The factors that affect the lifespan of LED display screens include internal and external factors, including the performance of peripheral components, the performance of LED light-emitting devices, and the fatigue resistance of products; The working environment with LED display screens and other internal factors.
1. Impact of peripheral components
In addition to LED light-emitting devices, LED display screens also use many other peripheral components, including circuit boards, plastic shells, switch power supplies, connectors, chassis, etc. Any component failure may lead to a decrease in the lifespan of the display screen. So, the longest lifespan of a display screen is determined by the lifespan of the key component with the shortest lifespan. For example, LED, switch power supply, and metal casing are all selected according to the 8-year standard, while the protective process performance of the circuit board can only support its operation for 3 years. After 3 years, damage may occur due to corrosion, so we can only obtain a 3-year lifespan display screen.
2. The Influence of LED Light Emitting Device Performance
LED light emitting devices are the most critical and lifespan related components of display screens. For LEDs, the main indicators are attenuation characteristics, waterproof vapor permeability characteristics, and UV resistance. If LED display screen manufacturers fail to evaluate the performance indicators of LED devices and apply them to display screens, it will lead to a large number of quality accidents and seriously affect the lifespan of LED display screens.
3. The impact of product fatigue resistance
The fatigue resistance of LED display screen products depends on the production process. The fatigue resistance of the module produced by the poor three prevention treatment process is difficult to guarantee. When the temperature and humidity change, cracks will appear on the protective surface of the circuit board, leading to a decrease in protective performance.
So the production process of LED display screens is also a key factor in determining the lifespan of display screens. The production processes involved in the production of display screens include: component storage and pre-treatment process, furnace welding process, three prevention treatment process, waterproof sealing process, etc. The effectiveness of the process is related to material selection and ratio, parameter control, and operator quality. For the vast majority of LED display screen manufacturers, experience accumulation is crucial. A factory with years of experience will be more effective in controlling the production process.
4. Impact of Work Environment
Due to different uses, the working conditions of the display screen vary greatly. From an environmental perspective, the indoor temperature difference is small, without the influence of rain, snow, and ultraviolet radiation; The maximum temperature difference outdoors can reach 70 degrees, plus wind, sun, and rain. The harsh environment can exacerbate the aging of the display screen, and the working environment is an important factor affecting the lifespan of the display screen.
The lifespan of LED displays is determined by various factors, but the end of lifespan caused by many factors can be continuously extended through the replacement of components (such as switching power supplies). LED, on the other hand, cannot be replaced in large quantities. Therefore, once the LED lifespan ends, it means the end of the display screen lifespan. In a certain sense, the lifespan of LEDs determines the lifespan of display screens. The lifespan of LEDs is usually determined by the time the luminous intensity decays to 50% of its initial value. LED, as a semiconductor material, is often said to have a lifespan of 100000 hours, but that is an evaluation under ideal conditions. However, it cannot be achieved under actual usage conditions. We have a simple experimental method and calculation formula to calculate the lifespan of an LED: place the LED under the same conditions as the actual working environment for 1000 hours, measure the initial and final values of light intensity, and then calculate the lifespan of the LED through the formula. We selected a famous brand of blue tube and measured a final value of 0.88 after working for 1000 hours in an environment with an ambient temperature of 50 ℃ and a current of 20mA × Based on the initial value, we can calculate that the lifespan of the blue tube in this environment is 5422 hours according to the formula.
We say that LED lifespan determines the lifespan of a display screen, but we do not mean that LED lifespan is equal to the lifespan of the display screen. Due to the fact that not every LED is working at full load at all times when the display screen is working, the lifespan of the display screen should be 6-10 times that of the LED when playing video programs normally. When the LED is working at low current, its lifespan can be longer. Therefore, the lifespan of the display screen using this brand of LED can reach around 50000 hours.
How to prolong the lifespan of LED? In general, we can start from two aspects: device manufacturing and device application. In terms of device manufacturing, choose high-quality epitaxial materials; Increase chip area and reduce current density; Balanced current density; Reduce thermal resistance; Choosing packaging materials with excellent performance and strong UV resistance can prolong the lifespan of LEDs.
From the perspective of device applications, consider heat dissipation as a central task from module design to engineering implementation and even future system maintenance; Reduce the working current of LED; Properly configuring LEDs to achieve synchronous attenuation of various primary colors can extend the lifespan of LEDs.
Some manufacturers do not pay attention and replace the LED specific backlight ink with ordinary white text ink, which is equivalent to adding a layer of hard paint to seal the heat. After multiple failures, some manufacturers have accepted new concepts and processes, focusing on overall cooling solutions. The aluminum substrate is coated with LED specific heat dissipation white backlight ink. If a light yellow backlight ink is specified, it will enhance the reflectivity to 91%. Spraying soft ceramic heat dissipation paint between copper foil substrate and aluminum substrate can reduce the use of Japanese thermal conductive adhesive film and improve breakdown voltage resistance at an extremely low cost.
The stability and quality of LED lights are crucial to the heat dissipation of the light body itself. Currently, natural heat dissipation is commonly used for the heat dissipation of high brightness LED full color displays in the market, but the effect is not ideal. Poor heat dissipation can also affect the lifespan of the lamp itself.
The cost-effective and effective way to protect LED display screens or lighting fixtures from climate erosion and effectively transmit heat is to spray soft ceramic heat dissipation paint. Only starting from the overall concept of heat dissipation and reducing thermal resistance interference is the key to the acceptance of large LED lamps. The protective casing of lighting fixtures should abandon traditional electroplating or baking paint. These two construction methods will seal the heat back inside the fixture. Outdoor LED display screens will be exposed to natural environments for a long time. When outdoor temperatures are high, the heat dissipation of LED display screens becomes an important issue. The heat dissipation of LED display screens indirectly affects the service life of LED display screens, and even more importantly, directly affects the normal use and safety of LED display screens.