JP2006351670A - Ultraviolet irradiation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultraviolet irradiation device which can achieve a large dose of ultraviolet ray by efficiently utilizing lights emitting from a short-arc type discharge lamp as a light source lamp, as well as a large dose of light even in a range of wavelemngth of 350 nm or less in ultraviolet. <P>SOLUTION: The ultraviolet irradiation device is provided with a concave reflection mirror (hereinafter called as mirror), a front glass provided in the direction of light projection of the light projection port of the mirror, and a short-arc type discharge lamp (hereinafter called as lamp) with a mercury enclosed therein. The lamp is arranged in a manner that the focus of the mirror may coincide with a center between lamp electrodes and the optical axis of the mirror may also coincide with the arc axis of the lamp. The mirror is provided with a reflection surface that reflects 80% or more of lights in a specific wavelength range and 50% or more of lights in another specific wavelength range. The front glass has a transmission factor of at least 50% or more to lights in a specific wavelength range, and it reflects at least 50% or more of lights in another specific wavelength range. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an ultraviolet irradiation apparatus, and more particularly to an ultraviolet irradiation apparatus used as a light source for performing an exposure process in a manufacturing process of a semiconductor device, a manufacturing process of a liquid crystal display substrate, and the like.

  2. Description of the Related Art Conventionally, in a semiconductor device manufacturing process or a liquid crystal display substrate manufacturing process, an ultraviolet irradiation apparatus provided with a light source lamp composed of a high-pressure mercury lamp having a power consumption of several kW to several tens kW as a light source for performing an exposure process. Widely used.

As a certain type of such an ultraviolet irradiation device, for example, as shown in FIG. 10, a light source lamp 41 is disposed so as to cover the light source lamp 41, and visible light and heat rays are transmitted through the inner surface thereof. The concave reflection mirror 42 has a reflection surface that reflects ultraviolet rays and projects the ultraviolet rays emitted from the light source lamp 41 forward (upward in FIG. 10) with high efficiency, and the light projection of the concave reflection mirror 42. A heat ray cut filter 43 that reflects visible light and heat rays and transmits ultraviolet rays is provided in front of the light projection direction (upward in FIG. 10) of the opening 42A. Among the light projected from the light projection port 42 </ b> A, there is a configuration in which the ultraviolet light that has passed through the heat ray cut filter 43 is irradiated to the ultraviolet light irradiation object.
The ultraviolet irradiation device of FIG. 10 is a device for performing spot cure processing. In FIG. 10, 45 is a shutter, 46 is an optical fiber unit, and 47 is a lens unit facing the ultraviolet irradiation object.

  In addition, in the ultraviolet irradiation device particularly used in the manufacturing process of the liquid crystal display substrate, in order to cope with the recent increase in the area of the liquid crystal display substrate, it is required to expand the ultraviolet irradiation region. Since the processing capability of the ultraviolet irradiating apparatus itself is reduced only by expanding the range, it is necessary to increase the ultraviolet irradiation amount while expanding the ultraviolet irradiation region.

  Thus, as a light source lamp of an ultraviolet irradiation device used in a manufacturing process of a liquid crystal display substrate, a high-pressure mercury lamp having a power consumption of 25 kW is currently used in order to obtain a large ultraviolet irradiation amount. When a larger amount of ultraviolet irradiation is required, the discharge vessel and electrode material, which are constituent members of the high-pressure mercury lamp, are increased in size to cope with it, and accordingly, the high-pressure mercury lamp itself is increased in size. There is a possibility that the ultraviolet irradiation device is increased in size, and the manufacturing cost and the number of manufacturing steps related to the light source lamp are significantly increased.

  Regarding the light source lamp, in order to obtain a large ultraviolet irradiation amount in the ultraviolet irradiation device, it is conceivable to increase its luminous efficiency, for example, by increasing the amount of the luminescent substance sealed in the discharge vessel. In order to obtain such a lamp, first, it is necessary to develop a lamp structure that can withstand a high load and a component for constituting the lamp.

On the other hand, in the ultraviolet irradiation device, it is necessary to increase the amount of ultraviolet irradiation, and there is also a demand for energy saving. Therefore, it is possible to improve efficiency for obtaining a large amount of ultraviolet irradiation with high energy efficiency. This is an extremely important issue.
Thus, by providing a coating film on the discharge vessel as a light source lamp of the ultraviolet irradiation device, a part of the light generated in the light emitting space surrounded by the discharge vessel is not emitted toward the outside of the discharge vessel. It has been attempted to increase the luminous efficiency of the light source lamp by using this light while being kept in the discharge vessel by reflecting the light, but the temperature of the discharge vessel will be as high as about 1000 ° C. during lighting. There is a problem that the coating film peels off.

