Why is the core technology of VR headsets said to be optical lenses?

Why is the core technology of VR headsets said to be optical lenses?

With any VR headset, when you look inside the circular blackout goggle case, you'll find two things: a screen that displays the virtual world; and a set of lenses in front of the screen. Most people focus on the display part of the headset, what is the resolution? refresh rate? What about contrast?

However, the lens located in front of the screen is equally important. Why are optical lenses an important part of VR headsets, and how do they affect the quality of the VR experience?
Why is the core technology of VR headsets said to be optical lenses?
Speaking of lenses, and how they will affect VR headsets, the first thing we need to focus on is display size. The larger the size of the VR headset, the more view it blocks and the wider the field of view. But if the display is too large, the overall device may be too bulky. From this perspective, the smaller the display, the better.

One solution to this problem is to bring the screen closer to your eyes. There are two benefits: first, you don't need a larger monitor to get a wider field of view; second, according to Archimedes' principle of leverage, the closer the monitor is to your face, the less force it has. Unfortunately, you get uncomfortable when focusing on objects that are too close, which limits how far you can set the display.
Why is the core technology of VR headsets said to be optical lenses?
It raises a question. Under normal circumstances, our field of vision can reach 180 degrees. For reference, current head-mounted displays are likely to be around 7 inches (18 cm) diagonally and as close to the eye as comfortably, this screen has relatively little field of view. Therefore, users need to perceive your virtual world from a very narrow angle, just like using an eye patch in the real world.

Part of the solution to this problem is to have a lens and a series of lenses between the face and the display. Our goal is to refract light, essentially using the lens of a magnifying glass to provide a wider field of view. You can also move the monitor to an area that is usually uncomfortable for the eyes, and the right lens will make the view more comfortable.
Why is the core technology of VR headsets said to be optical lenses?
Then a factor is the presence of artifacts or aberrations in the optical lens. A prism is a type of lens that acts like a prism and separates colors when refracting light, which is called chromatic aberration. We need to be aware of other biases. Spherical aberration causes different parts of the image to focus on different points, which means that if you want the center of the image to be sharp and sharp, the edges will become increasingly blurry. This is followed by barrel distortion and pincushion distortion. This usually happens when the lens is trying to correct both of the above distortions and trying to create a wide field of view, which will cause the mesh to stretch or squeeze.

But when you try to expand the field of view through the lens, you will face the aberration problem described earlier. Camera lenses solve this problem with a complex stack of lenses, trying to remove all aberrations and give you a clear, undistorted photo. Unfortunately, this series of lenses will add weight and length to the overall device, as well as a considerable portion of the cost.
Why is the core technology of VR headsets said to be optical lenses?
That's all for today, thank you for your patience in reading!

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