Apple, an iconic brand in the technology industry, reported this year that it will increase its investment in Micro LED research and development in Taiwan. At the same time, there are constant news that Apple will launch iPad and MacBook products using MiniLED technology in 2020 and 2021. All walks of life are optimistic that, driven by major manufacturers, more brands will be attracted to introduce MiniLED display technology, which will drive demand to rise.
As MiniLED and Micro LED display technologies continue to evolve, and the size of LED chips is becoming more and more refined, TrendForce's LED Research (LEDinside) has proposed the latest MiniLED and Micro LED definition standards for the current industry specifications, as well as the current two Technical progress and problems.
Origin and definition of Micro LED and MiniLED
Micro LED display technology miniaturizes the traditional LED design structure to the micron/μm level, removes the sapphire substrate, and arrays these tiny chips to become display pixels that can be driven by a single drive to achieve high brightness and low energy The display effect of high power consumption, high resolution and high saturation.
The prototype of Micro LED technology comes from the Crystal LED Display released by Sony in 2012. It uses 6.22 million Micro LEDs on a 55-inch display to create high-resolution display pixels.
However, the production method at that time was made by a single LED embedded method, which was time-consuming and laborious, and also highlighted the key manufacturing problems of Micro LED.
Therefore, Taiwan LED manufacturer Jingdian proposed the concept of Mini LED, which also reduces the size, but retains the sapphire substrate, so it can still be made with existing equipment. The production difficulty and cost are lower than that of Micro LED, and it can be commercialized as soon as possible. market.
In the past, LEDinside used 100 micrometers (micron/μm) as the size boundary between Micro LED and Mini LED, and defined chip sizes above 100 micrometers as Mini LEDs and micro LEDs with chip sizes less than 100 micrometers. However, due to the recent continuous development of related technologies, manufacturers have been able to manufacture MiniLED products with a size of less than 100 microns but still with a sapphire substrate. Therefore, LEDinside re-defined the size of Micro LED to be less than 75 microns without sapphire substrate.
Micro LED and MiniLED technology characteristics and current technical challenges
Although some people thought that MiniLED was the transitional stage of display technology's evolution towards Micro LED, as MiniLED gradually matured, it began to step out of its market positioning. It is currently mainly used in multi-zone backlight displays and large RGB small-pitch displays.
In terms of backlight applications, MiniLED backlight displays can be dimmed in a full matrix manner, such as low-resolution black-and-white images, enhancing the high-contrast and high-resolution display images to achieve HDR effects. At the same time, the chip size of MiniLED continues to be revised down, which can increase the light control area and make the picture more detailed.
Another major application of MiniLED is RGB small-pitch displays. Small-size package MiniLEDs are used to create large-size display screens with a display pixel pitch of less than P1.0mm, which has the opportunity to create new mainstream display specifications.
Regardless of whether it is partitioned backlight display technology or RGB small-pitch displays, the number of MiniLED chips used has increased by tens of thousands of times compared with traditional applications. Therefore, the requirements for detection and sorting of chips and subsequent transfer of pieces have been greatly improved. Traditional pick and place technology Although Pick & Place can still be used, the yield and speed are not as good as new equipment. Jingdian, which has substantially expanded its plant this year, is focusing on the subsequent process, purchasing a large number of transfer printing equipment, as well as sorting and testing machines, with the purpose of accelerating MiniLED mass production.
Micro LED display technology under continuous research and development may create new application areas. Micro LEDs that remove the sapphire substrate and are more compact will not only be thinner and lighter, but also have the opportunity to be integrated on different materials. Display applications that are currently receiving much attention include AR/VR devices, car screens, and high-resolution wearable products.
In order to further realize the dream of Micro LED display products, the goal of manufacturers at this stage is to continuously optimize technology and reduce production costs. As the size of Micro LED chips is more reduced, the luminous efficiency needs to be enhanced, and the ultra-small size is difficult to handle with existing equipment. Therefore, whether it is LED manufacturing, transfer, testing, etc., it depends on the alliance and cooperation of upstream and downstream manufacturers. If you can expand with semiconductor material and equipment manufacturers, you have the opportunity to get twice the result with half the effort.
