If the display on your Philips Wake-up Light is not functioning properly, please check the following:
The display on my Wake-up Light does not function
Display setting might be too low
Turn on the lamp to a high setting, this will increase the display brightness or make the environment less bright. Increase the display brightness in the (SET) menu.
Direct sunlight
Direct bright sunlight shining on the Wake-up Light will blind the display. Remove it from direct sunlight.