# US 9,751,231 B2 · Polarizing film cutting knife and method of manufacturing polarizing plate using the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,751,231 B2 - Document ID: US9751231B2 - Status: Granted - Kind: B2 - Application number: 14/507,598 - Filed: 2014-10-06 - Published: 2015-04-16 - Granted: 2017-09-05 - Earliest claimed: 2013-10-11 - Assignees: Samsung Display Co., Ltd. - Applicants: Samsung Display Co., Ltd. - Inventors: Dong-Wook Kim; Hyun-Hun Jang; Sung-Ho Kang - Web page: https://patentgrep.com/patent/US9751231B2 ## CPC - B26D 1/0006: {Cutting members therefor} - B29D 11/00644: {polarizing} - B26D 2001/002: {Materials or surface treatments therefor, e.g. composite materials} - B26D 2001/0053: {having a special cutting edge section or blade section} - B26D 2001/006: {the cutting blade having a special shape, e.g. a special outline, serrations} - B29L 2011/0066: {Optical filters} - G02B 5/3033: {in the form of a thin sheet or foil, e.g. Polaroid} - Y10T 29/49764: with testing or indicating - Y10T 83/929: Tool or tool with support - B26D: CUTTING; DETAILS COMMON TO MACHINES FOR PERFORATING, PUNCHING, CUTTING-OUT, STAMPING-OUT OR SEVERING (for growing crops or plants A01D, A01G; for fodder or straw A01F; for bulk butter A01J; for dough A21C; slaughtering A22B; for tobacco, cigars or cigarettes A24; marking-out, perforating or making buttonholes A41H25/00; manufacturing footwear A43D; brushmaking A46D; surgery A61B; disintegrating, mincing or shredding in general B02C; cutting wire, making pins or nails B21F, B21G; of the kind used formetal B23; cutting by abrasive fluid jets B24C5/02; hand-held cutting tools B26B; perforating, cutting-out, stamping-out or punching, or severing by means other than cutting B26F; for wood B27; for stone B28D; working of plastics or substances in a plastic state B29; making boxes, cartons, envelopes or bags, of paper or similarly worked materials, e.g. metal foil, B31B; article or web delivery apparatus incorporating cutting or line-perforating devices B65H35/00; for leather or upholstery B68, C14B; for glass C03B; making matches C06F; for peat C10F; for sugar C13B45/00; for textile materials D06H; civil engineering, building, mining, see Section E; for light guides G02B6/25; cutting processed photographic material G03D15/04) - B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00) - B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract A polarizing film cutting knife includes a body portion extending in a first direction, and a knife portion connected to the body portion. The knife portion includes a first surface and a second surface. The first and second surfaces form a first angle. The first angle is about 21.8 to 22.2 degrees. ## Claims ### Claim 1 A method of manufacturing a polarizing plate comprising: unrolling a polarizing film from a polarizing film roll in a preparing process; forming polarizing plates by cutting the polarizing film using a polarizing film cutting knife in a cutting process; sorting out defective goods among the polarizing plates in a testing process; and stacking the polarizing plates which pass the testing process to form a bunch of the polarizing plates in a packaging process which comprises a grinding process, wherein in the grinding process: cutting planes of the bunch of the polarizing plates are grinded to planarize the cutting planes, and only cutting planes which are in parallel with a polarizer direction of the polarizing film are grinded, wherein the polarizer direction is in parallel with a length direction of the polarizing film; wherein the polarizing film cutting knife comprises a body portion extending in a first direction, and a knife portion connected to the body portion and comprising a first surface and a second surface, the first and second surface forms a first angle, and the first angle is about 21.8 to 22.2 degrees. ### Claim 2 (depends on 1) The method of claim 1, wherein the cutting process comprises a first cutting process and a second cutting process, in the first cutting process, the polarizing film is cut in the length direction of the polarizing film using the polarizing film cutting knife, and in the second cutting process, the polarizing film is cut in a width direction of the polarizing film which is substantially perpendicular to the length direction using the polarizing film cutting knife. ### Claim 3 (depends on 2) The method of claim 2, in the first cutting process, the polarizing film is cut along a long side of an upper polarizing plate for a display panel or a short side of a lower polarizing plate for the display panel, and in the second cutting process, the polarizing film is cut along a short side of the upper polarizing plate for the display panel or a long side of the lower polarizing plate for the display panel. ### Claim 4 (depends on 3) The method of claim 3, wherein the packaging process comprises a housing process, in the housing process, the bunch of the polarizing plates is received in a housing element. ### Claim 5 (depends on 4) The method of claim 4, wherein the grinding process is before the housing process. ### Claim 6 (depends on 5) The method of claim 5, wherein in the grinding process, only cutting planes which are formed in the first cutting process are grinded. ### Claim 7 (depends on 1) The method of claim 1, wherein in the cutting process, the polarizing film cutting knife cuts the polarizing film by pressing the polarizing film in a direction which is substantially perpendicular to the polarizing film. ### Claim 8 (depends on 1) The method of claim 1, wherein the first and second surfaces are symmetric with respect to a direction which is substantially perpendicular to the polarizing film, and the first angle is 22 degrees. ### Claim 9 (depends on 8) The method of claim 8, wherein the knife portion of the polarizing film cutting knife comprises carbon steel, and the polarizing film cutting knife further comprises a coating layer formed on the first and second surfaces of the knife portion, the coating layer comprising polytetrafluoroethylene. ### Claim 10 (depends on 1) The method of claim 1, wherein the polarizing film cutting knife is replaced every 30,000 times of cutting.