JP2009181914A - Surface light emitter of ultraviolet rays, photocatalystic device, and air purification method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface light emitter of ultraviolet rays that miniaturizes and has a wide range of irradiation and is excellent in energy-saving. <P>SOLUTION: The surface light emitter 22 of ultraviolet rays includes a light guide plate 32, a reflector 33, and a LED unit 31. The light guide plate 32 includes an incident section 50 for making ultraviolet rays incident, and an emitting surface 51 for emitting the ultraviolet rays incident from the incident section 50 by internally transmitting the ultraviolet rays. The reflector 33 reflects the ultraviolet rays emitted except the emitting surface 51 of the light guide plate 32. The LED unit 31 is arranged on an end of the light guide plate 32. The light guide plate 32 is arranged on the surface opposite to the emitting surface 51 so as to scatter a plurality of truncated cone-shaped recessed reflection section 41. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention mainly relates to an ultraviolet surface emitter using a light guide plate.

  Conventionally, an air cleaning method for removing harmful substances in the air by irradiating the photocatalyst with ultraviolet rays is known. This air purification method using a photocatalyst can be realized with a simple configuration by simply irradiating the photocatalyst with ultraviolet rays. Therefore, a filter or a photocatalyst-supported filter is coated on the floor or wall of a hospital operating room with photocatalyst It is used in various fields, such as being applied to the field of transport that maintains the freshness of fruits and vegetables by circulating air.

  The air cleaning method described above has a configuration in which active oxygen species decompose organic substances when the photocatalyst is irradiated with ultraviolet rays. However, in order to excite the photocatalyst, it is necessary to irradiate the photocatalyst with ultraviolet rays having a wavelength satisfying certain requirements. That requirement is to satisfy the equation of E = hv (E: energy eV, h: Planck constant, v: frequency of light). For example, in a titanium oxide photocatalyst often used as a photocatalyst, E = 3.2 eV, and the wavelength of light that can activate the titanium oxide photocatalyst is 380 nm or less according to the equation of v = 1 / λ (λ: wavelength of light). It turns out that. Therefore, in the air cleaning method using a photocatalyst, an ultraviolet light emitting device that can irradiate ultraviolet rays having a predetermined wavelength is often used. As this ultraviolet light emitting device, a device using a discharge tube type ultraviolet light emitter such as a black light or an ultraviolet fluorescent tube, a device adopting a semiconductor type ultraviolet light emitter represented by an ultraviolet light emitting diode or the like are known.

A method using an ultraviolet light emitting diode in an air cleaning method using a photocatalyst is disclosed in Patent Document 1, for example. This Patent Document 1 uses an ultraviolet light emitting diode as an ultraviolet light source for exciting the photocatalyst in a deodorizing apparatus that performs deodorization using a honeycomb type filter provided with a photocatalyst, and the ultraviolet light from the ultraviolet light emitting diode is The irradiation angle of the ultraviolet light-emitting diode is set so as to irradiate about half from one side of the filter, the photocatalyst is arranged on this one side, and the oxidation catalyst is arranged on the remaining side.
JP 2006-017358 A

  Since the discharge tube type ultraviolet light emitter is a linear light source, it is necessary to widen the irradiation range in order to irradiate the photocatalyst formed in a plate shape with ultraviolet light. Therefore, a method of widening the irradiation range by diffusing ultraviolet rays by separating the light source and the photocatalyst, a method of widening the irradiation range by arranging a plurality of discharge tube type ultraviolet light emitters in parallel, and the like are employed. However, in the former method, since the amount of ultraviolet light emitted from the discharge tube type ultraviolet light emitter is attenuated in proportion to the square of the distance, a portion that is not sufficiently irradiated with ultraviolet light is generated depending on the position of the photocatalyst. Become. On the other hand, in the latter method in which the discharge tube type ultraviolet light emitters are arranged in parallel, a gap is generated between the discharge tube type ultraviolet light emitters arranged in parallel, so the distance from the plate-like photocatalyst is not necessarily constant. . Further, since a discharge tube type ultraviolet light emitter such as a black light has high exothermic property, when the distance between the light source and the photocatalyst is too close, there is a possibility that the filter or the like carrying the photocatalyst is deformed by heat.

