EC mirror control device with normally closed power-off protection

Abstract

This utility model belongs to the field of vehicle rearview mirror control technology, specifically disclosing an EC rearview mirror control device with normally closed power-off protection, including: a first voltage conversion module and a second voltage conversion module, the output terminal of the first voltage conversion module being connected to one electrode of the electrochromic device in the EC rearview mirror, and the output terminal of the second voltage conversion module being connected to the other electrode of the electrochromic device; a control module, connected to the control terminals of the first and second voltage conversion modules respectively; a normally closed switch, connected between the output terminals of the first and second voltage conversion modules; the normally closed switch is also electrically connected to the control module; and a light sensor unit, electrically connected to the control module. It has the following advantages: automatic short-circuiting for rapid fading upon power failure; mutually exclusive unidirectional drive to prevent loss; and zero-voltage microamplitude low power consumption in standby mode.

Description

Technical Field

[0001] This utility model relates to the field of vehicle rearview mirror control technology, and more specifically, to an EC (Electrochromic) rearview mirror control device with normally closed power-off protection. Background Technology

[0002] Existing EC (Extra-Layer Anti-Glare) rearview mirror control devices generally use electronic control to achieve mirror tinting and fading. When a vehicle behind turns on its high beams at night, causing glare to the driver, the anti-glare rearview mirror darkens under the control circuit's operation, reducing the intensity of reflected light and minimizing glare to ensure clear visibility for the driver. When the glare disappears or diminishes, the anti-glare rearview mirror fades by reducing voltage or cutting off power, returning to normal operation. Current EC rearview mirror control devices mainly suffer from the following problems:

[0003] On the one hand, in emergency scenarios where the vehicle loses power unexpectedly, the anti-glare rearview mirror can only restore the mirror surface through natural fading. The fading speed is slow and cannot guarantee the driver's clear rear view in time, which poses a safety risk.

[0004] On the other hand, some existing solutions use reverse power connection to achieve rapid fading, which can easily lead to a decline in device performance, insufficient reliability and stability, and a shortened device lifespan with long-term use.

[0005] Meanwhile, existing control circuits generally have high standby power consumption, which makes it difficult to meet the requirements of energy saving and long-term stable operation of automotive electrical systems.

[0006] To address this issue, an EC rearview mirror control device with normally closed power-off protection is proposed. Utility Model Content

[0007] The present invention aims to provide an EC rearview mirror control device with normally closed power-off protection to solve or improve the existing EC rearview mirror control devices mentioned above, which are unable to fade quickly when the vehicle is powered off, are prone to damage to components when connected to reverse power, and have high power consumption, making it difficult to simultaneously meet the technical requirements of safety, reliability and low power consumption.

[0008] In view of this, the first aspect of the present invention is to provide an EC rearview mirror control device with normally closed power-off protection.

[0009] The first aspect of this utility model provides an EC rearview mirror control device with normally closed power-off protection, comprising: a first voltage conversion module and a second voltage conversion module, wherein the output terminal of the first voltage conversion module is connected to one electrode of an electrochromic device in the EC rearview mirror, and the output terminal of the second voltage conversion module is connected to the other electrode of the electrochromic device; a control module, connected to the control terminals of the first voltage conversion module and the second voltage conversion module respectively; the control module is used to control the output voltage of the first voltage conversion module and the second voltage conversion module; a normally closed switch, connected between the output terminals of the first voltage conversion module and the second voltage conversion module; the normally closed switch is also electrically connected to the control module, and when the normally closed switch is in a closed state, the normally closed switch short-circuits the two electrodes of the electrochromic device; a light sensor unit, electrically connected to the control module; the light sensor unit is used to detect and acquire light intensity signals, and the control module controls the opening and closing state of the normally closed switch according to the light intensity signals.

[0010] In any of the above technical solutions, when the difference in light intensity signal detected by the optical sensor unit reaches or exceeds a set threshold, the control module outputs a drive signal to make the normally closed switch open; and the following situations exist: Situation 1: The first voltage conversion module outputs a non-zero voltage, and the second voltage conversion module outputs a zero voltage; or Situation 2: The second voltage conversion module outputs a non-zero voltage, and the first voltage conversion module outputs a zero voltage.

[0011] In any of the above technical solutions, the normally closed switch is a mechanical contact relay or a solid-state relay.

