JP2007095353A - Discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device in which a magnetic field generated by a plurality of electromagnetic transformers can be controlled. <P>SOLUTION: The discharge lamp lighting device 1 is provided with a plurality of electromagnetic transformers which are positioned corresponding to a plurality of discharge lamps 3, respectively, and have secondary winding wires 5c connected with the discharge lamps 3 and have primary winding wires 5b having the same winding direction with the secondary winding wires 5c, and a current direction setting circuit 11 which is connected with each of the primary winding wires 5b of these electromagnetic transformers 5 and set a direction, alternately in reversal, of a current which is passed to each of the primary winding wires 5b of the plurality of electromagnetic transformers 5. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device.

  The discharge lamp lighting device is used, for example, as a direct type backlight device for a liquid crystal display device used for a portable information terminal, a computer, a television, and the like. As such a discharge lamp lighting device, the discharge lamp lighting suppresses the influence (electric field noise) on the display device due to the electric field generated on the high voltage side by inverting the phase of the voltage waveform applied to the plurality of discharge lamps for each discharge lamp. A device has been proposed. There has also been proposed a discharge lamp lighting device that suppresses the influence (magnetic field noise) of a magnetic field caused by a discharge lamp or a connection line (see, for example, Patent Document 1).

  As shown in FIG. 7, the phase inversion type discharge lamp lighting device 101 includes a plurality of discharge lamps 102 connected in series every two, and a plurality of electromagnetic transformers 103 respectively connected to the respective discharge lamps 102. ing. Each electromagnetic transformer 103 is connected to a high frequency power source 104.

  The electromagnetic transformer 103 includes a core 103a serving as a magnetic core, and a primary winding 103b and a secondary winding 103c wound around the core 103a. The terminal S101 of the primary winding 103b of each electromagnetic transformer 103 is connected to the power supply terminal D101 of the high frequency power supply 104, and the terminal S102 of the primary winding 103b of each electromagnetic transformer 103 is connected to the power supply terminal D102 of the high frequency power supply 104. Each is connected. The high voltage terminal of the secondary winding 103c of the electromagnetic transformer 103 is connected to the high voltage side electrode of the discharge lamp 3, and the low voltage terminal of the secondary winding 103c of the electromagnetic transformer 103 is grounded. In two adjacent electromagnetic transformers 103, the winding directions of the respective primary windings 103b are the same, and the winding directions of the respective secondary windings 103c are reversed (in FIG. 7). See arrow).

  In the discharge lamp lighting device 101 having such a configuration, when a current is supplied from the high-frequency power source 104 to the primary winding 103b of each electromagnetic transformer 103, the primary winding 103b of each electromagnetic transformer 103 is directed in the same direction. Current flows. At this time, since the winding directions of the secondary windings 103c of the two adjacent electromagnetic transformers 103 are reversed, a current flows in the reverse direction in the secondary winding 103c of each electromagnetic transformer 103. Thereby, each voltage waveform applied to the two adjacent discharge lamps 102 is phase-inverted, and the influence on the display device due to the electric field generated on the high voltage side is suppressed.

Further, the directions of the magnetic fields generated by the secondary windings 103c of the two adjacent electromagnetic transformers 103 are different and cancel each other, so that the magnetic field generated on the high voltage side is suppressed. On the other hand, the primary winding 103b of each of the two adjacent electromagnetic transformers 103 has the same winding direction, and the direction of the magnetic field generated by each of the primary windings 103b is the same. The magnetic field is not suppressed. Since the magnetic field generated on the low voltage side is very weak, it does not have a great influence on the display device.
JP 2000-30879 A

  However, with the recent increase in the screen size of display devices, the length of the discharge lamp 102 has become longer, and the voltage required for the good lighting of the discharge lamp 102 has increased. The influence of the magnetic field generated on the side has also become prominent. For example, beat noise (striped pattern) or the like is generated in the display device due to the magnetic field generated on the low voltage side.

  The present invention has been made in view of the above, and an object of the present invention is to provide a discharge lamp lighting device capable of suppressing a magnetic field generated by a plurality of electromagnetic transformers.

  A first feature according to an embodiment of the present invention is that, in a discharge lamp lighting device, a secondary winding provided corresponding to each of a plurality of discharge lamps and connected to the discharge lamp is the same as the secondary winding. A plurality of electromagnetic transformers each having a primary winding in a winding direction and a primary winding of each of the plurality of electromagnetic transformers are provided to be passed through each primary winding of the plurality of electromagnetic transformers. And a current direction setting circuit for sequentially reversing and setting the direction of current for each electromagnetic transformer.

  In the first feature according to the embodiment of the present invention, by providing a current direction setting circuit that inverts and sets the direction of the current flowing through the primary winding of each of the plurality of electromagnetic transformers for each electromagnetic transformer, The directions of the magnetic fields generated by the adjacent electromagnetic transformers are reversed, and these magnetic fields cancel each other.

