JP2018190686A - Ultraviolet light source device and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a vacuum ultraviolet light source device which has a simple configuration at low cost, easy assembly repairing and excellent light emission efficiency.SOLUTION: A vacuum ultraviolent light source device is formed of: a light emitting structure having at least one light emitting tube consisting of a fine tube made of ultraviolet transmitting glass having thickness of 50 to 70 μm, into which discharge gas emitting ultraviolet light is sealed; and an electrode structure in which at least a pair of discharge electrodes extending to both sides across a gap constituting a discharge gap is arranged on one surface of an insulation substrate having ultraviolet resistance. The light emitting structure is formed by arranging it on the electrode structure in a direction in which the light emitting tube crosses a gap.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultraviolet light source device using gas discharge, and more particularly to a new ultraviolet light source device that emits vacuum ultraviolet light accompanying gas discharge and a method for manufacturing the same.

  Conventionally, high-pressure mercury lamps and excimer discharge lamps are well known as ultraviolet light source devices using gas discharge. Further, an external electrode type gas discharge device having a thin tube structure using an ultraviolet light emitting phosphor has recently been proposed as a new ultraviolet light source device (see, for example, Patent Documents 1 and 2). Further, an ultraviolet transmissive glass for an ultraviolet light source has been proposed (see, for example, Patent Document 3).

Japanese Patent Laid-Open No. 2016-2225070 (Shikko Giken) Japanese Patent Laid-Open No. 2017-027912 (Shikko Giken) Japanese Patent Laid-Open No. 2015-193521 (Nippon Electric Glass)

  However, the conventional high-pressure mercury lamp and halogen lamp have a problem that an expensive quartz glass envelope is required to transmit the generated ultraviolet rays. In addition, quartz glass has a drawback that it has a high softening point and is difficult to process. On the other hand, the ultraviolet light source device disclosed in Patent Documents 1 and 2 has a configuration mainly composed of an elongated borosilicate glass tube having an ultraviolet phosphor layer formed therein, and has a high degree of freedom in device design and is inexpensive. Features that can be manufactured. However, an inexpensive light source device that can directly emit vacuum ultraviolet rays accompanying gas discharge has not yet been realized.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an ultraviolet light source device that uses an external electrode type gas discharge that emits vacuum ultraviolet rays having a wavelength of 100 to 200 nm and that is inexpensive and has a simple configuration. To do. Another object of the present invention is to provide a new vacuum ultraviolet light source device based on the findings from the borosilicate ultraviolet transparent glass disclosed in Patent Document 3.

  Briefly, the present invention relates to a light-emitting structure mainly composed of an envelope made of a thin ultraviolet-transmitting glass having a thickness of 100 μm or less on the irradiation surface side in which a discharge gas that emits ultraviolet rays is enclosed, and the light-emitting structure A new type of light source device for vacuum ultraviolet light emission is provided, in which an electrode structure for applying an alternating drive voltage is formed as an independent part and is superposed in a capacitively coupled manner.

  That is, the present inventors, based on experience in developing an ultraviolet light source device having a thin tube structure using ultraviolet phosphors disclosed in Patent Documents 1 and 2, have made commercially available boron silicate glass thin by reducing the thickness of the glass thin tube. Even so, it was confirmed that a sufficient transmittance of 70% or more with respect to ultraviolet rays in the UV-C band (wavelength 250 to 270 nm) was obtained, and practical application of a deep ultraviolet light source device in this wavelength region was achieved. However, in the conventional borosilicate glass, the transmittance of vacuum ultraviolet rays of 100 to 200 nm is 20% or less even when the wall thickness is reduced, and it is difficult to release the vacuum ultraviolet rays outside the envelope. On the other hand, in Patent Document 3, the existence of a borosilicate ultraviolet transmissive glass different from the above was perceived as having a transmittance of 50% or more at a wavelength of 200 nm even with a thickness of 1 mm. However, a glass envelope having a transmittance of less than 50% is not suitable for commercialization of an ultraviolet light source device, particularly a vacuum ultraviolet light source device.

  Thus, the present invention provides a borosilicate ultraviolet transmissive glass having a thickness of 100 μm with a transmittance of 80% or more for ultraviolet light having a wavelength of 250 nm at a thickness of 1 mm, while having a transmittance of 70% or less for ultraviolet light having a wavelength of 200 nm. Hereinafter, in a discharge device in which the envelope is configured to be thinned to a range of 70 μm to 50 μm particularly preferably, a vacuum ultraviolet ray having a wavelength of 200 nm or less accompanying discharge of gas enclosed therein is 70% or more which is a standard for practical use. It was successfully taken out directly with transmittance. The shape of the glass envelope that is the main component of the light emitting structure may be a flat elliptical shape, a circular shape, a rectangular tube shape, or a flat panel shape. Since the thickness of the glass is extremely thin and the mechanical strength is weak, it is difficult to form the electrode directly on the envelope as in the case of a conventional discharge lamp. However, in the light source device of the present invention, the electrode structure is formed on the glass envelope. Since the structure is independent from the light-emitting structure mainly composed of a vessel, there is no need to worry about mechanical strength for electrode formation.