[0012] In any of the above technical solutions, the first voltage conversion module and the second voltage conversion module each include a low dropout linear regulator, and the output voltage range of the first voltage conversion module and the second voltage conversion module is 0.3V to 2.0V.

[0013] In any of the above technical solutions, the light sensor unit includes a first light sensor and a second light sensor, and the control module controls the opening and closing state of the normally closed switch according to the light intensity difference detected by the first light sensor and the second light sensor; the first light sensor is disposed on the front of the rearview mirror and is used to detect the ambient light intensity around the rearview mirror; the second light sensor is disposed on the back of the rearview mirror and is used to detect the light intensity behind the rearview mirror.

[0014] In any of the above technical solutions, the EC rearview mirror control device further includes an indicator light: the indicator light is electrically connected to the control module, and the on / off state of the indicator light is related to the working state of the EC rearview mirror.

[0015] In any of the above technical solutions, the EC rearview mirror control device further includes a manual switch: the manual switch is electrically connected to the control module and is used to manually switch the working state of the EC rearview mirror.

[0016] In any of the above technical solutions, when the control module does not output a drive signal and / or when the control module is powered off, the normally closed switch is in a closed state, and the two electrodes of the electrochromic device are short-circuited.

[0017] The beneficial effects of this utility model compared with the prior art are as follows:

[0018] The normally closed switch remains closed when the control module loses its drive or the vehicle loses power. The two electrodes of the electrochromic device are short-circuited by low resistance, and the residual charge inside is immediately discharged, so that the lens automatically returns to a high-transmittance state within a few seconds. Compared with the existing solution that relies solely on the natural fading of the lens when the circuit is broken, it can ensure the driver's rear visibility more quickly in an emergency.

[0019] The control module implements mutual exclusion control for the first and second voltage conversion modules: at any given time, only one output is allowed to output a non-zero voltage, while the other remains at zero voltage. The lens is always subjected to a unidirectional electric field, eliminating material degradation caused by simultaneous bipolar voltage application or reverse overvoltage, and significantly improving the long-term reliability and stability of the electrochromic device.

[0020] When there is no glare or the vehicle is stationary, both voltage conversion modules are at zero voltage output. The normally closed switch provides a pure hardware short circuit, without the need to maintain any bias current. The static current of the whole unit drops to the microamp level, meeting the low power consumption requirements of modern vehicles.

[0021] Additional aspects and advantages of embodiments of the present invention will become apparent in the following description or may be learned by practice of embodiments of the present invention. Attached Figure Description

[0022] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0023] Figure 1 This is a logic block diagram of the control structure of this utility model;

[0024] Figure 2 This is a front view of the EC rearview mirror of this utility model;

[0025] Figure 3 This is a rear view of the EC rearview mirror of this utility model.

[0026] in, Figure 1-3 The correspondence between the reference numerals and component names in the attached drawings is as follows:

[0027] 1 First voltage conversion module, 101 First output terminal, 2 Second voltage conversion module, 201 Second output terminal, 3 Control module, 4 Normally closed switch, 5 Vehicle power supply, 6 EC rearview mirror, 7 Indicator light, 8 Manual switch, 9 First light sensor, 10 Second light sensor. Detailed Implementation

[0028] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0029] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited to the specific embodiments disclosed below.

[0030] Please see Figure 1-3 The following describes an EC rearview mirror control device with normally closed power-off protection according to some embodiments of the present invention.

[0031] An embodiment of the first aspect of this utility model provides an EC rearview mirror control device with normally closed power-off protection. In some embodiments of this utility model, such as... Figure 1-3 As shown, the EC rearview mirror control device includes:

[0032] The first voltage conversion module 1 and the second voltage conversion module 2 are connected. The output of the first voltage conversion module 1 is connected to one electrode of the electrochromic device in the EC rearview mirror 6, and the output of the second voltage conversion module 2 is connected to the other electrode of the electrochromic device.

[0033] The control module 3 is connected to the control terminals of the first voltage conversion module 1 and the second voltage conversion module 2 respectively; the control module 3 is used to control the output voltage of the first voltage conversion module 1 and the second voltage conversion module 2.

[0034] Normally closed switch 4 is connected between the first output terminal 101 of the first voltage conversion module 1 and the second output terminal 201 of the second voltage conversion module 2; normally closed switch 4 is also electrically connected to control module 3. When normally closed switch 4 is in the closed state, normally closed switch 4 short-circuit the two electrodes of electrochromic device.

