Image sensors that can capture high-resolution images even in dark conditions are critically important elements of automotive cameras, which must be able to quickly and accurately sense and identify people or other obstructions in the images they take. With conventional image sensors for automotive cameras, under 0.005 lux light conditions that are equivalent to the dark of night, there had always been a marked drop in sensitivity, leading to darker image capture as well as difficulties in discerning one color from another.
Sony's newly commercialized CMOS image sensor has realized 2,350 mV (standard F5.6), a level of sensitivity that is around twice*4 that of conventional models and the industry's highest. This was achieved through the adoption of photo diodes that improve the conversion efficiency of light into electrons and through the installation of circuits that improve the conversion efficiency of those electrons into voltage. In addition, a programmable gain amplifier capable of amplifying electric signals up to 72 dB was installed in the sensor, further contributing to the ultimate achievement of a minimum object illuminance of 0.005 lux. Thanks to this innovative design, it now becomes possible to capture high-resolution color images even on a dark road at night with no stars to illuminate the surroundings.
This image sensor also supports a WDR (Wide Range Dynamic) system that allows for extended exposure time, which, when compared to conventional multi-exposure WDR systems, makes possible improved image quality in low light conditions when combined with a compatible ISP (Image Signal Processor)*5. Furthermore, the sensor also boasts a pixel structure with improved sensitivity to near infrared light outside the visual spectrum, an innovation that results in greater object recognition accuracy when the sensor is used in concert with a near infrared irradiating LED.
Sony has engaged in the technological development of image sensors for products such as professional and consumer-use cameras and smartphones with the central aim of creating high-resolution image capture technology. Going forward, however, Sony intends to expand its reach beyond the realm of digital imaging devices and into the arena of "sensing" as well. Building off products such as the "IMX224MQV," Sony will pioneer and tap into a new market for image sensors that are capable of acquiring and discerning information from captured images such as objects' distance, movement, shape, and color, for use in vehicles and elsewhere.
*4: When compared against Sony's "IMX238LQJ" CMOS image sensor with same pixel size (3.75μm).
*5: Mass production of compatible ISP from Sony is planned on June 2016.