I'd like to make a "magic mirror", something very similar to this https://blogs.windows.com/msedgedev/2016/05/31/magic-mirror-hosted-web-app/, but much smaller.
Basically, I have a closed box (no light can enter), with the electronic board inside, and a semi reflective mirror on the top (screen under the semi reflective mirror).
I am currently using an OLED display like this http://www.buydisplay.com/default/oled-display/2-4-inch because I thought it was the only solution to have black background, so that we only see the white characters which seem to float behind the mirror.
But, actually, I found out that there exist cheap lcd displays with a black background. I'm not sure to understand because I thought that lcd were working with a backlight, so that I can't understand how the background can be black (which is not light !).
If it exists, would you explain me how it works, and if I could obtain the same effect that white characters seem to float (no rectangular backlight under the mirror) ? That would be great because OLED screens are so expensive.