A heating trigger module for automotive rearview mirrors

Abstract

This utility model relates to the field of sensing heating control technology, and discloses a car rearview mirror heating trigger module with high reliability and good stability. It includes a capacitive sensor (200) for acquiring the electrical threshold formed on the glass mirror when it is wet or dry, and a main control module (130). The main control module (130) is used to acquire the electrical threshold formed by the capacitive sensor (200). When the main control module (130) detects that the electrical threshold increases, it outputs a PWM signal to control the heater to heat the glass mirror. The main control module (130) is used to detect the temperature value of the glass mirror. When the temperature value reaches the preset value, the main control module (130) adjusts the duty cycle of the PWM signal to control the temperature value of the glass mirror.

Description

Technical Field

[0001] This utility model relates to the field of sensing heating control technology, and more specifically, to a heating trigger module for a car rearview mirror. Background Technology

[0002] When a vehicle is in heavy rain, rearview mirrors easily become wet and unusable. Traditional solutions mainly fall into two categories:

[0003] With manual control of heated rearview mirrors, drivers need to judge the weather conditions and manually turn on the heated mirror function, but it is easy to forget to turn it on, resulting in poor visibility in rainy weather, or accidentally turning it on (such as turning it on in sunny weather), wasting energy and affecting the life of the heating element.

[0004] Automatic control based on sensors inside the vehicle / rearview mirror housing: High-end models typically use a windshield rain sensor or an in-vehicle temperature and humidity sensor to indirectly determine whether the rearview mirror heating needs to be turned on.

[0005] However, there is a triggering delay problem: because the sensor is located inside the vehicle or in the rearview mirror housing, airflow is difficult to enter, resulting in a detection delay (such as triggering only after rain has severely affected the field of vision).

[0006] High false positive rate:

[0007] High humidity inside the car (such as from passengers breathing or the air conditioner defogging) may be mistaken for a rainy day.

[0008] When driving at low speeds, insufficient airflow makes it difficult for sensors to accurately detect external rain conditions.

[0009] In environments with large temperature differences (such as cold winter weather), the mirror surface may fog up instead of directly adhering to rainwater, but traditional systems cannot accurately distinguish between them.

[0010] Systems that rely solely on rain sensors may not respond correctly to mud splashes or light mist.

[0011] Systems that rely solely on temperature and humidity sensors may misjudge conditions due to airflow at high speeds. Summary of the Invention

[0012] The technical problem to be solved by this utility model is to address the shortcomings of the existing technology, which is that humidity sensors are often installed inside the vehicle, and even if they are installed inside the rearview mirror housing, the airflow does not easily enter the vehicle or the rearview mirror housing during vehicle operation, resulting in limited triggering effect. This utility model provides a car rearview mirror heating trigger module with higher reliability and better stability.

[0013] The technical solution adopted by this utility model to solve its technical problem is: constructing a car rearview mirror heating trigger module, which has the following features:

[0014] A capacitive sensor, which is attached to the rearview mirror glass, is used to obtain the electrical threshold formed on the glass mirror when it is wet or dry.

[0015] The main control module has its signal terminal connected to the signal terminal of the capacitance sensor, and is used to obtain the electrical threshold formed by the capacitance sensor.

[0016] When the main control module detects an increase in the electrical threshold, it outputs a PWM signal to control the heater to heat the glass mirror.

[0017] The main control module is used to detect the temperature value of the glass mirror. When the temperature value reaches a preset value, the main control module adjusts the duty cycle of the PWM signal to control the temperature value of the glass mirror.

[0018] In some embodiments, the capacitive sensor includes at least an upper electrode, an insulating layer, and a lower electrode stacked together.

[0019] The upper electrode is positioned at the top to acquire the electrical threshold formed on the glass mirror when it is wet or dry.

[0020] The insulating layer is disposed on the lower end face of the upper electrode and serves as a dielectric or insulating layer.

[0021] The lower electrode is disposed on the lower end face of the isolation layer and cooperates with the upper electrode to form a signal sensing.

