Rain and fog sensor, laminated glass and automobile

Abstract

The present application relates to a kind of rain and fog sensor, laminated glass and car, the rain and fog sensor includes capacitance digital conversion circuit, switch array, FPC board;The front surface of the FPC board is arranged with at least three mutually insulated rain amount detection electrodes, back is arranged with at least two independent mutually insulated fog amount detection electrodes, the coverage area of the rain amount detection electrode is greater than the fog amount detection electrode, and each the fog amount detection electrode is covered by the rain amount detection electrode in the normal projection of FPC board;Each rain amount detection electrode is respectively electrically connected capacitance digital conversion circuit and ground by switch array time-sharing gating, each fog amount detection electrode is electrically connected capacitance digital conversion circuit.

Description

Technical Field

[0001] This invention relates to a rain and fog sensor, suitable for detecting rain and fog on laminated glass such as automotive windshields and sunroofs. Background Technology

[0002] Traditional rain and fog sensors used to detect the amount of rain and fog on a car's windshield are installed inside the windshield. They require components such as a sensor film, sensor, sensor bracket, and sensor base, which presents issues such as the cost of molds for the sensor housing, bracket, and base, as well as the problem of obstruction of the view.

[0003] To improve the aforementioned problems and resolve the mutual interference in rain and fog detection in the invention patent application No. 201780003059.8, as well as the interference of fogging on the back of the windshield during heavy rain on rainfall detection, CN201811301137.5 and CN201811301102.1 proposed the idea of ​​sandwiching the detection electrode between the inner and outer layers of the car's windshield and setting up a shielding electrode. However, because it requires setting up both rain and fog detection electrodes, and also setting up shielding electrodes on the back of the rain detection electrode and the front of the fog detection electrode, there is a drawback in the large space required for sensor electrode arrangement. In other words, the shielding electrode proposed to solve the interference inevitably leads to an increase in the space required for sensor electrode arrangement, which conflicts with the need to leave space for other sensors in the windshield area for integration and intelligent control. Summary of the Invention

[0004] The purpose of this invention is to improve upon the shortcomings of the prior art and to provide a rain and fog sensor and laminated glass and automobiles using the rain and fog sensor.

[0005] The aforementioned rain and fog sensor includes a capacitive digital conversion circuit, a switch array, and an FPC board. At least three mutually insulated rain detection electrodes are arranged on the front side of the FPC board, and at least two independent mutually insulated fog detection electrodes are arranged on the back side. The coverage area of ​​the rain detection electrodes is larger than that of the fog detection electrodes, and each fog detection electrode is covered by the normal projection of the rain detection electrode onto the FPC board. Each rain detection electrode is electrically connected to the capacitive digital conversion circuit and ground via the switch array in a time-division multiplexing manner, and each fog detection electrode is electrically connected to the capacitive digital conversion circuit. During the detection process, the capacitance values ​​of the fog and rain detection electrodes are set for time-sharing detection. When detecting the capacitance value of the fog detection electrode, the grounding and shielding of each rain detection electrode are controlled. Furthermore, when detecting the capacitance value of the rain detection electrode, the detection data of the fog detection electrode is used to correct the detection data of the rain detection electrode. This solves the interference of raindrops on fog detection and fog on raindrop detection. At the same time, the rain detection electrode is reused for both rain detection and fog detection shielding, achieving high space utilization and small size, leaving space for the installation of other sensors in the windshield area.