  In this respect, the ultraviolet light emitting diode can realize low heat generation, has a long service life compared to a discharge tube type ultraviolet light emitter such as a black light, and is easy to handle as an ultraviolet light emitter. Also, from the viewpoint of energy saving, ultraviolet light emitting diodes are superior to black light and the like. However, since the light from the ultraviolet light emitting diode is a directional point light source, it is necessary to use a plurality of ultraviolet light emitting diodes side by side when the range to be irradiated is wide. As a system for arranging the ultraviolet light emitting diodes, for example, a system in which the ultraviolet light emitting diodes are collectively arranged vertically and horizontally on a plane is known. However, in such a collective array system, it is difficult to reduce the size of the apparatus, and the number of ultraviolet light-emitting diodes required increases significantly as the area irradiated with ultraviolet rays increases. Also in Patent Document 1, there is room for improvement from the viewpoint of uniformly irradiating the entire surface of the plate-like photocatalyst with ultraviolet rays.

  This invention is made | formed in view of the above situation, The objective is to provide the surface-emitting body of the ultraviolet-ray excellent in space saving property and energy saving property.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to the first aspect of the present invention, there is provided an ultraviolet surface emitter configured as follows. That is, the ultraviolet surface emitter includes a light guide plate, a reflector, and an ultraviolet light emitting diode. The light guide plate includes an incident part for allowing ultraviolet rays to enter, and an exit surface for causing the ultraviolet rays incident from the incident part to propagate and emit. The reflector reflects ultraviolet rays emitted from other than the exit surface of the light guide plate. The ultraviolet light emitting diode is disposed at an end of the light guide plate.

  Thereby, the highly directional ultraviolet light of the ultraviolet light emitting diode can be diffused inside the light guide plate, and the ultraviolet light can be irradiated over a wide range through the emission surface. Therefore, the number of light emitting diodes to be used can be reduced, and manufacturing cost and power consumption can be reduced. Further, since the ultraviolet light emitting diode is disposed at the end of the light guide plate, the apparatus can be miniaturized particularly in the thickness direction of the light guide plate. Further, since the ultraviolet light emitting diode is used as a light source, it can contribute to a long life and low heat generation, and the ultraviolet light emitting diode can be manufactured free of mercury, so that the burden on the environment can be suppressed.

  In the ultraviolet light emitter, the light guide plate includes a plurality of finely shaped reflecting portions formed in a convex shape or a concave shape on at least one of the light exit surface and the surface opposite to the light exit surface. It is preferable to be arranged so as to be scattered.

  Thereby, it can guide | invade favorably to an output surface side by reflection or refraction by making an ultraviolet-ray collide with a convex-shaped reflection part or a concave-shaped reflection part within a light-guide plate.

  In the ultraviolet surface emitter, the shape of the reflecting portion is preferably a cone shape, a truncated cone shape, a pyramid shape, or a truncated pyramid shape.

  Thereby, the ultraviolet rays incident on the light guide plate collide with the inclined side surface of the convex reflection portion or the concave reflection portion, and are reflected or refracted, whereby the ultraviolet rays are guided to the emission surface side. Therefore, it is possible to irradiate with sufficient ultraviolet rays from the emission surface.

  In the ultraviolet surface emitter, it is preferable that the reflecting portion is arranged so that the density gradually increases as the distance from the incident portion increases.

  Thereby, it is possible to uniformly irradiate ultraviolet rays from the exit surface regardless of the distance from the incident portion.

  In the ultraviolet surface light emitter, the reflector includes a back reflector disposed to face a surface of the light guide plate opposite to the light exit surface, and the ultraviolet light emitting diode is disposed on the light guide plate. At least one of an end surface reflector disposed to face an end surface other than the end surface, and an irradiator reflector disposed on the end surface where the ultraviolet light emitting diode is disposed so as not to interfere with ultraviolet irradiation. Preferably one is included.

  Thereby, it can prevent effectively that a ultraviolet ray leaks from the surface (back surface) and end surface on the opposite side to the output surface of a light-guide plate by a reflector. Therefore, it is possible to irradiate the ultraviolet rays of the ultraviolet light-emitting diode without waste from the emission surface.

