KR20060034618A - Dielectric barrier discharge lamp, dielectric barrier discharge equipment and method of using them - Google Patents

Abstract

Disclosed is a dielectric barrier discharge lamp wherein a pair of electrodes are arranged in a discharge vessel which is filled with a discharge gas. The discharge gas contains Xe and Ar, and the partial pressure of Xe relative to the total pressure of Xe and Ar in the discharge vessel is not less than 0.20 and not more than 0.80.

Description

DIELECTRIC BARRIER DISCHARGE LAMP, DIELECTRIC BARRIER DISCHARGE EQUIPMENT AND METHOD OF USING THEM}

The present invention relates to a dielectric barrier discharge lamp, a dielectric barrier discharge device, and a method of using the same.

As a dielectric barrier discharge lamp, what filled Xe (xenon) etc. in the discharge container is widely known (for example, refer Unexamined-Japanese-Patent No. 8 (1996) -87989).

In a lamp using a vacuum ultraviolet ray whose center wavelength emitted from the Xe ₂ excimer is 172 nm, the light output is not necessarily sufficient, and therefore, higher output is required.

Of course, when the pressure of Xe charged in the discharge vessel is increased, one Xe ^* atom (* means electron excited state) in an excited state and two Xe atoms in a state having a bottom part Since the density of the Xe ₂ excimer produced by the three-body collision reaction (Xe ^* + Xe + Xe → Xe ₂ + Xe) occurring in between increases, the light output of 172 nm increases. However, as the pressure increases, the probability of electrons colliding with Xe atoms, Xe ⁺ ions, etc. increases. As a result, even if electrons get energy from the electric field, the energy loss due to the collision increases. Therefore, since the average energy of electrons falls, ionization efficiency (the number of times to ionize Xe atoms while an electron advances in unit length) falls. This means that the voltage (lamp start-up voltage) necessary for starting the discharge increases, and accordingly, improvement of a power supply device or the like is necessary. Therefore, increasing the sealing pressure in pure Xe gas was not an effective method. Due to such circumstances, conventionally, only a dielectric barrier discharge lamp whose product of the total pressure in the discharge vessel and the discharge gap length is 2250 Torr · mm or less has been used. Therefore, there was a problem that sufficient light output could not be obtained.

This invention is made | formed in view of the above circumstances. That is, in a lamp using a gas-sealed discharge container containing Xe, it is an object of the present invention to provide a dielectric barrier discharge lamp and a dielectric barrier discharge device in which light output is increased without an increase in lamp starting voltage. to be.

The present inventors earnestly studied to develop a dielectric barrier discharge lamp and a dielectric barrier discharge apparatus in order to solve this problem. As a result, the discharge gas to be filled in the discharge vessel is a mixed gas of Xe and Ar, and the Xe partial pressure ratio P _Xe / (P _Xe + P _Ar ) to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less. It has been found that the radiation intensity can be improved by not increasing the lamp starting voltage.

This invention is made | formed according to this knowledge. That is, the first invention according to the present invention is a dielectric barrier discharge lamp in which a pair of electrodes are provided in a discharge container filled with discharge gas, wherein the discharge gas contains Xe and Ar, and Xe and Ar in the discharge container. Xe partial pressure ratio with respect to the total pressure of is 0.20 or more and 0.80 or less, It is characterized by the above-mentioned.

According to a second aspect of the present invention, there is provided a dielectric barrier discharge lamp including a dielectric barrier discharge lamp having a pair of electrodes provided in a discharge vessel filled with discharge gas, and a power supply device for applying an alternating voltage between the electrodes. The gas contains Xe and Ar, and the Xe partial pressure ratio to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less.

According to the present invention, the discharge gas is a mixed gas of Xe and Ar, and the Xe partial pressure ratio P _Xe / (P _Xe + P _Ar ) to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less. The radiation intensity can be improved without involving the increase in the lamp starting voltage.

1 is a cross-sectional view of a dielectric barrier discharge apparatus having a dielectric barrier discharge lamp in accordance with one embodiment of the present invention.

Figure 2 is a graph showing the relationship between the total pressure of the filling gas and the emission intensity (UV 172nm).

3 is a graph showing the relationship between the total pressure of the filling gas and the minimum ramp starting peak voltage.

4 is a graph showing the relationship between the partial pressure ratio and the maximum sealing pressure.

5 is a graph showing the relationship between the partial pressure ratio and the maximum radiation intensity (UV 172 nm) that can be designed.

