JP5857435B2 - Ultraviolet irradiation device, ultraviolet irradiation method, and method of manufacturing ultraviolet irradiation device - Google Patents

Description

  The present invention relates to an ultraviolet irradiation apparatus, an ultraviolet irradiation method, and a method of manufacturing such an ultraviolet irradiation apparatus for irradiating a panel (substrate to be processed) with ultraviolet rays, for example, for manufacturing a liquid crystal panel.

  As an ultraviolet irradiation device for manufacturing a liquid crystal panel, there is one having a configuration including an ultraviolet lamp and a water-cooled jacket tube provided outside the ultraviolet lamp and provided with an ultraviolet transmission filter inside. The ultraviolet region transmission filter is a spectral filter that transmits ultraviolet rays in a predetermined wavelength range required for the irradiated object. Since such a spectral filter itself deteriorates its ultraviolet transmission characteristics due to the ultraviolet light from the ultraviolet lamp, this ultraviolet irradiation device uses a predetermined wavelength range before the ultraviolet light from the ultraviolet lamp reaches the spectral filter. Further, a means for cutting short wavelength ultraviolet rays is required (see, for example, JP-A-6-267509). By such means, the ultraviolet output working characteristics can be improved as the ultraviolet irradiation device, and the life of the apparatus can be extended.

  The ultraviolet cut means in the above patent document is an ultraviolet cut filter obtained by adding a metal oxide that suppresses ultraviolet rays having a shorter wavelength to a glass or quartz material in advance or performing a process such as vapor deposition on the surface. In the above-mentioned patent document, such an ultraviolet cut filter is spatially positioned closer to the ultraviolet lamp than the ultraviolet transmission filter. This type of ultraviolet cut filter is laborious and expensive to manufacture.

  In addition to the above-described configuration, the ultraviolet irradiation device for manufacturing a liquid crystal panel has a short wavelength side in order to transmit ultraviolet rays in a predetermined wavelength range (for example, 320 nm to 380 nm) required for the irradiated object. A configuration in which the ultraviolet cut filter and the long wavelength side light cut filter are spatially arranged in tandem is also conceivable. Also in such a structure, what was formed by addition to the glass of a metal oxide as disclosed by said patent document, or the vapor deposition to the glass surface as an ultraviolet cut filter by the side of a short wavelength can be used. In this case, in equipment for manufacturing a large liquid crystal panel, it is possible to adopt a configuration in which ultraviolet cut filters are spread over a certain large area, but in that configuration, light leakage occurs at the abutting surface, or due to heat There is a possibility that stress is generated by expansion and contraction.

JP-A-6-267509

  An object of the present invention is, for example, in the manufacture of a liquid crystal panel, in an ultraviolet irradiation device for irradiating a panel (substrate to be processed) with ultraviolet rays, an ultraviolet irradiation method, and a method of manufacturing such an ultraviolet irradiation device. Another object of the present invention is to provide an ultraviolet irradiation apparatus, an ultraviolet irradiation method, and a method for manufacturing the ultraviolet irradiation apparatus, which are provided with an ultraviolet cut filter that has a high effect of cutting unnecessary ultraviolet rays and is low in cost.

In order to solve the above-described problems, an ultraviolet treatment apparatus according to one aspect of the present invention is a cylindrical metal halide lamp having a quartz glass-made arc tube, and a position surrounding the arc tube of the metal halide lamp in a cylindrical shape. An inner tube that is a first tube of quartz glass material provided, and an outer tube that is a second tube of quartz glass material provided in a position surrounding the inner tube in a cylindrical shape; A space in which the space between the first tube and the second tube is closed so that fluid can flow in the space between the first tube and the second tube. A double tube and a thickness of 0.3 μm or more formed on the outer surface of the outer tube of the double tube or on the surface of the inner tube of the double tube facing the metal halide lamp. .3 μm or less containing tantalum and 30% by weight to 5% by weight of titanium oxide And an oxide film contained at a ratio of 0% by weight or less. An ultraviolet treatment apparatus according to another aspect of the present invention includes a cylindrical metal halide lamp having a quartz glass-made arc tube, and a cylindrical shape provided at a position surrounding the arc tube of the metal halide lamp in a cylindrical shape. An inner tube that is a first tube made of a quartz glass material, and a cylindrical tube that is provided at a position surrounding the inner tube in a tubular shape, and an outer tube that is a second tube made of quartz glass material, A double tube that is a space in which the space between the first tube and the second tube is closed so that a fluid can flow in the space between the first tube and the second tube; A glass plate provided on the outer side of the double tube as viewed from the metal halide lamp and spaced from the double tube; and a film thickness of 0.3 μm or more formed on the surface of the glass plate; 3% or less, containing tantalum and containing 30% by weight or more and 50% by weight of titanium oxide And an oxide film containing it in a proportion of not more than% by weight. Moreover, the manufacturing method of the ultraviolet processing apparatus which is another aspect of this invention was provided in the position which surrounds the inner tube which is a 1st pipe | tube of a cylindrical shape and a quartz glass raw material, and this inner pipe | tube. An outer tube that is a cylindrical tube made of quartz glass material, and the first tube and the second tube so that a fluid can flow in a space between the first tube and the second tube. Providing a double pipe in which the space between two pipes is a closed space; and on the outer surface of the outer pipe of the double pipe or the closed of the inner pipe of the double pipe Applying a solution containing a solute containing 30% to 50% by weight of TiO ₂ and 1% to 15% by weight of Ta ₂ O ₅ on a surface that is not the side facing the open space ; The double pipe coated with the solution is heat-treated and deposited on the surface of the double pipe to form an oxide film containing titanium. And a step of disposing a metal halide lamp having a tubular, quartz glass-made arc tube inside the inner tube of the double tube in which the oxide film is formed. .

  According to the present invention, it is possible to provide an ultraviolet irradiating device, an ultraviolet irradiating method, and a method for manufacturing such an ultraviolet irradiating device, which are provided with a low-cost ultraviolet cutting filter that has a high effect of cutting unnecessary ultraviolet rays.

