JP2005235673A - Electric discharge panel with photocatalyst - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric discharge panel with a photocatalyst wherein a large surface area of the photocatalyst disposed on an exterior surface of a front substrate is secured. <P>SOLUTION: The bent front substrate 12 consisting of translucent material transmissive for ultraviolet rays and a planar rear substrate 14 consisting of insulative material are arranged to confront to each other with a predetermined gap and fringes of the substrates 12 and 14 are sealed via sealing material 16 to form a airtight container 18. Ultraviolet gas and a pair of electric discharge electrodes 20 and 20 are sealed in the airtight container 18. Further, a plurality of translucent porous suction material 24 formed by holding a photocatalyst consisting of anatase type titanium oxide (TiO<SB>2</SB>) or the like on an exterior surface of the front substrate 12 is adherently disposed via a translucent adhesive 26. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  According to the present invention, a front substrate and a rear substrate made of a translucent material are arranged to face each other with a predetermined gap therebetween, and an airtight container formed by sealing the peripheral edges of both substrates, and a discharge sealed in the airtight container The present invention relates to a discharge panel with a photocatalyst comprising a gas and a plurality of discharge electrodes, and a photocatalyst disposed on the outer surface of the front substrate, and in particular, with a photocatalyst capable of ensuring a large surface area of the photocatalyst disposed on the outer surface of the front substrate. It relates to a discharge panel.

Photocatalysts such as titanium oxide (TiO ₂ ) are activated when irradiated with ultraviolet rays and the like, causing a strong redox action, and harmful compounds such as nitrogen oxides (NO _X ) and sulfur oxides (SO _X ) and pollution. Attempts have been made to purify air and water by disposing this photocatalyst on the outer surface of the front substrate of the discharge panel because it exhibits the action of effectively decomposing things and the like.
By the way, decomposition of harmful compounds, pollutants and the like by the photocatalyst is an effect caused by contact of these harmful compounds and pollutants with the photocatalyst. Therefore, in order to improve the ability of the photocatalyst to purify air and water, it is desirable to increase the surface area of the photocatalyst as much as possible.

Therefore, the present applicant first applies a large number of fibrous bodies whose surfaces are coated with a photocatalyst to the outer surface of the front substrate constituting the discharge panel in a standing state with respect to the outer surface of the air front substrate. Proposed a discharge panel with a photocatalyst (Japanese Patent Laid-Open No. 2003-346714).
As shown in FIG. 7, this photocatalyst-equipped discharge panel 70 includes a curved plate-like front substrate 72 made of an insulating ultraviolet transmitting material and a flat plate-like rear substrate 74 made of an insulating material with a predetermined gap. The airtight container 78 is formed by airtightly sealing the peripheral edges of both substrates 72 and 74 via a sealing material 76 and filling the airtight container 78 with an ultraviolet radiation gas.
In addition, a pair of strip-like discharge electrodes 80, 80 are arranged on the inner surface of the rear substrate 74 with a predetermined gap therebetween.
Furthermore, an ultraviolet wavelength converting phosphor layer 82 is formed on the inner surface of the front substrate 72.

On the outer surface of the front substrate 72, a large number of fibrous bodies 86 whose surfaces are coated with a photocatalyst 84 made of anatase-type titanium oxide (TiO ₂ ) are attached to the outer surface of the front substrate 72 via an adhesive 88. It is attached in a vertically standing state. The fibrous body 86 is configured by coating the surface of a fiber 90 such as glass fiber or resin fiber with a photocatalyst 84 (FIGS. 8 and 9).

In the discharge panel 70 with a photocatalyst, when a discharge is generated between the pair of discharge electrodes 80, 80, electrons collide with the ultraviolet radiation gas to generate ultraviolet rays having various wavelengths. The generated ultraviolet rays are irradiated onto the phosphor layer 82 to be converted into ultraviolet rays (300 to 400 nm) having a wavelength particularly suitable for activation of the photocatalyst 84, and then transmitted through the front substrate 72 to the photocatalyst 84. Irradiated. As a result, the photocatalyst 84 is activated and air or water can be purified.
JP 2003-346714 A

