Display device having a diffusing display panel and a reflecting polarizer
First Claim
1. A display device comprising an illumination system having a radiation source for supplying a radiation beam, and a diffusing display panel comprising an optically active diffusing medium which is switchable between a transparent, polarization-maintaining state and a diffusing, depolarizing state for the radiation beam, a first polarizer having a first polarization effect and a second polarizer having a second, complementary polarization effect, said polarizers enclosing the medium, characterized in that at least said first polarizer is a reflecting polarizer and in that polarization-converting means are arranged at a side of said first polarizer facing away from the diffusing medium, said polarization converting means converting light reflected from said first polarizer to a state of polarization which is transmissible by said first polarizer;
- said optically active diffusing medium, in said polarization-maintaining state, being transparent to light in said state of polarization which is transmissible by said first polarizer.
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Accused Products
Abstract
Display device (1) comprising an illumination system (3) having a radiation source (17; 31, 35) for supplying a radiation beam. The display device (1) also comprises a diffusing display panel (5). This panel (5) consists of an optically active diffusing medium (7) which is switchable between a transparent, polarization-maintaining state and a diffusing, depolarizing state for the radiation beam. The medium (7) is present between a first polarizer (9) having a first state of polarization and a second polarizer (11) having a second, complementary state of polarization. At least the first polarizer (9) is a reflecting polarizer and polarization-converting means (10) are arranged at a side of the first polarizer (9) facing away from the display panel (5).
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Citations
13 Claims
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1. A display device comprising an illumination system having a radiation source for supplying a radiation beam, and a diffusing display panel comprising an optically active diffusing medium which is switchable between a transparent, polarization-maintaining state and a diffusing, depolarizing state for the radiation beam, a first polarizer having a first polarization effect and a second polarizer having a second, complementary polarization effect, said polarizers enclosing the medium, characterized in that at least said first polarizer is a reflecting polarizer and in that polarization-converting means are arranged at a side of said first polarizer facing away from the diffusing medium, said polarization converting means converting light reflected from said first polarizer to a state of polarization which is transmissible by said first polarizer;
- said optically active diffusing medium, in said polarization-maintaining state, being transparent to light in said state of polarization which is transmissible by said first polarizer.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A display device comprising
an illumination system having a radiation source for supplying a radiation beam, an optically active diffusing medium which is switchable between a transparent, polarization maintaining state and a diffusing, depolarizing state for the radiation beam, a first polarizer between said optically active diffusing medium and said radiation source, said first polarizer being a reflecting polarizer which transmits light having a state of polarization which is transmissible by said optically active diffusing medium when said medium is in said transparent, polarization-maintaining state, a polarizing reflector arranged oppositely of said radiation source from said first polarizer, said polarizing reflector converting light reflected from said first polarizer to a state of polarization which is transmissible by said first polarizer, and a second polarizer arranged oppositely of said diffusing medium from said first polarizer, said second polarizer blocking radiation having said state of polarization which is transmissible by said first polarizer.
Specification