  The electrode pair provided in the electrode structure is provided with an electrode pair pattern extending on both sides of a gap serving as a discharge gap on an insulating substrate having ultraviolet resistance. When the light emitting structure is constituted by a glass thin tube, the light emitting structure and the electrode structure are arranged so that the longitudinal direction of the light emitting tube is in a direction crossing the gap between the electrode pairs. As the insulating substrate for supporting the electrode pair, it is desirable to select and use glass, ceramic, or ultraviolet resistant resin. Further, vacuum ultraviolet rays have a strong oxidation function, and emission to the back side is not preferable because it decomposes a resin or the like of an organic material used as a part of the light source device. In order to prevent leakage of vacuum ultraviolet rays to the back side, it is preferable to provide an ultraviolet cut layer between the light emitting structure and the electrode structure. An ultraviolet light-impermeable film made of magnesium oxide (MgO) powder or the like may be formed on the inner surface of the bottom of the arc tube to form an ultraviolet cut layer.

  When an alternating drive voltage such as a sine waveform or ramp waveform is applied between a pair of long electrodes, the first trigger discharge that occurs between the adjacent electrodes of the electrode as the voltage rises becomes a seed, and then the length of the gradual electrode is increased. As the discharge expands in the direction, efficient ultraviolet light emission over the entire length of the light emitting portion can be obtained.

  More specifically, the first feature of the present invention is that a light emitting structure mainly composed of a tubular glass envelope made of an ultraviolet transmitting glass having a thickness of 100 μm or less, in which a discharge gas is enclosed, and ultraviolet resistance. An electrode structure in which at least one pair of discharge electrodes extending on both sides of a gap constituting a discharge gap is disposed on an insulating substrate, and the light emitting structure is placed on the electrode structure on the tubular glass envelope Are arranged so as to overlap each other in the direction across the gap between the electrode pairs.

  Further, the second feature of the present invention is that the ultraviolet light emitting part mainly composed of a panel-shaped glass envelope in which a discharge gas is sealed between a front side ultraviolet transmissive glass sheet having a thickness of 100 μm or less and a back side glass sheet, An electrode substrate on which an at least one pair of electrodes extending on both sides of a gap serving as a discharge gap is disposed on an insulating substrate having ultraviolet resistance, and on the electrode substrate, a rear side glass of the panel-shaped glass envelope The panel-like glass envelopes are arranged so that the sheets face each other and the internal gas discharge space crosses the gap between the electrode pairs.

  As the glass to be the vacuum ultraviolet ray emitting surface, a borosilicate ultraviolet ray transmitting glass which is drawn or floated to have a thickness of 100 μm or less, preferably 70 μm to 50 μm as described above is preferably used. On the other hand, in the ultraviolet light emitting device having the thin tube structure according to the first feature, the major axis dimension of the thin tube cross section is 5 mm or less, preferably about 2 mm, and the glass thickness is 50 μm or more, preferably about 70 μm, from the viewpoint of maintaining the strength of the thin tube. Is appropriate. In the case of a thin tube configuration, the length of the arc tube is appropriately determined with a size of several centimeters or more depending on the required size of the light source.

  Further, according to the present invention, a flexible ultraviolet surface is obtained by superimposing a light emitting structure in which a plurality of ultraviolet light emitting tubes having a glass thin tube structure are arranged in parallel and an electrode structure having a common electrode pair on each light emitting tube. A light source device can be constructed. A multiband surface light source device may be configured by combining and arranging a plurality of arc tubes having different emission wavelengths. Alternatively, a broadband ultraviolet surface light source device that emits vacuum ultraviolet light and fluorescent light emitting ultraviolet light having a wavelength different from that of a light emitting tube provided with an ultraviolet-excited phosphor layer in a glass thin tube may be configured.

  Furthermore, according to the third feature of the present invention, a tubular base material made of a borosilicate-based ultraviolet transmissive glass having a transmittance of 80% or more with respect to an ultraviolet ray having a wavelength of 250 nm at a thickness of 1 mm is formed with a thickness of 100 to 50 μm. The tube is redrawn into a thin tube having a flat elliptical cross section with a major axis dimension of 5 mm or less, and a discharge gas that radiates ultraviolet rays is sealed in the thin tube to produce a light tube, and the light tube is sandwiched between gaps forming a discharge gap. A method of manufacturing an ultraviolet light source device is provided, which includes a step of placing the electrode assembly on an electrode assembly including at least a pair of discharge electrodes extending on both sides.

  According to the present invention, a thin tube envelope (light emitting tube) or panel envelope (light emitting panel) of ultraviolet light transmitting glass, which is the main component of the light emitting structure, does not have an electrode by itself, and is thin with a thickness of 100 μm or less. Even a glass envelope can maintain sufficient mechanical strength. In addition, the light emitting structure and the electrode structure are configured independently, and the discharge gap length is automatically set just by placing the glass envelope of the light emitting structure in a direction crossing the electrode gap that forms a pair of electrode structures. Therefore, it is possible to provide a vacuum ultraviolet light emitting device that is inexpensive and highly efficient as a whole, as well as being easily assembled and replaced / repaired due to breakage or deterioration of the light emitting portion. Borosilicate UV-transmitting glass constituting the glass envelope is available at a much lower price than quartz glass and is easy to process.

