According to foreign media reports, Facebook recently released a new product news-a concept glasses based on folding holographic optical technology, which proved to be the 'thinest VR display to date'. Facebook's AR/VR Ru0026D department demonstrated two highlights of this new VR display: polarization-based optical 'folding' and holographic lens.
Measurement verification shows that the functional and practical VR display and lens are only 9mm thick, which can be said to be 'VR glasses' in the true sense. In addition to having an incredibly compact size, it can also support a wider color gamut than most VR displays on the market today, and their displays have achieved good results in terms of increasing the zoom resolution to the limit of human vision. progress.In order to focus the light on the eyes, the simple lens in the VR headset must be kept at a certain distance from the display during manufacture, and the folding optics The concept of the element is to 'fold' this distance on itself, so that the light can still travel through the same distance to focus, but its path is folded into a more compact area. For example, for a piece of paper of any width, when the paper is folded in half, the paper itself is still as wide as it was at the beginning, but because the paper is folded in half, the width takes up less space. However, the light beam has a 'direction'. Generally, the direction of the light beam is random, but a polarizer can be used to only pass the light in a specific direction, and then finally shoot it out and enter the wearer's eyes.
This method (also known as 'pancake optics') can move the lens and display closer together, making the headset more compact. Now in order to become thinner and reduce the size of the lens itself, Facebook researchers have abandoned this approach and turned their focus to holographic optics. Simply put, the researchers did not use a series of typical lenses (such as those found in a pair of glasses) in the folding optical system, but made the lenses into holograms.
Different from a photo, it is a light record on the plane of space at a given moment, while a hologram is The record of light within the volume of space. When viewing the photo in this way, only the light information contained in the captured plane can be seen. When viewing a hologram, you can look around because the hologram captures the light information (also called the light field) in the entire volume.But what if there is a lens in the scene captured when capturing the hologram? It turns out that the lens seen in the hologram behaves like the lens in the scene. Therefore, the basic idea behind the Facebook holographic lens method is that researchers effectively 'capture' the hologram of the real lens, condensing the optical characteristics of the real lens into a paper-thin holographic film. The overall goal of this method is to achieve a VR display the size of real glasses, and from the actual situation, this headset is more realistic than 'goggles However, in order to fully focus on the study of optics, Facebook omitted a lot of things inside the headset, such as the light source (in this case, the laser), driving electronics, tracking cameras, etc.