[randomname93857]

To provide full Sun shade, the shield should be at L1. and it should have the same angular size from Earth as the angular size of the Sun

[Intralexical]

> and it should have the same angular size from Earth as the angular size of the Sun.

Technically you need a bit more than that, for its umbra to block out the entire photosphere over the entire Earth:

https://en.wikipedia.org/wiki/Tangent_lines_to_circles#Outer...