JP5909884B2 - Discharge lamp lighting device - Google Patents

Description

  The present invention relates to a discharge lamp lighting device used for lighting a discharge lamp using dielectric barrier discharge.

  For example, in the process of manufacturing semiconductor elements, flat panel displays such as liquid crystal display devices, solar cells, etc., in general, in order to form a thin film with high adhesion to a substrate such as a silicon wafer or glass substrate, Contaminants such as organic substances existing on the surface of the substrate are removed by performing the cleaning process, and the method of cleaning the surface of the substrate is a photo-cleaning method that does not use water or an organic solvent. Is widely used. In such a light cleaning method, for example, a light source that emits vacuum ultraviolet rays having a wavelength of 200 nm or less is used, and as a light source that emits vacuum ultraviolet rays, a discharge lamp using dielectric barrier discharge is known.

In such a discharge lamp, it is necessary to apply a high frequency high voltage between the electrodes of the discharge lamp in order to generate a dielectric barrier discharge in the discharge vessel. As a device, a device including a step-up transformer that generates a high potential difference between a primary winding and a secondary winding is used (see Patent Document 1 and Patent Document 2).
In recent years, the light intensity required for the discharge lamp has been increased, and accordingly, the boosting ratio of the boosting transformer in the lighting device is required to be a high level of, for example, 10 times or more.

JP 2005-78928 A JP 2005-39092 A

  However, a discharge lamp using dielectric barrier discharge has a specific problem that the luminous efficiency of the lamp decreases as the step-up ratio of the step-up transformer in the lighting device increases. This is because the higher the step-up ratio of the step-up transformer, the slower the rise of the voltage generated in the secondary winding, which is contrary to the property of efficiently generating excimer molecules due to a steep voltage change.

  The present invention has been made based on the above circumstances, and an object of the present invention is to increase the step-up ratio of a step-up transformer in a discharge lamp lighting device used for lighting a discharge lamp using dielectric barrier discharge. An object of the present invention is to provide a discharge lamp lighting device capable of lighting a discharge lamp with high luminous efficiency even when the discharge lamp is large.

The discharge lamp lighting device of the present invention is a discharge lamp lighting device used for lighting a discharge lamp using dielectric barrier discharge.
A step-up transformer for applying a high-frequency high voltage between the electrodes of the discharge lamp;
The step-up transformer includes a plurality of transformer units each including a primary winding and a secondary winding corresponding to the primary winding set to a step-up ratio of 4 to 11.65 ,
Each primary winding of the transformer unit is connected in parallel with each other, and each secondary winding of the transformer unit is connected in series with each other,
A rectangular wave high frequency voltage is input to each primary winding of the transformer ,
The total boost ratio of each transformer in the boost transformer is 10-30 .

According to the discharge lamp lighting device of the present invention, the step-up transformer has a plurality of transformers, the primary windings of the transformers are connected in parallel to each other, and the secondary windings of the transformers Are connected in series with each other, and a rectangular high frequency voltage is input to each primary winding of the transformer, so that the total boost ratio of each transformer is the boost ratio of the boost transformer, By setting each step-up ratio low, a voltage change with a steep rise can be obtained in each of the transformer units. Therefore, even if the total boost ratio of the transformer section, that is, the boost ratio of the boost transformer is large, excimer molecules are efficiently formed in the discharge lamp by obtaining a voltage change with a steep rise in the boost transformer, As a result, the discharge lamp can be lit with high luminous efficiency.

It is explanatory drawing which shows the structure in an example of the discharge lamp lighting device of this invention with a discharge lamp. It is sectional drawing for description which shows the structure of the discharge lamp lighted by the discharge lamp lighting device of this invention, (a) is a longitudinal cross-sectional view, (b) is a cross-sectional view. It is a graph which shows the voltage waveform of the output electric power by the discharge lamp lighting device which concerns on Example 1 and Comparative Example 1. FIG. 3 is a graph showing a current waveform of output power by the discharge lamp lighting device according to Example 1 and Comparative Example 1. It is a graph which shows the relationship between the electric power input into the full bridge circuit of a discharge lamp lighting device, and the electric power input into a discharge lamp. It is a graph which shows the relationship between the electric power thrown into a discharge lamp, and the illumination intensity of a discharge lamp. With the discharge lamp lighting device of the present invention, the illuminance value and the step-up ratio when the discharge lamp is turned on under the condition that the applied power is 420 W and when the discharge lamp is turned on under the condition that the applied power is 630 W. It is a graph which shows a relationship.