[0035] The light sensor unit is electrically connected to the control module 3; the light sensor unit is used to detect and acquire light intensity signals, and the control module 3 controls the opening and closing state of the normally closed switch 4 according to the light intensity signals.

[0036] This utility model provides an EC rearview mirror 6 control device with normally closed power-off protection, specifically including: a first voltage conversion module 1, a second voltage conversion module 2, a control module 3, a normally closed switch 4, and a light sensor unit, used to realize closed-loop drive of the electrochromic control of the rearview mirror, which can ensure the reliable anti-glare function of the rearview mirror in both normal and power-off states.

[0037] The first voltage conversion module 1 and the second voltage conversion module 2 are respectively connected to the two terminals of the electrochromic device in the EC rearview mirror 6, serving as a direct output path for applying control voltage to the electrochromic device. Preferably, the first voltage conversion module 1 and the second voltage conversion module 2 integrate a multi-level voltage control unit and a switching matrix circuit, which can output multi-level stable voltage signals, such as 0.6V, 0.8V, 1.0V, 1.2V, and 1.4V, under the drive of the control module 3. These signals are used to drive the electrochromic device to achieve different degrees of coloration, thereby controlling the mirror reflectivity and improving driving comfort and safety under strong rear glare.

[0038] The first voltage conversion module 1 and the second voltage conversion module 2 do not output non-zero voltages simultaneously. Instead, they are mutually exclusive controlled by the control module 3. That is, if the first voltage conversion module 1 outputs the specified operating voltage at any given time, the second voltage conversion module 2 will automatically be in a zero-voltage or high-impedance output state; and vice versa. This effectively prevents irregular voltage superposition or conflict between the two poles of the electrochromic device, improving the overall system reliability in terms of both circuit stability and device lifespan.

[0039] Normally closed switch 4 is connected between the first output terminal 101 of the first voltage conversion module 1 and the second output terminal 201 of the second voltage conversion module 2, and is electrically connected to the control module 3. When the control module 3 does not output a control signal, normally closed switch 4 remains closed, either in a power-off or standby state, short-circuiting the two ends of the electrochromic device to form a closed loop, thus accelerating its fading process. Once strong light interference is detected from behind or the control module 3 enters its working state, normally closed switch 4 switches to the open state under the drive signal of the control module 3, allowing the output voltages of the first voltage conversion module 1 and the second voltage conversion module 2 to be independently applied to the electrochromic device, thereby driving it into the colored state and achieving the anti-glare function. Even when the vehicle is powered off or the control system malfunctions, the EC device can still automatically and quickly return to the high-transmittance state, effectively preventing the driver's field of vision from being limited due to continuous tinting of the mirror.

[0040] The light sensor unit collects light intensity signals and feeds them back to the control module 3. The control module 3 dynamically judges the light intensity signals. If the light intensity exceeds the set threshold, it is considered that there is obvious glare interference from behind. Then, it outputs a control signal to open the normally closed switch 4 and drives the voltage conversion module to output the corresponding voltage value to adjust the color depth of the EC device.

[0041] In summary, the normally closed switch 4 automatically closes and momentarily short-circuits the two poles of the EC lens when the control module 3 loses power or malfunctions. The lens fading process no longer relies on power supply but fades automatically through the shortest charge release path. Compared with natural open-circuit fading, the lens recovery time can be shortened by several times, ensuring that clear rear vision can be quickly restored even in the event of a sudden power outage. In the non-operating state, the two voltage conversion modules simultaneously enter a zero-voltage / high-resistance state, and the system is in a pure hardware short-circuit maintenance mode. The standby current is reduced to almost the level of the relay coil leakage current, which effectively reduces the battery load compared to traditional solutions that require maintaining a maintenance voltage or reverse drive. The control module 3 uses mutual exclusion logic to ensure that only one voltage is applied to the electrochromic device at any given time, and the two poles are never under voltage at the same time, eliminating reverse voltage superposition and irregular potential jumps. At the same time, it eliminates the reverse-connection fading method, avoiding reverse coloring and material decomposition phenomena in small molecule EC devices, fundamentally improving the reliability and service life of the lens.

[0042] Specifically, the control module 3, the first voltage conversion module 1, and the second voltage conversion module 2 are electrically connected to the vehicle power supply 5.

