CN1809238A - Luminaire - Google Patents

Abstract

In a lighting device with multiple bent tube dielectric barrier discharge lamps (EEFL) that can be lit at the same time, the temperature difference between the electrode at the bent part of the lamp and the electrode at the end of the lamp tube can be reduced, and mercury in the lamp tube can be prevented. Concentrate and reduce brightness unevenness on the light-emitting surface. In an illuminating device in which a plurality of bent tube EEFLs with curved parts (1A) are arranged side by side, external electrodes (3, 5) are formed on both ends of each bent tube EEFL lamp and on the bent part, respectively A rectangular wave voltage or a sine wave voltage is applied to the external electrodes (3) at both ends, and the external electrode (5) at the bent part is connected to GND.

Description

lighting device

technical field

The present invention relates to a lighting device with a plurality of fluorescent lamps used in liquid crystal displays, liquid crystal televisions, display screens for instruments and the like.

Background technique

Recently, as a backlight for liquid crystal displays, LCD TVs, instrument displays, etc., for the purpose of low power consumption and low cost, small-pitch U-shaped tubes using multiple dielectric barrier discharge lamps (called 'EEFL') Or the backlight source of the C-shaped tube is becoming the mainstream. The composition of the dielectric barrier discharge lamp is as follows: the phosphor is coated on the inner wall, and the mixed gas such as neon and argon containing mercury is used as a discharge medium, and the two ends are sealed. In the transparent glass tube, the outer wall at both ends of the glass tube is covered with a thin layer such as metal to form an external electrode. The structure of the backlight adopting the EEFL of this U-shaped tube or the EEFL of the C-shaped tube is shown in Fig. The configuration of the external electrode type EEFL1 is that electrodes 3 are arranged on both ends of the glass tube. Also, in the backlight frame 2, a reflector 2' for reflecting light is provided.

At present, in order to reduce the number of lamps, a U-shaped tube or a C-shaped tube structure in which a straight glass tube is bent in the middle is mainly used. In addition, in a large backlight, the tube length of the EEFL becomes longer, and in order to light the lamp, the lamp voltage must be more than 2000V (1000Vrms on one side). However, when the lamp is lit with a lamp voltage above 2000V, ozone is generated, so it cannot be used. In addition, in the design of the backlight using multiple U-shaped tubes and C-shaped tubes, when the curved part 1A of the lamp is arranged outside the effective light-emitting part with the reflector 2', as shown in Figure 11 , because the temperature of the tube wall on the bent portion 1A side is lower than that on the electrode 3 side, mercury is concentrated in this portion, and as a result, the amount of mercury vapor in the entire lamp is reduced, resulting in a so-called pink discharge with reduced brightness. In addition, as shown in FIG. 12, since the light emitting area on the side of the curved portion 1A is larger than that on the side of the electrode 3, the luminous flux of the lamp increases, and brightness unevenness occurs on the board surface of the backlight. Furthermore, as the tube voltage of the lamp increases, the current leakage also increases. As a result, the luminance in the tube axis direction of the lamp gradually decreases from the electrode side to the bent portion side, resulting in uneven luminance.

Patent Document 1: JP-A-2002-82327

Patent Document 2: Special Publication No. 2001-507824

Contents of the invention

The present application is made based on the above-mentioned technical problems, and its purpose is to provide a lighting device which has a bent tube type dielectric barrier discharge lamp (EEFL) like a plurality of C-shaped tubes or U-shaped tubes and makes them simultaneously Lighting, by reducing the temperature difference between the electrode at the curved part of the lamp and the electrode at the end of the tube, it can prevent the concentration of mercury in the lamp tube, reduce the brightness of the curved part of the lamp, and reduce the uneven brightness on the light emitting surface.

The lighting device of the present application is a lighting device in which a plurality of curved tube fluorescent lamps are arranged side by side. or more than one rare gas, or mercury and one or more rare gases, seal both ends of the glass tube, and form a curved part in the middle of the glass tube, in the lighting device, It is characterized in that external electrodes are formed at the two ends and the curved part of the curved tube fluorescent lamp, and the opposite-phase rectangular wave voltage or sine wave voltage is respectively applied to the external electrodes at the two ends, while the curved part Connect the external electrodes to GND.

In addition, the lighting device of the present application is a lighting device in which a plurality of curved tube fluorescent lamps are arranged side by side. One or more rare gases, or mercury and one or more rare gases, seal the two ends of the glass tube, and form a curved part in the middle of the glass tube, in the lighting device Among them, it is characterized in that external electrodes are formed at the two ends and the curved part of the curved tube fluorescent lamp, and the same-phase rectangular wave voltage or sine wave voltage is respectively applied to the external electrodes at the two ends, and the curved part Connect the external electrodes to GND.

