JP6955798B2 - Ultraviolet irradiation device - Google Patents

Description

The present invention relates to an ultraviolet light source device having a self-condensing function that enables concentrated irradiation of a strong ultraviolet light beam from a light source to an irradiation target without using a condensing mirror or a condensing lens. The present invention relates to an ultraviolet irradiation device having a self-condensing function using a flexible surface light source composed of an array of luminescent gas discharge tubes.

Conventionally, ultraviolet rays have been widely applied in fields such as industrial use, medical use, sterilization and sterilization, but the reality is that there are no practical light source devices other than high-pressure mercury lamps and excimer discharge lamps. be. Ultraviolet light emitting LEDs, which are attracting attention as a mercury-less structure, are still under development and have not been obtained with sufficient light emission intensity. For example, as disclosed in Patent Document 1, luminous flux from a plurality of LED light emitting elements is emitted. A technique is known in which light is collected by a curved reflection mirror to increase the irradiation intensity. Further, Patent Document 2 also proposes a flat light source device for ultraviolet light emission using a gas discharge tube having an external electrode configuration, but it is also desired to improve the light emission intensity.

Japanese Patent Application Laid-Open No. 2012-199055 Japanese Patent Application Laid-Open No. 2011-040271

As described above, in the conventional light source device using LEDs, the entire device becomes large due to the curved reflection mirror and the range of use is limited, and in the conventional flat light source using a gas discharge tube, the electrode configuration is complicated. In addition, it has not yet reached the practical level in terms of luminous efficiency and emission output.

Therefore, the present invention is intended to provide a mercury-less light source device capable of obtaining high-intensity irradiation light, and in particular, to provide a light source device having a self-condensing function without using a reflection mirror or a condensing lens. Is the purpose.

The present invention is based on a new external electrode type ultraviolet emitting gas discharge tube in which a discharge is generated between a pair of long electrodes provided along the longitudinal direction of an elongated glass tube. This new ultraviolet emitting gas discharge tube has a different electrode structure and discharge type from the light emitting tube used for the conventional flat light source, and the luminous efficiency is greatly improved. Further, when a plurality of light emitting tubes are arranged on a common electrode pair to form a surface light source, it is possible to cover 80% or more of the back side of the light emitting tubes with a reflective electrode material such as aluminum foil. Therefore, a higher light collecting function can be obtained.

Thus, in the present invention, a plurality of ultraviolet emitting gas discharge tubes having a new configuration as described above are arranged on a curved surface or a bent surface so that the irradiation light flux of each of them converges toward the irradiation target, and the maximum irradiation is performed at the irradiation target position. The main point is to obtain strength. Equally spaced or partially differently spaced gaps are provided between adjacent tubes to allow the light emitting surface to bend. The ultraviolet emitting gas discharge tube is not limited to the one provided with a phosphor layer that emits light in the ultraviolet region, and may be configured to have a mixture of light emitting tubes in the visible region depending on the irradiation application.

More specifically, the ultraviolet irradiation device having a self-condensing function according to the present invention has an electrode structure in which at least one pair of strip-shaped electrode pairs are arranged in parallel on an insulating substrate, and an ultraviolet phosphor layer on the inner bottom surface. The electrode structure comprises a tube array structure in which a plurality of ultraviolet luminescent gas discharge tubes having a discharge gas sealed therein are arranged in parallel on one surface with a minute interval between adjacent tubes. A flexible ultraviolet light emitting structure is formed by combining the tube array structures so that the bottom surface side of the plurality of discharge tubes is located on the discharge tube so as to cross the strip-shaped electrode pair, and the irradiation light beam of each discharge tube is irradiated. It is characterized in that at least a part of the array surface of the discharge tube of the tube array structure is curved or bent so as to converge toward the target.

The array surface of the ultraviolet emitting gas discharge tube may be a composite plane formed so as to sandwich the irradiation target, or may be a cylindrical surface such as a cylinder or a square cylinder. When the array surface of the ultraviolet emitting gas discharge tube is formed in a tubular shape, the array surface may be formed of a glass cylinder or a mesh structure that is transparent to ultraviolet rays.