  In addition, a large-area, high-output vacuum ultraviolet plane light source can be easily constructed by arranging a plurality of ultraviolet arc tubes or configuring a panel envelope, so it can be sterilized as a mercury-less deep ultraviolet light source. -The range of applications such as sterilization and exposure can be greatly expanded.

It is the longitudinal cross-sectional view which shows the basic composition of the ultraviolet light source device by this invention as Embodiment 1, and a cross-sectional view. It is a diagram which shows the transmittance | permeability characteristic of the conventional borosilicate type glass (Pyrex: brand name). It is a diagram which shows the transmittance | permeability characteristic of a new borosilicate type | system | group ultraviolet transmission glass. FIG. 3 is a diagram showing an emission spectrum in the ultraviolet light source device of the first embodiment. It is the typical perspective view which shows the structure of the arc tube array type ultraviolet surface light source as Embodiment 2 by this invention, and typical sectional drawing of a modification. It is the top view and longitudinal and cross-sectional view which show the structure of the flat panel type ultraviolet surface light source as Embodiment 3 by this invention.

(Embodiment 1)
1A and 1B are a longitudinal sectional view and a transverse sectional view showing a basic configuration of an ultraviolet light source device using gas discharge according to the present invention as a first embodiment. The ultraviolet light source device of the present invention comprises a light emitting structure 10 and an electrode structure 20 each having an independent part configuration.

  The light-emitting structure 10 is mainly composed of a light-emitting tube 12 composed of a thin tube 11 made of UV-transmitting glass sealed with a discharge gas in which neon (Ne) and xenon (Xe) are mixed and hermetically sealed at both ends. The arc tube 12 is disposed on the ultraviolet cut film 13 in an adhesive state that can be detached by an adhesive 17 such as a silicone resin having good thermal conductivity (FIG. 1B). As a feature of the present invention, the light emitting structure 10 is mainly an elongated glass tube having no electrode inside or outside the tube. The discharge gas is not limited to Ne + Xe gas, but various gases that generate vacuum ultraviolet rays by discharge, such as rare gases such as Xe, Ar, and Kr, mixed gases with nitrogen and neon, and fluorides such as KrF. Can be used.

The glass thin tube 11 is a pipe-shaped base material of transparent borosilicate ultraviolet transmitting glass mainly composed of silicon oxide (SiO ₂ ) and boron oxide (B ₂ O ₃ ) and added with a small amount of fluorine, as shown in FIG. ) Is formed by redrawing (drawing) so as to form a thin tube having a flat elliptical cross-sectional shape with a major axis of 2 mm and a minor axis of 1 mm, as shown in the transverse sectional view of FIG.

  In the fluorine-containing borosilicate ultraviolet transmissive glass proposed in Patent Document 3 referred to above, even when the thickness is 1 mm, the transmittance of about 50% with respect to the ultraviolet light having a wavelength of 200 nm is seen. A transmittance of 80% or more can be obtained for ultraviolet rays having a wavelength of 250 nm. From the relationship between the transmittance curve at a thickness of 1 mm of Pyrex (registered trademark), which is a typical borosilicate glass, and the transmittance curve when the thickness of the glass is reduced to 70 μm, the present inventors described later. Thus, the ultraviolet transmittance was estimated when the thickness of the borosilicate ultraviolet transparent glass was reduced to 70 μm. As a result, when the wall thickness is 70 μm, a transmittance of 80% or more is obtained at a wavelength of 150 nm, and it is certain that a transmittance of 70% or more, which is a practical standard, will be obtained at a wall thickness of 100 μm or less. did.

  That is, the transmittance of a conventional representative borosilicate glass (Pyrex) at a thickness of 1 mm has a hyperbolic characteristic as shown in the characteristic curve (B) of FIG. Further, the transmittance of this glass at a thickness of 0.07 mm (70 μm) has a hyperbolic characteristic similar to the characteristic curve (A) of FIG. 2, and is about 60 nm shorter than the characteristic curve (A) when the thickness is 1 mm. It can be seen that a similar characteristic shifted to is exhibited. However, even if the thickness of this normal borosilicate glass is reduced to 70 μm, the transmittance is only 20% or less for deep ultraviolet rays in the vacuum ultraviolet region with a wavelength of 200 nm or less, and it cannot be used as an envelope of a light source device. .

  Here, the present inventors tried to verify the following hypothesis by paying attention to the similar shift form of the transmittance characteristic with respect to the change in thickness of the borosilicate glass shown in FIG.

  The ultraviolet transmissive glass disclosed in Patent Document 3 shows only the transmittance of a wavelength of 200 nm or more, but the change in the characteristic curve is the transmittance characteristic curve of the conventional typical borosilicate glass shown in FIG. It turns out that it is very similar to the degree of change. Here, assuming that the characteristic curve (B) of FIG. 2 is substantially a hyperbola, this is approximated and the transmittance F is expressed by the following hyperbolic function formula (1).

_{F = [tanh (XX 0)} (m × 10) -3] × Y 0/2 ······ (1)
Here, X is the wavelength, X ₀ is the maximum wavelength of transmittance ₀ , Y ₀ is the maximum transmittance where the transmission wavelength is long, and m is the slope of the substantially linear portion of the center of the transmittance curve.

