JP2009206050A - Discharge lamp, and light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp high in emission intensity of vacuum ultraviolet light, capable of keeping high light emission intensity characteristics over a long time, and accordingly having excellent ultraviolet light resistance characteristics, and to provide a light emitting device. <P>SOLUTION: The discharge lamp includes a discharge vessel made of synthetic quartz glass, and emits light including ultraviolet light having a wavelength not larger than 190 nm in the discharge vessel. The discharge lamp is characterized in that the contents of fluorine in the synthetic quartz glass forming the discharge vessel is 7,000-30,000 wt.ppm at least in one part of the discharge vessel; the concentration of Si-F bonds in the synthetic quartz glass forming a surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming a thick center part at least on one-side surface; and the concentration of oxygen molecules in the synthetic quartz glass forming the surface layer of the surface is higher than that in the synthetic quartz glass forming the thick center part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a discharge lamp and a light emitting device, and in particular, in a discharge lamp, as a material that forms the entire discharge vessel or a part of a discharge vessel such as a window member for light emission, Discharge using a specific synthetic quartz glass with improved transmission characteristics on the short-wavelength side in vacuum ultraviolet light as a material for forming the entire light emission window or part of the light emission window such as a member of the light emission part The present invention relates to a lamp and a light emitting device.

Conventionally, discharge lamps that emit light including ultraviolet light, particularly vacuum ultraviolet light, have been widely used in various fields. For example, glass substrate cleaning apparatuses for liquid crystals using xenon excimer lamps and deuterium lamps are used. There are known vacuum ultraviolet spectroscopic measuring devices and the like.
In these discharge lamps, as a material for forming a part of the discharge vessel constituting the discharge lamp or a discharge vessel such as a window member for light emission, light is generally applied to light including vacuum ultraviolet light. Synthetic quartz glass, which is known as a material having permeability, is widely used.

  In recent years, for discharge lamps that emit such vacuum ultraviolet light, for example, it has been required to emit vacuum ultraviolet light at a higher output. The synthetic quartz glass itself has been improved in characteristics (see, for example, Patent Documents 1 to 4 and Non-Patent Document 1).

For example, in Patent Document 1, the spectral transmittance at a wavelength of 165 nm is set to 65% or more, and fluorine is further set to 200 to 10000 wt. A synthetic quartz glass is disclosed which is added at a concentration of ppm and contains hydrogen molecules at a rate of less than 5 × 10 ¹⁶ particles / cm ³ , and the applicability of the synthetic quartz glass to a discharge lamp or the like is shown. Has been.
Further, in Patent Document 2, as a material for forming a light-emitting container of an ultraviolet lamp having an emission spectrum with a wavelength of 200 nm or less, a spectral transmittance at a wavelength of 165 nm is 65% or more, and a fluorine concentration is 200 to 10,000 wt. ppm, and the OH group content is 10 wt. It is described that synthetic quartz glass having a ppm or less is used.
Patent Document 3 discloses a synthetic quartz glass having a fluorine concentration of 100 ppm or more, an OH group content of 100 ppm or less, and a fictive temperature of 1100 ° C. or less. It has been shown that it can be used as a material for forming sealed tubes such as low-pressure mercury lamps, excimer lamps, and deuterium lamps that emit light up to the vacuum ultraviolet region.
Furthermore, Patent Document 4 discloses a production method in which oxygen molecules are dissolved in silicon oxyfluoride glass containing at least 0.1% by weight of fluorine, and a VUV light transmissive glass obtained by this production method is disclosed. It is shown to be used as a material for forming a light emission window of a light emission device.

The synthetic quartz glass described in these patent documents 1 to 4 contains fluorine for the purpose of obtaining a high ultraviolet transmittance.
When such synthetic quartz glass containing fluorine is used as a material for forming a discharge vessel, the form of fluorine in the vicinity of the surface becomes unstable in a molded body obtained by molding the synthetic quartz glass. Therefore, the surface is etched. Specifically, as shown in FIG. 10, the discharge vessel is a process of manufacturing an ingot made of synthetic quartz glass (raw material) containing fluorine, and a process of forming the ingot into an intended shape (for example, a pipe shape). And it produces by passing through the process of performing the etching process on the surface of a molded object in this order.

As described above, the discharge vessel made of synthetic quartz glass containing fluorine undergoes a surface etching process so that, as shown in FIG. 11, in the thickness direction, Si—F bonds in the synthetic quartz glass are formed. The concentration is made uniform, whereby uniform UV resistance, that is, high UV transmittance can be obtained throughout the thickness.
Here, the graph of FIG. 11 is for a discharge vessel having a thickness of 2 mm (normal thickness is 1 to 2 mm), and the horizontal axis is the thickness of the discharge vessel (the value of “0” on the left end side). Indicates the outer surface, while the value “2000” on the right end side indicates the inner surface.), And the vertical axis indicates the fluorine content (concentration) and the oxygen atom concentration. In the figure, a straight line (A) indicates the fluorine content (concentration), and a straight line (C) indicates the concentration of oxygen atoms.

  In addition, the synthetic quartz glass described in Non-Patent Document 1 contains fluorine and is doped with oxygen, and a discharge vessel made of this synthetic quartz glass has a structure as shown in FIG. A process for producing an ingot made of synthetic quartz glass (raw material) containing fluorine, a process for forming an ingot into a desired shape (for example, a pipe shape), a process for optically polishing the surface of the molded body, and oxygen doping It is produced by performing a process of performing treatment (heating treatment at a heating temperature of 1000 to 1100 ° C. in an oxygen atmosphere) in this order.

JP 2005-306650 A JP 2005-310455 A JP 2001-019450 A JP-T-2004-530615 HD. Witzke, “172 nm excimer lamp irradiation of F-doped SiO 2 classes, with different pretlements compared with pure pure and Cl-doped glass, Plysics 200”. 43C2002, 155-158

However, even when the discharge lamp is configured using any of the synthetic quartz glasses described in Patent Document 1 to Patent Document 4 and Non-Patent Document 1, sufficient ultraviolet light resistance cannot be obtained. There was found.
Specifically, for example, a xenon excimer lamp will be described as an example. Inside the discharge vessel of the xenon excimer lamp, xenon excimer radiation is also emitted from the ultraviolet absorption edge of synthetic quartz glass having a wavelength of 145 to 160 nm. The light near the ultraviolet absorption edge is absorbed by the synthetic quartz glass forming the discharge vessel, resulting in a rise in the temperature of the discharge vessel.As a result, the ultraviolet absorption edge in the synthetic quartz glass is shifted to the longer wavelength side, A vicious cycle occurs in which the degree to which the excimer radiation of xenon is absorbed by the synthetic quartz glass further increases and the temperature of the discharge vessel further rises.
Then, the light near the ultraviolet absorption edge is absorbed by the synthetic quartz glass forming the discharge vessel, and the temperature of the discharge vessel rises due to this, so that the presence form of fluorine contained in the synthetic quartz glass Changes over time, and the light emission intensity cannot be stably maintained.
That is, in the synthetic quartz glass forming the discharge vessel, fluorine exists by forming a Si-F bond, but the synthetic quartz glass absorbs light near the ultraviolet absorption edge, thereby The Si—F bond existing in the vicinity of the surface is dissociated and fluorine is liberated, and accordingly, a Si—Si bond is formed. The presence of this Si-Si bond causes an absorption band with a maximum absorption wavelength of 163 nm, so that part of the light emitted inside the discharge vessel is absorbed by the synthetic quartz glass forming the discharge vessel. As a result, the emission of light from the excimer lamp is hindered, and the amount of light emitted from the excimer lamp (light emission intensity) is reduced, that is, the light emission intensity maintenance characteristic is deteriorated. Moreover, there is a problem that Si—Si bonds existing in the synthetic quartz glass cause ultraviolet distortion.

Thus, in the xenon excimer lamp, if the characteristics of the synthetic quartz glass itself forming the discharge vessel are improved simply by containing fluorine, the decrease (deterioration) of the light emission intensity maintaining characteristics is suppressed, High light emission intensity characteristics cannot be maintained over a long period of time.
Such a problem occurs not only in a xenon excimer lamp but also in a discharge lamp that emits light including vacuum ultraviolet light. Furthermore, not only a discharge lamp, but also a light emission having a configuration in which a discharge lamp that emits light including vacuum ultraviolet light is used as a light source and a light emission window made of synthetic quartz glass for emitting light from the discharge lamp is provided. Also in the apparatus, the light emitting window member disposed in the vicinity of the periphery of the discharge lamp is irradiated with light near the ultraviolet absorption edge radiated from the discharge lamp, and the heat from the discharge vessel of the discharge lamp is received. As a result, a similar problem occurs.

The present invention has been made based on the circumstances as described above, and its purpose is that the radiation intensity of vacuum ultraviolet light is high and high light radiation intensity characteristics can be maintained over a long period of time. Another object of the present invention is to provide a discharge lamp having excellent ultraviolet light resistance.
Another object of the present invention is to provide a light emitting device having high radiation intensity of vacuum ultraviolet light and capable of maintaining high light radiation intensity characteristics over a long period of time, and thus having excellent ultraviolet light resistance characteristics. There is to do.

The discharge lamp of the present invention comprises a discharge vessel made of synthetic quartz glass, and emits light containing ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel.
In at least a part of the discharge vessel, the content of fluorine in the synthetic quartz glass forming the discharge vessel is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, And the density | concentration of the oxygen molecule in the synthetic quartz glass which forms the surface layer of the said surface is higher than the density | concentration of the oxygen molecule in the synthetic quartz glass which forms a thickness center part, It is characterized by the above-mentioned.

In such a discharge lamp of the present invention, in the surface layer of the at least one surface of the discharge vessel, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is from the thickness center portion side to the surface. Changes in the thickness direction
It is preferable that the average concentration of oxygen molecules in the thickness portion from the at least one surface to a depth of 200 μm is 0.8 × 10 ¹⁶ molecules / cc or more.

The discharge lamp of the present invention comprises a discharge vessel made of synthetic quartz glass, and emits light containing ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel.
In at least a part of the discharge vessel, the content of fluorine in the synthetic quartz glass forming the discharge vessel is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, And the density | concentration of OH group in the synthetic quartz glass which forms the surface layer of the said surface is higher than the density | concentration of OH group in the synthetic quartz glass which forms thickness center part, It is characterized by the above-mentioned.

