I've done that before and it didn't make any difference for me. If I read a book on a screen or on paper before bed, it doesn't seem to matter, as long as the light is 1850K.
How do you know when to go to bed when idling on a device? There is just endless streams of crud to browse, code to write or whatever. Do you need to have a "bed time" or you just end up feeling tired?
What I've noticed about eliminating (most) device use after 7pm is that I'm actually pretty excited to go to sleep around 9:30-10pm because I just end up feeling tired. When I was browsing, consuming social media etc, I just didn't really know when to stop.
Mindfulness helped me reining that in: I learned to listen to my bodily feelings instead of half-consciously shunting them because ooooh shiny compulsive refresh. It worked both ways: I realised sometimes I tried too hard going to bed when I wasn't tired enough (if at all) and I just slept a couple hours tops, then couldn't sleep for the remainder of the night, which just sucks when the end of the next day comes.
Along with practicing mindfulness, the biggest change for me was killing all blue light sources. This had the most dramatic effect of all things.
But the thing that really helps me is the feature in f.lux that is a reverse alarm clock. Starting at midnight, it pops up an alert saying "you're waking up in eight hours". It does that every 1/2 hour, counting down. So at least every 1/2 hour a get a reminder to at least think about going to bed.
I can honestly say it's been game changing for me to do this. I just read paper books now, taken a while to get into the habit but my sleep has improved so dramatically since then.
Also, my phone charger lives in the kitchen, so my phone doesn't come to bed with me, also a dramatic improvement.
What is strange about all this is that fluorescents, while not pleasant to use, don't seem to keep my up like devices do. In that I can have one on for 30 minutes before bed and sleep well. Maybe it's not the light but the stimulation that affects us?