US20010007507A1

US20010007507A1 - Photocatalytic panel and method for activating same

Info

Publication number: US20010007507A1
Application number: US09/770,933
Authority: US
Inventors: Keiji Iimura
Original assignee: Individual
Current assignee: Individual
Priority date: 1996-02-27
Filing date: 2001-01-24
Publication date: 2001-07-12
Also published as: US6238630B1

Abstract

A photocatalytic panel or pane and a method for activating the same are disclosed. The photocatalytic panel includes a transparent substrate having major surfaces parallel with and opposed to each other and an edge surface; a photocatalytic film formed on at least one of the major surfaces and a light source for exciting the photocatalytic film. Light from the light source enters the substrate from a vicinity of the edge surface (or a peripheral portion of the substrate) and then is reflected totally within a laminate of the substrate and the photocatalytic film. The method includes the steps: preparing the photocatalytic panel, entering light from the light source into the substrate from a vicinity of the edge surface (or the peripheral portion and reflecting the light within the laminate in accordance with total internal reflection, thereby the photocatalytic film is excited. Therefore, the photocatalytic film can effectively be activated via the substrate to oxidize/reduce substances in contact with the photocatalytic film.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a divisional application of my U.S. patent application Ser. No. 09/146,917 filed on Sep. 2, 1998, now U.S. Pat. No. XX issued on YY, 2001. [0001]

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photocatalytic panel (or pane) and a method for activating or exciting a photocatalytic layer (i.e. film) of the photocatalytic panel by photo catalyzing.

2. Description of Related Art

It is well known that a photocatalyst activating by light rays with relatively short wavelength decomposes or dissolves organic substances which are in contact with, in close vicinity to, or deposited on the photocatalyst by reaction of oxidation and/or reduction or photocatalyst effect.

Typical photocatalyst is a kind of photo-activated semiconductor such as Titanium Dioxide (TiO ₂)

There are many fields of application of such photocatalyst, for instance, cleaning to delete dirty component from the surface of articles, dirt protection to prevent depositing of dirty component, prevention from spread of infection, deleting of odor, cleaning of air, processing of exhausting gas, cleaning of water, processing of exhausting water, dissolving of water to make Hydrogen, speeding up of a chemical reaction and dissolving of pollutant which causes social pollution.

All the applications as mentioned in the above utilize the photocatalyst reaction or photocatalyst function by strong oxidation/reduction power to exert when the photocatalyst is activated by light.

For example, the photocatalyst or photocatalytic material being irradiated by the light rays with short wavelength activates any Oxygen (02) existing in the air that dissolved or mixed in water, in order to form Ozone (03) or activated Oxygen (0). The Ozone or the activated Oxygen decomposes microorganisms such as fungi (i.e. molds) or bacteria and organic chlorine compound containing in the water by oxidization. Therefore, the odor-less or color-less water is obtained and the water is sterilized.

Furthermore, the photocatalyst being irradiated by the light rays having short wavelength shows a high activity of decomposition of water and helps to decompose the water (H ₂O) to activated oxygen (0) and hydrogen (H₂).

Moreover, the photocatalyst as the material or substance for eliminating or decreasing environmental pollution, contributes to the decomposition of pollutants, in which the pollutants contain a volatile organic solvent such as trichroloethylene, tetrachroloethylene, a chemical agent for agriculture such as grass eliminating agent bioinsecticide, an organic phosphate and a harmful inorganic chemical compound such as cyan and a kind of chrome.

Where multiple photocatalyst particles are used directly for reaction of oxidation-reduction with any substance, it is very difficult to separate and collect the photocatalyst particles, and a device to utilize photocatalyst particles becomes complicated and large scale.

While, where multiple photocatalyst particles are used as a form of photocatalyst supported substrate, in which a layer including the photocatalyst particles is fixed and supported on the substrate, recycling of the photocatalyst particles can be easily done because the separation and collection of the photocatalyst particles are not needed.

As for the latter case using the photocatalyst supported substrate, Japanese Patent application Laid-open No. Hei-05-155726 (published on Jun. 22, 1993) discloses that a Titanium Dioxide layer of photocatalyst is coated on a substrate such as metal, ceramic and glass, for the purpose of protecting a surface of the substrate from growth of bacteria.

Referring to FIG. 5 and FIG. 6, a typical prior art showing a device including photocatalyst (a substrate device supporting photocatalyst, a device with photocatalyst, or a photocatalyst device) is explained, in which a layer including photocatalyst particles is fixed on a substrate.

FIG. 5 illustrates a schematic perspective view of a photocatalyst reactor showing the prior art and FIG. 6 illustrates a schematic enlarged cross-sectional view taken along the line B-B in FIG. 5, showing the

photocatalyst device

300.

In FIG. 5 and FIG. 6, the

photocatalyst device

300 consists of a plate like a substrate 30 made from metal, ceramic or glass and a photocatalyst layer 20 made of a binder layer including many photocatalyst particles in which the photocatalyst layer 20 is formed or fixed on the substrate 30.

As shown in FIG. 5, a conventional photocatalyst reactor consists of the

photocatalyst device

300 having the substrate 30 and the photocatalyst layer 20 and a short wavelength light source 210 generating short wavelength light rays, such as Ultraviolet (UV) light rays. The light source 210 is preferably composed of a lamp having a linear shape (i.e. a tubular shape).

The short

wavelength light source

210 is installed at a location, distant from the photocatalyst layer 20 of photocatalyst device 300, keeping a vertical distance

As shown in FIG. 5 and 6, the UV light rays L10 generating from the Ultraviolet light source 210 are directed toward a front surface of the substrate 30 and irradiate directly a front surface of photocatalyst layer 20 coated on the front surface of the substrate 30.