According to the ultraviolet irradiation device of the present invention, it is possible to realize a self-condensing function with a simple structure without combining optical elements such as a condensing mirror and a condensing lens, as well as achieving mercury-free operation. As a result, it becomes possible to irradiate the target surface with high-intensity ultraviolet rays with a safe and inexpensive configuration, and the industrial practical range such as medical use and sterilization / sterilization use is greatly expanded.

It is explanatory drawing explaining the basic structure of the surface light source device using the ultraviolet light emitting gas discharge tube used for the ultraviolet irradiation apparatus by this invention. It is explanatory drawing which shows the structure of the light emitting surface and the irradiation profile in Embodiment 1 of the ultraviolet irradiation apparatus of this invention. It is a schematic perspective view which shows the use example of the ultraviolet irradiation apparatus by this invention. It is a perspective view which shows the structure of the light emitting surface of the ultraviolet irradiation apparatus of Embodiment 2 of this invention.

Hereinafter, the present invention will be described in detail with reference to the embodiments shown in the drawings. This does not limit the invention.

(Embodiment 1)
FIG. 1 (a) is a cross-sectional view showing a basic configuration of an ultraviolet luminescent gas discharge tube used in the ultraviolet irradiation device according to the first embodiment of the present invention, and FIG. 1 (b) shows a plurality of the ultraviolet luminescent gas discharge tubes arranged. A perspective view showing the basic configuration of the constructed surface light source, FIG. 1C is an explanatory view for explaining the driving principle thereof.

[Ultraviolet emission gas discharge tube]
As shown in FIG. 1 (a), the new ultraviolet emitting gas discharge tube (hereinafter referred to as light emitting tube) 1 is mainly composed of an elongated glass tube 2 having a flat elliptical cross section, and an ultraviolet phosphor layer on the inner bottom surface thereof. 3 is provided, and a discharge gas in which neon and xenone are mixed is sealed inside, and both ends are sealed. The glass tube 2 is a thin tube made of borosilicate glass containing silicon oxide (SiO2) and boron oxide (B2O3) as main components, for example, having a flat elliptical cross section with a major axis of 2 mm and a minor axis of about 1 mm. Sufficient transmittance for ultraviolet rays is realized by limiting it to 300 μm or less.

When a gadrillium-activated phosphor (LaMgAl11O19: Gd) is used for the ultraviolet phosphor layer 3, ultraviolet light emission of 311 nm, which is a wavelength range of the UV-B band effective for industrial and medical purposes, can be obtained. Further, if a praseodymium-activated phosphor (YBO3: Pr or Y2SiO5: Pr) is used, ultraviolet emission of 261 nm or 270 nm in the wavelength range of the UV-C band having a sterilizing and sterilizing effect can be obtained.

[Flexible surface light source device]
As shown in FIG. 1 (b), a plurality of light emitting tubes 1 mainly composed of a glass tube 2 are arranged in parallel in a direction intersecting the longitudinal direction of the tubes, and a surface light source device (light emitting tube array structure) having an array configuration. 10 is made. As is more apparent in relation to the cross-sectional view of FIG. 1A, each light emitting tube 1 constituting the light emitting tube array structure 10 conducts heat like a silicone resin on a heat-resistant thin insulating film 11. It is arranged in a sticky state that can be removed by the pressure-sensitive adhesive 12 having good properties. A gap having the same width or a partially different width is provided between the adjacent light emitting tubes 1 so as to allow the light emitting surface to be curved.

On the other hand, under the light emitting tube array structure 10, for example, an electrode structure 15 composed of a flexible insulating substrate 13 made of a polyimide resin and an electrode pair 14 formed on the flexible insulating substrate 13 is arranged in a non-adhesive state. ing. The electrode pair 14 is composed of a band-shaped X electrode 14X and a Y electrode 14Y that face the back surface of the bottom of each light emitting tube 1 constituting the light emitting tube array structure 10 and spread on both sides with a common electrode slit G interposed therebetween.