  In the ultraviolet surface emitter, the reflector is preferably made of a material containing aluminum.

  Thereby, the light which leaks from other than the output surface of a light-guide plate can be efficiently reflected in the inside of a light-guide plate with the reflector containing aluminum with a high ultraviolet reflectance. Therefore, the ultraviolet rays of the ultraviolet light-emitting diode can be used effectively, and a strong irradiation intensity can be realized.

  According to the 2nd viewpoint of this invention, a photocatalyst apparatus provided with the said surface emitting body of an ultraviolet-ray is provided.

  Thereby, an ultraviolet-ray can be uniformly irradiated with respect to a photocatalyst from a surface light-emitting body, and a catalytic reaction can be advanced effectively. In addition, since the surface light emitter is reduced in weight and size, the photocatalytic device can be reduced in size and can be disposed in a small space. As a result, a photocatalytic device that can be easily used in various situations can be realized.

  In the said photocatalyst apparatus, it is preferable that a photocatalyst contains a titanium oxide.

  Thereby, air can be more effectively cleaned by using titanium oxide having a strong oxidizing power as a photocatalyst.

  In the photocatalyst device, the photocatalyst is preferably supported by activated carbon.

  As a result, the photocatalyst supported on the highly active activated carbon is irradiated with ultraviolet rays from the surface illuminant, so that it has excellent adsorption power by activated carbon and excellent decomposition ability by the photocatalyst for organic substances that cause odors, for example. It can be demonstrated at the same time.

  According to the third aspect of the present invention, the following photocatalyst air cleaning method is provided. That is, in the first step, the ultraviolet light is irradiated from the ultraviolet light emitting diode to the incident portion of the light guide plate. In the second step, the ultraviolet light incident on the inside of the light guide plate through the incident portion is reflected or refracted by a fine convex reflection portion or concave reflection portion provided in the light guide plate, and further from the emission surface. Let it emit. In the third step, the organic substance is decomposed by irradiating the photocatalyst with ultraviolet rays emitted from the emission surface.

  Thus, the photocatalyst can be uniformly irradiated with the ultraviolet light of the low power consumption ultraviolet light emitting diode using the light guide plate. Therefore, it is possible to provide a highly effective air cleaning method at low cost.

  Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a front view showing a schematic configuration of a photocatalytic air cleaning apparatus according to an embodiment of the present invention.

  An air cleaning device 10 according to this embodiment shown in FIG. 1 includes a photocatalyst device 11 and is configured to clean air by an air cleaning method using a photocatalyst. The air cleaning device 10 includes a photocatalyst device 11, a suction fan 12, a power supply unit 13, and a casing 14. The power supply unit 13 is disposed at an appropriate position of the casing 14 and is configured to be able to supply power to the photocatalytic device 11 and the suction fan 12. The casing 14 is formed with an intake port and an exhaust port (not shown), and the suction fan 12 is disposed at the intake port.

  The air cleaning device 10 includes four photocatalytic devices 11 in a casing 14. With this configuration, when air is sucked from the intake port by the suction fan 12 and guided into the casing 14, harmful substances in the air are decomposed by the respective photocatalyst devices 11, thereby cleaning the air. The cleaned air is discharged from the exhaust port.

  Next, the photocatalytic device 11 will be described. The photocatalytic device 11 includes a photocatalytic filter 21 that carries a photocatalyst that is excited by being irradiated with ultraviolet rays, and an ultraviolet surface emitter 22 as a light source for irradiating the photocatalytic filter 21 with ultraviolet rays.

  FIG. 2 is a photomicrograph showing the state of activated carbon and photocatalyst in the photocatalytic filter 21. As shown in FIG. 2, in the photocatalytic filter 21, titanium oxide as a photocatalyst is present in a state of being supported on activated carbon. With this configuration, the photocatalytic filter 21 adsorbs harmful substances in the air to the activated carbon, excites titanium oxide by the ultraviolet rays emitted from the ultraviolet surface emitter 22, and oxidizes and decomposes the harmful substances by its catalytic action. The photocatalyst is not limited to titanium oxide, and can be changed to, for example, tungsten oxide.