1 is a longitudinal sectional view showing a configuration of an ultraviolet irradiation device according to an embodiment of the present invention. Sectional drawing of the arrow direction in the A-Aa position shown in FIG. The longitudinal cross-sectional view which shows the structure of the metal halide lamp shown in FIG. The longitudinal cross-sectional view which expands and shows a part of illustration of FIG. The characteristic view which shows the example of the spectral distribution of the light which the metal halide lamp shown in FIG. 1 radiates | emits. The characteristic view which shows the example of the spectral transmittance of the oxide film (unnecessary ultraviolet cut filter) which the ultraviolet irradiation device shown in FIG. 1 has. , , The microscope picture which looked at the surface state of each area | region which differs in the axial direction in the water-cooled jacket tube as a comparative example in which the unnecessary ultraviolet-ray cut filter was formed on the outer surface. The characteristic view which shows the example of the spectral transmittance in each area | region which differs in the axial direction in the water cooling jacket tube as a comparative example in which the unnecessary ultraviolet-ray cut filter was formed on the outer surface. The characteristic comparison figure which shows how the characteristic shown in FIG. 6 changes with the thickness of an oxide film. The characteristic view which shows the example of the spectral distribution of the light which the ultraviolet irradiation device shown in FIG. 1 radiates | emits. The characteristic view which expands and shows the part below wavelength 360nm among illustrations shown in FIG. , The table | surface which shows the result example of the intensity | strength measurement of the ultraviolet-ray which the ultraviolet-ray irradiation apparatus shown in FIG. 1 radiates | emits. The characteristic view which shows the example of the spectral distribution of the light which the metal halide lamp shown in FIG. The characteristic view which shows the example of the spectral distribution of the light which the ultraviolet irradiation device shown in FIG. The characteristic view which expands and shows the wavelength of 360 nm or less among the illustrations shown in FIG. , The table | surface which shows the result example of the intensity | strength measurement of the ultraviolet-ray radiated | emitted by the ultraviolet irradiation device shown in FIG. 1 different from what was shown to FIG. The characteristic view which shows the exemplary spectral absorptance of the photoinitiator required for the resin composition hardened | cured favorably by the ultraviolet irradiation by the ultraviolet irradiation device shown in FIG. The longitudinal cross-sectional view which shows the structure of the ultraviolet irradiation device which is another embodiment of this invention. Sectional drawing of the arrow direction in B-Ba position shown in FIG. The characteristic view which compares and shows the example of the spectral transmittance of the oxide film (unnecessary ultraviolet cut filter) which the ultraviolet irradiation device shown in FIG. Results of evaluating the spectral characteristics (unnecessary ultraviolet ray cut characteristics, necessary ultraviolet ray transmission characteristics) and occurrence of cracks of various oxide films 16 obtained when the weight% of the film forming raw material of the oxide film 16 is changed are shown. table. The longitudinal cross-sectional view which shows the structure of the ultraviolet irradiation device which is another embodiment of this invention. Sectional drawing of the arrow direction in the C-Ca position shown in FIG. The characteristic view which shows the example of the spectral transmittance of the heat ray absorption filter which exists now. The characteristic view which shows the example of the spectral transmittance of the heat ray reflective filter shown in FIG. The characteristic view which shows the example of the spectral distribution of the ultraviolet-ray which the ultraviolet irradiation device as a modification of the ultraviolet irradiation device shown in FIG. 22 radiates | emits. The characteristic view which shows the example of the spectral distribution of the ultraviolet-ray which the ultraviolet irradiation device shown in FIG. 22 radiates | emits. The characteristic view which compares and shows the wavelength distribution of light emission when the metal seed | tip enclosed with a metal halide lamp is changed. For example, the absorbance when the concentration of a photoinitiator of 2,2-dimethoxy-1,2-diphenylethane-1-one in a solvent of chloroform is 0.1%, 0.01%, 0.001% FIG. The table | surface which compares and compares the ratio of the case where it acts on said photoinitiator with the metal halide lamp of a comparative example, and the case where it acts on said photoinitiator with the metal halide lamp of a more preferable example. The graph which compares and shows the spectral distribution of the light emission in a required ultraviolet region when the amount of enclosure of Zn (however, the amount converted into zinc iodide) in a metal halide lamp is changed. The table | surface which shows the integrated ultraviolet intensity of the specific wavelength range computed from the result of FIG. The graph which shows the change of the integrated ultraviolet-ray intensity | strength from wavelength 320nm to wavelength 340nm when the amount of enclosure of Zn (however, the quantity converted into zinc iodide) in a metal halide lamp is changed. The table | surface which compares and shows the ratio of resin hardening at the time of making it act on a photoinitiator with the metal halide lamp which changed the enclosure amount of Zn.

  While embodiments of the present invention will be described with reference to the drawings, the drawings are provided for purposes of illustration only and are not intended to limit the invention in any way.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing the configuration of an ultraviolet irradiation apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view in the direction of the arrow at the A-Aa position shown in FIG.

  As shown in FIGS. 1 and 2, the ultraviolet irradiation device includes a metal halide lamp 100 and a cooling unit 200. A predetermined interval is set between the metal halide lamp 100 and the cooling unit 200 (its double tube) by holders 111 and 112 attached to sockets 351 and 352 of the metal halide lamp 100.

  The metal halide lamp 100 will be described with reference to FIGS. 3 and 4. 3 is a longitudinal sectional view showing the configuration of the metal halide lamp shown in FIG. 1, and FIG. 4 is a longitudinal sectional view showing a part of FIG. 3 in an enlarged manner.

  As shown in FIGS. 3 and 4, the metal halide lamp 100 includes an arc tube 31 in which a discharge space 30 is formed of, for example, quartz glass having ultraviolet transparency. The arc tube 31 has a cylindrical shape, and electrodes 321 and 322 made of tungsten, for example, are arranged inside both ends in the longitudinal direction.

  The electrodes 321 and 322 are welded to one end of metal foils 341 and 342 made of, for example, molybdenum via inner leads 331 and 332, respectively. One end of an outer lead (not shown) is welded to the other end of the metal foils 341 and 342. The portions of the metal foils 341 and 342 are obtained by heating and sealing the arc tube 31 between the inner leads 331 and 332 and the outer leads. In addition to the rare gas, for example, mercury, iron, tin, and mercury iodide are sealed inside the arc tube 31.

  The metal foils 341 and 342 may be any material that has a thermal expansion coefficient close to that of the quartz glass forming the arc tube 31, but molybdenum is used as a material suitable for this condition. Lead wires 361 and 362 for power feeding, which are insulated and sealed in ceramic sockets 351 and 352, for example, are electrically connected to the other ends of the outer leads whose one ends are connected to the metal foils 341 and 342, respectively. Furthermore, the lead wires 121 and 122 are connected to a power supply circuit (not shown).

