Color display device
First Claim
1. A display layer comprising an electrophoretic fluid sandwiched between a common electrode and a layer of pixel electrodes and having first and second surfaces on opposed sides thereof, the electrophoretic fluid comprising a first type of particles, a second type of particles and a third type of particles, all dispersed in a solvent or solvent mixture, the first, second and third types of particles having respectively first, second and third optical characteristics differing from one another, the first type of particles having a charge of one polarity and the second and third types of particles having charges of the opposite polarity, and the second type of particles having a threshold voltage, such that:
- (a) application of a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is greater than the threshold voltage and has the same polarity as that of the second type of particles, causes an area corresponding to the pixel electrode to display the second optical characteristic at the first surface;
(b) application of a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is greater than the threshold voltage and has the same polarity as that of the first type of particles, causes an area corresponding to the pixel electrode to display the first optical characteristic at the first surface;
or(c) once the first optical characteristic is displayed at the first surface, application of a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is the same as, or lower than, the threshold voltage and has the same polarity as that of the third type of particles, causes an area corresponding to the pixel electrode to display the third optical characteristic at the first surface.
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Accused Products
Abstract
The present invention provides a solution for a highlight or multicolor display device, in which each display cell can display high quality color states. More specifically, an electrophoretic fluid is provided which comprises three types of pigment particles, having different levels of size, threshold voltage or charge intensity.
205 Citations
20 Claims
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1. A display layer comprising an electrophoretic fluid sandwiched between a common electrode and a layer of pixel electrodes and having first and second surfaces on opposed sides thereof, the electrophoretic fluid comprising a first type of particles, a second type of particles and a third type of particles, all dispersed in a solvent or solvent mixture, the first, second and third types of particles having respectively first, second and third optical characteristics differing from one another, the first type of particles having a charge of one polarity and the second and third types of particles having charges of the opposite polarity, and the second type of particles having a threshold voltage, such that:
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(a) application of a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is greater than the threshold voltage and has the same polarity as that of the second type of particles, causes an area corresponding to the pixel electrode to display the second optical characteristic at the first surface; (b) application of a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is greater than the threshold voltage and has the same polarity as that of the first type of particles, causes an area corresponding to the pixel electrode to display the first optical characteristic at the first surface;
or(c) once the first optical characteristic is displayed at the first surface, application of a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is the same as, or lower than, the threshold voltage and has the same polarity as that of the third type of particles, causes an area corresponding to the pixel electrode to display the third optical characteristic at the first surface. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A driving method for a display layer comprising an electrophoretic fluid sandwiched between a common electrode and a layer of pixel electrodes and having first and second surfaces on opposed sides thereof, the electrophoretic fluid comprising a first type of particles, a second type of particles and a third type of particles, all dispersed in a solvent or solvent mixture, the first, second and third types of particles having respectively first, second and third optical characteristics differing from one another, the first type of particles having a charge of one polarity and the second and third types of particles having charges of the opposite polarity, and the second type of particles having a threshold voltage, which method comprises:
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(a) applying a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is greater than the threshold voltage and has the same polarity as that of the second type of particles, to cause an area corresponding to the pixel electrode to display the second optical characteristic at the first surface; (b) applying a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is greater than the threshold voltage and has the same polarity as that of the first type of particles, to cause an area corresponding to the pixel electrode to display the first optical characteristic at the first surface;
or(c) once the first optical characteristic is displayed at the first surface, applying a voltage potential difference between the common electrode and a pixel electrode, which voltage potential difference is the same as, or lower than, the threshold voltage and has the same polarity as that of the third type of particles, to cause an area corresponding to the pixel electrode to display the third optical characteristic at the first surface. - View Dependent Claims (16, 17, 18)
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- 19. A driving method for a display layer comprising an electrophoretic fluid sandwiched between a common electrode and a layer of pixel electrodes and having first and second surfaces on opposed sides thereof, the electrophoretic fluid comprising a first type of particles, a second type of particles and a third type of particles, all dispersed in a solvent or solvent mixture, the first, second and third types of particles having respectively first, second and third optical characteristics differing from one another, the first type of particles having a charge of one polarity and the second and third types of particles having charges of the opposite polarity, and the second type of particles having a threshold voltage, which method comprises driving an area corresponding to a pixel electrode from a color state of the first type of particles to a color state of the third type of particles by applying a voltage potential difference between the common electrode and the pixel electrode, which voltage potential difference is the same as, or weaker than, the threshold voltage of the second type of particles.
Specification