  Thus, when the transmittance in the wavelength region of 200 nm or less of the 1 mm-thick ultraviolet transmissive glass disclosed in FIG. 3 of Patent Document 3 is approximated and drawn by the above hyperbolic function equation, the characteristic curve (D) of FIG. 3 is obtained. become. Therefore, when this is shifted by 60 nm to the short wavelength side in accordance with the change in transmittance due to the change in the thickness of the conventional borosilicate glass (from 1 mm to 0.07 mm), the curve (C) in FIG. It can be seen that a transmittance of 80% or more can be obtained at 150 nm.

  Based on the above estimation, the present inventors obtain a tubular base material of borosilicate ultraviolet transmissive glass, redraw and produce the gas-containing arc tube 12 having the length of 8 cm as described above, and the ultraviolet cut film 13. The arc tube structure 10 was constructed by adhering to the adhesive 17 (FIG. 1B). In the arc tube 12, a mixed gas in which 10% xenon (Xe) was added to neon (Ne) was sealed at a total pressure of 0.7 atm. A thin multilayer polyester sheet sold under the trade name “Scotch Tint (registered trademark)” can be used for the ultraviolet cut film 13 that prevents the release of vacuum ultraviolet rays to the back side and also serves as a support substrate.

  On the other hand, in the configuration of FIG. 1, an electrode structure 20 constituting a part independent of the light emitting structure 10 is, for example, a gap dimension Dg on an insulating substrate 21 made of polyimide resin such as Kapton tape (registered trademark). And a pair of elongated electrodes 23X and 24Y arranged with a gap G therebetween. For convenience of explanation, one electrode 23X is referred to as an X electrode, and the other electrode 24Y is referred to as a Y electrode. Kapton tape is suitable because it has sufficient ultraviolet light resistance, but a polycarbonate hard substrate may be used depending on the application.

  In the state where the light emitting structure 10 is placed on the electrode structure 20, adjacent adjacent ends of the pair of long electrodes constitute trigger electrode portions 23 a and 24 a, and correspond to the gap dimension Dg of the gap portion G. A trigger discharge portion 15 is formed in the gas space inside the arc tube 12. Further, the extension portions extending in the direction away from the trigger electrode portions 23a and 24a on both sides constitute main electrode portions 23b and 24b, and the corresponding gas space 16 of the main electrode portions 23b and 24b becomes the main gas discharge portion.

  The X electrode 23X and the Y electrode 24Y may be a metal conductor foil such as a copper foil or an aluminum foil attached on the insulating substrate 21 having an ultraviolet resistance, or a conductive film directly formed by a vapor deposition method or a printing method is patterned. May be configured.

  The light emitting structure 10 is placed on the electrode structure 20, whereby the gas discharge light emitting device of the present invention is completed. The elongated arc tube 12 can be operated only by being placed in a direction across (crossing) the gap G along the X and Y electrodes 23X and 24Y in the electrode structure 20.

  Strict alignment is not required between the light emitting structure 10 and the electrode structure 20, but an adhesive means or a mechanical clamp means (not shown) is appropriately provided in order to keep the mounting state stable. A range obtained by combining the gap dimension Dg and the effective lengths of the X and Y electrodes 23X and 24Y is an effective light emitting region.

  In the ultraviolet light source device which is also an external electrode type gas discharge light emitting device shown in FIG. 1, the present inventors have confirmed the inside of the arc tube 12 in order to confirm the emission of 172 nm vacuum ultraviolet rays from Xe contained in the sealed gas. An ultraviolet phosphor layer 14 that emits ultraviolet light having a central wavelength of 258 nm was previously formed on the bottom surface. When driving, if the light emission in the direction of the arrow 22 (FIG. 1B) from the phosphor layer 14 that emits light by being excited by the vacuum ultraviolet light accompanying the gas discharge can be observed, the vacuum ultraviolet light is generated inside the arc tube. Is certain. At the same time, it is possible to confirm the emission of vacuum ultraviolet light at 172 nm by observing the emission wavelength spectrum including the vacuum ultraviolet region.

  The driving of the gas discharge light emitting device shown in FIG. 1, that is, the ultraviolet light source device, is the same as the driving technique disclosed in the above-mentioned prior patent document 2, and is between the paired X electrode 23X and Y electrode 24Y. This is done by connecting an inverter power supply to and applying a sine wave voltage with a frequency of 40 kHz. When the sine wave voltage exceeds the discharge start voltage between the trigger electrode parts 23a and 24a, trigger discharge occurs in the trigger discharge part 15, and as the applied sine wave voltage rises, the discharge is accompanied by the accumulation of wall charges and the main electrode. The parts 23b and 24b are expanded in the longitudinal direction. This discharge operation is repeated every time the polarity of the sine wave voltage is reversed.

