Microstructure rainfall lens capable of increasing sensing area and rainfall sensor

Abstract

The invention relates to a microstructure rainfall lens capable of increasing induction area, which is characterized in that the microstructure rainfall lens comprises two lens groups, the lens groups are mounted on the inner side of glass, each lens group comprises a transmitting end lens and a receiving end lens, the receiving end lenses in the two lens groups are integrally connected and form a receiving area, and the receiving end lenses in the two lens groups are arranged in the receiving area. The receiving end lenses are composed of a plurality of receiving microstructure units so as to reduce shielding generated between the two receiving end lenses in the receiving area, and the receiving microstructure units, located in the receiving area, of the receiving end lenses in the two lens sets are mutually staggered to form a staggered area so as to reduce an invalid induction area. Compared with the prior art, the lens has the following advantages and effects that the whole lens is thinned, and the overlapped part of the receiving end lenses in the two groups of lenses is regionalized or gridded, so that the receiving end lenses of the two groups of lenses exist in each region or grid at the same time, the coverage range of an induction light path is effectively enlarged, and the whole induction area is effectively enlarged.

Description

Technical Field

[0001] The present invention relates to the technical field of rain sensors, and in particular to a microstructured rain lens with an increased sensing area. The present invention also relates to a rain sensor. Background Art

[0002] In automotive technology, rain sensors are the sensing elements that control the automatic start and stop of windshield wipers. They utilize the fundamental principle of total reflection when infrared light is incident from a denser material onto a less dense material at an angle greater than the critical angle. When water droplets fall into the rain sensor's detection area, the difference in refractive index between water and air causes some of the infrared light to be refracted, reducing the amount of reflected infrared light. Photoelectric sensing and software algorithms then calculate the amount and frequency of infrared light changes, thereby determining the amount of rainfall. The wiper's wiping speed and frequency are then controlled based on the amount of rainfall.

[0003] like Figure 1 As shown, at present, in order to improve the sensitivity of the rain sensor while controlling the overall processing cost, a two-transmitter-one-receiver structural design is adopted, that is, a two-group lens structure is adopted, and the receiving end lenses in each group of lenses are connected as a whole, which can form two sensing areas on the glass.

[0004] For example, the Chinese patent technology document with the announcement number CN116106991A discloses a rain sensor, including a light source emitter for emitting light; a transmitting end lens, which has a preset distance from the light source emitter, and the transmitting end lens includes a main convex lens and at least one sub-convex lens arranged on one side of the main convex lens, the focus of the main convex lens and the focus of the at least one sub-convex lens both coincide with the light-emitting center of the light source emitter, the main convex lens and the at least one sub-convex lens are used to collect the light emitted by the light source emitter and refract the light emitted by the light source emitter to form parallel light at a certain angle to the horizontal direction; glass, used to totally reflect the light emitted from the transmitting end lens, and the area where the glass is totally reflected is formed as a sensing area; the receiving end lens, used to focus the light totally reflected by the glass; the photosensitive element, used to receive the light focused by the receiving end lens.

[0005] In the above technical solution, after forming a two-transmitter-one-receiver structure, the light in the two groups of optical paths can be received by the photosensitive element. Two optical path signals can be detected by one photosensitive element, that is, the light totally reflected from the two sensing areas on the glass can be detected. While reducing the use of photosensitive devices to reduce costs and reduce volume, the area of the sensing area on the glass is also increased, effectively improving the rain sensitivity of the rain sensor.

[0006] However, in actual use, it was found that since the receiving end lens is a whole three-dimensional structure with curvature and thickness, after the receiving end lenses in the two groups are connected into a whole, there will be occlusion between the receiving end lenses (the high position area occludes the low position area, and the thick part occludes the thin part), thereby generating an invalid sensing area in the receiving area, resulting in a reduction in the overall effective sensing area, which in turn affects the overall sensing area of the rain sensor. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a microstructured rain lens with a larger sensing area. By thinning the entire lens and regionalizing or gridding the overlapping portions of the receiving lenses in the two lens groups, each region or grid contains receiving lenses from both lens groups. This effectively increases the coverage of the sensing optical path and, therefore, the overall sensing area. The present invention also provides a rain sensor.

