In addition to raw materials how to identify LED display SMD packaging technology is not content?
LED devices accounted for about 40% to 70% of the cost of LED display, LED display cost greatly reduced due to the cost of LED devices to reduce. LED package quality is good or bad impact on the quality of LED display. The key to packaging reliability includes the choice of chip material, the choice of packaging materials and process control. In addition, strict reliability standards are the key to testing high-quality LED devices.
With the LED display gradually toward the high-end market penetration, the LED display device quality requirements are getting higher and higher. This article on the high-quality LED display device package practical experience, to explore high-quality LED display device key technology.
LED display device package status quo
SMD (Surface Mounted Devices) refers to the surface mount type package structure LED, mainly PCB structure of the LED (ChipLED) and PLCC structure of the LED (TOP LED). This article mainly studies TOP LED, the following mentioned in the SMD LED refers to the TOP LED.
The main material components used in the LED display device package include the bracket, chip, solid crystal, bond and package. Here from the packaging materials to introduce some of the current domestic basic development status.
1.1 LED bracket
(1) the role of the stent. PLCC (Plastic Leaded Chip Carrier) bracket is the carrier of SMD LED device, the LED reliability, light and other performance play a key role.
(2) the production process of the stent. PLCC stent production process, including metal strip with punching, electroplating, PPA (polyphthalamide) injection molding, bending, five-dimensional three-dimensional inkjet and other processes. Among them, electroplating, metal substrates, plastic materials occupy the main cost of the stent.
(3) the structure of the bracket to improve the design. PLCC brackets due to the physical combination of PPA and metal bonding, the gap will become larger after the high temperature reflow furnace, resulting in water vapor easily along the metal channel into the device inside and thus affect the reliability.
In order to improve product reliability to meet the high-end market demand for high-quality LED display devices, part of the package to improve the structure of the stent design, such as Foshan City Star Electronics Co., Ltd. using advanced waterproof structure design, bending stretch Method to extend the water vapor into the path of the stent, while the inside of the stent to increase the trough, waterproof step, water hole and other multiple waterproof measures, as shown in Figure 1. The design not only saves the cost of packaging, but also improve product reliability, has been widely used in outdoor LED display products. Through the SAM (Scanning Acoustic Microscope) test bending structure design of the LED bracket package and the normal bracket airtight, the results can be found using the bending structure design of the product better air tightness.