  FIG. 4 is a diagram showing an emission spectrum when the gas discharge device of Embodiment 1 is driven in comparison with a conventional device. The spectrum shown by the curve (F) shows the light emission characteristics of a device in which an ultraviolet phosphor layer emitting light at a central wavelength of 258 nm is formed in a thin tube having a thickness of 70 μm of conventional borosilicate glass (registered trademark: Pyrex). The other curve (E) shows the light emission characteristics of the device of Embodiment 1 in which an ultraviolet phosphor layer that also emits light at a central wavelength of 258 nm is formed in a thin tube having a thickness of 70 μm of a newly obtained borosilicate ultraviolet transmission glass. Show.

  FIG. 4 shows that the arc tube using the conventional borosilicate glass can emit light in the vacuum ultraviolet region, but cannot be used as a light source. On the other hand, in the arc tube of the present invention using ultraviolet transmissive glass, as is clear from the curve (E), the vacuum ultraviolet ray having a wavelength of 172 nm emitted by Xe during discharge is about half of the emission intensity of 258 nm from the phosphor layer 14. It can be seen that it is discharged outside the tube with the intensity of.

  That is, the transmittance in the vacuum ultraviolet region estimated by applying the relationship between the thickness and transmittance of a general borosilicate glass to the ultraviolet transmissive glass can be demonstrated in FIG. Thus, it is possible to realize a vacuum ultraviolet light source that has been impossible except for quartz glass with an inexpensive borosilicate glass envelope. According to the experiments by the present inventors, the thickness of 200 μm is the limit for transmitting deep ultraviolet rays of 200 nm or less with a practical transmittance of 80% or more even with ultraviolet transmissive glass, and the transmittance is 80%. The practical limit wall is observed to have a wavelength of 194 nm at a thickness of 200 μm and a wavelength of 180 nm at a thickness of 100 μm.

  The transmittance in the deep ultraviolet region is better as the glass thickness is thinner. However, manufacturing a gas discharge device with a glass envelope as thin as 70 μm is the idea of a conventional light source device based on electrode integration. From this point of view, it is difficult to imagine from the viewpoint of mechanical strength. This is the reason why a light-emitting structure with a tube structure that is easy to make thin and thin is adopted, and the light-emitting structure and the electrode structure are assembled independently. There is a unique feature of the present invention configured as a body.

(Embodiment 2: arc tube array type vacuum ultraviolet surface light source device)
FIG. 5 (a) is a schematic perspective view of an arc tube array type vacuum ultraviolet surface light source device as Embodiment 2 of the present invention. The surface light source device 4 having an array configuration is formed by arranging a plurality of ultraviolet ray transmitting glass arc tubes 12 shown in FIG. 1 in parallel in a direction crossing the longitudinal direction.

  A plurality of arc tubes 12 constituting the arc tube array structure 1 in the arc tube array form are provided on a thin (several tens of μm) ultraviolet cut film 13 having heat resistance, which is shown in FIG. In addition, as described above, it is disposed in an adhesive state that can be detached by the adhesive 17 having good thermal conductivity such as a silicone resin. A gap having the same width dimension or a partially different width dimension is provided between the adjacent arc tubes 12 in order to provide flexibility to the surface light source device 4.

  On the other hand, under the arc tube array structure 1, an electrode structure 20 comprising, for example, a flexible insulating substrate 21 made of polyimide resin and electrode pairs 23X and 24Y formed thereon is adhered (non-adhered). Is provided.

  An electrode pair of the electrode structure 20 is opposed to the back of the bottom of each arc tube 12 constituting the arc tube array structure 1 and has a belt-like X electrode 23X and Y electrode 24Y extending on both sides with a common gap G interposed therebetween. It consists of.

  That is, the X electrode 23X and the Y electrode 24Y have a common electrode pattern that extends in a direction intersecting with the longitudinal direction of each arc tube 12 as a whole, but the individual arc tubes 10 are initially in the arc tube. It has a configuration of long electrode pairs that extend symmetrically on both sides in the longitudinal direction with a gap G of about 0.1 to 10 mm that generates discharge. The length of the X electrode 23X and the Y electrode 24Y in the longitudinal direction of the arc tube is 5 to 10 times the width of the gap G or more.

  Incidentally, the arc tube 10 is composed of 8 cm long glass capillaries having a flat elliptical cross section with a major axis of 2 mm and a minor axis of 1 mm, and 20 arcuate tubes are arranged at intervals of 1 mm to form an arc tube array structure as shown in FIG. When the body 1 is configured, the X electrode 23X and the Y electrode 24Y are provided on both sides of the gap G having a gap width of 3 mm in a pattern extending in a direction intersecting with each arc tube 10 with a width of 38.5 mm. .

As a result, the back side of the light emitting surface of 8 × 6 = 48 cm ² is entirely covered with the electrode surface except for a gap of 0.3 × 6 = 1.8 cm ² corresponding to the gap width of the gap G. Become. The electrode coverage with respect to the light emitting area corresponds to 96%.

  The X electrode 23X and the Y electrode 24Y may be directly formed by printing a conductive ink such as silver paste on the insulating substrate 21 having ultraviolet resistance, or a preliminarily formed metal conductor foil such as copper or aluminum. It may be formed by adhesion or adhesion. Of course, an electrode pair can be formed by patterning a conductor layer formed on the insulating substrate 21.

