Transmissive electrophoretic display with stacked color cells
AssigneeInternational Business Machines Corporation
InventorsJoseph G. Gordon, II, Mark W. Hart, Anthony C. Lowe, Sally A. Swanson
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Abstract
A transmissive color electrophoretic display incorporated with a backlight, has a plurality of laterally adjacent picture elements or pixels. Each pixel is comprised of two or more subpixels, or cells, which are vertically stacked, one directly above the other on the horizontal surface of a reflective panel located at the rear or bottom of the stacks. The cells contain a light-transmissive fluid and charged pigment particles that can absorb a portion of the visible spectrum, with each cell in a stack containing particles having a color different from the colors of the particles in the other cells in the stack.
Claims20
A color electrophoretic display comprising:
- a substantially planar light-transmissive rear panel;
- a substantially planar light-transmissive front window generally parallel to and spaced from the rear panel;
- a plurality of pixels laterally adjacent to one another and located in the space between the rear panel and the front window, each pixel comprising multiple cells stacked from the rear panel to the front window, each cell in the stack containing charged, light-absorbing pigment particles in a light-transmissive fluid, and all laterally adjacent cells from different pixels forming layers of cells with each layer having pigment particles of the same color;
- a collecting electrode substantially non-obstructing to light and associated with each cell to substantially remove pigment particles in the associated cell from the path of light through the cell;
- and
- a counter electrode substantially non-obstructing to light and associated with each collecting electrode to distribute the pigment particles throughout the light-transmissive fluid of the associated cell so as to be in the path of light through the cell.
A reflective color electrophoretic display comprising:
- a light-transmissive rear panel having a substantially planar horizontal surface;
- a substantially planar light-transmissive front window generally parallel to and spaced from the horizontal surface of the rear panel;
- first and second substantially planar light-transmissive plates located between the rear panel and front window and generally parallel to the horizontal surface of the rear panel;
- a plurality of vertical side walls for spacing the first plate from the horizontal surface of the rear panel, the second plate from the first plate, and the front window from the second plate, the vertical side walls defining a plurality of stacks of three vertically-aligned cells, each cell in a stack containing a light-transmissive fluid and charged, light-absorbing pigment particles having a color different from the color of the pigment particles in the other two cells in the stack, each stack thereby forming a multicolored pixel;
- an electrode on the cell-interior surface of the vertical side walls for collecting the charged pigment particles to substantially remove them from the path of light through the cell;
- a counter electrode in each cell for distributing the pigment particles throughout the light-transmissive fluid of the cell to place the particles in the path of light through the cell;
- a plurality of counter electrode driving elements on the horizontal surface of the rear panel, each driving element being associated with and electrically connected to a counter electrode;
- and
- a backlight located behind the light-transmissive rear panel for passing light through the rear panel and the cells to the front window for observation by a viewer of the display.
Dependencies are inferred from the claim text.