Reference mark “OB” indicating as circle in FIG. 5 shows an object to be cleaned-up or purified, or a dirty component such as dirty substance by foods, molds, bacteria, dirty substance by oil, which is in contact with, in close vicinity to, or deposited on the

photocatalyst layer

20.

In an area which the dirty object “OB⇄ exists, a large amount of the UV light rays L 10 is absorbed (or reflected) at the dirty object “OB”, on the way passing through the dirty object “OB”. Therefore, only a small amount of the light rays L10 reaches to the photocatalyst layer 20 in the area and the photocatalyst layer 20 in the area is activated or energized by the UV light rays L10 with reduced lighting power.

Further, where the object “OB” composed of various media such as liquid (water, etc.) or gas (exhaust gas, etc.) are cleaned-up or processed to react for clarification, the object “OB” exists between the

UV light source

210 and the photocatalyst device 300. In this case, the object “OB” absorbs (or reflects) some amount of the UV light rays L10 irradiated from the UV light source 210 and the photocatalyst layer 20 of the photocatalyst device 300 receives the remaining amount of UV light rays L10. Therefore, only the remaining amount of UV light rays L10 activates the photocatalyst layer 20.

As well known, water (generally liquid) can easily transmit visible light rays, while it absorbs short wavelength light rays L 10 such as UV rays instead of transmitting.

Accordingly, in the prior art, an efficiency of short wavelength light rays L 10 used for activation of photocatalyst is too low, because the object “OB” exists between the short wavelength light source 210 and the photocatalyst layer 20 of the photocatalyst device 300.

Therefore, the prior art has such disadvantage that an effective use is not made for the short wavelength light rays L 10 irradiating (emitting) from the short wavelength light source 210 and a large volume of the short wavelength light source 210 with high power is required to accelerate a photocatalyst reaction in the

photocatalyst reactor

300 and 210.

SUMMARY OF THE INVENTION

A main object of the invention is to provide a new method for activating photocatalyst, new device and reactor including photocatalyst.

It is therefore an object of the present invention to provide a photocatalytic panel (i.e. photocatalytic pane or plate) for activating a photocatalytic layer (i.e. film) on a transparent substrate by light from a light source.

According to a first aspect of the present invention, there is provided a photocatalytic panel comprising a substantially transparent substrate having (1) first and second major surfaces that are substantially parallel with and opposed to each other and (2) an edge surface that connects the first and second major surfaces together; a photocatalytic film formed on at least one of the first and second major surfaces; and a light source for exiting (or activating) the photocatalytic film, the light source being disposed at a position relative to a laminate of the transparent substrate and the photocatalytic film (i.e. layer) such that light from the light source enters the transparent substrate from the edge surface and then the light is reflected totally within the laminate, thereby to excite the photocatalytic film.

According to a second aspect of the present invention, there is provided a photocatalytic panel comprising: a substantially transparent substrate having a first and second major surfaces that are substantially parallel with and opposed to each other; a photocatalytic film formed on the first and second major surfaces; and a light source for exiting the photocatalytic film, the light source being disposed at a position relative to a laminate of the transparent substrate and the photocatalytic film such that light from the light source enters the transparent substrate from a vicinity of a terminal portion of the first or second major surface, thereby to reflect the light totally within the laminate to excite the photocatalytic film.

According to a third aspect of the present invention, there is provided a method for activating a photocatalytic panel comprising the steps: preparing a photocatalytic transparent panel composed of (1) a substantially transparent substrate having first and second major surfaces that are substantially parallel with and opposed to each other and an edge surface that connects the first and second major surfaces together, (2) a photocatalytic film formed on at least one of the first and second major surfaces; and (3) a light source for exiting the photocatalytic film, the light source being disposed at a position relative to a laminate of the transparent substrate and the photocatalytic film; entering light from the light source into the transparent substrate from the edge surface or a vicinity of a terminal portion of the first or second major surface, and reflecting the light within the laminate in accordance with the principles of total internal reflection, thereby the photocatalytic film is excited.

In these aspects of the present invention, the photocatalytic film (or layer) supported on the transparent substrate is not required to exist or present between object/objects to be cleaned or be processed to make clean-up and a light source emitting short wavelength light to activate the photocatalyst film or layer, because the photocatalytic film can be directly excited or activated by light from the light source, in which the light totally reflect repeatedly within the laminate.

The object to be cleaned, or reacted, etc. which is contacted, closed to, or stacked can be cleaned-up or processed to react for clarification by photo-catalyzing

As compared with the prior art as explained with FIG. 5 and FIG. 6, any objects (substances) to be cleaned or reacted, etc. are not existed between the surface/surfaces of the photocatalytic film (layer) and the light source, in the present invention.

Therefore, the present invention has a high efficiency of utilization of the light for activating (or exiting) the photocatalytic film, in which a large amount of the light can be utilized for activating the photocatalytic film effectively without loss or with a minimum loss. Furthermore, the present invention can use the light source with a power smaller than the light source in the prior art.”