  Next, with reference to FIG. 3, the ultraviolet surface light emitter 22 which is a light source of the photocatalytic device 11 will be described. FIG. 3 is a perspective view showing the configuration of the ultraviolet surface emitter 22. As shown in FIG. 3, the ultraviolet light emitter 22 includes an LED unit 31, two light guide plates 32, a reflector 33 disposed below the light guide plate 32, and a housing 34 for holding them. And a power supply unit 35 for supplying power to the LED unit 31.

  As shown in FIG. 3, the housing 34 is formed in a box shape having an open upper surface. The LED unit 31 is formed in an elongated bar shape and attached to an inner wall on one side of the housing 34. The LED unit 31 has twelve LEDs 40 arranged at equal intervals in the longitudinal direction of the LED unit 31. The two light guide plates 32 are arranged in parallel in the housing 34 such that each end face of the two light guide plates 32 faces the LED unit 31 (LED 40). The light guide plate 32 faces six LEDs 40 per sheet.

  An end surface of the light guide plate 32 facing the LED 40 is an incident portion 50, and a surface on one side in the thickness direction is an emission surface 51. In this configuration, the ultraviolet light emitted from the LED 40 and entering the light guide plate 32 from the incident portion 50 is repeatedly diffused and reflected in the light guide plate 32 and then exits from the emission surface 51 to be the target photocatalyst. The filter 21 is irradiated.

  FIG. 4 shows the relationship between the wavelength of the LED unit 31 of the present embodiment and the ultraviolet intensity. As shown in FIG. 4, in the LED unit 31 of this embodiment, in order to excite titanium oxide, LED40 which irradiates the ultraviolet-ray which the peak wavelength with the highest ultraviolet intensity becomes near 380 nm is used. The power supplied from the power supply unit 35 to the LED unit 31 is approximately 900 mW.

  Next, the material of the light guide plate 32 will be described with reference to FIG. FIG. 5 shows the relationship between wavelength length and transmittance for the trade name ZEONOR (registered trademark) which is a cycloolefin polymer, the trade name TOPAS (registered trademark) which is a cyclic olefin copolymer, and methyl methacrylate resin (PMMA). It is a thing.

  As shown in the graph of FIG. 5, the transmittance of PMMA that is generally distributed is greatly reduced at a wavelength of 400 nm or less due to the influence of an ultraviolet absorber added at the time of manufacture. On the other hand, with respect to the cyclic olefin copolymer and the cycloolefin polymer, the transmittance does not vary much even at a wavelength of 400 nm or less. In addition, about the PMMA, when the mixing | blending thing which does not add an ultraviolet absorber was used, the fall of the transmittance | permeability in wavelength 400nm or less was improved considerably.

  Therefore, in consideration of the wavelength irradiated from the LED 40, it is preferable to form the light guide plate 32 with PMMA without addition of a cyclic olefin copolymer, a cycloolefin polymer, or an ultraviolet absorber. In the present embodiment, a cyclic olefin copolymer is used from the viewpoint of weather resistance and the like.

  As shown in FIG. 3, a reflector 33 is disposed below the two light guide plates 32. As a material of the reflector 33, it is preferable to select a material having a high ultraviolet reflectance. In the present embodiment, a material obtained by vapor-depositing aluminum having high reflection characteristics around 380 nm on an appropriate resin is used. As a result, even when the ultraviolet light incident from the incident portion 50 is about to leak out from the bottom of the light guide plate 32, it is returned to the inside of the light guide plate 32 by the reflector 33.

  Next, the light guide plate 32 will be described with reference to FIGS. 6, 7, and 8. FIG. 6A is a photograph showing the light guide plate 32 of this embodiment, and FIG. 6B is an enlarged photograph of the bottom of the light guide plate 32. FIG. 7 is a side view of the light guide plate 32 schematically showing the irradiation direction of the ultraviolet light applied to the light guide plate 32. FIG. 8 is a schematic diagram showing a state in which ultraviolet rays collide with the concave reflecting portion 41 and are reflected.

