Yes, the blue lights from tvs, Ipads, cellphones, etc, stop the brain from making melatonin. I've studied this subject til the cows came home and now I know how to improve my sleep. It's not easy!
I've been aware of this as well, and have been using a little program called f.lux for several years now. It dims the light on your computer (tablets & mobile phones) according to time of day allowing you to fall asleep just as you would while reading a book late at night. It's free for home use and does not contain any malware or computer viruses. Here is how the program developers describe it. .
f.lux is a cross-platform computer program that adjusts a display's color temperature according to location and time of day, offering functional respite for the eyes. The program is designed to reduce eye strain during night-time use, helping to reduce disruption of sleep patterns. Computer screens, tablets and mobile phones emit full spectrum light around the clock, just like the sun. Exposure to blue light at the wrong time of day can keep you awake later and interfere with the quality of your sleep. f.lux works by removing blue and green light to help you wind down in the evenings.
* formerly Zadok, who needed to go tend some apple trees over in Big Spruce