[0022] In some embodiments, a power conversion module is also included, the input of which is used to receive a 12V voltage and convert the 12V voltage to +5V or +3.3V.

[0023] The output of the power conversion module is coupled to the power input of the main control module.

[0024] In some embodiments, the power conversion module includes a first conversion module and a second conversion module.

[0025] The first conversion module is used to receive a 12V voltage and convert the 12V voltage to a +5V voltage.

[0026] The input terminal of the second conversion module is connected to the output terminal of the first conversion module, and is used to receive the +5V voltage and convert the +5V voltage into a +3.3V voltage output.

[0027] In some embodiments, the second conversion module includes at least a constant voltage transformer, the input terminal of which is coupled to the output terminal of the first conversion module.

[0028] The output terminal of the constant voltage transformer is connected to the power input terminal of the main control module.

[0029] In some implementations, an SWD debugging interface module is also included, wherein the power input terminal of the SWD debugging interface module is connected to the output terminal of the constant voltage transformer.

[0030] One signal terminal of the SWD debugging interface module is connected to one signal terminal of the main control module.

[0031] In some embodiments, a reset module is also included, wherein the power input terminal of the reset module is connected to the output terminal of the constant voltage transformer.

[0032] One signal terminal of the reset module is connected to the reset terminal of the main control module.

[0033] In some implementations, an external crystal module is also included, one end of which is connected to a crystal oscillator terminal of the main control module.

[0034] The other end of the external crystal module is connected to the other crystal oscillator of the main control module.

[0035] The automotive rearview mirror heating trigger module of this utility model includes a capacitive sensor for acquiring an electrical threshold formed on the glass mirror when it is wet or dry, and a main control module. The main control module is used to acquire the electrical threshold formed by the capacitive sensor. When the main control module detects an increase in the electrical threshold, it outputs a PWM signal to control the heater to heat the glass mirror. The main control module is used to detect the temperature value of the glass mirror. When the temperature value reaches a preset value, the main control module adjusts the duty cycle of the PWM signal to control the temperature value of the glass mirror. Compared to existing technologies, this method involves installing a capacitive sensor on the inside of the rearview mirror glass. The sensor and the glass form a large capacitor. When the rearview mirror glass surface is dry, the capacitance value is constant. When raindrops are present on the outside of the rearview mirror, the rainwater changes the capacitance value. At this time, the main control module can activate the glass heating based on the change in capacitance value, causing the moisture on the glass surface to evaporate quickly, thereby restoring the glass to clear. This effectively solves the problem that humidity sensors are often installed inside the vehicle, and even when installed inside the rearview mirror housing, the triggering effect is often limited because airflow does not easily enter the vehicle or rearview mirror housing during vehicle operation. Attached Figure Description

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments. In the accompanying drawings:

[0037] Figure 1 This is a circuit schematic diagram of an embodiment of the power conversion module provided by this utility model;

[0038] Figure 2This is a circuit schematic diagram of an embodiment of the main control module provided by this utility model;

[0039] Figure 3 This is a circuit schematic diagram of an embodiment of the SWD debugging interface module, reset module, and external crystal module provided by this utility model;

[0040] Figure 4 This is a structural diagram of an embodiment of the capacitive sensor provided by this utility model. Detailed Implementation

[0041] To provide a clearer understanding of the technical features, objectives, and effects of this utility model, the specific embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0042] like Figures 1-4 As shown, in the first embodiment of the automotive rearview mirror heating trigger module of this utility model, the automotive rearview mirror heating trigger module includes a power conversion module (110, 120), a main control module 130, an SWD debugging interface module 140, a reset module 150, and an external crystal module 160.

[0043] Among them, the power conversion modules (110, 120) have the functions of step-down / voltage regulation / filtering, and are used to convert the voltage input to the battery pack. For example, they can convert the +12V voltage to +5V or +3.3V (corresponding to VDD) voltage and output it to the subsequent circuit.

[0044] The main control module 130 performs logic operations, signal reception, signal comparison and processing, and outputs PWM signals and control signals.

