※AR/VR lens system
Pancake Lens: How Apple Will Mount It
>Fresnel lenses have been used to solve the chromatic aberration distortion caused by the lenses of VR devices, but in order to increase the viewing angle, the focal length becomes longer, which increases the distance between the display and the eyes. As a result, the headset has to be made larger. In addition, there is a phenomenon of ring-ring patterns peculiar to Fresnel lenses or a light-blurring phenomenon called “godray”.
>The folding/array optical method is emerging to overcome the limitations of the existing VR lens method, and the pancake method is a subclass of this folded/arrayed optical method.
>The pancake lens method uses polarization-based reflection to fold the optical path into a small space
> The focal length is significantly narrowed compared to the conventional method, making the headset device thinner and lighter
>The pancake lens method is a name that refers to a lens system using a folding method, so it does not refer to a specific method or a specific type of lens itself.
>Applying the pancake lens method reduces the size and weight of the device, which is advantageous in terms of comfort, but it is difficult to secure an ultra-wide-angle view, and has low contrast with dark images due to low light efficiency
Advantages: By refracting and reflecting light several times, the focal length can be drastically reduced, making it possible to make light and small devices.
Disadvantages: A lot of light is lost in the process of refraction, so it looks dark.
Solution: Use a very bright display! (Why MicroOLED's luminance is so important)
*array lens
Multiple shots of the same combination are combined with an algorithm to improve resolution
*Meta (Facebook) is developing holocake (holographic + pancake)
*Metalens
By erecting nanopillars on the disk, the desired wavelength of light is sent in the desired direction. Color improvement, lens height can be lowered.
♬The above article was also published on https://t.me/timesight.
