# US 5,351,143 A · Hand-writable polymer dispersed liquid crystal board set with high resistance layer of crosslinking polymer adjacent conductive layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,351,143 A - Document ID: US5351143A - Status: Granted - Kind: A - Application number: 08/008,735 - Filed: 1993-01-25 - Granted: 1994-09-27 - Earliest claimed: 1992-02-07 - Assignees: Kabushiki Kaisha Pilot Corporation - Inventors: Morio Sato; Yutaka Abe; Jun Takano; Hirokazu Ishii; Yasuzo Murata - Web page: https://patentgrep.com/patent/US5351143A ## CPC - G06F 3/0412: {Digitisers structurally integrated in a display} - G02F 1/133345: {Insulating layers (G02F1/1335, G02F1/1337, G02F1/135, G02F1/136 take precedence)} - G02F 1/133348: {Charged particles addressed liquid crystal cells, e.g. controlled by an electron beam} - G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) - 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 A liquid crystal display device of externally charging type, including a screen from the outside of which display and erasing operations can be repeatedly performed simply, and having an excellent memory retention performance of the recorded image and durability. Also, a hand-writable liquid crystal board set being excellent in operativity, performances, safety, including the above liquid crystal display device as a liquid crystal board. The liquid crystal display device includes a layered structure comprising, in the following order: a conductive layer; a transparent high-electric resistance layer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in a 20.degree. C. air at a relative humidity of 90%; a liquid crystal-dispersed polymer layer which has a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in a 20.degree. C. air at a relative humidity of 90%; and a transparent insulator layer. The hand-writable liquid crystal board set comprises: (A) a board of the above liquid crystal display device, (B) display means for displaying recording images onto the board surface, and erasing means for erasing the recorded images; and (C) a power source for generating a surface potential between the surface of the liquid crystal board and the conductive layer by the display means; wherein the display means employs a writing member electrically connected to one terminal of the power source which is connected at the other terminal to the conductive layer; and the erasing means employs an erasing member electrically connected to the conductive layer. ## Claims ### Claim 1 A liquid crystal display device of externally charging type comprising: a conductive layer; a transparent high-electric resistance layer of a crosslinking polymer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in 20.degree. C. air at a relative humidity of 90%; a liquid crystal-dispersed polymer layer in which liquid crystal is finely dispersed in a polymer matrix, said layer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in 20.degree. C. air at a relative humidity of 90%; and a transparent insulator layer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in 20.degree. C. air at a relative humidity of 90% wherein all of said layers are successively layered in the order presented. ### Claim 2 (depends on 1) The liquid crystal display device of externally charging type according to claim 1, wherein the polymer matrix of said liquid crystal-dispersed polymer layer is composed of a polymer having a cross-linking structure. ### Claim 3 (depends on 1) The liquid crystal display device according to claim 1, wherein said cross-linking polymer making up the high-electric resistance layer is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a cross-linking agent reactive with said functional group. ### Claim 4 (depends on 3) The liquid crystal display device according to claim 3, wherein said polymer is a silicone polymer. ### Claim 5 (depends on 1) The liquid crystal display device according to claim 1, wherein said cross-linking polymer making up the high-electric resistance layer is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a reactive polymer to form a cross-linking polymer. ### Claim 6 (depends on 5) The liquid crystal display device according to claim 5, wherein said polymer is a silicone polymer. ### Claim 7 (depends on 5) The liquid crystal display device according to claim 5, wherein said reactive polymer comprises at least one polymer selected from the group consisting of phenol resin, amino resin, polyisocyanate, polyol and epoxy resin. ### Claim 8 (depends on 1) The liquid crystal display device according to claim 1, wherein said cross-linking polymer making up the high-electric resistance layer is formed by reacting one of a diisocyanate and a polyisocyanate with at least one polymer selected from the group consisting of a polyvinylacetal resin; an epoxy resin; acrylic resins having a hydroxy group or a carboxyl group; a polyester resin; and a fluororesin. ### Claim 9 (depends on 1) The liquid crystal display device according to claim 1, wherein said cross-linking polymer making up the high-electric resistance layer is formed by reacting one of a diisocyanate and a polyisocyanate with polyvinylacetal. ### Claim 10 (depends on 1) The liquid crystal display device according to claim 1, wherein the polymer matrix of said liquid crystal-dispersed polymer layer is composed of a cross-linking polymer which is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a cross-linking agent reactive with said functional group. ### Claim 11 (depends on 10) The liquid crystal display device according to claim 10, wherein said polymer is a silicone polymer. ### Claim 12 (depends on 1) The liquid crystal display device according to claim 1, wherein said polymer matrix of said liquid crystal-dispersed polymer layer comprises a cross-linking polymer which is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a reactive polymer to form a cross-linking polymer. ### Claim 13 (depends on 12) The liquid crystal display device according to claim 12, wherein said polymer is a silicone polymer. ### Claim 14 (depends on 12) The liquid crystal display device according to claim 12, wherein said reactive polymer is selected from the group consisting of phenol resin, amino resin, polyisocyanate, polyol and epoxy resin. ### Claim 15 (depends on 1) The liquid crystal display device according to claim 1, wherein said polymer matrix of said liquid crystal-dispersed polymer layer comprises a cross-linking polymer formed by reacting one of a diisocyanate and a polyisocyanate with at least one polymer selected from the group consisting of a polyvinylacetal resin; an epoxy resin; acrylic resins having a hydroxy group or a carboxyl group; a polyester resin; and a fluororesin. ### Claim 16 (depends on 1) The liquid crystal display device of externally charging type according to claim 1, wherein said polymer matrix of said liquid crystal-dispersed polymer layer comprises a cross-linking polymer formed by reacting one of a diisocyanate and a polyisocyanate with