  As shown in FIG. 7, on the bottom surface of the light guide plate 32, a plurality of concave reflecting portions 41 formed in a truncated cone shape are arranged. The concave reflecting portion 41 is formed in a truncated cone shape, and is configured to guide the ultraviolet rays to the emission surface 51 when the ultraviolet rays collide with the concave reflecting portion 41. As shown in FIG. 8, the ultraviolet rays that collide with the side surface of the concave reflecting portion 41 are reflected with a large amount of components in the upward direction of the emission surface 51 due to the inclination of the collision surface.

  In the light guide plate 32, the ultraviolet rays travel while being repeatedly reflected by the upper surface, the bottom surface, and the reflector, which are the emission surfaces 51, and are emitted to the outside of the light guide plate 32 when this reflection condition is broken. In the present embodiment, the reflection condition is broken by the concave reflection portion 41, thereby prompting the emission of ultraviolet rays.

  The characteristics of the truncated cone shape will be described with reference to FIG. FIG. 9 shows a ray tracing simulation and shows an angle distribution at a viewing angle of 20 °. FIG. 9A shows the result when a cylindrical concave reflecting portion is used, and FIG. 9B shows the result when a truncated conical concave reflecting portion 41 is used. As shown in FIG. 9, it can be seen that the emission rate in the front direction (0 °) is higher when the truncated conical concave reflecting portion 41 is used than when the cylindrical concave reflecting portion is used. .

  Moreover, it is preferable that the concave reflection part 41 is formed so that an apex angle may be 66 degrees or more and 80 degrees or less. For example, it is conceivable to form a truncated cone shape having a bottom diameter of 55 μm, a height of 30 μm, and an apex angle of 70 °.

  Next, the arrangement of the concave reflecting portion 41 will be described with reference to FIG. FIG. 10 is a plan view schematically showing the arrangement of the concave reflecting portions 41 at the bottom of the light guide plate 32 of the present embodiment. As shown in FIG. 10, the concave reflecting portion 41 is arranged so that the density becomes sparse to dense as the distance from the ultraviolet incident portion 50 side increases. That is, the light guide plate 32 is configured such that the arrangement density is the smallest in the vicinity of the incident part 50, the arrangement density is slightly large in the central part, and the arrangement density is the largest in the position farthest from the incident part 50. Specifically, for example, the concave reflection parts 41 per unit area are arranged so as to increase according to a predetermined function.

  In this way, by changing the density of the concave reflecting portion 41 according to the distance from the incident portion 50, the illuminance of ultraviolet rays emitted from the emission surface 51 can be made more uniform. And this concave reflection part 41 is optimally arrange | positioned in the ratio of about 600,000 pieces, for example in the range of 100 mm x 50 mm. In addition, as an arrangement method of the concave reflection portion 41, regular arrangement, random arrangement, or the like can be appropriately selected. However, in consideration of the uniformity of the luminance irradiated from the emission surface 51 and the viewpoint of preventing moire, it is preferable that the concave reflecting portions 41 are arranged at random.

  Moreover, since LED40 is low heat_generation | fever, the light-guide plate 32 can be arrange | positioned close to the photocatalyst filter 21. FIG. Thus, the ultraviolet light is prevented from being attenuated before reaching the photocatalytic filter 21, and the entire surface of the photocatalytic filter 21 formed in a plate shape can be uniformly irradiated using the ultraviolet light emitter 22.

FIG. 11 shows the result of measuring the light emission luminance of the ultraviolet surface emitter 22 of the present embodiment. The table of FIG. 11 is obtained by measuring the luminance of a total of 25 regions divided by dividing the light emitting surface of the light guide plate 32 vertically and horizontally with a spectral radiance meter. As shown in FIG. 11, the maximum value of luminance is 2.81 cd / m ² , the minimum value is 1.82 cd / m ² , and the average value is 2.21 cd / m ² . When the degree of uniformity (minimum value / maximum value) is calculated, it is 65%, indicating that light is emitted with good degree of uniformity. Moreover, the illuminance measured with the UV integrated light meter is an average of 0.3 mW / cm ² . Therefore, even if there is no configuration such as a diffusion plate used in a backlight or the like, the light guide plate 32 of the present embodiment can irradiate ultraviolet rays uniformly from the emission surface 51. Thereby, while being able to hold down manufacturing cost, further size reduction can be achieved.

