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Willard Boyle and the CCD

May 23, 2011

Avid readers of this blog may recall that I once worked with magnetic bubble memories. What they may not know is that the electronic imaging devices in their cellphones and cameras were inspired by magnetic bubbles.

In 1969, Willard Boyle and George E. Smith of Bell Labs noticed their colleagues' work on magnetic bubbles devices which shuttle magnetic domains in a materials using magnetic fields. They devised an electrical analog of the magnetic devices in which electric charge was shuttled around by electric fields. Willard Boyle, who shared the 2009 Nobel Prize in Physics with Smith and Charles K. Kao, died in his home town of Wallace, Nova Scotia, Canada, on May 7, 2011, at age 86.[1-5]

Boyle and Smith's invention[6] was the charge-coupled device, commonly called a CCD. As shown in the figure, application of a voltage sequence at electrodes shuttles electric charge through the semiconductor material. One application of the CCD was as a serial memory device, an electrical analog to a bubble memory, but it's most important use was as an electronic imaging device. In the imaging application, there's an additional photoactive region that produces the charges. In CCD cameras, the image data are stepped out to the edge of the circuit chip by moving the charge created by the image.

Figure captionFigure caption
Figure captionFigure caption
Figure captionFunctional diagram of a basic CCD device. Positive voltages at the electrodes move charge through the semiconductor material.

Images by Michael Schmid, via Wikimedia Commons

CCD cameras revolutionized astronomy because of their high quantum efficiency and linearity. Cameras are not the only devices that were enabled by CCDs. They're used also in bar code readers, document scanners, copiers and fax machines. In its announcement of the 2009 Nobel Prize in Physics, the Nobel Foundation included the following statement in its press release.[7]
"The CCD ...revolutionized photography, as light could now be captured electronically instead of on film. CCD technology is also used in many medical applications, e.g. imaging the inside of the human body, both for diagnostics and for microsurgery. Digital photography has become an irreplaceable tool in many fields of research. The CCD has provided new possibilities to visualize the previously unseen. It has given us crystal clear images of distant places in our universe as well as the depths of the oceans."
The idea for the CCD came in 1969, in a post-lunch brainstorming session between Smith and Boyle in Boyle's office. Boyle said that the first model of the CCD idea worked after just an hour's effort.[2] Within a year they had demonstrated a digital camera based on the CCD idea. The device had such possibilities that Fairchild Semiconductor built a prototype 10,000 pixel CCD imager in 1973. 10,000 pixels is 0.1% the resolution of a typical home digital camera. The camera was in production at Fairchild in 1975, the same year that Smith and Boyle demonstrated a CCD video camera.

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Fig. 4 of US Patent No. 3,858,232, "Information Storage Devices," by Willard Sterling Boyle and George Elwood Smith. The CCD patent was just one of thirteen patents that listed Boyle as an inventor.

Boyle was Canadian, having been born on Aug. 19, 1924, near the village of Wallace, Nova Scotia. His parents moved to Chaudiere, Quebec, when he was three years old.[5] Since the nearest school was thirty miles away, Boyle was homeschooled by his mother.[1] Boyle's education was all Canadian. He attended secondary school in Montreal, and then McGill University, but his education was interrupted by World War II. Boyle left McGill in 1943 and became a Spitfire pilot in the Royal Canadian Navy. At war's end, he returned to McGill, eventually earning a Ph.D. in physics in 1950.

After receiving his Ph.D., Boyle worked for a year at the McGill University Radiation Laboratory, taught physics for two years at the Royal Military College of Canada (Kingston, Ontario), and then went to work at Bell Labs. Boyle spent the rest of his career there, retiring as Executive Director of Research in the Communication Science Division in 1979.

Innovative even before the CCD, Boyle worked with Don Nelson to demonstrate the first continuously lasing ruby laser in 1962, improving the pulsed ruby laser invented by Theodore Maiman in 1960. He collaborated with David Thomas on the semiconductor injection laser.[2] Boyle helped select the Apollo lunar landing sites.[1]

The CCD invention has made a lot of money for a lot of people. As a commentary on how society values science, the 2009 Nobel Prize in Physics was valued at $1.4 million. Boyle and Smith received half the monetary award, so Boyle's share was $350,000. This, in an era when the average annual compensation of the Fortune 500 CEOs was more than $5 million.

As told in the Toronto Sun, Boyle drove a Mini Cooper with the license plate, "CCD."[4] Boyle was appointed to the Order of Canada just last July. In 2005, he was inducted into the Canadian Science and Engineering Hall of Fame.[4]

References:

  1. By Thomas H. Maugh II, "Willard S. Boyle dies at 86; a father of the digital camera," Los Angeles Times, May 19, 2011
  2. Douglas Martin, "Willard S. Boyle, Father of Digital Eye, Dies at 86," The New York Times, May 9, 2011.
  3. T. Rees Shapiro, "Willard S. Boyle, Nobel Prize-winning physicist, dies at 86," Washington Post, May 9, 2011.
  4. Sheena Goodyear, "Canadian Nobel laureate dies," Toronto Sun, May 9, 2011.
  5. Nobel-winning physicist Willard Boyle dead at 86, CTV.ca News, May. 10, 2011.
  6. Willard Sterling Boyle and George Elwood Smith, "Information Storage Devices," US Patent No. 3,858,232, August 4, 1974.
  7. "The Nobel Prize in Physics 2009 - Charles K. Kao, Willard S. Boyle and George E. Smith," Nobel Prize Web Site.