Both Nikon AW110 and Ricoh WG-50 have 16.0 MP resolution sensors but Nikon AW110's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Ricoh WG-50's sensor is (1/2. ).
Since Nikon AW110's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Ricoh WG-50.
Below you can see the AW110 and WG-50 sensor size comparison.
As seen above, Nikon AW110 has a infx Larger sensor area than Ricoh WG-50. 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.