[0043] In any of the above embodiments, when the difference in light intensity signals detected by the light sensor unit reaches or exceeds a set threshold, the control module 3 outputs a drive signal to put the normally closed switch 4 in an open state; and the following situations apply.

[0044] Scenario 1: The first voltage conversion module 1 outputs a non-zero voltage, and the second voltage conversion module 2 outputs a zero voltage;

[0045] Scenario 2: The second voltage conversion module 2 outputs a non-zero voltage, while the first voltage conversion module 1 outputs a zero voltage.

[0046] In this embodiment, the light sensor unit continuously monitors the light intensity in front of and behind the rearview mirror. The control module 3 uses an STM32G071KBT6 microcontroller. When the difference in light intensity signals received by the control module 3 reaches or exceeds a set threshold, it identifies the presence of strong light interference from behind, thus entering the anti-glare requirement state. At this time, the control module 3 immediately outputs a drive signal, causing the normally closed switch 4 to change from its original closed state to its open state, cutting off the short circuit between the two poles of the electrochromic device, thereby putting the lens into a controlled drive state. In the drive state, one of the following two scenarios is selected for operation based on the specific judgment result:

[0047] If scenario one is determined, the first voltage conversion module 1 starts to output a preset non-zero voltage, such as 0.8 volts, 1.0 volts, or 1.2 volts, while the second voltage conversion module 2 maintains the output of zero voltage;

[0048] If the case is determined to be scenario two, then the second voltage conversion module 2 outputs a non-zero voltage, while the first voltage conversion module 1 maintains a zero voltage output.

[0049] When the light intensity difference decreases and falls below the threshold, control module 3 cancels the drive signal, causing normally closed switch 4 to automatically reopen. The two electrodes of the electrochromic device are then short-circuited again, thus achieving rapid fading and entering a low-power standby state. The entire switching process is fast and stable, meeting the vehicle's automatic anti-glare requirements at night or under complex lighting conditions.

[0050] In any of the above embodiments, the normally closed switch 4 is a mechanical contact relay or a solid-state relay.

[0051] In a preferred embodiment, the normally closed switch 4 is a mechanical contact relay of model G6A-234P-ST-US. The normally closed contacts of this relay remain closed when the device is powered on and the control module 3 is not outputting a drive signal, forming a very low-impedance short circuit between the two poles of the electrochromic device, allowing the device to fade at the fastest speed. When the light intensity difference reaches a threshold, the control module 3 applies a drive pulse of approximately 12 volts to the relay coil through an NPN transistor, resulting in a coil current of approximately 35 mA. After the armature is attracted, the normally closed contacts open, the two poles of the lens are separated, and then the first or second voltage conversion module 2 applies the corresponding operating voltage according to mutual exclusion logic.

[0052] In another preferred embodiment, the normally closed switch 4 is a solid-state relay of model AQY210S, which internally consists of a light-emitting diode, an optocoupler, and a dual-channel field-effect transistor. When power is off, both field-effect transistors are in the conducting state, with an equivalent on-resistance of approximately two ohms, providing a reliable short-circuit path for the electrochromic device; when the control module 3 injects approximately three milliamps of current into the internal light-emitting diode, the optocoupler is triggered, the dual-channel field-effect transistor is quickly turned off, and the normally closed switch 4 changes from closed to open, with a switching time of less than one millisecond.

[0053] In any of the above embodiments, the first voltage conversion module 1 and the second voltage conversion module 2 each include a low dropout linear regulator, and the output voltage range of the first voltage conversion module 1 and the second voltage conversion module 2 is 0.3V to 2.0V.

[0054] In a preferred embodiment, the first voltage conversion module 1 and the second voltage conversion module 2 each include an adjustable low-dropout linear regulator. The feedback terminal of the adjustable low-dropout linear regulator is connected to a voltage divider network via a digital potentiometer. By changing the resistance value of the digital potentiometer, the feedback voltage can be continuously adjusted between 0.3 volts and 2.0 volts. After the microcontroller selects the target voltage level based on the light difference, it writes the value to the register of the digital potentiometer, allowing the regulator to stably output the required voltage. When 0.8 volts is selected, the lens enters a light-colored state; when switched to 1.2 volts, the lens becomes darker.