Hereinafter, embodiments of the discharge lamp lighting device of the present invention will be described.
FIG. 1 is an explanatory view showing a configuration of an example of a discharge lamp lighting device of the present invention together with a discharge lamp. This discharge lamp lighting device (hereinafter, also simply referred to as “lighting device”) 10 is for lighting a discharge lamp 30 using dielectric barrier discharge, and is a full-scale converter that converts a DC voltage _VDC into a high-frequency voltage. The bridge circuit 15 and the step-up transformer 20 that steps up the high-frequency voltage output from the full-bridge circuit 15 and applies a high-frequency high voltage between one electrode 32 and the other electrode 33 in the discharge lamp 30 are configured.

  The full bridge circuit 15 includes four switching elements Q1 to Q4 connected in a bridge shape. Each of these switching elements Q1 to Q4 is driven by operating corresponding driving circuits G1 to G4, and switching elements Q1 and Q4 and switching elements Q2 and Q3 arranged diagonally to each other are alternately turned on. By setting the state, a rectangular high frequency voltage is generated between the connection point of the switching elements Q1 and Q2 and the connection point of the switching elements Q3 and Q4, and this high frequency voltage is output from the full bridge circuit 15.

  The step-up transformer 20 is provided with two transformers 21 and 25 including primary windings 22 and 26 and secondary windings 23 and 27 corresponding to the primary windings 22 and 26 respectively set to a predetermined step-up ratio. The primary winding 22 of the section 21 and the primary winding 26 of the other transformer section 25 are connected to the full bridge circuit 15 in parallel with each other, and the secondary winding 23 of the one transformer section 21 and the other The secondary windings 27 of the transformer unit 25 are connected in series with each other, and the secondary winding 23 of one transformer unit 21 is electrically connected to one electrode 32 of the discharge lamp 30 and the other transformer unit. The 25 secondary windings 27 are electrically connected to the other electrode 33 of the discharge lamp 30.

The step-up ratio of the step-up transformer 20, that is, the sum of the step-up ratio of one transformer 21 and the step-up ratio of the other transformer 25 is preferably 10-30, more preferably 14-20. When the sum of the boost ratios is too small, the discharge lamp 30 does not light uniformly because the boost cannot be sufficiently performed. On the other hand, when the total boost ratio is excessive, for example, the stray capacitance on the secondary windings 23 and 27 side viewed from the primary windings 22 and 26 side becomes large, and the steep rise of the output waveform is hindered. As a result, the luminous efficiency decreases.
Further, the step-up ratio of one transformer 21 and the step-up ratio of the other transformer 25 may be the same or different.
Moreover, it is preferable that the step-up ratio of each of the one transformer 21 and the other transformer is 4 to 10.

2A and 2B are cross-sectional views for explaining the configuration of a discharge lamp that is turned on by the lighting device of the present invention, in which FIG. 2A is a vertical cross-sectional view and FIG. The discharge lamp 30 emits light using dielectric barrier discharge, and has a discharge vessel 31 that forms a discharge space S in which an excimer gas is hermetically sealed. The discharge vessel 31 includes a rectangular upper wall portion 31a and a lower wall portion 31b that face each other, and four side wall portions 31c, 31d, 31e, and 31f that connect the peripheral edges of the upper wall portion 31a and the lower wall portion 31b. It is a flat box-shaped thing, and the whole is made of a material excellent in ultraviolet ray transmission having a wavelength of, for example, 200 nm or less.
One electrode 32 having a mesh shape is provided on the outer surface (upper surface in FIG. 2) of the upper wall portion 31a in the discharge vessel 31, and the outer surface (lower surface in FIG. 2) of the lower wall portion 31b in the discharge vessel 31 is provided in a mesh shape. The other electrode 33 is provided, and one electrode 32 and the other electrode 33 are electrically connected to the lighting device 10 shown in FIG.
Further, a light reflecting film 35 is formed on the entire inner surface of each of the upper wall portion 31a and the four side wall portions 31c, 31d, 31e, 31f and the inner surface of the peripheral portion of the lower wall portion 31b in the discharge vessel 31 so as to cover them. Has been.

