摘要 |
<p>An assembly for restricting the angle of vision of an image emitted from an LCD screen (10) comprising a linearly parallel arrangement of two polarizing films (22, 24) with at least two waveplates (30, 32) therebetween. The transmission planes of the polarizing films are at an angle, preferably 90° to each other. At least two parallel waveplates are positioned between the polarizing films. Each waveplate has parallel transmitting regions alternating between birefringent (36) and isotropic regions (34). The waveplates are positioned in a spaced apart relationship to each other such that substantially orthogonal light passing through the first polarizing screen and one of the birefringent or isotropic alternating transmitting regions of the first waveplate will pass through the other of the alternating striped transmitting regions of the second waveplate. Light so transmitted will then pass through the second polarizing film and be viewable. At least a portion of the horizontal components of non-orthogonal light incident on the waveplate assembly will not pass through the second polarizing film. This assembly results in an angle of vision narrower than from the LCD screen.</p> |