  In driving, an inverter power supply is connected between the X electrode 23X and the Y electrode 24Y, and an alternating drive voltage having a rising slope such as a sine wave or a ramp wave is applied, so that the vacuum ultraviolet rays can be efficiently discharged from the arc tube array surface. Can be emitted. In this case, it is possible to adjust the emission intensity of the ultraviolet light by intermittently applying the alternating voltage at a predetermined burst cycle and adjusting the duty ratio between the application time and the non-application time.

  FIG. 5B is a cross-sectional view schematically showing a modification of the arc tube array type surface light source device. In this arc tube array structure, glass rods 120 as reinforcing members having a height higher than that of the arc tube 12 are arranged alternately with the arc tubes including both sides of the array structure, and the light emitting surface of the arc tube 12 Is located below the top surface of the glass rod 120. With this configuration, even when a foreign substance or the like touches the ultraviolet irradiation surface, it is possible to avoid a risk that an external force is directly applied to the thin glass capillary tube. Of course, the reinforcing member is not limited to a glass rod, and an ultraviolet resistant resin or the like can be appropriately selected and used. The cross-sectional shape of the reinforcing member can be appropriately selected such as an ellipse or a rectangle in addition to a circle. Further, the reinforcing members 120 are not limited to the alternate arrangement for each arc tube except for both sides, and may be arranged every plural number. Further, the entire irradiation surface may be covered with an ultraviolet ray transmitting sheet (not shown) so as to be supported by the top surface of the reinforcing member.

(Embodiment 3: Flat panel vacuum ultraviolet light source device)
The ultraviolet light source device of the present invention may have a panel configuration in addition to the arc tube array configuration in which a plurality of gas discharge arc tubes 10 are arranged as described above. 6A, 6B, and 6C are a perspective plan view and vertical and horizontal sectional views for explaining the surface light source device 40 having such a panel configuration.

  The configuration of the light source device 40 is not substantially different from the configuration in which the arc tube array structure 1 shown in FIG. 5 is replaced with one panel envelope 100. In FIG. 6, the panel envelope 100 includes a front substrate 101 and a rear substrate 102, and a sealed gas filled space 103 is formed between them. The gas space 103 is partitioned into a plurality of striped discharge channels by a glass rod 104 having a spacer function, or ribs (not shown) previously formed in the same arrangement pattern on the back substrate 102, and the periphery is also similar to the glass rod. Is sealed through. The glass rod 104 is divided into both sides with a gap corresponding to the trigger discharge gap G at the center, and an exhaust pipe 105 is provided in communication with the common space of the divided portions.

  The front substrate 101 is made of a thin borosilicate ultraviolet transmissive glass having a thickness of 100 μm or less, like the glass constituting the arc tube of the first embodiment. The back substrate 102 may also be made of borosilicate microsheet glass of the same material, but it is preferably made of ultraviolet cut glass because it does not require ultraviolet light transmission performance unlike the front substrate. The glass rod having a spacer function serves to reinforce the mechanical strength of the thin front substrate while defining the substrate spacing in the discharge space.

  On the back side of the back substrate 102, a support substrate 108 made of glass or ceramic is attached with an adhesive having good thermal conductivity so as to sandwich the electrode pairs 106X and 106Y. The electrode pairs 106X and 106Y are preferably formed in advance on the support substrate 108. The support substrate 108 serves not only to support the panel-shaped glass envelope composed of the thin front substrate 101 and the back substrate 102, but also serves as an electrode substrate and a heat sink. Further, as in the case of the first embodiment, an ultraviolet cut film for preventing the emission of vacuum ultraviolet rays to the thin back side (not shown) may be interposed between the back substrate 102 and the electrode support substrate 108 of the panel envelope.

  The ultraviolet surface light source device 40 having the panel configuration can be driven in the same manner as the surface light source device 10 having the arc tube array configuration described above. The electrode pairs 106X and 106Y do not necessarily have the common solid pattern as shown in the figure, and correspond to the striped gas discharge channels partitioned by the spacers 104 in the respective longitudinal directions. It may be formed as an extended stripe-shaped electrode pattern and commonly connected at both ends.

(Other variations)
Vacuum ultraviolet radiation is emitted at a wavelength specific to the enclosed discharge gas, and its intensity depends on the partial pressure. A preferable gas for obtaining vacuum ultraviolet rays in the deep ultraviolet region is xenon (Xe), and xenon emits vacuum ultraviolet rays having wavelengths of 147 nm and 172 nm. The discharge gas mixed with krypton (Kr) emits vacuum ultraviolet rays having a wavelength of 153 nm. In addition, when a rare gas such as argon gas (Ar) or the like, halogen such as chlorine (Cl), fluorine (F), or a synthetic gas thereof is filled and discharged, vacuum ultraviolet rays specific to each gas are generated. be able to. By the way, it is possible to emit vacuum ultraviolet rays of 126 nm for Ar ₂ , 146 nm for Kr ₂ , 222 nm for KrCl, and 308 nm for XeCl. Conventionally, such vacuum ultraviolet rays are difficult to be taken out of the envelope with an inexpensive structure, and have been used only for exciting the phosphor layer formed inside the envelope. In the present invention, this vacuum ultraviolet ray can be used by taking it out of the envelope with an inexpensive configuration, and at the same time, it can also be used for excitation of a phosphor.