In addition, as the ultraviolet irradiation device, a plurality of ultra-high pressure mercury lamps (for example, refer to Patent Document 1) in which the vapor pressure of mercury at the time of lighting is 8 × 10 ⁶ Pa (about 80 atm) or more is arranged as a light source lamp. What has been prepared in the state which has been prepared is proposed (for example, refer patent document 2).
In such an ultraviolet irradiation device, an ultra-high pressure mercury lamp that operates at a high mercury vapor pressure is used as a light source lamp, so that it has a broad wavelength along with emission line spectra related to mercury such as i-line, h-line, and g-line. Since a continuous spectrum over a region can be obtained, a large ultraviolet irradiation amount can be obtained.
However, since such an ultra-high pressure mercury lamp emits visible light as well as ultraviolet light with a large radiation dose, when used as a light source lamp of an ultraviolet irradiation device that uses only ultraviolet light, As a result, there is a problem that the energy emitted from the light source lamp cannot be used with high efficiency in the ultraviolet irradiation device.

  In addition, as an ultraviolet irradiation device used as a light source for performing an exposure process, a device that is mainly irradiated with light (i-line) having a wavelength of 365 nm in the ultraviolet region has been widely used. As an object to be irradiated, those that require irradiation with light of a wavelength of 350 nm or less in the ultraviolet region have appeared, and in order to cope with this, light of a region of a wavelength of 350 nm or less is irradiated with a large dose. What can be done is also desired.

Japanese Patent No. 2829339 JP 2004-361746 A

The present invention has been made based on the above circumstances, and its purpose is to increase the amount of ultraviolet irradiation by utilizing light emitted from a short arc type discharge lamp, which is a light source lamp, with high efficiency. An object of the present invention is to provide an ultraviolet irradiation apparatus that can be obtained.
Another object of the present invention is to provide an ultraviolet irradiation apparatus capable of obtaining light in a region of a wavelength of 350 nm or less in the ultraviolet region with a large irradiation amount.

The ultraviolet irradiation device of the present invention includes a concave reflection mirror, a front glass provided in front of the light projection direction of the light projection port of the concave reflection mirror, and a short arc type discharge lamp in which mercury is enclosed. In the short arc type discharge lamp, the focal point of the concave reflection mirror and the center of the electrode of the short arc type discharge lamp substantially coincide, and the optical axis of the concave reflection mirror and the arc axis of the short arc type discharge lamp Are placed in a matching state,
The concave reflecting mirror has a reflecting surface that reflects 80% or more of light in a wavelength region of 350 to 450 nm and reflects 50% or more of light in a wavelength region of 450 to 590 nm;
The front glass has a transmittance of at least 50% for light in the entire region having a wavelength of 350 to 400 nm, and reflects at least 50% of light in the region of a wavelength of 530 to 590 nm.

The ultraviolet irradiation device of the present invention includes a concave reflection mirror, a front glass provided in front of the light projection direction of the light projection port of the concave reflection mirror, and a short arc type discharge lamp in which mercury is enclosed. In the short arc type discharge lamp, the focal point of the concave reflection mirror and the center of the electrode of the short arc type discharge lamp substantially coincide, and the optical axis of the concave reflection mirror and the arc axis of the short arc type discharge lamp Are placed in a matching state,
The concave reflecting mirror has a reflecting surface that reflects 80% or more of light in a wavelength region of 300 to 450 nm and reflects 50% or more of light in a wavelength region of 450 to 590 nm;
The front glass has a transmittance of at least 50% for light in the entire region having a wavelength of 300 to 400 nm, and reflects at least 50% of light in the region of a wavelength of 530 to 590 nm.

  In the ultraviolet irradiation device of the present invention, it is preferable that the maximum value of the spectral reflectance in the wavelength region of light to be reflected at a specific ratio is 95% or more in each of the concave reflecting mirror and the front glass.

In the ultraviolet irradiation apparatus of the present invention, it is preferable that 0.08 mg / mm ³ or more of mercury is enclosed in the short arc type discharge lamp.