[0006] Furthermore, the rainfall detection electrodes are symmetrically arranged to form at least two pairs of symmetrical electrodes or groups of symmetrical electrodes, wherein the symmetrical area, shape, and spacing of each pair of symmetrical electrodes or groups of symmetrical electrodes are equal; the capacitance-to-digital conversion circuit can acquire the mutual capacitance of each pair of symmetrical electrodes or groups of symmetrical electrodes and / or the self-capacitance of each rainfall detection electrode through a switch array. Under the above hardware structure, periodic time-division measurement can be adopted in the program. Taking three electrodes as an example, one measurement cycle T can be divided into 6 measurement periods: T1, T2, ... T6, where the mutual capacitance is measured in periods T1, T2, and T3, and the self-capacitance is measured in periods T4, T5, and T6. The symmetrical raindrop sensor transmits the mutual capacitance of each pair of symmetrical electrodes or groups of symmetrical electrodes and / or the self-capacitance of each rain detection electrode to the main control circuit and other processing systems. Firstly, since rainfall data, except for extreme heavy rain, is discrete and asymmetrical, while temperature drift is uniform and symmetrical, the main control circuit can easily distinguish between slow accumulation of light rain and temperature drift data based on the symmetry of the data, reducing the false alarm rate caused by temperature drift and improving the sensitivity for light rain. Secondly, extreme heavy rain that can form a water film is relatively uniform self-capacitance symmetrical data (the mutual capacitance remains unchanged after the water film forms), while the data formed by a human hand touching the sensor is asymmetrical. Therefore, the main control circuit can distinguish between extreme heavy rain and hand-touched data based on the symmetry of the self-capacitance, thus solving the problems of false alarms due to hand touching and data cessation due to extreme heavy rain. Mutual capacitance and self-capacitance are measured using a time-division multiplexing method, which, under the current high-speed processing capabilities of chips, can meet the requirements of the rate of change in the natural environment in most cases. As a better improvement, differential capacitance can also be acquired. For example, a capacitance-to-digital converter circuit can acquire the differential capacitance formed by three rain detection electrodes or three rain detection electrode groups through a switch array. By utilizing the characteristic of simultaneous detection of differential capacitance that can already be achieved by CDC hardware resources, the sensing and identification in extreme cases can be solved.

[0007] Furthermore, the fog detection electrodes are paired to form an electrode unit. The two fog detection electrodes in an electrode unit are configured on the same plane, formed by parallel wires at a certain interval in a curved shape. There are at least two electrode units, each symmetrically arranged to form at least one pair of symmetrical electrode units or groups of symmetrical electrode units. The symmetrical area, shape, and spacing of each pair or group of symmetrical electrode units are equal. The capacitance-to-digital conversion circuit can acquire the mutual capacitance between the two fog detection electrodes in each electrode unit through a switch array. Similarly, the mutual capacitance can be obtained through periodic time-division measurement. The capacitive fog detection electrodes can then detect changes in fog formation. Since fogging on glass starts from the edge, the electrode units closer to the edge change first, followed by those farther away, exhibiting an asymmetric characteristic. Utilizing this characteristic, by acquiring the mutual capacitance of each electrode unit, the asymmetry of the data can easily filter out environmental interference in fog detection, thereby reducing false triggers and improving accuracy. As a further improvement, the capacitance-to-digital conversion circuit also acquires the differential capacitance formed by three electrode units or groups of three electrode units through a switch array.

[0008] Furthermore, the symmetrical points of each fog detection electrode and the symmetrical points of each rain detection electrode are located on the normal line of the same FPC board; the capacitor-to-digital converter circuit is set on this normal line. At this time, a significant advantage is that the electrode leads between each fog detection electrode, the rain detection electrode and the capacitor-to-digital converter circuit can be symmetrical, thereby achieving the symmetry of the electrode leads and further improving the accuracy of the sensor.

[0009] Furthermore, the rain and fog sensor may or may not include a main control circuit. If it is not included, the sensor transmits the acquired data externally, and the capacitor-to-digital converter circuit is electrically connected to the main control circuit. Preferably, at least two of the capacitor-to-digital converter circuit, the main control circuit, and the communication circuit are integrated into the R-SpiNNaker chip. The R-SpiNNaker chip also integrates a switch array, enabling at least two or all of the signal acquisition, processing, and output functions to be performed on a single chip, significantly reducing the number of components. For details regarding the R-SpiNNaker chip, please refer to patent document CN202110956246.6.

[0010] Furthermore, each rainfall detection electrode is configured as a rectangle, fan shape, or polygon; or the spacing between fog detection electrodes in each electrode unit is between 0.5 and 2 mm, and / or the electrode width of each fog detection electrode is between 0.5 and 2 mm.

