# US 7,612,845 B2 · Polarizing plate with an optical compensation layer, method of producing the same, and liquid crystal panel, liquid crystal display apparatus, and image display apparatus, using the polarizing plate with an optical compensation layer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,845 B2 - Document ID: US7612845B2 - Status: Granted - Kind: B2 - Application number: 11/995,402 - Filed: 2006-07-05 - Published: 2009-05-21 - Granted: 2009-11-03 - Earliest claimed: 2005-07-13 - Assignees: Nitto Denko Corporation - Inventors: Takuya Mori; Yoshitsugu Kitamura; Mariko Hirai; Naoki Takahashi - Web page: https://patentgrep.com/patent/US7612845B2 ## CPC - G02B 5/305: {including organic materials, e.g. polymeric layers} - G02F 1/13363: Birefringent elements, e.g. for optical compensation - G02F 1/133528: {Polarisers} - G02F 1/133634: {the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis} - G02F 1/133635: {Multifunctional compensators} - G02F 2202/40: Materials having a particular birefringence, retardation - G02F 2413/04: Number of plates greater than or equal to 4 - G02F 2413/07: All plates on one side of the LC cell - G02F 2413/10: with refractive index ellipsoid inclined, or tilted, relative to the LC-layer surface O plate - G02F 2413/13: Positive birefingence - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - 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 There is provided a polarizing plate with optical compensation layers that contributes to reduction in thickness and has excellent heat resistance and moisture resistance. A polarizing plate with optical compensation layers according to an embodiment of the present invention includes: a polarizer; a first optical compensation layer; a second optical compensation layer; and a third optical compensation layer, in this order. The first optical compensation layer has a refractive index profile of nx>ny=nz, and an in-plane retardation Re1 of 200 to 300 nm; the second optical compensation layer has a refractive index profile of nx>ny=nz, and an in-plane retardation Re2 of 80 to 170 nm; and the third optical compensation layer is formed of a material exhibiting an optical negative uniaxial property, and the material is aligned so as to be inclined. ## Claims ### Claim 1 A polarizing plate with optical compensation layers, comprising: a polarizer; a first optical compensation layer; a second optical compensation layer; and a third optical compensation layer, in this order, wherein: the first optical compensation layer has a refractive index profile of nx>ny=nz, and an in-plane retardation Re1 of 200 to 300 nm; the second optical compensation layer has a refractive index profile of nx>ny=nz, and an in-plane retardation Re2 of 80 to 170 nm; and the third optical compensation layer is formed of a material exhibiting an optical negative uniaxial property, and the material is aligned so as to be inclined. ### Claim 2 (depends on 1) A polarizing plate with optical compensation layers according to claim 1, wherein the second optical compensation layer and the third optical compensation layer are attached to each other via only an adhesive layer. ### Claim 3 (depends on 1) A polarizing plate with optical compensation layers according to claim 1, wherein the third optical compensation layer has a thickness of 1 to 10 μm. ### Claim 4 (depends on 1) A polarizing plate with optical compensation layers according to claim 1, wherein the first optical compensation layer and the second optical compensation layer respectively contains a norbornene-based resin and/or a polycarbonate-based resin. ### Claim 5 (depends on 1) A polarizing plate with optical compensation layers according to claim 1, wherein the material exhibiting an optically negative uniaxial property comprises a discotic liquid crystal compound. ### Claim 6 (depends on 1) A polarizing plate with optical compensation layers according to claim 1, wherein the material exhibiting an optically negative uniaxial property for the third optical compensation layer has an average optical axis inclined at an angle of 5° to 50° with respect to a normal line direction of the third optical compensation layer. ### Claim 7 (depends on 1) A liquid crystal panel, comprising: the polarizing plate with optical compensation layers according to claim 1; and a liquid crystal cell. ### Claim 8 (depends on 7) A liquid crystal display apparatus, comprising the liquid crystal panel according to claim 7. ### Claim 9 (depends on 1) An image display apparatus, comprising the polarizing plate with optical compensation layers according to claim 1. ### Claim 10 A production method for a polarizing plate with optical compensation layers, the production method comprising the steps of: preparing a laminate including an inclined alignment layer in which a material exhibiting an optically negative uniaxial property is aligned so as to be inclined, and a base material; attaching a second optical compensation layer having a refractive index profile of nx>ny=nz and an in-plane retardation Re2 of 80 to 170 nm to the laminate such that the second optical compensation layer and the inclined alignment layer are adjacent to each other; peeling the base material, and setting the inclined alignment layer to be a third optical compensation layer; attaching a first optical compensation layer having a refractive index profile of nx>ny=nz and an in-plane retardation Re1 of 200 to 300 nm; and attaching a polarizer. ### Claim 11 (depends on 10) A production method according to claim 10, wherein the step of attaching the second optical compensation layer to the laminate includes attaching the second optical compensation layer to the inclined alignment layer with an adhesive strength higher than an adhesive strength between the inclined alignment layer and the base material. ### Claim 12 (depends on 10) A production method according to claim 10, wherein the step of peeling the base material includes immersing the laminate in a water bath. ### Claim 13 (depends on 12) A production method according to claim 12, wherein a temperature of the water bath is 50 to 100° C. ### Claim 14 (depends on 12) A production method according to claim 12, wherein a time period of the immersing is 3 to 30 minutes.