iPhone 5 will not stay on unless light hits the screen

[mcpupmac]

A few nights ago I discovered that my iPhone will not stay on when it is dark, or relatively dark. The screen comes on for a fraction of a second...more like a blink. Then I found that if I am outside in the daylight, or hold it under a light, it comes on and works fine. Anyone had this problem?

 

[leillox88]

Maybe a dimmer sensor? Do you have your brightness set manually or to dim automatically?