Driving waveforms for switchable light-collimating layer including bistable electrophoretic fluid
AssigneeE Ink California, LLC
InventorsPubudu Thilanka Galwaduge, Xiaolong Zheng, Craig Lin
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Abstract
Methods and controllers for driving a light-collimating film including elongated chambers of bistable electrophoretic fluids. The light-collimating films are suitable to control the amount and/or direction of light incident to a transmissive substrate. Such films may be integrated into devices, such as LCD displays, to provide a zone of privacy for a user viewing the LCD display. Because the light-collimating film is switchable, it allows a user to alter the collimation of the emitted light on demand. Because the films are bistable, they do not require additional power after they have been switched to a display state.
Claims21
A method for driving a switchable light-collimating film,
- wherein the switchable light-collimating film includes:
- a first light-transmissive electrode layer,
- a collimating layer having a thickness of at least 20 μm, and comprising a plurality of elongated chambers, each elongated chamber having an opening,
- a bistable electrophoretic fluid comprising pigment particles disposed in each elongated chamber,
- a sealing layer that seals the bistable electrophoretic fluid within at least one of the plurality of elongated chambers by spanning the opening of the elongated chamber, and
- a second light-transmissive electrode layer, wherein the first and second light transmissive layers are disposed on either side of the collimating layer,
- the method comprising applying a time varying voltage between the first and the second light-transmissive electrode layers.
A display comprising:
- a light source;
- a switchable light-collimating film comprising:
- a first light-transmissive electrode layer,
- a collimating layer having a thickness of at least 20 μm, and comprising a plurality of elongated chambers, each elongated chamber having an opening,
- a bistable electrophoretic fluid comprising pigment particles disposed in each elongated chamber,
- a sealing layer that seals the bistable electrophoretic fluid within an elongated chamber by spanning the opening, and
- a second light-transmissive electrode layer, wherein the first and second light transmissive layers are disposed on either side of the collimating layer;
- an active matrix of thin film transistors;
- a liquid crystal layer;
- a color filter array;
- a voltage source;
- and
- a controller to provide a voltage impulse between the first and second light-transmissive electrode layers, wherein the voltage impulse causes a change in the effective transmission angle of the display.
Dependencies are inferred from the claim text.