From a visual perspective, the overarching goal in VR development is to be able to show virtual worlds that are indistinguishable from the real world – creating a fully immersive experience and complete sense of presence in a different place. A neat phrase that captures this goal and has been popularised by Meta and others recently is “passing the visual Turing test” – an aspirational goal that is achieved when the user cannot distinguish virtual content from the real world.
Whilst no VR headset is yet close to the point where it could pass such a test, the AR/VR market continues to grow as successive product generations incorporate optical performance innovations – from the displays that generate the images to the optics that convey and manipulate the image before it enters the eye. Naturally, for a wearable mobile device, any new innovations must also be designed to minimise weight, size and power consumption. Headsets should feel so comfortable for the users so they almost forget they are wearing them. Only then can users fully immerse themselves in the virtual world.
Reducing headset weight
A typical pair of regular sunglasses today weighs around 35g. Current AR/VR headsets tend to be 10-20 times heavier. The distribution of that weight with respect to the neutral position of the head is also a key consideration. Unsurprisingly, studies show that having a significant portion of the weight in front of your face (where the displays and optics usually are for VR) is more noticeable and more tiring than it being close to the neutral position of the head.
The good news is that successive generations of headsets are getting lighter as well as higher performance. One such new technology that will further reduce weight and increase performance is flexible LC optics – ultra-thin and light liquid crystal cells that can actively focus, steer and modulate light. These active films save weight and space in exactly the places where it’s most impactful. For example, tunable liquid crystal lenses allow the user to see focussed images at whichever depth they choose to look in the virtual world. Building these optical components on 40-micron bioplastic films instead of conventional glass makes them around ten times lighter and allows the film to 3D conform to the surface of other fixed optics, saving further space and minimising internal reflective losses.
Whilst the idea of passing the visual Turing test is about convincing our eyes, we should not forget about convincing our neck as well – and ultra-thin and light LC optics for VR as well as AR are a key part of enabling both.
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