What They Say
IEEE Spectrum published an article about the work being done by a start-up, Mojo Visio of Saratoga, California, to develop imagers and processing chips for use in contact lenses. The AR lens is intended to help those with low vision by adding:
- zooming
- contrast enhancement
- edge detection
- identification.
One of the challenges is in having to be extremely low power – and the image processor and imager must consume little more than about 100 microwatts each. They must also be small enough not to cast appreciable shadows on the user’s retina.
The firm decided that 256 x 256 in monochrome was enough for the job, but conventional architectures couldn’t do it. To quote the article:
Mojo Vision’s answer was to replace the bank of power-hungry ADCs with a set of capacitors that passively store the read out charge from the pixels. The capacitors are then sequentially selected, amplified, and fed to a shared ADC in a way designed to avoid errors. The combination saves both power and area, resulting in a 1.3 mm² chip—perhaps the smallest of its type—that consumes no more than 61-95 microwatts depending on frame rate and bit resolution.
The image processor circuit consumes a maximum of 111 microwatts and occupies just 0.21 mm² of a larger chip.
There’s a separate article that covers an interview about the firm’s ambitions.
What We Think
The idea of contact lens displays still causes me trouble as a concept, but for those with this kind of impairment to their vision, it could be very, very attractive. (BR)
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