Physics Photo of the Week

October 9, 2009

CCD Dectors - 2009 Nobel Prize in Physics
Astronomy, medical imaging, and ordinary photography have been revolutionized by the development of solid state imaging detectors called CCD arrays.  These devices were invented and developed in the late 1960's by Willard Boyle and George Smith at Bell Labs in the USA.  The proven technology in the past 40 years has earned Boyle and Smith half the 2009 Nobel Prize in Physics announced earlier this week. 

This photo shows a CCD detector (Charged Coupled Device) as part of an astronomical camera.  A highly magnified view of the detector is shown in the lower picture where we can barely see the indivual pixels of the detector.  Each tiny pixel is approximately 10 microns (0.01 mm) across.

CCD detectors have made the development of consumer digital cameras entirely possible.  They are also found in virtually all video cameras - even the cameras used for broadcast TV.  Of course all the photos featured in Physics Photo of the Week are taken with digital cameras fitted with these solid state arrays.  Digital photos naturally promote the use of photos through computer technology.

The main technological advantage to solid-state digital photography - besides compactness, low power consumption, non-expendable film, instant "developing" - are that the output signals are proportional to the amount of light striking the detector.  Traditional film is highly non-linear.  The linear output makes these detectors excellent where the light intensity needs to be measured.  Astronomy was the first discipline to widely adopt the use of these detectors for this reason.  Recent graduates Hannah Barks (2006) and George Keel (2008) used the camera featured here to perform excellent photometry on stars for their Natural Science Seminar projects.

CCD detectors consist of 2-dimensional arrays of phototransistors on a single chip of silicon called an Integrated Circuit.  (See PPOW for December 8, 2006 and November 18, 2005.  The Swedish Academy had previously recognized transistors and  integrated circuits for their significant contribution to technology:  The discovery of the transistor in 1948 by John Bardeen, Walter Brattain, and William Shockley earned them the 1956 Nobel Prize in Physics.  The development of integrated circuits - many transistors on a single chip of silicon - in the early 1960's by Jack St. Clair Killay - earned a portion of the 2000 Nobel Prize in Physics. 

Besides recognizing the ubiquitous technology responsible for digital imaging, the Nobel Committee awarded the other half of the 2009 Nobel Prize in physics to Charles Kao for the development of special optical fibers for communication.  Although we don't ordinarily see the optical fibers, they are responsible for the vast increase in internet speed as well as lower costs for long distance communication.

Thank yous are extended to Natasha Shipman of the Biology Department for lending a dissecting microscope through which the microscopic image of the chip using was photographed using a digital camera.




Physics Photo of the Week is published weekly during the academic year on Fridays by the Warren Wilson College Physics Department.  These photos feature interesting phenomena in the world around us.  Students, faculty, and others are invited to submit digital (or film) photographs for publication and explanation.  Atmospheric phenomena are especially welcome.  Please send any photos to dcollins@warren-wilson.edu. 

All photos and discussions are copyright by Donald Collins or by the person credited for the photo and/or discussion.  These photos and discussions may be used for private individual use or educational use.  Any commercial use without written permission of the photoprovider is forbidden.


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