CN110288935B - A kind of monitoring method and monitoring device of vehicle-mounted liquid crystal display backlight - Google Patents

Abstract

The invention relates to a monitoring method and a monitoring device for a backlight source of a vehicle-mounted liquid crystal display screen, wherein the method comprises the following steps: acquiring the service duration, the brightness information and the actual power value of the backlight source of the vehicle-mounted liquid crystal display screen; determining a corresponding calibration power value in a data calibration table of the vehicle-mounted liquid crystal display screen backlight source according to the service duration and the brightness information of the vehicle-mounted liquid crystal display screen backlight source, wherein the data calibration table is used for calibrating power calibration values which the backlight sources with different service durations should have when working with corresponding brightness information; and comparing the actual power value with the calibrated power value to determine whether the backlight source of the vehicle-mounted liquid crystal display screen is abnormal. According to the embodiment of the invention, the working condition of the vehicle-mounted liquid crystal display backlight source is monitored by detecting the power parameter of the vehicle-mounted liquid crystal display backlight source, the fault of the liquid crystal display screen caused by the aging of the vehicle-mounted liquid crystal display backlight source can be effectively avoided, the influence on the driving operation of a driver is avoided, and the driving safety is improved.

Description

A kind of monitoring method and monitoring device of vehicle-mounted liquid crystal display backlight

technical field

The invention relates to the technical field of intelligent vehicles, in particular to a monitoring method and a monitoring device for the backlight source of a vehicle-mounted liquid crystal display screen.

Background technique

With the development of automobile intelligence in recent years, especially the rapid development of new energy vehicles, LCD has become a very important electronic device in automobiles. , thin and low power consumption, and more and more data can be applied to the car LCD screen, for example, the car LCD screen can be used as a virtual instrument panel, and can also display entertainment audio and video information.

In the structural design of the LCD screen, the selection of the backlight source is very critical. The selected backlight source determines the power consumption, brightness, color and other optoelectronic parameters of the LCD screen, as well as the operating conditions and service life of the LCD screen. characteristic. Currently, commonly used backlight sources for liquid crystal display screens include electroluminescent light sources, linear light sources such as cold cathode fluorescent tubes, CCFLs, and LEDs.

The lifespan of a vehicle is related to its age and mileage. Before the vehicle is scrapped, the service life of the vehicle will generally exceed 10 years, or the mileage of the vehicle will generally reach hundreds of thousands of kilometers. However, as the use time of the vehicle LCD screen increases, the backlight device of the vehicle will age. The existing vehicle LCD display backlight source cannot meet the above-mentioned vehicle service life requirements, and the probability of problems in the vehicle use project increases. In the prior art, the vehicle-mounted system cannot monitor the backlight source of the vehicle-mounted LCD display, and the user cannot predict the use of the vehicle-mounted LCD display backlight in advance. handling of the vehicle.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned technical problem of inability to monitor the working condition of the vehicle-mounted LCD display backlight, the present invention provides a monitoring method and monitoring device for the vehicle-mounted LCD display backlight.

The monitoring method for the backlight source of the vehicle-mounted liquid crystal display screen includes the following steps:

Obtain the usage time, brightness information and actual power value of the backlight source of the vehicle LCD screen;

The corresponding calibration power value is determined in the data calibration table of the vehicle-mounted LCD display backlight according to the obtained usage time and brightness information of the vehicle-mounted LCD display backlight, wherein the data calibration table of the vehicle-mounted LCD display backlight uses The power calibration value that should have when calibrating the vehicle-mounted LCD display backlight of different use time with the corresponding brightness information;

Compare the actual power value and the calibration power value of the backlight source of the vehicle-mounted liquid crystal display screen to determine whether the backlight source of the vehicle-mounted liquid crystal display screen is abnormal.

Further, according to the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, a plurality of data calibration tables of the vehicle-mounted liquid crystal display screen backlight source are set,

The calibration power values of multiple calibration parameter data in each data calibration table have a uniform numerical threshold or numerical fluctuation range.

With the acceleration of the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, the numerical threshold or the numerical fluctuation range of the calibration power value of the multiple calibration parameter data in the corresponding data calibration table is increased.

Further, according to the aging rate of the vehicle-mounted liquid crystal display backlight, a data calibration table of the vehicle-mounted liquid crystal display backlight is provided,

With the acceleration of the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, the numerical threshold or the numerical fluctuation range of the calibration power value in the different calibration parameter data in the data calibration table is increased.

Further, before determining the corresponding calibration power value, the monitoring method further includes the steps:

establish and store a data calibration table for the vehicle LCD backlight source, and/or

Monitoring the usage time of the vehicle-mounted liquid crystal display backlight.

Further, according to the obtained use duration and brightness information of the vehicle LCD backlight, the calibration power value in the calibration parameter data with the same or similar use duration and brightness information is determined in the data calibration table of the vehicle LCD backlight. .

Further, use the preset brightness information to control the backlight source of the vehicle LCD display to emit light, obtain the working time of the vehicle LCD display backlight source in real time, and determine in the data calibration table of the vehicle LCD display backlight source to have the same or similar use time and brightness. the calibration power value in the calibration parameter data of the message; or,

When the preset use time of the vehicle-mounted liquid crystal display backlight source is reached, the vehicle-mounted liquid crystal display screen backlight source is monitored, so that the vehicle-mounted liquid crystal display screen backlight source emits light with preset brightness information.

Further, compare the actual power value and the calibration power value of the vehicle-mounted liquid crystal display backlight source, if the actual power value of the vehicle-mounted LCD display backlight source is within the range of the rated power value, then the current of the vehicle-mounted LCD display backlight source. The measured value and/or the measured voltage value is compared with the calibrated current value and the calibrated voltage value corresponding to the calibrated power value determined in the data calibration table to determine whether the vehicle LCD backlight source is abnormal.

Further, first compare the voltage measurement value of the vehicle LCD backlight with the calibration voltage value corresponding to the calibration power value determined in the data calibration table, when the voltage measurement value of the vehicle LCD backlight is at the calibration voltage value. When it is within the range, then compare the current measurement value of the vehicle LCD backlight source with the calibration current value corresponding to the calibration power value determined in the data calibration table.