That is, the X electrode 14X and the Y electrode 14Y have a common electrode pattern extending in a direction intersecting the longitudinal direction of each light emitting tube 1 as a whole, but for each light emitting tube 1, the initial state in the tube is set. It has a configuration of long electrode pairs extending symmetrically on both sides in the longitudinal direction with an electrode slit G of about 0.1 to 10 mm for generating an electric discharge. The length of the X electrode 14X and the Y electrode 14Y in the tube longitudinal direction is 5 to 10 times or more the width of the electrode slit G.

Incidentally, the light emitting tube 1 is composed of a glass thin tube having a major axis of 2 mm and a minor axis of 1 mm and a length of 5 cm having a flat elliptical cross section, and 20 of these tubes are arranged in parallel at 1 mm intervals to emit light as shown in FIG. 1 (b). When the tube array structure 10 is configured, the X electrode 14X and the Y electrode 14Y are provided on both sides of a 3 mm wide discharge slit G in a pattern extending in a direction intersecting each light emitting tube 1 with a width of 23.5 mm. Be done. As a result, the back side of the light emitting surface of 5 × 6 = 30 cm ² is completely covered with the electrode surface except for the gap of ^{0.3 × 6 = 1.8 cm 2 corresponding to the width of the electrode slit G.} .. The coverage of the electrode with respect to the light emitting area corresponds to 94%.

The X electrode 14X and the Y electrode 14Y may be formed directly by printing a conductive ink such as silver paste on the insulating substrate 13, or by adhering or adhering a preformed metal conductor foil such as copper or aluminum. May be configured.

When the insulating film 11 that supports the light emitting tube 1 in an array is made of a fluorine-based transparent resin such as Teflon (registered trademark), it is preferable to use a material having high light reflectance for the X and Y electrodes 14X and 14Y. In that sense, it is particularly effective to use aluminum foil. In this case, the electrode slit G may become a window that opens downward and ultraviolet light may escape to the back. Therefore, the corresponding portion of the electrode slit G is an insulating material having a photoreaction ratio equivalent to that of the electrode material, for example, light reflection. It is preferable to cover it with tape.

Further, the light emitting tube 1 may be arranged by directly providing an adhesive insulating layer such as a silicone resin on the insulating substrate 13 on which the electrode pair 14 is formed. As a result, the light emitting tube 1 and the electrode pair 14 can slide in a non-adhesive state, so that the tensile force applied to the insulating substrate 13 when the flexible surface light source device is curved can be absorbed.

[Drive principle]
The new type of light emitting tube 1 which is the basic unit of the ultraviolet irradiation device according to the present invention is an external electrode type and is driven by a sinusoidal voltage. That is, as shown in FIG. 1 (c), the inverter power supply 17 is connected so as to apply a sinusoidal voltage to the other Y electrode 14Y with one X electrode 14X of the electrode pair 14 grounded. Trigger discharge occurs when the voltage between the electrodes close to each other in the electrode slit G exceeds the discharge start voltage of the corresponding gas space in the process of increasing the sinusoidal voltage.

Since the discharge start voltage in the vicinity decreases due to the pilot fire effect due to the supply of space charge from this trigger discharge, a new discharge is generated in both ends of the X electrode 14X and the Y electrode 14Y in combination with the increase in the applied sinusoidal voltage. Expand.

On the other hand, as a feature of the external electrode type discharge device, charges (electrons and cations) having a polarity opposite to the polarity of the applied voltage are accumulated as wall charges on the inner wall of the discharged electrode-corresponding part, and this internal electric field is applied to the corresponding part. As a result of canceling the electric field of the external voltage, the discharge once generated will be stopped in sequence. This principle of operation is described in more detail in Japanese Patent Application No. 2015-148622 (Patent No. 6,103,730) filed earlier by the present inventors.

