JP2004311449A - Rare gas discharge lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rare gas discharge lamp with an improved attachment property to an automobile meter panel or the like, or capable of reducing flickers at light dimming. <P>SOLUTION: The rare gas discharge lamp is equipped with a plurality of rare gas discharge bulbs 1 having a pair of external electrodes 13a, 13b on an outer peripheral surface of a glass bulb 12 with rare gas sealed inside, and a single discharge lamp lighting device 14 driving simultaneously by impressing a unipolar pulse on an external electrode of each rare gas discharge bulb. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rare gas discharge lamp suitable for, for example, a backlight of an automotive instrument panel, and more particularly to a rare gas discharge lamp which reduces flickering at the end of a tube or the like during dimming.

  Conventionally, as an example of this type of rare gas discharge lamp, for example, a phosphor film is applied to almost the entire inner peripheral surface of a glass bulb in which a rare gas such as xenon (Xe) is sealed, while the bulb is coated. A configuration is known in which a pair of tape-like external electrodes made of aluminum or the like are attached to the outer peripheral surface over substantially the entire length.

  In this conventional rare gas discharge lamp, a discharge is generated between a pair of external electrodes to generate a positive column in the bulb diameter direction to excite the rare gas and emit light.

  In the rare gas discharge lamp thus configured, for example, one external electrode is connected to the low-potential output terminal of the pulse lighting circuit connected to the DC power supply, and the other external electrode is connected to the high-potential output terminal. Then, pulse lighting is performed at, for example, 32 KHz by a pulse from the pulse lighting circuit.

  The use of such a conventional rare gas discharge lamp for an automobile instrument panel or the like is being studied. On the other hand, the conventional rare gas discharge lamp has a problem in that the positive column converges in a thread shape at the end of the tube (end of the bulb) and runs at random, forming bright and dark stripes and causing flicker.

  That is, according to the experiment of the present inventor, when this rare gas discharge lamp is lit at the dimming frequency of 104 Hz and the lighting frequency of 32 KHz, when the dimming rate is about 93%, the high potential (H) side is already set. Flickering occurred at the tube end of the other external electrode, and when the dimming rate was reduced to about 73%, flickering also occurred at the tube end of one external electrode on the low potential (L) side. Furthermore, when the dimming rate was reduced to 33%, the entire bulb 2 flickered.

  Therefore, the present invention has been made in view of such circumstances, and an object thereof is to reduce a rare gas discharge lamp with improved mountability to an automobile meter panel or the like, or to reduce flickering during dimming. It is to provide a rare gas discharge lamp.

  In the rare gas discharge lamp of the present invention, a plurality of discharge lamps having a pair of external electrodes provided on an outer peripheral surface of a glass bulb in which a rare gas is sealed, and a monopolar pulse is applied to each external electrode of these discharge lamps. And a single discharge lamp lighting device that is driven simultaneously.

  The present inventor conducted experiments on various rare gas discharge lamps in order to investigate the cause of flicker of the conventional rare gas discharge lamp. FIG. 3 is a front view showing an embodiment of the rare gas discharge lamp, and FIG. 4 is a conceptual diagram showing a state in which a pulse lighting circuit 5 is connected to the rare gas discharge lamp of FIG.

  The rare gas discharge lamp 1 is, for example, a glass bulb 2 bent in an arc shape corresponding to the shape of an automotive meter panel, and the bulb 2 is filled with only a rare gas such as xenon (Xe). The bulb 2 has a phosphor film coated on almost the entire inner peripheral surface thereof, and a pair of tape-like external electrodes 3a and 3b made of aluminum or the like are provided on the outer peripheral surface of the bulb 2 on the arcuate inner and outer peripheral portions. Are attached over substantially the entire length, and both ends of the pair of external electrodes 3 a and 3 b in the longitudinal direction are almost coincident in the diameter direction of the bulb 2 and terminated. The rare gas discharge lamp 1 has an inner peripheral external electrode 3 a connected to a lower potential output terminal L of a pulse lighting circuit 5 connected to a DC power supply 4, and an outer peripheral external electrode 3 b connected to a higher potential output terminal H. These are connected to each other, and pulse lighting is performed by a pulse from the pulse lighting circuit 5. As a result, a new finding is that the flicker is caused by the fact that the lengths of the pair of external electrodes 3a and 3b are substantially equal, and both ends in the longitudinal direction are terminated so as to be mutually coincident in the diameter direction of the bulb 2. Got. The present invention is configured based on this new finding.

