An ambient light detector, a detector array and a method are disclosed. In an embodiment an ambient light sensor includes a first plurality of sensor elements, each sensor element configured to provide a signal in response to a level of illumination and a second plurality of reference elements, each reference element configured to provide a reference signal and each including a blocking element configured to shield the respective reference element from being illuminated, wherein the first plurality is larger than the second plurality and the first plurality of sensor elements and the second plurality of reference elements are arranged in an array, and wherein a sensor element and a reference element are laterally arranged on or in a common layer substrate sharing at least one common first contact.