As a material constituting the discharge vessel 31, a material that can transmit vacuum ultraviolet rays satisfactorily, specifically, silica glass such as synthetic quartz glass, sapphire glass, or the like can be used.
As a material constituting the one electrode 32 and the other electrode 33, a metal material having corrosion resistance such as gold, silver, copper, nickel, chromium, or the like can be used. The one electrode 32 and the other electrode 33 can be formed by screen-printing a conductive paste containing the above metal material or by vacuum vapor deposition of the above metal material.
The thickness of each of the one electrode 32 and the other electrode 33 is, for example, 0.1 μm to several tens of μm.
As a material constituting the light reflecting film 35, a material made of silicon oxide, aluminum oxide, zirconium oxide, or the like can be used. For example, a material made of silica particles and alumina particles, particularly, a content ratio of silica particles is 30 to 30%. 99% by mass and the content of alumina particles is preferably 1 to 70% by mass.

As the excimer gas sealed in the discharge vessel 31, for example, an excimer that emits vacuum ultraviolet rays, specifically, a rare gas such as xenon, argon, or krypton, or a rare gas and bromine, A mixed gas in which a halogen gas such as chlorine, iodine, or fluorine is mixed can be used. When a specific example of the excimer gas is shown together with the wavelength of emitted ultraviolet light, it is 172 nm for xenon gas, 191 nm for a mixed gas of argon and iodine, and 193 nm for a mixed gas of argon and fluorine.
Moreover, the sealing pressure of the excimer gas is, for example, 10 to 100 kPa.
Moreover, the fluorescent substance layer may be formed in the inner surface of the discharge vessel 31, and this can radiate | emit the fluorescence by the said fluorescent substance layer.

In the above lighting device, when a DC voltage V _DC is input from a DC power supply (not shown), the full bridge circuit 15 converts the DC voltage to a high frequency voltage, and the high frequency voltage output from the full bridge circuit 15 is converted by the step-up transformer 20. The voltage is boosted to generate a high frequency high voltage.
In the discharge lamp 30, the high frequency high voltage output from the step-up transformer 20 is applied between the one electrode 32 and the other electrode 33, so that a dielectric is formed in the discharge space S in the discharge vessel 31. Barrier discharge is generated, and excimer molecules derived from the excimer gas are formed by the dielectric barrier discharge, thereby generating, for example, ultraviolet light L having a wavelength of 200 nm or less. This ultraviolet light L is directly or directly applied to the light reflecting film 35. The light is reflected and emitted downward from the lower wall portion 31b of the discharge vessel 31.

  Thus, according to the lighting device 10 described above, the step-up transformer 20 includes the two transformers 21 and 25, and the primary windings 22 and 26 of the transformers 21 and 25 are connected in parallel to each other. At the same time, since the secondary windings 23 and 27 of the transformers 21 and 25 are connected in series with each other, the sum of the boost ratios of the transformers 21 and 25 becomes the boost ratio of the boost transformer 20. By setting the step-up ratio of each of the transformers 21 and 25 to be low, a voltage change with a steep rise is obtained in each of the transformers 21 and 25. Therefore, even if the sum of the step-up ratios of the transformers 21 and 25, that is, the step-up ratio of the step-up transformer 20 is large, a voltage change with a steep rise is obtained in the step-up transformer 20 and thereby the discharge vessel 31 of the discharge lamp 30 Excimer molecules are efficiently formed in the inside, and as a result, the discharge lamp 30 can be lit with high luminous efficiency.

The lighting device of the present invention is not limited to the above embodiment, and various modifications can be made.
For example, the step-up transformer may have three or more transformers as long as each primary winding is connected in parallel with each other and each secondary winding is connected in series with each other. .
Moreover, a full bridge circuit is not essential.
Moreover, the structure which has various circuits, such as a half bridge circuit and a flybag circuit, other than a full bridge circuit may be sufficient.