[0011] The sensor of this invention can be applied to automotive windshields, as well as sunroofs, architectural glass, marine glass, aircraft glass, and other laminated glass. The laminated glass has an outer glass layer and an inner glass layer, and includes the aforementioned rain and fog sensor. Each rain detection electrode is arranged between the outer and inner glass layers. All electrodes are made of transparent material to avoid obstructing the view.

[0012] Another vehicle is provided, which includes the aforementioned laminated glass. Attached Figure Description

[0013] Figure 1 This is a schematic diagram showing the unfolded structure of the laminated glass containing the rain and fog sensor.

[0014] Figure 2 This is a module distribution diagram of the rain and fog sensor.

[0015] Figure 3 This is a schematic diagram of the cross-sectional structure of laminated glass.

[0016] Figure 4-1 This is a schematic diagram showing the relationship between the area of ​​the clustered integrated circuits and the overall glass area.

[0017] Figure 4-2 This is a schematic diagram showing the relationship between the area of ​​the clustered integrated circuits and the overall sensor board area.

[0018] Figure 5 This is a schematic diagram showing the layered structure of the electrode module.

[0019] Figure 6 This is a schematic diagram of symmetrically distributed electrodes for raindrop detection.

[0020] Figure 7 A schematic diagram of eight annular electrodes symmetrically distributed for fog detection.

[0021] Figure 8 This is a schematic diagram showing the spacing and width of the fog detection electrodes.

[0022] Figure 9 This is a schematic diagram of the fogging sensor glass arrangement and fogging process.

[0023] Figure 10 A schematic diagram illustrating how a fog shielding layer can block interference from fog and raindrop detection.

[0024] Figure 11 A schematic diagram illustrating how a rain shielding layer protects against the interference of raindrops on fog detection.

[0025] Figure 12 This is a schematic diagram of the differential capacitor principle. Detailed Implementation

[0026] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0027] like Figure 1 The diagram shown is an unfolded view of the laminated glass structure of the present invention, which includes a rain and fog sensor. It includes an outer glass plate 10, an inner glass plate 40, a PVB film 20 for bonding the inner and outer glass layers, and a sensor plate 30. The sensor plate is as follows... Figure 2 As shown, it is generally divided into three functional modules. The sensor electrode module 301 collects the signals required for the product's functions, including rain signals from the outer glass plate and fog signals from the inner glass plate. The sensor electrodes are formed by multiple copper-clad layers inside the FPC board. The integrated circuit module 500 collects analog information from the electrodes, performs analog-to-digital conversion, data processing and control, and communication protocol processing. Its structure consists of multiple components or integrated chips, thicker than the FPC, mounted together on the FPC board. The external connection port 400 allows the laminated glass to communicate with the outside world (such as a car's in-vehicle system) or can be used for power input. It generally needs to extend beyond the laminated glass to establish an electrical connection with the outside. Of course, wireless communication can also be used for digital communication. In a wired configuration, only one connector is needed for power supply and data communication; in this case, the components between the outer and inner glass plates are powered by the car's in-vehicle system. In a wireless configuration, the communication circuit can establish signal transmission with the in-vehicle system via radio frequency methods such as RF or Bluetooth. In another power supply scheme, power can also be supplied through a photovoltaic thin film sandwiched between an outer glass plate and an inner glass plate.

[0028] The aforementioned integrated circuit module 500 can be composed of a capacitor-to-digital converter circuit, a main control circuit, and a communication circuit. In terms of position, the components constituting each circuit are clustered together. This clustering should be understood as forming a circumscribed circle with the outer contour of the central component, with a radius of R. Concentric circles are constructed with a radius of R+5mm, and other components are arranged within the concentric circles. In terms of electrical connection, the electrode module is electrically connected to the capacitor-to-digital converter circuit. The main control circuit is connected to both the capacitor-to-digital converter circuit and the communication circuit. Each rain detection electrode can be selectively connected to the capacitor-to-digital converter circuit and ground via a switch array. Each fog detection electrode is electrically connected to the capacitor-to-digital converter circuit.

