Unique all-plastic Pancake optics for OLED display

Kopin® Corporation, a leading developer and provider of high-resolution microdisplays and display subassemblies for defense, enterprise, consumer and medical products, has developed a new all-plastic Pancake® optics for its new-generation 1.3” 2.6K x 2.6K Lightning® organic light emitting diode (OLED) microdisplay with outstanding performance for virtual reality (VR) applications. The new Pancake optics (named P80) enables the design of compact, lightweight, stylish VR glasses that are comfortable to wear for extended hours with no need for adjustment, even for people who wear eyeglasses. The P80 Pancake optics provides a very sharp, 77° field-of-view (FOV) image with very long (23 mm) eye relief and large (12-mm-diameter) eye box. Kopin previously announced the world’s first all-plastic Pancake optics with 95° FOV but with a smaller eye relief and eye box.

Pancake optics, compared to other optics designs, can provide far superior magnified image quality in a much thinner form factor, especially for VR headset products with FOV ranging from 50° to 100°. However, previous Pancake optics needed at least one spherical glass lens to avoid image artifacts caused by birefringence of plastic materials, but this spherical glass lens added both weight and cost to the lens system as well as reduced optical design flexibilities compared to aspherical plastic lens. Kopin’s patent-pending two-element Pancake optics design, together with processes to make aspherical plastic lenses with virtually no birefringence, has provided much better image quality, much smaller size, lighter weight and lower cost than anything previously available.

Kopin's P80 all-plastic Pancake optics, optimised for Kopin’s world-leading 1.3" 2.6K x 2.6K organic light emitting diode (OLED) microdisplay (2560 x 2560 resolution), provides an extremely sharp image with excellent modular transfer function even out to the edge of the field of view, a critical and difficult to achieve performance feature for VR applications. Combined with Kopin's 2.6K x 2.6K high-brightness OLED microdisplay, the P80 pancake optics provides a virtual image equivalent to a 180-inch-diagonal display viewed from a 3-meter distance. With the same display operated in a 16: 9 mode, the FOV is 65° (equivalent to 150” TV viewed from a 3-m distance).

The new-generation 1.3”-diagonal 2.6K x 2.6K OLED display on chip (DoC®) is designed with Kopin's extensively patented backplane architecture that reduces power consumption and delivers very high frame rates up to 120 Hz and colour control up to 10 bits (30 full-colour bits). Utilising its patent-pending ColorMax® technology, Kopin has been working with its partner, Lakeside Optoelectronic Technology Co., Ltd., to optimise the duo-stack OLED structure to output colour spectrum to match the bandpass of the colour filters for high colour fidelity (> 100% sRGB), coupled with very high Current Efficiency for high brightness (> 1000 nits). The 30-bit colour control, together with the high colour fidelity, high brightness and high contrast ratio (> 10,000: 1), enables the much-desired studio-quality, high-dynamic-range (HDR) VR experience. Kopin’s 2.6K x 2.6K OLED fully integrated on Si is the world’s largest DoC with unmatched performance.

“It has been our long-term objective to provide critical components for VR headsets which are thin, lightweight, and easy to use – just put it on and no fuss, like regular eyeglasses,” said Dr. John C.C. Fan, CEO and founder of Kopin Corporation. “Our novel P80 all-plastic Pancake optics combined with our new-generation 2.6K x 2.6K OLED microdisplay almost meet such requirements. We understand somewhat smaller FOV is a little curve ball – most folks aim for as large image as possible. However, we believe in the importance of ‘Human First’. We plan on offering our new optics as either a stand-alone component or in a module with our OLED microdisplays. Our all-plastic Pancake optics with very long eye relief and large eye box combined with our outstanding OLED microdisplay that has wonderful colour, 120 Hz operation and 10-bit colour control could spearhead a new era of VR glasses.”