JP2009059645A - Discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of steadily keeping light emission of a metal halide lamp of an emission light wavelength of 800 mm or longer. <P>SOLUTION: The discharge lamp lighting device related to the present invention is equipped with a metal halide lamp 52 of an emission light wavelength of 800 mm or longer having an air-tight luminous tube filled with rare gas, mercury and thallium iodide as discharging media and discharging electrodes provided at both longitudinal ends of an arc tube, and an electronic ballast 542 to supply a square wave voltage and a current to the discharging electrodes 521 and 522 of the metal halide lamp. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device.

  A metal halide lamp in which a rare gas, mercury, iron, and thallium iodide are sealed as a discharge medium in an airtight arc tube, and discharge electrodes are installed at both ends in the tube axis direction of the arc tube. Since it can emit ultraviolet light having a high light emission intensity, it is useful as a light source used for curing a UV curable coating and for photoreaction on a functional polymer film that has been recently marketed.

  However, such a metal halide lamp has a problem in that light emission from mercury and thallium iodide is separated during lighting, and arc fluctuation is likely to occur depending on the lamp length.

  This arc swing is a phenomenon in which the arc during discharge does not become straight but swells with respect to the lamp axis direction. When this arc sway occurs, the lamp voltage fluctuates, and the arc tube bulges due to a rise in arc tube temperature.

Acoustic resonance is known as a cause of arc fluctuation. In the lamp, the input is periodically increased or decreased depending on the frequency of the power supply voltage, and a rough wave (dense when the input increases, coarse when the input decreases) is generated by plasma (mercury vapor) from the arc toward the lamp tube wall. At the same time, a reflected wave that is reflected by the tube wall and returned to the lamp tube wall is generated. When these two waves interfere with each other, a standing wave whose pressure distribution does not change with time is generated. When such a standing wave is generated, non-uniform pressure in the lamp tube makes the arc state unstable and causes arc fluctuation (bending).
Japanese Patent Laid-Open No. 06-275234

  The present invention has been made in view of the above technical problem, and provides a discharge lamp lighting device capable of stably lighting a metal halide lamp having a light emission length of 800 mm or more without causing an arc fluctuation. Objective.

  The present invention includes a metal halide lamp having an emission length of 800 mm or more, in which a rare gas, mercury, and thallium iodide are sealed as a discharge medium in an airtight arc tube, and discharge electrodes are installed at both ends in the tube axis direction of the arc tube. A discharge lamp lighting device comprising an electronic ballast that supplies a rectangular wave voltage and current to the discharge electrode of the metal halide lamp.

  According to the discharge lamp lighting device of the present invention, by supplying a rectangular wave voltage and current to a metal halide lamp having a light emission length of 800 mm or more with an electronic ballast, fluctuations in input voltage and current on the time axis can be made uniform. The light emission of the lamp can be maintained stably.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. A discharge lamp lighting device according to one embodiment of the present invention will be described with reference to FIG. 52 is a metal halide lamp which is an ultraviolet (UV) discharge lamp, and is made of, for example, a refractory metal such as tungsten, molybdenum and tantalum, or a metal such as stainless steel and titanium inside a quartz arc tube 520 having ultraviolet transparency. The electrodes 521 and 522 are arranged, and sockets 523 and 524 are respectively provided outside. As an example of the specification of the metal halide lamp 52, the outer tube diameter is 27.5 mm, the wall thickness is 1.5 mm, the light emission length L is 1000 mm, the lamp voltage is 1100 V, and the lamp current value is 11.0 A. In the present invention, the light emission length L of the arc tube 520 can be L ≧ 800 mm.

  The arc tube 520 contains a rare gas having an argon (Ar) gas pressure of 10 Torr (about 13.3322 Pa), mercury of 1.68 mg / cc or less, and thallium iodide (TlI) of 0.012 mg / cc or less. . Thallium iodide has a large emission peak in the vicinity of wavelengths 352 nm, 365 nm, and 378 nm, particularly in the vicinity of wavelengths 352 nm and 378 nm.

  Thallium (Tl) has a strong emission line spectrum in the wavelength region of 352 nm, 365 nm, and 378 nm, and has the effect of reducing the emission intensity of mercury. Therefore, it suppresses the mercury emission of 313 nm and has a wavelength range of 340 to 400 nm. Ultraviolet light having relatively increased light emission can be emitted. Therefore, when the metal halide lamp 52 of the present embodiment is used in a process of forming an alignment film on a glass plate by irradiating ultraviolet rays in the production of a liquid crystal panel to polymerize an ultraviolet reactive material, a wavelength that greatly affects the characteristics of the liquid crystal panel. Irradiation of ultraviolet rays having a region of 340 nm or less can be reduced.

  The lighting circuit 54 in the discharge lamp lighting device of the present embodiment includes an AC power supply 541 and an electronic ballast 542 that applies a voltage and current of the AC power supply 541 to a stable rectangular wave and is applied to both end electrodes 521 and 522 of the metal halide lamp 52. It is composed of. That is, the sockets 523 and 524 at both ends of the metal halide lamp 52 are attached to the power supply side sockets 531 and 532, respectively, and the power supply is supplied to the power supply side sockets 531 and 532.