In the following, the present invention will be described in more detail with reference to Examples.

1 shows a dielectric barrier discharge device, which is an embodiment of the present invention. This dielectric barrier discharge apparatus is provided with the dielectric barrier discharge lamp 10 (henceforth only the "lamp 10"), and the inverter apparatus 20. As shown in FIG. The lamp 10 includes, for example, a discharge vessel 11 made of synthetic quartz (for example, a size of about 350 mm x about 40 mm x about 13 mm and a thickness of about 2 mm), and in the discharge space 13 that is inside thereof. The discharge gas is filled. In the discharge vessel 11, a pair of electrodes 14 and 15 are formed. Since the electrode 15 is a mesh type, light emitted by the discharge can be transmitted. The inverter device 20 is connected between these two electrodes 14 and 15 via the transformer 27. The inverter device 20 is connected to the primary coil 27P of the transformer 27, and both electrodes 14 and 15 of the lamp 10 are connected to the secondary coil 27S of the transformer. The transformer 27 and the inverter device 20 constitute an excimer power supply 30.

In the lamp of the above configuration, the central wavelength emitted from the Xe ₂ excimer molecule shows the emission intensity of the spectrum of 172 nm. In radiation of ultraviolet-ray, the discharge gap length was about 9 mm. The value of this discharge gap length is calculated | required by subtracting about 4 mm which is twice the thickness of a discharge container from about 13 mm of thickness (equivalent to the distance between electrodes) of a discharge container. Peak voltage at the time of lamp start-up is applied between the electrodes (lamp start-up peak voltage) V _sp to 16kV, the peak voltage applied between the electrodes (during lit) after start-up (ramp-peak voltage), V _p the 6kV, the frequency f 30kHz It was set as a schedule. The applied voltage waveform was a rectangular wave of 0.5 Hz in both rising and falling. Further, the total pressure (sealing pressure) of the Xe-Ar mixed gas in the discharge vessel 11 is changed, and the partial pressure ratio (P _Xe / (P _Xe + P _Ar ) of the Xe-Ar mixed gas is also changed at the respective total pressures. )) Was made into eight types of 0.10, 0.15, 0.20, 0.35, 0.50, 0.70, 0.80, 1.00. In addition, radiation intensity, using a vacuum ultraviolet spectrometer and a photomultiplier tube (增倍管), was measured under N ₂ atmosphere.

From this result, it was found that even at any partial pressure ratio (P _Xe / (P _Xe + P _Ar ) = 0.10 to 1.00), the radiation intensity increased by increasing the total pressure (sealing pressure) of the mixed gas. This is because the density of the Xe ₂ excimer molecule increases with an increase in the total pressure (sealing pressure). In addition, it was found that, on the condition that the total pressure (sealing pressure) was constant, almost the same radiation intensity could be obtained in the partial pressure ratio range of 0.50 to 1.00.

Next, in each partial pressure ratio P _Xe / (P _Xe + P _Ar ), when the total pressure (sealing pressure) is changed, the minimum peak voltage necessary for starting the lamp, that is, the minimum lamp starting peak voltage V _{sp We} reviewed how _min changes.

As shown in FIG. 3, it was found that V _{sp min} increased by increasing the total pressure (sealing pressure) at any partial pressure ratio. And this is similar to Paschen's law in flame discharge. The Parsen law is a theory that the voltage (flame voltage) for starting the magnetic flux discharge is expressed as a function of the product pd of the sealing pressure p and the discharge gap length d. The spark voltage is minimized at any pd value. In general, in a region where the pd value is larger than the point where the spark discharge is minimized (Passen minimum), the spark voltage also increases as the pd value increases. The range of the total pressure shown in FIG. 3 corresponds to this area.

As shown in Fig. 3, V _{sp min} is increased by increasing the partial pressure of Ar from 0 to 0.80, that is, by decreasing the partial pressure ratio (P _Xe / (P _Xe + P _Ar )) from 1.00 to 0.20. It turned out that it is reduced. However, it was found that V _{sp min} becomes the _minimum at the partial pressure ratio (P _Xe / (P _Xe + P _Ar )) at 0.20, and increases when the partial pressure ratio is made small.

The above results are summarized as follows. As the total pressure (sealing pressure) of the mixed gas in the discharge space is increased, the radiation intensity increases (see FIG. 2), and V _{sp min} also increases. In addition, V _{sp min} falls when the partial pressure ratio (P _Xe / (P _Xe + P _Ar )) is decreased from 1.00 to 0.20, and the partial pressure ratio is taken as minimum at 0.20 (see FIG. 3).

