Welcome aboard, jhgjmhgvjhg. That is a truly marvelous idea indeed!
What we do here is to try and help people build an environment/world according to the requirements and restrictions of the situation.
Your idea looks very suitable for short distance (up to Jupiter or at most, Saturn) communication. However, I am afraid that the idea would fail for long distance communication.
The reason is that sun is a very, very, very big object. In fact if you were standing on a planet of our nearest star (Proxima Centauri) and looked toward our sun while Jupiter was passing in front of the sun, you would not easily see Jupiter. That is because the sun is so large and Jupiter (at such far distance from the sun) so small that you would not see any difference whether Jupiter was passing in front of the sun or not. You could see Jupiter if and only if you had some really, really powerful telescope with you.
Now think how much difference would a little piece of glass make and how difficult it would be to notice the shadow cast by it. No, it would not work at all even if the shade glass was the size of a continent!