Researchers at ETH Zurich have developed an entirely new type of pixel that can simultaneously register and display light. Such bidirectionally functional pixels could in the future be used in hybrid devices that combine the functions of a camera and a screen.
The term “picture element”, later shortened to “pixel”, first appeared almost 100 years ago in the American technology publication Wireless World. Today, pixels are found almost everywhere, but they have clearly divided roles. They display light information on the screens of phones, computers and televisions, while cameras register light. Until now, they could not perform both functions.
A team led by David Norris, a professor in the Optical Materials Engineering Laboratory at ETH Zurich, has changed this division by developing pixels capable of simultaneously generating and analyzing light.
The new type of pixel combines the functions of a light sensor and a screen
New pixels can direct light and analyze its properties. In addition to the intensity, it is possible to control and examine the oscillation phase and the polarization of the light. According to the researchers, this technology could in the future enable the development of devices that combine the camera and screen into a single unit.
The research was presented in the scientific journal Nature, and is based on the interference of light waves. When light is scattered from a surface, the waves originating from different points overlap each other. The shape of the surface determines the phases of their oscillation, so waves with equal phases reinforce each other, while waves of opposite phases cancel each other out.
ETH ZurichThe team used this physical effect to control light using specially shaped wavy surfaces. The pixel converts the incoming light into a surface wave that moves across the surface of the chip.
Elsewhere within the pixel, the surface wave is again scattered from the material as a light wave. By interfering with these waves, it is possible to create patterns and images.
Using Fourier analysis, researchers can determine what the final image will look like, as well as the exact surface pattern needed to form it.
According to the explanation of ETH Zurich, the new pixels could react to the detected image and produce the corresponding light display without the help of a computer. The short-term goal of the researchers is to develop a matrix of Fourier pixels, which could enable the creation of complex devices with unified camera and screen functions.
This means that the entire surface of the screen could register the incoming light and then form an image on the same surface. The camera would no longer have to be separated as a hole, a sensor under the screen or a separate module. ETH Zurich just lists such hybrid “camera-screen” devices as a major future direction of application.
The technology has already led to the filing of a patent application, and the project is in competition for this year’s Spark Award, reports PetaPixel.