On the other hand, the monitoring device for the backlight source of the vehicle LCD screen includes a voltage detection unit, a current detection unit and a monitoring unit, and the voltage detection unit and the current detection unit are respectively connected with the monitoring unit,

The voltage detection unit detects the voltage measurement value of the vehicle-mounted liquid crystal display screen backlight, and the current detection unit detects the current measurement value of the vehicle-mounted liquid crystal display screen backlight;

The monitoring unit obtains the use time and brightness information of the vehicle-mounted liquid crystal display backlight, and obtains the actual power value of the vehicle-mounted liquid crystal display backlight according to the voltage measurement value and the current measurement value; The use time and brightness information of the backlight source of the display screen determine the corresponding calibration power value in the data calibration table of the backlight source of the vehicle LCD screen, wherein the data calibration table of the backlight source of the vehicle LCD display screen is used to calibrate the vehicle-mounted LCD display screen backlight source with different durations. The power calibration value that the LCD backlight should have when working with the corresponding brightness information; compare the actual power value and the calibration power value of the vehicle LCD backlight to determine whether the vehicle LCD backlight is abnormal.

Further, the monitoring device for the backlight source of the vehicle-mounted liquid crystal display screen also includes a storage unit and a timing unit,

The storage unit stores the data calibration table of the backlight of the vehicle-mounted liquid crystal display screen,

The timing unit counts the usage time of the backlight source of the vehicle-mounted liquid crystal display screen, and stores the usage time data in the storage unit.

Further, according to the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, a plurality of data calibration tables of the vehicle-mounted liquid crystal display screen backlight source are set,

The calibration power values of multiple calibration parameter data in each data calibration table have a uniform numerical threshold or numerical fluctuation range.

With the acceleration of the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, the numerical threshold or the numerical fluctuation range of the calibration power value of the multiple calibration parameter data in the corresponding data calibration table is increased.

Further, the monitoring unit controls the backlight source of the vehicle-mounted liquid crystal display screen to emit light with preset brightness information, obtains the working time of the vehicle-mounted liquid crystal display screen backlight source in real time, and determines in the data calibration table of the vehicle-mounted liquid crystal display screen backlight source the same or similar. The calibrated power value in the calibration parameter data using duration and luminance information; or,

When the preset usage time of the vehicle-mounted LCD display backlight is reached, the monitoring unit monitors the vehicle-mounted LCD display backlight, so that the vehicle-mounted LCD display backlight emits light with preset brightness information.

Further, the monitoring unit compares the actual power value and the calibration power value of the vehicle-mounted liquid crystal display backlight source, if the actual power value of the vehicle-mounted LCD display backlight source is within the range of the rated power value, then the monitoring unit Compare the current measurement value and/or voltage measurement value of the vehicle LCD backlight source with the calibration current value and calibration voltage value corresponding to the calibration power value determined in the data calibration table, and determine the vehicle LCD display backlight source. Is it abnormal.

Further, the monitoring unit first compares the voltage measurement value of the vehicle-mounted LCD display backlight with the calibration voltage value corresponding to the calibration power value determined in the data calibration table. When the voltage measurement value of the vehicle-mounted LCD display backlight is at When the calibration voltage value is within the range, the monitoring unit compares the current measurement value of the vehicle LCD backlight source with the calibration current value corresponding to the calibration power value determined in the data calibration table.

Further, the voltage detection unit includes an operational amplifier, a capacitor, a switch, a first resistor Ra and a second resistor Rb, the non-inverting input terminal of the operational amplifier is grounded, and the inverting input terminal can be respectively connected to the first resistor Ra through the switch. The first end of the first resistor Rb and the first end of the second resistor Rb, the second end of the first resistor Ra is connected to the voltage Vin of the vehicle LCD backlight source, the second end of the second resistor Vb is connected to the reference voltage Vref, and the capacitor is connected to the operation Between the inverting input of the amplifier and the output Vout,

When the voltage detection unit detects the voltage of the vehicle-mounted liquid crystal display backlight, the switch connects the reverse input end of the operational amplifier to the first resistor Ra, and the voltage Vin of the vehicle-mounted liquid crystal display backlight is used to charge the integrating circuit, charging The time is Tu; then, the switch connects the inverting input terminal of the operational amplifier to the second resistor Rb, the integrating circuit discharges with the reference voltage Vref, and the discharge time is Td, then the voltage Vin of the vehicle LCD backlight is:

Vin=|−Vref((Ra/Rb)·(td/tu))|.

Beneficial effects of the present invention: The monitoring method and monitoring device for the backlight source of the vehicle-mounted liquid crystal display screen proposed by the embodiments of the present invention realize the detection of the current, voltage and power parameters of the vehicle-mounted liquid crystal display screen backlight source by detecting the current, voltage and power parameters of the vehicle-mounted liquid crystal display screen backlight source. Monitoring of working conditions can effectively avoid LCD display failures (for example, black screen) caused by the aging of the backlight source of the vehicle LCD display and abnormal circuit operation, avoid affecting the driving operation of the driver, and improve the driving safety.

Description of drawings

1 is a flowchart of a method for monitoring the backlight of a vehicle-mounted liquid crystal display screen proposed by an embodiment of the present invention;

2 is a flowchart of a method for monitoring the backlight source of a vehicle-mounted liquid crystal display screen provided by an embodiment of the present invention;

3 is a block diagram of a monitoring device for a vehicle-mounted liquid crystal display backlight provided by an embodiment of the present invention;

Fig. 4a, Fig. 4b are the circuit diagram and characteristic curve of the voltage detection unit of the monitoring device of the backlight source of the vehicle-mounted liquid crystal display screen proposed by the embodiment of the present invention;

FIG. 5 is a circuit diagram of a current detection unit of a monitoring device for a vehicle-mounted liquid crystal display backlight source according to an embodiment of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. However, those skilled in the art know that the present invention is not limited to the accompanying drawings and the following embodiments.

The embodiment of the present invention monitors the working condition of the backlight source of the vehicle-mounted liquid crystal display screen by monitoring the power of the backlight source of the vehicle-mounted liquid crystal display screen.

Specifically, the vehicle LCD backlight has its own design life. As the use time of the vehicle LCD backlight increases, the backlight will age, and the resistance of the backlight will gradually increase. In order to achieve the same brightness, the backlight The power consumption will increase; but within a certain period of use, the power consumed by the same backlight source is basically only related to the brightness of the backlight source, and is less affected by other factors, and is basically not affected by the ambient temperature (-40～ 85°C). Therefore, for the same backlight source, within a certain period of use, a data calibration table between brightness and power consumption can be established in advance, and whether the backlight source is faulty can be judged by looking up the table.