Furthermore, in the lighting device of the present application, the curved tube fluorescent lamp of the above-mentioned lighting device is in the shape of a C-shaped tube or a U-shaped tube.

With the lighting device of the present application, when lighting multiple C-shaped or U-shaped bent tube EEFLs at the same time, since the temperature difference between the external electrodes of the bent portion of the lamp and the external electrodes of the tube ends is reduced, the lamp can be prevented from The concentration of mercury in the tube reduces the brightness of the curved part of the lamp, making the brightness of the light-emitting surface uniform, thereby uniformly emitting light.

Description of drawings

FIG. 1 is a top view of a backlight according to a first embodiment of the present invention.

FIG. 2 is a temperature distribution diagram of the backlight of the above embodiment.

FIG. 3 is a luminance distribution diagram of the backlight of the above embodiment.

FIG. 4 is a top view of a backlight according to a second embodiment of the present invention.

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

FIG. 6 is a top view of a backlight according to a third embodiment of the present invention.

7 is a plan view and a side view of a C-bend EEFL used in a backlight according to a fourth embodiment of the present invention.

8 is a plan view and a side view of a U-bend type EEFL used in a backlight according to a fourth embodiment of the present invention.

FIG. 9 is a partially omitted plan view of the backlight according to the fourth embodiment.

FIG. 10 is a plan view of an example of a conventional backlight.

FIG. 11 is a temperature distribution diagram of an example of a conventional backlight.

Fig. 12 is a diagram showing a luminance distribution of an example of a conventional backlight.

Label description

1EEFL, 1A bending part, 2 lamp frame, 3 pole, 4 rubber lamp holder, 5 pole, 6 transformer, 7 inverter

Detailed ways

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

first embodiment

FIG. 1 shows a backlight of an elbow type multi-lamp as a first embodiment of the lighting device of the present invention. In the backlight of this embodiment, multiple C-shaped tubes EEFL1 are arranged side by side in the lamp frame 2 . The lamp frame 2 is composed of a container-shaped reflector lamp box 2' constituting a reflector and a diffuser plate not shown in the figure that is arranged to cover it, and a plurality of C-shaped tubes EEFL1 are arranged side by side inside it. The two ends of each EEFL1 are inserted into the external electrode 3 or conductive rubber socket 4 outside the reflector lamp box. In addition, external electrodes 5 are provided on the bent portion 1A of each EEFL 1, and are connected to GND respectively. The curved portion 1A of each EEFL 1 is arranged in the effective light-emitting area, that is, in the reflector lamp box 2' provided in the lamp frame 2. In addition, a power supply circuit is formed, and this circuit applies an inverted rectangular wave voltage or a sine wave voltage to the rubber lamp sockets 4 at both ends of each EEFL1 from the inverter 7 through the transformers 6 and 6 . The circle 10 in the figure represents the applied voltage waveform.

FIG. 2 shows the temperature distribution when the backlight having the above configuration is turned on, and FIG. 3 shows the luminance distribution. As mentioned above, the external electrode 5 is provided at the bent portion 1A of each C-shaped tube EEFL1, and it is grounded to become the GND potential. By applying a rectangular wave voltage or a sine wave voltage with opposite phases to the electrodes 3 at both ends of each EEFL1, This reduces the lamp voltage. That is, when a 2000Vrms voltage is applied between a pair of external electrodes 3 provided at both ends of the C-shaped tube EEFL1, the potential relative to the GND potential of each external electrode 3 can also be reduced to 1000Vrms, which is half of the lamp voltage. As a result, the aforementioned uneven brightness along the tube axis can be prevented, and an approximately uniform brightness distribution can be obtained.

In addition, although the curved portion 1A is not shown in the figure, it is installed in the reflector lamp box provided on the inner surface of the lamp frame 2, that is, in the effective light-emitting area, so that as shown in the curve in FIG. 2, the curved portion of each EEFL1 The temperature difference between the 1A side and the electrode 3 side is reduced, and mercury concentration can be prevented. As a result, the occurrence of pink discharge can be suppressed. In addition, by forming the electrode 5 on the bent portion 1A of each C-shaped tube EEFL1, the light of the bent portion 1A can be blocked, so as shown in FIG. 3 , the brightness of each EEFL1 bent portion 1A can be reduced, and the backlight panel surface The brightness on the screen is uneven.

