Module Or Discrete?

Jan. 19, 2006

Beyond the basic image sensor, manufacturers of imaging chips often provide value-added solutions in the form of complete camera modules (see the figure). These modules contain the imaging chip, a fixed- or adjustable-focus lens, and sometimes additional image processing, flash control, and auto-focus circuitry. Camera modules also come from independent companies that specialize in the low-cost assembly and manufacturing of products for the mass market.

These modules present a challenge because the most critical specification after price tends to be size. All three dimensions must be as small as possible so placing the module inside the cell phone doesn't cause an increase in the cell phone's size.

Fixed-focus lenses offer the lowest cost and most compact solution, but they don't deliver the sharpest image. Other focus schemes include the use of a voice-coil-based electromagnetic system or a piezoelectric scheme, since the focus adjustment distance is a small fraction of a millimeter. A more novel approach emerging from research labs uses a liquid-based lens that can be focused using a form of electrostatic deflection, eliminating all moving parts. Such liquid lenses promise better reliability while further shrinking the height of the lens assembly.

About the Author

Dave Bursky | Technologist

Dave Bursky, the founder of New Ideas in Communications, a publication website featuring the blog column Chipnastics – the Art and Science of Chip Design. He is also president of PRN Engineering, a technical writing and market consulting company. Prior to these organizations, he spent about a dozen years as a contributing editor to Chip Design magazine. Concurrent with Chip Design, he was also the technical editorial manager at Maxim Integrated Products, and prior to Maxim, Dave spent over 35 years working as an engineer for the U.S. Army Electronics Command and an editor with Electronic Design Magazine.