Smaller and simpler lens-free cameras could have cameras smaller than a pencil point that cost pennies each

Lens-free camera are being made that are 200 micrometers across which is smaller than a pencil point. When you take a picture of a painting on a wall with a regular digital camera, a lens focuses each point of light it captures on a sensor, generating a digital file that a computer can show you as an image. Rambus’s approach instead uses a grating etched with a spiral pattern through which light can enter from every orientation. The sensor below the grating captures a jumble of spirals that a human wouldn’t see as a recognizable image, but software can translate into one.

Gill uses the Mona Lisa image to demonstrate. He shows me a regular black-and-white image of the painting, a blurred black-and-white form indicating the jumble of spirals the sensor would capture for the computer to interpret, and a blurry but still recognizable black-and-white image of the painting as reconstructed from this data by software.

Gill says Rambus’s algorithms let users ask the computer to produce images at various resolutions; the highest he’s done thus far with prototypes is 128 by 128 pixels, which he says represents the capabilities of the highest-resolution sensors Rambus would make if it commercializes the technology.

Eventually, tiny cameras can being built into all kinds of things, from wearable gadgets to security systems to toys, without having to add to the cost or bulk of a camera with a lens. “Our aim is to add eyes to any digital device, no matter how small,” he says.

The point is not to build high-resolution cameras like you’d want on a smartphone but rather to build the smallest, cheapest, easiest-to-make optical sensor that can still capture enough information to show what’s going on.

While there are other lensless camera projects out there, such as one created by Bell Labs, Gill believes the one Rambus is working on is less complex and can be made much smaller. The technology used to make it is similar to the CMOS technology used to construct computer chips, so it could be manufactured within an array of chips while adding just a few cents to the overall cost of each chip.

Rambus’s lensless camera uses a spiral-etched grating to capture light. Shown here, next to a coin for size comparison, is a prototype of a grating that sits atop a sensor.
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