Solid-state cameras are everywhere, from smartphones to door bells to baby monitors, and a host of other devices. But they all have something in common: a lens to focus light on the tiny imaging chip. In relative terms, the lens is enormous compared with the sensor. Rambus is a company originally known for its novel memory chip designs, but the firm now creates a variety of semi-conductor products and designs, has come up with a camera chip that does not require a lens.
The secret to the design is a special “binary diffraction grating” that is the same size as the sensor chip. The image above shows the “blob” of data that the sensor receives through this asymmetrical pinwheel-shaped grating. The trick is that this information is then processed by sophisticated algorithms to recreate the image. By comparing sequential frames, the device is able to infer a fairly detailed image of an object passing by the camera. The chip is inexpensive to produce and draw very little power, and so can be incorporated in all sorts of devices such as power outlets or smoke detectors in the home, or the frames of eyeglasses, or streetlights and other outdoor fixtures. The images can be used to detect and identify people moving in a room, or to recognize gestures to control electronic devices. And all this is contained in a package that is less than a millimeter thick.
This technology also points to a larger development in sensors and wearable technology in general; developers are creating algorithms that are very effective at extracting useful information from noisy data streams. These developments will lead to simple sensors being used for increasingly sophisticated applications as we rely on software to make sense of the sensor outputs.