As shown in FIG. 1 , an embodiment of the present invention provides a method for monitoring the backlight source of a vehicle-mounted liquid crystal display screen, which includes the following steps:

S10: Establish a data calibration table between the brightness information of the vehicle-mounted liquid crystal display screen backlight and the power consumption.

For the specific type of vehicle LCD screen to be tested, based on the aging degree of the vehicle LCD display screen, a data calibration table between the brightness information of the vehicle LCD display screen backlight and the power consumption is established and stored. The data calibration table of the backlight source of the vehicle-mounted liquid crystal display screen is a collection of normal operating condition parameter data of the backlight source of the vehicle-mounted liquid crystal display screen.

The data calibration table of the vehicle LCD backlight source includes a plurality of calibration parameter data, and each calibration parameter data may include rated voltage value, rated current value, use time, brightness information, calibration current value, calibration voltage value and calibration power value.

The rated voltage value and rated current value are the rated power supply voltage value and rated power supply current value of the specific type of vehicle LCD display backlight under test, such as 12V/100mA, 24V/200mA, the specific type of vehicle LCD display screen under test If the backlight source can work under the conditions of different rated supply voltage and rated supply current, the corresponding settings must be made in the calibration parameter data. If it only works under the condition of a single rated supply voltage and rated supply current If it is under, it is not necessary to set it in the calibration parameter data.

The use time is the actual working time of the backlight of the vehicle LCD screen, which can be timed by the timing unit, and the use time can be stored in the storage part in real time, or the use time can be updated in the storage part when the vehicle LCD screen is turned off.

The brightness information can be the luminous brightness level of the tested specific type of vehicle LCD backlight, for example, can be set as a percentage of 0-100, or can be a specific brightness value (lumens).

The calibrated current value and the calibrated voltage value are based on the voltage value and current value ( The voltage value is associated with the current value). Each piece of calibration parameter data records the voltage value and current value of the tested specific type of vehicle-mounted LCD display backlight when it emits light with corresponding brightness information, and the calibrated current value and calibrated voltage value can be a specific numerical fluctuation range, It can also be a specific numerical value.

The calibrated power value is determined according to the calibrated current value and the calibrated voltage value, and is adapted to the values of the calibrated current value and the calibrated voltage value, and the calibrated power value may be a numerical value or a numerical fluctuation range.

Therefore, each calibration parameter data records that under the condition that rated current and voltage are applied to the backlight source of a specific type of vehicle LCD screen with different use time, when the vehicle LCD screen emits light with corresponding brightness information, the calibration should have. The current value and the calibration voltage value, and the calibration power value obtained based on the calibration current value and the calibration voltage value.

In Table 1, the data calibration table (including some calibration parameter data) of a vehicle-mounted LCD backlight source at a voltage rating of 12V and a current rating of 100mA is exemplarily shown:

Table 1

It can be seen from Table 1 that the same vehicle LCD backlight source may have the same nominal power value under different conditions, such as the serial number 3 and the serial number 20 in Table 1.

After analysis, for the vehicle LCD backlight source, when the use time is less than 5000 hours, the aging speed of the backlight source is very high and slow. Under the premise that the corresponding brightness information is certain, the actual power of the backlight source is basically unchanged. At this time, you can Ignore the change of the power value less than 5000 hours of use, or you can also set a smaller first value fluctuation range for the numerical fluctuation range of the calibrated power value in the calibration parameter data of less than 5000 hours of use, or, in the follow-up, the actual power When the value is compared with the value of the calibrated power value, a smaller first threshold value is set; when the use time is within 5000-10000 hours, the aging speed of the backlight source is accelerated. The actual power of the source will change to a certain extent. You can set a second numerical fluctuation range larger than the first numerical fluctuation range for the numerical fluctuation range of the calibrated power value in the calibration parameter data of the 5000-10000 hours of use, or, in the subsequent When comparing the actual power value with the value of the calibrated power value, set a second threshold value that is greater than the first threshold value; when the use time is greater than 10,000 hours, the backlight source will age faster. If the actual power of the backlight changes to a certain extent, a third numerical fluctuation range greater than the second numerical fluctuation range can be set for the numerical fluctuation range of the calibrated power value in the calibration parameter data whose use time is longer than 10,000 hours, or, in the subsequent When the power value is compared with the value of the calibrated power value, a third threshold value greater than the second threshold value is set. Therefore, according to the aging rate of the backlight source of the vehicle LCD screen, a plurality of data calibration tables of the vehicle LCD display backlight source can be established, and the calibration power value of the calibration parameter data of each data calibration table has a uniform numerical threshold value or The numerical fluctuation range, with the increase of the aging rate of the backlight source, the numerical threshold or numerical fluctuation range of the calibration power value of the calibration parameter data in the different data calibration tables increases.

In this embodiment, respectively corresponding to the usage duration of less than 5000 hours (slow aging degree), the usage duration of 5000-10000 hours (the aging degree is accelerated), and the usage duration of more than 10000 hours (the aging degree is faster), the establishment of the The three data calibration tables of the vehicle LCD backlight source correspond to different numerical thresholds or numerical fluctuation ranges respectively. As the aging rate of the backlight increases, the numerical thresholds or numerical fluctuation ranges increase.

Those skilled in the art can understand that even if only one data calibration table of the vehicle LCD backlight source is established, the threshold value or the numerical fluctuation range can be increased according to the acceleration of the aging rate of the backlight source.

S20: Acquire the usage duration, brightness information and actual power value of the vehicle-mounted liquid crystal display backlight source.

Obtain the usage time and brightness information of the vehicle-mounted liquid crystal display backlight source, detect the current measurement value and voltage measurement value of the vehicle-mounted liquid crystal display screen backlight source, and calculate the actual power value of the vehicle-mounted liquid crystal display screen backlight source.

Specifically, when the vehicle-mounted liquid crystal display backlight is working, it emits light with a certain brightness. When monitoring the working condition of the vehicle-mounted LCD display backlight, obtain the use time of the vehicle-mounted LCD display backlight and the brightness information related to the current brightness, and detect the current measurement value and voltage measurement value of the vehicle-mounted LCD display backlight source. , and based on the detected current measurement value and voltage measurement value, the actual power value of the vehicle LCD backlight source is obtained.