BRIEF DESCRIPTION OF THE DRAWINGS

A complete understanding of this invention may be obtained from the following explanations, in connection with the accompanying drawings; in which: [0036]
FIG. 1 illustrates a schematic perspective view of a photocatalyst reactor, explaining a basic preferred embodiment of the present invention; [0037]
FIG. 2 illustrates a partially omitted, schematic enlarged cross-sectional view taken along the line A-A in FIG. 1, showing the [0038] photocatalyst device 100;
FIG. 3 shows a schematic enlarged cross- sectional view, taken along the line A-A of FIG. 1, in which scale of FIG. 3 is different from FIG. 1 and FIG. 2; [0039]
FIG. 4 shows a schematic enlarged cross- sectional view, enlarging a [0040] part 100 a in FIG. 3.
FIG. 5 illustrates a schematic perspective view of a photocatalyst reactor showing the prior art. [0041]
FIG. 6 illustrates a schematic enlarged cross-sectional view taken along the line B-B in FIG. 5, showing the [0042] photocatalyst device 300;
FIG. 7 illustrates a schematic perspective view explaining another embodiment of the invention; [0043]
FIG. 8 illustrates a schematic enlarged cross-sectional view explaining still another embodiment of the invention; [0044]
FIG. 9 illustrates a schematic enlarged cross-sectional view explaining other embodiment of the invention; [0045]
FIG. 10 illustrates a schematic enlarged cross-sectional view explaining further embodiment of the invention; [0046]
FIG. 11 illustrates a schematic enlarged cross-sectional view explaining still further more embodiment of the invention; [0047]
FIG. 12 illustrates a schematic enlarged cross-sectional view explaining further embodiment of the invention; [0048]
FIG. 13 illustrates a schematic enlarged cross-sectional view explaining further embodiment of the invention; [0049]
FIG. 14 illustrates a schematic enlarged cross-sectional view explaining further embodiment of the invention; and [0050]
FIG. 15 illustrates a schematic enlarged cross-sectional view explaining further embodiment of the invention. [0051]

