KR20060083897A - Lighting device - Google Patents

Abstract

SUMMARY OF THE INVENTION An object of the present invention is a lighting device including a plurality of curved dielectric barrier discharge lamps (EEFLs) and lighting them at the same time, which reduces the temperature difference between the electrode of the lamp curved portion and the electrode of the tube end, thereby preventing the bias of mercury in the lamp tube. This is to reduce luminance unevenness on the light emitting surface.

In a lighting apparatus in which a plurality of curved EEFLs 1 having curved portions 1A are provided in parallel, external electrodes 3 and 5 are formed at both ends and curved portions of each of the curved EEFLs, respectively, on the external electrodes 3 at both ends. The reverse phase rectangular wave voltage or sinusoidal wave voltage was applied to connect the external electrode 5 of the curved portion to GND.

Curved section, lamp tube, EEFL, frame, rubber holder, transformer, inverter

Description

Lighting device {LIGHTING DEVICE}

1 is a plan view of a backlight of a first embodiment of the present invention;

2 is a temperature distribution graph of the backlight of the above embodiment.

3 is a luminance distribution graph of a backlight of the embodiment;

4 is a plan view of a backlight of a second embodiment of the present invention;

Fig. 5 is a bottom view of the backlight of the above embodiment.

Fig. 6 is a plan view of a backlight of a third embodiment of the present invention.

Fig. 7 is a plan view and a side view of a C-type curved EEFL used for the backlight of the fourth embodiment of the present invention.

Fig. 8 is a plan view and a side view of a U-shaped curved EEFL used for the backlight of the fourth embodiment of the present invention.

Fig. 9 is a plan view in which part of the backlight of the fourth embodiment is omitted.

Fig. 10 is a plan view of a backlight of the prior art;

11 is a temperature distribution graph of a backlight of a conventional example.

12 is a graph of luminance distribution of a backlight of a conventional example.

<Explanation of symbols for the main parts of the drawings>

1: EEFL

1A: bend

2: frame

3: electrode

4: rubber holder

5: electrode

6: trance

7: inverter

[Document 1] Japanese Unexamined Patent Publication No. 2002-82327

[Document 2] Japanese Patent Publication No. 2001-507824

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lighting apparatus including a large number of fluorescent lamps used for liquid crystal displays, liquid crystal televisions, instrument display panels, and the like.

Recently, as a backlight for a liquid crystal display, a liquid crystal TV, and an instrument display panel, a neon-argon containing mercury is contained inside a transparent glass tube which is coated with a phosphor on the inner wall and sealed at both ends for the purpose of lowering power consumption and reducing costs. Backlight using a large number of short pitch U tubes or C tubes of a dielectric barrier discharge lamp (referred to as "EEFL") in which a mixed gas such as a gas is sealed as a discharge medium and a thin film of metal or the like is coated on the outer walls of both ends of the glass tube to form an external electrode. Is becoming mainstream. Although the structure of the backlight using such a U tube EEFL or a C tube EEFL is shown in FIG. 10, an external electrode type EEFL in which the electrodes 3 are disposed only outside both ends of the glass tube bent in a short pitch U tube shape or C tube shape. (1) is provided in the backlight frame 2. In the backlight frame 2, a reflecting plate 2 'for reflecting the light emitted from the lamp is provided.

At present, in order to reduce the number of lamps, the use of the U tube or the C tube of the structure which bend | folded the straight tube-shaped glass tube in the center has become main. In addition, in a large-sized backlight, the tube length of the EEFL becomes long, and the tube voltage also needs to be turned on at 2000 V (one 1000 Vrms) or more. However, when the tube voltage is turned on at 2000 V or higher, ozone is generated and thus cannot be used. Further, in the design of a backlight using a large number of U tubes and C tubes, when the curved portion 1A of the lamp is provided outside the effective light emitting portion where the reflecting plate 2 'is provided, as shown in FIG. Since the tube wall temperature on the curved part 1A side becomes lower than the 3) side, mercury is shifted to this part, and the quantity of mercury gas of the whole lamp decreases, so-called pink discharge with low luminance becomes. In addition, as shown in Fig. 12, since the light emitting area is larger on the curved portion 1A side than on the electrode 3 side, the amount of lamp light increases, and luminance unevenness occurs on the plate surface of the backlight. Further, as the tube voltage of the lamp increases, current leakage also increases, and as a result, luminance unevenness occurs as the luminance in the tube axis direction of the lamp gradually decreases from the electrode side toward the curved side.