[0029] To ensure that the integrated circuit module can be properly bonded to the laminated glass, such as Figure 3The sum of the thickness of the thickest component 500 in the integrated circuit and the thickness of the FPC board (X2) should be less than the thickness of the PVB film 200 (X3). The two edge points of the thickest component 500 in the thickness direction serve as boundaries, and other components are constrained within these boundaries in the thickness direction. Simultaneously, within the integrated circuit module, the PVB film at corresponding positions needs to be reduced to avoid obstructing the components within the module. The reduction of PVB film can be achieved by creating blind vias for embedding, for example, reducing the thickness of a single, thicker layer of PVB and then locally filling the gaps with a patch (resin or PVB adhesive). Alternatively, the reduction can be performed on one of multiple thinner PVB sheets, with the gaps filled on another sheet. It should be understood that not filling the gaps to form a through-hole structure is also a feasible solution. In the above, a blind via can be understood as one surface of each component in the embedding direction being filled with resin or PVB adhesive. In another solution, all surfaces of each component in the embedding direction can be filled with resin or PVB adhesive.

[0030] To reduce the impact of PVB film reduction on the lamination quality of laminated glass, it is necessary to lower the ratio of the area of ​​the reduced film area to the total PVB film area. For example... Figure 4-1 The area ratio of S2 / S1 shown should generally be around 0.73. -5 Within this area. To reduce the area requiring adhesive removal, the layout of components in integrated circuit design needs to be as compact as possible, reducing the ratio of integrated circuit area to the overall PFC board area. For example... Figure 4-2 The area ratio of S2 / S3 is generally between 2.1% and 4.8. Depending on the specific requirements, integrated circuits can be placed in different locations within the laminated glass. For example, the adhesive reduction module corresponding to the integrated circuit may be entirely located inside the PVB film, with the adhesive reduction area being a closed region surrounded by the PVB film. Alternatively, the adhesive reduction area corresponding to the integrated circuit may be located at the edge of the PVB film, forming a semi-enclosed area.

[0031] like Figure 5 As shown, the sensor electrodes are formed by multiple copper-clad layers inside the FPC board. Electrode group 401, located near the outer glass layer 10, is used to detect raindrops and is positioned on the front side of the FPC board. A substrate insulating layer 402 isolates the upper and lower copper-clad layer electrodes. Electrode group 404, located near the inner glass layer 40, is used to detect fogging and is positioned on the back side of the FPC board. The coverage area of ​​electrode group 401 is larger than that of electrode group 404, and each electrode in electrode group 404 is covered by the normal projection of electrode group 401 onto the FPC board.

[0032] like Figure 6As shown, the four rain detection electrodes on the front are: electrode 100-1, electrode 100-2...electrode 100-4. Electrodes 100-1...100-4 form self-capacitances C1, C2...C4; electrodes 100-1 and 100-2 form mutual capacitance C5; electrodes 100-2 and 100-4 form mutual capacitance C6; electrodes 100-3 and 100-4 form mutual capacitance C7; and electrodes 100-3 and 100-1 form mutual capacitance C8. In other words, electrodes 100-1 and 100-2 form the first pair of symmetrical electrodes, electrodes 100-2 and 100-4 form the second pair of symmetrical electrodes, electrodes 100-4 and 100-3 form the third pair of symmetrical electrodes, and electrodes 100-1 and 100-3 form the fourth pair of symmetrical electrodes. One measurement cycle T can be divided into 8 measurement periods: T1, T2, ... T8. The capacitance changes in each channel C1, C2, ... C8 are detected in a time-division manner through the switch array in the integrated circuit.

[0033] When raindrops of different sizes begin to fall unevenly on the sensor surface, raindrops of varying sizes and quantities are distributed across each detection electrode surface and the gaps between electrodes. The presence or absence of raindrops can be determined by observing the uneven changes in self-capacitance C1, C2…C4 and mutual capacitance C5, C6…C8, thus assessing the amount of rainfall. However, when environmental factors such as temperature or humidity around the sensor change, these changes essentially cover the relatively small area of ​​the sensor. In this case, the changes in self-capacitance C1, C2…C4 and mutual capacitance C5, C6…C8 will exhibit relative consistency, thus eliminating the negative impact of capacitance changes caused by environmental factors.

