I started buying some very cheap white LED lights (3 lights for four dollars) and got a translucent white folder.
In this picture you can see two of the lights and the folder.
I also used an old biscuits can and a shoe box.
The diameter of the biscuit can is slightly higher than the outside diameter of the tube of my telescope, so it fits like a cap.
I cut out the bottom of the can, I made a hole of the same size in the cover of the shoe box and I set them together using duct tape.
I lined the interior of the box cover with the translucent white folder (taped) and the rest of the box with white paper (because it was dark gray).
This photo shows the can stuck in the box.
And in this one the can is opened and you can see the white translucent sheet through the hole in the bottom of the can.
I disassemble the lights and put the PCBs with the LEDs inside the box, I connected them with long cables to the battery base of one of the lights (the black disk seen in the photo).
I also put a switch to turn it on and off.
In this picture you can see the box open with the lights on.
When closed the light is reflected by the white bottom and walls and illuminates the white translucent sheet covering the top.
In front of each light I placed a piece of folded cardboard to avoid direct light to the the screen, which would make the lighting uneven. This can be seen in this photo.
Here you can see the light box placed on the telescope.
The duct tape you see is the box closure system.