In such a discharge lamp of the present invention, in the surface layer of the at least one surface of the discharge vessel, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is from the thickness center portion side to the surface. Changes in the thickness direction
The average concentration of OH groups in the thickness portion from the at least one surface to a depth of 100 μm is 70 wt. It is preferably at least ppm.

The light emitting device of the present invention includes a discharge lamp that emits light including ultraviolet light having a wavelength of 190 nm or less inside a discharge vessel, and a light emission window made of synthetic quartz glass for emitting light from the discharge lamp. In a light emitting device comprising:
In at least a part of the light emission window, the fluorine content in the synthetic quartz glass forming the light emission window is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, And the density | concentration of the oxygen molecule in the synthetic quartz glass which forms the surface layer of the said surface is higher than the density | concentration of the oxygen molecule in the synthetic quartz glass which forms a thickness center part, It is characterized by the above-mentioned.

In such a light emitting device of the present invention, in the surface layer of the at least one surface in the light emitting window, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is from the thickness center portion side. It changes in the thickness direction toward the surface,
It is preferable that the average concentration of oxygen molecules in the thickness portion from the at least one surface to a depth of 200 μm is 0.8 × 10 ¹⁶ molecules / cc or more.

The light emitting device of the present invention includes a discharge lamp that emits light including ultraviolet light having a wavelength of 190 nm or less inside a discharge vessel, and a light emission window made of synthetic quartz glass for emitting light from the discharge lamp. In a light emitting device comprising:
In at least a part of the light emission window, the fluorine content in the synthetic quartz glass forming the light emission window is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, And the density | concentration of OH group in the synthetic quartz glass which forms the surface layer of the said surface is higher than the density | concentration of OH group in the synthetic quartz glass which forms thickness center part, It is characterized by the above-mentioned.

In such a light emitting device of the present invention, in the surface layer of the at least one surface of the light emitting window, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is outside the thickness center portion side. It changes in the thickness direction toward the surface,
The average concentration of OH groups in the thickness portion from the at least one surface to a depth of 100 μm is 70 wt. It is preferably at least ppm.

In the discharge lamp of the present invention, as the discharge vessel, the fluorine content of the synthetic quartz glass forming at least a part of the discharge vessel is optimized, and in the surface layer on at least one side thereof, the thickness center portion and Therefore, a material of a specific material in which at least one of the concentration of oxygen molecules and the concentration of OH groups is in a specific range is used together with the concentration of Si-F bonds in the synthetic quartz glass. Then, in a specific portion of such a discharge vessel, Si—F that can be a source of generation of Si—Si bonds by the action of light (light near the ultraviolet absorption edge) in the synthetic quartz glass forming the surface layer. The amount of fluorine present by forming a bond is reduced, and in accordance therewith, there is fluorine (fluorine molecule) in a free state, and in addition, at least one of oxygen molecule and OH group exists. Therefore, these actions suppress the decrease in the radiation intensity of vacuum ultraviolet light and the formation of Si—Si bonds, which are the cause of ultraviolet distortion, and thus the increase in the concentration of Si—Si bonds in synthetic quartz glass is suppressed. As a result, the excellent characteristics obtained by including fluorine itself in the synthetic quartz glass are maintained over a long period of time. The synthetic quartz glass that forms the light absorbs light in the vicinity of the ultraviolet absorption edge, so that the presence form of fluorine contained in the synthetic quartz glass changes with time, resulting in a light emission intensity maintaining characteristic. It can suppress that it falls.
Therefore, according to the discharge lamp of the present invention, the radiation intensity of vacuum ultraviolet light is high, and high light radiation intensity characteristics can be maintained over a long period of time, and thus excellent ultraviolet light resistance characteristics can be obtained. .

  Moreover, since the discharge vessel contains either one of oxygen molecules and OH groups at a specific concentration in the surface layer, the action of oxygen molecules or the action of OH groups can be reliably obtained. High ultraviolet light resistance can be reliably obtained, and a further excellent ultraviolet light resistance can be obtained for the discharge lamp.

  According to the light emitting device of the present invention, the fluorine content of the synthetic quartz glass forming at least a part of the light emitting window is optimized as the light emitting window, and the surface layer on at least one side thereof Due to the relationship with the thickness center, a material of a specific material in which at least one of the concentration of oxygen molecules and the concentration of OH groups is in a specific range is used together with the concentration of Si-F bonds in the synthetic quartz glass. Therefore, the same effect as the above-described discharge lamp of the present invention is obtained, and as a result, the radiation intensity of vacuum ultraviolet light is high, and high light radiation intensity characteristics can be maintained over a long period of time, Therefore, excellent ultraviolet light resistance can be obtained.

<Discharge lamp>
In the discharge lamp of the present invention, the fluorine content (concentration) of synthetic quartz glass forming the whole discharge vessel or a part of the discharge vessel such as a light emission window member is optimized as the discharge vessel, and In the surface layer on at least one side, the concentration of Si-F bonds in the synthetic quartz glass and at least one of the concentration of oxygen molecules and the concentration of OH groups are within a specific range from the relationship with the thickness center portion. A specific material is used, and the transmission characteristics on the short wavelength side in vacuum ultraviolet light are improved. In the following, the present invention will be described by taking a xenon excimer lamp as an example.

FIG. 1 is a cross-sectional view for explaining the outline of the configuration of an example of a xenon excimer lamp according to the present invention, and FIG. 2 is a cross-sectional view of the xenon excimer lamp shown in FIG. It is sectional drawing which shows a cross section.
The xenon excimer lamp (hereinafter, also simply referred to as “excimer lamp”) 20 includes a cylindrical outer tube 22 made of synthetic quartz glass, and the outer tube 22 disposed coaxially with the tube axis. A cylindrical inner tube 23 made of synthetic quartz glass having an outer diameter smaller than the inner diameter of the outer tube 22, and the outer tube 22 and the inner tube 23 are melt-bonded at both ends so that the outer tube 22 and the inner tube are joined. A discharge vessel 21 having a double tube structure in which an annular discharge space H that is airtightly closed is formed.
The outer tube 22 of the discharge vessel 21 has a mesh-like first electrode (hereinafter also referred to as “outer electrode”) 24 made of a conductive material such as a wire mesh, in close contact with the outer peripheral surface thereof. The inner tube 23 is in close contact with the inner peripheral surface of the inner tube 23, for example, a cylindrical shape (pipe shape) or a substantially C-shape having a notch in a part of the cross section ( A second electrode (hereinafter also referred to as “inner electrode”) 25 made of an aluminum plate having a bowl shape is provided. The outer electrode 24 and the inner electrode 25 are connected to a power supply device 26 made of, for example, a high frequency power source.
The discharge space H is filled with xenon gas, which is a discharge gas that forms excimer molecules by excimer discharge.
In the example of this figure, the inner electrode 25 has a cylindrical shape (pipe shape). Moreover, in FIG. 1, 27 is the remainder of the exhaust pipe used when enclosing gas in the discharge vessel 21 on manufacture.

In this excimer lamp 20, at least a part of the discharge vessel 21 made of synthetic quartz glass satisfies the following conditions (1) and (2), and also satisfies the conditions (3) or (4). is there.
The excimer lamp 20 according to the present invention is not limited as long as the discharge vessel 21 satisfies the conditions (1) and (2) and at least one of the conditions (3) and (4). It is preferable that all of the conditions (1) to (4) are satisfied.

(1) The synthetic quartz glass forming the discharge vessel 21 has a fluorine content of 7000 wt. ppm to 30000 wt. ppm or less.
(2) In the discharge vessel 21, the concentration of Si—F bonds in the synthetic quartz glass forming the surface layer on at least one side of the inner surface and the outer surface is such that the Si—F in the synthetic quartz glass forming the thickness center portion. Below the concentration of binding.
(3) In the discharge vessel 21, the concentration of oxygen molecules in the synthetic quartz glass that forms the surface layer on the at least one side is higher than the concentration of oxygen molecules in the synthetic quartz glass that forms the thickness center portion.
(4) In the discharge vessel 21, the concentration of OH groups in the synthetic quartz glass that forms the surface layer on the at least one side is higher than the concentration of OH groups in the synthetic quartz glass that forms the thickness center portion.

Here, in this specification, the “thickness center” refers to a region of 40% (in other words, ± 20%) of the center of the total thickness (total thickness) of the discharge vessel 21. For example, when the thickness of the discharge vessel 21 is 2 mm, a portion having a depth of 1 mm from the surface is the thickness center, and a region ± 0.2 mm (0.4 mm range) from the thickness center is the thickness center portion. Is done.
Further, the “surface layer” generally indicates a region from the surface of the discharge vessel to a depth of around 100 μm, but varies depending on the total thickness (total thickness) of the discharge vessel. The inside is defined as a region having a depth of 50 to 250 μm from the surface of the discharge vessel.

  Satisfying the above condition (1), that is, the fluorine content of the synthetic quartz glass forming the discharge vessel 21 is 7000 wt. ppm to 30000 wt. By setting it to ppm or less, a high ultraviolet transmittance can be obtained for the excimer lamp 20.

  As will be apparent from the experimental examples described later, when the fluorine content is too small, the radiation intensity of the vacuum ultraviolet light of the excimer lamp is reduced, and the lamp life (service life) is shortened. On the other hand, when the fluorine content is excessive, fluorine is deposited inside the discharge space, and a larger lamp voltage and lamp input are required to operate the excimer lamp in a predetermined state. Along with this, the temperature of the discharge vessel rises, the ultraviolet absorption edge shifts to the long wavelength side, the radiation intensity of vacuum ultraviolet light decreases, and ultraviolet light distortion due to the radiation of vacuum ultraviolet light is likely to accumulate, resulting in a short lamp life. Become.

  The fluorine content in the synthetic quartz glass can be measured by, for example, an ion chromatography method, an EPMA method (Electron Probe Micro-Analysis), a fluorescent X-ray spectroscopy method, a SIMS method (Secondary Ion Mass Spectrometry), and the like.

