Happy Birthday: CCD-Sensor

| |
1 Star2 Stars3 Stars4 Stars5 Stars

electronica is turning 50. Never have electronics inventions changed our lives as fundamentally as during these last fifty years. We will look at the most important developments in a small series of articles. This installment: The birth of the CCD-sensor.

On December 10, 2009, American researchers Willard S. Boyle and George E. Smith were awarded the Nobel prize for Physics in Stockholm. At the time, their invention—the CCD (charge-coupled device) sensor—was 39 years old, and the two scientists from Bell Laboratories were 85 and 79 years old. Their light-sensitive chip has since revolutionized photography as the “electronic eye” in digital cameras. Several other applications in medicine, aerospace and deep-sea research would also be unimaginable with the CCD.

From barcode readers to the Hubble Space Telescope

Their lab was actually working on data storage. The objective was to transport a charge along the surface of a semiconductor. “The actual invention took place during an afternoon discussion between us lasting only about one hour,” the two reported. Then it took “about a week” to come up with the first CCD prototype.

Even though CCD photo sensors now have more energy-efficient and more “sensitive” competition—many cellphone cameras now use CMOS sensors—the Bell researchers’ invention was a milestone on the road to the digital revolution.

Theory and practice

Incidentally, Albert Einstein received the Nobel Prize for his discovery of the law of the photoelectric effect in 1921, the theoretical basis of this invention, and not for the special theory of relativity. That law describes how light is converted into electric signals.

The that is exactly what the CCD photosensor does: It releases electrical charges that are created when light hits the chip’s light-sensitive photodiodes.

Scientists at Bell built the first solid-state camera with A CCD image sensor in 1970. It was still an analog video camera with “live image”. It was not yet possible to save individual images. The first commercial CCDs with a resolution of 0.01 megapixels were produced by Fairchild Imaging in 1973. The first “genuine” digital camera came out in 1975. However, the 4-kilogram prototype from Kodak needed more than 20 seconds to save an image on a digital cassette. The Fairchild MV-101, the first commercially available CCD camera, came out a year later.

CCD Bell Labs

Willard Boyle, left, and George Smith from Bell Labs with a television camera that contains a charge-coupled device, or CCD.