  The second feature according to the embodiment of the present invention is that, in the discharge lamp lighting device, the secondary winding provided corresponding to each of the plurality of discharge lamps and connected to the discharge lamp is the same as the secondary winding. A plurality of electromagnetic transformers each having a primary winding in a winding direction; and a plurality of electromagnetic transformers connected to the primary windings of each of the plurality of electromagnetic transformers, and dividing the plurality of electromagnetic transformers into a plurality of transformer groups; And a current direction setting circuit that reverses and sets the direction of the current flowing through the primary winding of each of the plurality of electromagnetic transformers for each transformer group.

  In the second feature according to the embodiment of the present invention, there is provided a current direction setting circuit for sequentially reversing and setting the direction of the current flowing through the primary winding of each of the plurality of electromagnetic transformers for each of the plurality of transformer groups. Thus, the directions of the magnetic fields generated by adjacent transformer groups are reversed, and these magnetic fields cancel each other.

  ADVANTAGE OF THE INVENTION According to this invention, the discharge lamp lighting device which can suppress the magnetic field which generate | occur | produces with a some electromagnetic transformer can be provided.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, the discharge lamp lighting device 1 according to the first embodiment of the present invention includes a main body case 2, a plurality of discharge lamps 3 provided inside the main body case 2, and a main body. Inverter board 4 provided on the outer surface of case 2, a plurality of electromagnetic transformers 5 provided on inverter board 4 and connected to each discharge lamp 3, and light from each discharge lamp 3 provided in main body case 2 And a diffusion plate 6 to be diffused. For example, a display panel such as a liquid crystal panel is provided on the outer surface of the diffusion plate 6.

  As shown in FIG. 3, each discharge lamp 3 is connected to a high-frequency power source 12 via each electromagnetic transformer 5 and a current direction setting circuit 11 that sets the direction of a current flowing through the electromagnetic transformer 5. Each discharge lamp 3 is connected in series every two. The high voltage side electrode of each discharge lamp 3 is connected to each electromagnetic transformer 5, and the low voltage side electrode of each discharge lamp 3 is grounded. For example, a cold cathode discharge lamp is used as the discharge lamp 3.

  The electromagnetic transformer 5 includes a core 5a serving as a magnetic core, a primary winding 5b wound around the core 5a, and a secondary winding 5c wound around the core 5a. The winding directions of the primary winding 5b and the secondary winding 5c are the same (direction of arrow in FIG. 3), and the number of turns of the secondary winding 5c is larger than the number of turns of the primary winding 5b. Thereby, the electromagnetic transformer 5 becomes a step-up transformer. The high voltage terminal of the secondary winding 5c of the electromagnetic transformer 5 is connected to the high voltage side electrode of the discharge lamp 3, and the low voltage terminal of the secondary winding 5c of the electromagnetic transformer 5 is grounded.

  The current direction setting circuit 11 is provided connected to each primary winding 5 b of each electromagnetic transformer 5. The current direction setting circuit 11 is a circuit that sets the direction of the current flowing through each primary winding 5 b of each electromagnetic transformer 5 by sequentially reversing each electromagnetic transformer 5. The current direction setting circuit 11 connects the first terminal S1 of the primary winding 5b of the electromagnetic transformer 5 and the second terminal S2 of the primary winding 5b of the electromagnetic transformer 5 adjacent thereto to the power supply terminal D1 of the high-frequency power source 12. To do. Further, the current direction setting circuit 11 connects the second terminal S2 of the primary winding 5b of the electromagnetic transformer 5 and the first terminal S1 of the primary winding 5b of the electromagnetic transformer 5 adjacent thereto to the power supply terminal D2 of the high frequency power supply 12. Connect to. As a result, a current in the reverse direction flows through the primary winding 5b of each of the two adjacent electromagnetic transformers 5.

  In the discharge lamp lighting device 1 having such a configuration, when a current is supplied from the high-frequency power source 12 to the primary winding 5b of each electromagnetic transformer 5, the primary winding 5b of each adjacent electromagnetic transformer 5 is Current flows in the opposite direction. Accordingly, a current flows in the reverse direction in each secondary winding 5c of the adjacent electromagnetic transformer 5 as well. As a result, the voltage waveforms whose phases are mutually inverted are respectively applied to the two adjacent discharge lamps 3, and each discharge lamp 3 is lit.