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described in detail with reference to the accompanying drawings. [0052]
Like reference characters designate like or corresponding parts or portions throughout the drawings. [0053]
Reference is made to FIG. 1 and FIG. 2 showing one preferred basic embodiment of this invention. [0054]
FIG. 1 illustrates a schematic perspective view of a photocatalyst reactor and FIG. 2 illustrates a partially omitted, schematic enlarged cross-sectional view taken along the line A-A in FIG. 1, showing a [0055] photocatalyst device 100.
In FIG. 1 and FIG. 2, the photocatalyst device [0056] 100 (i.e. photocatalytic panel or pane) composes a panel like light transmission member or a light transmission panel 10 (i.e. transparent substrate), which can transmit well short wavelength rays L1 and a photocatalyst layer 20 (i.e. photocatalytic film) including photocatalyst, in which the photocatalyst layer 20 (photocatalytic film) is supported on a front surface 10 a (i.e. a first major surface) of the light transmission panel 10 (i.e. transparent substrate).
[0057] Numeral 10 b denotes a rear surface (i.e. a second major surface), numeral 1Oc denotes a side terminal surface (i.e. an end surface, or a first end surface), numeral 10 d denotes another side terminal surface 10 d (a second end surface) in the light transmission panel 10 (i.e. transparent substrate) and reference character “OB” denotes the object to be cleaned, or reacted, etc.
In more detail, as illustrated clearly in FIG. 1 and FIG. 2, the “photocatalytic panel” [0058] 100 (such as “photocatalytic glass panel ”) comprises the substantially “transparent substrate” 10 (such as “glass substrate”) having the “first major surface”(i.e. “front surface” 10 a) and the “second major surface” (i.e. “rear surface” 10 b) that are substantially parallel with and opposed to each other and the “first edge surface” (i.e. “a side surface” 10 c) that connects the first and second major surfaces (i.e. the front surface 10 a and the rear surface 10 b) together; the photocatalytic film (i.e. photocatalyst layer 20) formed on the first major surface (i.e. front surface 10 a); and a light source 200 for exiting or activating the photocatalytic film (i.e. photocatalyst layer 20), the light source 200 being disposed at a position relative to a laminate of the transparent substrate 10 (such as glass substrate) and the photocatalytic film (i.e. photocatalyst layer 20) such that light from the light source 200 enters the transparent substrate 10 (such as glass substrate) from the first edge surface (i.e. side surface 10 c) and then the light is reflected totally within the laminate (the numeral 10 and 20), thereby to excite the photocatalytic film (i.e. photocatalyst layer 20).
At this time, an ultraviolet region of the light can be prevented from escaping from the first and second major surfaces, since the photocatalytic film absorbs the ultraviolet region of the light and the photocatalytic film is excited by the light. [0059]
The [0060] edge surface 10 c (or 10 d) of the transparent substrate 10 is substantially perpendicularly to each of the first and second surfaces 10 a and 10 b of the transparent substrate 10, which is clearly shown in FIG. 1 and FIG. 2.
The [0061] light transmission panel 10 may be made of an inorganic material or glass material such as Fused Quartz (including not less than 99.9 weight % of SiO₂), Sapphire, Borosilicate glass (composing SiO₂; 75.3, B ₂ 0 ₃; 13.8; ZnO; 1.4, Al ₂ 0 ₃; 4.3, NaO; 5.0 weight %), etc. and it may be made of an organic material or a plastic or polymer material such as Silicone resin such as Dimethyl Silicone, Acrylic resin such as Methacrylate, Polyethylene, Polycarbonate resin and UV transmissible Fluoric resin such as Polyfluoroethylene, etc.
The [0062] photocatalyst layer 20 includes a photocatalyst material, which is a kind of photo-activated semiconductor selected from Titanium Dioxide (i.e. Titania), Tungsten Oxide, Zinc Oxide, Tin Oxide and Zinc Sulfide. The photocatalyst layer 20 may be composed of multiple photocatalyst particles and an organic or inorganic binder to bind and fix the photocatalyst particles on the light transmission panel 10. A photocatalyst adding special metal such as Titanium Dioxide with a small amount of platinum has an excellent photocatalyst function.
In more detail, the [0063] photocatalyst layer 20 may be composed of multiple photocatalyst particles and a transparent organic binder or paint made of plastic material capable of transmitting the short wavelength rays L1 such as such as Silicone resin, Acrylic resin, Polycarbonate resin and UV transmissible Fluoric resin, Polyester resin etc.
Alternatively, the [0064] photocatalyst layer 20 may be composed of multiple photocatalyst particles and the transparent inorganic binder made of glass material capable of transmitting the short wavelength rays L1 such as glass frit (i.e. powders or particles).
Alternatively, the [0065] photocatalyst layer 20 may be made from Titanic sol, which is in advance coated on the inorganic light transmission panel 10, is treated by high temperature of about 500°C. then the Titania sol changes to Titanium Dioxide .
As shown in FIG. 1, a linear or tubular short wavelength [0066] light source 200 is placed at a vicinity of one side terminal surface 10 c of the light transmission panel 10 in order to irradiate or emit the short wavelength rays L1, which is introduced or input into the light transmission panel 10.
As shown in FIG. 1 and FIG. 2, the short wavelength rays L[0067] 1 (indicated as an arrow), irradiating from the short wavelength light source 200 are introduced into the light transmission panel 10, the short wavelength rays L2 (indicating as another arrow) once input into light transmission panel 10 repeat multiple reflection, total internal reflection (TIR) or total reflection, according to similar principle to an optical fiber, which is widely used for an optical telecommunication. The short wavelength rays L2 transmitting from the side terminal 10 c toward the another side terminal 10 d are simultaneously leaked out little by little or gradually to the front surface 10 a and the rear surface 10 b of the light transmission panel 10.
As shown in FIG. 1 and FIG. 2, the short wavelength rays L[0068] 1 (indicated as an arrow), irradiating from the short wavelength light source 200 are introduced into the light transmission panel 10, the short wavelength rays L2 (indicating as another arrow) once input into light transmission panel 10 repeat multiple reflection, total internal reflection (TIR) or total reflection, according to similar principle to an optical fiber which is widely used for an optical telecommunication. The short wavelength rays L2 transmitting from the side terminal 10 c toward the another side terminal 10 d are simultaneously leaked out little by little or gradually to the front surface 1Oa and the rear surface 10 b of the light transmission panel 10.
The short wavelength rays L[0069] 2 leaking from the front surface 1Oa are incident and are irradiating the photocatalyst layer 20 from a rear side. The photocatalyst layer 20 irradiating by the short wavelength rays L2 absorbs the short wavelength rays L2 and is activated.
Reference mark “OB” shows an object to be cleaned-up or purified, or a dirty component such as dirty substance by foods, molds, bacteria, dirty substance by oil, which exists on, is in contact with, or is deposited on the [0070] photocatalyst layer 20.