[0045] The main control module 130 is equipped with temperature threshold and humidity threshold;

[0046] The SWD debug interface module 140 is used for asynchronous data transmission between the host and the target device, which is achieved through two lines (SWCLK and SWDIO).

[0047] The reset module 150 can implement the initialization settings of the main control module 130 when it starts up through hardware circuits or software instructions, including clearing memory contents and configuring hardware parameters, so as to provide a stable state for the operation of the main control module 130.

[0048] The external crystal module 160 provides a stable and accurate clock signal to the system of the main control module 130, ensuring that all parts of the system operate synchronously.

[0049] The capacitive sensor 200 is used to detect water vapor / droplets on the glass lens. For example, when the capacitive sensor 200 is closely attached to the rearview mirror glass, and there are water stains on the glass surface, since the dielectric constant of water is 80 and the dielectric constant of glass is generally between 5 and 10, the water vapor / droplets will change the capacitance value of the glass metal mesh, thereby increasing the detection value of the capacitive sensor 200.

[0050] Specifically, the capacitive sensor 200 is attached to the rearview mirror glass to obtain the electrical threshold formed on the glass when it is wet or dry, and outputs the obtained electrical threshold to the main control module 130.

[0051] Furthermore, the signal terminal of the main control module 130 is connected to the signal terminal of the capacitance sensor 200 to obtain the electrical threshold formed by the capacitance sensor 200, and output at least two PWM signals according to the feedback electrical threshold.

[0052] When the main control module 130 detects an increase in the electrical threshold, it outputs at least two PWM signals to control the heater to heat the glass mirror, thereby evaporating the water vapor / droplets on the glass mirror.

[0053] Meanwhile, the main control module 130 is used to detect the temperature value of the glass mirror. When the temperature value of the glass mirror reaches the preset value, the main control module 130 adjusts the duty cycle of the PWM signal to control the temperature value of the glass mirror, so that the temperature of the glass mirror is in a relatively constant state.

[0054] Using this technical solution, a capacitive sensor 200 is installed on the inner side of the rearview mirror glass. The sensor and the rearview mirror glass form a large capacitor. When the rearview mirror glass surface is dry, the capacitance value is constant. When there is water mist / raindrops on the outer side of the rearview mirror, the rainwater changes the capacitance value. At this time, the main control module 130 can activate the glass heating according to the change in capacitance value, so that the moisture on the glass surface evaporates quickly, thereby restoring the glass to clarity. This effectively solves the problems of manual operation not being able to automatically activate, which is inconvenient and results in a poor user experience.

[0055] Temperature and humidity sensors have a high startup threshold, making them difficult to activate when it rains, resulting in a poor user experience.

[0056] In some implementations, such as Figure 4 As shown, to ensure the reliability of obtaining the rearview mirror electrical threshold, an upper electrode 201, an isolation layer 202, and a lower electrode 203 can be provided in the capacitive sensor 200.

[0057] The upper electrode 201, the isolation layer 202 and the lower electrode 203 are stacked in sequence.

[0058] The upper electrode 201 is a metal mesh.

[0059] The insulating layer 202 is a polyimide film that separates the two electrodes of the capacitor.

[0060] The lower electrode 203, serving as an internal electrode of the sensor, is the reference terminal of the capacitor.

[0061] Specifically, the upper electrode 201 is tightly attached to the rearview mirror glass. When there are water stains / drops on the glass surface, since the dielectric constant of water is 80 and the dielectric constant of glass is generally between 5 and 10, the water stains / drops will change the capacitance value of the upper electrode 201 set inside the glass, thereby increasing the detection value of the capacitance sensor.

[0062] The basic formula for capacitance is: ;

[0063] As ε increases, the capacitance C also increases;

[0064] Specifically, the upper electrode 201 is positioned at the top to acquire the electrical threshold formed on the glass mirror due to wetness or dryness.

[0065] An insulating layer 202 is disposed on the lower end face of the upper electrode 201 for dielectric or insulating purposes.