  Hereinafter, although the specific Example of the lighting device of this invention is described, this invention is not limited to the following Example.

<Example 1>
According to the configuration shown in FIG. 1, a discharge lamp lighting device A having a step-up transformer a having the following specifications was produced.
[Specifications of step-up transformer a]
Specifications of one transformer and the other transformer:
Primary winding: A winding formed by winding a core wire made of a strip-like body in which three bundle wires each having a diameter of 0.06 mm are bundled and fixed in parallel.
Number of turns of primary winding: 9 turns Secondary winding: A winding made by winding a core wire composed of 7 strands each made of 7 strands of 0.08 mm.
Number of turns of primary winding: 76 turns Boost ratio: 8.44 (the sum of the boost ratios of one transformer section and the other transformer section is 16.88)
Core: “EER-90” manufactured by JFE Ferrite Co., Ltd.

<Example 2>
In the step-up transformer a, the number of turns of the secondary winding in each of the one transformer unit and the other transformer unit is 65 and the boost ratio is 7.2 (the total of the boost ratios of the one transformer unit and the other transformer unit is 14). A discharge lamp lighting device B having the same configuration as in Example 1 was manufactured except that the step-up transformer b has the same specifications as the step-up transformer a except for .4).

<Example 3>
In the step-up transformer a, the number of secondary windings in each of the one transformer unit and the other transformer unit is 72, and the boost ratio is 8.0 (the total of the boost ratios of the one transformer unit and the other transformer unit is 16). 0.0), a discharge lamp lighting device C having the same configuration as in Example 1 was manufactured except that the step-up transformer c was changed to the step-up transformer c having the same specifications as the step-up transformer a.

<Example 4>
In the step-up transformer a, the number of turns of the secondary winding in each of the one transformer unit and the other transformer unit is 90 and the boost ratio is 10 (the sum of the boost ratios of the one transformer unit and the other transformer unit is 20). A discharge lamp lighting device D having the same configuration as that of Example 1 was manufactured except that the step-up transformer d having the same specification as that of the step-up transformer a was changed except for some cases.

<Example 5>
In the step-up transformer a, the number of turns of the secondary winding in each of the one transformer unit and the other transformer unit is 105 and the step-up ratio is 11.65 (the sum of the step-up ratios of the one transformer unit and the other transformer unit is 23). A discharge lamp lighting device E having the same configuration as in Example 1 was produced except that the step-up transformer e was changed to a step-up transformer e having the same specifications as the step-up transformer a except for.

<Comparative example 1>
A discharge lamp lighting device F having the same configuration as in Example 1 was produced except that the step-up transformer a was changed to a step-up transformer f having the following specification having a single transformer.
[Specifications of step-up transformer e]
Primary winding: A winding formed by winding a core wire made of a bundle of 2310 strands each having a diameter of 0.08 mm.
Number of turns of primary winding: 9 turns Secondary winding: A winding made by winding a core wire composed of 7 strands each made of 7 strands of 0.08 mm.
Number of turns of primary winding: 130 turns Boost ratio: 14.4
Core: “EER-120” manufactured by JFE Ferrite Co., Ltd.

<Production of test discharge lamp>
According to the configuration shown in FIG. 2, a discharge lamp (1), a discharge lamp (2) and a discharge lamp (3) having the following specifications were produced.
[Discharge lamp (1)]
Dimensions of discharge vessel: total length 1200mm, width 25mm, height 10mm
Effective light emission length: 1100mm
Inclusion material: xenon gas [discharge lamp (2)]
Dimensions of discharge vessel: total length 2200mm, width 25mm, height 10mm
Effective light emission length: 2100mm
Inclusion material: xenon gas [discharge lamp (3)]
Dimensions of discharge vessel: total length 3200mm, width 25mm, height 10mm
Effective light emission length: 3100mm
Inclusion material: Xenon gas

<Characteristic evaluation test of lighting device>
[Test 1] 760 W DC power is input to each of the discharge lamp lighting device A according to the first embodiment and the discharge lamp lighting device F according to the first comparative example, and the voltage waveform and current waveform of the high-frequency power output from each are obtained. It was measured. The results are shown in FIG. 3 and FIG.
As is clear from the results shown in the figure, it was confirmed that the lighting device A according to Example 1 can obtain a voltage change with a steep rise.