When the polarity of the applied sinusoidal drive voltage is reversed, the internal electric field due to the wall charge is added to the electric field of the externally applied voltage. The expansion and cessation of the discharge as the sinusoidal voltage rises in the opposite direction proceeds in the direction across the electrode pair 14. By repeating this operation, gas discharge and accompanying light emission are performed.

Incidentally, the frequency of the sinusoidal drive voltage is set to 10 KHz to 40 KHz, for example, 25 KHz in relation to the capacity of the gas space as a load and the capacity between the electrodes. Further, the peak voltage is 1000 V or more, which is higher than the discharge start voltage of the gas space corresponding to the electrode slit G, but exceeds the spread length of the discharge on the long electrode pair and the withstand voltage of the electrode slit portion 16. It is desirable to consider the balance between both damage prevention and damage prevention.

By the way, in order to drive the surface light source device consisting of 20 light emitting tubes with a length of 5 cm illustrated above, an inverter circuit that converts a 12 V DC voltage (battery) into a 20 KHz sine wave and a peak of this sine wave. A small inverter power supply including a small transformer that boosts the voltage to 2000V is sufficient.

[Self-condensing function]
By the way, in the surface light source device 10 having a flat light emitting surface shown in FIG. 1, even if the irradiation target is arranged close to the light emitting surface, the irradiation intensity equal to or higher than the light emitting intensity of each light emitting tube 1 cannot be obtained. The present invention is characterized by a configuration having a self-condensing function in which light fluxes of a plurality of light emitting tubes 1 are converged toward an irradiation target by bending a light emitting surface. This takes full advantage of the flexibility of the surface light source device 10 which is a light emitting tube array structure.

FIG. 2 is an explanatory diagram showing a light emitting surface configuration and an irradiation intensity profile of the ultraviolet irradiation device according to the first embodiment. The surface light source 20 composed of an array of a plurality of light emitting tubes 1 as described above is entirely curved as shown in FIG. 2 so as to have a curved light emitting surface. In order to realize this curved surface, as described above, a gap for absorbing the curvature of the insulating film 11 and the electrode substrate 13 is indispensable between the adjacent tubes.

That is, the flexible light source device can be curved until the adjacent light emitting tubes 1 come into contact with each other to absorb the compressive force. In the case of obtaining a curved surface with a small value, the arrangement spacing on both sides is widened as compared with the intermediate portion. Further, since the insulating substrate 13 at the time of bending and the insulating film 11 supporting the light emitting tube arrangement are only in contact with each other in an overlapping state and are not fixed by mechanical fixing means, the tension at the time of bending is both. It will be absorbed by the slip between.

By curving the light emitting surface, the light emitting central axis (hereinafter referred to as the optical axis) 22 of each light emitting tube converges toward the inside of the curved surface. As a result, with respect to the flat light receiving surface 23, as shown in FIG. 2A, it is possible to obtain an irradiation intensity profile 24 having substantially uniform and high intensity corresponding to the curved light emitting surface. Therefore, if a three-dimensional irradiation object 25 is placed instead of the light receiving surface 23, as shown in FIG. 2B, the entire surface of the object 25 can be irradiated with ultraviolet rays substantially evenly with the irradiation intensity profile 26. It will be possible.

(Embodiment 2)
FIG. 3 is a schematic explanatory view showing the second embodiment of the ultraviolet irradiation device having a self-condensing function according to the present invention.

In FIG. 3A, the ultraviolet irradiation device 30 curved in a tunnel shape is arranged so as to cover a part of the traveling path of the automatic conveyor (belt conveyor) 35. The ultraviolet irradiation device 30 has a configuration in which the light emitting surface of an ultraviolet light source device composed of a flexible electrode support and a plurality of light emitting tubes 1 arranged on the flexible electrode support (lower surface side in the figure) is curved inward. The optical axis of the tube 1 has a shape that converges toward the three-dimensional irradiation target object 36 mounted on the conveyor 35.