  According to the present invention, a plurality of rare gas discharge lamps can be simultaneously turned on by a single rare gas discharge lamp lighting device.

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

  FIGS. 1A to 1D are front views respectively showing a plurality of embodiments of the present invention, and FIG. 1A shows an example of a best mode.

  That is, as shown in FIG. 1A, the rare gas discharge lamp 11 is formed by bending a glass bulb 12 into an arc shape corresponding to the shape of an automobile meter panel, for example. ) And only a rare gas of He, Ne, Kr, or Ar is sealed at 100 to 120 Torr.

  The bulb 12 has a phosphor film coated on almost the entire inner peripheral surface, and a pair of aluminum tape-shaped external electrodes 13a and 13b are attached to the arc-shaped inner and outer peripheral portions of the outer peripheral surface of the bulb 12. I'm wearing

  In other words, the inner peripheral side external electrode 13a is attached over substantially the entire length of the arc-shaped inner peripheral portion of the bulb 12, and its longitudinal ends are almost coincident with the inner peripheral side ends of the bulb 12 and terminated. I have.

  On the other hand, the outer peripheral side external electrode 13b is formed to be slightly shorter than the entire length of the arc-shaped outer peripheral portion of the bulb 12, and both ends in the longitudinal direction are terminated so as to be slightly shorter than the inner peripheral side external electrode 13b by La. I have.

  Then, one end of the outer peripheral side external electrode 13b is connected to the high potential side output terminal H of the rare gas discharge lamp lighting device 14 shown in FIG. 2, and one end of the inner peripheral side external electrode 13a is connected to the low potential side output terminal L. The rare gas discharge lamp 11 is turned on by applying a unipolar pulse voltage between the pair of external electrodes 13a and 13b.

  As shown in FIG. 2, the rare gas discharge lamp lighting device 14 includes a DC power supply 15, a switching element 16 including a transistor for chopping the DC from the DC power supply 15 at, for example, 100 Hz to 1000 KHz, and a chopping of the switching element 16. A dimming control circuit 17 for controlling and dimming light by a predetermined on-duty; a transformer 18 for oscillating a monopolar pulse from the switching element 16 at a lighting frequency of, for example, 20 to 50 KHz and boosting the voltage to a high voltage; , And a control circuit 20 for controlling the switching. The one end of the outer peripheral side external electrode 13b is connected to each of the high potential side output terminals H of the transformer 18, while the low potential side output terminal L is connected. Is connected to one end of the inner peripheral side external electrode 13a.

  Therefore, a high potential of a monopolar pulse is applied to the outer peripheral electrode 13b of the rare gas discharge lamp 11, while a lower potential of a monopolar pulse is applied to the inner peripheral electrode 13b.

  For this reason, discharge occurs between the inner and outer peripheral outer electrodes 13a and 13b, and a positive column is generated in the diameter direction over substantially the entire length of the bulb 12, thereby exciting the rare gas to emit light.

  When the rare gas discharge lamp 11 is lit at a dimming frequency of, for example, 104 Hz and a lighting frequency of 32 KHz, the flicker occurs at the axial middle portion of the bulb 12 when the dimming rate is about 20%. When the dimming rate is about 13%, flickering starts to occur at the tube ends on both sides of the inner and outer peripheral outer electrodes 13a and 13b, and the whole eventually begins to flicker.

  That is, when the dimming rate exceeded about 20%, almost no flickering of the rare gas discharge lamp 11 was found.

  The rare gas discharge lamp 21 shown in FIG. 1B has an inner peripheral side outer electrode 23 a slightly shorter than the entire length on the inner peripheral side of the arc-shaped bulb 22, while the outer peripheral side of the bulb 22 has the same. The outer electrode 23b is formed over substantially the entire length, and a high potential (H) is applied to the inner electrode 23a and a low potential (L) is applied to the outer electrode 23b. This is the same as the embodiment shown in FIG.