The [0071] photocatalyst layer 20 activated by the short wavelength rays L2 is letting the object “OB” indicated as a circle in FIG. 1 to dissolve and react by oxidation and/or reduction. Therefore, the photocatalyst device 100 and the photocatalyst reactor (composed of the photocatalyst device 100 and the short wavelength light source 200) are, for instance, capable of easily deleting the object “OB” from the surface of the photocatalyst layer 20, capable of sterilizing bacteria and virus, capable of deleting odor, and capable of deleting color.
In FIG. 1 and FIG. 2, an example is shown where the object “OB” is in contact with or deposited on a part (indicated as a circle area) of the front surface in the [0072] photocatalyst layer 20, and also where the object “OB” is in contact with or deposited on almost the entire front surface in the photocatalyst layer 20, similarly it is a matter of course that the object “OB” is able to be processed to dissolve or react.
The kinds of object “OB” to be cleaned up or reacted may be liquid components such as a tap water from a water supply, drain water, oil, etc. and/or gaseous components such as an air with dirty elements, exhaust gas, etc. Such fluid objects “OB” can also be processed to be cleaned up or reacted that the fluid objects “OB” are subject to be contacted with the surface of the [0073] photocatalyst layer 20 in the photocatalyst device 100.
Photo-activated semiconductors can be used as the photocatalyst (or photocatalytic) materials such as Titanium Dioxide; TiO[0074] ₂(photo activation wavelength; not more than 388 nm), Tungsten Dioxide; WO₂(photo activation wavelength; not more than 388 nm), Zinc Oxide; ZnO (photo activation wavelength; not more than 388 nm) , Zinc Sulfide; ZnS (photo activation wavelength; not more than 344 nm) and Tin Dioxide; SnO₂(photo activation wavelength; not more than 326 nm).
The ultraviolet (UV) rays may be used as the short wavelength light rays, since they can strongly activate the photocatalyst. [0075]
The UV rays are an invisible electromagnetic wave within a range from 380 nano meter(nm) or 3800 angstrom(Å) near visible light rays to X rays. In more details, the UV rays are classified into UV-A rays with wavelength from 380 nm to 315 nm, UV-B rays with wavelength from 380 nm to 315 nm with wavelength from 315 nm to 280 nm and UV-C rays with wavelength from 280 nm to 100 nm. [0076]
The [0077] UV light source 200 emitting the UV light rays L1 may be selected from various vacuum discharge lamps such as a germicidal lamp, black light to cut visible light, UV irradiated fluorescent lamp, halogen lamp and laser to emit coherent UV laser beam.
The germicidal lamp is a conventional low or high pressure mercury lamp using a UV transmissible glass tube such as transparent fused quartz, which emits UV light rays with short wavelength between the range from 250 nm to 280 nm (center wavelength; 253.7 nm) by discharge of mercury. [0078]
The black light is a kind of fluorescent lamp emitting blue color and UV light rays using UV transmissible glass tube with a black filter to cut the UV light rays, or using UV transmissible black filter glass tube to cut only the blue color light rays, which emits UV light rays with medium wavelength between the range from 380 nm to 300 nm by discharge of mercury. [0079]
The UV irradiated fluorescent lamp is transparent glass tube without the black filter instead of the black light, which emits blue color light rays and also UV light rays with medium and long wavelength. [0080]
The halogen lamp is high-pressure mercury lamp adding metal halide inside the lamp tube, which emits UV light rays with medium and long wavelength. [0081]
FIG. 3 and FIG. 4 illustrate more details of the above-mentioned embodiment of the invention, in which the object “OB” is eliminated. [0082]
FIG. 3 shows a schematic enlarged cross-sectional view, taken along the line A-A of FIG. 1, in which scale of FIG. 3 is different from FIG. 1 and FIG. 2. FIG. 4 shows a schematic enlarged cross- sectional view, enlarging a [0083] part 100 a in FIG. 3.
In FIG. 3 and FIG. 4, the [0084] photocatalyst device 100 is composed of the short wavelength rays transmitting member 10 of plate like form and the photocatalyst layer 20 including photocatalyst, which is supported on a surface 10 a of the member 10. Furthermore, the photocatalyst layer 20 may be composed of many photocatalyst particles 20 b and inorganic or organic binding (or bonding) material 20 a, in which the photocatalyst particles 20 b are fixed securely on the surface 10 a of the transmitting member 10 by use of the binder 20 a.
As shown in FIG. 4, the [0085] front surface 10 a is roughly treated by means of conventional emery paper, sand blast, chemical etching, hot stamping, etc., in which a plurality of small projections and/or grooves are formed in the roughly treated surface area. The roughly treated surface area helps the light rays L2 leak out from the front surface 10 a to the photocatalyst layer 20. In addition, the transmitting member 10 and the photocatalyst layer 20 have an increased surface area in the roughly treated area. Therefore, the photocatalyst material included in the photocatalyst layer 20 can be efficiently activated the light rays L2. On the contrary, the rear surface 10 b is smooth as much as possible.
As an alternative, the front surface may have rough areas and smooth areas intermittently or alternately. [0086]
As another alternative, the [0087] rear surface 10 b may have a light reflecting metal coating such as Al or Ni by evaporating or sputtering. Because the light reflecting metal coating (i.e. first covering member) covers the rear surface 10 b and the photocatalyst layer 20 is disposed on the front surface 10 a, light transmitting within the transparent panel or substrate 10 is prevented from escaping from the rear surface 10 b.
As still another alternative, in addition to one linear [0088] UV light source 200 installed at a vicinity of the side terminal 10 c shown in FIG. 1, extra similar UV light source/sources may be installed at a vicinity of at least one of another side terminal/terminals in total four pieces.
The short wavelength rays L[0089] 1 incident to one side terminal 10 c of the short wavelength rays transmitting member 10 becomes the transmitting light rays L2 (not shown in FIG. 3 & FIG. 4, see FIG. 2) transmitting repeatedly inside toward another side terminal 10 d. And the transmitting light rays L2 are subjected to leak out gradually or little by little on the way of transmitting to the another side terminal 10 d, due to existence of the roughly treated surface 10 a.
A lot of [0090] photocatalyst particles 20 b included in the photocatalyst layer 20 are activated by radiation of the light rays L2 leaking out from the surface 10 a of the member 10, so that the object “OB” (shown in FIG. 1 and FIG. 2) contacted or stacked is subjected to be oxidized and/or reduced (cleaned up or reacted) by photocatalyst action of the activated photocatalyst particles 20 b.
As [0091] photocatalyst 20 b, TiO₂can be applied for various fields, since it has an excellent photocatalizing function, long persistency (durability and life) and safety (harmless in case of adding to foods and toiletry goods).
