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LBCAST

In July 2003, Nikon introduced LBCAST- a completely new type of image sensor, different from CCD and CMOS, that is a high-speed, power-efficient, low-noise device to be installed in Nikon's flagship camera, the D2H. Here is the inside story behind the creation of this innovation, from those who conceived and developed it.

ISOGAI, Tadao
Photonics Technology Group
Core Technology Center
Nikon Corporation

His favorite camera is the Nikon FE. "I use a film camera, but my child uses COOLPIX and I borrow it sometimes. I feel digital cameras are convenient to use."

SUZUKI, Satoshi
Photonics Technology Group
Core Technology Center
Nikon Corporation

His hobbies are tennis, swimming and running. "Running enhances my concentration. It is also good for relaxing my mind. So I ran a lot during the development of LBCAST." These days, he is also devoted to cultivation of herbs, which he routinely enjoys.

Nikon's original LBCAST image sensor is superior to conventional sensors in its speed, power efficiency and low noise.

The LBCAST image sensor was introduced in July 2003. First, please explain what it is.

Isogai, Tadao (I,T):

The LBCAST image sensor comes from a totally new concept developed exclusively by Nikon, combining the advantages of conventional CCD (Charge-Coupled Devices) and CMOS (Complementary Metal-Oxide Semiconductor) technology.

Does that mean that the LBCAST device replaces a conventional CCD as an image processor?

I,T: Exactly. The first LBCAST-equipped model is one of our flagship models, the D2H.

LBCAST is installed in the Nikon D2H, one of the company's flagship models, for the first time.

In what technological aspect is LBCAST decisively superior?

I,T: Compared with conventional sensors, it saves more power and achieves less dark noise (a phenomenon in which randomly-spaced bright pixels appear in images due to the heat from the image device during shooting). Also, LBCAST increases image processing speed and improves sensitivity, contrast and color reproduction.

Up to now, CCD or CMOS have usually been installed in digital cameras as image devices. Isn't LBCAST a new kind of image sensor that replaces CCD or CMOS?

I,T: Yes. When we compared CCD and CMOS, CCD generated less noise in general, while CMOS was superior in power efficiency and startup speed. But the LBCAST concept is totally different from that of these two devices, and combines advantages of both devices, with its low noise, high power-saving and high-speed characteristics.

It took first 10 years of LBCAST development for us to find our way.
We were enthusiastically supported to create a device that surpassed the CCD.

Mr. Isogai and Mr. Suzuki, have you both been developing this device for a long time?

I,T: Yes, I have been involved in the development and trial production of devices since I joined the Company, and for much of that time, I have been seriously involved in image sensor development.

SUZUKI, Satoshi (S,S):

I have also devoted myself to developing image sensors since I joined the Company. I was really lucky that trial production of the image sensor started soon after I joined the Company

I,T: We have a lot of collective experience studying image sensors. Looking back to that time, we spent a good many years preparing to develop LBCAST, seeking a foundation for further future development. Perhaps, at the time we started this study, few people in the company knew what we were doing. Our group's work attracted little attention.
But repeated trial and error shaped our goal toward new image sensor development. D2H will be the fruit of our efforts.

How did you come to work on development of Nikon's unique image sensor?

I,T: After long study, we became able to produce devices and gained confidence in our technologies. So we started to discuss what we should produce within Nikon, according to Nikon Imaging Company's strong desire to procure its own image devices. In those days, the cost of an image device was so high. It was actually more expensive than the price of a camera. It was obvious that the needs for image devices would increase in the future, so the need to deal with the problem of costs was clear and crucial to us.

But why didn't you think about new CCD development?

I,T: To be honest, Nikon was a late starter in CCD development, and it seemed difficult to overtake pioneers in the field and achieve remarkable progress. So from the start, we aimed to develop a new image device beyond the CCD, using a different developmental approach than was used for the CCD.

I see. So you maintain a passion to develop something superior to a CCD.

I,T: Yes. CCDs in those days were successfully mass produced, but studies of amplifying image sensors, from which the current CMOS originated, began to draw attention. So we wanted to develop amplifying image sensors *1 into actual products.

So LBCAST originated with CMOS?

I,T: No. When we started the study, only the concept of amplifying sensors existed, and there was no word of CMOS. So we recognized that we were studying amplifying sensors. We never paid attention to CMOS.

S,S: CMOS is used as a peripheral circuit for LBCAST, but this doesn't mean that LBCAST follows CMOS. We were just looking for what would bring out the most in the new LBCAST image device, and that was CMOS. CMOS was not essential for development of LBCAST.

At times, while running at my fitness club, I worked out plans in my mind for developing LBCAST.

I see. So you started from nothing.

I,T: Exactly. We started the study by looking for our way. Because our group is based on the research institute, we have the spirit to look for new things. So we were able to start development with free thinking, which was fortunate for the study. We didn't have any specific goals on specifications or features, but we just improved performance gradually through careful observation.

  • *1Amplifying sensor: This sensor amplifies signals through the transistor on each respective pixel and transfers the amplified signals into the image processing system via wire. This system is called the "X-Y address system."