Inverter circuit, fluorescent bulb operating device, backlight device, and liquid crystal display device

• US 20060120109A1
• Filed: 07/04/2003
• Published: 06/08/2006
• Est. Priority Date: 08/06/2002
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Shimizu, Masaki, Ohtani, Shuhki, Inoue, Yutaka
• Granted Patent: US 7,777,431 B2
• Time in Patent Office: Days
• US Class Current: 362/614
• CPC Class Codes: G09G 3/3406 Control of illumination source illumination devices structurally associated with liquid crystal cells G02F1/1336
• CPC Class Codes: H05B 41/2821 by means of a single-switch converter or a parallel push-pull converter in the final stage H05B41/285 takes precedence
• CPC Class Codes: H05B 41/2822 using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps

Abstract

A driving apparatus and a driving method are disclosed that are capable of uniformly lighting each entire fluorescent tube irrespective of the length or number of fluorescent tubes when simultaneously driving a plurality of fluorescent tubes in a fluorescent tube lighting apparatus. When two inverter circuits having respective transformers are provided at both ends of a fluorescent tube to light the fluorescent tube by push-pull driving, feedback windings of transformers not used in self-excited oscillation of each inverter circuit are connected together, with the transformer connection that connects together the feedback windings being either in-phase or in opposite phase, and the method of connection for fluorescent tubes connecting to secondary windings of each transformer can be changed in accordance with that connection method.

Claims

1-49. -49. (canceled)

50. A backlight apparatus comprising:

a plurality of fluorescent tubes arranged in parallel in a substantially identical longitudinal direction; and

a plurality of fluorescent tube lighting devices each comprising a pair of inverter circuits for applying voltages having opposite phases to both ends of each fluorescent tube to drive the fluorescent tube, wherein

each of the pair of inverter circuits in each fluorescent tube lighting device is formed on a separate substrate, and wherein

each of the pair of inverter circuits is disposed in the vicinity of both ends of the arranged fluorescent tubes such that the fluorescent tube lighting devices can drive the fluorescent tubes.

51. The backlight apparatus according to claim 50, wherein

the pair of inverter circuits is capable of driving n (an integer not less than 2) fluorescent tubes, and

the fluorescent tube lighting device drives n fluorescent tubes arranged in parallel simultaneously.

52. The backlight apparatus according to claim 50 or 51, wherein

at least one group of inverter circuits is disposed at one end of the plurality of fluorescent tubes arranged in parallel, said inverter circuits being disposed adjacent to one another in the direction in which the fluorescent tubes are arranged, wherein said inverter circuits are connected to be operated synchronously.

53. A liquid crystal display apparatus comprising the backlight apparatus according to claim 50 and a liquid crystal panel.

54. A driving apparatus comprising a pair of inverter circuits each comprising an inverter transformer that is formed by one primary winding, n (an integer not less than 2) secondary windings, and at least one tertiary winding, the pair of inverter circuits being connected to both ends of n driven units for driving the same, wherein

the secondary windings in one inverter circuit are connected to one end of each of the n driven units,

the n secondary windings in the other inverter circuit are connected to the other end of each of the n driven units, and

one of the tertiary windings in one inverter circuit and one of the tertiary windings in the other inverter circuit are connected to be operated synchronously.

55. The driving apparatus according to claim 54, wherein

the number of the secondary windings is two and the number of the driven units is two, and

in each of the pair of the inverter circuits, the two secondary windings of the inverter transformer each has an opposite winding with respect to each other.

56. The driving apparatus according to claim 54, wherein

in the pair of the inverter circuits, the primary winding of the inverter transformer in one inverter circuit and the primary winding of the inverter transformer in the other inverter circuit have opposite windings with respect to each other.

57. A backlight apparatus comprising the driving apparatus according to claim 54, wherein the driven unit is a fluorescent tube.

58. A liquid crystal display apparatus comprising the backlight apparatus according to claim 57 and a liquid crystal panel.

59. A backlight apparatus comprising:

a plurality of the driving apparatus according to claim 54;

wherein the n driven units are n fluorescent tubes, wherein

the n fluorescent tubes are arranged in parallel such that the longitudinal directions thereof are substantially the same,

at least one group of the inverter circuits connected at the same end of the fluorescent tubes arranged in parallel is connected synchronously.

60. A liquid crystal display apparatus comprising the backlight apparatus according to claim 59 and a liquid crystal panel.

61. A driving apparatus comprising a pair of inverter circuits each comprising an inverter transformer that is formed by a primary winding, a secondary winding, and a tertiary winding used in self-excited oscillation, the pair of inverter circuits being connected to both ends of a driven unit for driving the driven unit, wherein

the pair of inverter circuits is connected using the inductive coupling effect.

62. The driving apparatus according to claim 61, wherein

two one-input one-output inverter transformers are mounted on the inverter circuits, respectively.

63. The driving apparatus according to claim 61, wherein

the primary windings of the two inverter transformer have an opposite winding with respect to each other.

64. The driving apparatus according to claim 61, wherein

the pair of inverter circuits are connected to both ends of the driven unit such that they have an opposite phase relationship with respect to each other.

65. A backlight apparatus comprising the driving apparatus according to claim 61, wherein

the driven unit is a fluorescent tube, and the driving apparatus drives the fluorescent tube.