In the discharge panel 70 with the photocatalyst, the front substrate 72 has a curved plate shape, and the outer surface of the front substrate 72 has a curved surface. Therefore, compared to the case where the outer surface of the front substrate 72 is a flat surface, The surface area of the outer surface of the substrate 72 can be increased, and the surface area of the photocatalyst 84 disposed on the outer surface of the front substrate 72 can be increased accordingly.
Further, in the discharge panel 70 with the photocatalyst, a large number of fibrous bodies 86 covered with the photocatalyst 84 are attached in a standing state substantially perpendicular to the outer surface of the front substrate 72. The surface area of the outer surface increases the surface integral of the many fibrous bodies 86 attached, and as a result, the surface area of the photocatalyst 84 disposed on the outer surface of the front substrate 72 can be dramatically increased.
However, since it is desirable to increase the surface area of the photocatalyst as much as possible in order to improve the ability of the photocatalyst to purify air and water, the photocatalyst-equipped discharge panel can further secure the surface area of the photocatalyst disposed on the outer surface of the front substrate. The appearance of was desired.

  The present invention has been made to meet the above-described demand, and an object of the present invention is to realize a discharge panel with a photocatalyst that can secure a large surface area of the photocatalyst disposed on the outer surface of the front substrate.

  In order to achieve the above object, a discharge panel with a photocatalyst according to the present invention includes a front substrate made of a light-transmitting material and a rear substrate disposed opposite to each other with a predetermined gap therebetween, and the periphery of both substrates is sealed. A discharge panel with a photocatalyst formed by forming an airtight container, enclosing a discharge gas in the airtight container, disposing a plurality of discharge electrodes inside or outside the airtight container, and disposing a photocatalyst on the outer surface of the front substrate. The outer surface of the front substrate is a curved surface, and a large number of light-transmitting porous adsorbents are disposed on the outer surface of the front substrate, and a photocatalyst is disposed on the surface and pores of the porous adsorbent. It is characterized by being held.

  The porous adsorbent is fixed to the outer surface of the front substrate via a light-transmitting adhesive, for example. In addition, the porous adsorbent may be disposed on the outer surface of the front substrate, and the porous adsorbent may be covered with a net-like member.

  It is desirable to arrange a reflective material together with the porous adsorbent on the outer surface of the front substrate.

In the discharge panel with a photocatalyst of the present invention, a large number of porous adsorbents having an extremely large specific surface area are arranged on the outer surface of the front substrate, and the photocatalyst is held on the surfaces and pores of these porous adsorbents. Therefore, a large surface area of the photocatalyst disposed on the outer surface of the front substrate can be ensured.
Further, in the discharge panel with a photocatalyst of the present invention, the front substrate has a curved plate shape, and the outer surface of the front substrate has a curved surface. Therefore, compared to the case where the outer surface of the front substrate is a flat surface, The surface area can be increased, and the surface area of the photocatalyst disposed on the outer surface of the front substrate can be increased accordingly.

  In addition, when a reflective material is arrange | positioned with the said porous adsorption material on the outer surface of a front substrate, the light which activates a photocatalyst can be reflected in various directions, and the irradiation efficiency to a photocatalyst can be improved.

Hereinafter, an embodiment of a discharge panel with a photocatalyst according to the present invention will be described based on the drawings.
1 and 2 show a first discharge panel 10 with a photocatalyst according to the present invention. The first discharge panel 10 with a photocatalyst is made of a translucent insulating material that transmits ultraviolet rays, such as quartz glass. A curved plate-like front substrate 12 and a flat plate-like rear substrate 14 made of an insulating material such as glass are arranged to face each other with a predetermined gap therebetween, and the periphery of both the substrates 12 and 14 is sealed with low melting glass or the like. An airtight container 18 is formed by sealing hermetically through the adhering material 16, and a rare gas such as argon or xenon or a mixed gas and mercury are mixed in the airtight container 18 as a discharge gas. Filled with ultraviolet radiation gas or ultraviolet radiation gas mainly composed of xenon.

A pair of strip-like discharge electrodes 20 and 20 are disposed on the inner surface of the rear substrate 14 so as to face each other with a predetermined gap. In addition, one end of each of the discharge electrodes 20 and 20 penetrates the sealing material 16 and is led out of the hermetic container 18. The discharge electrode 20 can be made of 42-6 alloy, Fe-Ni alloy, or the like.
Furthermore, an ultraviolet wavelength converting phosphor layer 22 described later is formed on the inner surface of the front substrate 12.
As described above, since the front substrate 12 has a curved plate shape, the outer surface of the front substrate 12 is a curved surface.

