# US 12,222,526 B2 · Mid-air image display device and method of operating the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,526 B2 - Document ID: US12222526B2 - Status: Granted - Kind: B2 - Application number: 17/543,356 - Filed: 2021-12-06 - Published: 2022-06-09 - Granted: 2025-02-11 - Earliest claimed: 2020-12-04 - Assignees: Samsung Electronics Co., Ltd. - Applicants: Samsung Electronics Co., Ltd. - Inventors: Vladimir Nikolayevich Borisov; Svetlana Vladimirovna Danilova; Ilia Valer'evich Malyshev; Nikolay Victorovich Muravev; Mikhail Vyacheslavovich Popov; Stanislav Aleksandrovich Shtykov; Alexander Alekseyevich Aspidov - Web page: https://patentgrep.com/patent/US12222526B2 ## CPC - G02B 30/56: by projecting aerial or floating images - G02B 27/106: {for splitting or combining a plurality of identical beams or images, e.g. image replication} - G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS ## Abstract A mid-air image display device and an operation method thereof are provided. The mid-air image display device includes: a projection system configured to generate a light beam for an image; at least one positive lens; and a light multiplication module comprising a first transmission grating, a second transmission grating, a waveguide and a reflection grating, and configured to receive the light beam from the projection system and transmit the received light beam through the first transmission grating, the second transmission grating, the waveguide and the reflection grating, wherein the at least one positive lens is disposed on the light multiplication module, and configured to receive the light beam transmitted through the light multiplication module to form a mid-air image. ## Claims ### Claim 1 A mid-air image display device comprising: a projection system configured to output a light beam for an image; at least one positive lens; and a light multiplication module comprising a first transmission grating, a second transmission grating, a waveguide and a reflection grating, and configured to receive the light beam from the projection system and transmit the received light beam through the first transmission grating, the second transmission grating, the waveguide and the reflection grating, wherein the at least one positive lens is disposed on the light multiplication module, and configured to receive the light beam transmitted through the light multiplication module to form a mid-air image. ### Claim 2 (depends on 1) The display device of claim 1, wherein the projection system is disposed above the at least one positive lens, wherein the at least one positive lens is disposed above the waveguide of the light multiplication module, and wherein the first transmission grating, the reflection grating, and the second transmission grating are sequentially arranged below the waveguide. ### Claim 3 (depends on 1) The display device of claim 1, wherein the projection system is disposed below the at least one positive lens, wherein the at least one positive lens is disposed below the waveguide, and wherein the first transmission grating, the second transmission grating, and the reflection grating are sequentially arranged above the waveguide. ### Claim 4 (depends on 1) The display device of claim 1, wherein the projection system is disposed above the at least one positive lens that is disposed above the light multiplication module, wherein the waveguide is disposed below the first transmission grating, and wherein the second transmission grating and the reflection grating are arranged below the waveguide. ### Claim 5 (depends on 1) The display device of claim 1, wherein the at least one positive lens is disposed below the reflection grating of the light multiplication module, wherein the first transmission grating, the second transmission grating, and the waveguide are disposed above the reflection grating, and wherein the light multiplication module is disposed below the projection system. ### Claim 6 (depends on 1) The display device of claim 1, wherein the at least one positive lens is disposed above the reflection grating of the light multiplication module, wherein the second transmission grating, the first transmission grating, and the waveguide are sequentially arranged below the reflection grating, and wherein the projection system is disposed below the light multiplication module. ### Claim 7 (depends on 1) The display device of claim 1, wherein the at least one positive lens is disposed below the reflection grating of the light multiplication module, wherein the second transmission grating, the waveguide, and the first transmission grating are sequentially disposed above the reflection grating, and wherein the projection system is disposed above the light multiplication module. ### Claim 8 (depends on 1) The display device of claim 1, wherein the waveguide comprises a sector of a total internal reflection-based light transmission diffraction multi-radial directional waveguide. ### Claim 9 (depends on 8) The display device of claim 8, wherein the light multiplication module further comprises a prism for in-coupling of light. ### Claim 10 (depends on 8) The display device of claim 8, wherein one of anti-reflective coating, semi-reflective coating, a dichroic filter, a neutral filter, and a diffraction optical element is provided on a surface of the waveguide. ### Claim 11 (depends on 8) The display device of claim 8, wherein the first transmission grating, the second transmission grating, and the reflection grating are recorded on a film, and are a volume holographic grating deposited on