Color display device and driving methods therefor
AssigneeE Ink California, LLC
InventorCraig Lin
Life of this patent
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Abstract
The invention relates to electrophoretic layers containing at least five different particles, and to driving methods for displaying at least five, and in some embodiments, six different colors at each pixel or sub-pixel. The electrophoretic layers may also contain uncharged neutral buoyancy particles, and the driving methods may include special shaking waveform sequences.
Claims7
A method of driving a display layer having a first surface, which forms a viewing surface of the display layer, and a second surface on the opposed side of the display layer from the first surface, the display layer being provided with means for applying an electric field between the first and second surfaces, the display layer further comprising an electrophoretic medium comprising a fluid and first, second, third, fourth and fifth types of particles dispersed in the fluid, the first, second, third, fourth and fifth types of particles having respectively first, second, third, fourth and fifth optical characteristics differing from one another, the first, third and fourth type of particles having charges of one polarity and the second and fifth types of particles having charges of the opposite polarity, the method comprising:
- (i) applying a first electric field for a period sufficient to cause the optical characteristic of one of the first or second particles to be displayed at the viewing surface;
- (ii) thereafter, applying a second electric field having a polarity opposite to that of the first electric field for a period insufficient to cause the optical characteristic of the other of the first or second particles to be displayed at the viewing surface;
- and
- (iii) thereafter, applying a shaking waveform,
- the driving method further comprising, after the shaking waveform either:
- (iv) applying a third electric field having a polarity driving the first type of particles towards the viewing surface, thereby causing the display layer to display the first optical characteristic at the viewing surface;
- or
- (v) applying a fourth electric field having a polarity driving the second type of particles towards the viewing surface, thereby causing the display layer to display the second optical characteristic at the viewing surface.
A method of driving a display layer having a first surface, which forms a viewing surface of the display layer, and a second surface on the opposed side of the display layer from the first surface, the display layer being provided with means for applying an electric field between the first and second surfaces, the display layer further comprising an electrophoretic medium comprising a fluid and first, second, third, fourth, fifth and sixth types of particles dispersed in the fluid, the first, second, third, fourth, fifth and sixth types of particles having respectively first, second, third, fourth, fifth and sixth optical characteristics differing from one another, the first, third and fourth type of particles having charges of one polarity and the second, fifth and sixth types of particles having charges of the opposite polarity, the method comprising:
- (i) applying a first electric field for a period sufficient to cause the optical characteristic of one of the first or second particles to be displayed at the viewing surface,
- (ii) thereafter, applying a second electric field having a polarity opposite to that of the first electric field for a period insufficient to cause the optical characteristic of the other of the first or second particles to be displayed at the viewing surface;
- and
- (iii) thereafter, applying a shaking waveform,
- the driving method, further comprising, after the shaking waveform, either:
- (iv) applying a third electric field having a polarity driving the first type of particles towards the viewing surface, thereby causing the display layer to display the first optical characteristic at the viewing surface;
- or
- (v) applying a fourth electric field having a polarity driving the second type of particles towards the viewing surface, thereby causing the display layer to display the second optical characteristic at the viewing surface.
Dependencies are inferred from the claim text.