  In the discharge lamp lighting device 1 in such a lighting state, as shown in FIG. 2, a magnetic field (see a dotted line in FIG. 2) is generated by each electromagnetic transformer 5. At this time, the winding directions of the primary windings 5b of the two adjacent electromagnetic transformers 5 are the same, and the directions of the currents flowing through the primary windings 5b of the two adjacent electromagnetic transformers 5 are opposite. Therefore, as shown in FIG. 4, the direction of the magnetic field generated by the primary winding 5b of the electromagnetic transformer 5 (arrow A in FIG. 4) is generated by the primary winding 5b of the electromagnetic transformer 5 adjacent thereto. This is opposite to the direction of the magnetic field (arrow B in FIG. 4). Thereby, since the mutual magnetic fields cancel each other, the magnetic field generated on the low pressure side is reduced.

  Similarly, the winding directions of the secondary windings 5c of the two adjacent electromagnetic transformers 5 are the same, and the direction of the current flowing through the secondary windings 5b of the two adjacent electromagnetic transformers 5 is the same. 4, the direction of the magnetic field generated by the secondary winding 5c of the electromagnetic transformer 5 (arrow A in FIG. 4) is also the secondary winding 5c of the adjacent electromagnetic transformer 5 as shown in FIG. Is opposite to the direction of the magnetic field generated by (arrow B in FIG. 4). As a result, the mutual magnetic fields cancel each other, so that the magnetic field generated on the high voltage side is also reduced.

  As described above, according to the first embodiment, the current direction setting circuit that sequentially sets the direction of the current flowing through the primary winding 5 b of each of the plurality of electromagnetic transformers 5 for each electromagnetic transformer 5. By providing 11, the direction of the magnetic field by the adjacent electromagnetic transformers 5 is reversed and the magnetic fields of each other cancel each other, so that the magnetic field generated from each electromagnetic transformer 5 can be suppressed as a whole. As a result, the influence of the magnetic field on the devices provided around the discharge lamp lighting device 1 can be suppressed. For example, beat noise (striped pattern) is generated on the display panel provided in the discharge lamp lighting device 1. Can be prevented.

  In particular, by sequentially reversing the direction of the current flowing through the primary winding 5b of each of the plurality of electromagnetic transformers 5 for each electromagnetic transformer 5, the adjacent electromagnetic transformers 5 cancel each other's magnetic field. The generated magnetic field can be efficiently and reliably suppressed as a whole. Furthermore, since it becomes possible to use the electromagnetic transformer 5 with the same winding direction for all the electromagnetic transformers 5, it is possible to simplify the manufacturing process.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS.

  The second embodiment of the present invention is basically the same as the first embodiment. In the second embodiment, differences from the first embodiment will be described. In addition, the same part as the part demonstrated in 1st Embodiment is shown with the same code | symbol, and the description is abbreviate | omitted.

  As shown in FIG. 5, the current direction setting circuit 11 divides the plurality of electromagnetic transformers 5 into a plurality of transformer groups T, and determines the direction of the current flowing through each primary winding 5 b of each electromagnetic transformer 5 as the transformer group T. Invert and set each time. In the second embodiment, the current direction setting circuit 11 divides the plurality of electromagnetic transformers 5 into a plurality of transformer groups T with the two electromagnetic transformers 5 as one transformer group T. Thereby, the two electromagnetic transformers 5 are handled as one transformer group T.

  The current direction setting circuit 11 includes a first terminal S1 of the primary winding 5b of each electromagnetic transformer 5 of the transformer group T and a second terminal S2 of the primary winding 5b of each electromagnetic transformer 5 of the transformer group T adjacent thereto. Is connected to the power supply terminal D 1 of the high-frequency power supply 12. Further, the current direction setting circuit 11 includes a second terminal S2 of the primary winding 5b of each electromagnetic transformer 5 of the transformer group T and a first terminal of the primary winding 5b of each electromagnetic transformer 5 of the transformer group T adjacent thereto. S1 is connected to the power supply terminal D2 of the high frequency power supply 12. As a result, a current in the reverse direction flows through the primary winding 5b of each electromagnetic transformer 5 of two adjacent transformer groups T.

  In the discharge lamp lighting device 1 having such a configuration, when a current is supplied from the high-frequency power source 12 to the primary winding 5b of each electromagnetic transformer 5, the primary winding 5b of each electromagnetic transformer 5 of the adjacent transformer group T. Current flows in the opposite direction. Accordingly, a current flows in the reverse direction also in the secondary winding 5c of each electromagnetic transformer 5 of the adjacent transformer group T. As a result, the voltage waveforms whose phases are mutually inverted are respectively applied to the two adjacent discharge lamps 3, and each discharge lamp 3 is lit.