[0055] In any of the above embodiments, the optical sensor unit includes a first optical sensor 9 and a second optical sensor 10, and the control module 3 controls the opening and closing state of the normally closed switch 4 according to the light intensity difference detected by the first optical sensor 9 and the second optical sensor 10.

[0056] The first light sensor 9 is located on the front of the rearview mirror and is used to detect the ambient light intensity around the rearview mirror.

[0057] The second light sensor 10 is located on the back of the rearview mirror and is used to detect the light intensity behind the rearview mirror.

[0058] In this embodiment, the light sensor unit employs two automotive-grade digital light sensors, OPT3001-Q1. The first light sensor 9 is fixed to the driver-facing panel of the rearview mirror glass, covering the combined environment in front of the vehicle and inside the cabin, and converts the current ambient light intensity into a lux value, which is then sent to the control module 3. The second light sensor 10 is mounted on the back of the rearview mirror, facing the oncoming traffic direction. Its optical window only receives rear-facing light, which is also sent to the control module 3 in the form of a digital lux value. The control module 3 calculates the difference in light intensity readings between the two sensors in real time. When the difference is less than a set threshold of 15 lx, the control module 3 keeps the drive pin of the normally closed switch 4 at a low level, the normally closed switch 4 is in a closed state, the two poles of the electrochromic device are shorted, and the lens remains highly transparent; if the difference is equal to or exceeds the threshold, the control module 3 immediately pulls the drive pin high, thereby opening the normally closed switch 4, and simultaneously wakes up the mutual exclusion voltage conversion module to output the corresponding voltage to drive the lens into the tinted state. As the strong light from behind weakens, the difference in light intensity decreases, control module 3 resets its drive pin, normally closed switch 4 closes again, and the lens quickly fades. The set threshold is typically 10–30 lux.

[0059] In any of the above embodiments, the EC rearview mirror 6 control device further includes an indicator light 7:

[0060] Indicator light 7 is electrically connected to control module 3, and the on / off state of indicator light 7 is related to the working state of EC rearview mirror 6.

[0061] In this embodiment, the indicator light 7 functions as a green LED and its series current-limiting resistor. The anode of the green LED is connected to a regulated power supply, and the cathode is connected to a programmable output port of the control module 3. When the control module 3 enters the anti-glare mode, it first sets the output port low, and the LED lights up after receiving current, allowing the driver to visually see that the rearview mirror is in tinted mode. When the light intensity difference decreases or the manual switch 8 returns the device to standby, the high level is pulled back to the output port, and the LED turns off, indicating that the lens has returned to high transmittance. Thus, the LED's on / off state is synchronized with the lens's working state, providing not only human-machine interface prompts but also facilitating maintenance personnel to visually determine whether the control circuit is functioning properly.

[0062] In any of the above embodiments, the EC rearview mirror 6 control device further includes a manual switch 8:

[0063] The manual switch 8 is electrically connected to the control module 3 and is used to manually switch the working state of the EC rearview mirror 6.

[0064] In this embodiment, the manual switching function of the manual switch 8 is realized through an automotive-grade waterproof tactile button, which is installed in the human-machine interaction area on the side edge of the rearview mirror housing. One end of the button is connected to the ground wire of the vehicle power supply 5, and the other end is connected to the control module 3 through a 100Ω series resistor.

[0065] In any of the above embodiments, when the control module 3 does not output a drive signal and / or when the control module 3 is powered off, the normally closed switch 4 is in a closed state, and the two electrodes of the electrochromic device are short-circuited.

[0066] In this embodiment, when the control module 3 no longer outputs a drive signal, or when the vehicle experiences an unexpected power outage that causes the control module 3 to lose its power supply, the normally closed switch 4 immediately remains or returns to its closed state. In both cases, the two electrodes of the electrochromic lens are directly short-circuited, and the residual charge inside the lens is rapidly released through a low-resistance path. The lens fades to a high-transmittance state within seconds, ensuring that the driver can still obtain a clear rear view when the vehicle experiences a sudden power outage. At the same time, the entire control device enters zero-power standby mode and no longer consumes vehicle power.

[0067] Furthermore, the first voltage conversion module 1 and / or the second voltage conversion module 2 have multiple selectable voltage levels, and the control module 3 is used to select different output voltage levels according to the difference in light intensity signals in order to control the coloring depth of the electrochromic device.