That is, as described above, the arc tube 12 (FIGS. 1 and 5) of the present invention or the inner bottom surface of the light emitting panel 100 (FIG. 6) has a UV-C wavelength region as disclosed in Patent Document 1. By adopting the configuration in which the ultraviolet phosphor layer 14 is formed, for example, vacuum ultraviolet rays having a wavelength of 172 nm from xenon and ultraviolet rays having a wavelength of 258 nm from the phosphor layer can be emitted. Here, vacuum ultraviolet rays have the property of decomposing oxygen and generating ozone (O ₃ ) when released into the air. Therefore, for example, if such a multi-wavelength light source device in the deep ultraviolet region is arranged in the sterilization chamber to irradiate the object to be sterilized, the sterilization effect by the 258 nm ultraviolet light that goes straight and the object to be sterilized together with air It is possible to use the bactericidal effect of ozone that wraps around behind.

  In the case of constructing an arc tube array type surface light source, in addition to an arc tube dedicated for vacuum ultraviolet rays, an ultraviolet or visible arc tube using the phosphor layer 14 is combined and arranged in an arbitrary number ratio. Therefore, it is possible to design the distribution of light emission energy according to the application field. In this case, for the light emitting tubes having different light emission wavelengths, the electrode pair pattern of the corresponding electrode assembly is extended in the longitudinal direction of the light emitting tube, and the light emission wavelength is selectively driven on the insulating substrate as appropriate. Can be done. Alternatively, electrode pairs for each arc tube can be derived individually or as a plurality of groups, and thinning driving or light emitting area selection driving can be performed.

In the case where a multi-wavelength light source device including the visible and ultraviolet regions is formed using the thin ultraviolet transmissive glass as described above, the emission wavelength is also obtained from the arc tube provided with the visible or ultraviolet phosphor layer 14. However, naturally, vacuum ultraviolet rays are also emitted at the same time. However, it is desirable to prevent the emission of vacuum ultraviolet rays from the arc tube using a phosphor in a configuration in which the irradiation is selectively switched between vacuum ultraviolet emission and other visible and ultraviolet rays. In this case, it is preferable to provide a vacuum ultraviolet ray cut layer having a filter function transparent to the used wavelength on the inner surface on the front side facing the bottom side of the arc tube provided with a visible or ultraviolet phosphor layer. As an example of the inner surface cut layer against vacuum ultraviolet rays, a film of magnesium oxide (MgO), aluminum oxide (Al ₂ O ₃ ), or silicon dioxide (SiO ₂ ) can be used.

  Further, in place of or in addition to the ultraviolet cut film 13 for cutting off the emission of ultraviolet rays to the back side, a thickness of 1 μm having a function of absorbing or reflecting ultraviolet rays on the inner surface of the bottom facing the irradiation surface of the arc tube 12 or the light emitting panel 100 It is also possible to provide the following ultraviolet opaque layer. As an example of the ultraviolet-opaque layer, the phosphor layer 14 provided on the inner surface of the bottom of the arc tube 12 may be used, or an ultraviolet-ray-impermeable layer made of magnesium oxide (MgO) powder or the like instead of the phosphor layer 14 may be used. A transmission layer may be provided. The MgO layer can prevent the leakage of vacuum ultraviolet rays to the back side of the arc tube, and can obtain the effect of reducing the discharge voltage and the effect of protecting the glass inner surface from ion bombardment. In order to form such an ultraviolet opaque layer of MgO on the inner bottom surface facing the light emitting surface side of the glass capillary 11, for example, the technique described in JP 2013-134950 A is reversed with the front side and the back side reversed. Can be used.

  As is apparent from the above description, the present invention is a light-emitting assembly mainly composed of a gas-filled envelope that does not have an electrode itself, in which the light-emitting surface side is made of a thin ultraviolet-transmitting glass having a thickness of 100 μm or less. And an electrode assembly for applying a driving voltage to the gas-filled envelope are configured as independent parts, and they are overlapped to form a vacuum ultraviolet light emitting device. Although the invention of such a vacuum ultraviolet light source device was triggered by the appearance of a new borosilicate ultraviolet transparent glass, it exceeded the prediction of those skilled in the art.

  In the ultraviolet light emitting device of the present invention, it is possible to easily replace at a low cost when the arc tube is broken or deteriorated by preparing a simple arc tube without electrodes as a component. Further, by using the present invention, it is possible to efficiently obtain planar vacuum ultraviolet light emission that is mercury-free and has high emission intensity per area.

