US Patent 7864421 Symmetrical projection screen

Disclosed herein is a symmetrical projection screen. The screen includes a front screen member and a rear screen member. The front and rear screen members are made of a hard material, such as metal, or a hard film. Between the front and rear screen members is disposed a shock-absorbing member. The shock-absorbing member is made of a soft film having physical properties and material quality different from those of the front and rear screen members, such as compressed sponge, plastic foam, or poly vinyl chloride (PVC). The front screen member and the rear screen member are arranged in a front-and-rear symmetrical structure about the shock-absorbing member. Consequently, the deformation factors, such as external pressure or the change in the weather, are extinguished or cut off by the shock-absorbing member, whereby the flatness of the screen is maintained.