# US 9,436,058 B2 · Electrophoretic display film for anti-counterfeit application > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,436,058 B2 - Document ID: US9436058B2 - Status: Granted - Kind: B2 - Application number: 14/852,351 - Filed: 2015-09-11 - Published: 2016-01-07 - Granted: 2016-09-06 - Earliest claimed: 2013-09-09 - Assignees: E Ink California, LLC - Applicants: E Ink California, LLC - Inventors: Yu Li; HongMei Zang - Web page: https://patentgrep.com/patent/US9436058B2 ## CPC - G02F 1/167: by electrophoresis - B42D 25/00: Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof (printing processes to produce identification or security features B41M3/14) - B42D 25/30: Identification or security features, e.g. for preventing forgery - G02F 1/1681: having two or more microcells partitioned by walls, e.g. of microcup type - G02F 2201/50: Protective arrangements - G02F 2201/501: Blocking layers, e.g. against migration of ions - G02F 2201/503: Arrangements improving the resistance to shock - G02F 2202/04: dye - 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 - B42D: BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS ## Abstract The present invention is directed to an electrophoretic display film which can be controlled to malfunction permanently within a period of time. It provides an elegant method to utilize an electrophoretic film for anti-counterfeit purposes. The concept involves the removal of strong barrier layer(s) from the film to allow the solvent in the electrophoretic fluid within the film to evaporate through weak barrier layer(s), and within a period of time, the performance of the display film will be significantly degraded and the film cannot be re-used. ## Claims ### Claim 1 A method for protecting against counterfeit, comprising: providing a module comprising an electrophoretic display film which film comprises a microcup layer having (i) partition walls, (ii) a microcup bottom layer, and (iii) microcups filled with an electrophoretic fluid comprising charged pigment particles dispersed in a solvent, and the microcup layer is sandwiched between a first stack of layers and a second stack of layers, wherein the partition walls and the microcup bottom layer are weak barrier layers, and each of the two stacks comprises at least a strong barrier layer, and removing one or more the strong barrier layers from the first stack of layers or removing one or more the strong barrier layers from the second stack of layers, or both, allowing the solvent to evaporate from the display film. ### Claim 2 (depends on 1) The method of claim 1, wherein the first stack of layers comprises a sealing layer, an adhesive layer, a first electrode layer and optionally a first protective layer. ### Claim 3 (depends on 1) The method of claim 1, wherein the second stack of layers comprises a primer layer, a second electrode layer, a substrate layer and optionally a second protective layer. ### Claim 4 (depends on 1) The method of claim 1, wherein the solvent is a hydrocarbon solvent. ### Claim 5 (depends on 4) The method of claim 4, wherein a weak barrier layer has a polarity similar to that of the hydrocarbon solvent while a strong barrier layer has a polarity different from that of the hydrocarbon solvent. ### Claim 6 (depends on 4) The method of claim 4, wherein a weak barrier layer is prepared from a hydrophobic material or includes a significant amount of hydrophobic functional groups or linkages, whereas a strong barrier layer is prepared from a hydrophilic material or includes a significant amount of hydrophilic functional groups or linkages. ### Claim 7 (depends on 4) The method of claim 4, wherein a strong barrier layer is formed from a water soluble polymer. ### Claim 8 (depends on 4) The method of claim 4, wherein a weak barrier layer is formed from a material selected from the group consisting of polyurethanes, acrylate polymers and epoxy resins. ### Claim 9 (depends on 1) The method of claim 1, wherein the solvent is a fluorinated solvent. ### Claim 10 (depends on 9) The method of claim 9, wherein a strong barrier layer is formed from a material selected from the group consisting of non-fluorinated thermoplastic or thermoset precursors. ### Claim 11 (depends on 9) The method of claim 9, wherein a weak barrier layer is formed from a material selected from the group consisting of fluorinated polymers and precursors thereof. ### Claim 12 (depends on 1) The method of claim 1, wherein one of the layers is an electrode layer which, as a strong barrier layer, is formed from a material selected from the group consisting of indium tin oxide, aluminum doped zinc oxide and indium doped cadmium oxide. ### Claim 13 (depends on 1) The method of claim 1, wherein one of the layers is an electrode layer which, as a weak barrier layer, is formed from a conductive polymer. ### Claim 14 A method for protecting against counterfeit, comprising: providing a module comprising an electrophoretic display film which film comprises a microcup layer having (i) partition walls, (ii) a microcup bottom layer, and (iii) microcups filled with an electrophoretic fluid comprising charged pigment particles dispersed in a solvent, wherein the microcup layer is sandwiched between a first stack of layers and a second stack of layers, the partition walls and the microcup bottom layer are strong barrier layers and the first stack of layers comprises at least one strong barrier layer and a sealing layer which is a weak barrier; and removing one or more strong barrier layers in the first stack of layers, allowing the solvent to evaporate from the display film.