Until quite recently, although CMOS image sensors enjoyed the advantage of comparatively low power consumption, their structural weak point was a high level of noise, making them unsuitable for use in high-quality digital cameras. For this reason they were almost solely used in such devices as mobile phones. Although we knew that it would be possible to increase image quality by utilizing a back-illuminated structure to capture light more efficiently, the stumbling block we faced was an increase in noise. Consequently, most image sensor specialists believed that it was almost impossible to develop an image sensor based on such a structure.
In 2002, when I transferred from my previous job developing MOS logic and was assigned to the project team for image sensor development -- an area outside my direct expertise -- this was still the prevailing view among image sensor design engineers. When we began the project to develop an "Exmor R" back-illuminated CMOS image sensor, there were fewer than 10 of us on the project team. While we believed that our success could usher in a major change in the world of imaging technology, we spent a considerable period struggling to overcome the noise issue.
However, through ongoing trial and error, we came up with an idea that we thought might be the solution. Straight away, we asked the opinion of a Sony Handycam® video camera developer, who was startled by the exquisite image quality we showed him. The high quality of the images we shot, even in dimly lit settings, was unprecedented at the time. We received a directive to rapidly commercialize the technology and, as soon as we overcame issues relating to mass production, succeeded in commercializing the world's first consumer-use products to incorporate "Exmor R" back-illuminated CMOS image sensor technology.
Even during the period in which we struggled to overcome technical difficulties, the "Sony Spirit" kept us determined not to give in but to rise to the challenge, in the end leading to the creation of new technology. Even now, Sony's "Exmor R" back-illuminated CMOS image sensors have a clear competitive advantage. There is still ample room to improve the image quality and performance of image sensor technology, so we will not be resting on our laurels. We are committed to continuing our development efforts so that we can realize further advances in technology that will bring enjoyment and excitement to our customers.