  The metal halide lamp 100 configured as described above can be, for example, compatible with a long arc having an outer diameter of 27.5 mm and a light emission length of 1000 mm. FIG. 5 is a characteristic diagram showing an example of a spectral distribution of light emitted from the metal halide lamp shown in FIG. More specifically, the spectral distribution is shown when the lamp voltage is 1310 V, the lamp current is 10.3 A, and the lamp power is 12 kW.

  Referring to FIGS. 1 and 2 again, the cooling unit 200 includes an inner tube 12 (inner diameter: 32 mm, outer diameter: 36 mm) made of quartz glass having the same ultraviolet transmittance as the arc tube 31 of the metal halide lamp 100, and an inner tube. 12 has a double tube provided with an outer tube 13 (inner diameter 64 mm, outer diameter 70 mm) made of quartz glass having the same ultraviolet light transmittance as that of the arc tube 31. The inner tube 12 is provided at a position surrounding the arc tube 31 in a cylindrical shape, and the outer tube 13 is provided at a position surrounding the inner tube 12 in a cylindrical shape. The space between the inner tube 12 and the outer tube 13 is a closed space so that a fluid can flow. Through this space, the connection tube 141 provided at the outer peripheral end is cooled to the connection tube 142 from the outside. It is possible to circulate the cooling water 15 having a water temperature of about 25 ° C. such as water as a medium for use.

  More specifically, the cooling water 15 having a low temperature is introduced from the connecting pipe 141, and the cooling water 15 heated by cooling the metal halide lamp 100 is discharged from the connecting pipe 142. The cooling unit 200 has a circulation structure as a whole so that the warmed cooling water 15 is re-cooled and re-entered from the connection pipe 141.

  The outer tube 13 is made of, for example, quartz glass containing at least 50% of SiO 2, and an oxide film 16 mainly composed of Ti is formed on the outer surface of the outer tube 13. The oxide film 16 is coated with an oxide solution as a raw material using a method such as dipping, and then heat-treated (baked or baked) at a high temperature of about 1100 ° C., for example, and uniformly fixed on the outer surface of the outer tube 13. , Which is attached.

  The application of the solution by dipping is performed by changing the direction of the double tube of the cooling unit 200 in the longitudinal direction and pulling it up from the tank containing the oxide solution a plurality of times. Thereby, the applied film thickness becomes uniform, leading to uniform formation of the oxide film 16.

  The oxide film 16 cuts unnecessary ultraviolet light having a wavelength of less than 320 nm out of light emitted from the metal halide lamp 100. For example, as shown in FIG. 6, the spectral characteristics have substantially the same spectral transmittance in the Ia region and Ib region of the double pipe of the cooling unit 200. This depends on the uniform film thickness of the oxide film 16 (the nominal film thickness in the case shown in FIG. 6 is 0.7 μm).

  FIGS. 7A, B, and C are photomicrographs showing the surface states of different regions in the axial direction of a water-cooled jacket tube as a comparative example in which an unnecessary ultraviolet cut filter is formed on the outer surface. Dipping is a relatively inexpensive film formation method. However, if the film thickness is thin, the effect of cutting ultraviolet rays having a wavelength less than a predetermined wavelength (eg, 320 nm) is not sufficient, and conversely, if the film is formed thick, cracks are likely to occur. Difficult to produce special characteristics. When a crack occurs, unnecessary ultraviolet rays leak from the crack, and the effect of cutting unnecessary ultraviolet rays is not sufficient. An example of the occurrence of such a crack will be described as a comparative example with reference to FIGS. 7A, B, C, and FIG. The unnecessary ultraviolet cut filter in this example is a filter formed by dipping a predetermined solution (solvent and solute) on the outer surface of the water-cooled jacket tube and then heat-treating it. In order to see the relationship between the film thickness and the occurrence of cracks, in dipping, the film thickness by dipping is intentionally changed in the axial direction of the water-cooled jacket tube.

  (II), (III), and (IV) of FIGS. 7A, 7B, and 7C show the surface states of the respective regions that are different in the axial direction of the water-cooled jacket tube in which such an unnecessary ultraviolet cut filter is formed on the outer surface. Is shown. Each region is shown corresponding to the side of the graph in FIG. In order from (II) to (IV), the film thickness of the ultraviolet cut filter is thicker, but as shown in FIGS. 7A, 7B, and 7C, cracks are prominent in the same directions (II) to (IV). It is. And as shown in the graph of FIG. 8, the characteristic of unnecessary ultraviolet-ray cut has deteriorated the (IV) side. FIG. 8 is a graph obtained by measuring the spectral transmittance of the unnecessary ultraviolet cut filter, and a plurality of graphs in (II), (III), and (IV) correspond to measurement results at different positions in each region. doing.

  The oxide film 16 shown in FIG. 1 and FIG. 2 generally varies in its ultraviolet cut characteristics depending on the ratio of the film forming raw material, the solution coating thickness condition, the heat treatment condition, and the like. By using this, it is possible to obtain a spectral filter having a desired ultraviolet cut characteristic within a certain range. When it is necessary to increase the thickness of the oxide film 16 in order to obtain a desired UV-cutting characteristic, the number of times of application of the raw material solution may be increased. Further, in order to improve the mechanical strength of the oxide film 16 formed in a thick film thickness, it is effective to add Ta as a film forming material (described later).

As a characteristic example, in the oxide film 16 formed when the weight ratio in the raw material solution is SiO ₂ : TiO ₂ : Ta ₂ O ₅ = 45: 45: 10, the transmittance is about 50% around a wavelength of 350 nm, A spectral filter having a transmittance of 5% or less near a wavelength of 320 nm can be obtained.

  FIG. 9 is a characteristic comparison diagram showing how the characteristics shown in FIG. 6 change depending on the thickness of the oxide film 16. From A to D in the figure, the characteristics when the film thickness is thick are shown. As shown in FIG. 9, by changing the film thickness of the oxide film 16, the ultraviolet cut characteristic can be varied with controllability.

  A liquid crystal panel manufacturing apparatus can be configured by using the above-described ultraviolet irradiation apparatus as one unit and using a plurality (for example, five units) of the apparatus. The liquid crystal panel manufacturing apparatus can emit light having a spectral distribution as shown in FIG. 10, for example, which is necessary in the liquid crystal panel manufacturing process. Thereby, in the liquid crystal panel manufacturing process, it is possible to emit ultraviolet light suitable for the process while suppressing adverse effects on the liquid crystal panel. FIG. 11 is an enlarged characteristic diagram illustrating a portion having a wavelength of 360 nm or less in the illustration shown in FIG. 10 and 11 show the results of measurement using a neutral density filter (measurement filter for reducing light intensity).