  In the discharge lamp lighting device 1 in such a lighting state, as shown in FIG. 2, a magnetic field (see a dotted line in FIG. 2) is generated by each electromagnetic transformer 5. At this time, the winding directions of the primary windings 5b of the electromagnetic transformers 5 of the two adjacent transformer groups T are the same, and the primary windings 5b of the electromagnetic transformers 5 of the two adjacent transformer groups T Since the direction of the flowing current is reversed, as shown in FIG. 6, the direction of the magnetic field (arrow A in FIG. 6) generated by the primary winding 5b of each electromagnetic transformer 5 of the transformer group T is adjacent to it. The direction of the magnetic field generated by the primary winding 5b of each electromagnetic transformer 5 in the transformer group T is reversed (arrow B in FIG. 6). Thereby, since the mutual magnetic fields cancel each other, the magnetic field generated on the low pressure side is reduced.

  Similarly, the winding directions of the secondary windings 5c of the electromagnetic transformers 5 of the two adjacent transformer groups T are the same, and the primary windings of the electromagnetic transformers 5 of the two adjacent transformer groups T are the same. Since the direction of the current flowing in 5b is reversed, as shown in FIG. 6, the direction of the magnetic field generated by the secondary winding 5c of each electromagnetic transformer 5 of the transformer group T (arrow A in FIG. 6) The direction of the magnetic field generated by the secondary winding 5c of each electromagnetic transformer 5 of the adjacent transformer group T is reversed (arrow B in FIG. 6). As a result, the mutual magnetic fields cancel each other, so that the magnetic field generated on the high voltage side is also reduced.

  As described above, according to the second embodiment, the direction of the current flowing through the primary winding 5b of each of the plurality of electromagnetic transformers 5 is sequentially changed for each transformer group T, that is, for each of the two electromagnetic transformers 5. By providing the current direction setting circuit 11 that is inverted and set, the direction of the magnetic field by the adjacent transformer group T is reversed and the mutual magnetic fields cancel each other. Can be suppressed as. As a result, the influence of the magnetic field on the devices provided around the discharge lamp lighting device 1 can be suppressed. For example, beat noise (striped pattern) is generated in the display panel or the like provided in the discharge lamp lighting device 1. Can be prevented.

  In addition, by sequentially reversing the direction of the current flowing through the primary winding 5b of each electromagnetic transformer 5 for every two electromagnetic transformers 5, it is possible to use the electromagnetic transformers 5 having the same winding direction for all the electromagnetic transformers 5. Therefore, the manufacturing process can be simplified.

(Other embodiments)
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, in the above-described embodiment, a straight tube is used as the discharge lamp 3. However, the present invention is not limited to this. For example, a U-shaped or L-shaped bent tube may be used.

  In the above-described embodiment, the two electromagnetic transformers 5 are divided into one transformer group T, and the plurality of electromagnetic transformers 5 are divided into a plurality of transformer groups T. However, the present invention is not limited to this. One electromagnetic transformer 5 may be divided into one transformer group T, and a plurality of electromagnetic transformers 5 may be divided into a plurality of transformer groups T.

It is a top view which shows schematic structure of the discharge lamp lighting device which concerns on the 1st Embodiment of this invention. It is the sectional view on the AA line of the discharge lamp lighting device shown in FIG. It is a top view which shows the electrical connection of each part with which the discharge lamp lighting device shown in FIG. 1 is provided. It is the BB sectional drawing of the discharge lamp lighting device shown in FIG. It is a top view which shows the electrical connection of each part with which the discharge lamp lighting device which concerns on the 2nd Embodiment of this invention is provided. It is sectional drawing which shows schematic structure of the discharge lamp lighting device shown in FIG. It is a top view which shows the electrical connection of each part with which the discharge lamp lighting device which concerns on a prior art is equipped.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Discharge lamp lighting device 3 Discharge lamp 5 Electromagnetic transformer 5b Primary winding 5c Secondary winding 11 Current direction setting circuit T Transformer group

Claims (3)

A plurality of electromagnetic transformers respectively provided corresponding to a plurality of discharge lamps, each having a secondary winding connected to the discharge lamp and a primary winding in the same winding direction as the secondary winding;
Connected to the primary winding of each of the plurality of electromagnetic transformers and set by sequentially reversing the direction of the current flowing through the primary winding of each of the plurality of electromagnetic transformers for each of the electromagnetic transformers. A current direction setting circuit;
A discharge lamp lighting device comprising: A plurality of electromagnetic transformers respectively provided corresponding to a plurality of discharge lamps, each having a secondary winding connected to the discharge lamp and a primary winding in the same winding direction as the secondary winding;
A current that is provided connected to the primary winding of each of the plurality of electromagnetic transformers, divides the plurality of electromagnetic transformers into a plurality of transformer groups, and flows through the primary winding of each of the plurality of electromagnetic transformers. Current direction setting circuit that sequentially inverts and sets the direction of each transformer group;
A discharge lamp lighting device comprising: The discharge lamp lighting device according to claim 1, comprising the plurality of discharge lamps.

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