Satisfying the above condition (2), that is, in the discharge vessel 21, the concentration of Si—F bonds in the synthetic quartz glass forming the surface layer of one or both surfaces is determined by the Si—F bond concentration in the synthetic quartz glass forming the thickness center portion. By making the concentration lower than the −F bond concentration, it is possible to suppress the generation of an absorption band having a maximum absorption wavelength of 163 nm due to the presence of the Si—Si bond in the synthetic quartz glass forming the discharge vessel 21. High light emission intensity characteristics can be maintained over a long period of time.
The reason for this is that light in the vicinity of the ultraviolet absorption edge of the light emitted as xenon excimer radiation inside the discharge vessel 21 is absorbed by the synthetic quartz glass forming the discharge vessel 21, thereby causing the Si-F bond. This is because Si—Si bonds are formed, and the increase in the Si—Si bond concentration in the synthetic quartz glass due to this can be suppressed.
That is, in the surface layer on one or both surfaces of the discharge vessel 21, the portion having a low Si—F bond concentration (hereinafter also referred to as “specific surface layer portion”) is free without forming a Si—F bond. When the fluorine present in the released state is dissociated from the Si—F bond by the action of light (light near the ultraviolet absorption edge), the broken Si— It has a function as a “fluorine reservoir” that forms a new Si—F bond based on the F bond. In addition, the dissociation of the Si—F bond by the action of light is caused from the surface of the discharge vessel 21. Since it proceeds toward the thickness center (inner surface side), a specific surface layer portion having a low Si-F bond concentration is formed on at least one surface layer on the inner surface side and outer surface side of the discharge vessel 21. , Si-Si bond By keeping the concentration of it may Si-F bond and generating source is reduced, it is possible to reduce the absolute number of Si-Si bonds newly formed by the action of light.

  As will be apparent from the experiment described later, when the specific surface layer portion is not formed, that is, when the concentration of Si-F bonds related to the surface layers on both surfaces is equivalent to the thickness center portion, it is high over a long period of time. The light emission intensity characteristic cannot be obtained.

The specific surface layer portion in the discharge vessel 21 is formed in a region from the surface of the discharge vessel 21 to a depth of 50 to 250 μm.
In the example of this figure, the specific surface layer portion is in the region from the outer surface to a depth of 200 μm on the outer surface side of the discharge vessel 21 (specifically, the outer surface side of the outer tube 22 of the discharge vessel 21). Is formed.
In the discharge vessel having a complicated shape such as a double tube structure such as the discharge vessel 21 of the excimer lamp 20, the specific surface layer portion may be formed only on the outer tube serving as the light emitting portion. In this case, in the inner tube of the discharge vessel, the specific surface layer portion may be formed on either the inner surface side or the outer surface side, or may be formed on both sides.

  Specifically, the synthetic quartz glass forming the discharge vessel 21 has a substantially constant Si-F bond concentration at the center of the wall thickness, while the Si in the specific surface layer portion moves toward the surface. The concentration of Si—F bonds is changed so that the concentration gradient of −F bonds is small.

It is essential that such a portion having a low Si-F bond concentration (specific surface layer portion) is formed on at least one surface layer on the outer surface side and inner surface side of the discharge vessel 21, and most preferably It is preferable that specific surface layer portions are formed on the surface layers of both surfaces of the discharge vessel 21.
In the discharge lamp 20, in order to suppress absorption of light having a wavelength of 163 nm generated in the discharge space H (absorption by the synthetic quartz glass immediately after forming the discharge container 21), the surface layer on the inner surface side in the discharge container 21 is Although it is considered that the specific surface layer portion is formed as a theoretically preferable aspect, even if the specific surface layer portion is formed only on the outer surface side of the discharge vessel 21 (the outer surface side of the outer tube 22). As is clear from experimental examples described later, a sufficient effect can be obtained.

  Although it is difficult to actually measure the concentration of the Si—F bond in the synthetic quartz glass, for example, the Si—F bond has different optical characteristics from the Si—O bond (because of different absorption wavelengths). By utilizing the fact that the refractive index is different), the refractive index in the central portion of the thickness and the refractive index in the surface layer (specific surface layer portion) can be measured and confirmed based on the measured values.

In the discharge vessel 21 that satisfies the above condition (3), that is, the surface layer on the one or both surfaces (the surface relating to the surface layer on which the specific surface layer portion is formed, hereinafter also referred to as “specific surface”). By making the concentration of oxygen molecules in the synthetic quartz glass that forms the discharge vessel 21 higher than the concentration of oxygen molecules in the synthetic quartz glass that forms the thickness center portion, Since generation of an absorption band having a maximum absorption wavelength of 163 nm due to the presence of -Si bond can be suppressed, high light emission intensity characteristics can be maintained over a long period of time.
The reason for this is that when the Si-F bond is dissociated by the action of light (light near the ultraviolet absorption edge) due to the presence of oxygen molecules, a Si-O-Si bond is formed. -Si bond formation is inhibited, and as a result, formation of Si-Si bonds can be suppressed, and the absolute number of Si-Si bonds formed from Si-F bonds can be reduced. Because.
Further, as will be described later, by the presence of oxygen molecules, as a result, in the manufacturing process, the concentration of Si—Si bonds that are present along with decreasing the concentration of Si—F bonds is reduced. Can be small.

  As is clear from the experiment described later, the concentration of oxygen molecules on the surface layer of both surfaces is equivalent to the thickness center portion, that is, the concentration of oxygen molecules on the surface layer on the specific surface side is equivalent to the thickness center portion. In such a case, it is impossible to obtain high light emission intensity characteristics over a long period of time.

Specifically, on the specific surface side of the discharge vessel 21, the concentration of oxygen molecules in the synthetic quartz glass forming the surface layer is 0.8 × in the thickness portion from the specific surface to a depth of 200 μm. It is preferable that it is 10 ¹⁶ pieces / cc or more, and that the average concentration is 5.0 × 10 ¹⁶ pieces / cc or more on the outermost surface consisting of the thickness portion up to a depth of 50 μm from the specific surface. Particularly preferred.

As described above, when the average concentration of oxygen molecules in the thickness portion from the specific surface to a depth of 200 μm is 0.8 × 10 ¹⁶ molecules / cc or more, high light emission intensity characteristics can be reliably obtained over a long period of time. .

The concentration of oxygen molecules in the synthetic quartz glass can be confirmed as follows.
That is, according to the following literature (1) to literature (3), oxygen molecules contained (impregnated) in silica glass are excited by light having a wavelength of 1272 nm or wavelength of 765 nm, and emit fluorescence having a wavelength of 1272 nm. By utilizing the fact that the fluorescence intensity increases in proportion to the oxygen molecule concentration (impregnated oxygen molecular weight), the peak intensity ratio between a standard sample with a clear oxygen molecule concentration and the sample whose oxygen molecule concentration should be measured. And can be quantified based on this. In addition, it is described that, in this quantification, since the fluorescence peak intensity is an integrated value in the sample thickness direction, it is necessary to consider the thickness ratio between the standard sample and the sample.
As a specific measurement system in such a technique, Documents (1) to (3) describe using an Nd: YAG laser as an excitation light source and measuring the fluorescence with a Raman spectroscopic analyzer. . Further, in order to obtain the oxygen molecule concentration of the sample surface layer, the following method is used. That is, the intensity of the oxygen fluorescence peak was measured before and after etching the 200 μm thick portion of the sample surface to obtain an oxygen fluorescence peak intensity difference, and this peak intensity difference reflected the oxygen molecular weight of the etched area. Thus, by calculating the quotient of the etching depth from the difference in peak intensity with respect to the etching depth, the concentration of oxygen molecules in the etched region is obtained.

Reference (1) Kajihara, J. et al. Appl. Phys, 98, 013527 (2005)
Reference (2) K.K. Kajihara, J. et al. Appl. Phys, 98, 013528 (2005)
Reference (3) K.K. Kajihara, J. et al. Appl. Phys, 98, 013529 (2005)

  Satisfying the above condition (4), that is, in the discharge vessel 21, the concentration of OH groups in the synthetic quartz glass that forms the surface layer on the specific surface side is greater than the concentration of OH groups in the synthetic quartz glass that forms the thickness center portion. In addition, since the effect of mitigating the growth of ultraviolet light strain due to the action of OH groups can be obtained by increasing the height, damage due to vacuum ultraviolet light on the synthetic quartz glass forming the discharge vessel 21, particularly ultraviolet light strain is accumulated. Since it can be suppressed and excellent optical characteristics can be obtained, the excimer lamp 20 can have high ultraviolet light resistance (ultraviolet light durability).

  As is clear from the experiment described later, the OH group concentration on the surface layer of both surfaces is equivalent to the thickness center portion, that is, the OH group concentration on the surface layer on the specific surface side is equivalent to the thickness center portion. In such a case, it is impossible to obtain high light emission intensity characteristics over a long period of time.

  Specifically, on the specific surface side of the discharge vessel 21, the concentration of OH groups in the synthetic quartz glass forming the surface layer is 70 wt.% In the thickness portion from the specific surface to a depth of 100 μm. It is preferable that it is ppm or more, especially 70-1300 wt. Preference is given to ppm. Further, the average concentration of the outermost surface consisting of the thickness portion up to a depth of 50 μm from the specific surface is 100 wt. It is preferably at least ppm.

Thus, the average concentration of OH groups in the thickness portion of 100 μm depth from the specific surface is 70 wt. By being at least ppm, it is possible to reliably obtain high light emission intensity characteristics over a long period of time.
Further, the concentration of OH groups in the thickness portion from the specific surface to a depth of 100 μm is 1300 wt. If it exceeds ppm, the discharge vessel 21 may be devitrified.

The concentration of OH groups in the synthetic quartz glass can be calculated based on the absorbance near the wavelength of 3670 cm ⁻¹ obtained by, for example, measuring an infrared absorption spectrum. As a specific method, (1) IR absorption measurement of the measurement object is performed, (2) Then, after measuring the measurement object portion (surface layer) in the measurement object, IR absorption measurement is further performed, and (3) Based on the difference between the measured values before and after the surface layer shaving process, the concentration of the shaved portion (surface layer) is calculated.

In the excimer lamp 20, it is preferable that the synthetic quartz glass forming the discharge vessel 21 has a fictive temperature Tf of 700 ° C. or higher and 930 ° C. or lower.
Here, the “virtual temperature Tf” is the equilibrium temperature in the case where the internal structure of the glass is represented by the temperature of the equilibrium state represented by the relationship between the temperature and the specific volume, and relates to the structure (density) of the glass. Indicates an indicator.

  By setting the fictive temperature Tf of the synthetic quartz glass to 700 ° C. or more and 930 ° C. or less, a molded body made of, for example, synthetic quartz glass is deformed during the process of manufacturing the excimer lamp 20 described later, and a discharge vessel having a desired shape is formed. Without adverse effects such as the inability to form a discharge, satisfying at least one of the conditions (3) and (4) together with the conditions (1) and (2), and having a desired ultraviolet light resistance A container can be obtained.

