Mini LED backlight chip makes its debut

1. Mini LED backlight development background

As my country enters the normalization stage of epidemic prevention and control, the recovery trend of consumption is gradually consolidated. Looking back on 2020, the "stay-at-home economy" is undoubtedly the biggest hot spot in the consumer field, and the booming development of the "stay-at-home economy" has also contributed to the overall growth of new display technologies such as 8K, quantum dots, and Mini LED. Therefore, with the strong promotion of leading companies such as Samsung, LG, Apple, TCL, and BOE, ultra-high-definition Mini TVs using direct Mini LED backlights have become an industry hot spot. In 2023, the market value of TV backplanes using Mini LED backlights is expected to reach US$8.2 billion, of which 20% of the cost is in Mini LED chips.

Direct-type backlight Mini LED has the advantages of high resolution, long life, high luminous efficiency, and high reliability. At the same time, Mini LED can achieve high-contrast HDR with local dimming zoning control; with high color gamut quantum dots, it can achieve a wide color gamut >110% NTSC. Therefore, Mini LED technology has attracted much attention and has become an inevitable trend in technology and market development.

2. Mini LED backlight chip parameters

Nationstar Semiconductor, a wholly-owned subsidiary of Nationstar Optoelectronics, has actively developed Mini LED epitaxy and chip technology for Mini LED backlight applications. We have carried out key technical research on product reliability, anti-static ability, welding stability, light color consistency and other aspects, and have formed two series of Mini LED backlight chip products, including 1021 and 0620. At the same time, in order to better adapt to the requirements of Mini COG packaging, Nationstar Semiconductor has developed a new high-voltage 0620 product to provide customers with more options.

3. Features of Mini LED backlight chips

1. Highly consistent epitaxial structure design, strong chip anti-static ability

In order to improve the wavelength concentration of Mini LED backlight chips, Nationstar Semiconductor uses unique epitaxial layer stress control technology to reduce internal stress and ensure consistency during the quantum well growth process. In terms of chips, ultra-high anti-static capabilities are achieved through a customized high-reliability DBR flip-chip solution. According to the test results of a third-party laboratory, the anti-static capability of Nationstar Mini LED backlight chips can exceed 8000V, and the anti-static performance of the product reaches the forefront of the industry.

2. Low OD wide-angle light emission chip structure to achieve ultra-thin backlight applications

In order to meet the ultra-clear and ultra-thin requirements of Mini LED backlight, Nationstar Semiconductor Mini LED backlight chip innovatively adopts a low OD large light emission angle chip structure, which increases the light emission angle of the chip by 20-30°, so that the Mini backlight module can achieve a uniform light mixing effect even at low OD, thus reducing the thickness of the entire machine and achieving ultra-thinness.

3. Solder-free process, improved packaging stability

Due to the small size of the Mini chip, it is impossible to accurately control the amount of solder paste, whether using traditional dot solder paste or brushing solder paste solutions. This can easily lead to chip welding problems such as drift, misalignment, large porosity, and failure. This problem is particularly prominent in COG packaging. Nationstar Semiconductor took the lead in developing its own patented solder-free process to solve problems such as chip drift caused by uneven solder paste usage and improve the stability of customers' packaging processes.

4. High-precision binning scheme to improve light and color consistency

In order to improve the light color consistency of the Mini backlight module and eliminate the mura effect, Nationstar Semiconductor and strategic partners jointly developed a chip-level high-precision light mixing solution. Through special algorithms and arrangements, the backlight module can achieve uniform light mixing, eliminate the difference in backlight effects caused by the light color difference of the chip, and improve the backlight display effect of Mini LED.

4. Innovation leads the way to create high-definition displays

Nationstar Semiconductor attaches great importance to the role of independent research and development and intellectual property rights in promoting corporate development. As of February 2021, it has applied for 23 Mini LED-related patents. In the next step, Nationstar Semiconductor will continue to adhere to the "3+2" product strategy, continue to focus on the development of Mini backlight and Mini display chips, and actively expand the research and development and application research of Micro LED chips. At the same time, under the leadership of Nationstar Optoelectronics, which adheres to the innovation-driven development strategy, it will increase its efforts in scientific research and innovation, give full play to the core advantages of independent innovation, and unswervingly follow the path of innovation and development.