What are 3-D Image Sensors?

3-D image sensors from Infineon are perfect for use in mobile consumer devices. These new REAL3 image sensors measure the time-of-flight of infrared signals, enabling sensing gestures the user makes in front of the screen. Infineon has designed the sensors with a perfect combination of power consumption, performance, functionality, cost, and size. The IRS238xC 3-D image sensors work in any kind of ambient light conditions and this makes them indispensable for reliable use in mobile applications.

The IRS238xC has high-performance pixel arrays that are highly sensitive to infrared light of 850 and 940 nm wavelength. This allows the device to perform unparalleled in any outdoor environment. Combined with this, Infineon has provided its patented SBI or suppression of background illumination circuitry in every pixel. The combination extends the nominal dynamic range of each pixel by nearly 20 times.

As the single-chip design has a high integration level, it allows the user to optimize the bill of material. Apart from this, it also reduces the design complexity and offers a small form factor. There are other advanced features as well, such as integrated high-performance ADCs, illumination control logic, a modulation unit with high flexibility, and circuitry for eye-safety that enables it to work as a laser-class-1 device. Interfacing is through a high-speed CSI-2 data interface.

The IRS238xC operates from an optimized in-built voltage supply unit, and it can self-boot as it has a full SPI master memory interface. Among the new features available on the sensor are, coded modulation and enhanced configuration flexibility. This allows the device to perform flexibly and robustly in multi-camera scenarios and similar use-cases.

The time of flight technology from Infineon works with stability, as high assembly yields prove, and this is a great boon for camera module manufacturers, as the IRS238xC not only simplifies calibration efforts, it also simplifies the camera module design. In short, IRS238xC combines the benefits of reliability, cost, size, functionality, and power consumption, making it indispensable for mobile 3-D sensing applications in all kinds of ambient light conditions.

For instance, the IRS238xC has the smallest module size giving 224 x 172 pixels, each of size 14 µm and with their own individual micro-lens. The suppression of background illumination or SBI provides each pixel with a 20-time gain in dynamic expansion against strong sunlight, but at minimum power consumption. The robust high-volume assembly of the device and its low calibration efforts offer an easy design and low system bill of materials for the designer.

IRS238xC offers time-of-flight technology for directly measuring the amplitude and depth of information in every pixel. It does this using a single modulated infrared light source that the chip emits to the whole scenery. The TOF imager captures the reflected light. The unit measures the phase difference between the emitted and the reflected light along with their amplitude values, thereby calculating the distance information and producing a grayscale picture of the entire scene all in one sweep.

Infineon provides algorithms that feature unique multiple benefits compared to other depth sensing technologies such as stereovision or structured light.