Viewing angle control system and image display device

Abstract

A viewing angle control system is used in combination with a high-definition image display device and sufficiently shields light emitted in a direction oblique to a normal direction of a film. The viewing angle control system includes at least a first polarizer, a retardation layer, and a second polarizer in this order, where an absorption axis of the first polarizer forms an angle of 45° or greater with respect to a surface, the retardation layer satisfies Expression (1): an in-plane retardation Re of the retardation layer satisfies an expression of 80 nm<Re<250 nm, and Expression (2): in a case of Nz=Rth/Re+0.5, an expression of 1.5<Nz<6 or −5<Nz<−0.5 is satisfied, where Rth represents a retardation of the retardation layer in a thickness direction, and the second polarizer has an absorption axis in an in-plane direction.

Dependencies are inferred from the claim text.