  Next, with reference to FIG. 12, the manufacturing method of the light-guide plate 32 provided with the concave-shaped reflection part 41 is demonstrated. FIG. 12 is a process diagram sequentially illustrating a method for manufacturing the light guide plate 32. In the present embodiment, the light guide plate 32 is manufactured by the UV lithography method. Specifically, as shown in FIG. 12A, a positive resist layer 61 is uniformly applied and solidified on a flat substrate 60 formed of silicon or the like. Then, the UV mask 62 is disposed above the substrate 60. In the UV mask 62, a circular pattern 63 capable of transmitting ultraviolet rays is arranged so as to become denser from one side of the UV mask 62 toward the other side.

  With this configuration, the resist layer 61 is exposed by an unillustrated ultraviolet irradiation device. At this time, a part of the ultraviolet light applied to the edge of the circular pattern 63 is diffracted and applied to the resist layer 61 obliquely. Due to this diffraction phenomenon, the irradiated portion of the resist layer 61 irradiated obliquely is subjected to half shadow exposure. When the exposed portion is removed by the development process in this state, a resist layer 61 having a tapered (conical frustum-shaped) recess is formed.

  Next, as shown in FIG. 12B, Ni electroforming is performed on the resist layer to manufacture a molding die 65 shown in FIG. And the raw material of the light-guide plate 32 is injection-molded for this shaping die 65 using the injection molding apparatus 66 like FIG.12 (d). As a result, the light guide plate 32 shown in FIG. Thereby, the light guide plate 32 having a fine shape that is difficult to realize by machining can be manufactured. In addition, the manufacturing method of the shaping die 65 can be changed as appropriate. For example, a negative resist layer can be used, or other lithography techniques such as an X-ray lithography method can be used.

  Next, the decomposition characteristics of the air cleaning device 10 of the present embodiment will be described with reference to FIG. FIG. 13 is a graph showing the results of measuring the decomposition performance of the air cleaning device 10 of this embodiment when 160 ppm of ammonia gas was injected into a 2.4 m × 2.6 m × 6 m sealed space. is there. This measurement was performed with the combined weight of activated carbon and photocatalyst being 1.72 g (titanium oxide 0.384 g). As shown in FIG. 13, the concentration of ammonia gas, which was initially 160 ppm, has decreased to 40 ppm after 15 hours due to the cleaning action of the air cleaning device 10 of the present embodiment. As described above, by using the air cleaning device 10 of the present embodiment, the ammonia gas can be effectively decomposed.

  Next, with reference to FIG. 14, a decomposition experiment of toluene when the photocatalytic device 11 of the present embodiment is used alone will be described. In this experiment, two pieces in which 100 ppm of toluene was injected into a 3 liter Tedlar pack were prepared, the photocatalyst device 11 was placed in one tedlar pack, and the other was a tedlar pack for a blank test in which no photocatalyst was placed. In addition, 100 ppm of toluene was inject | poured into the Tedlar pack which has arrange | positioned the photocatalyst every 30 minutes.

  FIG. 14A compares the toluene concentrations of the Tedlar pack in which the photocatalytic device 11 is arranged and the Tedlar pack for the blank test. FIG. 14 (b) shows the change in the concentration of toluene over time and the change over time in the total amount of decomposition of toluene.

  As shown in FIG. 14 (a), the Tedlar pack for the blank test does not change the toluene concentration from 100 ppm, whereas the Tedlar pack in which the photocatalyst is arranged decreases the toluene concentration to 1.5 ppm after 30 minutes. . Further, in the Tedlar pack in which the photocatalyst is arranged, even when toluene is added, it is reduced to 2.0 ppm again after 30 minutes. Moreover, even if the operation of adding 100 ppm of toluene every 30 minutes is repeated about 10 times, as shown in FIG. 14B, the decomposition ability of the photocatalytic device 11 is not lowered at all.

