Recently because apple will use AMOLED screen, make fire a handful of OLED concept. And is considered to OLED display for the next generation of Micro - LED also seems to be no longer a low profile, in Taiwan honor international seminar on solid-state lighting colour. Compared with OLED, Micro - LED technology is unfamiliar to many people, but pay attention to more and more high. Small make up today about the Micro - LED concept, the advantages and disadvantages, the current situation and technical bottleneck to explanation, what is the wrong place to welcome you all to discuss.
What is Micro - LED?
Micro LED technology, namely, LED miniaturized and matrix technology. Refers to the integrated on a chip high density small size of the LED array, such as LED display each pixel can be addressed, drive light alone, but as a microcosm of the outdoor LED display, the pixel distance from millimeter level down to micron level.
And Micro LED display, it is the underlying made from normal CMOS integrated circuit manufacturing LED display driver circuit, and then made the LED array MOCVD machine in integrated circuit, so as to realize the Micro display, known as the miniature of LED display.
Highlight the advantages of
Micro LED performance advantage obviously, it inherits the inorganic LED high efficiency, high brightness, high reliability and fast response time, etc, and illuminated without back light of the features, more energy saving, simple structure, small volume, thin and other advantages.
In addition, Micro LED a big feature is high resolution. Because of ultra-small, particularly high resolution; It is said that if apple iPhone6S using micro LED, can easily reach more than 1500 ppi, resolution than the original of the Retina display 400 ppi is 3.75 times higher
And the colour more accurately than OLED debugging, longer life and higher brightness and having better material stability, long service life, brand image, etc. Reason for OLED after another light and energy saving advantage of display technology, with the OLED convergence is also need to TFT back drive, therefore, IGZO, LTPS TFT technology level for Oxide.
There is the disadvantage of
1, the cost and the disadvantage of large area application. Driver circuit is dependent on the single crystal silicon substrate, and released from a previous apple patents, a shift from sapphire substrate LED to step on the silicon substrate, means making a screen at least need two sets of substrate and independent of each other. This leads to the rising cost of, especially the widespread application, will yield and cost there will be a huge challenge. (for single crystal silicon substrate, a couple of inches is the large area, with reference to the whole picture and larger cutting of CMOS sensor product price), of course, from a technical perspective LuxVue converts driving circuit substrate to quartz glass or to reduce the widespread application cost is feasible, but it also takes time. Mature than AMOLED LTPS + OLED, cost no advantage.
2, luminous efficiency advantage by PHOLED threat, even surpassed. Phosphor to promote the efficiency of OLED (Phosphorescent OLED, PHOLED) visible, UDC company's red and green PHOLED materials are already in the samsung GalaxyS4 and subsequent machine begin commercial operation panel and the panel has high and PPI TFT - LCD power consumption a draw or a slight advantage. Once the blue PHOLED material of problem solving and commercial life, inorganic leds will also take advantage of less than on efficiency.
3, brightness and life expectancy was QLED threat. QLED research is very hot now, from the perspective of the data of QD Vision provides both efficiency and life span is very promising, and engaged in the research of big companies are many. QLED, of course, is also the OLED powerful competitors.
4, it is difficult to make curl and flexible displays. OLED and QLED prospect of flexible displays is very good, already has a lot of Prototype show, but for LuxVue make curl and flexible seem more difficult. If you want to manufacture products such as iWatch, screen without certain curvature is does not conform to the aesthetic.
The status quo
Of micro LED to the development of the status quo, as Nouvoyance CEO is samsung OLED panel P arranged pixels founder CandiceBrown - Elliott said, before apple purchase LuxVue only few people know and engaged in the field, and now there are a lot of people started talking about the technology.
And two Micro - LED technology experts in the last year has said that the technology application level is difficult to produce all kinds of useful screen panel, recently is unlikely to see in the iPhone, the device or the iMac products the screen technology. But for smaller screens, Micro - LED is still a viable option, like Apple Watch, etc. The application of the small screen.
Actually since LuxVue was apple's revenue, see VerLASE company announced to get breakthrough color conversion technology patent, the technology can make full color MicroLED array is applicable to close eye display, after there has been no relevant report. Recently, LEDinside got the news from Taiwan solid-state lighting seminar recently, Leti, University of Texas (Texas Tech University) and PlayNitride unfolds own microLED r&d achievements in the seminar.
Leti launched iLED matrix, the blu-ray EQE9.5 %, 107 CD/m2 brightness; Green EQE5.9 %, 108 CD/m2 brightness, full-color display is realized by using quantum dots, the Pitch of only 10 um, future goals do 1 um. Leti short-range plans from smart lighting, medium-range 2-3 years into the HUD and HMD market, grab a VR/AR hot, long-range goal is 10 years into large size display applications.
Also released and Taiwan Play Nitride based on gallium Nitride PixeLEDTM display technology, the company through transfer technology transfer to the panel, transfer yield could reach 99%.
Thus, Micro LED technology has a lot of enterprises in follow up, and the faster development. But judging from apple itself, which belongs to the apple laboratory technology, and apple itself also bet on a lot of new industries, so the future import production remains to be seen.
The bottleneck of development
In fact, the core of the Micro LED technology is nanoscale leds transhipment, rather than making LED the technology itself. Due to the lattice mismatch, LED micro device must first be in sapphire substrate by molecular beam epitaxy growth. And make it display, must transfer LED micro devices to glass substrate. Because of making LED micro devices sapphire substrate size is basically the size of silicon wafer, and make displays is much bigger size glass, therefore the need for multiple transshipment.
For micro devices transfer technical difficulties are particularly high for many times, and used in the pursuit of high precision monitor product is more difficult. Through the apple bought Luxvue announced after obtaining patent list also to see, mostly adopts the electrical method to complete the transfer process, so it is the key to Luxvue core technology
Taiwan år gen executive Li Yunli recently also said: "there are two key to success: Micro LED one is apple, samsung, these brand factory wishes; second, wafer lift technology, a carry millions of super small LED chip, a threshold to overcome."
Actually, Micro LED also faces the third question, namely, full-color, yield and luminescence wavelength consistency issues. Monochrome Micro LED driver IC encapsulation and amplifies the array by inversion structure can be achieved, but times RGB array need to re-post red, blue, green grain, need to embed the hundreds of thousands of LED grain, grain for LED lights, consistency of wavelength, yield more demanding, at the same time points bin cost is also hinder the production of technical bottleneck.