[Patent Document 1] Japanese Unexamined Patent Publication No. 2002-82327

[Patent Document 2] Japanese Patent Publication No. 2001-507824

SUMMARY OF THE INVENTION The present invention has been made in view of such a conventional technical problem, and includes a plurality of curved dielectric barrier discharge lamps (EEFLs) such as C tubes or U tubes, and simultaneously illuminates the lighting apparatus. It is an object of the present invention to provide a lighting apparatus which can prevent the blurring of mercury in the lamp tube by reducing the temperature difference between the electrode and the electrode at the tube end, and can reduce the luminance unevenness on the light emitting surface by lowering the luminance of the lamp curved portion. .

In the illuminating device of the present invention, a phosphor film is formed on an inner wall of the glass tube, one or more rare gases, or mercury and one or more rare gases are enclosed in the internal discharge space of the glass tube, so that both ends of the glass tube are closed, and An illuminating device comprising a plurality of curved fluorescent lamps having curved portions formed in an intermediate portion, wherein an external electrode is formed at both ends and a curved portion of the curved fluorescent lamp, and inverse phases are formed at the external electrodes at both ends, respectively. An external electrode of the curved portion is connected to GND by applying a square wave voltage or a sine wave voltage.

In the illumination device of the present invention, a phosphor film is formed on an inner wall of the glass tube, one or more rare gases, or mercury and one or more rare gases are enclosed in the interior discharge space of the glass tube so that both ends of the glass tube are closed. In a lighting apparatus in which a plurality of curved fluorescent lamps having curved portions are formed in the middle portion of a glass tube, an external electrode is formed at both ends and the curved portions of the curved fluorescent lamp, and each phase is in phase with the external electrodes at both ends. The external electrode of the curved portion is connected to GND by applying a rectangular wave voltage or a sine wave voltage of -phase).

Moreover, in the illuminating device of this invention, in the said illuminating device, the said curved fluorescent lamp is a C tube shape or U tube shape, It is characterized by the above-mentioned.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described based on drawing.

(1st embodiment)

Fig. 1 shows a curved multi-angle backlight as a first embodiment of the lighting apparatus of the present invention. In the backlight of the present embodiment, a plurality of C tube EEFLs 1 are provided in the frame 2. The frame 2 is comprised by the container-shaped reflection case 2 'which comprises a reflective film, and the diffuser plate provided so that the upper surface may not be shown, but the several C-pipe EEFL 1 is provided in the inside, have. Both ends of each EEFL 1 have external electrodes 3 embedded in the exterior of the reflective case or inserted into the conductive rubber holder 4. Moreover, the external electrode 5 is provided in the curved part 1A of each EEFL 1, and is connected to GND, respectively. The curved portion 1A of each EEFL 1 is disposed in the effective light emitting region, that is, the reflective film case 2 'provided in the frame 2. Moreover, the power supply circuit is comprised so that the inverted rectangular wave voltage or the sine wave voltage may be applied to the rubber holder 4 of the both ends of each EEFL 1 through the transformers 6 and 6 from the inverter 7. In the figure, an applied voltage waveform is shown in the circle 10.

The luminance distribution at the time of lighting of the backlight of the said structure is shown in FIG. 2, and the temperature distribution is shown in FIG. As described above, the external electrode 5 is provided at the curved portion 1A of each C tube EEFL 1, grounded to a GND potential, and reversed on the electrodes 3 at both ends of each EEFL 1. The tube voltage can be reduced by applying a rectangular wave voltage or a sinusoidal wave voltage. That is, even when a voltage of 2000 Vrms is applied between a pair of external electrodes 3 provided at both ends of the C tube EEFL 1, the potential with respect to the GND potential of each external electrode 3 is 1000, which is half of the tube voltage. Can be reduced to Vrms. As a result, the luminance unevenness in the tube axis direction as described above can be prevented and a substantially uniform luminance distribution can be obtained.

Although the curved portion 1A is not shown, the curved portion 1A in each EEFL 1 as shown in the graph of FIG. 2 by being provided in the reflection case provided on the inner surface of the frame 2, that is, in the effective light emitting region. The difference in temperature between the c) side and the electrode 3 side is reduced to prevent blurring of mercury, and as a result, occurrence of pink discharge can be suppressed. In addition, since the electrode 5 is formed in the curved portion 1A of each C tube EEFL 1, the light of the curved portion 1A can be blocked, and as shown in FIG. 3, the curved portion 1A of each EEFL 1 is shown. The luminance unevenness on the backlight plate surface can be reduced by lowering the luminance of.

In addition, although the C pipe EEFL was employ | adopted in the said embodiment, the U pipe EEFL can also be employ | adopted instead, Furthermore, the tube cross section of a lamp tube is not only circular but also an oval flat tube by the curved tube of those C and U tubes. It is also possible to employ. In addition, in this embodiment, since the C tube EEFL was employ | adopted, the curved part was called "bent part", but in U tube EEFL, it is assumed that it is similarly called the common name "bent part" for the connection part called "short side part." These also apply to the other embodiments described below.