  As described above, the ultraviolet surface emitter 22 of the present embodiment includes the light guide plate 32, the reflector 33, and the LED 40. The light guide plate 32 includes an incident part 50 that makes ultraviolet rays enter, and an emission surface 51 that causes the ultraviolet rays incident from the incident part 50 to propagate inside and exit. The reflector 33 reflects ultraviolet rays emitted from other than the emission surface 51 of the light guide plate 32. The LED 40 is disposed at the end of the light guide plate 32.

  With this configuration, the highly directional UV light of the LED 40 can be diffused inside the light guide plate 32, and the UV light can be irradiated over a wide range with good uniformity through the emission surface 51. Therefore, the number of LEDs 40 to be used can be reduced, and the manufacturing cost and power consumption can be reduced. Further, since the LED 40 is disposed at the end of the light guide plate 32, the apparatus can be downsized particularly in the thickness direction of the light guide plate 32. Further, since the LED 40 is used as a light source, it is possible to realize a long life and low heat generation, and an ultraviolet light emitting diode can be manufactured free of mercury, so that an environmental load can be suppressed.

  Further, in the light guide plate 32 constituting the ultraviolet surface light emitter 22 of the present embodiment, a plurality of concave reflection portions 41 are arranged on the surface opposite to the emission surface 51.

  With this configuration, the ultraviolet rays that collide with the concave reflecting portion 41 in the light guide plate 32 can be favorably guided to the exit surface side by reflection or refraction.

  Further, in the ultraviolet surface light emitter 22 of the present embodiment, the shape of the concave reflecting portion 41 is a truncated cone shape.

  With this configuration, the ultraviolet light incident on the light guide plate 32 is favorably guided to the emission surface 51 by colliding with the slope of the concave reflecting portion 41. Accordingly, it is possible to irradiate sufficient ultraviolet rays from the emission surface 51.

  Further, in the ultraviolet surface light emitter 22 of the present embodiment, the concave reflecting portion 41 is disposed so that the density gradually increases as the distance from the incident portion 50 increases.

  With this configuration, it is possible to uniformly irradiate ultraviolet rays from the emission surface 51 regardless of the distance from the incident portion 50.

  Moreover, as for the ultraviolet-ray surface light-emitting body 22 of this embodiment, the reflector 33 is comprised with the material containing aluminum.

  With this configuration, light that is about to leak from other than the exit surface 51 of the light guide plate 32 can be efficiently reflected to the inside of the light guide plate 32 by the reflector 33 containing aluminum having a high ultraviolet reflectance. Therefore, the ultraviolet rays of the LED 40 can be used effectively, and a strong irradiation intensity can be realized.

  Further, the photocatalytic device 11 of this embodiment includes the ultraviolet surface light emitter 22.

  With this configuration, it is possible to uniformly irradiate the photocatalyst with ultraviolet rays from the ultraviolet surface illuminant 22 and to effectively advance the catalytic reaction. Moreover, since the weight reduction and size reduction of the ultraviolet-ray surface light-emitting body 22 are implement | achieved, size reduction of the photocatalyst apparatus 11 can be implement | achieved and it can arrange | position to a place with a small space. As a result, the photocatalytic device 11 that can be easily used in various situations can be realized.

  Moreover, in the photocatalyst device 11 of the present embodiment, the photocatalyst contains titanium oxide.

  With this configuration, air can be more effectively cleaned by using titanium oxide having strong oxidizing power as a photocatalyst.

  In addition, the photocatalytic device 11 of the present embodiment is configured to carry titanium oxide that is a photocatalyst by activated carbon.

  With this configuration, the photocatalyst supported on the activated carbon with high adsorptivity is irradiated with ultraviolet rays from the surface emitter, so it has excellent adsorption power with activated carbon and excellent decomposition ability with photocatalyst for organic substances that cause odors, etc. Can be demonstrated at the same time.

  In addition, as described above, the air cleaning method using the photocatalytic device 11 of the present embodiment is performed in the steps shown below. That is, in the first step, ultraviolet rays are irradiated from the LED 40 to the incident portion 50 of the light guide plate 32. In the second step, the ultraviolet light incident on the inside of the light guide plate 32 through the incident portion 50 is reflected by the truncated conical concave reflection portion 41 provided on the surface opposite to the exit surface 51 of the light guide plate 32, and further The light is emitted from the emission surface 51. In the third step, the organic substance is decomposed by irradiating the photocatalyst with ultraviolet rays emitted from the emission surface 51.

