Sony to Roll Out 8-Mpixel Automotive CMOS Sensor in 2020
Sony will start volume production of an automotive CMOS image sensor with a pixel count of about eight million in 2020.
The sensor will be used for forward-monitoring cameras to realize functions such as automatic braking and autonomous driving.
The pixel counts of existing automotive CMOS image sensors including products of companies other than Sony are about two million. By increasing pixel count, Sony aims to improve the range and accuracy of object recognition.
Sony started to ship samples of the sensor in 2017, planning to start volume production in June 2018 at first. The schedule was delayed due to specification changes, additional functions and market trends, but the company finally decided when to start volume production.
In regard to 8-Mpixel-class automotive CMOS image sensors, On Semiconductor Corp is planning to start volume production in the early 2020s.
Vehicles, while lines located 500m away can be recognized
There are two purposes in increasing pixel count. The first purpose is to make it easy to recognize objects located farther away. When an automotive CMOS image sensor with a pixel count of eight million is combined with a lens having an FOV (field of view) of 30°, it becomes possible to detect the types of vehicles and the states of white lines located 500m away, Sony said. It means that it is possible to take clear images of traffic signs located about 160m away.
With existing products having a pixel count of about two million, it is not possible to read the speed limit of a traffic sign located 100m or farther away.
The second purpose is to take images with wider angles. Automakers are rushing to develop measures to prevent left-turn (in Japan) collision accidents at intersections in urban areas. The new sensor will be used to prepare against pedestrians and bicycles entering an intersection from the blind spots of the user’s vehicle. Especially, bicycles cut across the front of a vehicle at a high speed, and shooting with a wider angle is required.
With an insufficient pixel count, the wider the angle, the smaller the number of pixels per 1°, blurring images. When the new sensor is combined with a lens having an FOV of 120%deg;, it becomes possible to detect vehicles and white lines located 137m away.
The pixel count of the automotive CMOS sensor that Sony decided to mass produce is about 7.42 million (3,849 (horizontal) x 1,929 (vertical)). Its size and pixel size are 1/1.7 inch and 2.25μm, respectively. Sony Semiconductor Solutions Corp, a subsidiary of Sony, is responsible for the development and production of the sensor. The dynamic range of the sensor is as high as 120dB.
One of the problems in increasing pixel count is that the load of processing shot video increases. As a result, automakers are required to employ image processing chips supporting 8-Mpixel-class CMOS sensors. Israel-based Mobileye and the US-based Nvidia Corp have a potential to supply such chips.
To have the new sensor combined with their products, Sony offers two models of the 8-Mpixel-class CMOS sensor to be mass-produced in 2020. One is “IMX324” and targeted at Mobileye’s image processing chips. Sony expects that the IMX324 will be combined with the “EyeQ5” next-generation chip, which Mobileye will start to mass-produce in 2021.
The other is “IMX424,” and Sony targets it at image processing chips of many companies (especially Nvidia). It will probably be connected mainly to Nvidia’s “Xavier” latest SoC (system on chip). The Xavier has already been employed by Toyota Motor Corp and Sweden-based Volvo Cars AG. It will probably start to be mounted on mass-produce cars in about 2020.
8 cameras connected to Nvidia’s automotive AI computer
To have the sensor widely employed, Sony exhibited it at GPU Technology Conference (GTC) 2019, which took place from March 17 to 21, 2019, in San Jose, the US. In a demonstration, Sony connected eight cameras to Nvidia’s “Drive AGX Xavier” automotive AI computer and showed that it is possible to monitor a 360-degree view around the vehicle. Four of the eight cameras were the IMX424, and the remaining four were “IMX390” with a pixel count of about 2.45 million (2,017 x 1,217).
The difference between the IMX324 and IMX424 lies in the color filter of CMOS sensor. The IMX324 uses an “RCCC” filter consisting of R (red) and C (colorless) filters. Mobileye has long been using RCCC filters. The red filter was employed to improve the recognition rate of objects indispensable for safety such as red lights and traffic signs.
On the other hand, the IMX424 comes with an “RCCB” filter using a B (blue) filter in addition to R and C filters.