The phosphor layer 22 has a wavelength of less than 300 nm, which is particularly suitable for activating the photocatalyst, among various wavelengths of ultraviolet light emitted from the ultraviolet radiation gas by the discharge between the discharge electrodes 20 and 20. It is provided for conversion to ultraviolet light having a wavelength of 400 nm.
The phosphor layer 22 includes, for example, (CaZn) ₃ (PO ₄ ) ₂ : Tl, Ca ₃ (PO ₄ ) ₂ : Tl, SrB ₄ O ₇ : Eu, (Ba, Sr, Mg) ₃ Si ₂ O _7. : Pb, BaSi ₂ O ₅ : Pb, YPO ₄ : Ce, Ce (Mg, Ba) Al ₁₁ O ₁₉ , LaPO ₄ : Ce, and the like.
Thus, by providing the phosphor layer 22, the wavelength (wavelength of less than 300 nm) that does not contribute much to the activation of the photocatalyst among the ultraviolet rays of various wavelengths emitted from the ultraviolet radiation gas and irradiated on the photocatalyst. ) Is converted into ultraviolet light (300 to 400 nm) having a wavelength particularly suitable for the activation of the photocatalyst, so that the activation of the photocatalyst can be promoted.

A large number of light-transmitting porous adsorbents 24 holding a photocatalyst (not shown) made of anatase-type titanium oxide (TiO ₂ ) or the like are provided on the outer surface of the front substrate 12 so that the light-transmitting adhesive is present. It is fixedly arranged via the agent 26.
The translucent adhesive 26 is, for example, an alkali silane bond, an ethyl silicate bond, an alkoxy lane bond, an alkoxy lane bond in which an organic functional group is partially introduced, and an alkoxy lane bond obtained by reacting an organic polymer. An inorganic binder such as a product or a hybrid inorganic binder can be used.

The translucent porous adsorbent 24 is composed of bead-shaped silica gel having a diameter of about 0.1 mm to 5 mm having a large number of pores having a diameter of about 10 nm to 50 nm, and the specific surface area of the pores is 50 m ^2. / G to about 300 m ² / g. The photocatalyst is adsorbed and held not only on the surface of the porous adsorbent 24 but also in the pores.
In order to hold the photocatalyst on the surface and pores of the porous adsorbent 24, for example, the porous adsorbent 24 is immersed in a dispersion of photocatalyst fine particles whose particle diameter is smaller than the pore diameter of the porous adsorbent 24. Then, it can be performed by drying and firing.

  In the first discharge panel with a photocatalyst 10, when a discharge is generated between the pair of discharge electrodes 20, 20, electrons collide with the ultraviolet radiation gas to generate ultraviolet rays having various wavelengths. The generated ultraviolet rays are irradiated onto the phosphor layer 22 to be converted into ultraviolet rays (300 to 400 nm) having a wavelength particularly suitable for activating the photocatalyst, and then transmitted through the front substrate 12 to be porous adsorbed. The photocatalyst held on the material 24 is irradiated. As a result, the photocatalyst is activated and air and water can be purified.

Thus, in the first photocatalyst-equipped discharge panel 10, a large number of porous adsorbents 24 having a very large specific surface area are arranged on the outer surface of the front substrate 12, and the surface of the porous adsorbents 24 and Since the photocatalyst is held in the pores, a large surface area of the photocatalyst disposed on the outer surface of the front substrate 12 can be secured.
In addition, the first discharge panel 10 with a photocatalyst has a front plate 12 having a curved plate shape, and the outer surface of the front substrate 12 has a curved surface. The surface area of the outer surface of the substrate 12 can be increased, and the surface area of the photocatalyst disposed on the outer surface of the front substrate 12 can be increased accordingly.
As described above, since the porous adsorbent 24 and the adhesive 26 have translucency, the surface of the porous adsorbent 24 and the photocatalyst held in the pores can be sufficiently irradiated with light. It is. Further, since the porous adsorbent 24 having a large number of pores is excellent in air permeability and water permeability, the contact efficiency between the photocatalyst and air or water is good.
In the first discharge panel 10 with a photocatalyst, the porous adsorbent 24 is directly disposed on the outer surface of the front substrate 12, so that the photocatalyst is hardly attenuated with the light output of the ultraviolet light transmitted through the front substrate 12. The activation efficiency of the photocatalyst is high.