a surface of the waveguide or a relief diffraction element formed on a surface of the waveguide. ### Claim 12 (depends on 11) The display device of claim 11, wherein the light multiplication module has a shape of one disc sector, and wherein the light multiplication module forms a disc shape as a whole. ### Claim 13 (depends on 12) The display device of claim 12, wherein each of the at least one positive lens has a shape of one disc sector, wherein a radius of the disk sector matches a radius of the light multiplication module, and wherein a corresponding one of the at least one positive lens is disposed on the light multiplication module. ### Claim 14 (depends on 13) The display device of claim 13, wherein the at least one positive lens forms a circular lens array as a whole. ### Claim 15 A method of operating a mid-air image display device comprising a projection system, a positive lens, and a light multiplication module comprising a first transmission grating, a second transmission grating, a waveguide, and a reflection grating, the positive lens being disposed on the light multiplication module, the method comprising: transmitting a beam forming an image from the projection system to the first transmission grating, the beam, as a result of diffraction at the first transmission grating, being split into a 1st order diffraction beam and a 0th order diffraction beam of the first transmission grating; transmitting the 0th order diffraction beam of the first transmission grating to the second transmission grating, the 0th order diffraction beam of the first transmission grating, as a result of diffraction at the second transmission grating, being split into a 1st order diffraction beam and a 0th order diffraction beam of the second transmission grating; transmitting the 1st order diffraction beams of the first and second transmission gratings and the 0th order diffraction beam of the second transmission grating to the waveguide; allowing the 1st order diffraction beams of the first and second transmission gratings transmitted to the waveguide at an angle corresponding to a total internal reflection angle range to be reflected at an interface between air and the first transmission grating and an interface between the waveguide and the reflection grating, thereby to propagate along the waveguide to form another 1st order diffraction beam at the second transmission grating as a result of diffraction of the 1st order diffraction beam of the first transmission grating at the waveguide, and to form another 1st order diffraction beam at the first transmission grating as a result of diffraction of the 1st order diffraction beam of the second transmission grating at the waveguide; diffracting, by the reflection grating, the other 1st order diffraction beam of the second transmission grating and the other 1st order diffraction beam of the first transmission grating to be out-coupled to the positive lens through the waveguide, the second transmission grating, and the first transmission grating; and refracting the out-coupled beams and focusing a mid-air image on a focal plane, by the positive lens. ### Claim 16 (depends on 15) The method of claim 15, wherein the 0th order diffraction beam of the second transmission grating passes through the waveguide above the reflection grating, the 0th order beam of the second transmission grating is split into a 1st order diffraction beam and a 0th order diffraction beam of the reflection grating, and then the 0th order diffraction beam of the reflection grating is not considered. ### Claim 17 (depends on 15) The method of claim 15, wherein the 1st order diffraction beam of the reflection grating passes through the waveguide, the second transmission grating, and the first transmission grating, and reflected back to the waveguide due to total internal reflection in a surface of the first transmission grating, and wherein the 1st order diffraction beam of the reflection grating is transmitted to the first transmission grating, and, as a result of diffraction at the first transmission grating, is split into still another 1st order diffraction beam and another 0th order the diffraction beam of the first transmission grating. ### Claim 18 (depends on 15) The method of claim 15, wherein the light multiplication module is configured to allow the mid-air image to be viewed only within a range perpendicular to the mid-air image display device. ### Claim 19 (depends on 15) The method of claim 15, wherein the light multiplication module is configured to allow the mid-air image to be viewed both in a range perpendicular to the mid-air image display device and in a range deviated from the range perpendicular to the mid-air image display device. ### Claim 20 A mid-air image display device comprising: a projection system configured to output a light beam for an image; a second positive lens disposed below the projection system; a light multiplication module configured to receive the light beam output from the projection system; a first positive lens and a second positive lens disposed below and above the light multiplication module, respectively, and configured to receive the light beam transmitted through the light multiplication module to form a mid-air image, wherein the light multiplication module comprises: a reflection grating disposed above the first positive lens; a waveguide disposed above the reflection grating; a second transmission grating disposed above the waveguide; a first transmission grating disposed above the second transmission grating and below the second positive lens.