According to the ultraviolet irradiation device of the present invention, the concave reflecting mirror that reflects ultraviolet light with a specific reflectance and also reflects visible light with a specific reflectance, and transmits ultraviolet light and reflects visible light with a specific reflectance. Since it is provided with a front glass that reflects, ultraviolet rays radiated from the short arc type discharge lamp in a direction other than the light projection direction are reflected in the light projection direction by being reflected by the concave reflecting mirror. It can be projected from the light projection port of the concave reflecting mirror together with ultraviolet rays, and the visible light emitted from this short arc type discharge lamp is reflected by at least one of the concave reflecting mirror and the front glass. A plasm generated in the light emitting space by the arc discharge is guided into the light emitting space in the short arc discharge lamp. It is absorbed in and converted into thermal energy, thereby increasing the plasma temperature, so that the luminous efficiency of the short arc discharge lamp can be increased, and both the concave reflecting mirror and the front glass are Reflects light in a wavelength range of 530 to 590 nm emitted from a short arc discharge lamp in which mercury is sealed as a luminescent substance at a high light intensity. Therefore, a wavelength of 530 to 590 nm in the visible range is reflected. The light in the region can be effectively used to raise the plasma temperature.
Therefore, according to the ultraviolet irradiation device of the present invention, the light emitted from the short arc type discharge lamp, which is a light source lamp, can be used with high efficiency, whereby a large ultraviolet irradiation amount can be obtained.

  Moreover, in the ultraviolet irradiation device of the present invention, in particular, a concave reflecting mirror that reflects light in a wavelength region of 300 to 450 nm at a specific ratio is used, and the front glass has a wavelength of 300 to 450 nm. By using a material that transmits light at a specific ratio, light having a wavelength of 350 nm or less in the ultraviolet region can be obtained with a large dose.

In the ultraviolet irradiation device of the present invention, as the short arc type discharge lamp, a mercury-filled amount of 0.08 mg / mm ³ or more is used. Since a spectrum continuous over a wide wavelength region is obtained together with an emission line spectrum relating to mercury such as g-line, ultraviolet rays and visible rays are emitted from the short arc type discharge lamp with a large radiation amount. A large amount of ultraviolet irradiation can be obtained.

  Hereinafter, embodiments of the present invention will be described in detail.

<First Embodiment>
FIG. 1 is an explanatory view schematically showing an example of the configuration of the ultraviolet irradiation device of the present invention.
The first ultraviolet irradiation device is concave and forms a reflection space, and has a concave reflection mirror 11 having a circular light projection port 11A at its front end (right end in FIG. 1), and the concave reflection mirror 11. And a front glass 13 provided in front of the light projection port 11A in the light projection direction (rightward in FIG. 1), and a spherical arc tube portion that forms a light emission space in the reflection space of the concave reflection mirror 11 21A and a rod-shaped sealing tube portion 21B extending outward in the tube axis direction, that is, forward and backward in the optical axis direction, following both ends thereof, and having a discharge vessel 21 made of, for example, silica glass, In the space, a short arc type discharge lamp 15 having a structure in which a cathode (not shown) and an anode (not shown) are arranged so as to face each other, the focal point of the concave reflecting mirror 11 and the short arc type discharge. And the center between the electrodes of the amplifier 15 is substantially coincident, and the optical axis of the concave reflecting mirror 11 and the arc axis of the short arc discharge lamp 15 are substantially horizontally arranged. .
In the example of this figure, the front glass 13 has a surface area equal to or larger than the area of the light projection port 11A of the concave reflecting mirror 11, and has a shape that can cover the light projection port 11A.

  The concave reflecting mirror 11 is formed by providing a reflecting surface on the inner surface of a concave base material made of, for example, borosilicate, and the reflecting surface is preferably 80% or more of light in a wavelength region of 350 to 450 nm. Reflects 95% or more and reflects light in the wavelength region of 450 to 590 nm by 50% or more, preferably 95% or more.

  When the reflectivity of light in the wavelength range of 350 to 450 nm of the reflecting surface of the concave reflecting mirror 11 is excessively low, ultraviolet rays emitted from the short arc type discharge lamp 15 are forwarded from the light projection port 11A with high efficiency. When the light cannot be projected and the reflectance of light in the wavelength region of 450 to 590 nm is too small, the short arc type discharge lamp 15 led into the light emission space of the short arc type discharge lamp 15 is used. The amount of emitted visible light is reduced, and the plasma temperature cannot be sufficiently increased in the light emission space.

  The concave reflecting mirror 11 transmits the heat rays for the purpose of preventing the concave reflecting mirror 11 itself and the short arc type discharge lamp 15 from being overheated due to the high temperature of the reflecting space. is there.