According to the monitoring request, the current measurement value and voltage measurement value of the vehicle LCD backlight source are detected under one brightness condition (based on one brightness information) to obtain the actual power value; it can also be under different brightness conditions (based on multiple brightness information) Detect the current measurement value and voltage measurement value of the vehicle LCD backlight source, and obtain multiple actual power values. Obtaining the current measurement value and voltage measurement value of the vehicle-mounted LCD display backlight under multiple brightness conditions is conducive to comprehensively monitoring the working conditions of the vehicle-mounted LCD display backlight. Wherein, the monitoring unit can use PWM signal to adjust the brightness information output to the vehicle-mounted LCD display backlight, that is, adjust the brightness information of the vehicle-mounted LCD display backlight through the PWM signal, and maintain the voltage of the vehicle-mounted LCD display backlight. Or the current remains unchanged, adjust the duty cycle of the PWM signal, and the backlight of the vehicle LCD screen flashes on and off. When the flashing frequency of the backlight source of the vehicle LCD screen exceeds a certain value, the human vision can only realize the change of the screen brightness. Long on-time results in high brightness, while short on-time results in low brightness.

Preferably, the monitoring of the backlight source of the vehicle LCD display screen is performed when the backlight source of the vehicle LCD display screen reaches a preset use time, and according to the monitoring request, the backlight source of the vehicle LCD display screen emits light with preset brightness information, and the vehicle LCD display screen backlight source emits light with preset brightness information. There are corresponding calibration parameter data in the data calibration table of the screen backlight. For example, as shown in Table 1, when the vehicle LCD backlight reaches 6200, 6400, 6600, 6800, 7000, 7200, 7400, and 7400 hours of use, the vehicle LCD backlight will operate at a preset brightness of 50%. It emits light and monitors the backlight of the vehicle LCD screen.

S30: Determine the corresponding calibration power value in the data calibration table of the backlight source of the vehicle-mounted liquid crystal display screen according to the obtained information on the usage time and brightness of the backlight source of the vehicle-mounted liquid crystal display screen.

According to the obtained usage duration and brightness information of the vehicle LCD backlight, the calibration power value in the calibration parameter data with the same or similar usage duration and brightness information is determined in the data calibration table of the vehicle LCD backlight.

In this step, preferably, the backlight source of the vehicle-mounted liquid crystal display screen is controlled to emit light with preset brightness information, the working time of the vehicle-mounted liquid crystal display screen backlight source is obtained in real time, and the monitoring of the vehicle-mounted liquid crystal display screen backlight source is performed. The calibration power value in the calibration parameter data with the same or similar usage duration and brightness information is determined in the data calibration table of the backlight source.

More preferably, when the preset use time of the vehicle-mounted LCD display backlight is reached, the vehicle-mounted LCD display backlight source is monitored, and the vehicle-mounted LCD display screen backlight source emits light with preset brightness information. There are corresponding calibration parameter data in the data calibration table. At this time, the same corresponding calibration power value can be directly found in the calibration parameter data of the data calibration table of the vehicle LCD backlight source.

In addition, since the monitoring of the backlight source of the vehicle LCD screen can be turned on from time to time, during monitoring, the usage time and brightness information of the current vehicle LCD display usually cannot be compared with the usage time in the calibration parameter data of the data calibration table. It corresponds exactly to the luminance information (same). Preferably, in the case where the obtained use duration and brightness information of the backlight source of the vehicle-mounted LCD screen cannot completely correspond to the use duration and brightness information in the calibration parameter data of the data calibration table, the vehicle-mounted liquid crystal display screen with the current vehicle-mounted LCD display The calibration power value is extracted from the calibration parameter data of the data calibration table whose actual use duration and brightness information are closer, among which the use duration is given priority. For example, the 2nd and 3rd items of calibration parameter data in Table 1 respectively list the calibrated power values of the backlight of the vehicle-mounted LCD screen for 6400 hours and 6600 hours of use under the condition of 50% brightness. If the actual use time of the current vehicle LCD screen under test is 6520 hours, when monitoring under 50% brightness conditions, since the actual use time of 6520 hours is closer to the use time of 6600 hours, the third item in Table 1 is extracted for calibration. The nominal power value in the parameter data.

S40: Compare the actual power value and the calibrated power value of the backlight source of the vehicle-mounted liquid crystal display screen, and determine whether the backlight source of the vehicle-mounted liquid crystal display screen is abnormal.

Compare the actual power value of the vehicle LCD backlight source with the determined calibration power value, if the actual power value of the vehicle LCD display backlight source is within the range of the extracted calibration power value (that is, the vehicle LCD display backlight source If the actual power value does not exceed the threshold range of the extracted calibration power value, or the actual power value of the vehicle LCD backlight is within the numerical fluctuation range of the extracted calibration power value), the vehicle LCD backlight Work in normal conditions, otherwise, the backlight of the vehicle LCD screen is in an abnormal state, and a sound or text alarm is issued.

In the above-mentioned method of the present invention, by comparing the actual power value of the backlight source of the vehicle-mounted liquid crystal display screen with the calibration power value in the corresponding calibration parameter data in the data calibration table, the normal working condition of the vehicle-mounted liquid crystal display screen backlight source can be monitored, It can effectively avoid the failure of the LCD screen caused by the aging of the backlight source of the vehicle LCD screen.

In addition, in the above method, when it is confirmed by monitoring the actual power value (aging degree) of the backlight source of the vehicle LCD display that the backlight source of the vehicle LCD display works under normal working conditions, the hardware circuit failure of the backlight source of the vehicle LCD display cannot be completely ruled out. It is possible that, for example, when individual LEDs in the LED matrix of the LED backlight are open-circuited, the actual power value may meet the requirements of the normal operating conditions, but the current measurement value and the voltage measurement value fluctuate beyond the normal operating conditions. In order to discover the circuit fault of the backlight source of the vehicle-mounted liquid crystal display screen in time, on the basis of comparing the power values in FIG. 1 , as shown in FIG. 2 , the monitoring method of the vehicle-mounted liquid crystal display screen backlight source in the embodiment of the present invention further includes step S50 :

S50: Compare the current measurement value and/or voltage measurement value of the vehicle-mounted LCD display backlight with the calibration current value and calibration voltage value corresponding to the calibration power value determined in the data calibration table, and determine the vehicle-mounted LCD display backlight Whether the source is abnormal.