The fictive temperature Tf of the synthetic quartz glass can be obtained as follows.
That is, first, for example, a part of the same glass tube as that at the time of manufacturing the lamp is subjected to the same processing as the lamp, and samples each having a size of about 15 mm square are cut out from a plurality of different locations.
Then, the infrared transmission spectrum for each sample, for example, infrared spectrometer "Magna760" using (Nicoket Co.), by a transmission method, the range of wave number 2000～4000Cm ^-1, resolution 2 cm ^-1, wave number Measured with an interval of 0.0625 cm ⁻¹ and 32 times integration.
In the infrared transmission spectrum data thus obtained, the peak wave number in the absorption band of wave number 2260 cm ⁻¹ is obtained, and the average value of the peak wave number for each sample is defined as the peak wave number A [cm ⁻¹ ] in the excimer lamp. Is calculated from the following equation.

In the above formula 1, Tf is the fictive temperature [° C.], A is the peak wave number [cm ⁻¹ ], α and β are values obtained from the following formula 2, respectively, and F in formula 2 is the fluorine content (concentration) ) [Mol%].

  The excimer lamp 20 having such a configuration has, for example, a cylindrical inner tube constituting element tube that constitutes the inner tube 23 prepared in advance, and has an inner diameter larger than the outer diameter of the inner tube constituting element tube. By inserting the inner tube constituting element tube into the cylindrical outer tube constituting element tube constituting the tube 22 and arranging it coaxially, and heating from the outer side in the tube axis direction by, for example, a burner, The inner peripheral surface of the outer tube constituting element tube and the end surface of the end portion of the inner tube constituting element tube are welded to form a tubular discharge space H between the outer tube 22 and the inner tube 23. A discharge vessel 21 having a double tube structure is prepared. And it can manufacture by sealing the xenon gas which is discharge gas in the discharge space H in the produced discharge vessel 21, and arrange | positioning the outer side electrode 24 and the inner side electrode 25 in a predetermined position.

FIG. 3 and FIG. 4 are flowcharts of a method for producing an outer tube constituting element tube (hereinafter, also referred to as “discharge vessel element tube”) constituting the outer tube 22 of the discharge vessel 21 in such a manufacturing process. Will be described in detail.
Here, the method according to the flowchart of FIG. 3 is for producing a discharge vessel that satisfies at least the conditions (1) to (3), while the method according to the flowchart of FIG. ), A discharge vessel satisfying the conditions (2) and (4).
Note that the inner tube constituting element tube constituting the inner tube 23 can be formed by any of the methods according to the flowcharts of FIGS. 3 and 4.

  First, the method according to the flowchart of FIG. 3 will be described.

(Ingot production process)
First, an ingot (cylindrical base tube) made of synthetic quartz glass (raw material) having a fluorine content within the above range (condition (1)) is prepared.
In this ingot, the concentration of fluorine and the concentration of Si—F bonds in the synthetic quartz glass forming the ingot are uniform.

(Pipe forming process)
A pipe-shaped body is produced by forming an ingot into a pipe shape.
Even in this pipe-like body, the synthetic quartz glass forming the pipe-like body hardly has a gradient in the concentration of fluorine or Si—F bond in the thickness direction.
In the pipe forming process, the obtained pipe-shaped surface can be etched as necessary.
Even in a pipe-like body whose surface is etched, the concentration of fluorine and the concentration of Si-F bonds in the synthetic quartz glass forming the pipe-like body are uniform (see FIG. 11).

(Heat treatment process)
In this heat treatment process, the specific surface layer portion is formed on the surface layer on the outer surface side by subjecting the pipe-like body finally obtained in the pipe formation process to heat treatment, thereby producing a heat treatment body.

In this heat-treated body, as shown in FIG. 5, the concentration of Si—F bonds in the synthetic quartz glass forming the heat-treated body is substantially constant at the center of the thickness. Then, in the thickness direction, a concentration gradient that decreases toward the outer surface is generated.
The reason for this is that the pipe-like body finally obtained in the pipe-forming process is heat-treated, so that in the synthetic quartz glass forming the pipe-like body, the Si-F bonds are sequentially formed from the surface toward the center. This is because a part (of which the bond is weak) is cut, fluorine is released by this dissociation of the Si-F bond, and a Si-Si bond is formed.
Here, in FIG. 5, the horizontal axis indicates the thickness of the heat-treated body (the value “0” on the left end side indicates the outer surface, while the value “2000” on the right end side indicates the inner surface). The axis indicates the fluorine content (concentration), the concentration of each of the Si—F bond, oxygen atom, and Si—Si bond. Further, in the figure, the straight line (A) is the average fluorine concentration, the curve (B) is the Si-F bond concentration, the straight line (C) is the oxygen atom concentration, and the curve (D) is Si-Si. The concentration of binding is indicated.
The concentration of oxygen atoms can be confirmed by obtaining the concentration distribution of oxygen molecules in the thickness direction of the heat-treated body using, for example, SIMS (Secondary Ion Mass Spectrometry).

The heat treatment is performed, for example, by using a cylindrical heating furnace having a columnar hollow inside. Specifically, the pipe-shaped body is heated in the atmosphere by passing the inside of a cylindrical heating furnace.
The heat treatment conditions are, for example, a heating temperature of 1100 to 1300 ° C. and a treatment time of 3 to 30 minutes.
Here, since the dissociation of the Si-F bond proceeds depending on the heating temperature and the processing time, the specific surface layer portion can be set to the inner surface and the outer surface by controlling the heat processing state (adjusting the heat processing conditions). It can also be formed on the surface layer of one of the surfaces, or can be formed on the surface layer of both surfaces.
In this example, the surface layer on the outer surface side of the heat treatment body has a significantly reduced concentration of Si-F bonds to form a specific surface layer portion, and the surface layer on the inner surface side of the heat treatment body (from the specific inner surface) Even in a region (depth up to a depth of less than 50 μm), the level is small, but the concentration of Si—F bonds is reduced.

(Oxygen doping process)
In this oxygen doping treatment process, oxygen molecules are introduced by performing oxygen doping treatment on the heat treatment body obtained in the heat treatment process, thereby producing an oxygen doping treatment body.

In this oxygen doped body, as shown in FIG. 6, the concentration of oxygen molecules in the synthetic quartz glass forming the oxygen doped body is increased in the surface layer (particularly the surface layer on the outer surface side), At the same time, the Si—Si bond concentration is lower than the Si—Si bond concentration in the synthetic quartz glass forming the heat-treated body.
In FIG. 6, the concentration of oxygen atoms is increased on the outer surface side and the surface layer on the inner surface side of the oxygen-doped body, but this also decreases the concentration of Si—Si bonds. It has been shown.
Here, in FIG. 6, the horizontal axis indicates the thickness of the oxygen-doped body (the value “0” on the left end side indicates the outer surface, while the value “2000” on the right end side indicates the inner surface). The vertical axis represents the fluorine content (concentration), the concentration of each of the Si—F bonds, oxygen molecules, oxygen atoms and Si—Si bonds. In addition, in the figure, the straight line (A) indicates the average concentration of fluorine, the curve (B) indicates the concentration of Si-F bonds, the curve (C) indicates the concentration of oxygen atoms, and the curve (D) indicates Si. The concentration of -Si bond, the curve (e) indicates the concentration of oxygen molecules, and the straight line (f) indicates the concentration of oxygen atoms before the oxygen doping treatment.

  The reason why the concentration of Si-Si bonds formed in the heat treatment process in the oxygen-doped body is reduced is that, according to the oxygen-doping treatment for the heat-treated body, first, the Si-Si bonds existing in the surface layer of the heat-treated body On the other hand, O (oxygen atom) acts to form a Si—O—Si bond, and thus the Si—Si bond is formed from the Si—Si bond, thereby reducing the concentration of the Si—Si bond. This is because the oxygen molecules themselves are introduced in that form.

The oxygen doping treatment is performed by heating the heat treatment body in an oxygen atmosphere.
The oxygen doping treatment conditions are, for example, an oxygen pressure (oxygen concentration) of 0.3 to 1.5 atm, a heating temperature of 600 to 1000 ° C., a treatment time of 1 to 300 hours, and particularly preferably a heating temperature of 750 ° C.

  In this way, the oxygen-doped body obtained through the ingot production process, pipe forming process, heat treatment process and oxygen doping process can be used as it is as a raw tube for a discharge vessel. An OH group doping process described later can also be performed. Here, a discharge vessel satisfying all of the conditions (1) to (4) can be obtained by going through the ingot preparation process, the pipe forming process, the heat treatment process, the oxygen doping process and the OH group doping process in this order. Can do.

Next, a method according to the flowchart of FIG. 4 will be described.
This method is similar to the method shown in FIG. 3 in that an ingot manufacturing process, a pipe forming process, and a heat treatment process are performed in this order to obtain a heat treatment body, and this heat treatment body is doped with an OH group instead of an oxygen doping process. Processing is performed.

(OH group doping process)
In this OH group doping treatment process, OH groups are introduced by subjecting the heat treatment body obtained in the heat treatment process to OH group doping treatment, thereby producing an OH group doping treatment body.

In this OH group-doped treated body, as shown in FIG. 7, the concentration of OH groups in the synthetic quartz glass forming the OH group-doped treated body is increased on the surface layer (particularly the surface layer on the outer surface side). At the same time, the Si—Si bond concentration is smaller than the Si—Si bond concentration in the synthetic quartz glass forming the heat-treated body.
Here, in FIG. 7, the horizontal axis represents the thickness of the OH group-doped treated body (the value “0” on the left end side indicates the outer surface, while the value “2000” on the right end side indicates the inner surface). The vertical axis represents the fluorine content (concentration), the Si-F bond, the Si-Si bond, and the OH group concentration. In the figure, the straight line (a) shows the average fluorine concentration, the curve (b) shows the Si-F bond concentration, the curve (d) shows the Si-Si bond concentration, and the curve (g) shows the curve. , OH group concentration.

The reason why the concentration of Si—Si bonds formed in the heat treatment process in the OH group doped body was reduced was introduced in the state of water molecules (H ₂ O) according to the OH group dope treatment on the heat treated body. Since the OH group reacts with the Si—Si bond existing on the surface layer of the heat-treated body, thereby forming a Si—OH dangling bond (free end), the Si—Si bond is thus removed from the Si—Si bond. This is because the concentration of Si—Si bonds is reduced by the formation of —OH dangling bonds.

The OH group doping treatment is performed by heating the heat treatment body while generating water vapor in an inert gas atmosphere such as nitrogen gas, argon gas, or helium gas.
The OH group dope treatment conditions are, for example, a water vapor concentration of 10 to 80%, a heating temperature of 600 to 1000 ° C., a treatment time of 0.2 to 30 hours, and particularly preferably a heating temperature of 750 ° C.