Various embodiments of the invention will be described below. For simplifying explanation of other embodiments, the descriptions already explained will be omitted as much as possible. [0092]
FIG. 7 illustrates a schematic perspective view explaining another embodiment of the invention. [0093]
In this embodiment, an [0094] optical fiber cable 400 including multiple UV transmitting optical fibers are used differently from the first embodiment already explained, in which the multiple optical fibers are tightly bundled to each other in one terminal 400 a in circular form, etc. and the multiple optical fibers are arranged in another terminal 400 b in linear form.
Similarly to the first embodiment, the [0095] photocatalyst device 100 is composed of the short wavelength rays transmitting member 10 (UV transmitting panel) and the photocatalyst layer 20. The object “OB” to be cleaned-up or purified is in contact with, in close to, or is deposited on the photocatalyst layer 20.
As shown in FIG. 7, the short wavelength [0096] light source 300 of “U” shape, etc. is located in an appropriate place distant from the photocatalyst device 100. The optical fiber cable 400 is installed between the light source 200 and one side terminal 10 c of the UV transmitting panel 10.
The [0097] optical fiber cable 400 receives UV light rays emitting from the UV light source 300 at the terminal 400 a of the optical fiber cable 400 and transmits the UV light rays to the other terminal 400 b of the optical fiber cable 400. Since the other terminal 400 b is positioned adjacent one side terminal 10 c of the photocatalyst device 100, the UV light rays transmitted to the other side terminal 400 b are introduced into the UV transmitting panel 10 of the photocatalyst device 100.
This embodiment has such advantage that the [0098] UV light source 300 can be installed at any place distant from the photocatalyst device 100. Therefore, for example, the entire photocatalyst device 100 may be placed inside any enclosure such as a case, a container, a receptacle, a tank, or etc. filled with a gaseous or a liquid object to be cleaned or reacted, while the light source 300 may be placed in any place distant from the photocatalyst device 100, by means of the optical fiber cable 400.
The UV transmitting optical fiber/fibers or cable/[0099] cables 400 capable of transmitting the light rays in ultra violet region are available from famous cable manufacturers, such as Mitsubishi Cable Industries Ltd., Tokyo, Japan.
FIG. 8 illustrates a schematic enlarged cross-sectional view explaining still another embodiment of the invention. [0100]
In this embodiment, the [0101] photocatalyst device 100 is composed of the UV transmitting panel 10 and a pair of photocatalyst layers 20 (with a binder 20 a and photocatalyst particles 20 b) in the front and rear surfaces 10 a and 10 b (while the UV transmitting panel 10 as shown in FIG. 1 has single photocatalyst layer 20 in the front surface 10 a.)
This embodiment has the advantage that the object “OB” such as liquid, gas or particles can be fluidly contacted with both of photocatalyst layers [0102] 20 of the photocatalyst device 100, so as to be subject to be cleaned up or oxidized and/or reduced effectively from both sides.
FIG. 9 illustrates a schematic enlarged cross-sectional view explaining other embodiment of the invention. [0103]
A [0104] photocatalyst device 120 is composed of a UV transmitting member 122 (with a front surface 122 a, a rear surface 122 b, a side terminal 122 c, and another side terminal 122 d etc.) and a photocatalyst layer 124 formed on the front surface 122 a.
In this embodiment, the [0105] photocatalyst device 120 and the UV transmitting member 122 are formed as a tapered panel, while the photocatalyst devices 100 and UV transmitting panels 10 in before-mentioned embodiments have a substantially uniform thickness.
As the [0106] UV transmitting member 122 is of the tapered panel which thickness is gradually decreased from the side terminal 122 c toward the side terminal 122 d in this embodiment, UV light rays can be gradually leaked out to the photocatalyst layer 124 from the front surface 122 a of the UV transmitting member 122, all the photocatalyst layer 124 can be irradiated from rear side by the UV light rays, uniformly in any area of the surface 122 a.
The metal reflected coating is preferably provided on the [0107] rear surface 122 b for the UV light rays not to leak out.
FIG. 10 illustrates a schematic enlarged cross-sectional view explaining further embodiment of the invention. [0108]
In FIG. 10, a [0109] photocatalyst device 130 is composed of a UV transmitting top member 134 formed as concave (or convex) shape as shown in the drawing with a photocatalyst layer 131 formed on a front surface 134 a, a UV transmitting or reflecting bottom panel 132 (with a front surface 132 a and a rear surface 132 b) and an air space 136 in which UV light rays are introduced from a side terminal 134 c, are transmitted to another side terminal 134 d and are leaked out to the photocatalyst layer 131.
The top member with [0110] concave shape 134 and the bottom panel 132 are bonded together between facing portion 138.
FIG. 11 illustrates a schematic enlarged cross-sectional view explaining still further embodiment of the invention. [0111]
In FIG. 11, a [0112] photocatalyst device 140 is composed of a UV transmitting member 142 formed as a substantially uniform thickness panel (UV transmitting panel) with multiple rough light diffusing rear surface 142 b 1 (formed with roughly treated area) and multiple smooth rear surface 142 b 2 alternately, UV transmitting layer 144 coated on the rear surfaces 142 b 1 and 142 b 2, a photocatalyst layer 141 a supported on a front surface 142 a of the UV transmitting panel 142 and another photocatalyst layer 141 b supported on the UV transmitting layer 144.
UV light rays are introduced from a [0113] side terminal 142 c to inside of the UV transmitting panel 142, they are transmitted repeating multiple reflection toward another terminal 142 d according to similar principle to optical fiber, at the same time they are leaking gradually to the photocatalyst layers 141 a and 141 b. As shown in FIG. 11, a distribution density of the multiple rough surfaces 142 b 1 is increased gradually from one side terminal 142 c toward another side terminal 142 d. Therefore, both photocatalyst layers 141 a and 142 b can be irradiated almost uniformly at any place on the surface by the UV light rays.
FIG. 12 illustrates a schematic enlarged cross-sectional view explaining still more embodiment of the invention. [0114]
In FIG. 12, a [0115] photocatalyst device 160 is composed of a UV transmitting top panel 164 with substantially uniform thickness, a photocatalyst layer 161 supported on a front surface 164 a, a bottom panel 166, multiple UV transmitting optical fibers 162 of varying lengths are positioned in a space 167 between both panels 164 and 166 and two spacers 168 to keep and fix both panels 164 and 166 at a uniform gap and the optical fibers 162 at terminals 162 c.
One group of [0116] terminals 162 c (fixed terminals) of the multiple optical fibers 162 end at a same position, while another group of terminals 162 d (free terminals) of the multiple optical fibers 162 end at different positions. The space 167 may be filled with UV transparent liquid or resin.
