I was surprised to hear that Hitachi Ltd is the originator of CMOS sensors because, as you know, the Hitachi Group does not make any CMOS sensors. Though I do not discuss the meaning of "originator" here, it is true that Hitachi developed the semiconductor that clearly resulted in today's CMOS sensors.

To be exact, what Hitachi developed was a MOS sensor. This is not the same MOS sensor that Panasonic Corp is currently manufacturing for lens-interchangeable cameras. Hitachi's MOS sensor did not have an output amplifier in each pixel. Because of its lower price and smaller size than image pickup tubes and CCDs, Hitachi's MOS sensor dominated the market until the first half of the 1980s despite its low image quality.

However, it could never overcome its weaknesses. In the second half of the 1980s, Sony Corp and Panasonic, among others, expanded their volume production of CCDs and kicked MOS sensors out of the market in no time. Hitachi withdrew from the image sensor business, and the time of CCDs arrived.

A change occurred at an unexpected point, however. In the 1990s, JPL (NASA Jet Propulsion Laboratory, currently belonging to the California Institute of Technology) of the US solved the noise problem by amplifying signals before noise occurs using a transistor in each pixel. Such image sensors are called active pixel sensors (APSs).

What even experts of image sensors often argue about is the question whether JPL is actually the originator of CMOS sensors. Current CMOS sensors, including Panasonic's MOS sensors, are all APSs. Considering this fact, it might be able to say that JPL is the originator. But when I had a small chat about this issue with a Japanese person, we reached a conclusion that "It's Hitachi." After all, it was just idle talk.

However, such ambiguity is not allowed in patent lawsuits. The California Institute of Technology (Caltech), which now owns JPL's patents, filed patent infringement lawsuits against Olympus Corp, Canon Inc, Samsung Electronics Co Ltd, Sony, Panasonic and Nikon Corp in October 2008, claiming that it owns the patents for quite fundamental technologies. No one knows which side the court's ruling will be in favor of, but it will significantly influence the dispute over the originator in any case.

Which is the originator, Hitachi or JPL? Or is it another company or institution? If any of you know the relevant history, please enlighten me with your knowledge. I myself will research it between articles and report on the results.