The reflecting surface of the concave reflecting mirror 11 is made of, for example, a dielectric multilayer film in which a total of about 50 layers of niobium oxide layers and silicon oxide layers are laminated, and the thickness thereof is, for example, 4 μm. is there.
Here, as the dielectric multilayer film, in addition to a laminate of a niobium oxide layer and a silicon oxide layer, for example, a laminate of a hafnium oxide layer and a silicon oxide layer, a tantalum oxide layer and a silicon oxide layer A layer formed by stacking a zirconium oxide layer and a silicon oxide layer can also be used.

  The concave reflecting mirror 11 has a wavelength region of light that should be reflected at a specific ratio, specifically, a region having a wavelength of 350 to 450 nm where the reflectance is 80% or more and a reflectance of 50% or more. It is preferable that the maximum value of the spectral reflectance in the wavelength range of 450 to 590 nm, that is, the wavelength range of 350 to 590 nm is 95% or more.

The front glass 13 is arranged on the optical path of the light emitted from the short arc type discharge lamp 15 and projected from the light projection port 11A of the concave reflection mirror 11 and irradiated to the ultraviolet irradiation object. The transmittance for light in the entire region of at least a wavelength of 350 to 400 nm is 50% or more, preferably 95% or more, and the light in the region of a wavelength of 530 to 590 nm is reflected by 50% or more, preferably 95% or more. .
Here, “transmittance with respect to light in the entire wavelength range of 350 to 400 nm” indicates an average value of spectral transmittance in the wavelength range of 350 to 400 nm.

  When the transmittance of the entire area of the front glass 13 with a wavelength of 350 to 400 nm is excessively small, ultraviolet rays emitted from the short arc type discharge lamp 15 and projected from the light projection port 11A of the concave reflecting mirror 11 are used. When the object to be irradiated with ultraviolet rays cannot be irradiated with high efficiency and the reflectance of light in the wavelength region of 530 to 590 nm is excessively small, the light is introduced into the light emitting space of the short arc type discharge lamp 15. As a result, the amount of visible light emitted from the short arc discharge lamp 15 is reduced, and the plasma temperature cannot be sufficiently increased in the light emitting space.

The front glass 13 has a configuration in which, for example, a total of about 40 tantalum oxide layers and silicon oxide layers are alternately laminated on at least one surface of a base material made of, for example, a glass plate. A functional thin film made of a multilayer film or the like is provided.
Here, as the dielectric multilayer film, in addition to a laminate of a niobium oxide layer and a silicon oxide layer, for example, a laminate of a hafnium oxide layer and a silicon oxide layer, a tantalum oxide layer and a silicon oxide layer A layer formed by stacking a zirconium oxide layer and a silicon oxide layer can also be used.

  Further, the front glass 13 has a maximum spectral reflectance of 95% or more in a wavelength region of light to be reflected at a specific ratio, specifically, in a wavelength region of 530 to 590 nm where the reflectance is 50% or more. It is preferable that

The short arc type discharge lamp 15 is formed by enclosing mercury as a luminescent substance, and the amount of mercury enclosed is preferably 0.08 mg / mm ³ or more, particularly 0.08 to 0.3 mg / mm. ³ is preferred.
When the amount of mercury enclosed in the short arc type discharge lamp 15 is 0.08 mg / mm ³ or more, the short arc type discharge lamp 15 has a wide spectrum of emission lines related to mercury such as i-line, h-line and g-line. Since a continuous spectrum is obtained over the wavelength region, ultraviolet rays and visible rays are emitted from the short arc type discharge lamp 15 with a large radiation amount. Therefore, a larger ultraviolet radiation amount is applied to the first ultraviolet radiation device. Obtainable.

  In the first ultraviolet irradiation apparatus configured as described above, when the short arc type discharge lamp 15 is turned on, the light emitted in the light projection direction out of the light emitted from the short arc type discharge lamp 15. Are projected from the light projection port 11A of the concave reflection mirror 11, and the ultraviolet rays and visible light reflected by the concave reflection mirror 11 out of the light emitted in directions other than the light projection direction are emitted from the light projection port 11A. Of the light projected and projected from the light projection port 11 </ b> A, ultraviolet rays that have passed through the front glass 13 are irradiated to the ultraviolet irradiation object.