UV light rays incident to the fixed [0117] terminals 162 c of the multiple optical fibers 162 are transmitted to the free terminals 162 d and irradiate the photocatalyst layer 161 via the top panel 164 to activate it. The bottom panel 166 may have an UV reflecting layer on a surface (not shown in FIG. 12) to effectively reflect the UV light rays to upward.
FIG. 13 illustrates a schematic enlarged cross-sectional view explaining further more embodiment of the invention. [0118]
In FIG. 13, a [0119] photocatalyst device 170 is composed of multiple UV transmitting optical fibers 172 of varying lengths, UV transmitting plastic molding body 174 and a photocatalyst layer 171 on a front surface 174 a of the molding body 174. The optical fibers 172 are embedded in the resin compound 174 such as UV transmitting acrylic resin and silicon resin.
Fixed terminals [0120] 172 c of the multiple optical fibers 172 end at the same position, while free terminals 172 d of the multiple optical fibers 172 end at different positions. UV light rays incident to the fixed terminals 172 c of the multiple optical fibers 172 are transmitted to the free terminals 172 d and irradiate the photocatalyst layer 171 via the UV transmitting plastic molding body 174 to activate the photocatalyst layer 171. The molding body 174 may have a UV reflecting layer (not shown in FIG. 13) on a rear surface 174 b to effectively reflect the UV light rays to] upward.
FIG. 14 illustrates a schematic enlarged cross-sectional view explaining still further another embodiment of the invention. [0121]
In FIG. 14, a [0122] photocatalyst device 180 is composed of multiple UV transmitting optical fibers 182 with different length like branches of a tree, UV transmitting plastic molding body 184 and a pair of photocatalyst layers 181 on front and rear surfaces of the molding body 184. The optical fibers 182 are embedded in the resin compound 184 such as UV transmitting acrylic resin and silicon resin.
Fixed [0123] terminals 182 c of the multiple optical fibers 182 end so as to contact closely each other at a small spot, while free terminals 182 d of the multiple optical fibers 182 end radially at different positions like tree branches.
UV light rays incident to the fixed [0124] terminals 182 c of the multiple optical fibers 182 are transmitted to the free terminals 182 d and irradiate both photocatalyst layers 181 via the UV transmitting plastic molding body 184 to activate the photocatalyst layers 181.
FIG. 15 illustrates a schematic enlarged cross-sectional view explaining still further another embodiment of the invention. [0125]
In FIG. 15, a [0126] photocatalyst device 190 is composed of a UV transmitting panel 191, a phosphor layer 192 supported on a front surface 191 a of the panel 191 and a photocatalyst layer 193 supported on a rear surface 191 b of the panel 191. The phosphor layer 192 may be further composed of multiple phosphor particles and UV transparent binders, which may be made of UV transparent organic resin or inorganic glass frits or powders.
The [0127] phosphor layer 192 includes the phosphor materials capable of emitting visible light when activating by invisible UV rays, such as Ca halo-phosphate for emitting white color, Mg tungstate for emitting blue color, Zn silicate for emitting green color and Ca silicate for emitting orange color.
Therefore, UV rays incident from a [0128] side terminal 191 c are transmitted to another side terminal 191 d and also leaked to activate the phosphor layer 192 from the front surface 191 a and also the photocatalyst layer 193 from the rear surface 191 b.
The [0129] phosphor layer 192 irradiated by the invisible UV rays from the front surface 191 a is subject to be activated and emits visible color light to inform users that the UV light source (See numeral 200 in FIG. 1 and FIG. 7) is on, like a visible indicator.
In various above-mentioned embodiments of the invention, the short wavelength light rays L[0130] 1 are introduced from the side terminal i.e. edge surface (e.g. the numeral 10c in FIG. 1 and FIG. 2) of the photocatalyst panel or pane (e.g. the numeral 100 in FIG. 1 and FIG. 2) or the short wavelength light rays transmitting member (i.e. the transparent substrate 10 in FIG. 1 and FIG. 2).
Alternatively, the short wavelength light rays L[0131] 1 may be introduced or entered from a terminal portion of the front surface i.e. a first major surface (e.g. the numeral 10 a in FIG. 1 and FIG. 2) or the rear surface i.e. the second major surface (e.g. the numeral 10b in FIG. 1 and FIG. 2) of the transparent substrate (e.g. the numeral 10b in FIG. 1 and FIG. 2) and the photocatalytic film i.e. photocatalyst layer (e.g. the numeral 20 in FIG. 1 and FIG. 2) preferably using an optical means or optical coupler/couplers preferably prism/prisms.
According to another (second) aspect of the present invention that is substantially the same as the first aspect of the invention described hereinbefore, in detail. That is, in the second aspect of the invention, a photocatalytic panel or pane (e.g. the [0132] photocatalyst device 100 in e.g. FIG. 1 and FIG. 2) comprises a substantially transparent substrate such as glass substrate (e.g. the light transmission panel 10 in e.g. FIG. 1 and FIG. 2) having a first major surface (e.g. the front surface 10 a in e.g. FIG. I and FIG. 2) and a second major surface (e.g. the rear surface 10 b in e.g. FIG. 1 and FIG. 2) that are substantially parallel (as shown in e.g. FIG. 1 and FIG. 2) with and opposed to each other (as shown in e.g. FIG. 1 and FIG. 2); a photocatalytic film (i.e. the photocatalyst layer 20 in e.g. FIG. 1 and FIG. 2) formed on the first and second major surfaces (10 a and 10 b in e.g. FIG. 1 and FIG. 2); and a light source (the numeral 200 in e.g. FIG. 1 and FIG. 2) for exiting the photocatalytic film (20), the light source (200) being disposed at a position relative to a laminate of the transparent substrate (10) and the photocatalytic film (20) such that light from the light source (200) enters the transparent substrate (10) via a optical prism (i.e. an optical coupler) from a vicinity of a terminal portion of the first or second major surface (or a peripheral portion of the transparent substrate), thereby to reflect the light totally within the laminate (10 and 20) to excite the photocatalytic film 20.
The entire disclosure of U.S. patent application Ser. No. 09/146,917 filed on Sep. 2, 1998 (U.S Pat. No. XXX issued on YY, 2001) including specification, claims, drawings and summary, is incorporated herein by reference in its entirety. The prior foreign application of the U.S. patent application Ser. No. 09/146,917 (U.S Pat. No. W W) is Japanese Patent Application No. 08-80434 filed on Feb. 27, 1996 (Japanese Patent Application Laid-open No. 09-225295 published on Sept. 2, 1997). [0133]
The entire disclosure of the Japanese Patent Application No. 08-80434 is also incorporated herein by reference, the disclosure of which is shown in English and Japanese languages on the internet home page of Japanese Patent Office (JPO), Industrial Property Digital Library: URL -http://www.ipdl.jpo.go.jp/homepg.ipdl. [0134]
While the present invention has been described and shown with reference to preferred embodiments thereof, it will be understood by those skilled in the art that the forgoing and other changes, modifications, combinations or equivalents in form and details can be made therein without departing from the spirit and scope of the present invention. [0135]