In addition, the C-shaped tube EEFL is used in the above-mentioned embodiment, but the U-shaped tube EEFL can also be used instead. In addition, the cross-sections of these C-shaped tubes and U-shaped tubes are not only circular, but also Oval flat tubes can also be used. In addition, since the C-shaped tube EEFL is used in this embodiment, the curved part is called a "curved part", and when the U-shaped tube EEFL is used, a common name is also used for the connection part called "short side part". , called the 'bend part'. These also apply to other embodiments described below.

second embodiment

4 and 5 show a backlight according to a second embodiment of the present invention. The characteristics of the structure of this embodiment are: a plurality of C-shaped tubes EEFL1 are arranged separately, so that the tube ends of the curved part 1A and the rubber lamp holder 4 with the internal external electrode 3 are located at different positions from each other, and on the back of the lamp frame 2 Two inverters 7 are arranged on both sides, and a transformer 6 for applying an opposite-phase rectangular wave voltage or a sine wave voltage to the external electrodes 3 at each end is provided at a position close to the external electrodes 3 of each lamp tube. In addition, in FIGS. 4 and 5 , elements common to those of the first embodiment shown in FIG. 1 are denoted by the same reference numerals. In this way, in the second embodiment, since the plurality of C-shaped tubes EEFL1 are alternately arranged in opposite directions, the positions of the external electrodes 3 that increase the temperature and brightness of the bent portion 1A are alternately exchanged, so the tube axis direction The temperature difference and board brightness difference can be reduced.

third embodiment

Hereinafter, a backlight according to a third embodiment of the present invention will be described with reference to FIG. 6 . The characteristic of the third embodiment is that, compared with the first embodiment shown in FIG. 1 , the rectangular wave voltage or the sine wave voltage applied to the rubber lamp sockets 4 at both ends of each C-shaped tube EEFL1 is in phase.

That is to say, in the backlight of this embodiment, multiple C-shaped tubes EEFL1 are arranged side by side in the lamp frame 2, and the external electrodes 3 at each end of each EEFL1 are mounted on the internal electrode or conductive rubber lamp holder 4. The external electrode 3 is provided on the bent portion 1A of each EEFL 1 and connected to GND. The bent portion 1A of each EEFL 1 is located in the effective light emitting region. Furthermore, a power supply circuit is formed, and this circuit applies a rectangular wave voltage or a sine wave voltage of the same phase to the rubber sockets 4 at both ends of each EEFL 1 through the common transformer 6 from the inverter 7. The circle 11 in the figure shows the applied voltage waveform.

In the backlight configured as described above, since the same-phase alternating voltage is applied to the external electrodes 3 at both ends of the lamp, no potential difference is generated between the two electrodes. Therefore, current leakage between the electrodes, which occurs when alternating voltages of different phases are applied to both electrodes, does not occur. Therefore, the luminance distribution and temperature distribution during light emission are almost the same as those of the first embodiment. As a result, the occurrence of pink discharge can be suppressed, and the unevenness of luminance on the surface of the backlight 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 an anti-phase voltage. On the other hand, in the case of the third embodiment, the advantage is that they can be shared. At least 1 transformer 6.

In addition, in the above-mentioned embodiment, the C-shaped tube EEFL is used, but the U-shaped tube EEFL can also be used instead. In addition, the cross-sections of these C-shaped tubes and U-shaped tubes are not only circular, but also An oval flat tube may be used.

Fourth Embodiment

Hereinafter, a backlight according to a fourth embodiment of the present invention will be described with reference to FIGS. 7 to 9 . The feature of this embodiment is the intermittent lighting function of the elbow type EEFL 1 having multiple lamps. As shown in Figure 7, the structure of EEFL1 is to coat phosphor on the inner wall of the glass tube, seal a small amount of Ar gas, Ne gas and mercury after making the inside of the glass tube negative pressure, seal both ends of the glass tube, and A solder layer about 20 mm long made of metal such as Sn and Ag is formed on both ends of the tube as electrodes 3 . The film thickness of the electrode 3 is set to 0.5 to 2 μm, and the shape of the lamp itself is C-shaped. The outer diameter of the glass tube can correspond to φ2.4mm to φ4mm. In addition, in the bent tube type EEFL 1 used in this embodiment, external electrodes 5 having the same electrode material as the external electrodes 3 at both ends are formed on the outer wall of the lamp tube at the bent portion 1A. The external electrodes 5 of the bent portion 1A have an electrode length twice that of the external electrodes 3 at both ends of the lamp tube. This is because the current flowing through the bent portion 1A is twice the current flowing through both ends of the lamp tube, so to improve its durability, the length of the electrode is doubled to increase the surface area.

The driving method of EEFL1 adopted in this embodiment is to apply a 40kHz to hundreds of kHz in-phase sine wave voltage to the external electrodes 3 at both ends of the lamp, and apply the anti-phase sine wave voltage at the same frequency as that applied to both ends of the lamp tube. Applied to the electrode 5 of the bent portion 1A. According to this method, it is safe to use electrically, and an EEFL that does not generate corona discharge and ozone can be realized with a tube length of more than 800 mm and an outer diameter of φ4 mm or less, which has not been possible until now. In addition, instead of the C-bend type EEFL1, the U-bend type EEFL1 shown in FIG. 8 may be used. At this time, the dimensions, electrode length, thickness, etc. are the same as those of FIG. 7 .