  Then, visible light of the light emitted from the short arc type discharge lamp 15 is finally formed into the concave surface by at least one of the concave reflection mirror 11 and the front glass 13 as shown by a one-dot chain line in FIG. By being reflected back to the focal position of the reflecting mirror 11, it is guided into the light emission space in the short arc discharge lamp 15 and is absorbed in the plasma generated in the light emission space by the arc discharge to become thermal energy. Since the plasma temperature in the light emitting space rises due to the conversion, the luminous efficiency of the short arc type discharge lamp 15 increases, and both the concave reflecting mirror 11 and the front glass 13 are at least a luminescent substance. As a short arc type discharge lamp 15 in which mercury is enclosed as In order to raise the plasma temperature without wasting light in the region of wavelength 530 to 590 nm in the visible region because it reflects light in the region of wavelength 530 to 590 nm emitted with a large light intensity. Can be used effectively.

  In addition, light (visible light) in a wavelength region of 530 to 590 nm is repeatedly reflected by the concave reflecting mirror 11 and the front glass 13 to cause multiple reflection, so that the light emission space in the short arc discharge lamp 15 of the visible light is generated. In the mercury vapor atmosphere, the plasma temperature is sufficiently increased in the light emitting space even if the proportion of light absorbed in the region of wavelength 530 to 590 nm is small. Can be made. This is notable because the probability of multiple reflections increases as the reflectance of light in the wavelength range of 530 to 590 nm of each of the concave reflecting mirror 11 and the front glass 13 increases. .

Therefore, according to such a first ultraviolet irradiation device, since the visible light is used together with the ultraviolet light, for example, as shown in FIG. 2, the light source lamp 31 and the light source lamp 31 are covered. A reflective surface that transmits visible light (VIS) and heat rays (IR) and reflects ultraviolet light (UV) is provided on the inner surface thereof, and has a characteristic as shown in FIG. A concave reflecting mirror 32 that projects ultraviolet rays radiated from the lamp 31 forward (rightward in FIG. 2) with high efficiency, and a light projecting direction forward (right in FIG. 2) of the light projection port 32A of the concave reflecting mirror 32. 4) and a heat ray cut filter 33 that reflects visible light (VIS) and heat rays (IR) and transmits ultraviolet rays (UV), and has the characteristics shown in FIGS. The conventional ultraviolet irradiation which has the structure by which the ultraviolet-ray which was projected from the light projection port 32A of the concave reflective mirror 32 among the lights radiated | emitted from the light source lamp 31, and permeate | transmitted the heat ray cut filter 33 is irradiated with respect to a ultraviolet irradiation target object. Compared with the apparatus, the light emitted from the short arc type discharge lamp 15 which is a light source lamp can be utilized with high efficiency, and thereby a large ultraviolet irradiation amount can be obtained.
In FIG. 3, the solid line indicates the spectral reflectance related to the reflective surface having the characteristic of mainly reflecting light having a wavelength of 365 nm, and the broken line indicates the spectral reflection related to the reflective surface having the characteristic of mainly reflecting light having a wavelength of 240 to 365 nm. These are all under the condition of a light incident angle of 15 °.

<Second Embodiment>
The second ultraviolet irradiation device, as a concave reflecting mirror, reflects light in a wavelength region of 300 to 450 nm by 80% or more, preferably 95% or more, and light in a wavelength region of 450 to 590 nm by 50% or more, preferably Has the same configuration as that of the first ultraviolet irradiation apparatus according to the first embodiment, except that a reflection surface that reflects 95% or more is provided.

  When the reflectivity of light in the wavelength range of 300 to 450 nm on the reflecting surface of the concave reflecting mirror is too small, the ultraviolet rays emitted from the short arc type discharge lamp are projected forward from the light projection port with high efficiency. If the reflectance of light in the wavelength region of 450 to 590 nm is too low, visible light emitted from the short arc discharge lamp is guided into the light emission space of the short arc discharge lamp. As a result, the plasma temperature cannot be sufficiently increased in the light emitting space.

  When the transmittance of the entire area of the front glass with a wavelength of 300 to 400 nm is excessively low, the ultraviolet rays emitted from the short arc type discharge lamp and projected from the light projection port of the concave reflecting mirror are ultraviolet rays with high efficiency. When the irradiation object cannot be irradiated and the reflectance of light in the wavelength region of 530 to 590 nm is excessively small, the short is guided into the light emission space of the short arc discharge lamp 15. The amount of visible light emitted from the arc-type discharge lamp is reduced, and the plasma temperature cannot be sufficiently increased in the light emission space.

  In the second ultraviolet irradiation device having such a configuration, when the short arc type discharge lamp is turned on, the light emitted in the light projection direction out of the light emitted from the short arc type discharge lamp is concave. Ultraviolet rays and visible rays that are projected from the light projection port of the reflection mirror and reflected by the concave reflection mirror out of the light emitted in a direction other than the light projection direction are projected from the light projection port. The ultraviolet rays that have passed through the front glass out of the light projected from are irradiated to the ultraviolet irradiation object.