(2nd embodiment)

4 and 5 show the backlight of the second embodiment of the present invention. In the present embodiment, the tube end portions for mounting each of the plurality of C tube EEFLs 1 with the rubber holder 4 containing the curved portion 1A and the external electrode 3 are arranged in different positions, and the frame 2 On the rear side of the back side), two inverters 7 are arranged on both sides, and a transformer 6 for applying an antiphase rectangular wave voltage or a sinusoidal wave voltage to the external electrodes 3 at each end is connected to each external electrode ( It is characterized by a structure installed at a position close to 3). 4 and 5, the same reference numerals are given to elements common to the first embodiment shown in FIG. As a result, in the second embodiment, since the plurality of C tube EEFLs 1 are arranged in opposite directions to each other, the positions of the external electrode 3 portions in which the temperature and the luminance increase with respect to the curved portion 1A are changed from each other. The axial temperature difference and the plate brightness difference can be reduced.

(Third embodiment)

Next, the backlight of the third embodiment of the present invention will be described with reference to FIG. The characteristic of 3rd Embodiment is that the rectangular wave voltage or sine wave voltage applied to the both ends side rubber holder 4 of each C-pipe EEFL 1 in phase with respect to 1st Embodiment shown in FIG. have.

That is, in the backlight of the present embodiment, a plurality of C tube EEFLs 1 are arranged in the frame 2, and the external electrodes 3 at each of both ends of each EEFL 1 are embedded with electrodes or conductive rubber holders ( 4), an external electrode 5 is provided at the curved portion 1A of each EEFL 1, and connected to GND. The curved portion 1A of each EEFL 1 is located in the effective light emitting area. The power supply circuit is configured to apply a rectangular wave voltage or a sinusoidal wave voltage in phase to the rubber holders 4 at both ends of each EEFL 1 from the inverter 7 through a common transformer 6. In the figure, the cycle of applied voltage is shown in cycle 11.

In the backlight having the above configuration, since an alternating voltage in phase is applied to the external electrodes 3 at both ends of the lamp, no potential difference occurs between the two electrodes. For this reason, the current leakage between electrodes which arises when the alternating voltage of a different phase is applied to both electrodes does not generate | occur | produce. Therefore, the luminance distribution and the temperature distribution at the time of lighting are almost the same as in the first embodiment, and as a result, the occurrence of pink discharge can be suppressed and the luminance nonuniformity on the backlight plate surface can be reduced. In addition, in the case of the first embodiment shown in Fig. 1, at least two transformers 6 are required to apply the reverse phase voltage, whereas in the case of this second embodiment, at least one transformer 6 is required. There is an advantage that can be used in common.

In addition, although the C tube EEFL was employ | adopted in the said embodiment, U tube EEFL can also be employ | adopted instead, Furthermore, the tube cross section of a lamp tube is not only circular but also an oval flat tube by the curved tube of those C and U tubes. It is also possible to employ.

(4th embodiment)

The backlight of the fourth embodiment of the present invention will be described with reference to Figs. The feature of the present embodiment lies in the intermittent lighting function of the curved EEFLs 1 of various lamps. As shown in Fig. 7, the EEFL 1 is coated with a phosphor on the inner wall of the glass tube, and after the inside of the glass tube is put under a negative pressure, a small amount of Ar gas, Ne gas and mercury are sealed to seal both ends of the glass tube. Moreover, it is the structure which formed the solder layer about 20 mm in length which consists of metals, such as Sn and Ag, as the electrode 3 in the both ends of the said glass tube. The film thickness of the electrode 3 is set to a thickness of 0.5 µm to 2 µm, and the shape of the lamp itself is C type. The outer diameter dimension of a glass tube can respond to φ2.4mm to φ4mm. Moreover, the curved EEFL 1 used in this embodiment forms the external electrode 5 in the outer wall of the curved part 1A like the electrode material of the external electrode 3 of both ends. The external electrode 5 of this curved portion 1A has an electrode length twice that of the external electrode 3 at both ends of the tube. Since the current flowing in the curved portion 1A is twice as large as the current flowing in both ends of the tube, it is necessary to improve its durability, and the electrode length is doubled to increase the surface area.

In the driving method of the EEFL 1 employed in the present embodiment, an in-phase sine wave voltage of 40 kV to several hundred kV is applied to the external electrodes 3 at both ends of the lamp, and the tube 5 is applied to the electrode 5 of the curved portion 1A. The sinusoidal voltage in reverse phase is applied at the same frequency applied to both ends. It is because this method can realize an EEFL which is electrically safe and has a tube length of 800 mm or more and a diameter of φ4 mm or less, which has been impossible until now, without corona discharge or ozone generation. Instead of the C-type curved EEFL 1, the U-type curved EEFL 1 shown in Fig. 8 can be adopted. In this case, the size, electrode length, thickness, and the like are equivalent to those in FIG.