Compare the current measurement value and/or voltage measurement value of the vehicle-mounted LCD display backlight with the calibration current value and the calibration voltage value in the calibration parameter data determined in step S30 to monitor the working condition of the vehicle-mounted LCD display backlight .

If the current measurement value of the vehicle LCD backlight exceeds the range of the calibration current value (that is, the current measurement value of the vehicle LCD backlight exceeds the threshold range of the value of the calibration current value, or the vehicle LCD backlight If the current measured value of the vehicle is not within the numerical fluctuation range of the calibrated current value), the on-board LCD backlight is in an abnormal state, and a sound or text alarm is issued; or, if the voltage measured value of the on-board LCD backlight exceeds the calibrated voltage value range (that is, the voltage measurement value of the vehicle LCD backlight exceeds the threshold range of the value of the calibrated voltage value, or the voltage measurement value of the vehicle LCD backlight is not within the numerical fluctuation range of the calibrated voltage value), then When the LCD backlight is in an abnormal state, a sound or text alarm is issued.

Preferably, first compare the voltage measurement value of the vehicle-mounted LCD display backlight with the voltage calibration value in the corresponding calibration parameter data with the same or similar use duration and brightness information in the data calibration table. The voltage measurement value is within the range of the calibration voltage value (that is, the voltage measurement value of the vehicle LCD backlight does not exceed the threshold range of the value of the calibration voltage value, or the voltage measurement value of the vehicle LCD backlight is within the calibration range. voltage value fluctuation range), then compare the current measurement value of the vehicle LCD backlight with the current calibration value in the corresponding calibration parameter data with the same or similar usage duration and brightness information in the data calibration table. The reason for this setting is that when there is a fault in the hardware circuit of the vehicle LCD backlight source, the voltage measurement value changes significantly, and the voltage change will inevitably lead to a current change, so there is no need to compare the current measurement values, and the vehicle can be directly determined. The LCD backlight is in an abnormal state.

In the above method of the present invention, by comparing the current measurement value and/or voltage measurement value of the vehicle-mounted LCD display backlight with the calibration current value and the calibration voltage value in the data calibration table, the vehicle-mounted LCD display backlight can be monitored. It can effectively avoid the failure of the LCD screen caused by the failure of the backlight source circuit of the vehicle LCD screen.

It should be noted that the above-mentioned method of the embodiment of the present invention can be applied to the start-up, operation and end of the vehicle-mounted liquid crystal display screen to monitor the working condition of the vehicle-mounted liquid crystal display screen backlight. It is a text message to prompt the driver. For example, the vehicle-mounted LCD display backlight can be monitored at the same brightness when the vehicle is switched on and off, and the operating time of the vehicle-mounted LCD display backlight can be updated after the vehicle-mounted LCD display finishes running.

According to another aspect of the present invention, an embodiment of the present invention provides a monitoring device for a vehicle-mounted liquid crystal display backlight, as shown in FIG. 3 , including a voltage detection unit, a current detection unit and a monitoring unit, a voltage detection unit and a current detection unit Connect to the monitoring unit respectively.

Specifically, the voltage detection unit detects the voltage measurement value of the vehicle-mounted LCD display backlight, and the current detection unit detects the current measurement value of the vehicle-mounted LCD display backlight.

In a preferred embodiment of the present invention, as shown in Figure 4a, the voltage detection unit includes an operational amplifier, a capacitor C, a switch, a first resistor Ra and a second resistor Rb. The non-inverting input terminal of the operational amplifier is grounded, and the inverting input terminal can be connected to the first terminal of the first resistor Ra and the first terminal of the second resistor Rb respectively through the switch, and the second terminal of the first resistor Ra is connected to the vehicle liquid crystal display. The voltage Vin of the screen backlight, the second terminal of the second resistor Vb is connected to the reference voltage Vref, and the capacitor C is connected between the inverting input terminal and the output terminal Vout of the operational amplifier.

When the voltage detection unit detects the voltage of the vehicle-mounted LCD display backlight, as shown in Figure 4b, the switch connects the reverse input end of the operational amplifier to the first resistor Ra, and the voltage Vin of the vehicle-mounted LCD display backlight is the integral The circuit is charged, and the charging time is counted as Tu, the rising period shown in Figure 4b; the switch connects the inverting input terminal of the operational amplifier to the second resistor Rb, and the integrating circuit discharges at a fixed rate according to the reference voltage Vref. The time count is Td, the falling period as shown in Figure 4b, so the voltage Vin of the vehicle LCD backlight source is obtained by the following formula (the negative sign "-" represents the current direction):

Vin=|−Vref((Ra/Rb)·(td/tu))|.

得到电流测量值。In a preferred embodiment of the present invention, as shown in FIG. 5 , the current detection unit includes a measurement resistor R and an ADC converter. The current of the vehicle LCD backlight source passes through the measurement resistor R, converts the current value into a voltage value, and uses the ADC converter to measure the voltage VR across the measurement resistor _R , through

Get the current measurement.

The monitoring unit obtains the use duration and brightness information of the vehicle-mounted liquid crystal display screen backlight, and obtains the vehicle-mounted liquid crystal display screen according to the voltage measurement value detected by the voltage detection unit and the current measurement value detected by the current detection unit. The actual power value of the backlight source; the corresponding calibration power value is determined in the data calibration table of the backlight source of the vehicle-mounted LCD display screen according to the obtained use time and brightness information of the vehicle-mounted LCD display screen backlight source, wherein the vehicle-mounted LCD display screen The data calibration table of the backlight source is used to calibrate the power calibration value that the vehicle-mounted LCD display backlight source with different use time should have when working with the corresponding brightness information; compare the actual power value and the calibrated power value of the vehicle-mounted LCD display backlight source, Determine whether the backlight source of the vehicle LCD screen is abnormal.

For the specific type of vehicle LCD screen to be tested, based on the aging degree of the vehicle LCD display screen, a data calibration table between the brightness information of the vehicle LCD display screen backlight and the power consumption is established and stored. The data calibration table of the backlight source of the vehicle-mounted liquid crystal display screen is a collection of normal operating condition parameter data of the backlight source of the vehicle-mounted liquid crystal display screen. The monitoring device for the vehicle-mounted liquid crystal display screen backlight according to the embodiment of the present invention further includes a storage unit (not shown in the figure), and the data calibration table of the vehicle-mounted liquid crystal display screen backlight is stored in the storage unit.

