Sony RX1R has a 24.0MP Full frame (35.8 x 23.9 mm ) sized CMOS sensor . On the other hand, Panasonic ZS100 has a 20.0MP 1" (13.2 x 8.8 mm ) sized MOS sensor and features Venus Engine processor.
Another difference between these two cameras is that Sony RX1R's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the RX1R and ZS100 sensor size comparison.
As seen above, Sony RX1R has a 7.4x Larger sensor area than Panasonic ZS100. 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.