JP2007053026A - Lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device using a dielectric barrier discharge lamp capable of stably lighting at a low cost. <P>SOLUTION: The lighting device comprises a plurality of glass tubes 2 with different shapes each having a bending portion formed in C-shape or U-shape, a phosphor coated on an inner wall of each glass tube 2, a discharge medium filled inside each glass tube 2 of which both ends are sealed, an external electrode 3 formed on outer walls at both ends of each glass tube 2, and an external electrode 4 formed at an outer wall of the bending portion of each glass tube 2. A high voltage of antiphase or a grounding voltage is impressed on this bending portion and each of both end parts. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an illumination device using a dielectric barrier discharge lamp.

  CCFL (Internal Electrode Cold Cathode Discharge Lamp) has been the mainstream for conventional LCD monitors or LCD TV direct-type backlights, and in recent years, the cost of backlight units has become increasingly important. It is coming. The EEFL (outer electrode type dielectric barrier discharge lamp) can drive a plurality of EEFLs with a single inverter transformer because of its characteristics, and thus can be manufactured at a lower cost than the conventional CCFL. In recent years, LCD modules have been actively developed to support moving images such as TV. As a problem in dealing with moving images, there are moving image blurs in the case of LCDs, and various companies have taken measures to try to improve the response speed of LCDs and intermittently drive the backlight unit.

  One of the intermittent driving methods is field sequential (hereinafter referred to as “FS”) driving. If the FS drive is used, there is a cost merit that a CF (color filter) becomes unnecessary. As a lamp performance necessary for the FS drive, there is a problem of shortening the afterglow time of the phosphor generated when the lamp is driven intermittently. The prospect of substantially resolved practically standing for this problem.

FIG. 7 is a top view of a conventional backlight unit. In FIG. 7, 31 represents a CCFL lamp. In the conventional direct type backlight unit, a plurality of CCFL lamps 31 are arranged, and one inverter transformer 32 is connected to each lamp 31, and the output signal of the inverter 31 is changed by changing the output signal of the inverter 32. A system in which the first to nth lamps are sequentially intermittently driven has been adopted. However, such a conventional backlight unit has the problem that the number of inverter transformers is the same as the number of discharge lamps, which increases the cost.
Special table 2001-507824 gazette

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide an illumination device capable of stable lighting at low cost.

  The lighting device according to the first aspect of the present invention includes a plurality of irregularly shaped glass tubes whose bent portions are formed in a C shape or a U shape, a phosphor applied to the inner wall of each glass tube, and the interior of each glass tube. A plurality of dielectric barrier discharges comprising: an enclosed discharge medium; external electrodes formed on outer walls at both ends of each glass tube; and a bent portion external electrode formed on an outer wall of a bent portion of each glass tube A power supply that applies a high voltage in phase to each of the bent portions of the lamp and the dielectric barrier discharge lamp, and applies a high voltage or ground voltage in opposite phases to the bent portions to each of both ends of the dielectric barrier discharge lamp. And a circuit.

  According to a second aspect of the present invention, in the lighting device according to the first aspect, the power supply circuit is an inverter, and the inverter is installed at a central portion on the back side of the casing of the lighting device.

  According to the present invention, a high voltage having the same phase is applied to each bent portion of each dielectric barrier discharge lamp, and a high voltage or ground voltage having a phase opposite to that of the bent portion is applied to each end of each dielectric barrier discharge lamp. Thus, the lighting circuit pattern can be simplified, and the number of power supply circuit components such as a transformer and an oscillation circuit can be reduced.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  (First Embodiment) FIG. 1 is a diagram showing a configuration of an EEFL lamp (outer electrode type dielectric barrier discharge lamp) according to a first embodiment of the present invention. FIG. 1 shows an EEFL lamp 1 having a C-shaped bent portion. In FIG. 1, 1 is an EEFL lamp, 2 is a C-type glass tube, 3 is an electrode portion at both ends of the glass tube, and 4 is an electrode portion at a bent portion.

