From Astronomy.com.
The telescope can detect even the faintest of these winks, registering changes in brightness of only 20 parts per million. To achieve this resolution, Kepler will use the largest camera ever launched into space, a 95-megapixel array of charged couple devices, known as CCDs.
Here's the whole article:
http://www.astronomy.com/asy/default.aspx?c=a&id=7947