A light receiver device, which is particularly suited for a smoke detector, has a flat substrate, a light receiver mounted on a front side of the substrate, and a shielding device present on at least a back side of the substrate opposite the front side. The shielding device is configured to at least partially shield against electromagnetic interference radiation impinging on the light receiver through the substrate. False alarms are thereby reduced, while the sensitivity of the light receiver is simultaneously increased. The shielding device is formed with a metal strip inserted through the substrate from the front side to the back side, and bent over a recess on the back side provided therefor, so that the light receiver is protected against interference radiation even on the back side. There is also provided an assembly method for producing a light receiver device.