The data calibration table of the vehicle LCD backlight source includes a plurality of calibration parameter data, and each calibration parameter data may include rated voltage value, rated current value, use time, brightness information, calibration current value, calibration voltage value and calibration power value.

The rated voltage value and rated current value are the rated power supply voltage value and rated power supply current value of the specific type of vehicle LCD display backlight under test, such as 12V/100mA, 24V/200mA, the specific type of vehicle LCD display screen under test If the backlight source can work under the conditions of different rated supply voltage and rated supply current, the corresponding settings must be made in the calibration parameter data. If it only works under the condition of a single rated supply voltage and rated supply current If it is under, it is not necessary to set it in the calibration parameter data.

The use time is the actual working time of the backlight of the vehicle LCD screen, which can be timed by the timing unit, and the use time can be stored in the storage part in real time, or the use time can be updated in the storage part when the vehicle LCD screen is turned off. Of course, the monitoring device for the backlight of the vehicle-mounted liquid crystal display screen may also include a timing unit to time the working time of the backlight of the vehicle-mounted liquid crystal display screen, and store the use time in the monitoring device of the backlight of the vehicle-mounted liquid crystal display screen. in the storage unit.

The brightness information can be the luminous brightness level of the tested specific type of vehicle LCD backlight, for example, can be set as a percentage of 0-100, or can be a specific brightness value (lumens).

The calibrated current value and the calibrated voltage value are based on the voltage value and current value ( The voltage value is associated with the current value). Each piece of calibration parameter data records the voltage value and current value of the tested specific type of vehicle-mounted LCD display backlight when it emits light with corresponding brightness information, and the calibrated current value and calibrated voltage value can be a specific numerical fluctuation range, It can also be a specific numerical value.

The calibrated power value is determined according to the calibrated current value and the calibrated voltage value, and is adapted to the values of the calibrated current value and the calibrated voltage value, and the calibrated power value may be a numerical value or a numerical fluctuation range.

Therefore, each calibration parameter data records that under the condition that rated current and voltage are applied to the backlight source of a specific type of vehicle LCD screen with different use time, when the vehicle LCD screen emits light with corresponding brightness information, the calibration should have. The current value and the calibration voltage value, and the calibration power value obtained based on the calibration current value and the calibration voltage value.

When the vehicle-mounted liquid crystal display backlight source works, it emits light with a certain brightness. When the monitoring unit monitors the working condition of the vehicle-mounted LCD display backlight, the monitoring unit acquires the usage time of the vehicle-mounted LCD display backlight and the brightness information related to the current brightness, and detects the vehicle-mounted LCD display backlight. The current measurement value and voltage measurement value are obtained, and the actual power value of the vehicle LCD backlight source is obtained based on the detected current measurement value and voltage measurement value.

According to the monitoring request, the monitoring unit detects the current measurement value and the voltage measurement value of the backlight source of the vehicle LCD screen under a brightness condition (based on a brightness information) to obtain the actual power value; the monitoring unit can also be used under different brightness conditions. (Based on multiple brightness information), the current measurement value and voltage measurement value of the backlight source of the vehicle LCD screen are detected, and multiple actual power values are obtained. Obtaining the current measurement value and voltage measurement value of the vehicle-mounted LCD display backlight under multiple brightness conditions is conducive to comprehensively monitoring the working conditions of the vehicle-mounted LCD display backlight. Wherein, the monitoring unit can use PWM signal to adjust the brightness information output to the vehicle-mounted LCD display backlight, that is, adjust the brightness information of the vehicle-mounted LCD display backlight through the PWM signal, and maintain the voltage of the vehicle-mounted LCD display backlight. Or the current remains unchanged, adjust the duty cycle of the PWM signal, and the backlight of the vehicle LCD screen flashes on and off. When the flashing frequency of the backlight source of the vehicle LCD screen exceeds a certain value, the human vision can only realize the change of the screen brightness. Long on-time results in high brightness, while short on-time results in low brightness.

Preferably, the monitoring of the backlight source of the vehicle-mounted liquid crystal display screen is performed when the vehicle-mounted liquid crystal display screen backlight source reaches a preset use time, the monitoring unit sends preset brightness information to the vehicle-mounted liquid crystal display screen backlight source, and the vehicle-mounted liquid crystal display screen backlight source uses The preset brightness information emits light, and there is corresponding calibration parameter data in the data calibration table of the backlight source of the vehicle-mounted liquid crystal display screen. For example, as shown in Table 1, when the vehicle LCD backlight reaches 6200, 6400, 6600, 6800, 7000, 7200, 7400, and 7400 hours of use, the vehicle LCD backlight will operate at a preset brightness of 50%. It emits light and monitors the backlight of the vehicle LCD screen.

The monitoring unit determines the calibration in the calibration parameter data with the same or similar use duration and brightness information in the data calibration table of the vehicle-mounted LCD backlight according to the obtained use time and brightness information of the vehicle LCD backlight. Power value; compare the actual power value of the vehicle LCD backlight with the determined calibration power value, if the actual power value of the vehicle LCD backlight is within the range of the extracted calibration power value (that is, the vehicle LCD display If the actual power value of the screen backlight does not exceed the threshold range of the extracted calibration power value, or the actual power value of the vehicle LCD backlight is within the numerical fluctuation range of the extracted calibration power value), the vehicle LCD display The backlight source of the screen is working under normal working conditions, otherwise, the backlight source of the vehicle LCD screen is in an abnormal state, and a sound or text alarm is issued.

Therefore, the monitoring device for the backlight of the vehicle-mounted liquid crystal display according to the embodiment of the present invention can monitor the vehicle-mounted liquid crystal display by comparing the actual power value of the backlight of the vehicle-mounted liquid crystal display with the calibration power value in the corresponding calibration parameter data in the data calibration table. The normal working conditions of the LCD backlight can effectively avoid the LCD failure caused by the aging of the vehicle LCD backlight.

In addition, in order to timely discover the circuit fault of the backlight source of the vehicle-mounted liquid crystal display screen, in the monitoring device of the backlight source of the vehicle-mounted liquid crystal display screen according to the embodiment of the present invention, the monitoring unit compares the current measurement value and/or the current measurement value of the vehicle-mounted liquid crystal display screen backlight source and/or The voltage measurement value is compared with the calibration current value and the calibration voltage value corresponding to the calibration power value determined in the data calibration table to determine whether the backlight source of the vehicle LCD screen is abnormal.

