Radiation sensor

A combined proximity and ambient light sensor comprising:

• a radiation source;
• first and second pixels;
• a radiation absorption filter positioned over the first pixel but not the second pixel, wherein a combined spectral response of the radiation absorption filter and the first pixel has a first pixel pass-band and a first pixel stop-band;
• and
• an interference filter positioned over both the first and second pixels, wherein the interference filter has a first interference filter pass-band substantially within the first pixel pass-band and a second interference filter pass-band substantially within the first pixel stop-band.

A method of detecting ambient radiation comprising:

• a) filtering ambient radiation with a combination of a radiation absorption filter and an interference filter and detecting the filtered ambient radiation at a first pixel;
• b) filtering ambient radiation with the interference filter and detecting the filtered ambient radiation at the second pixel;
• c) reading a first signal from the first pixel;
• d) reading a second signal from the second pixel;
• and
• e) subtracting the first signal from the second signal.