  According to the second ultraviolet irradiation device configured as described above, like the first ultraviolet irradiation device, the concave reflection that reflects ultraviolet light with a specific reflectance and also reflects visible light with a specific reflectance. Since it comprises a mirror and a front glass that transmits ultraviolet rays and reflects visible light with a specific reflectance, ultraviolet rays radiated from a short arc type discharge lamp in a direction other than the light projection direction, It can be projected from the light projection port of the concave reflecting mirror together with the ultraviolet rays radiated in the light projecting direction by being reflected by the concave reflecting mirror, and the visible light emitted from this short arc type discharge lamp is concave. Is reflected by at least one of the mirror-like reflecting mirror and the front glass so as to finally return to the focal position of the concave reflecting mirror. The short arc type discharge is introduced into the light emission space in the arc discharge lamp, absorbed in the plasma generated in the light emission space by the arc discharge, and converted into thermal energy, thereby increasing the plasma temperature. The luminous efficiency of the lamp can be increased, and the wavelength 530 to be emitted with high light intensity from a short arc type discharge lamp in which both the concave reflecting mirror and the front glass are filled with mercury as a luminescent material. Since the light in the 590 nm region is reflected, the light in the visible region having a wavelength of 530 to 590 nm can be effectively used to raise the plasma temperature.

  Further, light (visible light) in the wavelength region of 530 to 590 nm is repeatedly reflected by the concave reflecting mirror and the front glass, and multiple reflection occurs, so that the visible light in the light emission space in the short arc discharge lamp is generated. Since the absorption is repeatedly performed, the plasma temperature can be sufficiently increased in the light emission space even if the ratio of the light having a wavelength of 530 to 590 nm in the mercury vapor atmosphere is small. it can. This is remarkable because the probability of multiple reflection occurring increases as the reflectance of light in the wavelength range of 530 to 590 nm of each of the concave reflecting mirror and the front glass increases.

Therefore, according to such a second ultraviolet irradiation device, light emitted from the short arc type discharge lamp which is a light source lamp can be used with high efficiency, and thereby a large ultraviolet irradiation amount can be obtained. it can.
In the second ultraviolet irradiation device, the concave reflecting mirror reflects light in the wavelength region of 300 to 450 nm at a specific ratio, and the front glass specifies light in the entire wavelength region of 300 to 450 nm. Therefore, light having a wavelength of 350 nm or less in the ultraviolet region can be obtained with a large irradiation amount.

In the ultraviolet irradiation apparatus of the present invention, the first ultraviolet irradiation apparatus or the second ultraviolet irradiation apparatus is selected according to the wavelength region of the ultraviolet rays to be irradiated to the ultraviolet irradiation target. For example, the semiconductor device manufacturing process and the liquid crystal display Since it can be used as a light source for performing an exposure process in a manufacturing process of a substrate, and a large UV irradiation amount can be obtained with high energy efficiency even if a small light source lamp is used instead of a large light source lamp, And can be suitably used in the manufacturing process of a liquid crystal display substrate having a large area.
Specifically, when used in the manufacturing process of a large-area liquid crystal display substrate, the ultraviolet irradiation device is formed by arranging a plurality of ultraviolet irradiation units composed of, for example, a short arc type discharge lamp, a concave reflecting mirror, and a front glass. A plurality of short arc discharge lamps having a configuration, or a configuration in which a plurality of light projection units comprising a short arc type discharge lamp and a concave reflecting mirror are arranged along the ultraviolet transmission surface of a common front glass It is preferable that it has a structure provided with.

As mentioned above, although embodiment of this invention was described concretely, the ultraviolet irradiation device of this invention is not limited to said example, A various change can be added.
For example, the ultraviolet irradiation device transmits a short arc discharge lamp in which mercury is enclosed, a concave reflecting mirror that reflects ultraviolet light with a specific reflectance and also reflects visible light with a specific reflectance, and transmits ultraviolet light. In addition, as long as it includes a front glass that reflects visible light with a specific reflectance, an appropriate component member may be provided depending on the application.

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

[Experimental Example 1]
In accordance with the configuration shown in FIG. 1, a first experimental ultraviolet irradiation device, a second experimental ultraviolet irradiation device, and a first experimental ultraviolet irradiation device comprising a concave reflecting mirror, a front glass, and a short arc type discharge lamp. 3 experimental ultraviolet irradiation apparatuses, a fourth experimental ultraviolet irradiation apparatus, and a fifth experimental ultraviolet irradiation apparatus were produced.