[0066] The lower electrode 203 is disposed on the lower end face of the isolation layer 202 and cooperates with the upper electrode 201 to form a signal sensing.

[0067] Specifically, PTA0 (left rearview mirror) and PTA1 (right rearview mirror) of the main control module 130 are ADC sampling ports for capacitance values;

[0068] PTA2 and PTA3 are the sampling ADC interfaces for the glass temperature sensors of the left and right rearview mirrors, respectively.

[0069] PTC2 and PTC3 are the WPM control ports for the heater, respectively.

[0070] The main control module 130 collects the voltage of the capacitor sensor 200 port through PTA0 and PTA1. When the detected capacitance value increases to the threshold, it outputs a PWM signal to control the heater to heat up.

[0071] When the capacitance value of the capacitive sensor 200 increases, the duty cycle of the PWM is adjusted to increase.

[0072] Meanwhile, PTA2 and PTA3 monitor the temperature of the glass surface to keep the temperature of the left and right rearview mirrors below 60°C.

[0073] In some implementations, such as Figure 1As shown, to ensure the reliability of the main control module 130, a power conversion module (110, 120) can be set in the trigger module. The power conversion module (110, 120) is used to convert the input voltage.

[0074] Specifically, the input terminal of the power conversion module (corresponding to 110) is used to receive a 12V voltage and convert the 12V voltage to +5V or +3.3V.

[0075] The output of the power conversion module (corresponding to 120) is coupled to the power input of the main control module 130, inputting +3.3V voltage (corresponding to VDD) into the main control module 130 to provide working power for its operation.

[0076] In some embodiments, the power conversion modules (110, 120) include a first conversion module 110 and a second conversion module 120.

[0077] Specifically, the first conversion module 110 is used to receive a 12V voltage and convert the 12V voltage to a +5V voltage.

[0078] The input terminal of the second conversion module 120 is connected to the output terminal of the first conversion module 110, and is used to receive +5V voltage and convert +5V voltage to +3.3V voltage output.

[0079] In some implementations, such as Figure 1 As shown, the second conversion module 120 includes at least one constant voltage transformer U3, which has bidirectional filtering function and good anti-interference ability;

[0080] Specifically, the input terminal (corresponding to pin 1) of the constant voltage transformer U3 is coupled to the output terminal (corresponding to the P5V-LDO terminal) of the first conversion module 110 to receive +5V voltage.

[0081] The enable terminal (corresponding to pin 3) of the constant voltage transformer U3 is connected to the output terminal (corresponding to P5V-LDO terminal) of the first conversion module 110 through the first resistor R1.

[0082] The output terminal (corresponding to pin 5) of the constant voltage transformer U3 is connected to the power input terminal of the main control module 130 to provide a +3.3V voltage to the main control module 130.

[0083] In some implementations, such as Figure 1 As shown, the first conversion module 110 also includes a first capacitor C1, a forward low-dropout regulator U1, a second capacitor C2, and a third capacitor C3.

[0084] The first capacitor C1 filters the voltage signal input from the previous stage, and then inputs it to the input terminal (pin 3) of the positive low-dropout regulator U1 for voltage reduction.

[0085] The voltage output from the positive low-dropout regulator U1 is filtered by the second capacitor C2 and the third capacitor C3 connected in parallel, and then output to the input terminal (pin 1) and the enable terminal (pin 3) of the constant voltage transformer U3.

[0086] In some implementations, such as Figure 3 As shown, to ensure the reliability of signal interaction between the main control module 130 and external devices, an SWD debugging interface module 140 can be set in the trigger module. The power input terminal (corresponding to pin 2) of the SWD debugging interface module 140 is connected to the output terminal (corresponding to +3.3V) of the constant voltage transformer U3.

[0087] A signal terminal (corresponding to pins 3 and 8) of the SWD debugging interface module 140 is connected to a signal terminal (corresponding to pins 55 and 56) of the main control module 130, so as to load the external input signal to the main control module 130.

