A second plane mirror and a third plane mirror that are placed in parallel and have opposite reflecting surfaces to ensure that the imaging light can be transmitted for a long distance in a limited space;
A second plane mirror and a third plane mirror which are placed in parallel and have opposite reflecting surfaces to ensure that the imaging light can be transmitted for a long distance in a confined space;
A second plane mirror and a third plane mirror, which are placed in parallel and have opposite reflection surfaces, to ensure that imaging light can be transmitted for a long distance in a limited space;