[0068] As described above, the first voltage conversion module 1 and the second voltage conversion module 2 use a low-dropout voltage regulator chip in conjunction with a digital potentiometer to form a multi-level voltage generation circuit. The feedback terminal of the low-dropout voltage regulator chip is connected to a fixed voltage divider network through the digital potentiometer. As long as the control module 3 outputs the corresponding serial data to the digital potentiometer, it can switch the feedback resistor value to a preset level, thereby allowing the voltage regulator chip to stably output four voltage levels: 0.8V, 1.0V, 1.2V, or 1.3V. The control module 3 continuously reads the values ​​of the two light sensors and calculates the difference: when the difference is in the range of 15 to 30 lux, the control module 3 writes the first level of data, the voltage regulator chip outputs 0.8V, and the lens is light-colored; when the difference rises to the range of 30 to 60 lux, the control module 3 writes the second level, outputs 1V, and the lens becomes darker; if the difference exceeds 60 lux, the highest level is written, outputting 1.2V to 1.3V, and the lens reaches the deepest color. With multiple voltage options, the device can finely subdivide the grayscale of the lens, making glare suppression and environmental transition smoother. At the same time, it keeps the voltage regulator chip working in the optimal linear range, ensuring that the output ripple is less than 10 millivolts, and avoiding stripes or flickering on the lens.

[0069] In the description of this utility model, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0070] The above embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of the present utility model. Any modifications and improvements made to the technical solutions of the present utility model by those skilled in the art without departing from the spirit of the present utility model should fall within the protection scope defined by the claims of the present utility model.

Claims

1. An EC mirror control device with normally closed power-off protection, characterized in that, include: A first voltage conversion module and a second voltage conversion module, wherein the output terminal of the first voltage conversion module is connected to one electrode of the electrochromic device in the EC rearview mirror, and the output terminal of the second voltage conversion module is connected to the other electrode of the electrochromic device; A control module is connected to the control terminals of the first voltage conversion module and the second voltage conversion module, respectively; the control module is used to control the output voltage of the first voltage conversion module and the second voltage conversion module. A normally closed switch is connected between the output terminal of the first voltage conversion module and the output terminal of the second voltage conversion module; the normally closed switch is also electrically connected to the control module, and when the normally closed switch is in the closed state, the normally closed switch short-circuit the two electrodes of the electrochromic device; A light sensor unit is electrically connected to the control module; the light sensor unit is used to detect and acquire light intensity signals, and the control module controls the opening and closing state of the normally closed switch according to the light intensity signals.

2. The EC mirror control device according to claim 1, characterized by When the difference in light intensity signal detected by the optical sensor unit reaches or exceeds a set threshold, the control module outputs a drive signal to put the normally closed switch in the open state; and the following situations apply. Scenario 1: The first voltage conversion module outputs a non-zero voltage, and the second voltage conversion module outputs a zero voltage; or Scenario 2: The second voltage conversion module outputs a non-zero voltage, and the first voltage conversion module outputs a zero voltage.

3. The EC mirror control device of claim 1, wherein The normally closed switch is a mechanical contact relay or a solid-state relay.

4. The EC mirror control device of claim 1, wherein The first voltage conversion module and the second voltage conversion module each include a low dropout linear regulator, and the output voltage range of the first voltage conversion module and the second voltage conversion module is 0.3V to 2.0V.

5. The EC mirror control device of claim 1, wherein The optical sensor unit includes a first optical sensor and a second optical sensor, and the control module controls the opening and closing state of the normally closed switch based on the light intensity difference detected by the first optical sensor and the second optical sensor. The first light sensor is disposed on the front of the rearview mirror and is used to detect the ambient light intensity around the rearview mirror; The second light sensor is located on the back of the rearview mirror and is used to detect the light intensity behind the rearview mirror.

6. The EC mirror control device of claim 1, wherein It also includes indicator lights: The indicator light is electrically connected to the control module, and the on / off state of the indicator light is related to the working state of the EC rearview mirror.

7. The EC mirror control device of claim 1, wherein It also includes a manual switch: The manual switch is electrically connected to the control module and is used to manually switch the working state of the EC rearview mirror.

8. The EC mirror control device of claim 1, wherein When the control module does not output a drive signal and / or when the control module is powered off, the normally closed switch is in a closed state, and the two electrodes of the electrochromic device are short-circuited.

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