  A detailed configuration of the electronic ballast 542 is shown in FIG. The electronic ballast 542 includes a power input terminal 61 for the AC power supply 541, an input filter 62 for suppressing a surge voltage, a full-wave rectifier 63 for rectifying AC, a low-frequency filter 64 for a rectified current, and DC-DC conversion into a predetermined voltage DC. A DC / DC converter 65 for switching polarity, a polarity switch 66 for switching polarity, an output filter 67 for output current, and an igniter 68, and output terminals HV 1 and HV 2 for lamp connection are connected to the igniter 68. A cooling fan 69 is also provided.

  On the other hand, in order to electronically control the electronic ballast 542, a control power supply 71, a DC / DC converter 65, a polarity switch 66, an analog control circuit 72 for controlling the cooling fan 69, a microcomputer control circuit 73, an operation panel circuit 74 is provided. Further, the microcomputer control circuit 73 is connected to an input / output signal connector 75.

  In the discharge lamp lighting device of the present embodiment, the electronic ballast 542 converts the alternating current of the alternating current power source 541 into a rectangular wave voltage and a rectangular wave current of a predetermined frequency, and discharge electrodes at both ends of the metal halide lamp 52. By supplying power to 521 and 522, this is discharged.

  According to the discharge lamp lighting device of the present embodiment, as described above, the electronic ballast 542 feeds the rectangular wave voltage and current to the metal halide lamp 52 having a light emission length of 800 mm or more, whereby the input voltage on the time axis is supplied. The current fluctuation can be made uniform, and the light emission of the metal halide lamp 52 can be stably maintained.

  In an arc tube having an outer tube diameter of 27.5 mm, a wall thickness of 1.5 mm, and a light emission length L of 800 mm, an argon (Ar) gas pressure of 10 Torr (about 13.3322 Pa), a rare gas, mercury of 1.68 mg / cc or less, A metal halide lamp containing 0.012 mg / cc or less of thallium iodide (TlI) was lit by applying a rectangular wave voltage and current with a frequency of 100 Hz with an electronic ballast, but stable lighting without arc fluctuation was achieved. Could be maintained. FIG. 3A shows a no-load lamp voltage waveform at start-up, and FIG. 3B shows a lamp current waveform immediately after lighting. FIG. 4 shows a lamp current waveform during lighting, which shows that a stable lamp current is obtained during lighting.

[Comparative Example 1]
As in Example 1, Hg, Fe, Sn, and HgI ₂ were sealed inside an arc tube having an outer tube diameter of 27.5 mm, a wall thickness of 1.5 mm, and a light emission length L of 800 mm, and an Ar gas pressure of 10 Torr (about 13 Torr). .3322 Pa) metal halide lamp was lit by applying a sine wave voltage and current with a frequency of 50 Hz with a choke coil ballast, but arcing occurred and stable lighting could not be obtained.

  In an arc tube having an outer tube diameter of 27.5 mm, a wall thickness of 1.6 mm, and a light emission length L of 1300 mm, an argon (Ar) gas pressure of 10 Torr (about 13.3322 Pa), a rare gas, mercury of 1.68 mg / cc or less, A metal halide lamp containing 0.032 mg / cc or less of thallium iodide (TlI) was lit by applying a rectangular wave voltage and current with a frequency of 100 Hz with an electronic ballast, but stable lighting without arc fluctuation Could be maintained. FIG. 5 shows the lamp current waveform during lighting, which shows that a stable lamp current is obtained during lighting.

[Comparative Example 2]
The same metal halide lamp as in Example 2 was lit by applying a sine wave voltage and current of 50 Hz with a choke coil ballast, but arcing occurred and stable lighting could not be obtained.

The block diagram of the discharge lamp lighting device of one embodiment of the present invention. The block diagram of the electronic ballast in the said embodiment. FIG. 3 (a) is a no-load lamp voltage waveform diagram at the start of Example 1 of the present invention, and FIG. 3 (b) is a lamp current waveform diagram immediately after lighting of Example 1. The lamp current waveform figure in the lighting of Example 1 of this invention. The lamp current waveform figure in lighting of Example 2 of this invention.

Explanation of symbols

52 ... Metal halide lamp 520 ... Arc tube 521, 522 ... Electrode 523, 524 ... Socket 54 ... Lighting circuit 541 ... AC power source 542 ... Electronic ballast

Claims (1)

A metal halide lamp having a light emission length of 800 mm or more, in which a rare gas, mercury and thallium iodide are sealed as a discharge medium in an airtight arc tube, and discharge electrodes are installed at both ends in the tube axis direction of the arc tube;
A discharge lamp lighting device comprising: an electronic ballast that supplies a rectangular wave voltage and current to the discharge electrode of the metal halide lamp.

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