Backlight outlook

In the liquid crystal display industry chain, the labor-intensive characteristics of the LED backlight industry and the relatively low entry barrier have led to the current 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, material prices are difficult to fall, product costs remain high; on the other hand, there is also pressure from downstream customers to continuously demand price reduction. Under the tremendous pressure on both ends of the industry 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 getting more and more difficult. How to enhance product competitiveness through technological innovation has become a matter of life and death for LED backlight companies.

Sidelight and straight down have their own

As the price of LEDs has fallen sharply, the driving force to reduce costs by reducing the number of LEDs is waning.

Straight down LED strip

As early as 2005, Sony and Sharp introduced the RGB-type direct-lit LED LCD TV, but it was not accepted by consumers because of its high cost. In 2008, Samsung developed a side-lit LCD TV based on white LEDs, which was greatly reduced in cost and achieved success, and began to lead the development trend of LCD TVs. In 2012, the TV lens developed by Enplas made the LED usage of the direct-lit backlight greatly reduced, the cost was lower than that of the edge-lit backlight, and the direct-lit LCD TV was reborn. Yan Xiaoming, vice president of Shenzhen Ruifeng Optoelectronics Co., Ltd., told the China Electronics News that the LEDs in the edge-lit backlight module are located on the side of the backlight module, and the light is emitted from the surface of the liquid crystal display through the light guide plate. In the backlight module, the LED is located at the bottom of the backlight module, and the secondary lens is used to enlarge the illumination angle of the LED, thereby reducing the amount of LED.

"It should be said that these two methods have their own advantages and disadvantages." Li Xiufu, deputy dean of the research institute of Suzhou Dongshan Precision Manufacturing Co., Ltd. and director of the Institute of Backlighting, said in an interview with the reporter of China Electronics News, "Side-light module The machine has good compatibility and high reliability. The direct-type modular machine has good strength and supports large size. The side-light integrated machine is easier to realize ultra-thin and narrow frame design, and the straight-down one-piece machine assembly is simpler and has a price advantage."

Then, what are the mainstream companies of these two technology routes working in? In this direction, Xiao Ming said that with the change of the light-input mode of the edge-lit backlight module, it has proposed more brightness, power and heat dissipation capability of the LED. The high requirements, the edge-lit LED package tends to be more standardized, the power of the same-sized package products is increasing, and the material performance and structural performance of the LED bracket are constantly increasing.

"The backlight design of TV usually needs to be trade-off between cost, thickness and brightness, and various technical routes have their own advantages and disadvantages." Hou Yan said, "but specifically to the way of entering the light, it is certain that with The sharp drop in LED prices is driving down the drive to reduce costs by reducing the number of LEDs used."

Addressing OLED and LED display challenges

Through technological innovation, the cost is continuously reduced, so that the market space is won at a high cost performance.

Although there are still many defects in each, the emergence of self-illuminating OLEDs and LED displays has brought a big impact to the LED backlight module industry. Moreover, it is not only the advantage of self-illumination, high color gamut, high contrast, wide viewing angle, flexibility of OLED screen, and large size of LED screen, which make LED backlight module enterprises like thin ice.

How to deal with the challenges brought by OLED and LED display? The mainstream enterprises have consistently checked the gamut. The color gamut, ie the color saturation, refers to the ability of the display to restore natural colors. The higher the color gamut, the more vivid the image is, the closer it is to the natural color. Generally, the color gamut of a liquid crystal display is about 72%, and the color gamut of an OLED can reach more than 100%.

So how to improve the color gamut of the LED backlight LCD screen? Yan Xiaoming said, first, with a new narrow half-wave width red and green powder combination, the color gamut is about 85%; the second is to add green chip compensation, the color gamut can reach More than 95%; the third is to use the quantum dot phosphor solution, you can achieve more than 100% color gamut.

The method is there, but each has its own limitations. Qiao Mingsheng, technical director of Qingdao Hisense Electric Co., Ltd., said in an interview with China Electronics News that the first scheme is simpler to implement and the cost is relatively low, but the achievable gamut value is also lower; The two-color chip solution can achieve higher color gamut values, but the driving is complicated and the life of the two chips is inconsistent. The third quantum dot technology solution can achieve high color gamut values, but the requirements for material packaging are also high. Unable to meet environmental requirements.

"Improving color gamut is only one of our efforts. Ultra-thin body, ultra-narrow bezel, high brightness, ultra-low power consumption, curved surface, etc. are the countermeasures for LED backlight LCD technology to meet the challenges of new technologies. The ultimate goal is still Through technological innovation, the cost is continuously reduced, and the market space is won with high cost performance.” Many experts reached a consensus on the development direction of backlight technology.

Related Links

The LED backlight module is one of the key components of the LCD panel. Its importance is mainly reflected in three aspects: First, the backlight module basically determines the power consumption of the TV. Since the TFT-LCD panel changes the alignment direction of liquid crystal molecules by an electric field, its power consumption is extremely low. The power consumption of TFT-LCD is mainly composed of TFT circuit, driving circuit and backlight module. The power consumption of the backlight module accounts for 80% of the power consumption of the TFT-LCD, while the power consumption of the TFT-LCD panel accounts for 80% of the LCD TV. Therefore, it can be seen that the overall performance of the backlight module in the LCD TV The highest share of consumption.

Second, the backlight module basically determines the cost of the TFT-LCD panel. The backlight module consists of three parts: LED light source, light guide plate and optical film, accounting for 72% of the cost of the entire backlight module. The light source is the light tube. The function of the light guide plate is to atomize the line light source into a surface light source. The main function of the optical film is to condense light and improve brightness. Among them, the optical film is the most expensive, accounting for 44% of the cost of the backlight module, the light guide plate accounts for 16%, the lamp tube accounts for 12%, and other lamps such as the lampshade account for 28%. More than 70% of the cost of the panel module is raw materials, and the backlight module accounts for 20% to 30% of the cost of the panel module. Therefore, the backlight module accounts for the highest share of the cost of the TFT-LCD.

Third, the advantages and disadvantages of the backlight module basically determine the user's experience of the terminal display effect. The demand for display effects has gradually increased, and the demand for wide viewing angle, low power consumption, faster response speed, and richer color expression has become a key factor in determining the quality of backlight modules.

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