Next, a configuration of a backlight for lighting the curved EEFL 1 in multiple and intermittently will be described with reference to FIG. In the backlight of this embodiment, a square wave or a sine wave voltage is applied to the electrodes 3 of each of the curved EEFLs 1 and the electrodes 5 of the curved portions 1A by a transformer 6 so as to discharge the light.

For convenience of explanation, in order to distinguish the multiple EEFLs 1, the symbols are in turn 1-1, 1-2,... In order to distinguish the straight pipe portions of the respective EEFLs 1, straight pipe portions on both sides of the EEFL 1-1 are denoted by 1-11 and 1-12, respectively. In addition, the transformers 6-11, 6-12, 6-13,... It is distinguished by. In addition, the transformers applying voltages to the electrodes of the curved portions 1A of the respective EEPLs 1 also have 6-21, 6-22, 6-23,... Distinguish by.

The driving method in the backlight of the above embodiment will be described. The external electrodes 5 formed on the curved portions 1A of the respective EEFLs 1 are applied with the same voltage and the same frequency (tens of tens to hundreds of kHz) in the reverse phase with the external electrodes 3 and 3 at both ends of the tube. The voltage applied to the electrodes 3 at both ends of the tube is an electrically safe design and the waveform is in phase. Thus, the output electrical signal is varied by an IC or the like arranged in the circuit, and voltage is sequentially applied to both end electrodes 3. Thereby, the intermittent drive which makes light of the straight pipe parts 1-11, 1-12, 1-21, 1-22, ... of each EEFL 1 in order becomes possible.

In addition, in order to change the brightness of the backlight itself, it is also necessary to intermittently drive all the EEFLs 1 which are not intermittent driving of the straight pipe portion, but as the driving method in that case, the external electrode of the curved portion 1A ( Similarly to 5) above, a voltage equal to the voltage applied to the external electrodes 3 at both ends of the tube and a voltage applied to the external electrodes 3 at both ends of the tube can be intermittently driven.

In addition, although the backlight was illustrated as an embodiment of the present invention above, the present invention can be widely applied to lighting devices having the same configuration and different uses.

According to the lighting apparatus of the present invention, in simultaneously lighting a large number of curved EEFLs such as a C tube or a U tube, the temperature difference between the external electrode of the lamp curved portion and the external electrode of the tube end is reduced so that the mercury in the lamp tube is biased. Can be prevented, and the brightness of the lamp bent portion can be lowered to make the brightness on the light emitting surface uniform.

Claims (7)

A phosphor coating is formed on the inner wall of the glass tube, one or more rare gases, or mercury and one or more rare gases are enclosed in the internal discharge space of the glass tube so that both ends of the glass tube are blocked, and a curved portion is formed in the middle of the glass tube. In the illuminating apparatus which provided a plurality of curved fluorescent lamps which there is, Forming external electrodes at both ends and the curved portions of the curved fluorescent lamp; And an external rectangular wave voltage or a sine wave voltage applied to the external electrodes of the both ends, respectively, to connect the external electrodes of the curved portions to GND. The illuminating device according to claim 1, wherein the plurality of curved fluorescent lamps are arranged in a reflection case forming a frame, and the curved portion is disposed in an effective light emitting region in the reflection case. The plurality of curved fluorescent lamps of claim 2, wherein the plurality of curved fluorescent lamps are disposed so that the positions of the external electrodes of the both ends and the curved external electrodes are opposite to each other, and the rectangular wave voltage or the sine wave voltage is applied to the plurality of curved fluorescent lamps. The inverter circuit for application is distributedly arrange | positioned at the both sides of the back side of the said frame. The illuminating device according to claim 3, wherein the curved fluorescent lamp has a C tube shape or a U tube shape. A phosphor coating is formed on the inner wall of the glass tube, one or more rare gases, or mercury and one or more rare gases are enclosed in the internal discharge space of the glass tube so that both ends of the glass tube are blocked, and a curved portion is formed in the middle of the glass tube. In the illuminating apparatus which provided a plurality of curved fluorescent lamps which there is, Forming external electrodes at both ends and the curved portions of the curved fluorescent lamp; And a rectangular wave voltage or a sine wave voltage in phase, respectively, to the external electrodes of the both ends, thereby connecting the external electrodes of the curved portion to GND. The illuminating device according to claim 5, wherein the plurality of curved fluorescent lamps are arranged in a frame in which a reflecting plate is formed, and the curved portion is disposed in an effective light emitting region which is an area in which the reflecting plate is provided. The illuminating device according to claim 6, wherein the curved fluorescent lamp has a C tube shape or a U tube shape.

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