Panasonic ZS1 has a 10.0MP 1/2.5-inch (5.744 x 4.308 mm ) sized CCD sensor . On the other hand, Ricoh CX2 has a 9.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor and features Smooth Imaging Engine IV processor.
Below you can see the ZS1 and CX2 sensor size comparison.
As seen above, Ricoh CX2 has a 1.1x Larger sensor area than Panasonic ZS1. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.