10: Light-emitting structure 11: Glass capillary 12: Light-emitting tube 13: Ultraviolet cut film 14: Phosphor layer 20: Electrode structure 21: Insulating substrate 23: X electrode 24: Y electrode 1: Arc tube array structure 100: Panel Envelope 120: Glass rod

Claims (18)

  A light-emitting structure mainly composed of a glass envelope in which an irradiation surface side is made of an ultraviolet transmitting glass having a thickness of 100 μm or less and in which a discharge gas that emits ultraviolet rays is enclosed, and a gap that forms a discharge gap on an insulating substrate An electrode structure in which at least one pair of discharge electrodes extending on both sides of the electrode structure is disposed, and the light emitting structure is disposed on the electrode structure in a direction in which a discharge gas sealed space of the light emitting structure crosses the gap. An ultraviolet light source device characterized by being arranged.   2. The ultraviolet light source device according to claim 1, wherein the glass envelope is made of fluorine-containing borosilicate glass having a transmittance of 80% or more with respect to ultraviolet light having a wavelength of 250 nm at a thickness of 1 mm.   3. The ultraviolet light source device according to claim 1, wherein the discharge gas is composed of a rare gas and a halogen single gas or a synthesis gas, and emits vacuum ultraviolet rays by discharge.   3. The ultraviolet light source device according to claim 1, wherein the discharge gas is a mixed gas of neon and xenon and emits a vacuum ultraviolet ray emitted by xenon by discharge.   5. The ultraviolet light source device according to claim 1, wherein a thickness of the glass envelope on an irradiation surface side is in a range of 50 μm to 100 μm.   6. The light emitting structure according to any one of claims 1, 2, 3, 4 and 5, wherein the light emitting structure is mainly composed of a light emitting tube made of an envelope in the form of a thin tube made of an ultraviolet light transmitting glass having a thickness of 50 μm to 100 μm. 2. An ultraviolet light source device according to item 1.   The light emitting structure has a structure of an arc tube array in which a plurality of arc tubes are arranged in parallel, and the electrode structure has an electrode pair common to the plurality of arc tubes. The ultraviolet light source device according to claim 6.   The glass envelope has a flat panel structure comprising a front side substrate made of ultraviolet transmissive glass having a thickness of 50 to 100 μm and a back side substrate disposed in an airtight manner with a support spacer interposed therebetween. The ultraviolet light source device according to any one of claims 1, 2, 3, 4, and 5.   The ultraviolet light source device according to claim 1, wherein a back side of the glass envelope is supported by an ultraviolet cut layer.   The ultraviolet light source device according to any one of claims 1 to 8, wherein an ultraviolet opaque layer is provided on an inner bottom surface of the glass envelope.   The ultraviolet light source device according to claim 10, wherein the ultraviolet opaque layer is a layer made of magnesium oxide powder and having a thickness of 1 μm or less.   At least one arc tube composed of a glass tube having a thickness of 200 μm or less and made of borosilicate glass having a transmittance of 80% or more for ultraviolet light having a wavelength of 250 nm at a thickness of 1 mm, and having a discharge gas emitting ultraviolet light enclosed therein. And an electrode structure in which at least one pair of discharge electrodes extending on both sides of the gap constituting the discharge gap is disposed on one surface of the insulating substrate, and the light emitting structure is disposed on the electrode structure. An ultraviolet light source device characterized in that a body is placed in a direction in which the arc tube crosses the gap.   The light emitting structure has an arc tube array configuration in which a plurality of arc tubes are arranged in parallel, and the electrode structure has a common discharge electrode pair for the plurality of arc tubes. The ultraviolet light source device according to claim 12.   A tubular base material made of a borosilicate ultraviolet transparent glass containing fluorine having a transmittance of 80% or more with respect to an ultraviolet ray having a wavelength of 250 nm at a thickness of 1 mm has a thickness of 100 to 50 μm and a major axis dimension of 5 mm or less. A glass thin tube having a flat elliptical cross section is redrawn, and a discharge gas that emits ultraviolet rays is sealed in the glass thin tube to produce a light emitting tube, and the light emitting tube extends to both sides with a gap constituting a discharge gap therebetween. A method of manufacturing an ultraviolet light source device, including a step of placing the arc tube in a direction crossing the gap on an electrode structure including a pair of discharge electrodes.   15. The method according to claim 14, further comprising the step of forming an ultraviolet opaque layer made of magnesium oxide powder on the inner surface of the bottom of the glass capillary before the discharge gas is sealed in the glass capillary. Manufacturing method of ultraviolet light source apparatus.   A light emitting structure mainly comprising a glass envelope in which a discharge gas that emits ultraviolet rays is enclosed, and at least a pair of discharge electrodes extending on both sides of the gap constituting the discharge gap are arranged on the insulating substrate. A light source device using a gas discharge having a structure in which the light emitting structure is disposed on the electrode structure in a direction in which a discharge gas sealed space of the light emitting structure crosses the gap. An ultraviolet light source device for vacuum ultraviolet light emission, characterized in that the envelope is composed of a glass capillary having a thickness of 100 μm or less made of borosilicate glass having a transmittance of 80% or more with respect to ultraviolet rays having a wavelength of 250 nm at a thickness of 1 mm .   17. The ultraviolet light source device according to claim 16, wherein an ultraviolet opaque layer made of magnesium oxide is formed on the inner surface of the bottom portion of the glass capillary facing the electrode structure.   The light emitting structure has an arc tube array configuration in which a plurality of arc tubes made of the glass thin tubes are arranged in parallel with a gap member having a dimension higher than that of the arc tube interposed between adjacent arc tubes, and The ultraviolet light source device according to claim 16 or 17, wherein the electrode structure has a common discharge electrode pair for the plurality of arc tubes.

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