Optics System for the Film Project in the Circle Vision Theatre of the Great Wall

The size of the circular screen installed in the circle vision theatre of the Great Wall, the calculation method of the screen's brightness and its even nature are presented in this paper. The projective lens of the film projector and the illuminating system of the theatre are analysed. It is shown, through the practical operation of this system that light interference is eliminated, and the degree of clearness is increased. the system on the whole is highly praised by the public.