polyvinylacetal. ### Claim 17 A hand-writable liquid crystal board set comprising: (A) a liquid crystal board of the externally charging type, said liquid crystal board comprising: a conductive layer; a transparent high-electric resistance layer of a cross-linking polymer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in 20.degree. C. air at a relative humidity of 90%; a liquid crystal-dispersed polymer layer in which liquid crystal is finely dispersed in a polymer matrix, said liquid crystal-dispersed polymer layer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in 20.degree. C. air at a relative humidity of 90%; and a transparent insulator layer having a volume resistivity of 10.sup.13 .OMEGA..cndot.cm or more in 20.degree. C. air at a relative humidity of 90%, wherein all of said layers are successively layered in the order presented; (B) display means for displaying at least one recorded image onto a surface of said liquid crystal board; (C) erasing means for erasing said recorded image, said erasing means having an erasing member electrically connected to said conductive layer; (D) a power source for generating a surface potential between the surface of said liquid crystal board and said conductive layer; and (E) a writing member electrically connected to one terminal of said power source, said power source having another terminal connected to said conductive layer. ### Claim 18 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein the polymer matrix of said liquid crystal-dispersed polymer layer is composed of a polymer having a cross-linking structure. ### Claim 19 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said writing member, said erasing member, and the electrical connections thereto all have a respective volume resistivity of 10.sup.12 .OMEGA..cndot.cm or less in a 23.degree. C. at a relative humidity of 50%. ### Claim 20 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein an electric resistance of 200 K.OMEGA. to 100 M.OMEGA. is electrically connected at least between one terminal of said power source and said conductive layer, between one terminal of said power source and said erasing member, and between said conductive layer and said erasing member. ### Claim 21 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein an electric circuit including said display means and said erasing means is equipped with an interlock device for preventing the occurrence of electric shocks. ### Claim 22 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein an electric circuit including said display means and said erasing means is equipped with an automatic power-off device. ### Claim 23 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein the surface of said board has been subjected to a dirt-protection treatment. ### Claim 24 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said writing member comprises a stamp having a pattern of a conductive material formed thereon. ### Claim 25 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said writing member and said erasing member have been subjected to a dirt-protection treatment. ### Claim 26 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said erasing member comprises a stamp having a pattern of a conductive material formed thereon. ### Claim 27 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said cross-linking polymer making up the high-electric resistance layer is obtained by reacting a polymer containing a functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a cross-linking agent reactive with said functional group. ### Claim 28 (depends on 27) The hand-writable liquid crystal board set according to claim 27, wherein said polymer is a silicone polymer. ### Claim 29 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said cross-linking polymer making up the high-electric resistance layer is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a reactive polymer to form a cross-linking polymer. ### Claim 30 (depends on 29) The hand-writable liquid crystal board set according to claim 29, wherein said polymer is a silicone polymer. ### Claim 31 (depends on 29) The hand-writable liquid crystal board set according to claim 29, wherein said reactive polymer comprises at least one polymer selected from the group consisting of phenol resin, amino resin, polyisocyanate, polyol and epoxy resin. ### Claim 32 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said cross-linking polymer making up the high-electric resistance layer is formed by reacting one of a diisocyanate and a polyisocyanate with at least one polymer selected from the group consisting of a polyvinylacetal resin; an epoxy resin; acrylic resins having a hydroxy group or a carboxyl group; a polyester resin; and a fluororesin. ### Claim 33 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said cross-linking polymer making up the high-electric resistance layer is formed by reacting one of a diisocyanate and a polyisocyanate with polyvinylacetal. ### Claim 34 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein the polymer matrix of said liquid crystal dispersed polymer layer is composed of a cross-linking polymer which is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a cross-linking agent reactive with said functional group. ### Claim 35 (depends on 34) The hand-writable liquid crystal board set according to claim 34, wherein said polymer is a silicone polymer. ### Claim 36 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said polymer matrix of said liquid crystal-dispersed polymer comprises a cross-linking polymer which is obtained by reacting a polymer containing at least one functional group, wherein said functional group is selected from the group consisting of a double bond, a nitrile group, a mercapto group, a hydroxyl group, a carboxyl group, an epoxy group, an isocyanate group, an amino group and a chlorosulfone group, with a reactive polymer to form a cross-linking polymer. ### Claim 37 (depends on 36) The hand-writable liquid crystal board set according to claim 36, wherein said polymer is a silicone polymer. ### Claim 38 (depends on 36) The hand-writable liquid crystal board set according to claim 36, wherein said reactive polymer is selected from the group consisting of phenol resin, amino resin, polyisocyanate, polyol and epoxy resin. ### Claim 39 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said polymer matrix of said liquid crystal-dispersed polymer layer comprises a cross-linking polymer formed by reacting one of a diisocyanate and a polyisocyanate with at least one polymer selected from the group consisting of a polyvinylacetal resin; an epoxy resin; acrylic resins having a hydroxy group or a carboxyl group; a polyester resin; and a fluororesin. ### Claim 40 (depends on 17) The hand-writable liquid crystal board set according to claim 17, wherein said polymer matrix of said liquid crystal dispersed polymer layer comprises a cross-linking polymer formed by reacting one of a diisocyanate and a polyisocyanate with polyvinylacetal.