  12A and 12B are tables showing examples of results of measuring the intensity of ultraviolet rays emitted from the ultraviolet irradiation device shown in FIG. With reference to FIGS. 12A and 12B, the ultraviolet intensity in a wavelength range that has an adverse effect on a liquid crystal panel in the process of manufacturing in this ultraviolet irradiation apparatus will be described. The figure shows the result of measurement without passing through the neutral density filter.

  FIG. 12A shows the result of measurement with an intensity meter “UV-35” manufactured by Oak, for example, or an intensity meter “UVD-S365” manufactured by USHIO INC. Having a sensitivity peak at a wavelength of 340 nm to 400 nm. FIG. 12B is a result of measurement with an intensity meter “UV-31” manufactured by Oak, for example, having a sensitivity peak at a wavelength of 300 nm to 320 nm. It can be considered that the wavelength of ultraviolet rays that cause deterioration damage to a liquid crystal panel during production is less than 320 nm. On the other hand, the wavelength of ultraviolet rays required for a liquid crystal panel in the manufacturing process is, for example, 320 nm to 380 nm. Therefore, when the measurement result shown in FIG. 12A is 100%, the measurement result shown in FIG. 12B should be small, and specifically, 5% or less is preferable. More preferably, it is 1% or less.

12A is a result of the intensity meter with a sensitivity peak at a wavelength 340Nm～400nm, the intensity of light, up to ^{90mW / cm 2, 77.2mW / cm} 2 at a minimum, is 85.6mW / cm ² on average It is shown that. Further, 0.105MW FIG B, as a result by the intensity meter with a sensitivity peak at a wavelength 300Nm～320nm, the intensity of light, up to 0.118mW / cm ^2, a minimum 0.09mW / cm ^2, the average / Cm ² .

  Therefore, the comparison between the maximum values is about 0.13%, the comparison between the minimum values is about 0.12%, and the comparison between the average values is about 0.12%. These are even less than 1%, which is considered highly preferred. Therefore, according to this ultraviolet irradiation device, it is possible to irradiate ultraviolet rays having a desired wavelength while suppressing deterioration damage to the liquid crystal panel being manufactured.

  Next, FIG. 13 is a characteristic diagram showing an example of a spectral distribution of light emitted from the metal halide lamp shown in FIG. 1, which is different from FIG. In this case, the metal halide lamp 100 contains mercury and thallium iodide (TlI) in addition to the rare gas. The lighting conditions are a lamp voltage of 1.31 kW, a lamp current of 10.3 A, and a lamp power of 12 kW.

  FIG. 14 is a characteristic diagram showing an example of a spectral distribution of light emitted from the ultraviolet irradiation device shown in FIG. 1, which is different from FIG. 10, and specifically, a metal halide lamp 100 having the characteristics shown in FIG. 13 is used. In the case of the ultraviolet irradiation apparatus. Even with such spectrally distributed ultraviolet radiation, it is possible to irradiate ultraviolet rays suitable for the process while suppressing adverse effects on the liquid crystal panel being manufactured. FIG. 15 is a characteristic diagram showing an enlarged wavelength of 360 nm or less in the illustration shown in FIG. 14 and 15 show the results of measurement using a neutral density filter, similarly to the cases shown in FIGS. 10 and 11.

  16A and 16B are tables showing examples of measurement results of the intensity of ultraviolet rays emitted from the ultraviolet irradiation device shown in FIG. 1, which are different from those shown in FIGS. 12A and 12B. With reference to FIGS. 16A and 16B, the ultraviolet intensity in a wavelength region that has an adverse effect on a liquid crystal panel in the process of manufacturing in this ultraviolet irradiation apparatus will be described. 16A and 16B show the results of measurement without passing through the neutral density filter. In addition, about FIG. 16A and B, the intensity | strength meter used, its view, and evaluation are the same as that of description in FIG.

16A is a result of the intensity meter with a sensitivity peak at a wavelength 340Nm～400nm, the intensity of light, up to ^{83.3mW / cm 2, 71mW / cm} 2 at a minimum, is 78.4mW / cm ² on average It is shown that. Further, FIG. 16B, the result of the intensity meter with a sensitivity peak at a wavelength 300Nm～320nm, the intensity of light, up to at 0.093mW / cm ^2, minimum 0.077mW / cm ^2, the average 0.086mW / Cm ² .

  Therefore, the comparison between the maximum values is about 0.112%, the comparison between the minimum values is about 0.108%, and the comparison between the average values is about 0.110%. These are even less than 1% or less, which is considered highly preferred. Therefore, an ultraviolet irradiation device using a metal halide lamp in which thallium iodide is sealed can be irradiated with ultraviolet rays having a desired wavelength while suppressing deterioration damage to the liquid crystal panel being manufactured.

  Next, the wavelength of ultraviolet rays necessary for a liquid crystal panel during production will be described. This can be defined as the absorption wavelength band of the photoinitiator that starts curing the ultraviolet curable resin used when manufacturing the liquid crystal panel, and is, for example, 320 nm to 380 nm. An example of such a photoinitiator is 2,2-dimethoxy-2-phenylacetophenone. The light absorption characteristic of this photoinitiator is shown in FIG. In FIG. 17, “0.0020%” and “0.0011%” indicate the concentration in the resin. In FIG. 17, a large absorption characteristic is shown in the wavelength range of 200 nm. However, the substance functions as a photoinitiator due to ultraviolet absorption at 320 nm to 380 nm, which is the wavelength of the actually irradiated ultraviolet rays.

  In the above embodiment, since the unnecessary ultraviolet cut filter by the oxide 16 is formed on the outer surface of the outer tube 13 of the double tube, light leakage from the butt surface, which becomes a problem when irradiating a large area, It is possible to suppress problems such as cracks caused by collision between filters due to expansion and contraction due to heat. Further, since the unnecessary ultraviolet cut filter can be formed by applying a raw material solution to the surface of various shapes and heat-treating it, there is an advantage that the degree of freedom of formation is high and the cost is low. In the sense that the degree of freedom of formation is high, the unnecessary ultraviolet cut filter made of the oxide 16 can be formed on the surface of the double tube inner tube 12 facing the metal halide lamp 100.

