To develop Micro LED display technology, which is often regarded as the most promising display technology after OLED, Taiwan’s contract manufacturer Hon Hai Precision Industry, better known as Foxconn, recently announced that it will invest around US$10 million to acquire U.S. startup eLux through subsidiaries including CyberNet. After completing the acquisition, CyberNet will hold a 45.45% share in eLux; Innolux 13.64%, and Advanced Optoelectronic Technology 9.09%. Foxconn group companies will become the largest shareholder of eLux.
According to LEDinside, a division of TrendForce, eLux was founded in October 2016. It was registered in Delaware but is actually located in a small town called Cama (WA/ USA). eLux has had a long history with Japan’s Sharp. Both CEO JJ Lee and CTO Paul Schuele were members of Sharp Laboratories of America; even the addresses of the two facilities are completely the same.
So, how come Foxconn is interested in this 7-month old startup with only 10 employees?
Currently, there are four types of technology for transferring Micro LEDs: Van der waals force, electrostatic adhesion, laser ablation, and phase change. Most manufacturers adopt the first three technologies. eLux, however, has patented technologies focusing on phase change repair and transfer, which are quite different from rival companies.
In its patents, eLux mentioned several times the high cost of Sony’s CLEDIS. To address this issue, eLux applied for a patent related to fluidic assembly and positioning. The patent has two key features: the first is using the height differences among each micro component to conduct forced positioning in certain areas. This will ensure uniformity in velocity component and maximize assembly speed. The second is following assembly, the non-defective items will not be removed but those that are misaligned or misplaced. This technology ensures low-cost, high-speed assembly that can help achieve an extrapolated assembly rate of over 56 million units per hour.
In addition, based on LEDinside’s analysis, eLux also has patented technologies regarding Micro LED display lighting management system, system and method for emissive display repair, Micro LED display with printed light modification structures, and display with surface mount emissive elements.
In our opinion, these patents not only touch on related patents proposed by other companies but also include display repair, suggesting that eLux has moved one step closer to mass production. In the past, manufacturers only aimed for product demonstration; now they are trying to get their products out there. This time, eLux moved even further to repair. Another thing that is worth noting is eLux’s patents mainly cover large screen display, which may help increase Micro LED adoption in outdoor signage.
Considering the long-standing relationship between Foxconn and Apple, and eLux’s comprehensive patent coverage, one would naturally associate Foxconn’s move with Apple’s decision to acquire LuxVue. However, although the LuxVue acquisition has led to a Micro LED craze, LuxVue, eLux, and infiniLED acquired by Facebook are all small startups. Judging from this, we believe the development of Micro LED is still at the early stage.
Related Patents
Color Conversion
This patent is about system and method for light color conversion and scattering of the light generated from individually addressed emissive elements in a Micro LED display. To fabricate a full-color Micro LED display, one method is using blue light-emitting LEDs for all subpixels, with quantum dot color conversion technology to be RGB subpixels. A color conversion scheme utilizing quantum dots can be applied to subpixels for a high-definition display. Thus, eLux proposed a patented technology for making multi-color emissive display utilizing quantum dots. One advantage of QDs is better conversion efficiency and color emission in narrower wavelength bands, giving a wider color gamut than conventional phosphor.
Pick-and-Place Transfer Technology and Method for Emissive Display Repair
This patent presents a process by which a relatively low number of defects resulting from fluidic self-assembly of a display can be systematically identified and repaired. After transferring a substantial number of Micro LEDs to a substrate, UV illumination and inspection an optically filtered inspection process are used to determine defect Micro LEDs. Then comes the pick-and-place stage that includes a robotic device and liquid phase technology.
The pick-and-place transfer head is coated with a liquid phase polymer and connected to electricity to heat up. When contacting a defect item, the transfer head will be cooled by liquid, and the polymer will be converted to a solid phase attached to the defect item. Afterwards, the defect item will be attracted to the transfer head in response to the electrostatic charge; subsequently, the surrounding area will be cleaned. Lastly, the robotic device will adhere functional Micro LEDs with electrostatic charge and put them back on the array sites to complete the repair process.
Optical Design
This patent talks about the structural features used with Micro LEDs, which control the directionality of light emitted. The purpose is to control the direction of the light emitted by each Micro LED to reduce light leakage between pixels to improve color quality and contrast. The light from each Micro LED is emitted from all surfaces and is thus emitted in directions vertical and parallel to the display surface. If it is not controlled, the light emitted along the direction nominally parallel to a transparent display substrate surface will spread to adjacent pixels.
Micro LED Display Assembly with SMT Process
This patent describes the method of using Micro LEDs to fabricate large scale, high dynamic range display with acceptable cost and high reliability. Micro LEDs are fabricated on a sapphire substrate by etching. Disks are processed to form separate anode and cathode electrodes on the top surface of the Micro LEDs. The resulting Micro LEDs are released by a laser lift off process and then form a suspension in a suitable liquid. This suspension is deposited on a display substrate that has been prepared with an array of well structures with two electrodes that match the anode and cathode electrodes on a Micro LED disk. An array of Micro LEDs in a surface mount configuration can be fabricated by fluidic assembly to make high dynamic range display.