NYT Article

Nobel Awarded for Advances in Harnessing Light

Their idea, originally intended for electronic memory, takes advantage of the photoelectric effect, which was explained by Albert Einstein and won him the Nobel in 1921. When light hits a piece of silicon, it knocks out electrons. The brighter the light, the more electrons are knocked out.

In a CCD, the knocked-out electrons are gathered in small wells, where they are counted — essentially one pixel of an image. The data from an array of CCDs can then be reconstructed as an image. A 10-megapixel camera contains 10 million CCDs.