According to this embodiment, it is possible to provide an irradiation device capable of directly irradiating a three-dimensionally shaped irradiation object 36 mounted on the automatic carrier 35 with ultraviolet rays having a bactericidal effect with a strong intensity. In particular, the ultraviolet irradiation device 30 is automatic because the main light source device is flexible in the direction intersecting the longitudinal direction of the light emitting tube 1 and the width of the light emitting surface can be determined by the number of light emitting tubes arranged. It is possible to design a design that matches the size of the irradiation object 36 to be conveyed by the transfer machine.

FIG. 3B is a modified example of the embodiment shown in FIG. 3A. Two ultraviolet irradiation devices 30 are provided along the traveling path of the automatic carrier 35 so as to cover the traveling path in series in a tunnel shape. Thus, the irradiation object 36 that is mounted on the conveyor 35 and moves is exposed to the ultraviolet irradiation from the two irradiation devices 30 twice in succession. The continuous irradiation configuration is effective in that the speed of the automatic carrier 35 is increased to improve the processing speed and that the total irradiation dose is increased at a low speed.

Although the two ultraviolet irradiation devices 30 may have the same configuration, they may have different emission wavelengths and emission wavelength widths. The emission wavelength is realized by adjusting the material of the phosphor layer 3 (see FIG. 1A) of each emission tube 1 which is a unit emission source.

FIG. 3C is another modification of the embodiment shown in FIG. 3A, in which the two ultraviolet irradiation devices 30 are arranged so as to wrap the transport path from above and below along the travel path of the automatic transport machine 35. Has been done. The three-dimensional irradiation object 36 that is mounted on the carrier 35 and moves converges from each of the irradiation device 30 with the curved light emitting surface facing down and the irradiation device 30 with the curved light emitting surface facing up. Both sides are exposed to the irradiated ultraviolet rays, and the entire surface is irradiated. In this case, the transporter 37 needs to transmit the irradiation ultraviolet rays from the lower irradiation device 30 at least in the portion where the irradiation target is placed.

Therefore, in addition to making the transport belt of the transport machine 35 have a mesh configuration, measures such as configuring the mounting portion with an ultraviolet-transparent fluororesin film are taken. Further, as in the case of FIG. 3B, it is possible to increase the irradiation processing efficiency by further adding the upper and lower ultraviolet irradiation devices 30 along the traveling path of the conveyor, and to make the emission spectra of each different. It is also possible to keep it.

(Embodiment 3)
4 (a) and 4 (b) are schematic perspective views showing two types of configurations of the ultraviolet irradiation device of the third embodiment according to the present invention, respectively. This embodiment is characterized by a composite light emitting surface obtained by combining two or more flat light emitting surfaces at an angle to obtain a self-condensing function.

That is, FIG. 4A shows an ultraviolet irradiation device 40 in which the planar light source device of the light emitting tube array structure is bent in two toward the light emitting surface side along a line 41 along the longitudinal direction of the light emitting tube at the center thereof. There is. The optical axes 22 of the light emitting tubes 1 constituting the two light emitting surfaces 10A and 10B formed by bending are oriented so as to converge with each other toward the vertical surface of the bending line 41, and are placed at an extension position of the central vertical surface. It is possible to effectively irradiate the object to be irradiated with ultraviolet rays.

The ultraviolet irradiation device 70 of FIG. 4B is composed of three composite light emitting surfaces 10A, 10B, and 10C bent in a rectangular shape, and the optical axis of the light emitting tube 1 constituting each light emitting surface is surrounded by the light emitting surface. It will gather in the irradiation space.

The folded composite light emitting surfaces 10A, 10B, and 10C may be configured as independent surface light source devices, or the electrode arrangement substrate 13 may be configured in common for each light emitting surface. By passing a transport belt (not shown) through the irradiation space surrounded by the composite light emitting surface, it is possible to effectively irradiate the object to be irradiated on the moving transport belt with ultraviolet rays.

(Other variants)
As described at the beginning, the ultraviolet irradiation device having a self-collecting function of the present invention has a basic configuration of an array-shaped flexible surface light source device in which a plurality of light emitting tubes using gas discharge are arranged side by side, and the light emitting surface thereof is used. It is characterized in that the light emitting axis of each light emitting tube is converged toward an irradiation target by bending it into a curved surface shape or an angled composite plane shape.

