Sony fits a digital video link into a 1 mm endoscope sensor
Image: Sony Semiconductor Solutions
Sony’s IMX742 sends digital video along a 5 m cable from a sensor measuring just 1 mm square. It combines a 720 × 720 pixel array with onboard conversion and a bidirectional link carrying video and control signals through the same cable.
The achievement is in fitting those functions together. Integrating the analogue conversion circuitry consumes silicon that could otherwise accommodate pixels, yet moving conversion onto the sensor avoids sending the small analogue image signal along the length of the instrument. Sony says it has reduced the peripheral circuitry sufficiently to retain approximately 0.51 effective megapixels and keep the connection to six pins.
Its published comparison images show less grain and fewer vertical artefacts than conventional analogue output. Sony attributes that improvement to digitising the signal at the sensor, particularly under the limited illumination available from LEDs inside a narrow endoscope. The company demonstrated the 5 m connection using AWG44 cable in its own evaluation setup.
The sensor supports 30 or 60 fps and uses 1 µm pixels with a Bayer colour filter. Its specification includes rolling shutter and global reset, with supply rails of 2.7 V, 1.2 V and −1.2 V.
Bronchoscopes and ureteroscopes are among the intended applications. The optics and illumination still have to fit around the chip, but Sony has brought the image acquisition, conversion and communication functions into a six-pin package. Samples are planned for November.