In this way, the OH group doped body obtained through the ingot production process, pipe forming process, heat treatment process and OH group dope process can be used as it is as a raw tube for a discharge vessel. The oxygen doping process described above can also be performed.
Here, a discharge vessel satisfying all of the conditions (1) to (4) can be obtained also through the ingot production process, pipe forming process, heat treatment process, OH group doping process and oxygen doping process in this order. Can do.
FIG. 8 shows a discharge vessel (outer tube) made of synthetic quartz glass having a thickness of 2 mm, manufactured in this order through an ingot production process, pipe forming process, heat treatment process, OH group doping process and oxygen doping process. The composition of the synthetic quartz glass to be formed is shown. In FIG. 8, the concentration of OH groups is smaller in the vicinity of the surface on the outer surface side of the discharge vessel (outer tube) than the OH group-doped treated body (see FIG. 7). This is because the oxygen doping treatment was performed after the doping treatment, so that the OH group of the Si—OH dangling bond was cut in the vicinity of the surface.
Here, in FIG. 8, the horizontal axis indicates the thickness of the discharge vessel (outer tube) (the value “0” on the left end side indicates the outer surface, while the value “2000” on the right end side indicates the inner surface). The vertical axis represents the fluorine content (concentration), the concentration of each of the Si—F bond, oxygen molecule, oxygen atom, Si—Si bond and OH group. In addition, in the figure, the straight line (A) indicates the average concentration of fluorine, the curve (B) indicates the concentration of Si-F bonds, the curve (C) indicates the concentration of oxygen atoms, and the curve (D) indicates Si. -Si bond concentration, curve (e) indicates the concentration of oxygen molecules, straight line (f) indicates the concentration of oxygen atoms before the oxygen doping treatment, and curve (g) indicates the concentration of OH groups.

According to any of the method according to FIG. 3 and the method according to FIG. 4 as described above, the oxygen doping treatment and the OH group doping treatment are specified on the surface layer on at least one surface side of the pipe-shaped body in the heat treatment process. By applying after the formation of the surface layer portion, that is, the portion having a low concentration of Si—F bonds, the surface layer on the surface side has a low concentration of Si—Si bonds formed in the heat treatment process, and in addition, oxygen molecules With the OH group and the OH group, a desired state in which fluorine in a free state is present can be obtained.
That is, when oxygen doping treatment or OH group doping treatment is performed on the pipe-like body finally obtained in the pipe forming process without performing the heat treatment process (for example, see FIG. 12), oxygen molecules and Even if an OH group is introduced, since there is no fluorine in a free state, Si—Si bonds are gradually generated from Si—F bonds, and as a result, the radiation intensity of vacuum ultraviolet light is maintained. The rate will gradually decline.

In the excimer lamp 20 having such a configuration, for example, a high-frequency voltage controlled to an appropriate magnitude is applied between the outer electrode 24 and the inner electrode 25 by the power supply device 26, so that the inside of the discharge space H The excimer discharge is generated in this, and excimer discharge generates excimer molecules derived from xenon gas (discharge gas), and light including vacuum ultraviolet light having a wavelength of 190 nm or less is emitted inside the discharge vessel 11.
In this excimer lamp 20, light in the vicinity of the ultraviolet absorption edge of synthetic quartz glass having a wavelength of 145 to 160 nm is also radiated as xenon excimer radiation inside the discharge vessel 21. It will be absorbed by the synthetic quartz glass forming.

  In this way, the light near the ultraviolet absorption edge is absorbed by the synthetic quartz glass, so that in a conventional discharge lamp having a discharge vessel made of synthetic quartz glass simply containing fluorine, The Si—F bond existing in the vicinity of the surface is dissociated and fluorine is liberated. Along with this, a Si—Si bond that causes a decrease in light emission intensity of vacuum ultraviolet light and ultraviolet distortion is formed. The concentration of will increase.

Thus, in the excimer lamp 20, the fluorine content of the synthetic quartz glass forming the discharge vessel 21 is optimized as the discharge vessel 21, and either the inner surface or the outer surface, or both surfaces are used. In the surface layer (specifically, the surface layer on the outer surface side of the outer tube 22), the concentration of oxygen molecules and the concentration of OH groups, together with the concentration of Si-F bonds in the synthetic quartz glass, from the relationship with the thickness center portion. Since at least one of the concentrations is made of a specific material having a specific range, fluorine is contained in two existing forms in the synthetic quartz glass forming the surface layer of the discharge vessel. Specifically, the amount of fluorine present by forming Si—F bonds that can be a source of generation of Si—Si bonds by the action of light (light near the ultraviolet absorption edge) is small. As a result, there is fluorine (fluorine molecule) in a free state, and in addition to this, at least one of oxygen molecules and OH groups is present. The formation of Si—Si bonds, which is a cause of the decrease in strength and ultraviolet distortion, is suppressed, and as a result, the increase in the concentration of Si—Si bonds in the synthetic quartz glass is suppressed.
Accordingly, since the excellent characteristics (high ultraviolet transmittance) obtained by including fluorine itself in the synthetic quartz glass are maintained for a long period of time, the synthetic quartz glass forming the discharge vessel 21 absorbs ultraviolet rays. By absorbing the light near the edge, the presence form of fluorine contained in the synthetic quartz glass changes with time, and it is possible to suppress the deterioration of the light emission intensity maintenance characteristic due to this.

  That is, when the conditions (1) to (3) are satisfied, light can act on the synthetic quartz glass forming the surface layer on at least one side of the discharge vessel 21 to become a generation source of Si—Si bonds. The amount of fluorine present by forming the Si-F bond is reduced, and as a result, free fluorine (fluorine molecules) is present, and in addition, oxygen molecules are present. Even when dissociation occurs in the Si-F bond by the action of Si, a new Si-F bond is formed based on the Si-F bond cleaved by the fluorine reservoir function in the released state, and oxygen is released. Since the Si—O—Si bond is formed based on the Si—F bond cleaved by the action of the molecule, the formation of the Si—Si bond is inhibited.

  Further, when the condition (1), the condition (2) and the condition (4) are satisfied, light acts on the synthetic quartz glass forming the surface layer on at least one side of the discharge vessel so that the Si—Si bond is formed. The amount of fluorine present is reduced by forming a Si-F bond that can be a generation source, and in accordance with this, free fluorine (fluorine molecules) is present, and in addition, Si-OH dangling bonds Si-Si bonds that exist together with fluorine in a free state as the concentration of Si-F bonds is reduced because of the presence of OH groups that will be present by forming However, the Si—Si bond concentration itself is reduced in the manufacturing process, and the Si—F bond is dissociated by the action of light. A new Si-F bond is formed on the basis of the Si-F bond cleaved by the fluorine reservoir function in the released state, and the Si-Si bond is formed due to the growth relaxation effect of the ultraviolet light strain caused by the OH group. Is inhibited.

  Further, since the discharge vessel 21 contains at least one of oxygen molecules and OH groups at a specific concentration in the surface layer on at least one side, the action of oxygen molecules and / or the action of OH groups can be ensured. Therefore, it is possible to reliably obtain high ultraviolet light resistance, and to obtain a further excellent ultraviolet light resistance for the discharge lamp, that is, to obtain a high vacuum ultraviolet light radiation intensity, High light emission intensity characteristics can be maintained over a long period of time.

<Light emitting device>
In the light emitting device of the present invention, a discharge lamp that radiates light including ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel is used as a light source. Synthetic quartz glass for radiating light from the discharge lamp It has a configuration in which a light emission window made of metal is provided.
In the light emitting device of the present invention, the fluorine content (concentration) of the synthetic quartz glass forming the entire light emitting window or a part of the light emitting window such as a member of the light emitting portion as the light emitting window. ) And at least one of the oxygen molecule concentration and the OH group concentration in the synthetic quartz glass together with the concentration of the Si-F bond in the surface layer on at least one side of the synthetic quartz glass. One of the specific materials having a specific range is used, and thereby, the transmission characteristics on the short wavelength side in vacuum ultraviolet light are improved.

That is, in the light emitting device of the present invention, the light emitting window made of synthetic quartz glass satisfies the above conditions (1) and (2) as well as the condition (3) or the same as the discharge lamp of the present invention. The condition (4) is satisfied.
In addition, the light emitting device of the present invention is not limited as long as the light emitting window satisfies at least one of the conditions (3) and (4) together with the conditions (1) and (2). It is preferable that all of these conditions (1) to (4) are satisfied.

  In the above-described light emitting device of the present invention, since a discharge lamp that emits light including vacuum ultraviolet light is used as a light source, a light emitting window arranged in the vicinity of the discharge lamp has a discharge. The light emitted from the lamp is irradiated with light in the vicinity of the ultraviolet absorption edge of the synthetic quartz glass, and the heat from the discharge vessel of the discharge lamp is received, but at least a part of the light emission window is used as the light emission window. The content of fluorine in the synthetic quartz glass forming the surface of the synthetic quartz glass is optimized, and at least one of the surface layers has a concentration of Si-F bonds in the synthetic quartz glass due to the relationship with the thickness center. Since a specific material having a specific range in which at least one of the concentration and the concentration of OH groups is in a specific range is used, the same effect as the above-described discharge lamp of the present invention can be obtained. As a result, high radiation intensity of the vacuum ultraviolet light, moreover, it is possible to maintain a high light emission intensity characteristics over a long period of time, therefore, it is possible to obtain an excellent 耐紫 external light characteristic.

  Hereinafter, experimental examples performed for confirming the effects of the present invention will be described.

<Experimental example 1>
This Experimental Example 1 was conducted in order to examine the fluorine content in the synthetic quartz glass.

[Production of excimer lamp]
Eight discharge containers are formed using eight types of synthetic quartz glass (raw materials) each containing fluorine in different contents (concentrations) according to Table 1 below, and the inner and outer electrodes are arranged at predetermined positions. At the same time, xenon gas was filled in the discharge space to produce eight excimer lamps ("lamp 11" to "lamp 18") having the configuration shown in FIG.
The obtained lamps 11 to 18 were produced by heat-treating the discharge vessel base tube constituting the outer tube and the inner tube of the discharge vessel for 5 hours in the atmosphere at a heating temperature of 800 ° C. It has been done. Specifically, the outer tube has an outer diameter of 40 mm, the outer tube has a thickness of 2 mm, the inner tube has an outer diameter of 20 mm, the inner tube has a wall thickness of 1 mm, and a light emission length of 400 mm. The discharge vessel has a configuration in which xenon gas is sealed in an amount of 66 kPa.