In the produced first experimental ultraviolet irradiation device (hereinafter also referred to as “experimental device (1)”), a niobium oxide layer and a silicon oxide layer are formed on the inner surface of the concave substrate as a concave reflecting mirror. And a dielectric multilayer film having a thickness of 4 μm, in which a total of 50 layers are alternately stacked, and as shown in FIG. 6, the reflectance of light in the wavelength region of 350 to 460 nm is 90% or more, and the wavelength A substrate having a reflective surface with a reflectance of 90% of light in the region of 530 to 590 nm (hereinafter also referred to as “light in a specific visible region”) is used, and a substrate made of a glass plate as a front glass On one surface, a functional thin film made of a dielectric multilayer film having a thickness of 3 μm and having a structure in which a total of 40 tantalum oxide layers and silicon oxide layers are laminated, as shown in FIGS. 7 and 8, For light in the entire region with a wavelength of 350 to 400 nm As a short arc type discharge lamp having a transmittance of 50% or more and reflecting light with a wavelength of 500 to 640 nm of 90% or more, the enclosed amount of mercury is 15 mg (0.2 mg / mm ³ ), An ultrahigh pressure mercury lamp having an operating pressure of about 20 MPa and a spectrum shown in FIG. 9 was used.

The produced second experimental ultraviolet irradiation device (hereinafter also referred to as “experimental device (2)”) is a concave reflecting mirror, and has a light reflectance of 90% or more in a wavelength region of 300 to 460 nm. In addition, the apparatus has the same configuration as that of the experimental apparatus (1) except that a reflection surface having a reflectance of light in a specific visible range of 50% is used.
The produced third experimental ultraviolet irradiation device (hereinafter also referred to as “experimental device (3)”) is a concave reflecting mirror, and has a light reflectance of 90% or more in a wavelength region of 300 to 460 nm. In addition, the apparatus has the same configuration as that of the experimental apparatus (1) except that a reflection surface having a reflectance of 30% of light in a specific visible range is used.
The produced fourth experimental ultraviolet irradiation device (hereinafter also referred to as “experimental device (4)”) is a concave reflecting mirror, and has a light reflectance of 90% or more in a wavelength region of 350 to 460 nm. In addition, the apparatus has the same configuration as that of the experimental apparatus (1) except that a reflection surface having a reflectance of 10% of light in a specific visible range is used.
The manufactured fifth experimental ultraviolet irradiation device (hereinafter also referred to as “experimental device (5)”) is a concave reflecting mirror, and has a reflectance of 90% or more in the wavelength region of 350 to 460 nm. In addition, the apparatus has the same configuration as that of the experimental apparatus (1) except that a reflection surface having a reflectance of light in a specific visible range of less than 5% is used.
The concave reflecting mirrors constituting the experimental device (2) to the experimental device (5) each have the same shape as the concave reflecting mirror constituting the experimental device (1).

For each of the experimental apparatus (1) to the experimental apparatus (5) produced, the output value of the ultraviolet rays that are projected through the front glass when the short arc type discharge lamp is turned on under the same lighting conditions. confirmed. The results are shown in Table 1.
In Table 1, the “ultraviolet ray output rate” is a relative value of the ultraviolet ray output values of other experimental devices when the ultraviolet ray output value of the experimental device (5) is 100. Although this experimental apparatus (5) is provided with a front glass, the front glass is almost the same as the heat ray cut filter provided in the conventional ultraviolet irradiation apparatus as shown in FIG. 10 and FIG. Since it has the same ultraviolet reflection characteristic and visible light reflection characteristic (see FIGS. 4 and 5), the ultraviolet output value according to the experimental device (5) is evaluated as the ultraviolet output value of the conventional ultraviolet irradiation device. Went.

From the results shown in Table 1, the ultraviolet irradiation device is a specific visible region having a wavelength of 530 to 590 nm projected from the light projection port of the concave reflecting mirror as in the experimental device (1) to the experimental device (4). By reflecting light by 50% or more by the front glass and guiding it into the reflection space of the concave reflecting mirror, and having a configuration in which the light in the specific visible range is also reflected by the concave reflecting mirror. Without changing the short arc type discharge lamp as the light source lamp to a large one having high luminous efficiency, light in a specific visible range is almost reflected by the concave reflecting mirror such as the experimental device (5). Compared with an ultraviolet irradiation device having a configuration without this, a large ultraviolet output value can be obtained, and, like the experimental device (1) and the experimental device (2), a concave reflecting mirror is used. By the reflectance of the light of the constant in the visible region of 50% or more, it is possible to increase the UV output value of 5% or more was confirmed.
That is, according to the ultraviolet irradiation apparatus having a configuration including a concave reflecting mirror and a front glass having a characteristic of reflecting light in a wavelength region of 530 to 590 nm at a reflectance of 50% or more, and using the light in this wavelength region The light emitted from the short arc type discharge lamp can be used with high efficiency, which makes it extremely efficient to obtain a large amount of UV irradiation with high energy efficiency compared to conventional UV irradiation equipment. It was confirmed that the output value of ultraviolet rays was increased by a large ratio of 5% or more, that is, a large amount of ultraviolet irradiation was obtained.

