# US 8,786,935 B2 · Color electrophoretic display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,935 B2 - Document ID: US8786935B2 - Status: Granted - Kind: B2 - Application number: 13/482,913 - Filed: 2012-05-29 - Published: 2012-12-06 - Granted: 2014-07-22 - Earliest claimed: 2011-06-02 - Assignees: SiPix Imaging, Inc. - Applicants: Robert Sprague - Inventors: Robert Sprague - Web page: https://patentgrep.com/patent/US8786935B2 ## CPC - G02F 1/167: by electrophoresis - G02F 2203/34: Colour display without the use of colour mosaic filters - G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS ## Abstract The present invention is directed to a color display device wherein each of the display cells is filled with an electrophoretic fluid comprising two types of charged pigment particles dispersed in a colored medium. Multiple colors of high quality may be achieved by the present invention. ## Claims ### Claim 1 A display device comprising display cells, wherein each of said display cells is a) sandwiched between a first layer comprising a common electrode and a second layer comprising a pixel electrode, and b) filled with a display fluid comprising a first type of pigment particles which is white and a second type of pigment particles which is red, green or blue, and said two types of pigment particles are oppositely charged and are dispersed in a black solvent, wherein said black solvent comprises non-charged or slightly charged black particles dispersed in a clear and colorless solvent. ### Claim 2 (depends on 1) The display device of claim 1, wherein said white pigment particles are formed from TiO2. ### Claim 3 (depends on 1) The display device of claim 1, wherein at least one type of the pigment particles are encapsulated pigment particles. ### Claim 4 (depends on 1) The display device of claim 1, wherein said display fluid further comprises a charge control agent. ### Claim 5 (depends on 1) The display device of claim 1, wherein said non-charged or slightly charged black particles are substantially transparent. ### Claim 6 (depends on 1) The display device of claim 1, wherein the non-charged or slightly charged black particles have a zeta potential of <20. ### Claim 7 (depends on 1) The display device of claim 1, wherein the non-charged or slightly charged black particles are polymeric and are in the form of a transparent polymeric matrix, with dye molecules embedded in the matrix. ### Claim 8 (depends on 1) The display device of claim 1, wherein each display cell defines a sub-pixel and three sub-pixels forms a pixel. ### Claim 9 A display device comprising display cells, wherein each of said display cells is a) sandwiched between a first layer comprising a common electrode and a second layer comprising a pixel electrode, and b) filled with a display fluid comprising a first type of pigment particles which is white and a second type of pigment particles which is red, green or blue, and said two types of pigment particles are oppositely charged and are dispersed in a colored solvent which has a color complementary to the color of the second type of pigment particles, wherein the colored solvent comprises non-charged or slightly charged colored particles dispersed in a clear and colorless solvent. ### Claim 10 (depends on 9) The display device of claim 9, wherein each display cell defines a sub-pixel and three sub-pixels form a pixel. ### Claim 11 (depends on 9) The display device of claim 9, wherein said display fluid further comprises a charge control agent. ### Claim 12 (depends on 9) The display device of claim 9, wherein said non-charged or slightly charged colored particles are substantially transparent. ### Claim 13 (depends on 9) The display device of claim 9, wherein the non-charged or slightly charged colored particles have a zeta potential of <20. ### Claim 14 (depends on 9) The display device of claim 9, wherein the non-charged or slightly charged colored particles are polymeric and are in the form of a transparent polymeric matrix, with dye molecules embedded in the matrix. ### Claim 15 A display device comprising display cells and a white background layer, wherein each of said display cells is a) sandwiched between a first layer comprising a common electrode and a second layer comprising a pixel electrode and at least one in-pane electrode, and b) filled with a display fluid comprising a first type of pigment particles which are white and a second type of pigment particles which are red, green or blue, and said two types of pigment particles are oppositely charged and are dispersed in a colored solvent which has a color complementary to the color of the second type of pigment particles, wherein the colored solvent comprises non-charged or slightly charged colored particles dispersed in a clear and colorless solvent. ### Claim 16 (depends on 15) The display device of claim 15, wherein each display cell defines a sub-pixel and two sub-pixels form a pixel. ### Claim 17 (depends on 15) The display device of claim 15, wherein said display fluid further comprises a charge control agent. ### Claim 18 (depends on 15) The display device of claim 15, wherein said non-charged or slightly charged colored particles are substantially transparent. ### Claim 19 (depends on 15) The display device of claim 15, wherein the non-charged or slightly charged colored particles have a zeta potential of <20. ### Claim 20 (depends on 15) The display device of claim 15, wherein the non-charged or slightly charged colored particles are polymeric and are in the form of a transparent polymeric matrix, with dye molecules embedded in the matrix.