For each of the lamps 11 to 18 thus obtained, a lamp life test was performed, and the radiation intensity of vacuum ultraviolet light having a wavelength of 190 nm or less was measured. The results are shown in Table 1 below.
In the life test, the lamp was continuously lit under a lighting condition where the lamp power was 400 W, and the time until the discharge vessel was damaged was defined as the life time.
The radiation intensity was measured with a light meter at a position 30 mm away from the lamp.

  In addition, after the same processing as that for producing a lamp was performed on a part of the same glass tube (raw material) that constitutes each lamp, three samples each having a size of about 15 mm square were cut out, The fictive temperature Tf at the thickness center was measured by the above method. The results are shown in Table 1 below.

As is clear from the results of Experimental Example 1, fluorine was 7000 wt. ppm to 30000 wt. Each of the lamps 13 to 17 satisfying the condition (1) including a discharge vessel made of synthetic quartz glass contained at a ratio of ppm or less can emit vacuum ultraviolet light with high radiation intensity, It was confirmed to have a long lamp life.
Here, in such a xenon excimer lamp having a double tube structure, for example, a lamp life of 3000 hours or more is required, and the lamps 13 to 17 may sufficiently satisfy such a requirement. confirmed.
On the other hand, the fluorine content in the synthetic quartz glass is 7000 wt. The lamp 11 and the lamp 12 that are less than ppm and do not satisfy the condition (1) have a lower emission intensity of vacuum ultraviolet light than the lamps 13 to 17, and a lamp life that satisfies the above requirements cannot be obtained. confirmed. The synthetic quartz glass has a fluorine content of 30000 wt. It was confirmed that the lamp 18 which is higher than ppm and does not satisfy the condition (1) also has a lower radiant intensity of vacuum ultraviolet light than the lamps 13 to 17, and a lamp life satisfying the above requirements cannot be obtained. .
Therefore, in the discharge lamp and the light emitting device, the fluorine content in the synthetic quartz glass forming the discharge vessel and the light emitting window is set to 7000 wt. ppm to 30000 wt. It was confirmed that by setting it to ppm or less, vacuum ultraviolet light can be emitted with high radiation intensity and a long service life can be obtained.

<Experimental example 2>
This Experimental Example 2 was conducted in order to examine the concentration of oxygen molecules in the synthetic quartz glass.

[Production of excimer lamp]
The fluorine content (concentration) is 7000 wt. Forming five discharge vessels using synthetic quartz glass (raw material) of ppm, disposing the inner and outer electrodes at predetermined positions and filling the discharge space with xenon gas, the configuration shown in FIG. Four excimer lamps ("Lamp 21" to "Lamp 24") having the above-described characteristics were manufactured.

In the obtained lamps 21 to 24, each of the outer tube constituting element tubes constituting the outer tube of the discharge vessel forms an ingot made of synthetic quartz glass as a raw material, and the ingot is molded to form a pipe shape. After the heat treatment was performed by inserting the pipe-shaped body into a cylindrical heating furnace and passing it for 5 to 10 minutes while maintaining the temperature in the heating furnace at 1150 ° C., Table 2 It was produced by performing oxygen doping treatment under the oxygen doping treatment conditions shown in FIG.
These excimer lamps have the same specific configuration as the excimer lamp manufactured in Experimental Example 1. The lamp 13 in Experimental Example 2 is the same as that manufactured in Experimental Example 1.

For each of the lamp 13 and the lamps 21 to 24 thus obtained, the initial radiation intensity of vacuum ultraviolet light having a wavelength of 190 nm or less and the radiation intensity after continuous lighting for 3000 hours were measured. Moreover, the radiation intensity maintenance factor was calculated based on the obtained initial radiation intensity and the radiation intensity after 3000 hours of continuous lighting. The results are shown in Table 2 below.
The radiation intensity was measured with a light meter at a position 30 mm away from the lamp.
Moreover, the average concentration of oxygen molecules in the synthetic quartz glass forming each of the thickness part and the thickness center part from the surface of the discharge vessel to a depth of 200 μm was confirmed by the above method. The results are shown in Table 2 below.
Further, the fictive temperature Tf at the thickness center was measured for each excimer lamp in the same manner as in Experimental Example 1. The results are shown in Table 2 below.
In this experimental example, the Si-F bond concentration was significantly decreased by heat treatment (see the results relating to the lamps 21 to 24). Measurement on the outer surface side (outer surface side of the outer tube) Only the values are shown as representative examples.

As is clear from the results of Experimental Example 2, fluorine was 7000 wt. In an excimer lamp having a discharge vessel made of synthetic quartz glass contained in ppm, a synthesis for forming a surface layer (specifically, a surface layer on the outer surface side of the outer tube) on at least one surface of a part of the discharge vessel The concentration of Si—F bonds and the concentration of oxygen molecules in the quartz glass are higher than the respective concentrations related to the thickness center portion, satisfy the conditions (1) to (2), and have a depth of 200 μm from the at least one surface. The average concentration of oxygen molecules in the synthetic quartz glass forming the thickness portion up to 0.8 × 10 ¹⁶ pieces / cc or more can radiate vacuum ultraviolet light with high radiation intensity. At the same time, it was confirmed to have a high radiation intensity maintenance rate of vacuum ultraviolet light.
On the other hand, the synthetic quartz glass contains fluorine in an appropriate range, and Si-F related to the surface layer (specifically, the surface layer on the outer surface side of the outer tube) on at least one surface of a part of the discharge vessel. Although the concentration of the bond is appropriate, the concentration of oxygen molecules in the surface layer and the thickness center is equal and does not satisfy the condition (3), and the average concentration of oxygen molecules in a specific thickness portion is It was confirmed that the lamp 13 which is less than 0.8 × 10 ¹⁶ pieces / cc does not have a sufficient vacuum ultraviolet light radiation intensity maintenance rate.
In addition, although it was confirmed that the lamp 21 has a sufficiently high vacuum ultraviolet light radiation intensity maintenance rate, since the fictive temperature is as low as 660 ° C., 200 hours or more are required to manufacture the lamp 21. It was necessary to perform oxygen doping treatment for a long time.
Therefore, in the discharge lamp and the light emitting device, the desired effect can be ensured by setting the average concentration of oxygen molecules in the synthetic quartz glass forming the discharge vessel and the light emitting window to 0.8 × 10 ¹⁶ atoms / cc or more. It was confirmed that
Further, it was confirmed from the industrial viewpoint that the fictive temperature is preferably 700 ° C. or higher and 930 ° C. or lower.

<Experimental example 3>
This Experimental Example 3 was performed in order to examine the relationship between the concentration of Si—F bonds and the concentration of oxygen molecules in the synthetic quartz glass.

[Production of excimer lamp]
The fluorine content (concentration) is 10500 wt. ppm or 8000 wt. Four discharge vessels are formed using synthetic quartz glass (raw material) with a fictive temperature measured by the above-described method and shown in Table 3, and the inner and outer electrodes are arranged at predetermined positions. In addition, by filling the discharge space with xenon gas, four excimer lamps (“lamp 31” to “lamp 34”) having the configuration shown in FIG. 1 were produced.

In the lamp 31 thus obtained, the outer tube constituting element tube constituting the outer tube of the discharge vessel does not form a portion having a low concentration of Si-F bonds on the surface layers of both surfaces, and thus oxygen doping treatment (oxygen treatment) Synthetic quartz glass which is produced by performing dope treatment conditions: oxygen pressure of 1 atm, heating temperature of 750 ° C., treatment time of 4 hours, and as a result, forms both the surface layer and the thickness center of both surfaces of the discharge vessel The concentration of the Si-F bond in it is the same.
In addition, each of the lamps 32 to 34 is subjected to an oxygen doping treatment (oxygen doping treatment condition: oxygen pressure of 1 atm, after the outer tube constituting element tube constituting the outer tube of the discharge vessel is heat-treated under appropriate conditions. (Heating temperature 800 ° C., treatment time 5 hours).
These excimer lamps have the same specific configuration as the excimer lamp manufactured in Experimental Example 1. The lamp 15 in Experimental Example 3 is the same as that manufactured in Experimental Example 1, and the concentration of Si—F bonds and the concentration of oxygen molecules in the synthetic quartz glass that forms the surface layers on both surfaces of the discharge vessel. Is equivalent to the center of thickness.

For each of the lamp 15 and the lamps 31 to 34 thus obtained, the initial radiant intensity and the radiant intensity after 3000 hours of continuous lighting were measured in the same manner as in Experimental Example 2, and the radiant intensity maintenance rate was calculated. . The results are shown in Table 3 below.
Further, in the same manner as in Experimental Example 2, the average concentration of oxygen molecules in the synthetic quartz glass forming each of the thickness portion from the surface of the discharge vessel to a depth of 200 μm and the thickness center portion was confirmed. The results are shown in Table 3 below.
Further, the fictive temperature Tf at the thickness center was measured for each lamp in the same manner as in Experimental Example 1. The results are shown in Table 3 below.
In this experimental example, the Si-F bond concentration was significantly reduced by heat treatment (see the results relating to the lamps 31 to 34). Measurement on the outer surface side (outer surface side of the outer tube) Only the values are shown as representative examples.

