3D image sensor chips put VR on smartphones

December 18, 2015 // By Graham Prophet
Infineon Technologies and pmdtechnologies have disclosed their REAL3, 3D image sensor chips that will allow mobile devices to quickly and realistically detect their surroundings in three dimensions.

Image sensor chip applications include the spatial measurement of rooms and objects, indoor navigation and the implementation of special photo effects: however, the immediate application is to enable “extremely realistic virtual and augmented reality game experiences” that involve the interaction of the gamer’s own hands and his living environment within the game, via head-mounted devices.

Compared to the previous version, the optical sensitivity as well as the power consumption of the new 3D image sensors has been improved, Infineon says. With built-in electronics that take up little space, the chips make it possible for cell phones to operate mini-camera systems that can measure 3D depth data.

Using microlenses for high sensitivity, the camera’s range and measurement accuracy depend on two factors: on the intensity of the emitted and reflected infrared light, and to a significant extent on the pixel sensitivity of the 3D image sensor chip. The optical pixel sensitivity of the new 3D image sensor chips are now double that of the previous version. For equivalent measurement quality they can work with only half of the emitted light output. Thus, manufacturers of camera systems for mobile devices can not only provide the infrared lighting more cost-effectively, but the camera’s system power consumption is almost halved.

The improved optical pixel sensitivity is the result of applying one microlens to each of the pixels of the 3D image sensor chip. Consequently most of the incident light is directed to a pixel’s sensitive surface, so virtually no light energy is lost to the inactive areas.

The 3D image sensor chips to be showcased at the (January 2016 Consumer Electronics Show) were specifically designed for mobile devices, where most applications only need a resolution of 38,000 pixels. The previous 100,000-pixel matrix was accordingly scaled down, and other functional blocks, such as the analogue/digital converter, have been optimised for chip area and performance range. System costs are lower: the sensor chip area is almost