  The flicker of the rare gas discharge lamp 21 when the rare gas discharge lamp 21 is operated under the same conditions as in the above-described embodiment, that is, at a dimming frequency of 104 Hz and a lighting frequency of 32 KHz, has a dimming rate of about 41%. Sometimes, flickering occurs at the tube end of the inner peripheral external electrode 23a on the high potential side, and when the dimming rate is reduced to 30%, flickering occurs substantially at the center of the bulb 22, and the dimming rate further increases. When the pressure was reduced to about 21%, flickering occurred in almost the entire valve 22.

  That is, according to the rare gas discharge lamp 21, when the dimming rate exceeds about 41%, the flicker can be reduced to such a degree that almost no flicker can be found.

  The rare gas discharge lamp 31 shown in FIG. 1 (C) has an inner peripheral external electrode 33a formed on the inner peripheral side of the arcuate bulb 32 over substantially the entire length thereof, while the outer peripheral side of the bulb 32 has the entire length thereof. An outer peripheral external electrode 33b slightly shorter than La is formed, and a high potential (H) is applied to the inner peripheral external electrode 33a and a low potential (L) is applied to the outer peripheral external electrode 33b.

  When the rare gas discharge lamp 31 is lit under the same conditions as in the above embodiments, when the dimming rate is about 66%, flickering occurs at the tube ends on both sides of the inner and outer peripheral electrodes 33a and 33b. When the dimming rate was reduced to about 57%, almost the entire bulb 32 flickered.

  That is, according to the rare gas discharge lamp 31, when the dimming rate exceeded about 66%, almost no change was found.

  The rare gas discharge lamp 41 shown in FIG. 1D has an inner peripheral side outer electrode 43a slightly shorter than the entire length on the inner peripheral side of the arc-shaped bulb 42, and on the outer peripheral side of the bulb 42. The outer peripheral side outer electrode 43b is formed over substantially the entire length, and a low potential (L) is applied to the inner peripheral side outer electrode 43a and a high potential (H) is applied to the outer peripheral side external electrode 43b.

  When the rare gas discharge lamp 41 is turned on under the same conditions as in the above embodiments, the flicker occurs at the tube ends on both sides of the pair of external electrodes 43a and 43b when the dimming rate is about 80%. The flickering began to occur, and when the dimming rate was reduced to about 21%, flickering occurred almost entirely in the bulb 42.

  That is, according to the rare gas discharge lamp 41, almost no flicker could be found when the dimming rate exceeded about 80%.

  Therefore, according to each of the above embodiments, the dimming rate is about 93%, and the flickering starts to occur at the tube ends of the pair of external electrodes 3a and 3b as compared with the conventional rare gas discharge lamp 1. Has been found to be able to be reduced.

  In each of the embodiments described above, the case where two rare gas discharge lamps 11 to 41 are simultaneously lit and light is controlled by the single rare gas discharge lamp lighting device 14 shown in FIG. 2 is described. However, the present invention is not limited to the number of lights. In addition, the valves 12 to 42 are not limited to the arc shape, and are not limited to the shape.

  Further, the pair of external electrodes 13a, 13b, 23a, 23b, 33a, 33b, 43a, 43b is not limited to an aluminum tape, but may be a copper tape or a material obtained by baking copper and carbon in a paste. .

(A)-(D) are front views respectively showing each embodiment of the rare gas discharge lamp according to the invention of claim 2. FIG. 2 is a circuit diagram of a rare gas discharge lamp lighting device for lighting each rare gas discharge lamp shown in FIG. 1. The front view which shows one Example of the rare gas discharge lamp concerning the invention of Claim 1. FIG. 4 is a conceptual diagram showing a state where a pulse lighting device is connected to the rare gas discharge lamp of FIG. 3.

Explanation of reference numerals

11, 21, 31, 41 Noble gas discharge lamps 12, 22, 32, 42 Bulbs 13a, 13b, 23a, 23b, 33a, 33b, 43a, 43b A pair of inner and outer electrodes 14 Rare gas discharge lamp lighting device 15 DC power supply 16 Switching element 17 Dimming control circuit 18 Transformers 19a, 19b A pair of switching elements 20 Transformer driving control circuit

Claims (1)

A plurality of discharge lamps with a pair of external electrodes provided on the outer peripheral surface of a glass bulb filled with a rare gas inside, and a single discharge lamp lighting that applies a unipolar pulse to each external electrode of these discharge lamps and drives them simultaneously A rare gas discharge lamp, comprising:

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