The monitoring unit compares the current measurement value and/or the voltage measurement value of the vehicle-mounted LCD display backlight with the calibration current value and the calibration voltage value corresponding to the determined calibration power value, so as to monitor the operation of the vehicle-mounted LCD display backlight. situation.

If the current measurement value of the vehicle LCD backlight exceeds the range of the calibration current value (that is, the current measurement value of the vehicle LCD backlight exceeds the threshold range of the value of the calibration current value, or the vehicle LCD backlight If the current measured value of the vehicle is not within the numerical fluctuation range of the calibrated current value), the on-board LCD backlight is in an abnormal state, and a sound or text alarm is issued; or, if the voltage measured value of the on-board LCD backlight exceeds the calibrated voltage value range (that is, the voltage measurement value of the vehicle LCD backlight exceeds the threshold range of the value of the calibrated voltage value, or the voltage measurement value of the vehicle LCD backlight is not within the numerical fluctuation range of the calibrated voltage value), then When the LCD backlight is in an abnormal state, a sound or text alarm is issued.

Preferably, first compare the voltage measurement value of the vehicle LCD backlight with the voltage calibration value in the data calibration table, when the voltage measurement value of the vehicle LCD backlight is within the range of the calibration voltage value (that is, the vehicle When the voltage measurement value of the LCD backlight source does not exceed the threshold value range of the value of the calibration voltage value, or the voltage measurement value of the vehicle LCD display backlight source is within the numerical fluctuation range of the calibration voltage value), then the vehicle LCD display The current measurement of the backlight is compared to the current calibration value in the data calibration table.

The monitoring device for the backlight source of the vehicle-mounted liquid crystal display screen according to the embodiment of the present invention can monitor the current value and/or the voltage measurement value of the vehicle-mounted liquid crystal display screen backlight source by comparing it with the calibrated current value and the calibrated voltage value in the data calibration table. The normal working condition of the backlight of the vehicle LCD screen can effectively avoid the failure of the LCD screen caused by the circuit failure of the backlight source of the vehicle LCD screen.

The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the above method are implemented.

A computer device includes a memory, a processor and a computer program stored on the memory and executable on the processor, the processor implementing the steps of the above method when the program is executed.

Those skilled in the art will appreciate that logic and/or steps represented in flowcharts or otherwise described herein, for example, may be considered an ordered listing of executable instructions for implementing logical functions, may be embodied in in any computer-readable medium for use by an instruction execution system, apparatus, or device (such as a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device), or Used in conjunction with these instruction execution systems, apparatus or devices. For the purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport the program for use by or in connection with an instruction execution system, apparatus, or apparatus.

More specific examples (non-exhaustive list) of computer readable media include the following: electrical connections with one or more wiring (electronic devices), portable computer disk cartridges (magnetic devices), random access memory (RAM), Read Only Memory (ROM), Erasable Editable Read Only Memory (EPROM or Flash Memory), Fiber Optic Devices, and Portable Compact Disc Read Only Memory (CDROM). In addition, the computer readable medium may even be paper or other suitable medium on which the program may be printed, as the paper or other medium may be optically scanned, for example, followed by editing, interpretation, or other suitable medium as necessary process to obtain the program electronically and then store it in computer memory.

It should be understood that various parts of the present invention may be implemented in hardware, software, firmware or a combination thereof. In the above-described embodiments, various steps or methods may be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one or a combination of the following techniques known in the art: Discrete logic circuits, application specific integrated circuits with suitable combinational logic gates, Programmable Gate Arrays (PGA), Field Programmable Gate Arrays (FPGA), etc.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims (15)

