Patent ID: 7324280

Claim:
A polarization pattern assembly for use in an illuminator having a pupil, comprising: (a) a frame; and (b) at least one polarization pane coupled to said frame, each polarization pane changing a direction of polarization of light passing therethrough, wherein said at least one polarization pane comprises first and second polarization panes made of birefringent material arranged in respective first and second layers of a stack, and wherein said first and second polarization panes are arranged to overlap each other; and (c) first and second pairs of non-polarization panes made of non-birefringent material, said first pair provided in the first layer on opposite sides of said first polarization pane and said second pair provided in the second layer on opposite sides of said second polarization pane, whereby at least one polarization pattern is obtained across the pupil of the illuminator.