[0034] It should be understood that electrodes 100-1, 100-2, ..., 100-4 do not need to be a single piece, but can be assembled in a modular fashion to form symmetrical electrode groups. For example, electrode 100-1 can be divided in half to form two electrodes, left and right. These two electrodes can be short-circuited together using a switch array to form a symmetrical electrode group. The remaining raindrop detection electrodes can be processed similarly. In this case, the time-division detection object using the switch array in the integrated circuit can be transformed into the mutual capacitance between each pair of symmetrical electrode groups and the self-capacitance of each electrode. It should also be understood that, based on the above principle, in applications, only a minimum of two pairs of symmetrical electrodes or symmetrical electrode groups are needed for symmetry determination, where the symmetrical area, shape, and spacing of each pair of symmetrical electrodes or symmetrical electrode groups are equal.

[0035] In other embodiments, based on the area and shape of the rain sensor layout region and the number of hardware capacitance channels, electrodes of different numbers and shapes can be arranged symmetrically, such as 3-fan, 4-square, 6-square, interlocking, polygonal, etc. The self-capacitance and mutual capacitance configurations should be paired according to the above symmetry rules. For differential electrodes, extra care is needed to ensure overall symmetry in the symmetrical electrode configuration. The case of 4-fan electrodes is illustrated below. Figure 6 By using an array switch, electrodes 100-1 and 100-3 are shorted together to form a single electrode, serving as the common excitation terminal of the differential capacitor. Electrodes 100-2 and 100-4 serve as the two receiving terminals of the differential capacitor, respectively. This ensures the overall symmetry of the differential capacitor along its vertical centerline. To construct a symmetrical electrode group with four sector-shaped electrodes, the array switch can be used to short-circuit electrodes 100-1 and 100-3 to form one symmetrical electrode group, and short-circuit electrodes 100-2 and 100-4 to form another symmetrical electrode group. These two symmetrical electrode groups form a pair. Subsequently, electrodes 100-1 and 100-2 are short-circuited to form another symmetrical electrode group, and electrodes 100-3 and 100-4 are short-circuited to form yet another symmetrical electrode group, again forming a pair.

[0036] like Figure 7 As shown, the eight fog detection electrodes on the back are: electrode 300-1, electrode 300-2, electrode 300-3, electrode 300-4, electrode 300-5, electrode 300-6, electrode 300-7, and electrode 300-8. Figure 8 As shown, the spacing d2 between each electrode is between 0.5 and 2 mm, and the electrode width d1 of each fog detection electrode is between 0.5 and 2 mm. Electrode pairs 300-1 and 300-2 (also called electrode units)... electrode pairs 300-7 and 300-8 form mutual capacitances C1, C2...C4, respectively. Each electrode pair is formed in a curved shape by parallel wires at a certain spacing on the same plane. One measurement cycle T can be divided into four measurement periods: T1, T2,...T4. The capacitance changes in each channel of C1, C2,...C4 are detected time-divisionally using a switch array in the integrated circuit.

[0037] like Figure 9As shown, the fog sensor is positioned in the upper-middle part of the glass. The capacitance change caused by tiny water droplets adhering to the inner surface of the glass reflects the degree of fogging. Fogging begins at the edge of the glass and gradually spreads from the periphery towards the center. At this time, the mutual capacitances C1, C2, ... C4 formed by the symmetrical electrodes exhibit an asymmetrical characteristic for the gradually spreading fog: the electrode closer to the edge changes first, followed by the electrode farther away, thus determining fogging. When environmental factors such as temperature or humidity around the sensor change, these changes essentially cover the relatively small area of ​​the sensor. The changes in mutual capacitances C1, C2, ... C4 then show relative consistency, eliminating interference from capacitance changes caused by environmental factors.

