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In this week's devlog update, we're going to dive into the technology behind Bigscreen Beyond's displays and optics.
Displays
Traditionally, VR headsets have used large LCD screens typically used for smartphones. They've gotten higher and higher resolution over the years, starting with 640 by 800 pixels per eye in the Oculus DK1 in 2012 and now 2000 by 2000 pixels per eye for devices like PSVR 2, Vive XR Elite, and HP Reverb G2.
Bigscreen Beyond is the first consumer VR headset that features a breakthrough new technology called micro-OLED displays. These are displays that were made for VR, and they're incredibly tiny. Beyond's displays are merely 18 millimeters wide. And despite being so small, the resolution has also massively improved to 2560 by 2560 per eye or nearly 3 times more pixels than leading headsets like the Valve Index.
Throughout the history of VR until Bigscreen Beyond, you always could see individual pixels and aliasing, sometimes called the screen door effect. This was a distracting effect and provided a low-resolution VR image. Fine text details would be impossible to read. Beyond has solved that, nearly achieving "retina resolution." With Beyond, it's a near true-to-life experience enabling you to see details in VR that were impossible to see before. You can easily see details like fine text, blades of grass, or scratches in metal, enabling you to be even more immersed than you would be with older VR headsets.
The other key part is that these are OLED displays, unlike the LCD displays normally used in VR headsets today. OLED displays provide the best visual experience of any display technology with incredibly vibrant colors, true blacks, and high contrast.
LCD displays have a backlight, which is very slow to turn on and off, meaning you never really get true blacks, and the pixel responsiveness is much slower. Pixel response times are measured in microseconds on OLED, rather than milliseconds for LCD. For VR, you typically need a higher refresh rate to still feel believable. OLED displays feel much more responsive than LCD displays because every pixel can be individually switched on and off within a microsecond. 90Hz on an OLED-based VR headset ends up feeling like 120Hz on an LCD-based VR headset. You can get true deep blacks with OLED, rather than dull greys on an LCD display. OLED provides insane contrast ratios of 500,000:1 and amazing color vibrancy, so everything feels true to life, compared to typical LCD displays with 1000:1 contrast ratios.
Optics
Pancake optics is a groundbreaking technology, offering significant promise for virtual reality. Over the past decade, VR headsets have relied on Fresnel lenses, which were inexpensive, lightweight, and composed of a single lens element typically made of plastic. These lenses were paired with large displays to provide a wide field of view and decent clarity, albeit with artifacts such as god rays.
However, Fresnel lenses are only suitable for larger displays, and as displays get smaller, like the 1-inch micro-OLED display in Beyond, enormous magnification is needed to achieve a wide field of view. This increased magnification would require very large lenses – impossible for the VR form factor – or use of folded path optics. Pancake lenses use polarization to fold light back onto itself through multiple optical elements. This enables large magnification in a very compact size, as well as improved clarity and better optical performance. Yet, enormous magnification in such a tiny form factor comes with tradeoffs. Particularly, it becomes very challenging to have aligned light near the edges of the field of view.
Pancake lenses are more costly to manufacture and require complex machining for accurate production and assembly. We've poured significant research and development in lens design, films, coatings, and manufacturing processes to optimize results, improve field of view and optical performance, and make pancake lenses viable for virtual reality.
One additional aspect to consider is catering to people who wear glasses. Due to Beyond's small form factor, there is no space physically to accommodate glasses. Instead, we manufacture custom prescription lenses for each customer to their prescription. The lens inserts are magnetic and can be easily attached or removed.
"@BigscreenVR continues to amaze me with the Bigscreen Beyond. 😍 Today I received my prescription inserts. Here they are (bottom of pic) compared to my Quest 2 inserts. Quarter for scale! 😂 #VR #VirtualReality #amazingtech" — @AriabelVR
Due to the way pancake optics work, 90% of light is lost as light bounces between lens elements. After years of R&D, this is the first time in history that we've been able to manufacture micro-OLED displays that are this tiny that also have sufficient brightness to be able to be used for VR. Our micro-OLED displays output thousands of nits of brightness. Paired with our pancake optics, the end result is a bright VR image close to what people are typically accustomed to in other VR headsets of approximately 70 to 80 nits to the eye at default settings. Beyond also comes with a Windows-based utility that features an Overdrive Mode allowing people to achieve up to 120 nits to the eye with higher persistence.
Beyond is the end result of years of innovation. Achieving the same field of view as larger headsets like the Meta Quest in a form factor five times smaller and with considerably smaller displays that require more magnification has been a remarkable engineering feat. We're very proud of what we've accomplished and look forward to sharing more technical details in upcoming blog posts.