It is explanatory drawing which shows roughly an example of a structure of the ultraviolet irradiation device of this invention. It is explanatory drawing which shows schematically an example of a structure of the conventional ultraviolet irradiation device. It is a graph which shows the spectral reflectance which concerns on the reflective surface of the concave reflective mirror which comprises the ultraviolet irradiation device of FIG. It is a graph which shows the spectral transmittance which concerns on the heat ray cut filter which comprises the ultraviolet irradiation device of FIG. It is a graph which shows the spectral reflectance which concerns on the heat ray cut filter which comprises the ultraviolet irradiation device of FIG. It is a graph which shows the spectral reflectance which concerns on the reflective surface of the concave reflective mirror which comprises the 1st experimental ultraviolet irradiation device produced in Experimental example 1. FIG. It is a graph which shows the spectral transmission factor which concerns on the front glass which comprises the 1st experimental ultraviolet irradiation device produced in Experimental example 1. FIG. It is a graph which shows the spectral reflectance which concerns on the front glass which comprises the 1st experimental ultraviolet irradiation device produced in Experimental example 1. FIG. It is a spectrum figure which concerns on the ultrahigh pressure mercury lamp as a short arc type discharge lamp which comprises the 1st experimental ultraviolet irradiation device produced in Experimental example 1. FIG. It is explanatory drawing which shows an example of a structure of the conventional ultraviolet irradiation device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Concave reflection mirror 11A Light projection port 13 Front glass 15 Short arc type discharge lamp 21 Discharge vessel 21A Light emission tube part 21B Sealing tube part 31 Light source lamp 32 Concave reflection mirror 32A Light projection port 33 Heat ray cut filter 41 Light source lamp 42 Concave reflection mirror 42A Light projection port 43 Heat ray cut filter 45 Shutter 46 Optical fiber unit 47 Lens unit

Claims (4)

A concave reflection mirror, a front glass provided in front of the light projection direction of the light projection port of the concave reflection mirror, and a short arc type discharge lamp in which mercury is enclosed, a short arc type discharge lamp, The concave reflecting mirror is substantially aligned with the center of the electrode of the short arc type discharge lamp, and the optical axis of the concave reflecting mirror is aligned with the arc axis of the short arc type discharge lamp. And
The concave reflecting mirror has a reflecting surface that reflects 80% or more of light in a wavelength region of 350 to 450 nm and reflects 50% or more of light in a wavelength region of 450 to 590 nm;
The ultraviolet irradiation apparatus, wherein the front glass has a transmittance of 50% or more for light in the entire region having a wavelength of at least 350 to 400 nm and reflects at least 50% of light in the region of a wavelength of 530 to 590 nm. A concave reflection mirror, a front glass provided in front of the light projection direction of the light projection port of the concave reflection mirror, and a short arc type discharge lamp in which mercury is enclosed, a short arc type discharge lamp, The concave reflecting mirror is substantially aligned with the center of the electrode of the short arc type discharge lamp, and the optical axis of the concave reflecting mirror is aligned with the arc axis of the short arc type discharge lamp. And
The concave reflecting mirror has a reflecting surface that reflects 80% or more of light in a wavelength region of 300 to 450 nm and reflects 50% or more of light in a wavelength region of 450 to 590 nm;
The ultraviolet irradiation device, wherein the front glass has a transmittance of 50% or more for light in the entire region having a wavelength of at least 300 to 400 nm and reflects at least 50% of light in the region of a wavelength of 530 to 590 nm.   The maximum value of the spectral reflectance in the wavelength region of light to be reflected at a specific ratio in each of the concave reflection mirror and the front glass is 95% or more. UV irradiation device. The ultraviolet irradiation device according to any one of claims 1 to 3, wherein the short arc type discharge lamp is filled with 0.08 mg / mm ³ or more of mercury.

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