[0008] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a microstructure rain gauge lens with increased sensing area, comprising two lens groups, wherein the lens groups are mounted on the inner side of the glass, the lens groups include a transmitting end lens and a receiving end lens, the receiving end lenses in the two lens groups are integrally connected to form a receiving area, the receiving end lens is composed of a plurality of receiving microstructure units to reduce the obstruction generated between the two receiving end lenses in the receiving area, and the receiving microstructure units of the receiving end lenses in the two lens groups are located in the receiving area and are staggered to form an interlaced area to reduce the invalid sensing area.

[0009] The present invention is further configured as follows: the emitting end lens is composed of a plurality of emitting microstructure units, a first inclination angle exists between the surface of the emitting microstructure unit and the plane, and the first inclination angle of the emitting microstructure unit increases sequentially from the center to the edge of the rainfall lens.

[0010] The present invention is further configured such that: a second inclination angle exists between the surface of the receiving microstructure unit and the plane, and the second inclination angle is adapted to the first inclination angle.

[0011] The present invention is further configured such that: the emitting microstructure and the receiving microstructure are both in the shape of tooth tips, and the spacing between adjacent emitting microstructure tooth tips and the spacing between adjacent receiving microstructure tooth tips are both 0.1 mm to 2 mm.

[0012] The present invention is further configured such that the overall thickness of the lens assembly is 1.5 mm to 2.5 mm.

[0013] The present invention is further configured as follows: a transparent carrier is provided between the lens group and the glass, and the refractive index of the transparent carrier is adapted to that of the lens group and the glass.

[0014] The present invention is further configured such that: the interlaced areas are in strip shape.

[0015] The present invention also provides a rain sensor, comprising the above-mentioned rain gauge lens, and also comprising a light source emitting element and a photosensitive element, wherein the light source emitting element and the photosensitive element are respectively at preset distances from the transmitting end lens and the receiving end lens, and the focus of the transmitting end lens coincides with the light emitting center of the light source emitting element. The transmitting end lens is used to collect the light emitted by the light source emitting element and refract it to form parallel light at a certain angle to the horizontal direction and project it toward the glass. The receiving end lens is used to focus the light totally reflected by the glass, and the photosensitive element is used to receive the light focused by the receiving end lens.

[0016] The present invention is further configured such that the light source emitting element is an LED infrared light source.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. Since the receiving end lens is composed of a plurality of receiving microstructure units, compared with the prior art in which the receiving end lens is a monolithic structure, when the receiving end lenses in the two lens groups are integrally connected to form a lens structure in a two-transmitting and one-receiving structure, since the receiving end lens is composed of a plurality of receiving microstructure units, the occlusion generated between the two receiving end lenses in the receiving area can be reduced. Because if the receiving end lens is a monolithic structure, when occlusion occurs between the two receiving end lenses, the occlusion area is the monolithic area, thereby reducing the overlapping portion of the two receiving end lenses in the receiving area, thereby reducing the invalid sensing area.

[0019] 2. Since the receiving end lenses in the two lens groups are located in the receiving area, the receiving microstructure units of each other are staggered to form an interlaced area. In this way, the receiving end lenses in the two lens groups can complement each other after being connected as one, so as to increase the range of parallel light that can be focused by total reflection, thereby reducing the invalid sensing area.

