Method and apparatus for front-lit semi-retro-reflective display
AssigneeCLEARink Displays, Inc.
InventorLorne A. WHITEHEAD
Life of this patent
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Abstract
The disclosure generally relates to a front-lit display having transparent and selectively emissive light directionality. The disclosed semi-retro-reflective, semi-specular and specular displays include directional front light systems that reflect light in a manner to preserve the non-Lambertian characteristic of the light output. This leads to brighter displays with a higher degree of luminance as compared to conventional microencapsulated electrophoretic displays with substantially Lambertian reflectance where much of the light is not reflected back towards the viewer.
Claims25
A reflective display device, comprising:
- a semi-retro-reflective display sheet having one or more convex protrusions that reflects light in a narrow angle relative to the direction of the incident light;
- a light source to emit light in a perpendicular direction towards the display sheet;
- a front electrode;
- a rear electrode;
- a fluid disposed between the front and the rear electrodes;
- a plurality of electrophoretically mobile particles suspended in the optically transparent fluid;
- and
- a voltage source in communication to the front and the rear electrodes to selectively move the electrophoretically mobile particles in the fluid.
A reflective display, comprising:
- a transparent outer sheet;
- a light source to emit light in a perpendicular direction towards the transparent outer sheet;
- a rear electrode;
- a perforated sheet situated between the light source and the rear electrode;
- a front electrode disposed over the perforated sheet;
- a semi-retro-reflective surface over the perforated sheet;
- a medium disposed within the cavity formed between the transparent outer sheet and the rear electrode;
- a plurality of electrophoretically mobile particles suspended in the medium;
- and
- a voltage source in communication to the front and the rear electrodes to selectively move the electrophoretically mobile particles in the fluid.
A reflective display, comprising:
- a transparent outer sheet;
- a light source to emit light in a perpendicular direction towards the transparent outer sheet;
- a rear electrode;
- a perforated sheet situated between the light source and the rear electrode;
- a reflective layer disposed over the perforated sheet;
- a transparent front electrode disposed over the perforated sheet;
- a medium disposed within the cavity formed between the transparent outer sheet and the rear electrode;
- a plurality of electrophoretically mobile particles suspended in the medium;
- and
- a voltage source in communication to the front and the rear electrodes to selectively move the electrophoretically mobile particles in the fluid.
A method to switch from a dark state to a light state at a pixel, the method comprising:
- biasing a top electrode relative to a rear electrode at a first charge to form a substantially undisturbed electromagnetic field in a cavity formed between the top and the rear electrodes, the undisturbed electric field to attract a plurality of electrophoretically charged particles to a semi-retro-reflective surface;
- biasing the top electrode relative to the rear electrode at a second charge to substantially attract the plurality of electrophoretically charged particles to the rear electrode to thereby form the light state;
- modulating an incoming light at the semi-retro-reflective surface to provide a substantially non-Lambertian light display.
A method for switching a front light source illuminated pixel from a dark state to a light state, comprising:
- biasing a top electrode relative to a rear electrode at a first charge to form a substantially undisturbed electromagnetic field in a cavity formed between the first and the second electrodes, the undisturbed electric field to attract a plurality of electrophoretically charged particles to the top surface further comprising convex protrusions of the top electrode to absorb incident light and thereby form a dark state;
- and
- biasing the top electrode relative to the rear electrode at a second charge to cause attraction of the plurality of electrophoretically charged particles to the surface of the rear electrode to thereby form the light state.
Dependencies are inferred from the claim text.