Apparatus for testing an array of light-sensitive electronic devices, the apparatus comprising: an array of LED, light emitting diode, light sources, wherein the array of LED light sources is configured to have a respective LED light source (102, 104, 106, 108) corresponding to each of the electronic devices (122, 124, 126, 128); wherein each LED light source (102, 104, 106, 108) includes a light emitting diode configured to provide LED light; wherein each LED light source (102, 104, 106, 108) includes a phosphor disposed to receive the LED light and to provide phosphorescence light; wherein each LED light source (102, 104, 106, 108) includes an aperture configured to provide point source illumination from the phosphorescence light; wherein each LED light source (102, 104, 106, 108) includes a lens configured to provide collimated light from the point source illumination; wherein each LED light source (102, 104, 106, 108) includes a uniformity filter disposed to receive the collimated light and to provide output light having improved uniformity of illumination; a feedback control system configured to measure optical signals from each LED light source (102, 104, 106, 108) and configured to control operation of the array of LED light sources (102, 104, 106, 108) using the measured optical signals to provide uniform illumination to the array of light-sensitive electronic devices(122, 124, 126, 128); wherein each LED light source further comprises a first photodetector and a second photodetector with a neutral density filter disposed on the second photodetector; wherein the optical signals are provided by both the first photodetector and the second photodetector. an array of LED, light emitting diode, light sources, wherein the array of LED light sources is configured to have a respective LED light source (102, 104, 106, 108) corresponding to each of the electronic devices (122, 124, 126, 128); wherein each LED light source (102, 104, 106, 108) includes a light emitting diode configured to provide LED light; wherein each LED light source (102, 104, 106, 108) includes a phosphor disposed to receive the LED light and to provide phosphorescence light; wherein each LED light source (102, 104, 106, 108) includes an aperture configured to provide point source illumination from the phosphorescence light; wherein each LED light source (102, 104, 106, 108) includes a lens configured to provide collimated light from the point source illumination; wherein each LED light source (102, 104, 106, 108) includes a uniformity filter disposed to receive the collimated light and to provide output light having improved uniformity of illumination; a feedback control system configured to measure optical signals from each LED light source (102, 104, 106, 108) and configured to control operation of the array of LED light sources (102, 104, 106, 108) using the measured optical signals to provide uniform illumination to the array of light-sensitive electronic devices(122, 124, 126, 128); wherein each LED light source further comprises a first photodetector and a second photodetector with a neutral density filter disposed on the second photodetector; wherein the optical signals are provided by both the first photodetector and the second photodetector.