Here is another article discussing research that shows that the electronic devices that you use in your bed can disrupt your sleep. Even though the screen is not very bright, it still disrupts secretion of melatonin, the hormone normally released to let your brain know it's time to sleep. Also, the devices tend to be stimulating and may increase alertness, rather than allowing you to relax and get sleepy. Finally, the devices strengthen the association of being awake in your bed. This by itself can fuel insomnia. You should only use your bed for sleep only.
Don't use these devices in your bed. You can use them on the couch in the living room - just get a blue light filter or use a blue light blocking program like f.lux.