[0020] 3. By forming the emitting end lens with a plurality of emitting microstructure units, there is a first inclination angle between the surface of the emitting microstructure unit and the plane, and the first inclination angle of the emitting microstructure unit increases successively from the center to the edge of the rain lens. In this way, when light is emitted to the emitting end lens, since the emitted light is divergent light, by setting the emitting microstructure unit to a first inclination angle of different angles, it is possible to adapt to the different divergence angles of the emitted light, so that light with different divergence angles can be collimated into parallel light through refraction, thereby increasing the range of total reflection of the collimated parallel light on the glass, thereby increasing the overall sensing area of the rain lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the specific structure of a two-transmitter-one-receiver rain gauge sensor in the prior art;

[0022] Figure 2 Schematic diagram of the relationship between the rain gauge lens, the light source emitting element, and the light sensing element in the first embodiment of the present invention;

[0023] Figure 3 Schematic diagram of the optical path between the rain gauge lens, the light emitting element, and the light sensing element in Example 1 of the present invention;

[0024] Figure 4 Schematic diagram (1) of the relationship between the two lens groups in Example 1 of the present invention;

[0025] Figure 5 Schematic diagram (2) of the relationship between the two lens groups in Example 1 of the present invention;

[0026] Figure 6 Schematic diagram of the specific structure of the lens assembly in Example 1 of the present invention;

[0027] Figure 7 Schematic diagram of the relationship between the two lens groups in the second embodiment of the present invention. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate and simplify the description of the present invention. They are not intended to indicate or imply that the devices or components referred to must have, be constructed, or operate in a specific orientation, and therefore should not be construed as limitations on the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] Example 1

[0031] like Figures 2 to 4As shown, the present invention discloses a microstructure rain gauge lens with increased sensing area, comprising two lens groups, which are mounted on the inner side of a glass 1, and the lens groups comprise a transmitting end lens 2 and a receiving end lens 3. The receiving end lenses 3 in the two lens groups are integrally connected to form a receiving area. When the receiving end lenses 3 in the two lens groups are integrally connected to form a lens structure in a two-transmitting and one-receiving structure, since the receiving end lens 3 is composed of a plurality of receiving microstructure units 31, the occlusion generated between the two receiving end lenses 3 in the receiving area can be reduced. Because if the receiving end lens 3 is a whole-piece structure, when occlusion occurs between the two receiving end lenses 3, the occlusion area is a whole-piece area, thereby reducing the overlapping portion of the two receiving end lenses 3 in the receiving area, thereby reducing the invalid sensing area. In addition, the receiving microstructure unit 31 of the receiving end lens 3 can be further miniaturized, thereby further eliminating the invalid sensing area in the receiving area.

[0032] In addition, the receiving end lenses 3 in the two lens groups are located in the receiving area, and the receiving microstructure units 31 of each other are staggered to form an staggered area 100. In this way, the receiving end lenses 3 in the two lens groups can complement each other after being connected as one, so as to increase the range of parallel light that can be focused by total reflection, so as to further reduce the invalid sensing area.

[0033] Further as Figure 5 As shown, to facilitate identification of the interlaced relationship between the receiving microstructure units 31 of the two lens groups when they are located in the receiving area, the overlapping portions of the receiving lenses in the two lens groups are regionalized or gridded, so that each region or grid contains two sets of receiving lenses. Each lens group is marked with a blank portion and a shaded portion, respectively. The receiving lens 3 in the blank portion and the transmitting lens 2 in the blank portion form a lens group, and the receiving lens 3 in the shaded portion and the transmitting lens 2 in the shaded portion form a lens group. As can be seen from the figure, the sensing area of the lens group in the blank portion is not reduced due to lens overlap or cutting, and its area is substantially equal to the complete area of the transmitting lens 2. In contrast, in the prior art, the receiving lens 3 connected as one body in the two-transmitter-one-receiver structure has a large amount of overlapping portions, and its sensing area is significantly smaller than the area of the transmitting lens 2. In extreme cases, it is only half the area of the transmitting lens 2. This shows that the receiving lens 3 structure of the present invention can increase the coverage of the sensing light path, thereby effectively increasing the overall sensing area.

