Reading for owls
Once, an interesting task arose before me - to make a highlight for an e-book. Well, in general, this was a side quest to restore the buttons on it, but this upgrade seriously carried me away.
As usual, I climbed into Google in order to find out how people solved this problem so as not to reinvent the wheel. There were not so many solutions: either a finished book or a flashlight - a clothespin. The second, of course, was easier to implement, but somehow uninteresting. He sat, thought, and decided that it was necessary to peek at the displays on the LCD matrices.
Selection of components
We have one box on the shelf with all sorts of tablets and remotes. And, although the boss has long ordered to throw out idle devices from sin, we know the true value. A lot of useful detail there. This time I needed a display from an eight-inch tablet. More precisely, its optical plate, which makes our idea feasible. There is also a backlight, a current driver from another device - the remote control, because it was easier to cut from his board and the battery was more powerful.
Having played with the plate, it became clear that it is arranged in such a way that the light from the end extends to one face, which in the tablet was facing the user. So, you need to deploy so that it throws light on the screen of the book, and he, reflected, went into the eye.
The plastic was cut by side cutters to six inches, by the way, it is quite fragile and the first time I broke it. Well, then, blind, connect, solder everything.
As a result, a rather powerful flashlight turned out. But in general, the concept works, you can, of course, tighten the adjustment, somehow to the “feedback” leg on the driver chip, but this is a trifle.
Thank you all for your attention and good luck!