Electrophoretic displays containing magnetic particles
First Claim
1. An electrophoretic medium comprising a plurality of one or more types of particles suspended in suspending fluid, said particles including at least one first magnetic, electrically charged, electrophoretically mobile particle capable of translating through the suspending fluid upon application of an electric field to the medium, the magnetic, electrophoretically mobile particle having a first charge polarity and a first optical characteristic, a second type of particle which is non-magnetic, has a charge polarity opposite of the first charge polarity and has second optical characteristic different from the first optical characteristic, and a third type of particle which is non-magnetic, has a third electrophoretic mobility different from the first and second electrophoretic mobilities and a third optical characteristic different from the first and second optical characteristics.
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Accused Products
Abstract
An electrophoretic medium comprises a plurality of one or more types of particles suspended in a suspending fluid. The particles include at least one electrically charged, electrophoretically mobile particle capable of translating through the suspending fluid upon application of an electric field to the medium and at least one magnetic particle. A magnet is disposed adjacent the electrophoretic medium to introduce a threshold resistance to magnetic particle movement.
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Citations
38 Claims
- 1. An electrophoretic medium comprising a plurality of one or more types of particles suspended in suspending fluid, said particles including at least one first magnetic, electrically charged, electrophoretically mobile particle capable of translating through the suspending fluid upon application of an electric field to the medium, the magnetic, electrophoretically mobile particle having a first charge polarity and a first optical characteristic, a second type of particle which is non-magnetic, has a charge polarity opposite of the first charge polarity and has second optical characteristic different from the first optical characteristic, and a third type of particle which is non-magnetic, has a third electrophoretic mobility different from the first and second electrophoretic mobilities and a third optical characteristic different from the first and second optical characteristics.
- 23. An electrophoretic medium comprising a plurality of one or more types of particles suspended in suspending fluid, said particles including at least one electrically charged, electrophoretically mobile particle capable of translating through the suspending fluid upon application of an electric field to the medium, and at least one magnetic particle comprising a core of magnetic material and a shell of non-magnetic material substantially completely surrounding the core.
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26. A method of addressing electrophoretic medium, the method comprising:
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(a) providing an electrophoretic medium having opposed first and second surfaces, the medium comprising a suspending fluid having a first optical characteristic, and a plurality of electrically charged magnetic particles suspended in the suspending fluid, the particles having a second optical characteristic different from the first optical characteristic, the medium having a magnet disposed adjacent its first surface;
(b) allowing the particles to remain adjacent the first face of the display under the magnetic forces applied to the particles by the magnet, thereby causing the first optical characteristic of the fluid to be visible at the second surface of the medium; and
(c) applying to the medium an electric field having a polarity and magnitude sufficient to cause the particles to move through the suspending fluid against the magnetic forces applied to the particles by the magnet, thereby causing the particles to move adjacent the second surface of the medium and the second optical characteristic of the particles to be visible at the second surface.
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27. A method of addressing electrophoretic medium, the method comprising:
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(a) providing an electrophoretic medium having opposed first and second surfaces, the medium comprising a suspending fluid, a plurality of a first type of electrically charged magnetic particles having a first optical characteristic suspended in the suspending fluid, and a plurality of a second type of electrically charged non-magnetic particle having a second optical characteristic different from the first optical characteristic, the second type of particles bearing charges of opposite polarity to the charges on the first type of particles, the medium having a magnet disposed adjacent its first surface; (b) applying to the medium an electric field having a polarity which causes the second type of particles to move adjacent the second surface a the medium, while causing the first type of particles to remain adjacent the first surface of the medium, thereby causing the second optical characteristic to be visible at the second surface; and
(c) applying to the medium an electric field having a polarity and magnitude sufficient to cause the first particles to move through the suspending fluid against the magnetic forces applied to the first particles by the magnet, thereby causing the first particles to move adjacent the second surface of the medium and the first optical characteristic to be visible at the second surface, while the second particles move adjacent the first surface of the medium. - View Dependent Claims (28, 29)
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30. A method of addressing an electrophoretic medium, the method comprising:
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(a) providing an electrophoretic medium having opposed first and second surfaces, the medium comprising a suspending fluid, a plurality of a first type of electrically charged magnetic particles having a first optical characteristic suspended in the suspending fluid, a plurality of a second type of electrically charged non-magnetic particles having a second optical characteristic different from the first optical characteristic, the first and second types of particles bearing charges of the same polarity, and a third type of electrically charged non-magnetic particles having a third optical characteristic different from the first and second optical characteristics, the third type of particles bearing charges of opposite polarity to those on the first and second types of particles;
the medium having a magnet disposed adjacent its first surface;
(b) applying to the medium an electric field having a polarity which causes the third type of particles to move adjacent the second surface of the medium, while causing the first and second types of particles to remain adjacent the first surface of the medium, thereby causing the third optical characteristic to be visible at the second surface;
(c) applying to the medium an electric field having a polarity and magnitude sufficient to cause the second type of particles to move adjacent the second surface of the medium and the third type of particles to move adjacent the first surface of the medium, but insufficient to cause the first type of particles to move away from the first surface of the medium against the magnetic forces acting on the first type of particles, thereby causing the second optical characteristic to be visible at the second surface; and
(d) applying to the medium an electric field having a polarity and magnitude sufficient to cause the second type of particles to move adjacent the second surface of the medium and the third type of particles to move adjacent the first surface of the medium, the magnitude of the electric field being sufficient to cause the first type of particles to move away from the first surface of the medium against the magnetic forces acting on the first type of particles and lie adjacent the second surface of the medium, thereby causing the first and second optical characteristics to be visible at the second surface.