[0034] like Figure 6As shown, in this embodiment, the emitting end lens 2 is composed of a plurality of emitting microstructure units 21, and there is a first inclination angle between the surface of the emitting microstructure unit 21 and the plane. The first inclination angle of the emitting microstructure unit 21 increases successively from the center to the edge of the rain lens. In this way, when light is emitted to the emitting end lens 2, since the emitted light is divergent light, by setting the emitting microstructure unit 21 to a first inclination angle of different angles, it is possible to adapt to different divergence angles of the emitted light, so that light with different divergence angles can be collimated into parallel light through refraction, thereby increasing the range of total reflection of the collimated parallel light on the glass 1, thereby increasing the overall sensing area of the rain lens.

[0035] In this embodiment, there is a second inclination angle between the surface of the receiving microstructure unit 31 and the plane, and the second inclination angle is adapted to the first inclination angle. It should be noted that the adaptation of the second inclination angle to the first inclination angle means that the setting of the second inclination angle means that the light emitted to a certain emitting microstructure unit 21 is refracted and collimated by the emitting microstructure unit 21 and then emitted to the glass 1, and is totally reflected by the glass 1 to the corresponding receiving microstructure unit 31, and can be focused by the corresponding receiving microstructure unit 31.

[0036] In addition, it should be noted that in the field of rain sensor technology, the principle of total internal reflection in glass 1 is that when light is incident from a denser medium to a less dense medium, if the critical angle condition is met, the light no longer exits the interface but is instead totally reflected within the denser medium. Therefore, when the denser medium is glass 1, its refractive index is typically 1.52, while when the less dense medium is air, its refractive index is 1. The formula for calculating the critical angle shows that the critical angle for glass 1 incident on air is 41.1395 degrees. Therefore, total internal reflection occurs when the incident angle is greater than this angle.

[0037] In this embodiment, the transmitting microstructure and the receiving microstructure are both in the shape of tooth tips. By setting the spacing between adjacent transmitting microstructure tooth tips and the spacing between adjacent receiving microstructure tooth tips to 0.1mm-2mm, the sensing light spot formed on the glass 1 can be made more uniform, thereby improving the accuracy and sensitivity of rain sensing. The overall thickness of the lens group is 1.5mm-2.5mm, which has an ultra-thin characteristic, so as to reduce the mutual occlusion between the two groups of receiving end lenses.

[0038] It should be noted that in order to facilitate the overall processing, when forming the structure of two transmitting and one receiving lenses, the receiving end lens 3 in the two lens groups is set as an integral whole, and the lens group is made of PC material (polycarbonate), so it can be processed by injection molding, which effectively improves the processing efficiency.

[0039] In addition, since there may be a certain curvature between the glass 1 and the lens group, which makes it impossible for the two to fit tightly, a transparent carrier 4 is further provided between the lens group and the glass 1. The material of the transparent carrier 4 can be the same as that of the lens group, and for the convenience of processing, the transparent carrier 4 can also be processed together with the lens group by injection molding. In addition, the refractive index of the transparent carrier 4, the lens group and the glass 1 needs to be adapted, that is, as long as the refractive index between the three can satisfy the light propagation in a straight line between the lens group, the transparent carrier 4 and the glass 1.

[0040] Example 2

[0041] like Figure 7 As shown, the difference of this embodiment is that the interlaced area 100 is strip-shaped, which is another form of expression of the microstructure in the interlaced area 100. In order to facilitate the identification of the interlaced relationship between the receiving microstructure units 31 of the two lens groups when the receiving end lenses 3 are located in the receiving area, each lens group is also marked with a blank part and a shaded part respectively. The receiving end lens 3 in the blank part and the transmitting end lens 2 in the blank part are a lens group, and the receiving end lens 3 in the shaded part and the transmitting end lens 2 in the shaded part are a lens group.

