How to illuminate the display of the PR-15 remote control for Portos PPKR-311 roller shutters?

I have electrically controlled roller shutters throughout the house with switches like Portos PPKR-311 (now also Yooda DC 109 or Shakki DC 109). I have PR-15 remote controls to control them. The problem is that the remote control displays have no backlighting.
So, when all the blinds are closed and it's dark, there's no way to set the right channel to open the blinds, and pressing randomly can open a blind in, say, a bedroom where someone else is sleeping, or all the blinds in the whole house.
I would like to "retrofit" the illumination in the remote control. I would like to incorporate a small LED so that it lights up the display when the channel number is displayed. What is the smallest diode to use and how to connect it.
I know - the easiest way would be to buy a remote control that has a backlight. Unfortunately, my internet searches yielded nothing.
PS. The remote works in the 433.92 MHz band.

Hello
The choice of diode size, depends on the amount of space near the display. You would need to check this and then choose the right one. For sure it will be some smd LED https://www.google.pl/search?q=led+smd&bi...p;ved=0ahUKEwi1s-fE2_bQAhXCIcAKHSmCCr8QsAQISQ
The remote control has a 3V supply, it's the white colour for the diode, rather off. Check how much space there is then you can look for it. Of course, the diode cannot light up all the time, because the battery would wear out quickly. That is why you need an additional micro switch to switch on the LED https://www.google.pl/search?q=led+smd&bi...IcAKHSmCCr8QsAQISQ#tbm=isch&q=microswitch
So you will need an LED, a resistor and a microswitch.
Regards

Thank you.
I was thinking of taking advantage of the fact that the remote control display only works for about 3 secs after selecting a channel number and function and shuts off? There is probably some sort of timer circuit to switch on the power. I was thinking that since power is applied to the display automatically and it switches itself off, the diode could be wired to the same power supply? The display is liquid crystal. However, I am afraid that the power goes sequentially to the individual components and such a concept is rather out of the question.
Regards