By the way, with respect to the power supply of a lamp, the voltage which can be supplied is restrict | limited because of the cost, size, etc. restrictions. Therefore, it is required not only to increase the radiation intensity of a lamp but also to be able to start a lamp without raising the peak voltage _Vsp applied between electrodes at the time of lamp start-up.

Thus, studies were made to provide a lamp capable of increasing the radiation intensity without raising V _sp .

Fig. 4 is a graph showing the maximum sealing pressure at which the discharge can be started with respect to the partial pressure ratio of the mixed gas when the peak voltage V _sp applied between the electrodes at the start of the lamp is made constant. 4 is derived from the graph of FIG. 3.

Specifically, the graph of FIG. 4 can be derived as follows from FIG. 3. Here, the case of V _sp = 8 kV will be described as an example. First, the intersection between the broken line shown in Fig. 3 and nine graph lines (lines of the partial pressure ratio 0.00 to 1.00), specifically, the partial pressure ratio 1.00, 0.80, 0.70, 0.50, 0.35, 0.20, 0.15, 0.10, 0.00 The total pressure value in the case of is obtained (and these values represent the maximum sealing pressure at which the lamp can be started at V _sp = 8 kV in each partial pressure ratio). The nine data thus obtained were plotted on the graph with the partial pressure ratio on the x-axis and the maximum sealing pressure on the y-axis. From the graph of this FIG. 4, it turned out that the maximum sealing pressure takes the maximum value in the partial pressure ratio of 0.2 vicinity.

Next, from the graph of FIG. 4 and the graph of FIG. 2 obtained in this way, the maximum designable radiation intensity at V _sp = 8 kV and V _p = 6 kV is obtained as shown in FIG. 5.

According to FIG. 5, it turns out that a radial intensity becomes the maximum in the vicinity of partial pressure ratio 0.40. In addition, when the partial pressure ratio is in the range of 0.20 or more and 0.80 or less, it can be seen that the radiation intensity is remarkably increased as compared with a lamp in which 100% of the conventional Xe is sealed. Thus, where the partial pressure within the range of the range, preferably, more than 0.27 to less than 0.7 or less than 0.20, 0.80, without accompanying an increase in the V _sp, in other words if a constant V _sp, can enhance the emission intensity I knew there was.

When the discharge gap length was about 9 mm, in the conventional example in which only Xe was used as the discharge gas, only the dielectric barrier discharge lamp in which the total pressure of the discharge gas was 250 Torr or less could be used. This can be understood more from the result when the partial pressure ratio of Xe in FIG. 3 is 1.00. That is, in the conventional dielectric barrier discharge lamp, only the product whose total pressure of the discharge gas and the discharge gap length are 250 Torr x 9 mm = 2250 Torr mm or less has been used. In contrast, when Ar is mixed with Xe as in the present invention, a region in which the total pressure of the discharge gas is 350 Torr or more can be used (see FIGS. 2 and 3). In other words, the product of the total pressure of the discharge gas and the discharge gap length can be one of 350 Torr x 9 mm = 3150 Torr mm or more. In the present invention, by combining the Xe partial pressure ratio with respect to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less, and the product of the total pressure of the discharge gas and the discharge gap length is 3150 Torr.mm or more. The radiation intensity can be particularly remarkably improved without accompanying a rise in starting voltage. In the present invention, when the discharge gap length is about 9 mm, the total pressure of the discharge gas is preferably 400 Torr or more (see Fig. 3). That is, it is preferable that the product of the total pressure of discharge gas and discharge gap length is 400 Torr * 9mm = 3600 Torr * mm or more.

As a result, according to the present invention, it is possible to simplify the design of a lamp that values radiation intensity and a power supply device (inverter, transformer, etc.).

<Other Example>

The present invention is not limited to the embodiments described by the above description and the drawings, for example, the following embodiments are also included in the technical scope of the present invention, and various modifications can be made without departing from the scope of the present invention as well as It can be carried out.

(1) In the above embodiment, the dielectric barrier discharge lamp 10 has a specific shape and a specific size, but the shape and size of the dielectric barrier discharge lamp are not particularly limited.

(2) In the above embodiment, but the specific discharge gap length figured displayed with respect to d, the frequency f, the peak voltage V _p, these values are not particularly limited. For example, it can be confirmed that the same effect can be obtained even when the value is changed in the range of d = 3 to 30 mm, f = 10 kHz to 240 kHz, and V _p = 2 kV to 24 kV.