Claims

What is claimed is:

1. A photocatalytic panel comprising:

a substantially transparent substrate having (1) first and second major surfaces that are substantially parallel with and opposed to each other and (2) an edge surface that connects said first and second major surfaces together;

a photocatalytic film formed on at least one of said first and second major surfaces; and

a light source for exiting said photocatalytic film, said light source being disposed at a position relative to a laminate of said transparent substrate and said photocatalytic film such that light from said light source enters said transparent substrate from said edge surface and then said light is reflected totally within said laminate, thereby to excite said photocatalytic film and to prevent said light from escaping from said first and second major surfaces of said laminate.

2. The photocatalytic panel according to

claim 1

, wherein said light source is positioned at a vicinity of said edge surface.

3. The photocatalytic panel according to

claim 1

, further comprising:

at least one optical fiber being interposed between a vicinity of said edge surface and said light source positioned away from said laminate; and

thereby light from said light source is delivered into said laminate via said optical fiber.

4. The photocatalytic panel according to

claim 1

, further comprising:

a substantially transparent interlayer film interposed between said photocatalytic film and said first or said second major surface.

5. The photocatalytic panel according to

claim 1

, wherein light from said light source comprises ultraviolet rays.

6. The photocatalytic panel according to

claim 1

, wherein said edge surface of said transparent substrate is substantially perpendicularly to each of said first and second surfaces of said transparent substrate.

7. The photocatalytic panel according to

claim 1

, wherein said photocatalytic film further comprises titanium oxide (titania), tungsten oxide, zinc oxide, zinc sulfide, tin oxide or a combination thereof as a photocatalytic substance.

8. The photocatalytic panel according to

claim 7

, wherein said photocatalytic film further comprises glass or plastic material as a binder.

9. The photocatalytic panel according to

claim 1

, further comprising:

a covering member to cover said second major surface;

wherein said photocatalytic film is disposed on said first major surface; and

thereby light transmitting within said transparent substrate is prevented from escaping from said second major surface.

10. The photocatalytic panel according to

claim 1

, wherein said transparent substrate is made of transparent glass or plastic material.

11. A photocatalytic panel comprising:

a substantially transparent substrate having a first and second major surfaces that are substantially parallel with and opposed to each other;

a photocatalytic film formed on said first and second major surfaces; and

a light source for exiting said photocatalytic film, said light source being disposed at a position relative to a laminate of said transparent substrate and said photocatalytic film such that light from said light source enters said transparent substrate from a peripheral portion of said transparent substrate, thereby to reflect said light totally within said laminate to excite said photocatalytic film.

12. The photocatalytic transparent panel according to

claim 11

, wherein said light source is positioned in a vicinity of said peripheral portion of said transparent substrate.

13. The photocatalytic panel according to

claim 11

, further comprising:

an optical coupler for redirecting light from said light source, said optical coupler being disposed in a vicinity of said peripheral portion of said transparent substrate;

wherein said light source is positioned in a vicinity of said optical coupler; and

thereby light from said light source enters said transparent substrate via said optical coupler.

14. The photocatalytic panel according to

claim 13

, wherein said optical coupler is composed of at least one optical prism.

15. The photocatalytic panel according to

claim 11

, further comprising:

at least one optical fiber interposed between said optical coupler and said light source, and said light source being positioned away from said transparent substrate; and

thereby light from said light source is delivered from said light source into said transparent substrate via said optical fiber.

16. The photocatalytic panel according to

claim 11

, further comprising:

17. The photocatalytic panel according to

claim 11

, wherein light from said light source comprises ultraviolet rays.

18. The photocatalytic panel according to

claim 11

19. The photocatalytic panel according to

claim 11

, wherein said photocatalytic film comprises titanium oxide, tungsten oxide, zinc oxide, zinc sulfide, tin oxide or combination thereof as a photocatalytic substance.

20. The photocatalytic panel according to

claim 19

21. The photocatalytic panel according to

claim 11

, further comprising:

a covering member to cover said second major surface;

wherein said photocatalytic film is disposed on said first major surface; and

22. The photocatalytic panel according to

claim 11

23. A method for activating a photocatalytic panel comprising the steps:

preparing a photocatalytic transparent panel composed of (1) a substantially transparent substrate having first and second major surfaces that are substantially parallel with and opposed to each other and an edge surface that connects said first and second major surfaces together, (2) a photocatalytic film formed on at least one of said first and second major surfaces; and (3) a light source for exiting said photocatalytic film, said light source being disposed at a position relative to a laminate of said transparent substrate and said photocatalytic film;

entering light from said light source into said transparent substrate from said edge surface or a peripheral portion of said transparent substrate, and

reflecting said light within said laminate in accordance with the principles of total internal reflection, thereby said photocatalytic film is excited.

24. The method for activating a photocatalytic panel according to

claim 23

, wherein light from said light source positioned in a vicinity of said edge surface or in a vicinity of said peripheral portion enters said transparent substrate from a vicinity of said edge surface.

25. The method for activating a photocatalytic panel according to

claim 23

, wherein light from said light source positioned away from said laminate is delivered via at least one optical fiber interposed between said light source and a vicinity of said edge surface or said peripheral portion to enter said transparent substrate.

26. The method for activating a photocatalytic panel according to

claim 23

, wherein a substantially transparent interlayer film is interposed between said photocatalytic film and said first or second major surface.

27. The method for activating a photocatalytic panel according to

claim 23

, wherein light from said light source comprises ultraviolet rays.

28. The method for activating a photocatalytic panel according to

claim 23

, said edge surface of said transparent substrate is substantially perpendicularly to each of said first and second surfaces of said transparent substrate.

29. The method for activating a photocatalytic panel according to

claim 23

, wherein said photocatalytic film further comprises titanium oxide (titania), tungsten oxide, zinc oxide, zinc sulfide, tin oxide or a combination thereof as a photocatalytic material.

30. The method for activating a photocatalytic panel according to

claim 23

, wherein said photocatalytic film further comprises glass or plastic material as a binding material.

31. The method for activating a photocatalytic panel according to

claim 23

, wherein said photocatalytic panel further comprises a covering member to cover said second major surface;

wherein said photocatalytic film is disposed on said first major surface; and

32. The method for activating a photocatalytic panel according to

claim 23

, wherein said transparent substrate is made of glass or plastic material.