[0038] exist Figure 7 In this model, electrode pairs 300-1 and 300-2, along with electrode pairs 300-3 and 300-4, form one pair of symmetrical electrode units. Electrode pairs 300-1 and 300-2, along with electrode pairs 300-5 and 300-6, form another pair of symmetrical electrode units. Similarly, each pair of symmetrical electrode units has the same area, shape, and spacing. Based on this principle, in applications, only one pair of symmetrical electrode units is needed for judgment. It should be understood that by shorting 300-1 and 300-3, and 300-2 and 300-4 using a switch array, a symmetrical electrode unit group can be formed. Then, by shorting 300-5 and 300-7, and 300-6 and 300-8, another symmetrical electrode unit group can be formed. Judgment can also be achieved using symmetry in the same way.

[0039] In other embodiments, given the limited number of hardware capacitor channels, two pairs of fog detection electrodes, or other symmetrically distributed electrodes, can be arranged. The configuration of self-capacitance and mutual capacitance follows the aforementioned symmetry rules. For differential electrodes, the configuration of symmetrical electrodes follows the aforementioned symmetry rules to ensure the overall symmetrical distribution of the differential capacitor electrodes. For fog detection sensors with two pairs of electrodes, special attention needs to be paid to the symmetrical design of the electrodes during use. For example, if the fog sensor is placed in the upper part of the glass, and the two pairs of electrodes are symmetrically designed vertically, fogging will first spread from the upper pair of electrodes to the lower pair, conforming to the characteristics of asymmetrical capacitance change; this scheme is feasible. However, if the fog sensor is placed in the upper part of the glass, and the two pairs of electrodes are symmetrically designed horizontally, fogging will spread from top to bottom, simultaneously covering both pairs of electrodes. The asymmetrical capacitance change characteristics during fogging cannot be well represented, therefore this design is not feasible and requires special attention.

[0040] During the detection process, the capacitance values ​​of the fog and rain detection electrodes are set for time-sharing detection. When detecting the capacitance value of the fog detection electrode, the grounding and shielding of each rain detection electrode are controlled. Furthermore, when detecting the capacitance value of the rain detection electrode, the detection data of the fog detection electrode is used to correct the detection data of the rain detection electrode. This solves the interference of raindrops on fog detection and fog on raindrop detection. At the same time, the rain detection electrode is reused to perform both rain detection and fog detection shielding, achieving the requirements of high space utilization and small size.

[0041] In an improved design, electrode 403 can also be used as a shielding electrode to block interference from fogging on the inner glass layer on raindrop detection. For example... Figure 10 As shown, when the raindrop detection electrode is working, the switch array in the integrated circuit short-circuits the other layer of mesh shielding electrode and the fogging electrode to form a single electrode, which is then grounded. This single electrode essentially covers the raindrop detection electrode, forming a shielding layer to block the interference of fogging on raindrop detection. Figure 11 As shown, when the fog detection electrode is working, the switch array in the integrated circuit connects the four fan-shaped rain electrodes on the other layer to form a whole electrode and then grounds it. The whole electrode can basically cover the fog detection electrode and shield the interference of raindrops.

[0042] Preferably, the circuit module integrated into the R-SpiNNaker chip acquires the differential capacitance formed by three symmetrically centered rain gauge electrodes or three symmetrical rain gauge electrode groups through a switch array, achieving the characteristic of simultaneous detection of differential capacitance. For example... Figure 12 As shown, there are three electrodes with equal area, shape, and spacing, symmetrically arranged around electrode 2. Electrode 2 serves as the common excitation terminal, while electrodes 1 and 2 are the two receiving terminals. Excitation electrode 2 and receiving electrode 1 form a mutual capacitance C1, and excitation electrode 2 and receiving electrode 3 form a mutual capacitance C2. The hardware of the R-SpiNNaker chip supports the direct detection of the capacitance difference C12 between C1 and C2 in a single measurement. This allows for accurate measurement of the capacitance difference between the symmetrical electrodes at a specific moment, accurately reflecting the uneven distribution of raindrops or fog on the electrodes at the same time. Previously, the time-division detection of self-capacitance or mutual capacitance mentioned above could not fully reflect the fog distribution on the surface of the symmetrical electrodes at the same time. Therefore, a hardware differential capacitance detection scheme is used to address sensor identification in extreme cases. Of course, with the current high-speed processing capabilities of chips, the time-division detection scheme can meet the requirements of the rate of change in the natural environment in most cases, and thus can also be applied to practical engineering applications.