As is clear from the results of Experimental Example 3, fluorine was 8000 wt. ppm or 10500 wt. In an excimer lamp having a discharge vessel made of synthetic quartz glass contained in ppm, a synthesis for forming a surface layer (specifically, a surface layer on the outer surface side of the outer tube) on at least one surface of a part of the discharge vessel The concentration of Si—F bonds and the concentration of oxygen molecules in the quartz glass are higher than each concentration related to the thickness center portion, satisfy the conditions (1) to (2), and have a depth of 200 μm from the surface of the discharge vessel. The average concentration of oxygen molecules in the synthetic quartz glass forming the thickness part up to 0.8 × 10 ¹⁶ pieces / cc or more can radiate vacuum ultraviolet light with high radiation intensity. At the same time, it was confirmed to have a high radiation intensity maintenance rate of vacuum ultraviolet light.
On the other hand, despite the fact that synthetic quartz glass contains fluorine in an appropriate range, the concentration of Si—F bonds and oxygen in each of the surface layer and the center of the thickness of both surfaces of the discharge vessel A lamp 15 in which the concentration of molecules is equal, the conditions (2) and (3) are not satisfied, and the average concentration of oxygen molecules in a specific thickness portion is less than 0.8 × 10 ¹⁶ molecules / cc. Thus, it was confirmed that it does not have a sufficient radiation intensity maintenance rate of vacuum ultraviolet light.
In addition, the synthetic quartz glass contains fluorine in an appropriate range, and the concentration of oxygen molecules on the surface layer (specifically, the surface layer on the outer surface side of the outer tube) on at least one surface of a part of the discharge vessel is appropriate. Nevertheless, the lamp 31 that does not satisfy the condition (2) in which the concentration of the Si—F bond in each of the surface layer and the thickness center is equal has a sufficient radiation intensity maintenance rate of vacuum ultraviolet light. It was confirmed not to.
Therefore, in the discharge lamp and the light emission device, in the discharge lamp and the light emission device, fluorine in a state of being released together with oxygen molecules in the synthetic quartz glass forming the surface layer of at least one surface of the discharge vessel and the light emission window. It was confirmed that the desired effect was obtained by the presence of.
That is, on both surfaces, there is no free fluorine in the synthetic quartz glass forming the surface layer, and only the presence of oxygen molecules can sufficiently suppress the decrease in light emission intensity maintenance characteristics. Can not.
Further, it was confirmed that when oxygen doping treatment was performed without passing through the heat treatment process, even if oxygen molecules could be introduced, free fluorine could not be present.

<Experimental example 4>
This Experimental Example 4 was performed in order to examine the concentration of OH groups in the synthetic quartz glass.

[Production of excimer lamp]
The fluorine content (concentration) is 10500 wt. Nine discharge vessels are formed using synthetic quartz glass (raw material) of ppm, the inner electrode and the outer electrode are disposed at predetermined positions, and the xenon gas is filled in the discharge space, whereby the configuration shown in FIG. Nine excimer lamps (“LAMP 41” to “LAMP 48”) were produced.

In the lamp 41 and the lamp 44 obtained, the outer tube constituting element tube constituting the outer tube of the discharge vessel forms an ingot made of synthetic quartz glass as a raw material, and the ingot is molded to form a pipe shape. After obtaining a body and heat-treating this pipe-shaped body under an appropriate condition using a cylindrical heating furnace, conditions set based on a virtual temperature obtained in advance using an electric furnace (set heating temperature and heating time) After adjusting the fictive temperature Tf, the heat treatment was performed in a dry atmosphere at a heating temperature of 800 ° C. for 5 hours, and then OH group doping treatment was performed under the OH group doping treatment conditions shown in Table 4. Is.
In addition, the lamp 42 has a pipe-shaped body obtained by forming an ingot from the raw material of the outer tube constituting element tube constituting the outer tube of the discharge vessel in the same manner as the manufacturing method of the lamp 41 and the lamp 44. After adjusting the fictive temperature Tf by heat treatment, the heat treatment is performed for 200 hours at a heating temperature of 650 ° C. in a dry atmosphere, and then OH group doping treatment is performed according to the OH group doping treatment conditions shown in Table 4. It was produced by doing.
Further, the lamp 43 has a pipe-shaped body obtained by forming an ingot from the raw material of the outer tube constituting element tube constituting the outer tube of the discharge vessel in the same manner as the manufacturing method of the lamp 41 and the lamp 44. After adjusting the fictive temperature Tf by heat treatment, the heat treatment was performed for 5 hours in a dry atmosphere at a heating temperature of 780 ° C., and then the OH group doping treatment was performed according to the OH group doping treatment conditions shown in Table 4. It was produced by doing.
In addition, each of the lamps 45 to 48 is a pipe-shaped body in which the outer tube constituting element tube constituting the outer tube of the discharge vessel forms an ingot from the raw material in the same manner as the manufacturing method of the lamp 41 and the lamp 44. After the pipe-shaped body was heat-treated, it was produced by OH group doping treatment under the OH group doping treatment conditions shown in Table 4.
These excimer lamps have the same specific configuration as the excimer lamp manufactured in Experimental Example 1. In addition, the lamp 15 in Experimental Example 4 is the same as that manufactured in Experimental Example 1.

For each of the lamp 15 and the lamps 41 to 48 thus obtained, the initial radiant intensity and the radiant intensity after 3000 hours of continuous lighting were measured in the same manner as in Experimental Example 2, and the radiant intensity maintenance rate was calculated. . The results are shown in Table 4 below.
In addition, the average concentration of OH groups in the synthetic quartz glass forming each of the thickness portion from the surface of the discharge vessel to a depth of 100 μm and the central thickness portion was confirmed by FTIR method (Fourier transform infrared spectroscopy). . The results are shown in Table 4 below.
Further, the fictive temperature Tf at the thickness center was measured for each lamp in the same manner as in Experimental Example 1. The results are shown in Table 4 below.
In this experimental example, the Si—F bond concentration was significantly reduced by heat treatment (see the results relating to 41 to 48). The measured value on the outer surface side (the outer surface side of the outer tube). Only a representative example is shown.

  In Table 4, “inert gas” is specifically nitrogen gas.

As is clear from the results of Experimental Example 4, fluorine was 10500 wt. In an excimer lamp having a discharge vessel made of synthetic quartz glass contained in ppm, a synthesis for forming a surface layer (specifically, a surface layer on the outer surface side of the outer tube) on at least one surface of a part of the discharge vessel The thickness of the Si-F bond concentration and the oxygen molecule concentration in the quartz glass are higher than the respective concentrations related to the thickness center, satisfy the conditions (1) and (3), and have a depth from the surface to a depth of 100 μm. The average concentration of OH groups in the synthetic quartz glass forming the portion is 70 wt. It was confirmed that the lamps 41 to 48 which are equal to or higher than ppm can emit vacuum ultraviolet light with high radiation intensity and have a high vacuum ultraviolet light radiation intensity maintenance rate.
On the other hand, despite the fact that the synthetic quartz glass contains fluorine in an appropriate range, the concentration of Si—F bonds and OH in each of the surface layer and the central thickness portion of both surfaces of the discharge vessel Both groups have the same concentration, do not satisfy the conditions (2) and (4), and the average concentration of OH groups in a specific thickness portion is 70 wt. It was confirmed that the lamp 15 of less than ppm does not have a sufficient vacuum ultraviolet light radiation intensity maintenance rate.
Therefore, in the discharge lamp and the light emission device, the average concentration of OH groups in the synthetic quartz glass forming the discharge vessel and the light emission window is 70 wt. It was confirmed that the desired effect can be surely obtained by setting the content to ppm or more.

<Experimental example 5>
In Experimental Example 5, an ingot preparation process, a pipe forming process, and a heat treatment process are performed in this order, and then oxygen doping treatment and OH group doping treatment are performed. That is, the ingot preparation process, pipe forming process, heat treatment process, oxygen doping treatment process, and This was carried out in order to confirm the material and characteristics of the discharge vessel obtained through the entire OH group doping process.

[Production of excimer lamp]
The fluorine content (concentration) is 10500 wt. By forming seven discharge vessels using synthetic quartz glass (raw material) of ppm, arranging the inner and outer electrodes at predetermined positions and filling the discharge space with xenon gas, the configuration shown in FIG. The seven excimer lamps ("Lamp 51" to "Lamp 57") having the above-mentioned were manufactured.

In the obtained lamps 51 to 55, the outer tube constituting element tube constituting the outer tube of the discharge vessel forms an ingot made of synthetic quartz glass as a raw material, and the ingot is formed into a pipe shape. After obtaining the body and heat-treating the pipe-like body under a suitable condition using a cylindrical heating furnace, the heat-treatment is performed in the atmosphere at a heating temperature of 750 ° C. for 5 hours, and then in an oxygen atmosphere. By performing heat treatment under appropriate conditions (heating temperature 600 to 1000 ° C., treatment time 1 to 30 hours) in an environment where water vapor is generated, thereby performing OH group doping treatment and oxygen molecule doping treatment simultaneously. It was produced.
In the lamp 56, the outer tube constituting element tube constituting the outer tube of the discharge vessel forms an ingot made of synthetic quartz glass as a raw material, and a pipe-like body is obtained by molding the ingot. The cylindrical body is heat-treated under a suitable condition using a cylindrical heating furnace, and then heat-treated in the atmosphere at a heating temperature of 750 ° C. for 5 hours. Thereafter, first, oxygen molecule doping treatment (oxygen doping treatment) Conditions: oxygen pressure 1 atm, heating temperature 750 ° C., treatment time 25 hours), then OH group dope treatment (OH group dope treatment condition: inert gas (nitrogen gas) pressure 1 atm, water vapor concentration 10%, heating temperature 750 ° C., treatment time 2 hours).
In addition, the lamp 57 has a pipe-shaped body obtained by forming an ingot made of synthetic quartz glass, which is a raw material, of the outer tube constituting element tube constituting the outer tube of the discharge vessel. After heat-treating the body with a cylindrical heating furnace under appropriate conditions, heat treatment is performed in the atmosphere at a heating temperature of 750 ° C. for 5 hours, and then, first, OH group doping treatment (OH group doping treatment) Conditions: Inert gas (nitrogen gas) pressure 1 atmosphere, water vapor concentration 10%, heating temperature 750 ° C., treatment time 2.5 hours), then oxygen molecule doping treatment (oxygen doping treatment condition: oxygen pressure 1 atmosphere, heating) The temperature was 750 ° C. and the treatment time was 25 hours).
These excimer lamps have the same specific configuration as the excimer lamp manufactured in Experimental Example 1. Also in the manufacturing process of the chair lamp, the heat treatment using the cylindrical heating furnace was performed under the conditions of the heating temperature in the range of 1100 to 1300 ° C. and the treatment time in the range of 3 to 30 minutes. .

For each of the lamps 51 to 57 thus obtained, the initial radiant intensity and the radiant intensity after 3000 hours of continuous lighting were measured in the same manner as in Experimental Example 2, and the radiant intensity maintenance rate was calculated. The results are shown in Table 5 below.
Further, in the same manner as in Experimental Example 2, the average concentration of oxygen molecules in the synthetic quartz glass forming each of the thickness portion from the surface of the discharge vessel to a depth of 200 μm and the central thickness portion was confirmed, and Experimental Example 4 In the same manner as above, the average concentration of OH groups in the synthetic quartz glass forming the thickness portion from the surface of the discharge vessel to a depth of 100 μm and the thickness center portion was confirmed. The results are shown in Table 5 below.
Further, the fictive temperature Tf at the thickness center was measured for each lamp in the same manner as in Experimental Example 1. The results are shown in Table 5 below.
In this experimental example, only the measured values on the outer surface side (outer surface side of the outer tube) where the decrease in the Si-F bond concentration was remarkable due to the heat treatment are shown as representative examples.