  The following modifications can be added to this embodiment. The case where the oxide film 16 is formed on the outer surface of the outer tube 13 has been described. However, as already described, the oxide film 16 is formed on the surface of the double tube inner tube 12 facing the metal halide lamp 100. Further, both of them may be formed. In addition, it is conceivable to form the oxide film 16 on the surfaces of the inner tube 12 and the outer tube 13 facing the coolant. In this case as well, a method of forming the oxide film 16 may be a method in which the raw material solution is applied by a method such as dubbing and then heat-treated and fixed.

  As described above, the dipping of the raw material solution can be performed so that the double pipe of the cooling unit 200 is changed in the longitudinal direction and pulled out from the tank containing the oxide solution a plurality of times. However, the following method can also be adopted. That is, instead of coating the entire length of the outer tube 13 at once, it may be performed, for example, every half. More specifically, the first coating is performed up to the middle of the outer tube 13, and the second coating is performed from the opposite side to the middle of the outer tube 13. At that time, in order to avoid the occurrence of a region in which the dipping region is insufficient and the ultraviolet ray cutting characteristic is inadequate, it is preferable that the dipping is performed so that the films partially overlap at the center in the longitudinal direction of the outer tube 13. According to this, even in the case of a longer outer tube 13, dipping with a uniform film thickness as a whole is possible. In order to obtain a more uniform film thickness, the above first and second operations may be performed once again (that is, a total of four coatings).

  Next, FIG. 18 is a longitudinal sectional view showing the configuration of an ultraviolet irradiation device according to another embodiment of the present invention, and FIG. 19 is a sectional view in the direction of the arrow at the B-Ba position shown in FIG. It is. The same reference numerals are given to the same components as those of the embodiment already described, and the description thereof is omitted.

  In this embodiment, an oxide film is not formed on the outer surface of the double tube of the cooling unit 200, but on the surface of the ultraviolet light transmissive glass plate 162 that is disposed opposite to the outer tube 13 of the cooling unit 200. An oxide film 161 mainly composed of Ti is formed. The oxide film 161 can be formed with a film thickness having a desired spectral transmission characteristic by a technique such as printing.

  The oxide film 161 can be formed on the back surface of the glass plate 162 in addition to being formed on the surface (front surface) of the glass plate 162 facing the cooling unit 200 as shown. Furthermore, you may form on both surfaces.

  In the case of this embodiment, since the oxide film 161 is formed by printing the raw material solution on the glass plate 162 that is transmissive to ultraviolet rays and then performing heat treatment, the film thickness can be easily adjusted at the time of printing. is there. This makes it easy to obtain desired spectral transmission characteristics as the oxide film 161.

  As a modification, a heat ray absorption filter may be further added to the ultraviolet irradiation apparatus shown in FIG. By providing a heat ray absorption filter that is a kind of optical filter, it is possible to more reliably cut light of, for example, 400 nm or more that is not necessary for the irradiated object. Such a heat ray absorption filter can be provided in the double pipe of the cooling unit 200 shown in FIG. More specifically, the inner tube 12 can be positioned in a space between the inner tube 12 and the outer tube 13 of the double tube so as to surround the tube. By providing in a double pipe, this heat ray absorption filter is suppressed from overheating with a heat ray.

  As another modification, an optical filter of the oxide film 161 may be provided on the glass plate 162, and a heat ray reflective filter may be further provided. Also in this case, by additionally providing a heat ray reflection filter, which is a kind of optical filter, it is possible to more reliably cut light of, for example, 400 nm or more that is not necessary for the irradiated object. About a heat ray reflective filter, the thing of a structure which is demonstrated by embodiment (FIG. 22) mentioned later can be utilized.

  Further, as the light emitting metal sealed in the metal halide lamp 100, any metal that can emit ultraviolet light having a wavelength of, for example, 320 nm to 380 nm can be employed.

  Next, the film thickness and the manufacturing process of the oxide film 16 (or the oxide film 161) in the ultraviolet irradiation apparatus described above will be described supplementarily below. Although it has already been described that the ultraviolet cut characteristic can be varied with controllability by changing the film thickness of the oxide film 16, the preferable film thickness range will be described more specifically.

FIG. 20 is a characteristic diagram showing an example of the spectral transmittance of the oxide film (unnecessary ultraviolet cut filter) included in the ultraviolet irradiation apparatus shown in FIG. As the formed film thickness, six types of 0.1 μm, 0.3 μm, 0.5 μm, 1.0 μm, 1.3 μm, and 1.5 μm were prepared and measured. In the case of the oxide film 16 showing the transmission characteristics in FIG. 6 and the like, the film thickness is 0.7 μm as described above, and the film forming raw material is SiO ₂ : TiO ₂ : Ta ₂ O ₅ = A solute having a weight ratio of 45:45:10 is dissolved in a predetermined solution. Moreover, the film thickness of these formed oxide films can be measured using, for example, a transmission electron microscope (TEM).

  As can be seen from FIG. 20, as the film thickness increases to 1.5 μm, the ultraviolet cut characteristic shifts to the longer wavelength side as compared with the ultraviolet cut characteristic when the film thickness is 0.1 μm. To go. Considering the actually required spectral characteristics, when the film thickness is 0.3 μm to 1.3 μm, it transmits the necessary ultraviolet light (wavelength 320 nm to 380 nm) and cuts unnecessary ultraviolet light (wavelength less than 320 nm). It is considered preferable.

  That is, when the film thickness is less than 0.3 μm, it can be seen that unnecessary ultraviolet rays cannot be sufficiently cut. On the other hand, when the film thickness exceeds 1.3 μm, the function of sufficiently transmitting the necessary ultraviolet rays is impaired.

  Regarding the preferable film thickness of the oxide film 16, it is necessary to consider its mechanical fastness (resistance to crack generation). For this purpose, it has already been described that it is effective to add Ta as a film forming raw material of the oxide film 16, but this point is also shown in FIG. Note that the inventors have obtained a feeling that it is better to make the film thickness 0.5 μm or more and 1.0 μm or less practically considering the unnecessary ultraviolet ray cut characteristics and mechanical characteristics of the oxide film 16. .

FIG. 21 evaluates the spectral characteristics (unnecessary ultraviolet ray cut characteristics, necessary ultraviolet ray transmission characteristics) and occurrence of cracks of various oxide films 16 obtained when the weight% of the film forming raw material of the oxide film 16 is changed. It is a table | surface which shows the result. An oxide film 16 was formed using a solution containing a solute in which the respective weight percentages of TiO ₂ and Ta ₂ O ₅ were changed as film forming materials. The remaining weight% is SiO _2. The formed film thickness is 0.7 μm.

  In FIG. 21, “×” indicates that it cannot be used (impossible), “○” indicates that it can be used (allowed), and “◎” indicates that it is particularly excellent (good). Is shown.