1. a monitoring method of vehicle-mounted liquid crystal display backlight, is characterized in that, comprises the steps: Obtain the usage time, brightness information and actual power value of the backlight source of the vehicle LCD screen; The corresponding calibration power value is determined in the data calibration table of the vehicle-mounted LCD display backlight according to the obtained usage time and brightness information of the vehicle-mounted LCD display backlight, wherein the data calibration table of the vehicle-mounted LCD display backlight uses The power calibration value that should have when calibrating the vehicle-mounted LCD display backlight of different use time with the corresponding brightness information; Compare the actual power value and the calibration power value of the backlight source of the vehicle-mounted liquid crystal display screen to determine whether the backlight source of the vehicle-mounted liquid crystal display screen is abnormal. 2. the monitoring method of vehicle-mounted liquid crystal display screen backlight as claimed in claim 1 is characterized in that, according to the aging rate of vehicle-mounted liquid crystal display screen backlight, a plurality of data calibration tables of the vehicle-mounted liquid crystal display backlight are set, The calibration power values of multiple calibration parameter data in each data calibration table have a uniform numerical threshold or numerical fluctuation range. With the acceleration of the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, the numerical threshold or the numerical fluctuation range of the calibration power value of the multiple calibration parameter data in the corresponding data calibration table is increased. 3. the monitoring method of vehicle-mounted liquid crystal display backlight source as claimed in claim 1, is characterized in that, according to the aging rate of vehicle-mounted liquid crystal display screen backlight source, be provided with a data calibration table of described vehicle-mounted liquid crystal display screen backlight, With the acceleration of the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, the numerical threshold or the numerical fluctuation range of the calibration power value in the different calibration parameter data in the data calibration table is increased. 4. The monitoring method of the backlight source of the vehicle-mounted liquid crystal display screen as claimed in claim 1, wherein the monitoring method further comprises the steps before determining the corresponding calibration power value: establishing and storing a data calibration table for the vehicle LCD backlight source, and/or Monitoring the usage time of the vehicle-mounted LCD display backlight. 5. the monitoring method of the vehicle-mounted liquid crystal display backlight source as claimed in claim 1, is characterized in that, according to the use duration and brightness information of the vehicle-mounted liquid crystal display screen backlight source obtained, in the data calibration of the vehicle-mounted liquid crystal display screen backlight source Determine the calibration power value in the calibration parameter data with the same or similar usage duration and brightness information in the table. 6. The monitoring method of the vehicle-mounted liquid crystal display backlight as claimed in claim 5, wherein the vehicle-mounted liquid crystal display backlight is controlled to emit light with preset brightness information, and the working time of the vehicle-mounted liquid crystal display backlight is obtained in real time, Determine the calibration power value in the calibration parameter data with the same or similar usage time and brightness information in the data calibration table of the vehicle LCD backlight; or, When the preset use time of the vehicle-mounted liquid crystal display backlight source is reached, the vehicle-mounted liquid crystal display screen backlight source is monitored, so that the vehicle-mounted liquid crystal display screen backlight source emits light with preset brightness information. 7. The monitoring method of the vehicle-mounted liquid crystal display backlight source as described in one of claims 1-6, is characterized in that, comparing the actual power value and the demarcated power value of the vehicle-mounted liquid crystal display screen backlight source, if the vehicle-mounted liquid crystal display screen If the actual power value of the backlight source is within the range of the calibrated power value, then compare the current measurement value and/or voltage measurement value of the backlight source of the vehicle LCD screen with the calibration current value corresponding to the calibration power value determined in the data calibration table, The calibration voltage value is compared to determine whether the backlight source of the vehicle-mounted liquid crystal display screen is abnormal. 8. the monitoring method of vehicle-mounted liquid crystal display screen backlight as claimed in claim 7, is characterized in that, at first the voltage measurement value of vehicle-mounted liquid crystal display screen backlight and the calibration voltage corresponding to the calibration power value determined in the data calibration table When the voltage measurement value of the vehicle LCD backlight source is within the range of the calibration voltage value, then the current measurement value of the vehicle LCD display backlight source and the calibration power value determined in the data calibration table correspond. The calibration current value is compared. 9. A monitoring device for a vehicle-mounted liquid crystal display backlight, comprising a voltage detection unit, a current detection unit and a monitoring unit, the voltage detection unit and the current detection unit being respectively connected with the monitoring unit, The voltage detection unit detects the voltage measurement value of the vehicle-mounted liquid crystal display screen backlight, and the current detection unit detects the current measurement value of the vehicle-mounted liquid crystal display screen backlight; The monitoring unit obtains the use time and brightness information of the vehicle-mounted liquid crystal display backlight, and obtains the actual power value of the vehicle-mounted liquid crystal display backlight according to the voltage measurement value and the current measurement value; The use time and brightness information of the backlight source of the display screen determine the corresponding calibration power value in the data calibration table of the backlight source of the vehicle LCD screen, wherein the data calibration table of the backlight source of the vehicle LCD display screen is used to calibrate the vehicle-mounted LCD display screen backlight source with different durations. The power calibration value that the LCD backlight should have when working with the corresponding brightness information; compare the actual power value and the calibration power value of the vehicle LCD backlight to determine whether the vehicle LCD backlight is abnormal. 10. The monitoring device for the backlight of the vehicle-mounted liquid crystal display screen as claimed in claim 9, wherein the monitoring device for the backlight of the vehicle-mounted liquid crystal display screen further comprises a storage unit and a timing unit, The storage unit stores the data calibration table of the backlight of the vehicle-mounted liquid crystal display screen, The timing unit counts the usage time of the backlight source of the vehicle-mounted liquid crystal display screen, and stores the usage time data in the storage unit. 11. The monitoring device of the vehicle-mounted liquid crystal display backlight as claimed in claim 9, wherein, according to the aging rate of the vehicle-mounted liquid crystal display backlight, a plurality of data calibration tables of the vehicle-mounted liquid crystal display backlight are set, The calibration power values of multiple calibration parameter data in each data calibration table have a uniform numerical threshold or numerical fluctuation range. With the acceleration of the aging rate of the backlight source of the vehicle-mounted liquid crystal display screen, the numerical threshold or the numerical fluctuation range of the calibration power value of the multiple calibration parameter data in the corresponding data calibration table is increased. 12. The monitoring device of the vehicle-mounted liquid crystal display backlight as claimed in claim 9, wherein the monitoring unit controls the vehicle-mounted liquid crystal display backlight to emit light with preset brightness information, and obtains the vehicle-mounted liquid crystal display backlight in real time. the working time, determine the calibration power value in the calibration parameter data with the same or similar usage duration and brightness information in the data calibration table of the vehicle LCD backlight; or, When the preset usage time of the vehicle-mounted LCD display backlight is reached, the monitoring unit monitors the vehicle-mounted LCD display backlight, so that the vehicle-mounted LCD display backlight emits light with preset brightness information. 13. The monitoring device of the vehicle-mounted liquid crystal display backlight as claimed in claim 9, wherein the monitoring unit compares the actual power value and the demarcated power value of the vehicle-mounted liquid crystal display backlight, if the vehicle-mounted liquid crystal display If the actual power value of the screen backlight is within the range of the calibration power value, the monitoring unit will compare the current measurement value and/or voltage measurement value of the vehicle LCD backlight source with the calibration power value determined in the data calibration table. The corresponding calibration current value and calibration voltage value are compared to determine whether the backlight source of the vehicle-mounted liquid crystal display screen is abnormal. 14. The monitoring device of the vehicle-mounted liquid crystal display screen backlight as claimed in claim 13, wherein the monitoring unit first compares the voltage measurement value of the vehicle-mounted liquid crystal display screen backlight and the calibration power determined in the data calibration table When the voltage measurement value of the vehicle-mounted LCD display backlight is within the range of the calibration voltage value, the monitoring unit will then calibrate the current measurement value of the vehicle-mounted LCD display backlight with the data. Compare the calibration current value corresponding to the calibration power value determined in the table. 15. The monitoring device of the vehicle-mounted liquid crystal display backlight as claimed in claim 9, wherein the voltage detection unit comprises an operational amplifier, a capacitor, a switch, a first resistor Ra and a second resistor Rb, and the The input terminal of the same direction is grounded, the reverse input terminal can be connected to the first end of the first resistor Ra and the first end of the second resistor Rb respectively through the switch, and the second end of the first resistor Ra is connected to the vehicle LCD backlight source The second end of the second resistor Vb is connected to the reference voltage Vref, and the capacitor is connected between the inverting input end of the operational amplifier and the output end Vout, When the voltage detection unit detects the voltage of the vehicle-mounted liquid crystal display backlight, the switch connects the reverse input end of the operational amplifier to the first resistor Ra, and the voltage Vin of the vehicle-mounted liquid crystal display backlight is used to charge the integrating circuit, charging The time is Tu; then, the switch connects the inverting input terminal of the operational amplifier to the second resistor Rb, the integrating circuit discharges with the reference voltage Vref, and the discharge time is Td, then the voltage Vin of the vehicle LCD backlight is: Vin=|−Vref((Ra/Rb)·(td/tu))|.

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