As is clear from the results of Experimental Example 5, the lamps 51 to 57 that satisfy all of the conditions (1) to (4) can emit vacuum ultraviolet light with high radiation intensity and high vacuum ultraviolet light. It was confirmed to have a radiation intensity maintenance factor of.
Further, in the manufacturing process of the discharge vessel, after the ingot preparation process, the pipe forming process, and the heat treatment process are performed in this order, and then both the oxygen doping process and the OH group doping process are performed, the conditions (1) to (4) It was confirmed that a discharge vessel satisfying all of the conditions can be obtained.
In addition, after the ingot preparation process, pipe forming process and heat treatment process in this order, even if the oxygen doping treatment and the OH group doping treatment are performed at the same time, or if any treatment is performed first In addition, it was confirmed that a discharge vessel satisfying all the conditions (1) to (4) was obtained.

As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment, A various change can be added.
For example, the discharge lamp of the present invention is not limited to a xenon excimer lamp, and may be any discharge lamp that emits light including vacuum ultraviolet light, and a part of the discharge vessel has a specific material (for example, two Only the outer tube of the discharge vessel having a heavy tube structure may be made of a specific material, and only the window member for light emission is made of a specific material. Of course, the entire discharge vessel is made of a specific material. It may have.

  Hereinafter, specific examples of the present invention will be described, but the present invention is not limited thereto.

[Example 1]
The fluorine content (concentration) is 7000 wt. An excimer having the configuration shown in FIG. 1 is formed by forming a discharge vessel using ppm synthetic quartz glass (raw material), disposing the inner and outer electrodes at predetermined positions and filling the discharge space with xenon gas. A lamp (hereinafter also referred to as “discharge lamp (A)”) was produced.
In this discharge lamp (A), the outer tube constituting element tube constituting the outer tube of the discharge vessel is produced according to the flowchart of FIG. 3, and is the same as the lamp 24 in Experimental Example 2.

  This discharge lamp (A) is continuously lit for 4000 hours under a lighting condition where the lamp power is 400 W, and the initial radiant intensity of vacuum ultraviolet light having a wavelength of 190 nm or less and the radiant intensity every 1000 hours are located 30 mm away from the lamp. And measured with a photometer. The results are shown by the plot “●” in FIG.

[Example 2]
The fluorine content (concentration) is 10500 wt. An excimer having the configuration shown in FIG. 1 is formed by forming a discharge vessel using ppm synthetic quartz glass (raw material), disposing the inner and outer electrodes at predetermined positions and filling the discharge space with xenon gas. A lamp (hereinafter also referred to as “discharge lamp (B)”) was produced.
In this discharge lamp (B), the outer tube constituting element tube constituting the outer tube of the discharge vessel is produced according to the flowchart of FIG. 4, and is the same as the lamp 47 in Experimental Example 4.

  With respect to this discharge lamp (B), the radiation intensity was measured in the same manner as in Example 1. The results are shown by the plot “◯” in FIG.

Example 3
In Example 2, an excimer lamp (hereinafter also referred to as “discharge lamp (C)”) was produced in the same manner as in Example 2 except that oxygen doping treatment was further performed after the OH group doping treatment.
This discharge lamp (C) is the same as the lamp 55 in Experimental Example 5.

  With respect to this discharge lamp (C), the radiation intensity was measured by the same method as in Example 1. The results are shown by the plot “□” in FIG.

[Comparative Example 1]
The fluorine content (concentration) is 7000 wt. An excimer having the configuration shown in FIG. 1 is formed by forming a discharge vessel using ppm synthetic quartz glass (raw material), disposing the inner and outer electrodes at predetermined positions and filling the discharge space with xenon gas. A lamp (hereinafter also referred to as “comparison discharge lamp (A)”) was produced.
In this comparative discharge lamp (A), the outer tube constituting base tube constituting the outer tube of the discharge vessel is produced according to the flowchart of FIG. 10, and the outer tube of the discharge vessel has the composition shown in FIG. I have it.

  With respect to this comparative discharge lamp (A), the radiation intensity was measured in the same manner as in Example 1. The results are shown by the plot “♦” in FIG.

From the results of Examples 1 to 3 and Comparative Example 1 described above, according to the discharge lamp according to the present invention, the radiation intensity of vacuum ultraviolet light is large, and high light radiation intensity characteristics can be maintained over a long period of time. confirmed.
Moreover, by satisfying the conditions (1) to (3), high light emission intensity and light emission intensity maintaining characteristics can be obtained, and the conditions (1), (2) and (4) must be satisfied. In some cases, it was confirmed that even higher light emission intensity and light emission intensity maintaining characteristics can be obtained as compared with the case where the conditions (1) to (3) are satisfied.
Furthermore, it was confirmed that by satisfying all the conditions (1) to (4), higher light emission intensity maintaining characteristics can be obtained.

It is sectional drawing for description which shows the outline of a structure in an example of the xenon excimer lamp which concerns on this invention. It is sectional drawing which shows a cross section perpendicular | vertical to the tube axis | shaft of a discharge vessel of the xenon excimer lamp shown in FIG. It is a flowchart which shows an example of the manufacturing process of the discharge vessel of the xenon excimer lamp shown in FIG. It is a flowchart which shows the other example of the manufacturing process of the discharge vessel of the xenon excimer lamp shown in FIG. It is explanatory drawing which shows the composition of the synthetic quartz glass which forms the heat processing body obtained in the heat treatment process in the manufacturing process of the discharge vessel of the xenon excimer lamp shown in FIG. It is explanatory drawing which shows the composition of the synthetic quartz glass which forms the oxygen dope process body obtained in the oxygen dope process in the manufacturing process of the discharge vessel of the xenon excimer lamp shown in FIG. It is explanatory drawing which shows the composition of the synthetic quartz glass which forms the OH group dope process body obtained in the OH group dope process in the manufacturing process of the discharge vessel of the xenon excimer lamp shown in FIG. The composition of synthetic quartz glass forming the discharge vessel of the xenon excimer lamp shown in FIG. 1, which is obtained by performing oxygen doping after the OH group doping treatment process according to the flowchart of FIG. It is explanatory drawing which shows a composition. It is a graph which shows the radiation intensity maintenance factor of the vacuum ultraviolet light of the discharge lamp which concerns on Example 1- Example 3 and Comparative Example 1. FIG. It is a flowchart which shows an example of the manufacturing process of the conventional discharge vessel made from synthetic quartz glass. It is explanatory drawing which shows the composition of the synthetic quartz glass which forms the discharge vessel made from the synthetic quartz glass manufactured according to the flowchart shown in FIG. It is a flowchart which shows the other example of the manufacturing process of the conventional discharge vessel made from synthetic quartz glass.

Explanation of symbols

20 Excimer lamp 21 Discharge vessel 22 Outer tube 23 Inner tube 24 Outer electrode 25 Inner electrode 26 Power supply device 27 Exhaust tube remainder H Discharge space

Claims (8)

In a discharge lamp comprising a discharge vessel made of synthetic quartz glass and emitting light containing ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel,
In at least a part of the discharge vessel, the content of fluorine in the synthetic quartz glass forming the discharge vessel is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, The discharge lamp is characterized in that the concentration of oxygen molecules in the synthetic quartz glass forming the surface layer of the surface is higher than the concentration of oxygen molecules in the synthetic quartz glass forming the thickness center portion. In the surface layer of the at least one surface in the discharge vessel, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer changes in the thickness direction from the thickness center portion side toward the surface,
2. The discharge lamp according to claim 1, wherein an average concentration of oxygen molecules in a thickness portion from the at least one surface to a depth of 200 μm is 0.8 × 10 ¹⁶ atoms / cc or more. In a discharge lamp comprising a discharge vessel made of synthetic quartz glass and emitting light containing ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel,
In at least a part of the discharge vessel, the content of fluorine in the synthetic quartz glass forming the discharge vessel is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, And the discharge lamp characterized by the density | concentration of OH group in the synthetic quartz glass which forms the surface layer of the said surface being higher than the density | concentration of OH group in the synthetic quartz glass which forms thickness center part. In the surface layer of the at least one surface in the discharge vessel, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer changes in the thickness direction from the thickness center portion side toward the surface,
The average concentration of OH groups in the thickness portion from the at least one surface to a depth of 100 μm is 70 wt. The discharge lamp according to claim 3, wherein the discharge lamp is at least ppm. In a light emitting device comprising a discharge lamp that radiates light including ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel, and having a light emission window made of synthetic quartz glass for emitting light from the discharge lamp,
In at least a part of the light emission window, the fluorine content in the synthetic quartz glass forming the light emission window is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, The light emitting device is characterized in that the concentration of oxygen molecules in the synthetic quartz glass forming the surface layer of the surface is higher than the concentration of oxygen molecules in the synthetic quartz glass forming the thickness center portion. In the surface layer of the at least one surface in the light emission window, the concentration of Si-F bonds in the synthetic quartz glass forming the surface layer changes in the thickness direction from the thickness center portion side toward the surface,
6. The light emitting device according to claim 5, wherein an average concentration of oxygen molecules in a thickness portion from the at least one surface to a depth of 200 μm is 0.8 × 10 ¹⁶ molecules / cc or more. In a light emitting device comprising a discharge lamp that radiates light including ultraviolet light having a wavelength of 190 nm or less inside the discharge vessel, and having a light emission window made of synthetic quartz glass for emitting light from the discharge lamp,
In at least a part of the light emission window, the fluorine content in the synthetic quartz glass forming the light emission window is 7000 wt. ppm to 30000 wt. The concentration of Si-F bonds in the synthetic quartz glass forming the surface layer is lower than the concentration of Si-F bonds in the synthetic quartz glass forming the thickness center on at least one surface, And the light emission apparatus characterized by the density | concentration of OH group in the synthetic quartz glass which forms the surface layer of the said surface being higher than the density | concentration of OH group in the synthetic quartz glass which forms thickness center part. In the surface layer of the at least one surface in the light emission window, the concentration of the Si-F bond in the synthetic quartz glass forming the surface layer is changed in the thickness direction from the thickness center side toward the outer surface,
The average concentration of OH groups in the thickness portion from the at least one surface to a depth of 100 μm is 70 wt. The light emitting device according to claim 7, wherein the light emitting device is at least ppm.

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