Sony has developed a miniature single chip megapixel sensor that for the first time can capture images in both visible and short wave infrared (SWIR) at the same time.
The sensor uses Sony’s SenSWIR technology with a 5μm pixel, the industry’s smallest, for industrial applications. This uses photodiodes formed on an indium gallium arsenide (InGaAs) compound semiconductor layer and connected via a copper-to-copper connection with the silicon layer rather than a solder bump. Using this for the readout circuit enables high-sensitivity over a broad range of wavelengths from 0.4μm to 1.7μm as well as the smaller pixel size and a digital output.
Sony has used the technology in two compact sensors for cameras and test equipment for a wide range of industrial equipment such as such as material selection, contaminant inspection, and semiconductor inspection. The combination of visible and SWIR imaging allows a wider range of materials to be detected from a single sensor rather than multiple units with up to four times the resolution of previous SWIR sensors. This reduces the system cost and provides faster detection speeds thanks to the reduced image processing load, allowing for a dramatic expansion in testing range.
The first sensor, the IMX990, is a 1/2-type (8.2 mm diagonal) global shutter design with a 1.34 effective megapixel SWIR image sensor. It is packaged in a ceramic LGA package and ceramic PGA package with built-in thermoelectric cooling device. An 8 bit output provides a 130 frame/s output, falling to 70 frame/s with a 12 resolution. The power rails are 2.2 V, 1.2 V (pixel); 3.3 V, 2.2 V (analog); 1.2 V (digital); 1.8 V (interface).
The IMX991 is a 1/4-type (4.1 mm diagonal) with a 0.34 effective megapixel SWIR sensor in the same packages with the same power rails and outputs.