[Test 2]
Using each of the discharge lamp lighting device A according to Example 1 and the discharge lamp lighting device F according to Comparative Example 1, electric power (hereinafter also referred to as “input power”) input to each of the discharge lamp lighting devices. The discharge lamp (1) was turned on by changing the power, and the electric power (hereinafter also referred to as “lamp input power”) input to the discharge lamp (1) and the illuminance of the discharge lamp (1) were measured. Here, the illuminance of the discharge lamp (1) was measured by placing an illuminometer at a position 25 mm away from the outer surface of the discharge vessel in a nitrogen atmosphere. The results are shown in FIG. 5 and FIG.
5 is a graph showing the relationship between the power (chipper power) input to the full bridge circuit 15 of the discharge lamp lighting device shown in FIG. 1 and the power input to the discharge lamp (lamp input power). These are the graphs which show the relationship between the electric power input into the discharge lamp (lamp input electric power) and the illuminance of the discharge lamp.
From the results shown in FIG. 5, according to the discharge lamp lighting device A according to Example 1, the lamp input power increases as the input power increases. However, in the discharge lamp lighting device F according to Comparative Example 1, the input power It is understood that when the input power is 600 W or more, the lamp input power hardly increases even if the input power increases.
Further, from the results shown in FIG. 6, according to the discharge lamp lighting device A according to Example 1, if the lamp input power is up to about 700 W, the illuminance of the discharge lamp increases as the lamp input power increases. In the discharge lamp lighting device F according to Comparative Example 1, it is understood that the lamp input power is about 600 W, and the illuminance of the discharge lamp decreases.

[Test 3]
Using the discharge lamp lighting device B to the discharge lamp lighting device E according to Examples 2 to 5, the discharge lamp (1) to the discharge lamp (3) are turned on under the conditions that the lamp input power is 420 W and 630 W. The relationship between the illuminance value of the lamp and the step-up ratio of the step-up transformer in the discharge lamp lighting device was investigated. Here, the illuminance value of the discharge lamp was measured at a position 10 mm away from the outer surface of the discharge vessel in a nitrogen atmosphere by an illuminance meter “UIT-250” (172 nm) manufactured by USHIO INC.
FIG. 7 shows the illuminance value and the step-up ratio when the discharge lamp (2) is lit under the condition that the input power is 420 W and when the discharge lamp (2) is lit under the condition that the input power is 630 W. It is a graph which shows the relationship. From the results of FIG. 7, it is understood that high luminous efficiency can be obtained if the step-up ratio is 14 to 20. Further, although not shown, the same tendency was obtained for the discharge lamp (1) and the discharge lamp (3).
Thus, according to the discharge lamp lighting device of the present invention, it can be seen that high luminous efficiency can be obtained when the boost ratio is 10 to 30, and higher luminous efficiency is obtained particularly when the boost ratio is 14 to 20.

DESCRIPTION OF SYMBOLS 10 Discharge lamp lighting device 15 Full bridge circuit 20 Step-up transformer 21 Transformer part 22 Primary winding 23 Secondary winding 25 Transformer part 26 Primary winding 27 Secondary winding 30 Discharge lamp 31 Discharge vessel 31a Upper wall part 31b Lower wall part 31c, 31d, 31e, 31f Side wall portion 32 One electrode 33 The other electrode 35 Light reflecting films Q1 to Q4 Switching elements G1 to G4 Drive circuit

Claims (1)

In a discharge lamp lighting device used for lighting a discharge lamp using dielectric barrier discharge,
A step-up transformer for applying a high-frequency high voltage between the electrodes of the discharge lamp;
The step-up transformer includes a plurality of transformer units each including a primary winding and a secondary winding corresponding to the primary winding set to a step-up ratio of 4 to 11.65 ,
Each primary winding of the transformer unit is connected in parallel with each other, and each secondary winding of the transformer unit is connected in series with each other,
A rectangular wave high frequency voltage is input to each primary winding of the transformer ,
The discharge lamp lighting device characterized in that the total boost ratio of each transformer in the step-up transformer is 10-30 .

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