(3) In the above embodiment, a specific voltage waveform is shown, but the voltage waveform is not particularly limited. For example, it can be confirmed that the same effect as that of a rectangular wave can be obtained when the sinusoidal wave is changed in the range of d = 3 to 30 mm, f = 10 kHz to 240 kHz, and V _p = 2 kV to 24 kV.

And when Hg coexists with Xe-Ar mixed gas as gaseous substance other than a rare gas, when the partial pressure of Hg at the time of lamp lighting is set to P _Hg and the total pressure of discharge gas is P, _{By setting} the ratio of _Hg / P to less than 0.001%, the effect of the present invention is greatly improved. This is for the following reason. The excitation energy of Hg is smaller than that of Xe. Therefore, since electron energy is preferentially consumed by the excitation of Hg, the number of Xe excited is greatly reduced. As a result, since the density of Xe2 excimer falls drastically, the light output of 172 nm falls drastically. On the other hand, in the case of further mixing of rare gases other than Xe and Ar, a decrease in ultraviolet intensity of 172 nm is hardly seen. Therefore, especially when Hg coexists, it is preferable to make ratio of P _Hg / P less than 0.001%. "The partial pressure ratio of mercury described in the Claim of this application is less than 0.001%" includes the case where no mercury is included at all.

This application is based on the JP Patent application 2004-026513 of an application on February 3, 2004, These content is referred here.

As described above, according to the present invention, the discharge gas is a mixed gas of Xe and Ar, and the Xe partial pressure ratio P _Xe / (P _Xe + P _Ar ) to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more, Moreover, by setting it as 0.80 or less, radiation intensity | strength can be improved, without raising a lamp starting voltage.

Claims (12)

A dielectric barrier discharge lamp provided with a pair of electrodes in a discharge vessel filled with discharge gas, And the discharge gas contains Xe and Ar, and the Xe partial pressure ratio to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less. The method of claim 1, An ultraviolet-ray having a center wavelength of 172 nm is used. The method of claim 1, The product of the total pressure of the said discharge gas and the discharge gap length of the said discharge container is 3150 Torr * mm or more, The dielectric barrier discharge lamp characterized by the above-mentioned. The method of claim 1, The product of the total pressure of the said discharge gas and the discharge gap length of the said discharge container is 3600 Torr * mm or more, The dielectric barrier discharge lamp characterized by the above-mentioned. The method according to any one of claims 1 to 4, The partial pressure ratio of mercury in the discharge gas to the total pressure of the discharge gas in the discharge vessel at the time of turning on the dielectric barrier discharge lamp is less than 0.001%. A dielectric barrier discharge device comprising a dielectric barrier discharge lamp provided with a pair of electrodes in a discharge vessel filled with discharge gas, and a power supply device for applying an AC voltage between the electrodes, And the discharge gas contains Xe and Ar, and the Xe partial pressure ratio to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less. The method of claim 6, An ultraviolet-ray having a center wavelength of 172 nm is used. The method of claim 6, The product of the total pressure of the said discharge gas and the discharge gap length of the said discharge container is 3150 Torr * mm or more, The dielectric barrier discharge lamp characterized by the above-mentioned. The method of claim 6, The product of the total pressure of the said discharge gas and the discharge gap length of the said discharge container is 3600 Torr * mm or more, The dielectric barrier discharge lamp characterized by the above-mentioned. The method according to any one of claims 6 to 9, The partial pressure ratio of mercury in the discharge gas to the total pressure of the discharge gas in the discharge vessel at the time of turning on the dielectric barrier discharge lamp is less than 0.001%. A method of using a dielectric barrier discharge lamp provided with a pair of electrodes in a discharge vessel filled with discharge gas, The discharge gas contains Xe and Ar, and the Xe partial pressure ratio to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less, A method of using a dielectric barrier discharge lamp using ultraviolet rays having a center wavelength of 172 nm generated from the dielectric barrier discharge lamp. A method of using a dielectric barrier discharge device comprising a dielectric barrier discharge lamp provided with a pair of electrodes in a discharge vessel filled with discharge gas, and a power supply device for applying an alternating voltage between the electrodes, The discharge gas contains Xe and Ar, and the Xe partial pressure ratio to the total pressure of Xe and Ar in the discharge vessel is 0.20 or more and 0.80 or less, And using ultraviolet rays having a center wavelength of 172 nm generated from the dielectric barrier discharge lamp.

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