1. Automobile lamps and lanterns
Automotive luminaires can be divided into two main categories, exterior lighting devices (lights) and signaling devices (signal lights). The function of the light is to illuminate the road ahead of the car in a dark environment. Lighting mainly refers to headlights, front fog lights, and reversing lightsOptical signaling devices include automotive signal lights and retroreflectors. Signal lights include turn indicators, brake lights, rear fog lights, and position lights. The function of a signal light is to indicate to other road users that the vehicle is about to turn in a certain direction or is braking or decelerating, so as to attract special attention to them.
Automobile lights are generally composed of three parts: insulated (fixed) brackets, LED tubes, and control circuits. The number of LED tubes is generally dozens, and they are evenly distributed into several electrical branches, and the LED tubes in each electrical branch are connected in series with each other, and the electrical branches are connected in parallel.
The control line generally provides 2 3 ports, each port accepts different levels of control voltage, and supplies power to the LED tube of the series-parallel structure after connecting the resistors of different resistance values in series, so that the lights have different brightness, and then realize different lamp logic functions, such as"Lighting"."Brakes"."Lighting Intensification".Wait.
In order to perform their proper function on the road, these luminaires installed on the vehicle must meet the following two characteristic requirements at the same time:
1) The light distribution requirements of the monomer lamp itself (i.e., light distribution performance).
In order for each luminaire to fulfill its specific function, its spatial light distribution must meet specific light distribution requirements.
At present, in the current national standards, there are strict and clear requirements and test methods for the light distribution performance requirements of each functional lamp, such as headlights, brake lights, turn signals, position lights, etc. When it comes to vehicle driving safety, these contents are the technical requirements of the national mandatory standards.
2) The installation position and layout requirements of the lamps on the vehicle.
Outside the vehicle, there are strict installation requirements for the type, number, location, chromaticity and overall layout of the installed lamps, in order to meet the geometric visibility of the lamps on the vehicle.
The relative position and number of lights for each function on the vehicle are strictly regulated in GB4785, so that the driving signals and vehicle contours of the vehicle when driving at night can be accurately accepted and recognized by other road users.
2. Lamp detection system
Inspecting the quality of finished lamps is the last step in the lamp production process, which is of great significance to ensure the pass rate of factory products. Due to the large number of LED tubes, it is very difficult to manually inspect, although at present, some manufacturers have designed equipment based on the illuminance test technology of the car lamp, or based on the image processing technology to check the quality of the car lamp, but the test procedures are cumbersome, so it is not suitable for the mass production of the car lamp.
As the main component that affects the safety of the vehicle, the management of the product is the implementation of national compulsory certification (CCC) and announcement management. CCC certification is that the motor vehicle lighting manufacturers directly apply for certification to the relevant departments, and the announcement management is that the vehicle enterprises report the motor vehicle lighting products to the management department as part of the vehicle announcement test content.
The two forms are different, but the assessment items, testing methods and requirements of lamp products are the same, and they are all tested with a separate lamp as a test sample, and must meet the requirements of light distribution performance.
The light distribution performance test of motor vehicle lamps and lanterns is to assess whether the external lighting and light signal devices (hereinafter referred to as lamps) installed on motor vehicles meet the requirements of lighting and light signal transmission capabilities that vehicles should have in road driving. According to the actual loading position of the special test bracket, the main function is to simulate the installation position on the actual vehicle in the lamp monomer test, its dimensional accuracy, the connection position is directly related to the effectiveness of the motor vehicle lamp light distribution performance test and the accuracy of the measurement results.
At present, the principle of the international light distribution performance test is to convert the direction and intensity requirements of light propagation of the lamp on the actual road into the requirements of the fixed screen in the laboratory. Usually the test screen of the lighting lamp is 25m away from the center of the lamp, and the test screen of the signal light is generally 316m。The single lamp uses the test bracket to simulate the loading position of the real car, is installed on the light distribution test platform, and measures the luminous intensity one by one on the series of position points or areas required by the standard through the three-axis rotation test platform.
During the test, the only basis for ensuring that the single lamp simulates the installation position of the real vehicle is the test bracket provided by the manufacturer, and the accuracy of the bracket is directly related to the effectiveness of the light distribution performance.
3. Quality testing system for finished products of automobile lights
The principle adopted by the designed lamp quality test system is: under the DC power supply voltage, the LED tube can be equivalent to 1 resistive load, so that the quality meets the requirements of the LED tube, and its equivalent resistance value should be stable within a range under the given power supply voltage, then if all the lamps in the electrical branch of the parallel structure meet the quality requirements, the power supply current will be stable in a certain range after a certain voltage is applied to the port of the control line;On the contrary, as long as 1 LED lamp does not meet the quality requirements, the value of the power supply current will be out of range, so that whether there is an LED tube in the lamp that does not meet the quality requirements by judging whether the power supply current is within a given range.