Luminous MicroLED on Silicon screens are in development by Samsung for augmented reality headsets
Due to their quick response times and deep blacks, OLED screens have been employed for some time in VR headsets. Samsung’s own Gear VR used OLED (as part of the Galaxy phone that powered those headsets), as did the specialized Odyssey VR headsets, and the first Oculus Rift CV1 used OLED as well as certain later variants.
Kim Min-woo, head of Samsung’s display division, recently told The Elec. that the company is working on next-generation technology for augmented reality displays based on MicroLED. In particular, this is a phenomenon known as MicroLED on Silicon, or “LEDoS” for short. Displays these days are often manufactured on a glass substrate rather than silicon.
The displays used for Augmented Reality (AR) need to be brighter than those used for Virtual Reality (VR) because AR blends virtual items into the real environment, and to do so effectively, it needs to match the brightness of the light around the user. Since virtual reality screens isolate the user, less light is sufficient.
Samsung intends to eventually create LEDoS screens with a pixel density of 6,600 per inch (PPI). According to Kim, augmented reality displays need at least 5,000 pixels per inch (ppi) and a pixel pitch of 5 micrometers or less. Each of the sub-pixels for red, green, and blue needs to be no bigger than 3 micrometers.
To put that in perspective, the displays on the original Odyssey VR headset were only 615ppi, while Samsung touted a “perceived” pixel density of 1,233ppi using technology it created to combat the screen door effect (even though the resolution of the display remained the same). This happened long ago, but it demonstrates how far we still have to go before we can create a truly lifelike image using current technology.
Kim claims that in addition to LEDoS, Samsung Display is also working on OLED on Silicon (OLEDoS) screens. However, microLEDs are expected to be brighter, making them a better fit for augmented reality uses.
To achieve the level of realism required for rendering outside scenes, Meta is developing prototype headsets with brightness levels of up to 10,000 nits. That’s five to ten times as luminous as the greatest smartphone screens now available. To provide even more light, the most recent Meta Quest Pro employs LCDs with local dimming (500 LEDs for each backlight).