The configuration of a backlight in which multiple lamps of the above-mentioned elbow type EEFL 1 are intermittently lit will be described below with reference to FIG. 9 . In the backlight of this embodiment, the transformer 6 is used to apply a rectangular wave voltage or a sine wave voltage to the electrodes 3 at both ends of each elbow EEFL 1 and the electrode 5 of the bent portion 1A, so that the multi-lamp elbow EEFL 1 is discharged. glow.

For the convenience of description, in order to distinguish the EEFL1 with multiple lamps, the labels are sequentially set as 1-1, 1-2, ..., and in order to distinguish the straight pipe parts of each EEFL1, the straight pipe parts on both sides of EEFL1-1 are respectively marked with 1-11 , 1-12 labels for representation. In addition, the transformers that apply the voltage to the electrodes 3 in order to light the straight pipe parts are also marked with 6-11, 6-12, 6-13, ... to show the difference. In addition, the transformers for applying voltage to the electrodes of the bent portion 1A of each EEFL1 are also marked with reference numerals 6-21, 6-22, 6-23, . . . for distinction.

Now, the driving method of the backlight in the above-mentioned embodiment will be described. A voltage of the same voltage and frequency (from tens of kHz to hundreds of kHz) as the external electrodes 3 and 3 at both ends of the lamp tube is applied with an opposite phase to the external electrode 5 formed on the bent portion 1A of each EEFL 1 . The voltage applied to the electrodes 3 at both ends of the lamp tube is used as an electrical safety design, and its waveform is in phase. Therefore, the output electric signal is variable by means of an IC or the like arranged in the circuit, and a voltage is sequentially applied to the electrodes 3 at both ends. In this way, the intermittent driving of the straight pipe portions 1-11, 1-12, 1-21, 1-22... of each EEFL 1 can be realized sequentially.

In addition, in order to change the brightness of the backlight source itself, instead of intermittently driving the straight tube part, the EEFL1 of the whole lamp should be intermittently driven. Same as above, apply the same voltage as that applied to the external electrodes 3 at both ends of the lamp tube, and then apply the voltage to the external electrodes 3 at both ends of the lamp tube, so that the entire lamp can also be driven intermittently once.

In addition, the backlight which is an embodiment of the present invention has been described as an example above, but the present invention is widely applicable to lighting devices having the same configuration but having different uses.

Claims (7)

1. A lighting device, which is a lighting device in which a plurality of curved tube fluorescent lamps are arranged side by side. One or more rare gases, or mercury and one or more rare gases, seal both ends of the glass tube, and form a curved part in the middle of the glass tube, characterized in that, external electrodes are formed at both ends and the bent portion of the bent tube fluorescent lamp, Applying an antiphase rectangular wave voltage or a sine wave voltage to the external electrodes at the two ends respectively, and the external electrodes of the curved part are connected to GND. 2. The lighting device according to claim 1, characterized in that, The plurality of bent-tube fluorescent lamps are arranged side by side in a reflector light box forming a light frame, and the curved portion is arranged in the reflector light box, that is, in the effective light-emitting area. 3. The lighting device according to claim 2, characterized in that, The multiple curved tube fluorescent lamps are configured such that the positions of the external electrodes at both ends and the external electrodes of the bent portion are alternately located on opposite sides, and the rectangular wave voltage or sine wave voltage is applied to these multiple curved tube fluorescent lamps The inverter circuits used are scattered and arranged on both sides of the back side of the lamp frame. 4. The lighting device according to claim 3, characterized in that, The curved tube fluorescent lamp is in the shape of a C-shaped tube or a U-shaped tube. 5. A lighting device, which is a lighting device in which a plurality of curved tube fluorescent lamps are arranged side by side. One or more rare gases, or mercury and one or more rare gases, seal both ends of the glass tube, and form a curved part in the middle of the glass tube, characterized in that, external electrodes are formed at both ends and the bent portion of the bent tube fluorescent lamp, Apply the same-phase rectangular wave voltage or sine wave voltage to the external electrodes at the two ends respectively, and the external electrodes of the bent part are connected to GND. 6. The lighting device according to claim 5, characterized in that, The plurality of bent-tube fluorescent lamps are arranged side by side in a lamp frame with a reflector inside, and the curved part is arranged in the area where the reflector is placed, that is, the effective light-emitting area. 7. The lighting device according to claim 6, characterized in that, The curved tube fluorescent lamp is in the shape of a C-shaped tube or a U-shaped tube.

Images