[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A rain and fog sensor, characterized in that: The rain and fog sensor includes a capacitor-to-digital converter circuit, a switch array, and an FPC board; The FPC board has at least three mutually insulated rain detection electrodes arranged on its front side and at least two independent mutually insulated fog detection electrodes arranged on its back side. The coverage area of ​​the rainfall detection electrode is larger than that of the fog detection electrode, and each of the fog detection electrodes is covered by the normal projection of the rainfall detection electrode onto the FPC plate. Each of the rainfall detection electrodes is electrically connected to the capacitor-to-digital converter circuit and ground via a switch array, and each of the fog detection electrodes is electrically connected to the capacitor-to-digital converter circuit.

2. The rain and fog sensor according to claim 1, characterized in that: Each of the rainfall detection electrodes is symmetrically arranged to form at least two pairs of symmetrical electrodes or symmetrical electrode groups, wherein the symmetrical area, shape and spacing of each pair of symmetrical electrodes or symmetrical electrode groups are equal. The capacitance-to-digital conversion circuit can acquire the mutual capacitance of each pair of symmetrical electrodes or symmetrical electrode groups and / or the self-capacitance of each rain detection electrode through a switch array.

3. The rain and fog sensor according to claim 2, characterized in that: The fog detection electrodes are paired to form an electrode unit, and the two fog detection electrodes in the electrode unit are configured on the same plane and formed in a curved shape by parallel wires at a certain interval. The electrode unit has at least two, and each electrode unit is symmetrically arranged to form at least one pair of symmetrical electrode units or symmetrical electrode unit groups. The symmetrical area, shape and spacing of each pair of symmetrical electrode units or symmetrical electrode unit groups are equal. The capacitance-to-digital conversion circuit can obtain the mutual capacitance between the two fog detection electrodes in each electrode unit through a switch array.

4. The rain and fog sensor according to claim 3, characterized in that: The capacitance-to-digital conversion circuit also acquires the differential capacitance formed by three rain gauge electrodes or three groups of rain gauge electrodes through a switch array; and / or The number of electrode units is greater than or equal to three, and the capacitor-to-digital conversion circuit also obtains the differential capacitance formed by the three electrode units or the group of three electrode units through a switch array.

5. The rain and fog sensor according to claim 3, characterized in that: The symmetrical points of each fog detection electrode and the symmetrical points of each rain detection electrode are located on the normal line of the same FPC plate. The capacitor-to-digital converter circuit is located on the normal line, and the electrode leads between each fog detection electrode, rain detection electrode and the capacitor-to-digital converter circuit are symmetrically arranged.

6. The rain and fog sensor according to claim 1, characterized in that: The rain and fog sensor also includes a main control circuit, and the capacitor-to-digital converter circuit is electrically connected to the main control circuit.

7. The rain and fog sensor according to claim 6, characterized in that: At least two of the following configurations are integrated into the R-SpiNNaker chip: the capacitor-to-digital converter circuit, the main control circuit, and the switch array.

8. The rain and fog sensor according to claim 1, characterized in that: The capacitance values ​​of the fog detection electrode and the rain detection electrode are detected in a time-division manner. When detecting the capacitance value of the fog detection electrode, the detection data of the rain detection electrode is corrected by using the detection data of the fog detection electrode.

9. A laminated glass comprising an outer glass layer and an inner glass layer, characterized in that, The laminated glass includes a rain and fog sensor as described in any one of claims 1-8, with each of the rain detection electrodes arranged between the outer glass and the inner glass.

10. A car, characterized in that, The vehicle includes the laminated glass as described in claim 9.

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