  In the C-type EEFL lamp 1 of the present embodiment, a phosphor is applied to the inner wall of the glass tube 2, and after the inside of the glass tube 2 is in a negative pressure state, a small amount of Ar gas, Ne gas and mercury are enclosed. It is. At both ends of the outer wall surface of the C-type glass tube 2, a lead-free metal solder layer mainly composed of Sn, Zn or the like is formed as the electrode portion 3 having a length of about 20 mm. A similar solder layer is formed on the bent portion of the glass tube 2 as the electrode portion 4 having a length of about 40 mm. The film pressure of the electrode parts 3 and 4 is set to a thickness of 0.5 μm to 2 μm. The outer diameter of the glass tube 2 can correspond from φ2.4 to φ4.

  The electrode part 4 formed in the bent part of the glass tube 2 has twice the electrode length of the electrode part 3 at both ends of the tube. This is because the current flowing in the bent portion is theoretically doubled at both ends of the tube, so that it is preferable to double the electrode length and increase the surface area in order to improve the durability performance by the current. The lamp driving method applies the same phase sine wave voltage from 40 kHz to several hundred Khz to the electrode portions 3 at both ends of the lamp, and applies the same frequency to the electrode portions 3 at both ends of the tube to the electrode portion 4 at the bent portion. Apply an antiphase sine wave.

  According to the present embodiment, it is possible to supply EEFL which is electrically safe and has a tube length of 800 mm or more, which has been impossible until now, an outer diameter of φ4 or less, and is free from corona discharge and ozone. It becomes.

  Further, according to the EEFL lamp of the present embodiment, it is possible to deal with a place where two lamps are originally required with one lamp, so one unit for each electrode unit 3 and one unit for each electrode unit 4. It is possible to light up by connecting a total of three transformers, and the overall cost of the lighting device can be reduced.

  (Second Embodiment) FIG. 2 shows a U-shaped EEFL lamp 1 as an EEFL lamp according to a second embodiment of the present invention. The EEFL lamp 1 of this embodiment is U-shaped, and is provided with electrodes 3 at both ends and electrode portions 4 at bent portions. These electrode portions 3 and 4 are the same as those in the first embodiment.

  Even in the EEFL lamp of the second embodiment, the same effect as that of the EEFL lamp of the first embodiment can be obtained.

(Third Embodiment) FIG. 3 is an explanatory diagram of the configuration of an EEFL lamp according to a third embodiment of the present invention. In FIG. 3, 5 represents a red phosphor, 6 represents a green phosphor, and 7 represents a blue phosphor. These are phosphors having short afterglow characteristics, for example, Y ₂ O ₂ : Eu for red, LaPO ₄ : Ce, Tb for green, and (SrCaBaMb) ₅ (PO ₄ ) ₃ Cl for blue. Eu is used. In FIG. 3, the same elements as those in FIGS. 1 and 2 are denoted by the same reference numerals.

  The EEFL lamp of the present embodiment uses a U-type or C-type lamp having the basic structure of the first or second embodiment as a set of three bodies as shown in the drawing for the lighting device. A fluorescent substance interval of 2 to 3 mm is provided in the bent part of each lamp 1, and the three primary colors of short afterglow fluorescent substance are applied to the part including the straight tube part. The reason why the fluorescent material application interval of the bent portion is set at 2 to 3 mm is to prevent the phosphor color facing each other from being emitted when each phosphor emits light.

  The three primary colors are configured such that the red phosphor 5-Green phosphor 6 is a pair, the blue phosphor 7-Red phosphor 5 is a pair, and the green phosphor 6-Blue phosphor 7 is a pair. . If these three bodies are combined into one set and incorporated in the backlight unit as a light source, intermittent driving with R, G, and B color schemes becomes possible. In addition, said color scheme is an example and a combination can be set freely.

