Augmented Reality isn’t a new concept. Entertainment companies have been toying with the idea of stereoscopic and immersive experiences for years. I still remember opening up my Nintendo Virtual Boy on Christmas morning–which I played with once and never touched again! Joking aside, I’m not the only one who has had complaints about these older AR devices. It’s too heavy, or the glasses are too dark, or I get nauseated while using it are some of the most common downsides to these technologies. However, the great thing about getting these things on the market for commercial use is that the feedback from users–both positive and negative–helps the designers of AR technology see the real issues with their products, and lets them know how to improve them.
Researchers at the National Chiao Tung University in Hsinchu, Taiwan, and the Tsinghua University in Beijing have focused on three major optical challenges that AR wearable devices have faced from the first attempts all the way up until today–namely, vision correction, registration and readability under strong ambient light.
Solving these problems is not a simple task, but by using two liquid crystal lenses (LCL) and integrating a polarizer-free attenuator into the AR system, they managed it. The liquid crystals work because they are in constant flux between a crystalline solid state and an isotropic liquid state. They’re typically in the shape of an elongated, rod-like molecule, only a few nanometers in size. When these LCLs are exposed to an electric current, they change their orientation, which varies their refraction index. The voltages are adjustable, which means that they can accommodate both nearsightedness and farsightedness, as well as some other ophthalmological conditions. This way, people who have vision impairments can use the headsets or glasses without having to use their prescriptions glasses underneath.
If you’ve used an AR or VR headset before and you have a vision impairment, you’ve probably noticed this problem before. The screen was not corrected to accommodate your eyes. However, the LCLs change the refraction index of the screen in much the same way that glasses or contact lenses correct the refraction of light as it enters your eyes, correcting the screen so you can view it with 20/20 vision.
The other LCL is used for the task of registration, which is the adjustment that the AR display has to make to portray the position of a visual image over the real thing. The second LCL allows the blending of the AR display and the actual object, as you can see in the video below.
https://www.youtube.com/watch?v=0aOM6ItlFHg&feature=youtu.be
The LCLs can accommodate every eye!
The final problem that we mentioned the researchers addressing is readability under strong ambient light. If you’ve ever tried to read your phone when it’s too sunny outside, this problem won’t be shocking to you. The researchers used an electrically tunable, polarizer-free attenuator to combat this issue. The electrical tuner can adjust based on the intensity of the light in a room, and can change the transmittance of the input light, scattering and absorbing it when there is too much light, and decreasing these features in low light. The system will determine the amount of light necessary for the best picture, and accommodate to the light in the room to allow for the clearest image, eliminating washed-out images even in bright light.
No sunglasses needed.
After looking at these results, it’s clear that there’s a lot that goes into making AR technology usable for people with eye conditions, and in making it versatile enough to use in both very bright and very dark rooms. We know that LCLs aren’t a cheap solution, but the implementation of this idea and knowing that it works is a great first step. Lowering the costs and improving the production volume is another issue, but knowing that the results are possible is promising! We at ARinMED want to see AR technology available for everyone, which means that cost is certainly an issue, but we’re certainly impressed with this progress! We can’t even begin to imagine what sorts of innovations are in store for AR technology in the next few years, but we will be here waiting for each new advancement, and telling you all about them! Let us know what you think in the comments section below!
Source: http://www.nature.com/articles/s41598-017-00492-2