FIG. 3 shows a modified example of the first photocatalyst-equipped discharge panel 10. The modified example of the first photocatalyst-equipped discharge panel 10 includes a large number of porous adsorbents 24 on the outer surface of the front substrate 12. A plurality of bead-like reflectors 28 are fixedly arranged via a translucent adhesive 26.
The reflector 28 can be made of a material having a high light reflectance such as aluminum. Further, the reflecting material 28 may be formed of a member whose surface is white with high light reflectance.
Thus, by using the reflective material 28 together with the porous adsorbent material 24, it is possible to reflect the ultraviolet rays that activate the photocatalyst in various directions and improve the irradiation efficiency of the photocatalyst.

  FIG. 4 shows a second discharge panel 30 with a photocatalyst according to the present invention. The second photocatalyst-equipped discharge panel 30 uses, as the back substrate 32, a curved plate made of a light-transmitting insulating material that transmits ultraviolet light, such as quartz glass, like the front substrate 12. A large number of translucent porous adsorbents 24 each holding a photocatalyst are fixedly disposed on the outer surface of the substrate with a translucent adhesive 26, and the inner surface of the back substrate 32 on which the discharge electrode 20 is formed. Further, it is characterized in that the phosphor layer 22 for ultraviolet wavelength conversion is formed.

  In the second discharge panel 30 with a photocatalyst, a large number of porous adsorbents 24 holding the photocatalyst are disposed not only on the outer surface of the front substrate 12 but also on the outer surface of the rear substrate 32. The air and water can be purified by the photocatalyst on both surfaces of the panel (the outer surface of the front substrate 12 and the outer surface of the rear substrate 32).

FIG. 5 shows a third discharge panel 34 with a photocatalyst according to the present invention. In the third photocatalyst-equipped discharge panel 34, a large number of porous adsorbents 24 are arranged on the outer surface of the front substrate 12, and the porous adsorbents 24 are connected by a mesh member 38 having a large number of communication holes 36. It is configured by coating. The mesh member 38 can be made of an appropriate material such as metal or resin. However, when the mesh member 38 is made of a conductive material, the insulation between the pair of discharge electrodes 20 and 20 is impaired. It is necessary to be careful not to.
Even in this third photocatalyst-equipped discharge panel 34, a large number of porous adsorbents 24 having a very large specific surface area are arranged on the outer surface of the front substrate 12, and the surfaces and pores of these porous adsorbents 24 are arranged. Since the photocatalyst is held, a large surface area of the photocatalyst disposed on the outer surface of the front substrate 12 can be secured.

FIG. 6 shows a modified example of the third photocatalyst-equipped discharge panel 34. The modified example of the third photocatalyst-equipped discharge panel 34 has a large number of porous adsorbents 24 on the outer surface of the front substrate 12. FIG. A plurality of reflectors 28 are arranged, and the porous adsorbent 24 and the reflector 28 are covered with a mesh member 38.
Thus, by using the reflective material 28 together with the porous adsorbent material 24, it is possible to reflect the ultraviolet rays that activate the photocatalyst in various directions and improve the irradiation efficiency of the photocatalyst.

  In order to increase the surface area of the photocatalyst, the net member 38 may carry the photocatalyst.

As the photocatalyst, other metal oxides having photocatalytic action such as ZnO, SrTiO ₃ , BaTiO ₃ , Fe ₂ O _{3 and the} like can be used in addition to the above titanium oxide, but anatase type titanium oxide is a photocatalyst. It is excellent in activity and can be used most preferably.
The photocatalyst can be not only a photocatalyst that is activated by irradiation with ultraviolet rays but also a visible light photocatalyst that is activated by irradiation with visible light. In this case, the front substrate 12 of the first photocatalyst discharge panel 10, the front substrate 12 and the rear substrate 32 of the second photocatalyst discharge panel 30, and the front substrate 12 of the third photocatalyst discharge panel 34 are visible light. The gas-tight container 18 is filled with a discharge gas that emits visible light having a wavelength that activates the visible light photocatalyst. Also, the phosphor layer 22 for ultraviolet wavelength conversion is not necessary.

  In the above description, the case where the translucent porous adsorbent 24 is made of silica gel has been described as an example. However, the present invention is not limited to this, and a large number of fine units of nm such as Vycor glass are used. The porous adsorbent 24 may be composed of porous glass having pores.