[0088] In some implementations, such as Figure 3 As shown, to ensure the stability of the main control module 130 during operation, a reset module 150 can be set in the trigger module. The power input terminal (corresponding to VDD) of the reset module 150 is connected to the output terminal (corresponding to +3.3V) of the constant voltage transformer U3.

[0089] One signal terminal (corresponding to RESET-n) of the reset module 150 is connected to the reset terminal (corresponding to pin 63) of the main control module 130 through the seventh resistor R7. When the reset module 150 is triggered, the initialization settings of the main control module 130 at startup can be realized.

[0090] In some implementations, such as Figure 3 As shown, to ensure the stability of the main control module 130, an external crystal module 160 can be set in the trigger module. One end of the external crystal module 160 (corresponding to PTB6) is connected to a crystal oscillator terminal (corresponding to pin 12) of the main control module 130.

[0091] The other end of the external crystal module 160 (corresponding to PTB7) is connected to the other crystal oscillator terminal (corresponding to pin 11) of the main control module 130. The pulse clock signal generated by the external crystal module 160 when it is working is input to the main control module 130 through the signal terminals (corresponding to PTB6 and PTB7) to provide it with a stable and accurate clock signal.

[0092] The embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of the present invention without departing from the spirit and scope of the claims. All of these forms are within the protection scope of the present invention.

Claims

1. A heating trigger module for a car rearview mirror, characterized in that, have: A capacitive sensor, which is attached to the rearview mirror glass, is used to obtain the electrical threshold formed on the glass mirror when it is wet or dry. The main control module has its signal terminal connected to the signal terminal of the capacitance sensor, and is used to obtain the electrical threshold formed by the capacitance sensor. When the main control module detects an increase in the electrical threshold, it outputs a PWM signal to control the heater to heat the glass mirror. The main control module is used to detect the temperature value of the glass mirror. When the temperature value reaches a preset value, the main control module adjusts the duty cycle of the PWM signal to control the temperature value of the glass mirror.

2. The automotive rearview mirror heating trigger module according to claim 1, characterized in that, The capacitive sensor includes at least an upper electrode, an isolation layer, and a lower electrode stacked together. The upper electrode is positioned at the top to acquire the electrical threshold formed on the glass mirror when it is wet or dry. The insulating layer is disposed on the lower end face of the upper electrode and serves as a dielectric or insulating layer. The lower electrode is disposed on the lower end face of the isolation layer and cooperates with the upper electrode to form a signal sensing.

3. The automotive rearview mirror heating trigger module according to claim 1, characterized in that, It also includes a power conversion module, whose input terminal is used to receive a 12V voltage and convert the 12V voltage to +5V or +3.3V. The output of the power conversion module is coupled to the power input of the main control module.

4. The automotive rearview mirror heating trigger module according to claim 3, characterized in that, The power conversion module includes a first conversion module and a second conversion module. The first conversion module is used to receive a 12V voltage and convert the 12V voltage to a +5V voltage. The input terminal of the second conversion module is connected to the output terminal of the first conversion module, and is used to receive the +5V voltage and convert the +5V voltage into a +3.3V voltage output.

5. The automotive rearview mirror heating trigger module according to claim 4, characterized in that, The second conversion module includes at least one constant voltage transformer, the input terminal of which is coupled to the output terminal of the first conversion module. The output terminal of the constant voltage transformer is connected to the power input terminal of the main control module.

6. The automotive rearview mirror heating trigger module according to claim 5, characterized in that, It also includes an SWD debugging interface module, the power input terminal of which is connected to the output terminal of the constant voltage transformer. One signal terminal of the SWD debugging interface module is connected to one signal terminal of the main control module.

7. The automotive rearview mirror heating trigger module according to claim 6, characterized in that, It also includes a reset module, the power input terminal of which is connected to the output terminal of the constant voltage transformer. One signal terminal of the reset module is connected to the reset terminal of the main control module.

8. The automotive rearview mirror heating trigger module according to claim 7, characterized in that, It also includes an external crystal module, one end of which is connected to a crystal oscillator terminal of the main control module. The other end of the external crystal module is connected to the other crystal oscillator of the main control module.

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