# US 7,411,357 B2 · Liquid crystal and device of driving light source therefor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,411,357 B2 - Document ID: US7411357B2 - Status: Granted - Kind: B2 - Application number: 11/003,622 - Filed: 2004-12-03 - Published: 2005-07-07 - Granted: 2008-08-12 - Earliest claimed: 2003-12-04 - Assignees: Samsung Electronics Co., Ltd. - Inventors: Sang-Yong Lee - Web page: https://patentgrep.com/patent/US7411357B2 ## CPC - H05B 41/2822: {using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations} - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A device of driving a plurality of lamps is provided, which includes: a transforming unit supplying driving voltages having inverted phases to adjacent lamps; and an inverter controlling the transforming unit. ## Claims ### Claim 1 A device for driving a plurality of lamps, the device comprising: a transforming unit which has at least two transformers and supplies driving voltages having inverted phases to adjacent lamps; and an inverter which controls the transforming unit, wherein each of the lamps comprise an external electrode fluorescent lamp (EEFL), each of the transformers has a primary coil connected to the inverter and a secondary coil connected to the lamps, and two terminals of the secondary coil are connected to different lamps. ### Claim 2 (depends on 1) The device of claim 1, wherein the inverter supplies voltages having inverted phases to the first and the second transformers. ### Claim 3 (depends on 1) The device of claim 1, wherein the primary coils of the first and the second transformers are connected to each other via a capacitor. ### Claim 4 (depends on 1) The device of claim 1, further comprising a luminance sensor which detects a luminance of the lamps and which provides luminance information for the inverter. ### Claim 5 A device for driving a plurality of lamps, the device comprising: a transforming unit which has at least four transformers and supplies driving voltages having inverted phases to adjacent lamps; and an inverter which controls the transforming unit, wherein each of the lamps comprise external electrode fluorescent lamp (EEFL), each of the transformers has a primary coil connected to the inverter and a secondary coil connected to the lamps, a lamp is connected to two different secondary coils and wherein a first two primary coils corresponding to two secondary coils connected to the first lamp and a second two primary coils corresponding to two secondary coils connected to the second lamp are connected to the inverter in parallel. ### Claim 6 (depends on 5) The device of claim 5, wherein the at least four transformers comprise: a first transformer including a primary coil connected to the inverter and a secondary coil connected to a first lamp; a second transformer including a primary coil connected to the inverter and a secondary coil connected to a second lamp; a third transformer including a primary coil connected to the inverter and a secondary coil connected to the first lamp; and a fourth transformer including a primary coil connected to the inverter and a secondary coil connected to the second lamp, wherein the secondary coils of the first to the fourth transformers are connected to a ground via resistors. ### Claim 7 (depends on 6) The device of claim 6, wherein the primary coils of the first and the third transformers are connected to each other via a first capacitor and the primary coils of the second and the fourth transformers are connected to each other via a second capacitor. ### Claim 8 (depends on 5) The device of claim 5, further comprising a current sensor which detects a current flowing in the transforming unit and which provides current information for the inverter. ### Claim 9 (depends on 8) The device of claim 8, wherein the current sensor comprises a plurality of first to fourth resistors. ### Claim 10 (depends on 9) The device of claim 9, wherein the transforming unit comprises: a first transformer including a primary coil connected to the inverter and a secondary coil having a first terminal connected to a first lamp and a second terminal connected to the first resistor; a second transformer including a primary coil connected to the inverter and a secondary coil having a first terminal connected to the first lamp and a second terminal connected to the second resistor; a third transformer including a primary coil connected to the inverter and a secondary coil having a first terminal connected to a second lamp and a second terminal connected to the third resistor; a fourth transformer including a primary coil connected to the inverter and a secondary coil having a first terminal connected to the second lamp and a second terminal connected to the fourth resistor; a first capacitor connected to the primary coils of the first and the second transformers; and a second capacitor connected to the primary coils of the third and the fourth transformers. ### Claim 11 (depends on 9) The device of claim 9, wherein the first to the fourth resistors have grounded terminals. ### Claim 12 A liquid crystal display, comprising: a plurality of pixels arranged in a matrix; a plurality of lamps, which supplies light to the pixels based on driving voltages, and comprises a first lamp and a second lamp; a transforming unit which has at least four transformers and supplies the driving voltages having inverted phases to adjacent lamps; an inverter which controls the transforming unit; and a current sensor which detects a current which flows in the transforming unit and which provides current information for the inverter, wherein each of the lamps comprise an external electrode fluorescent lamp (EEFL), each of the transformers has a primary coil connected to the inverter and a secondary coil connected to the lamps, a lamp is connected to two different secondary coils and wherein a first two primary coils corresponding to two secondary coils connected to the second lamp are connected to the inverter in parallel. ### Claim 13 A liquid crystal display, comprising: a plurality of pixels arranged in a matrix; a plurality of lamps which supplies light to the pixels based on driving voltages; a transforming unit which has at least two transformers and which supplies the driving voltages having inverted phases to adjacent lamps; an inverter which controls the transforming unit; and a luminance sensor which detects a luminance of the lamps and which provides luminance information for the inverter, wherein each of the lamps comprise an external electrode fluorescent lamp (EEFL), each of the transformers has a primary coil connected to the inverter and a secondary coil connected to the lamps, and two terminals of the secondary coil are connected to different lamps. ### Claim 14 (depends on 13) The liquid crystal display of claim 13, wherein the luminance sensor is disposed opposite the pixels with respect to the lamps. ### Claim 15 (depends on 14) The liquid crystal display of claim 14, wherein the luminance sensor are disposed near a center of the lamps.