From the conclusion of the results shown in FIG. 21, when TiO ₂ is 30 wt% to 50 wt% and Ta ₂ O ₅ is 1 wt% to 15 wt%, there is no impossibility as spectral characteristics, And since there is no impossibility as a crack generation, it can be evaluated that there is no impossibility as a whole of them. Further, it is considered that the case where TiO ₂ is 40 wt% to 50 wt% and Ta ₂ O ₅ is 5 wt% to 15 wt% is even better. Note that the occurrence of cracks almost uniformly decreases as the content of Ta ₂ O ₅ increases, and the effect of adding Ta ₂ O ₅ to the film forming raw material is shown.

  Next, a schematic process for manufacturing the ultraviolet irradiation apparatus described above will be described.

  First, a double pipe having an inner pipe 12 and an outer pipe 13 as shown in FIG. 1 is prepared. Next, on the outer surface of the outer tube 13 of the double tube or the surface that is not the side facing the closed space of the inner tube 12 of the double tube, the solute that is the film forming raw material of the oxide film 16 is applied. The contained solution is applied by dipping, for example. The solute is selected from those having a preferable raw material ratio (greater than or equal to ○) described with reference to FIG.

  Subsequently, the double tube to which the solution has been applied is subjected to heat treatment, and is deposited on the surface of the double tube, so that the oxide film 16 is formed (baked) to a predetermined thickness. This predetermined film thickness is a preferable film thickness described with reference to FIG. Although the explanation is mixed, in the above dipping, the coating film thickness of the solution is controlled so as to be formed in such a preferable film thickness. Ti and Si remain in the oxide film 16 obtained by the heat treatment, but Ta remains only slightly. This is considered to be because Ta is diffused into the air by heat treatment. However, the presence of Ta during the heat treatment contributes to the formation of a highly uniform film in which cracks are unlikely to occur. This contribution point is as shown in FIG.

  After the oxide film 16 is formed on the double tube, next, the metal halide lamp 100 having a cylindrical, quartz glass-made arc tube 31 is arranged inside the inner tube 12 of the double tube. As described above, the ultraviolet irradiation apparatus shown in FIG. 1 can be manufactured.

  Next, still another embodiment will be described with reference to FIGS. FIG. 22 is a longitudinal sectional view showing a configuration of an ultraviolet irradiation apparatus as still another embodiment of the present invention, and FIG. 23 is a sectional view in the direction of the arrow at the C-Ca position shown in FIG. . 22 and 23, the same reference numerals are given to the components already described, and the description thereof will be omitted unless there are additional items.

In the arc tube 31 of this embodiment, a rare gas (argon) of 1.3 kPa, which is sufficient to stabilize the startability of the lamp, is sealed, and mercury is 0.9 mg / cm ³ , iodine. Mercury halide is enclosed in 0.08 mg / cm ³ , iron in 0.01 mg / cm ³ , and tin in 0.005 mg / cm ³ .

  As the enclosure of the metal halide lamp 100, thallium iodide (TlI) may be added or enclosed instead of iron. According to this, as shown in FIG. 14, the intensity of ultraviolet rays having wavelengths of 352 nm and 378 nm is newly increased, and the intensity of a necessary ultraviolet region can be increased. FIG. 14 is a characteristic diagram showing an example of the spectral distribution of light emitted from the metal halide lamp shown in FIG.

  As for how the spectral transmittance characteristic of the oxide film 16 shown in FIG. 22 changes depending on its thickness, the already explained FIG. 9 can be referred to. As shown in FIG. 9, by changing the film thickness of the oxide film 16, the ultraviolet cut characteristic can be varied with controllability.

  A liquid crystal panel manufacturing apparatus can be configured by using the above-described ultraviolet irradiation apparatus as one unit and using a plurality (for example, five units) of the apparatus. This liquid crystal panel manufacturing apparatus can emit light having a spectral distribution as shown in FIG. 10 already described, which is necessary in the liquid crystal panel manufacturing process. Thereby, in the liquid crystal panel manufacturing process, it is possible to emit ultraviolet light suitable for the process while suppressing adverse effects on the liquid crystal panel.

  For an example of the result of measuring the intensity of ultraviolet rays emitted from the ultraviolet irradiation device shown in FIG. 22, reference can be made to FIGS. 12A and 12B described above. About FIG. 12A and B, the intensity meter used, its view, and evaluation are as having already demonstrated.

Referring to FIGS. 22 and 23 again, reference numeral 17 denotes a heat ray reflection filter that is a kind of optical filter disposed between the cooling unit 200 and the liquid crystal panel 18 that is an object to be irradiated. The heat ray reflective filter 17 is a film (may be a multilayer) made of, for example, SiO ₂ and ZrO ₂ or CeO ₂ and SiO _2, and can be formed on, for example, a glass plate.

  By providing the heat ray reflective filter 17, it is possible to prevent visible light and infrared light (heat rays) having a wavelength of about 400 nm or more, which are unnecessary light, emitted from the metal halide lamp 100 from reaching the irradiated object. As shown in FIG. 25, the heat ray reflection filter 17 has improved transmittance in the wavelength region from 360 nm to 380 nm as compared with the existing heat ray absorption filter having spectral transmission characteristics as shown in FIG. . Therefore, according to the ultraviolet irradiation apparatus provided with the heat ray reflective filter 17, it is possible to improve the ultraviolet intensity of wavelengths 360 nm to 380 nm included in a necessary wavelength range.

  FIG. 26 shows an example of the spectral distribution of the irradiation light when the oxide film 16 and the heat ray absorption filter (arranged in the double tube) are combined, and FIG. 27 shows the combination of the oxide film 16 and the heat ray reflection filter 17. The example of the spectral distribution of the irradiation light in the case is shown. As can be seen by comparing these figures, in the combination using the heat ray reflective filter 17, the integrated energy at a wavelength of 340 to 380 nm is significantly increased.

  By providing the heat ray reflection filter 17 as described above, it is possible to maintain the effect of preventing heat rays and to easily dispose it in a relatively wide area between the metal halide lamp 100 and the irradiated object. There is an advantage that can be. For this reason, the structural burden in the region close to the metal halide lamp 100 is reduced, and for example, a reflector can be provided to efficiently use ultraviolet rays.

