# US RE44,315 E1 · Polarizing film and image display > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US RE44,315 E1 - Document ID: USRE44315E1 - Status: Granted - Kind: E1 - Application number: 13/557,830 - Filed: 2012-07-25 - Granted: 2013-06-25 - Earliest claimed: 2002-01-18 - Assignees: Nitto Denko Corporation - Applicants: Youichirou Sugino; Hisashi Mihara; Kazuhiro Higashio; Seiichi Kusumoto - Inventors: Youichirou Sugino; Hisashi Mihara; Kazuhiro Higashio; Seiichi Kusumoto - Web page: https://patentgrep.com/patent/USRE44315E1 ## Abstract The present invention provides a polarizing film or a polarizer that has an elastic modulus of at most about 3500 N/mm2 and suppresses occurrence of warping, the polarizing film is obtained by adsorbing a dichroic material in a polyvinyl alcohol-based film 20 μm in thickness and stretching the film. The polarizing film has a transmittance of at least 43% and a polarization degree of at least 98%. A transparent protective layer is laminated on at least one surface of the polarizing film to form a polarizing plate. ## Claims ### Claim 1 A polarizing film which transmits a light having a first polarization and does not transmit light having a second polarization, the polarizing film having an elastic modulus of at most about 3500 N/mm2, wherein the polarizing film comprises a polarizer, wherein the polarizer is a stretched film having a thickness of at most 20 μm, and a transparent protective layer laminated on at least one surface of the polarizer. ### Claim 2 (depends on 1) The polarizing film according to claim 1, wherein a dichroic material is adsorbed in the stretched film. ### Claim 3 (depends on 1) The polarizing film according to claim 1, wherein the stretched film is a polarizer. ### Claim 4 (depends on 1) The polarizing film according to claim 1, having a transmittance of at least 43%. ### Claim 5 (depends on 1) The polarizing film according to claim 1, having a polarization degree of at least 98%. ### Claim 6 (depends on 1) The polarizing film according to claim 1, wherein the stretched film is a polyvinyl alcohol-based film. ### Claim 7 (depends on 1) The polarizing film according to claim 1, wherein the stretched film is prepared by stretching an unstretched film having a thickness of at most 50 μm. ### Claim 8 (depends on 7) The polarizing film according to claim 7, wherein the stretched film has a stretch ratio in the stretching direction ranging 3.0-7.0 with respect to the unstretched film. ### Claim 9 (depends on 7) The polarizing film according to claim 7, wherein the stretched film has a stretch ratio in the stretching direction ranging 5.5-6.0 with respect to the unstretched film. ### Claim 10 (depends on 1) The polarizing film according to claim 1, wherein the transparent protective layer is a polymer film. ### Claim 11 (depends on 1) The polarizing film according to claim 1, further comprising at least one of a reflector and a transflecter. ### Claim 12 (depends on 1) The polarizing film according to claim 1, further comprising a retardation film. ### Claim 13 (depends on 1) The polarizing film according to claim 1, further comprising a viewing-angle compensating film. ### Claim 14 (depends on 1) The polarizing film according to claim 1, further comprising a brightness enhancement film. ### Claim 15 (depends on 1) The polarizing film according to claim 1, having an elastic modulus of at most about 2800 N/mm2. ### Claim 16 (depends on 1) The polarizing film according to claim 1, having an elastic modulus of at most about 2300 N/mm2. ### Claim 17 (depends on 1) The polarizing film according to claim 1, having an elastic modulus of at most about 2000 N/mm2. ### Claim 18 (depends on 1) A liquid crystal panel comprising a liquid crystal cell and the polarizing film of claim 1 arranged on at least one surface of the liquid crystal cell. ### Claim 19 (depends on 18) The liquid crystal panel according to claim 18, wherein the liquid crystal cell comprises a liquid crystal cell substrate and a liquid crystal, the liquid crystal cell substrate being at least one of a glass substrate and a plastic substrate. ### Claim 20 (depends on 18) A liquid crystal display comprising the liquid crystal panel of claim 18. ### Claim 21 (depends on 20) The liquid crystal display according to claim 20, further comprising a light source. ### Claim 22 (depends on 1) An image display comprising an image display panel and the polarizing film according to claim 1. ### Claim 23 (depends on 22) An image display according to claim 22, wherein the image display is selected from the group consisting of a liquid crystal display, a plasma display and an electroluminescence display. ### Claim 24 A method of making a polarizing film, comprising stretching a polymer film so that an elastic modulus of the polarizing film is at most about 2800 N/mm2, wherein the unstretched film has a thickness of at most about 50 μm. ### Claim 25 (depends on 24) The method according to claim 24, wherein the stretched film has a stretch ratio in the stretching direction ranging 3.0-7.0 with respect to the unstretched film. ### Claim 26 (depends on 24) The method according to claim 24, wherein the unstretched film is stretched in a solution containing boric acid and a solution containing borax. ### Claim 27 (depends on 24) The polarizing film according to claim 24, wherein the stretched film has a stretch ratio in the stretching direction ranging 5.5-6.0 with respect to the unstretched film. ### Claim 28 A polarizing film which transmits a light having a first polarization and does not transmit light having a second polarization, the polarizing film having an elastic modulus of at most about 3500 N/mm2, and a transmittance of at least 43%. ### Claim 29 A polarizing film which transmits a light having a first polarization and does not transmit light having a second polarization, the polarizing film having an elastic modulus of at most about 3500 N/mm2, and a polarization degree of at least 98%. ### Claim 30 A polarizing film which transmits a light having a first polarization and does not transmit light having a second polarization, the polarizing film having an elastic modulus of at most about 3500 N/mm2, wherein a dichroic material is absorbed in the stretched film, and the stretched film is prepared by stretching an unstretched film having a thickness of at most 50 μm. ### Claim 31 (depends on 30) The polarizing film according to claim 30, wherein the stretched film has a stretch ratio in the stretching direction ranging 3.0-7.0 with respect to the unstretched film. ### Claim 32 (depends on 30) The polarizing film according to claim 30, wherein the stretched film has a stretch ratio in the stretching direction ranging 5.5-6.0 with respect to the unstretched film.