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31. A method of addressing an electrophoretic medium, the method comprising:
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(a) providing an electrophoretic medium having opposed first and second surface, the medium comprising a suspending fluid, a plurality of a first type of electrically charged magnetic particles having a first optical characteristic suspended in the suspending fluid, a plurality of a second type of electrically charged non-magnetic particles having a second optical characteristic different from the first optical characteristic, the first and second types of particles bearing charges of opposite polarity, and a plurality of a third type of electrically charged non-magnetic particles having a third optical characteristic different from the first and second optical characteristics, the second and third types of particles bearing charges of the same polarity, but the second type of particles having higher electrophoretic mobility than the third type of particle;
the medium having a magnet disposed adjacent its first surface;
(b) applying to the medium an electric field having a polarity which causes the second and third types of particles to move adjacent the second surface of the medium with the second type of particles lying closer to the second surface, so that the second optical characteristic is visible at the second surface, the first type of particles lying adjacent the first surface of the medium;
(c) applying to the medium an electric field having a polarity and magnitude sufficient to cause the second and third types of particles to move adjacent the first surface of the display, with the third type of particles lying closer to the second surface, the magnitude of the electric field being insufficient to cause the first type of particles to move away from the first surface of the medium against the magnetic forces acting on the first type of particles, thereby causing the third optical characteristic to be visible at the second surface; and
(d) applying to the medium an electric field having a polarity and magnitude sufficient to cause the second and third types of particles to move adjacent the first surface of the medium, the magnitude of the electric field being sufficient to cause the first type of particles to move away from the first surface of the medium against the magnetic forces acting on the first type of particles and lie adjacent the second surface of the medium, thereby causing the first optical characteristic to be visible at the second surface.
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32. A method of driving an electrophoretic medium to provide a threshold and/or to increase the number of optical states which can be displayed by the medium, the method comprising:
- providing an electrophoretic medium having opposed first and second surfaces, the medium comprising a suspending fluid having a first optical characteristic, and a plurality of electrically charged magnetic particles suspended in the suspending fluid, the medium having a magnet disposed adjacent its first surface;
applying to the medium an electric field having a polarity and magnitude which tends to cause the particles to move towards the second surface of the medium but which is insufficient to overcome the magnetic forces applied to the particles by the magnet, thereby the particles to remain adjacent the first surface of the medium; and
applying to the medium an electric field having a polarity and magnitude sufficient to cause the particles to move through the suspending fluid against the magnetic forces applied to the particles by the magnet, thereby causing the particles to move adjacent the second surface of the medium, the optical state of the medium varying depending upon whether the particles are adjacent the first or second surface of the medium.
- providing an electrophoretic medium having opposed first and second surfaces, the medium comprising a suspending fluid having a first optical characteristic, and a plurality of electrically charged magnetic particles suspended in the suspending fluid, the medium having a magnet disposed adjacent its first surface;
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33. An electrophoretic display comprising:
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a layer of an electrophoretic medium comprising a plurality of one or more types of particles suspended in a suspending fluid, said particles including at least one electrically charged, electrophoretically mobile particle capable of translating through the suspending fluid upon application of an electric field to the medium, and at least one magnetic particle;
a first electrode disposed adjacent one side of the layer of electrophoretic medium;
a magnet disposed adjacent the said one said of the layer of electrophoretic medium; and
a second electrode disposed adjacent the layer of electrophoretic medium on the opposed side thereof from the first electrode and the magnet. - View Dependent Claims (34, 35, 36, 37, 38)
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Specification