Eight technical control LED display quality assurance
1, anti-static LED display assembly plant should have a good anti-static measures.
Special anti-static, anti-static floor, antistatic soldering pen, static radio pad, anti-static, anti-static clothing, humidity control, equipment grounding (
Especially cut foot machine)
Are the basic requirements, and to use the static all tested periodically.
2, mixed lights the same colors in different brightness of LED to mixed light, or in accordance with the law of discrete design of plug light figure to plug the lamp, to ensure the consistency of the whole screen brightness of each color.
This procedure if there is a problem, there will be a display local luminance inconsistent phenomenon, directly affect the display of LED display.
3, LED display module drive circuit design of driver circuit board driver IC configuration will affect the brightness of the leds.
Due to the driver IC output current on the PCB board transmission distance too far, will make the transmission path of pressure drop is too large, affect the normal work voltage results in the decrease of the brightness of LED.
We often find the LED brightness around the LED display module is lower than among some, it is for this reason.
So to ensure the consistent sexual display brightness, distribution of its driving circuit is designed.
4, virtual welding control LED display when the LED is not bright, often more than 50% probability for the various types of virtual welding, such as LED tube feet virtual welding, IC pin virtual welding, welding and row needle row, etc.
The improvement of these issues need to improve process strictly and strengthen the quality inspection to solve.
The vibration test before delivery also can yet be regarded as a kind of good test method.
5, wave soldering temperature and time are required to strictly control the wave crest welding temperature and furnace time, recommended for: preheat temperature 100 ℃ + / - 5 ℃, the highest do not exceed 120 ℃, and the requirement of preheating temperature increasing is smooth, the welding temperature is 245 ℃ + 5 ℃, welding time suggest no more than 3 seconds, after furnace vibration or shock LED of avoid by all means, until the normal temperature state.
Crest welder regularly test the temperature of the parameters, this is determined by the characteristics of LED, too hot or fluctuations in temperature can directly damage the LED or LED quality hidden trouble, especially for small size, such as 3 mm, round and oval LED.
6, heat dissipation design LED work when heating, the temperature is too high will affect the LED attenuation speed and stability, so the heat dissipation of PCB design, the enclosure ventilation cooling design will affect the performance of the LED.
7, design result LED the nominal current of the 20 ma, general advice its maximum current for no more than 80% of the nominal value, especially for display point spacing is small, due to the poor heat dissipation condition, should also reduce the current value.
According to experience, due to attenuation of red, green and blue leds inconsistencies, targeted to reduce the current value of blue and green leds, to keep the screen after long time use the consistency of the white balance.
8, the verticality control lamp for upright type LED, there should be enough when a furnace technology to ensure the LED is perpendicular to the PCB.
Any deviation will affect the already set a good LED brightness uniformity and brightness of color piece.