In the basic configuration of the light source device illustrated in FIG. 1, a pair of X electrodes 14X and Y electrodes 14Y are arranged in series with respect to the elongated glass tube 2 by dividing the longitudinal direction into two, but a plurality of pairs of electrodes are further arranged. It can be arranged in series to accommodate the lengthening of the light emitting tube. By the way, when the length of the glass tube 2 is about 20 cm, effective light emission is achieved by arranging two pairs of XY electrode pairs having a length of 5 cm sandwiching the electrode slit G in the longitudinal direction of the glass tube in series at predetermined intervals. An ultraviolet light emitting tube having a length of 20 cm can be constructed.

A flexible resin film is suitable for the insulating substrate 13 for supporting the electrodes shown in FIG. 1, but a rigid glass or ceramic having a surface corresponding to each of a curved surface or a composite plane along the degree of bending of the light emitting surface in advance. A substrate may be used instead. Further, a heat radiation element such as a metal heat radiation fin having an independent shape corresponding to the back pattern of the band-shaped common X electrode 14X and the Y electrode 14Y extending in the arrangement direction of the light emitting tube 1 is provided so as to be in close contact with the back side of the electrode substrate. As a result, heat dissipation of the light source device can be promoted and the luminous efficiency can be kept stable.

The ultraviolet irradiation intensity is strengthened by converging the optical axes of a plurality of light emitting tubes toward the irradiation target, and the intensity adjustment is performed by intermittently driving a sinusoidal voltage from the inverter power supply 17 shown in FIG. 1 (c) in a burst format. This can be done by changing the duty ratio when the application is applied. Further, in the configuration in which the irradiation object mounted on the automatic carrier 35 and moving is irradiated with ultraviolet rays as shown in the embodiment of FIG. 3, the application of the drive sinusoidal voltage is synchronized with the transfer speed of the irradiation object. It is possible to suppress the heat generation of the light source device by performing it intermittently in the passage time width.

In any case, according to the ultraviolet irradiation device of the present invention, there is an advantage that the condensing function can be controlled by the shape of the light emitting surface itself without using an optical element such as a reflection mirror or a condensing lens, and the ultraviolet application surface can be expanded. Extremely beneficial to.

1: Ultraviolet luminescent gas discharge tube (light emitting tube)
2: Glass tube 3: Ultraviolet phosphor layer 10: Light emitting tube array structure (surface light source device)
11: Insulation layer 12: Adhesive 13: Insulation substrate 14: Electrode pair 14X: X electrode 14Y: Y electrode 15: Electrode structure 17: Alternate power supply G: Electrode slit 20: Surface light source

Claims (4)

In an ultraviolet irradiation device provided with a surface light source device having a light emitting surface curved or bent toward an irradiation target.
The surface light source device has a configuration of a light emitting tube array composed of a flexible insulating substrate and a plurality of ultraviolet emitting gas discharge tubes supported in parallel on the insulating substrate to form the light emitting surface, and the insulating substrate. Is provided with at least one pair of electrodes having a length of 5 times or more the width of the electrode slits and extending symmetrically on both sides with an electrode slit that commonly crosses the plurality of ultraviolet emitting gas discharge tubes.
An ultraviolet irradiation device characterized in that the light emitting surface of the surface light source device having the light emitting tube array configuration is curved or bent so as to cover the traveling path of the automatic carrier. The ultraviolet irradiation device according to claim 1, wherein a plurality of surface light source devices that cover the traveling path of the automatic carrier in a tunnel shape are arranged in series along the traveling path. A first surface light source device that covers the traveling path of the automatic carrier with a light emitting surface curved downward from above and a second surface light source device covering the traveling path of the automatic carrier with a light emitting surface curved upward from below are arranged in series. The ultraviolet irradiation device according to claim 1. The ultraviolet irradiation device according to claim 2, wherein the plurality of surface light source devices irradiate ultraviolet rays having different wavelengths.

Images