# US 10,871,666 B2 · Display device comprising a viewing angle switching element having a first linear polarizer, an optically anisotropic layer, a viewing angle control cell, and a second linear polarizer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,871,666 B2 - Document ID: US10871666B2 - Status: Granted - Kind: B2 - Application number: 16/880,997 - Filed: 2020-05-22 - Published: 2020-09-10 - Granted: 2020-12-22 - Earliest claimed: 2017-11-27 - Assignees: FUJIFILM Corporation - Applicants: Fujifilm Corporation - Inventors: Yukito Saitoh; Hiroshi Sato; Naoyoshi Yamada - Web page: https://patentgrep.com/patent/US10871666B2 ## CPC - G02F 1/1323: {Arrangements for providing a switchable viewing angle} - G02F 1/13: based on liquid crystals, e.g. single liquid crystal display cells - G02F 1/1335: Structural association of cells with optical devices, e.g. polarisers or reflectors - G02F 1/133528: {Polarisers} - G02F 1/13363: Birefringent elements, e.g. for optical compensation - G02F 1/1337: Surface-induced orientation of the liquid crystal molecules, e.g. by alignment layers - G02F 1/1347: Arrangement of liquid crystal layers or cells in which the final condition of one light beam is achieved by the addition of the effects of two or more layers or cells - G02F 1/13471: {in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells (G02F1/13475 takes precedence)} - G09F 9/00: Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements (in which the variable information is permanently attached to a movable support G09F11/00; abacus G06C1/00; slide-rules G06G1/00) - G02F 1/133638: {Waveplates, i.e. plates with a retardation value of lambda/n} - 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 - G09F: DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS ## Abstract A display device includes an image display panel, and a viewing angle switching element includes a first linear polarizer, an optically anisotropic layer, a viewing angle control cell, and a second linear polarizer, in which an angle formed between transmission axes of the first linear polarizer and the second linear polarizer is 45°, the optically anisotropic layer has a function of changing an azimuth of a polarization axis of linearly polarized light emitted from the first linear polarizer and causing the light to be emitted toward the viewing angle control cell, the viewing angle control cell is formed of a vertically aligned liquid crystal cell in which vertically aligned liquid crystals are tilted in one direction by voltage application, and an angle formed between a tilt azimuth of the vertically aligned liquid crystal of the viewing angle control cell and the transmission axis of the second linear polarizer is 45°. ## Claims ### Claim 1 A display device comprising: an image display panel; and a viewing angle switching element that is arranged on a display surface side of the image display panel and changes a viewing angle, wherein the viewing angle switching element includes a first linear polarizer, an optically anisotropic layer, a viewing angle control cell, and a second linear polarizer arranged in order from an image display panel side, an angle formed between transmission axes of the first linear polarizer and the second linear polarizer is 45°, the optically anisotropic layer has a function of changing an azimuth of a polarization axis of linearly polarized light emitted from the first linear polarizer to an azimuth forming an angle of 45° with the azimuth of the polarization axis and causing the light to be emitted toward the viewing angle control cell, and the viewing angle control cell is formed of a vertically aligned liquid crystal cell in which vertically aligned liquid crystals are tilted in one direction by voltage application, and an angle formed between a tilt azimuth of the vertically aligned liquid crystal of the viewing angle control cell and the transmission axis of the second linear polarizer is 45°. ### Claim 2 (depends on 1) The display device according to claim 1, wherein the optically anisotropic layer changes the polarization axis of linearly polarized light emitted from the first linear polarizer to an azimuth orthogonal to the transmission axis of the second linear polarizer to cause emit the light to be emitted toward the viewing angle control cell, and the viewing angle switching element changes the viewing angle in the tilt azimuth of the vertically aligned liquid crystal of the viewing angle control cell. ### Claim 3 (depends on 2) The display device according to claim 2, wherein the viewing angle is changed by switching an alignment state of the vertically aligned liquid crystal of the vertically aligned liquid crystal cell between an oblique alignment in which the liquid crystal is obliquely tilted in the tilt azimuth and a horizontal alignment with a polar angle of 90°. ### Claim 4 (depends on 1) The display device according to claim 1, wherein the optically anisotropic layer changes the polarization axis of linearly polarized light emitted from the first linear polarizer to an azimuth parallel to the transmission axis of the second linear polarizer to cause the light to be emitted toward the viewing angle control cell, and the viewing angle switching element changes the viewing angle in an azimuth that forms 180° with the tilt azimuth of the vertically aligned liquid crystal of the viewing angle control cell. ### Claim 5 (depends on 4) The display device according to claim 4, wherein the viewing angle is changed by switching an alignment state of the vertically aligned liquid crystal of the vertically aligned liquid crystal cell between a vertical alignment with a polar angle of 0° and an oblique alignment in which the liquid crystal is obliquely tilted in the tilt azimuth. ### Claim 6 (depends on 1) The display device according to claim 1, wherein the optically anisotropic layer is a λ/2 plate. ### Claim 7 (depends on 1) The display device according to claim 1, wherein the optically anisotropic layer is a film that rotates the polarization axis of the linearly polarized light emitted from the first linear polarizer by 45° to cause the light to be emitted toward the viewing angle control cell. ### Claim 8 (depends on 1) The display device according to claim 1, wherein the image display panel includes a liquid crystal cell for display, and two linear polarizers that are arranged to face to each other with the liquid crystal cell for display interposed therebetween, and one of the two linear polarizers functions as the first linear polarizer of the viewing angle switching element.