MICRODISPLAY SUPPLIER KOPIN CORPORATION—which specializes in wearable headset products for the military, industrial, enterprise, and consumer markets—says it shipped the first production order of its 720p color OLED microdisplays to a US company for public safety applications. The 0.49-in.-diagonal 720p display uses the combination of Kopin's proprietary ColorMax technology for superior color fidelity and a duo-stack OLED structure (which is essentially two layers of OLEDs) for high current efficiency and low power consumption. Kopin makes microdisplays used in everything from helmet displays for fighter jets to smart glasses for running and cycling. It has historically manufactured its own active-matrix LCD and liquid crystal on silicon (LCOS) displays, but it is pursuing a fabless model for its OLED products. The 720p-color OLEDs are made by the Chinese firm Lakeside Optoelectronic Technology at its factory in Changzhou, China. “We are very pleased with our first production order of our color duo-stack 720 OLED microdisplays, which is for a product made by a US company,” John C.C. Fan, CEO of Kopin, says in a press release. “Though this initial order is fairly modest in size, it is an important milestone for our OLED microdisplay business, and is a true proof-point of our fabless OLED display business model in which our OLED partner, Lakeside, manufactures the displays on our ColorMax backplane wafers to meet our specifications. With the successful production of duo-stack color displays on our ColorMax wafers, we believe it will be the first of many orders from companies around the world that want to leverage our industry-leading technology.” Kopin's color display is made with a duo-stack white OLED structure and color filters. The company's patent-pending ColorMax technology uses a specially configured anode structure in the silicone backplane to suppress color mixing among tiny subpixels (2.8 × 8.4 micrometers in the 720p display), which be problematic would otherwise in duo-stack OLED structures. Duo-stack is Kopin's strategy to improve luminance, a long-time challenge in using OLED microdisplays for augmented reality applications, says Guillaume Chansin, director of display research for Display Supply Chain Consultants. “When you're going to overlap an image in front of the reality, you want that image to be bright enough so you can see it, especially in bright daylight,” Chansin says. “The OLED technology that has been available so far was not bright enough, so now what companies like Kopin are doing is to find ways to push the brightness up.” Other microdisplay firms are taking different approaches, such as Hopewell Junction, New York-based eMagin Corporation, which uses a technique called direct patterning in its OLEDs that produces red, green, and blue (RGB) light without requiring a color filter. Both Kopin and eMagin have achieved more than 7,000 nits with their OLED microdisplays. Chansin says it remains unclear, though, which technical approach is superior for mass-market consumer devices. He notes that Sony is also a big player in OLED microdisplays, but it has yet to disclose a particular strategy for improving brightness. “It's really hard to tell at this point, because this problem has been around for quite a long time and a lot of people have come out with ideas to do a brighter OLED,” Chansin says. “But we still don't know what the limit is. Both companies [Kopin and eMagin] say they want to go to something like 30,000 nits eventually.” In the near term, other opportunities exist for OLED microdisplays in virtual reality (VR) headsets, where brightness may not be as much of a key requirement. Kopin has already worked with Panasonic to produce micro-OLED panels for prototype ultra-high definition (UHD) VR goggles. The 1.3-in. panels, which feature high dynamic range and 2.6K (2,560 × 2,560) resolution, work in combination with 3M's Pancake optics to create a lightweight goggle suitable for VR sports or entertainment applications. —Glen Dickson Kopin's Microdisplay A 0.49-in. diagonal 720p OLED display incorporating ColorMax technology. source: Kopin
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