  (Fourth Embodiment) FIG. 4 is a diagram showing a configuration of a backlight unit as an illumination apparatus according to a fourth embodiment of the present invention. In FIG. 4, 11 and 12 are electrode portions at both ends of the tube, 13 is an electrode portion at a bent portion, and 14 is a rubber holder. 15 and 16 are transformers, and 17 is also a transformer.

  In the backlight unit of the present embodiment, a set of three EEFL lamps 1 of the third embodiment is used. If the electrode portion 13 is formed in the bent portion of the lamp 1, the bent portion is held by the rubber holder 14 made of silicon or the like for the purpose of holding the lamp 1 when installed in the backlight unit. The portion can be shielded from light by the rubber holder 14, and a structure having no problem in optical characteristics can be obtained.

  A driving method in the backlight unit of the present embodiment will be described. The same voltage and the same frequency (several tens of kHz to several hundreds of kHz) are applied to the electrode part 13 formed in the bent part of the EEFL lamp 1 in the opposite phase. The voltage applied to both ends of the tube has the same phase as an electrically safe design. Therefore, an output electric signal is changed by an IC or the like arranged in the circuit, and a voltage is sequentially applied to the tube end electrode portions 11 and 12. Then, intermittent driving can be performed in which the straight tube portion of the modified EEFL lamp 1 such as L-type or C-type emits light sequentially.

  As the backlight unit, if two or three lamp sets of the third embodiment are incorporated, a backlight unit compatible with FS drive can be obtained, and CF-less is possible.

  (Fifth Embodiment) FIG. 5 is a top view of a backlight unit (B / L) according to a fifth embodiment of the present invention, and FIG. 6 is a circuit diagram. The present embodiment is characterized in that a high voltage having the same phase is applied to the bent portion of each lamp 1, and a high voltage (or ground voltage GND) having a phase opposite to that of the central portion is applied to both ends. . Moreover, the inverter 20 is installed in the center part on the back side of B / L.

  According to the present embodiment, the bent portion of the C-type or U-type EEFL lamp 1 is electrically connected as the high voltage application side, and the voltage is applied in common by the transformer 22 having opposite phases at both ends. The pattern of the lighting circuit can be simplified, and the number of transformers and oscillation circuits for boosting can be reduced. Moreover, mercury can be diffused in the axial direction by using the heat of the inverter 20 and the electrodes to compensate for mercury vaporization at the center of the lighting device.

The figure which shows the structure of the EEFL lamp whose bending part of the 1st Embodiment of this invention is a C type | mold. The figure which shows the structure of the EEFL lamp whose bending part of the 2nd Embodiment of this invention is a U type. Explanatory drawing of the EEFL lamp of the 3rd Embodiment of this invention. The figure which shows the structure of the backlight unit of the 4th Embodiment of this invention. The top view which shows the structure of the backlight unit of the 5th Embodiment of this invention. The bottom view which shows the structure of the backlight unit of the 5th Embodiment of this invention. The top view which shows the structure of the conventional backlight unit.

Explanation of symbols

1 EEFL lamp 2 Glass tube 3 4 Electrode part

Claims (2)

A plurality of irregularly shaped glass tubes whose bent portions are formed in a C shape or a U shape, a phosphor applied to the inner wall of each glass tube, a discharge medium enclosed in each glass tube, and each glass A plurality of dielectric barrier discharge lamps comprising external electrodes formed on the outer walls at both ends of the tube, and bent portion external electrodes formed on the outer wall of the bent portion of each glass tube;
A power circuit that applies a high voltage in the same phase to each bent portion of each of the dielectric barrier discharge lamps, and applies a high voltage or ground voltage having a phase opposite to that of the bent portions to each of both ends of each of the dielectric barrier discharge lamps. A lighting device comprising: The lighting device according to claim 1, wherein the power supply circuit is an inverter, and the inverter is installed at a central portion on the back side of the casing of the lighting device.

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