (9)

1. A rainfall sensor, characterized by comprising:

a light source emitter for emitting light;

the emitting end lens is provided with a preset distance from the light source emitter, and comprises a main convex lens and at least one sub-convex lens arranged on one side of the main convex lens, wherein the focus of the main convex lens and the focus of the at least one sub-convex lens are overlapped with the light emitting center of the light source emitter, and the main convex lens and the at least one sub-convex lens are used for collecting light emitted by the light source emitter and refracting the light emitted by the light source emitter to form parallel light which is emitted in a certain angle with the horizontal direction;

a glass for totally reflecting light emitted from the main convex lens and the at least one sub-lens, thereby forming a sensing region in a region where the glass totally reflects;

a receiving end lens for focusing the light totally reflected by the glass;

and the photosensitive element is used for receiving the light focused by the receiving end lens.

2. A rainfall sensor according to claim 1, characterised in that: transparent jelly is filled between the glass and the transmitting end lens and between the glass and the receiving end lens, and the refractive indexes of the transparent jelly and the glass, the transmitting end lens and the receiving end lens are similar.

3. A rainfall sensor according to claim 1 or 2, characterised in that: the transmitting end lens and the receiving end lens are integrally designed.

4. A rainfall sensor according to claim 1, characterised in that: the number of the sub convex lenses is two, and the two sub convex lenses are tooth-shaped.

5. A rainfall sensor according to claim 4 wherein: the distance between the tooth tips of the two sub convex lenses is 2mm.

6. A rainfall sensor according to claim 1, characterised in that: the light source emitter comprises an LED infrared light source.

7. A rainfall sensor according to claim 1, characterised in that: the main convex lens is made of polycarbonate.

8. A rainfall sensor according to claim 1, wherein there are two light source transmitters, two light emitting end lenses, two light receiving end lenses and one light sensing element, wherein the two light source transmitters are in one-to-one correspondence with the two light emitting end lenses, the two light receiving end lenses are connected into a whole, and the focal points of the two light receiving end lenses coincide with the light receiving points of the light sensing element, and the included angle formed by the two light receiving end lenses is defined as alpha, and is 50-alpha-180 degrees.

9. A rainfall sensor according to claim 8 wherein: the alpha is 60 deg..

Images