[0042] like Figures 2 to 3 As shown, the present invention also discloses a rain sensor, including the above-mentioned rain lens. The use of the above-mentioned rain lens can effectively improve the sensitivity and accuracy of the rain sensor. The rain sensor also includes a light emitting element 5 and a photosensitive element 6. The light emitting element 5 and the photosensitive element 6 are respectively at preset distances from the transmitting end lens 2 and the receiving end lens 3. The focus of the transmitting end lens 2 coincides with the light emitting center of the light emitting element 5. The transmitting end lens 2 is used to collect the light emitted by the light emitting element 5 and refract it to form parallel light at a certain angle to the horizontal direction and project it toward the glass 1. The receiving end lens 3 is used to focus the light totally reflected by the glass 1, and the photosensitive element 6 is used to receive the light focused by the receiving end lens 3.

[0043] The detection principle of this rain sensor is that when there is no rain on the surface of the glass 1, the glass 1 will totally reflect the light incident on its surface. When there is rain on the surface of the glass 1 (sensing area), the rain will destroy the conditions for total reflection of the glass 1, and part of the light will be emitted outward through the glass 1, thereby reducing the light reflected by the glass 1 and weakening the light intensity. The photosensitive element 6 judges the amount of rainfall based on the strength of the light signal it receives, and the light emitting element 5 can use an LED infrared light source.

[0044] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A microstructured rain lens with increased sensing area, characterized in that: The invention comprises two lens groups, which are installed on the inner side of the glass. The lens groups include a transmitting end lens and a receiving end lens. The receiving end lenses in the two lens groups are integrally connected to form a receiving area. The receiving end lens is composed of a plurality of receiving microstructure units to reduce the obstruction generated between the two receiving end lenses in the receiving area. The receiving microstructure units of the receiving end lenses in the two lens groups are located in the receiving area and are staggered to form an interlaced area to reduce the invalid sensing area.

2. The microstructured rain lens with increased sensing area according to claim 1, characterized in that: The emitting end lens is composed of a plurality of emitting microstructure units. A first inclination angle exists between the surface of the emitting microstructure unit and the plane. The first inclination angle of the emitting microstructure unit increases sequentially from the center to the edge of the rainfall lens.

3. The microstructured rain lens with increased sensing area according to claim 2, characterized in that: There is a second inclination angle between the surface of the receiving microstructure unit and the plane, and the second inclination angle is adapted to the first inclination angle.

4. The microstructured rain lens with increased sensing area according to claim 3, characterized in that: The emitting microstructure and the receiving microstructure are both in the shape of tooth tips, and the spacing between adjacent emitting microstructure tooth tips and the spacing between adjacent receiving microstructure tooth tips are both 0.1 mm to 2 mm.

5. A microstructured rain lens with increased sensing area according to claim 1 or 3, characterized in that: The overall thickness of the lens assembly is 1.5 mm to 2.5 mm.

6. The microstructured rain lens with increased sensing area according to claim 1, characterized in that: A transparent carrier is provided between the lens group and the glass, and the refractive index of the transparent carrier, the lens group and the glass are adapted.

7. The microstructured rain lens with increased sensing area according to claim 1, characterized in that: The interlaced areas are in strip shape.

8. A rain sensor, characterized in that: A rain gauge lens according to any of the above claims, further comprising a light source emitting element and a photosensitive element, wherein the light source emitting element and the photosensitive element are respectively at preset distances from the transmitting end lens and the receiving end lens, the focus of the transmitting end lens coincides with the light emitting center of the light source emitting element, the transmitting end lens is used to collect the light emitted by the light source emitting element, and refract it to form parallel light at a certain angle to the horizontal direction and project it toward the glass, the receiving end lens is used to focus the light totally reflected by the glass, and the photosensitive element is used to receive the focused light of the receiving end lens.

9. A rain sensor according to claim 8, characterized in that: The light source emitting element is an LED infrared light source.

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