  In addition, it supplements about the heat ray absorption filter mentioned by description with reference to FIG. Such a heat ray absorption filter can be provided in the double pipe of the cooling unit 200 shown in FIG. 22 as mentioned above. More specifically, the inner tube 12 can be positioned in a space between the inner tube 12 and the outer tube 13 of the double tube so as to surround the tube. By providing in a double pipe, this heat ray absorption filter is suppressed from overheating with a heat ray.

  Next, modified examples of the inclusions included in the metal halide lamp 100 used in each embodiment described above will be described below. By changing the inclusion, the necessary radiation intensity of ultraviolet light having a wavelength of, for example, 320 nm to 380 nm can be increased.

First, as an enclosure in the metal halide lamp 100, in addition to a rare gas (argon), mercury (Hg), iron (Fe), thallium iodide (TlI), tin (Sn), zinc iodide (ZnI ₂ ), iodine The case where mercury halide (HgI ₂ ) is enclosed will be described.

  Such a metal halide lamp has Fe, Tl, Sn, Zn, and Hg as metals having light emission characteristics in the ultraviolet region. The ultraviolet rays produced by the metal halide lamp are, of course, effective for the ultraviolet curable resin composition, and the polymerization of the resin can be started by acting on the photoinitiator contained in the resin composition.

As an example, a metal halide lamp 100 (volume 490 cm ³ ) having a diameter φ of 27.5 mm, a wall thickness m of 1.5 mm, and a light emission length L of 1000 mm was prepared. One of them is a metal halide lamp as a comparative example in which 9 mg of Fe, 2 mg of Sn, and 45 mg of HgI ₂ are added in a small amount in an arc tube 31 and Hg is added in an amount of 1.04 mg / cm ^3. and then, as a more preferable example is another, the Fe in the arc tube 31 9 mg, the Sn 2 mg, a HgI ₂ 40 mg, and TlI 5 mg, the amount of the ZnI ₂ 12 mg, dopants sealed, the Hg added 1 A metal halide lamp having a sealed amount of 0.000 mg / cm ³ was obtained.

  A comparison between the comparative example and the preferred example is shown in FIG. FIG. 28 is a characteristic diagram showing a comparison of light emission wavelength distributions when the metal species sealed in the metal halide lamp is changed. In this characteristic diagram, the input power to the metal halide lamp is 1200 W.

  As shown in FIG. 28, it can be seen that the metal halide lamp of the preferred example radiates ultraviolet rays that are cumulatively stronger in the band of wavelengths of 320 to 380 nm than the metal halide lamp of the comparative example.

  In FIG. 29, for example, the concentration of the photoinitiator of 2,2-dimethoxy-1,2-diphenylethane-1-one in a solvent of chloroform was set to 0.1%, 0.01%, and 0.001%. It is a characteristic view which shows the light absorbency in the case. As shown in the figure, when the concentration of the photoinitiator with respect to the solvent is 0.1%, there is a high absorbance in the wavelength range of 320 to 380 nm.

  Therefore, FIG. 30 compares resin curing ratios when the photoinitiator is acted on by the metal halide lamp of the comparative example and when the photoinitiator is acted on by the metal halide lamp of the more preferable example. It is a table shown.

That is, when the ratio of the resin curing performed by irradiation of the photoinitiator by the metal halide lamp of the comparative example using Fe, Sn, HgI ₂ , and Hg as an enclosure is 100, Fe, Sn, HgI ₂ , TlI, ZnI _2. The ratio of resin curing performed by irradiation of the photoinitiator with a metal halide lamp of a more preferable example using Hg as an inclusion is 121. Therefore, according to the metal halide lamp of a more preferable example, it is possible to increase the curing rate of the ultraviolet curable resin and contribute to the productivity improvement of the liquid crystal panel and the like.

Next, as another more preferred embodiment, the amount of the Fe in the arc tube 31 9 mg, the Sn 2 mg, a HgI ₂ 25 mg, 3 mg of TlI, the ZnI ₂ 6 mg (typical value), and trace additives encapsulated added Thus, a metal halide lamp 100 (volume: 490 cm ³ ) having an enclosed amount of Hg of 1.00 mg / cm ³ was prepared. This will be described below.

FIG. 31 is a graph showing a comparison of spectral distributions of light emission in the necessary ultraviolet region when the amount of enclosed Zn (in terms of zinc iodide) in such a metal halide lamp is changed. When 6 mg of ZnI ₂ is sealed as described above, this corresponds to a concentration of about 12.2 μg / cm ³ . FIG. 32 is a table showing the integrated ultraviolet intensity in the specific wavelength region calculated from the results of FIG. As shown in FIG. 32, even if any of wavelength 320 nm to wavelength 340 nm, wavelength 320 nm to wavelength 360 nm, and wavelength 320 nm to wavelength 380 nm included in the necessary ultraviolet wavelength range is evaluated, the greater the amount of Zn enclosed, the greater the wavelength The UV intensity of the region is high.

FIG. 33 is a graph showing a change in integrated ultraviolet intensity from a wavelength of 320 nm to a wavelength of 340 nm when the amount of enclosed Zn (in terms of zinc iodide) in the metal halide lamp is changed. From the results shown in FIG. 33, it can be seen that the integrated ultraviolet intensity in this wavelength region reaches its peak when Zn exceeds 25 μg / cm ³ and does not increase any more. Therefore, the amount of Zn added to increase the intensity of ultraviolet rays having a necessary wavelength can be temporarily set to a range from 2 μg / cm ³ , which is the minimum value in the data, to 25 μg / cm ³ which reaches a peak. Even if it exceeds 25 μg / cm ³ , there is an effect in that sense. However, if the amount of Zn increases in the arc tube 31, there is an adverse effect, and further increase in the concentration is not preferable. That is, if Zn increases, the evaporation of Zn in the arc tube 31 does not easily occur, and unstable light emission such as separated light emission may occur.

  FIG. 34 is a table showing a comparison of resin curing ratios when applied to the photoinitiator with a metal halide lamp in which the amount of enclosed Zn is changed. This table is, of course, consistent with the results shown in FIG. 32 from the wavelength of 320 nm to the wavelength of 380 nm (the required wavelength range is 320 nm to 380 nm).

Another example of a more preferable metal halide lamp described with reference to FIGS. 31 to 34 described above includes Tl (thallium) as an enclosure. The relationship between the addition concentration of Tl and the addition concentration of Zn for obtaining a preferable effect will be supplemented below. When the additive concentration of Zn is increased, as shown in FIG. 31, the intensity of ultraviolet light having a wavelength of 352 nm or 378 nm, which is an emission wavelength due to Tl, decreases. Compared with the case where Zn is not added, when 15 μg / cm ^{3 of} Zn (in terms of zinc iodide) is added, the intensity of these wavelengths is reduced by about 20%.

