Patent ID: 7220007
Filing Date: 2007-05-22
Classification: G03B

Abstract:
1. An outer suspension type lens shielding mask for a projection apparatus, comprising: a base plate, wherein a rectangular hole is opened therein; at least one upper adjustable plate and one lower adjustable plate, installed on said base plate, and two corresponding open type rectangular notches being respectively disposed in the middle of the lower end of said upper adjustable plate and the upper end of said lower adjustable plate; and at least one adjustment apparatus, constituted by a plurality of connecting elements connected to said plate and said upper and said lower adjustable plates for the relative positions of said upper and said lower adjustable plates to be adjusted on said base plate; wherein said connecting elements are sleeves and said sleeves are respectively disposed on the corners of said base plate and the left and the right side of said upper and said lower adjustable plates to form two arrays of sleeves and said all sleeves on said two arrays are aligned one another; and wherein screw threads are only disposed in one of said two arrays of aligned sleeves on the left and the right sides of the upper and the lower adjustable plates and said screw threads in the upper and the lower sleeves of said array are reverse, said adjustment apparatus is a bolt and a straight shaft without screw threads, said bolt is passed through said sleeves with screw threads and said straight shaft is passed through said sleeves without screw threads, and said screw threads on the upper and the lower sections of said bolt are reverse, said reverse screw threads are respectively matched up with said corresponding screw threads in said sleeves.