# US 7,612,493 B2 · Electron emission device with improved focusing of electron beams > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,612,493 B2 - Document ID: US7612493B2 - Status: Granted - Kind: B2 - Application number: 11/118,305 - Filed: 2005-04-28 - Published: 2005-11-03 - Granted: 2009-11-03 - Earliest claimed: 2004-04-29 - Assignees: Samsung SDI Co., Ltd. - Inventors: Seong-Yeon Hwang - Web page: https://patentgrep.com/patent/US7612493B2 ## CPC - H01J 29/06: Screens for shielding; Masks interposed in the electron stream - H01J 2329/00: Electron emission display panels, e.g. field emission display panels - H01J: ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS (spark-gaps H01T; electric arc lamps H05B31/00; particle accelerators H05H) ## Abstract An electron emission device for focusing the electrons emitted from electron emission regions and uniformly controlling the pixel emission characteristic. The electron emission device includes first and second substrates facing each other, and cathode electrodes having first electrode portions formed on the first substrate along one side thereof, and second electrode portions spaced apart from the first electrode portions at a predetermined distance. Electron emission regions are formed on the second electrode portions. Focusing electrodes fill the gap between the first and the second electrode portions while being extended toward the second substrate with a thickness greater than the thickness of the electron emission regions. Gate electrodes are formed on the cathode electrodes by interposing an insulating layer with openings exposing the electron emission regions. ## Claims ### Claim 1 An electron emission device comprising: a first substrate and a second substrate facing each other; cathode electrodes having first electrode portions on the first substrate and second electrode portions spaced apart from the first electrode portions by a gap, the gap being between opposing faces of the first electrode portions and the second electrode portions; electron emission regions having a thickness in a direction between the first and second substrates and being on the second electrode portions; focusing electrodes having a thickness in the direction between the first and second substrates, the focusing electrodes filling the gap while being extended toward the second substrate with a focusing electrode thickness greater than an electron emission region thickness; and gate electrodes on the cathode electrodes with an insulating layer between the gate electrodes and cathode electrodes, the gate electrodes having gate openings exposing the electron emission regions. ### Claim 2 (depends on 1) The electron emission device of claim 1, wherein the second electrode portions are externally surrounded by the first electrode portions. ### Claim 3 (depends on 1) The electron emission device of claim 1, wherein a pair of the focusing electrodes face each other above and along a side of the electron emission region parallel to the cathode electrodes. ### Claim 4 (depends on 1) The electron emission device of claim 1, wherein the focusing electrodes have a resistivity of 10-10,000,000Ω cm. ### Claim 5 (depends on 1) The electron emission device of claim 1, wherein the entire lateral side of the focusing electrode directed toward the electron emission region and a part of the top surface of the focusing electrode directed toward the gate electrode are exposed to an outside of an insulating layer insulating the gate electrode from the cathode electrode. ### Claim 6 (depends on 1) The electron emission device of claim 1, wherein the electron emission region and the focusing electrode satisfy the following condition: 1.5(t2)≦t1≦5(t2) where t1 indicates the thickness of the focusing electrode, and t2 indicates the thickness of the electron emission region. ### Claim 7 (depends on 1) The electron emission device of claim 1, wherein the electron emission region and the focusing electrode satisfy the following condition: 1.5d≦t≦3d where t indicates the thickness of the focusing electrode, and d indicates the shortest distance between the electron emission region and the focusing electrode. ### Claim 8 (depends on 1) The electron emission device of claim 1, wherein the focusing electrode is surrounded by a protective layer. ### Claim 9 (depends on 1) The electron emission device of claim 1, wherein the electron emission region is formed with at least one material selected from the group consisting of carbon nanotube, graphite, graphite nanofiber, diamond, diamond-like carbon, C60, and silicon nanowire. ### Claim 10 (depends on 1) The electron emission device of claim 1, further comprising at least one anode electrode formed on the second substrate, and phosphor layers on a surface of the anode electrode. ### Claim 11 (depends on 2) The electron emission device of claim 2, wherein the gate electrodes are stripe-patterned in the direction perpendicular to the cathode electrodes. ### Claim 12 (depends on 11) The electron emission device of claim 11, wherein one or more of the second electrode portions are formed at respective crossed regions of the cathode electrodes and the gate electrodes. ### Claim 13 (depends on 11) The electron emission device of claim 11, wherein the second electrode portions are at respective crossed regions of the cathode electrodes and the gate electrodes, and at least one of the electron emission regions is on the respective second electrode portions. ### Claim 14 (depends on 11) The electron emission device of claim 11, wherein a plurality of the second electrode portions are at respective crossed regions of the cathode and the gate electrodes, and one of the electron emission regions is formed on each of the respective second electrode portions. ### Claim 15 (depends on 3) The electron emission device of claim 3, wherein the focusing electrodes are stripe-patterned in the longitudinal direction of the cathode electrodes. ### Claim 16 (depends on 8) The electron emission device of claim 8, wherein the protective layer is chromium. ### Claim 17 A method of focusing electrons emitted from electron emission regions in an electron emission device to corresponding light emitting regions, the electron emission regions being on cathode electrodes on a first substrate, the corresponding light emitting regions being on a second substrate separated from the first substrate, the method comprising: forming gate electrodes over the cathodes electrodes, the gate electrodes being separated from the cathode electrodes by an insulating layer and having gate openings exposing respective electron emission regions at crossings of the gate electrodes and the cathode electrodes; wherein the cathode electrodes have an internal cathode region within respective gate openings and support at least one electron emission region and are separated from an external cathode region by focusing electrodes parallel to the cathode electrodes, the focusing electrodes filling a gap between opposing faces of the internal cathode region and the external cathode region. ### Claim 18 (depends on 17) The method of claim 17, wherein the focusing electrodes and the electron emission regions each have a thickness in the direction between the first substrate and second electrodes, such that a focusing electrode thickness is greater than an electron emission region thickness. ### Claim 19 (depends on 18) The method of claim 18, wherein respective electron emission regions and focusing electrodes satisfy the following condition: 1.5(t2)≦t1≦5(t2) where t1 indicates the thickness of the focusing electrode, and t2 indicates the thickness of the electron emission region. ### Claim 20 (depends on 18) The method of claim 18, wherein respective electron emission regions and focusing electrodes satisfy the following condition: 1.5d≦t≦3d where t indicates the thickness of the focusing electrode, and d indicates the shortest distance between a respective electron emission region and focusing electrode.