  Further, in the above description, the case where the porous adsorbent 24 is directly disposed on the outer surface of the front substrate 12 and the rear substrate 32 has been described as an example, but between the outer surface of the front substrate 12 and the porous adsorbent 24 is described. The outer surface of the back substrate 32 and the porous adsorbent 24 may be arranged with a slight gap between them. In this case, in order to prevent attenuation of the light output of the ultraviolet rays transmitted through the front substrate 12 and the rear substrate 32, the interval is preferably 10 mm or less.

When the discharge panel with photocatalyst 10, 30, 34 of the present invention is used for purifying a gas such as air, the surface of the porous adsorbent 24 is made of a silicon resin or a polymer of tetrafluoroethylene. You may coat | cover with water-repellent gas-permeable resin, such as Teflon (trademark) which is (polytetrafluoroethylene, PTFE).
As described above, when the surface of the porous adsorbent 24 is coated with a water-repellent gas-permeable resin, the porous adsorbent 24 is suppressed from adsorbing moisture in the air into the pores. The target gas can be efficiently adsorbed in the pores and brought into contact with the photocatalyst in the pores.
In the case of the first photocatalyst-equipped discharge panel 10 and the second photocatalyst-equipped discharge panel 30, a water-repellent gas-permeable resin such as silicon resin or Teflon (registered trademark) is used as a translucent adhesive. A large number of light-transmitting porous adsorbents 24 may be fixed to the outer surfaces of the front substrate 12 and the rear substrate 32. Also in this case, the water-repellent gas-permeable resin used as the adhesive 26 suppresses the porous adsorbent 24 from adsorbing moisture in the air into the pores, and as a result, the gas to be purified Can be efficiently adsorbed in the pores and brought into contact with the photocatalyst in the pores.

  Further, in the above, the DC drive type discharge panel in which the pair of discharge electrodes 20 and 20 are formed inside the hermetic vessel 18 is illustrated, but the present invention is an AC that arranges a pair of discharge electrodes outside the hermetic vessel. The present invention is also applicable to a drive type discharge panel and an AC drive type discharge panel in which one discharge electrode is arranged inside the hermetic vessel and the other discharge electrode is arranged outside the hermetic vessel.

It is a schematic sectional drawing which shows typically the 1st discharge panel with a photocatalyst concerning this invention. It is AA fragmentary sectional drawing of FIG. It is a schematic sectional drawing which shows typically the modification of the 1st discharge panel with a photocatalyst. It is a schematic sectional drawing which shows typically the 2nd discharge panel with a photocatalyst concerning this invention. It is a front view which shows typically the 3rd discharge panel with a photocatalyst concerning this invention. It is a front view which shows typically the modification of the 3rd discharge panel with a photocatalyst. It is sectional drawing which shows the conventional discharge panel with a photocatalyst. It is an expanded longitudinal cross-sectional view of the fibrous body in the conventional discharge panel with a photocatalyst. It is an expanded cross-sectional view of the fibrous body in the conventional discharge panel with a photocatalyst.

Explanation of symbols

10 First discharge panel with photocatalyst
12 Front board
14 Back board
18 Airtight container
20 Discharge electrode
22 Phosphor layer
24 Porous adsorbent
26 Translucent adhesive
28 Reflector
30 Second discharge panel with photocatalyst
32 Back board
34 Discharge panel with third photocatalyst
38 Mesh member

Claims (4)

  A front substrate and a rear substrate made of a light-transmitting material are arranged to face each other with a predetermined gap therebetween, and the periphery of both substrates is sealed to form an airtight container, and a discharge gas is sealed in the airtight container. A discharge panel with a photocatalyst, wherein a plurality of discharge electrodes are arranged inside or outside an airtight container and a photocatalyst is arranged on the outer surface of the front substrate, wherein the outer surface of the front substrate is a curved surface, A discharge panel with a photocatalyst, wherein a large number of light-transmitting porous adsorbents are arranged on the outer surface of the electrode, and a photocatalyst is held on the surface and pores of the porous adsorbent.   2. The discharge panel with a photocatalyst according to claim 1, wherein the porous adsorbent is fixed to the outer surface of the front substrate through a translucent adhesive.   The discharge panel with a photocatalyst according to claim 1, wherein the porous adsorbent is disposed on an outer surface of the front substrate, and the porous adsorbent is covered with a mesh member. The discharge panel with a photocatalyst according to any one of claims 1 to 3, wherein a reflector is disposed together with the porous adsorbent on the outer surface of the front substrate.

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