An image-capturing contact lens would need to integrate tiny, thin chips, wires, antennae and other miniature hardware, either bonded on top of or embedded within contact lens material. According to Google's patent, each one would at the very least include a control circuit, a sensor and a camera (referred to in the patent as an image capture component), although more components may also be incorporated. The internal components might be connected using embedded wires, wirelessly, or a combination of the two.
The image capturing component would need or a sensor that can take in light and convert it into digital data. This could be achieved with a complementary metal-oxide-semiconductor (CMOS) image sensor, a charge-coupled device (CCD) image sensor.
The other embedded sensors listed in the patent include:
- photodiodes (which sense light)
- pressure sensors
- conductivity sensors
- temperature sensors
- electrical field sensors
- micro-mechanical switches
A control circuit would be required to incorporate the various components to make the image capturing contact lenses work. This circuit would have a processor that would likely be made up of an imaging control component to instruct the camera hardware how and when to capture image data; an analysis component for processing the raw image data and generating metadata about things detected in the captured images; and an interface component to exchange instructions and data with remote devices.
Another necessary circuit control component is power. The lenses would have to include some way to receive (or generate), store and distribute electric power to the internal hardware without being wired directly to an outside power source. (We can all agree that power wires attached to contact lenses would not be practical.) Energy can be transferred from the outside via RF (radio frequency) waves, or the sensors might even be able to generate energy themselves and send it to the power component. The patent lists the following possible power components:
- solar power source
- radio frequency (RF) power source
- electrochemical power source
- temperature power source
- mechanically derived power source
The circuit control would also incorporate transceivers (components that can transmit and receive data) to facilitate the exchange of images, commands or other information between internal components and external devices. The transceiver could include an RF antenna, according to the patent. Another likely component is a data store for saving data or instructions from the internal components or remote devices.
The smart contact lenses may also include a display and possibly light emitting diodes (LEDs) to provide output to the wearer. For a display to work, the lenses would need to include various sorts of micro-lenses (possibly refractive, diffractive or hybrid lenses) to focus the images and make them appear to be suspended at some distance in front of the user. One possibility mentioned in the patent is a liquid crystal lens, which is a variable-focus refractive lens that can be altered with application of an electrical signal. Another mentioned is a Fresnel lens, which is a diffractive lens that doesn't quite have the image quality of a refractive lens but can be made much thinner.
The system could work with one contact lens alone, or two contact lenses with identical or different distributions of components. With just one contact lens, the user would be able to capture images within view just fine since our two eyes move in conjunction with each other for the most part. With two contacts, the user could potentially capture 3-D images.