A mobile computing device includes an emissive display panel configured to emit light from a front surface of the display panel, with the display panel having a plurality of transparent layers and an opaque back cover layer. The mobile computing device also includes a light sensor located behind the opaque back cover layer, and the opaque back cover layer includes an opening through which light from outside the display that is transmitted through the transparent layers of the display can pass to reach the sensor. An air gap separates the light sensor from the transparent layers of the display panel. The plurality of transparent layers includes a reflection attenuating layer on a back side of the display panel configured to attenuate the reflection of light from an interface between a transparent layer of the display panel and the air gap.