66. A liquid crystal display apparatus comprising a liquid crystal panel, and the backlight apparatus according to claim 65.

67. A driving apparatus comprising a pair of inverter circuits connected to both ends of a driven unit, wherein

both ends of the driven unit are connected via a secondary winding of an inverter transformer having a tertiary winding used in self-excited oscillation in one inverter circuit, and via a secondary winding of an inverter transformer having a tertiary winding not used in self-excited oscillation in the other inverter circuit.

69. A backlight apparatus comprising the driving apparatus according to claim 67, wherein

the driven unit is a fluorescent tube, and the driving apparatus drives the fluorescent tube.

70. A liquid crystal display apparatus comprising a liquid crystal panel, and the backlight apparatus according to claim 69.

68. The driving apparatus according to claim wherein

the pair of inverter circuits are connected to both ends of the driven unit such that they have an opposite phase relationship with respect to each other.

71. A driving apparatus comprising a pair of inverter circuits connected to both ends of a driven unit, wherein

the pair of inverter circuits is connected using the coupling between choke coils or the coupling between windings connected in parallel to tertiary windings used in self-excited oscillation.

72. The driving apparatus according to claim 71, wherein

the pair of inverter circuits are connected to both ends of the driven unit such that they have an opposite phase relationship with respect to each other.

73. A backlight apparatus comprising the driving apparatus according to claim 71, wherein

the driven unit is a fluorescent tube, and the driving apparatus drives the fluorescent tube.

74. A liquid crystal display apparatus comprising a liquid crystal panel, and the backlight apparatus according to claim 73.

75. A driving apparatus comprising a pair of inverter circuits each having a plurality of inverter transformers including a primary winding and a high-order winding and a self-excited oscillation circuit for convening a direct current inputted to the primary winding to an alternating current, the pair of inverter circuits being connected to both ends of a driven unit for driving the driven units, wherein

in each inverter circuit, at least one of the plurality of inverter transformers has a plurality of high-order windings, wherein

one of the high-order windings of the inverter transformer having the plurality of high-order windings is connected to the self-excited oscillation circuit and one of other high-order windings is connected to a driven unit, wherein

a high-order winding of the inverter transformer that does not have such a high-order winding of an inverter transformer that is connected to the self-excited oscillation circuit in one inverter circuit and a high-order winding of the inverter transformer that does not have such a high-order winding of an inverter transformer that is connected to the self-excited oscillation circuit in the other inverter circuit are connected.

76. The driving apparatus according to claim 75, wherein

the pair of inverter circuits are connected to both ends of the driven unit such that they have an opposite phase relationship with respect to each other.

77. A backlight apparatus comprising the driving apparatus according to claim 75, wherein

the driven unit is a fluorescent tube, and the driving apparatus drives the fluorescent tube

78. A liquid crystal display apparatus comprising a liquid crystal panel, and the backlight apparatus according to claim 77.

79. A driving apparatus comprising a pair of inverter circuits having an inverter transformer including at least one secondary winding and a plurality of feedback windings relative to a primary winding and a self-excited oscillation circuit for converting a direct current inputted to the primary winding to an alternating current, the pair of inverter circuits being connected to both ends of a driven unit for driving the driven units, wherein

in each inverter circuit, at least one of the feedback windings among the feedback windings in the inverter transformer circuit and the self-excited oscillation circuit are connected, wherein

at least one of the feedback windings among those feedback windings of the inverter transformer that are not connected to the self-excited oscillation circuit in one inverter circuit and at least one of the feedback windings among those feedback windings of the inverter transformer that are not connected to the self-excited oscillation circuit in the other inverter circuit are connected.

80. The driving apparatus according to claim 79, wherein

the pair of inverter circuits are connected to both ends of the driven unit such that they have an opposite phase relationship with respect to each other.

81. A backlight apparatus comprising the driving apparatus according to claim 79, wherein

the driven unit is a fluorescent tube, and the driving apparatus drives the fluorescent tube.

82. A liquid crystal display apparatus comprising a liquid crystal panel, and the backlight apparatus according to claim 81.

83. A backlight apparatus comprising:

a long tubular fluorescent tube; and

a pair of inverter transformers for converting input voltage into high voltage and for supplying high voltage having opposite phases to both ends of the fluorescent tube, wherein,

the pair of inverter transformers is respectively disposed in the vicinity of both ends of the fluorescent tube for supplying high voltage to the fluorescent tube.

84. The backlight apparatus according to claim 83, comprising:

a plurality of the fluorescent tubes disposed in parallel such that the longitudinal directions thereof are substantially the same; and

a plurality of the pairs of the inverter transformers, wherein a high voltage having opposite phases is supplied to both ends of each of the plurality of fluorescent tubes.

85. The backlight apparatus according to claim 83, comprising:

a plurality of the fluorescent tubes, wherein the plurality of fluorescent tubes is disposed in parallel such that the longitudinal directions thereof are substantially the same, wherein,

each of the plurality of inverter transformers includes a plurality of secondary windings for outputting high voltage, and wherein,

the same ends of adjacently disposed fluorescent tubes of the plurality of fluorescent tubes are connected to the plurality of secondary windings of one of the pair of inverter transformers.

86. A liquid crystal display comprising the backlight apparatus according to claim 83 and a liquid crystal panel.