In addition to the integrated intensity in the necessary wavelength region, in a metal halide lamp in which Tl is enclosed, a preferable concentration ratio between Zn and Tl can be considered from this viewpoint. As described above, when the amount of Zn (amount converted to zinc iodide, hereinafter the same) is 2 μg / cm ³ to 25 μg / cm ³ , Tl (converted to thallium iodide) is set to 3 mg in the arc tube 31. The amount of addition) can be calculated from 0.24 to 3 times the amount of Zn added.

  It is understood that the present invention is not limited to the specific embodiments illustrated and described herein, but includes all modifications that fall within the scope of the following claims.

  DESCRIPTION OF SYMBOLS 100 ... Metal halide lamp, 200 ... Cooling unit, 111, 112 ... Holder, 12 ... Inner tube, 13 ... Outer tube, 141, 142 ... Connection tube, 15 ... Cooling water, 16, 161 ... Oxide film, 17 ... Heat ray reflective filter 162, glass plate, 30, discharge space, 31, arc tube, 321, 322, electrode, 331, 332, inner lead, 341, 342, metal foil, 351, 352, socket, 361, 362, lead wire.

Claims (9)

A metal halide lamp having an arc tube made of a tubular, quartz glass material;
A cylindrical tube provided at a position surrounding the arc tube of the metal halide lamp in a cylindrical shape, an inner tube which is a first tube made of quartz glass material, and a tube provided at a position surrounding the inner tube in a cylindrical shape And an outer tube, which is a second tube made of quartz glass material, and the first tube and the second tube so that fluid can flow in a space between the first tube and the second tube. A double pipe that is a space in which the space between the two pipes is closed;
A film thickness of 0.3 μm or more and 1.3 μm or less formed on the outer surface of the outer tube of the double tube or the surface of the inner tube of the double tube facing the metal halide lamp, And an oxide film containing tantalum and containing 30% by weight or more and 50% by weight or less by weight of titanium oxide.   An optical filter having a property of cutting at least heat rays, provided in the space between the inner tube and the outer tube of the double tube so as to surround the inner tube in a cylindrical shape. The ultraviolet irradiation device according to claim 1, further comprising: A glass plate provided on the outer side of the double tube as viewed from the metal halide lamp and spaced from the double tube;
The ultraviolet irradiation device according to claim 1, further comprising: an optical filter formed on the surface of the glass plate and having a characteristic of cutting at least heat rays. A metal halide lamp having an arc tube made of a tubular, quartz glass material;
A cylindrical tube provided at a position surrounding the arc tube of the metal halide lamp in a cylindrical shape, an inner tube which is a first tube made of quartz glass material, and a tube provided at a position surrounding the inner tube in a cylindrical shape And an outer tube, which is a second tube made of quartz glass material, and the first tube and the second tube so that fluid can flow in a space between the first tube and the second tube. A double pipe that is a space in which the space between the two pipes is closed;
A glass plate provided on the outer side of the double tube as viewed from the metal halide lamp and spaced from the double tube;
An oxide film formed on the surface of the glass plate, having a film thickness of 0.3 μm or more and 1.3 μm or less, containing tantalum and containing 30% by weight to 50% by weight of titanium oxide. An ultraviolet irradiation device comprising:   An optical filter having a property of cutting at least heat rays, provided in the space between the inner tube and the outer tube of the double tube so as to surround the inner tube in a cylindrical shape. The ultraviolet irradiation device according to claim 4, further comprising:   The ultraviolet irradiation device according to claim 4, further comprising an optical filter formed on the surface of the glass plate and having a characteristic of cutting at least heat rays. Providing a resin composition containing a photoinitiator having an absorption region at a wavelength of 320 nm to 380 nm;
A cylindrical metal halide lamp having an arc tube made of quartz glass material, an inner tube which is a cylindrical tube provided at a position surrounding the arc tube of the metal halide lamp in a cylindrical shape, and a first tube made of quartz glass material; A cylindrical tube provided at a position surrounding the inner tube, and an outer tube that is a second tube made of quartz glass material, and a space between the first tube and the second tube. A double pipe in which the space between the first pipe and the second pipe is closed so that a fluid can flow, and an outer surface of the outer pipe of the double pipe, or the second pipe 30% by weight or more of tantalum containing titanium oxide with a thickness of 0.3 μm or more and 1.3 μm or less formed on the surface of the inner tube facing the metal halide lamp of the inner tube From an ultraviolet irradiation device having an oxide film contained in a proportion of 50% by weight or less, And a step of irradiating the resin composition with ultraviolet rays. Providing a resin composition containing a photoinitiator having an absorption region at a wavelength of 320 nm to 380 nm;
A cylindrical metal halide lamp having an arc tube made of quartz glass material, an inner tube which is a cylindrical tube provided at a position surrounding the arc tube of the metal halide lamp in a cylindrical shape, and a first tube made of quartz glass material; A cylindrical tube provided at a position surrounding the inner tube, and an outer tube that is a second tube made of quartz glass material, and a space between the first tube and the second tube. A double pipe which is a space in which the space between the first pipe and the second pipe is closed so as to allow fluid to flow; and the second pipe outside the double pipe as viewed from the metal halide lamp. A glass plate provided apart from the heavy tube, and a tantalum film having a thickness of 0.3 μm or more and 1.3 μm or less formed on the surface of the glass plate and containing 30% by weight of titanium oxide. UV irradiation having an oxide film containing at least 50% by weight Irradiating the resin composition with ultraviolet rays from the apparatus through the glass plate of the ultraviolet irradiation apparatus. An inner tube that is a cylindrical tube, a first tube made of quartz glass material, and an outer tube that is a second tube made of quartz glass material, provided in a position surrounding the inner tube in a tubular shape, A double tube in which the space between the first tube and the second tube is a closed space so that a fluid can flow in the space between the first tube and the second tube The process of preparing
The double tube of the outer tube outer surface, or on the double tube the inner tube said closed on the face of not facing the side to the space side of the comprises 50 wt% of TiO ₂ from 30 wt% And applying a solution containing a solute containing 1 to 15% by weight of Ta ₂ O ₅ ;
Heat-treating the double tube coated with the solution, depositing on the surface of the double tube, and forming an oxide film containing titanium;
And a step of disposing a metal halide lamp having an arc tube made of quartz glass material inside the inner tube of the double tube on which the oxide film is formed. Method.

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