LED backlight: creating new life in the cracks

In the increasingly developed and mature liquid crystal display industry chain, the labor-intensive characteristics and relatively low entry threshold of the LED backlight industry have LED to an extremely fierce competition in the backlight industry. On the one hand, upstream key materials such as optical films are still in the hands of a few manufacturers, the price of materials is difficult to fall, and the cost of products remains high; On the other hand, it is also facing the pressure of downstream customers to continuously demand price cuts. Under the huge pressure at both ends of the industrial chain, the profit margin of backlight module products is getting smaller and smaller, and the operation and survival of some manufacturers, especially second-tier manufacturers, are becoming more and more difficult. How to improve product competitiveness through technological innovation has become a life-and-death issue for LED backlight enterprises. With the sharp drop in LED prices, the driving force to reduce costs by reducing the number of LEDs is weakening. In the next few years, the application of LED backlight in mobile terminals, televisions and other markets will continue to grow. Hou Yan, general manager of display lighting division of BOE Optoelectronic Technology Co. , Ltd. , told the reporter that at present, it seems that in the notebook computer market, almost all the traditional CCFL backlights are replaced by LED backlights; In the large-size desktop display and TV market, LED backlights are expected to replace CCFL backlights this year. As early as 2005, Sony and Sharp introduced RGB type direct led LCD TVs, but they were not accepted by consumers due to their high cost. In 2008, Samsung developed a side-light LCD TV based on white LED, which greatly reduced the cost and achieved success, and began the development trend of LCD TV. In 2012, the TV lens developed by Enplas greatly reduced the LED usage of direct backlight, and the cost was lower than that of side light backlight, thus the direct LCD TV was reborn. Pei Xiaoming, vice president of Shenzhen Ruifeng Optoelectronics Co. , Ltd. , told reporters that the LED in the side light backlight module is located on the side of the backlight module, and light is emitted from the surface of the liquid crystal display through the light guide plate, the LED in the direct backlight module is located at the bottom of the backlight module, and the luminous angle of the LED is enlarged through the secondary lens, thus reducing the amount of LED. 'It should be said that these two methods have their own advantages and disadvantages. 'Li Xiufu, vice president of the Research Institute of Suzhou Dongshan Precision Manufacturing Co. , Ltd. and director of the backlight Research Institute, said in an interview with reporters,' the side-light modular machine has good compatibility, high reliability and good strength, support Large size; The side light all-in-one machine is easier to realize ultra-thin and narrow frame design, while the direct all-in-one machine is simpler to assemble and has a price advantage. 'So what direction are the mainstream companies of these two technology routes working in? Pei Xiaoming said that with the change of the light input mode of the side light backlight module, it puts forward higher requirements on the brightness, power and heat dissipation capability of the LED, side Light LED packaging tends to be more standardized, the power of packaging products of the same size is increasing, and the material performance and structural performance of LED bracket are continuously improving. While the direct backlight technology is moving towards low light mixing and low cost, the LED power is continuously increased from 1W to 3 W, and the bracket material is also developed from PCT to EMC, the luminous body is close to the electric light source, the diameter of the luminous surface is continuously reduced, and the heat dissipation capability of the LED is also improved by the chip from formal installation to inverted cladding. 'The backlight design of TV usually needs to weigh the cost, thickness and brightness, and various technical routes also have their own advantages and disadvantages. 'Hou Yan said,' but in terms of the way of light input, it is certain that with the sharp drop in LED prices, the driving force to reduce costs by reducing the number of LEDs used is weakening. 'In response to OLED and LED display challenges, technological innovation has driven continuous cost reduction, thus winning market space with high cost performance. Although they still have many defects, the emergence of self-illuminating OLED and LED displays has brought great impact to the LED backlight module industry. Moreover, it is not only the advantage of self-illumination, but also the advantages of high color gamut, high contrast, wide viewing angle, flexibility of OLED screen and large size of LED screen, which make LED backlight module enterprises treading on thin ice. How to deal with the challenges brought by OLED and LED displays? Mainstream companies have consistently identified the indicator of color gamut. Color gamut, or color saturation, refers to the ability of the display to restore natural colors. The higher the color gamut, the brighter the displayed image and the closer it is to the natural real color. Generally, the color gamut of liquid crystal display is about 72, while the color gamut of OLED can reach more than 100. How to improve the color gamut of LED backlight liquid crystal display? Yan Xiaoming said that the first is to use a new narrow half-wave wide red and green powder combination with a color gamut of about 85; The second is to add green chip compensation, the color gamut can reach more than 95; Third, the quantum dot phosphor scheme can achieve more than 100 color gamut. There are ways, but they all have their own limitations. Qiao Mingsheng, technical director of Qingdao Hisense Electric Co. , Ltd. , said in an interview that the implementation of this scheme is relatively simple and the cost is relatively low, but the achievable color gamut value is also low; The second two-color chip solution can achieve a relatively high color gamut value, but the driving is complex and the life of the two chips is inconsistent; The third quantum dot technology scheme can achieve a high color gamut value, but it also has high requirements for material packaging and cannot meet the requirements of environmental protection for the time being. 'Improving color gamut is only one of our efforts. Ultra-thin body, ultra-narrow frame, high brightness, ultra-low power consumption, curved surface and so on are all countermeasures for LED backlight liquid crystal display technology to meet the challenges of new technologies. The final goal is to promote continuous cost reduction through technological innovation and win market space with high cost performance. Many experts have reached a consensus on the development direction of backlight technology.