  With this configuration, it is possible to uniformly irradiate the photocatalyst with the ultraviolet light of the LED 40 with low power consumption using the light guide plate 32. Therefore, it is possible to provide a highly effective air cleaning method at low cost. When this is used to efficiently decompose harmful volatile organic substances (VOC gas; benzene, toluene, xylene, etc.), food waste odor and ammonia that are slightly present in the atmosphere, and maintain the freshness of fresh food However, it is possible to provide an air cleaning device that is highly effective.

  Next, a modification of the ultraviolet surface emitter will be described with reference to FIG. FIG. 15 is a perspective view showing a modification of the ultraviolet surface emitter 22. In addition, in a modification, the same code | symbol may be attached | subjected to drawing and the description similar to the said embodiment may be abbreviate | omitted.

  As shown in FIG. 15, the ultraviolet surface emitter 80 includes an LED unit 81, a light guide plate 82, a housing 83, and a reflector. The LED unit 81 of the modification is provided with four LEDs 40. The LED 40 is disposed on the end face of the incident portion 50 as in the above embodiment.

  The ultraviolet surface light emitter 80 according to the modified example is adjacent to the incident portion 50, a back reflector 84 disposed below the light guide plate 82, an end surface reflector 85 covering the end surface opposite to the incident portion 50, and the incident portion 50. End surface reflectors 86 and 87 that respectively cover the end surfaces. In addition, these reflectors are not limited to the structure in which the back reflector 84 and the end surface reflectors 85, 86, and 87 are integrally formed, and can be configured as separate and independent components.

  As described above, the reflector of the ultraviolet surface light emitter 80 according to the modified example includes the back reflector 84 disposed opposite to the surface opposite to the exit surface 51 of the light guide plate 82, and the LED 40 disposed on the light guide plate 82. And end surface reflectors 85, 86, 87 arranged to face end surfaces other than the end surfaces.

  With this configuration, the back reflector 84 and the end reflectors 85, 86, and 87 can effectively prevent ultraviolet rays from leaking from the surface (rear face) and the end face opposite to the exit surface 51 of the light guide plate 32. . Therefore, the ultraviolet rays of the LED unit 81 can be irradiated from the emission surface 51 without waste. In the above configuration, a part of the end surface reflector 85 can be omitted. In addition, the configuration can be changed as appropriate, such as a configuration in which an irradiation portion reflector disposed in the incident portion 50 is added within a range that faces the incident portion 50 and does not interfere with the ultraviolet irradiation of the LED 40.

  Moreover, in the said embodiment, although the concave reflection part 41 is the structure arrange | positioned at the bottom part (namely, part on the opposite side to the said output surface 51) of the light-guide plate 32, this structure can be changed as follows. . With reference to FIG.16 and FIG.17, the modification of the reflection part which the light-guide plate 32 has is demonstrated. FIG. 16 shows a configuration in which the light guide plate 32 has an upper surface convex reflection portion 91, a configuration in which the light guide plate 32 has an upper surface concave reflection portion 92, and the light guide plate 32 has a concave reflection portion 41 and an upper surface concave reflection portion 92 on the upper surface. It is the schematic diagram which each showed the structure. FIG. 17 is a graph showing the result of simulating the relationship between the height and luminance of the upper surface convex reflection part 91, the upper surface concave reflection part 92, and the concave reflection part 41.

  As shown in FIG. 16A, the light guide plate 32 can be configured to include an upper surface convex reflection portion 91 on the emission surface 51. This upper surface convex reflecting portion 91 is filled with resin and protrudes outward from the emission surface 51. Also by this, the incident ultraviolet rays are reflected or refracted by the upper surface convex reflection part 91 and emitted, whereby the uniformity of the emitted ultraviolet rays can be improved. Also, as shown in FIG. 17, the brightness of the upper convex reflection part 91 is improved until the dot height is 15 μm, but the brightness is lowered when the dot height exceeds 20 μm. Therefore, it is preferable that the dot height of the upper surface convex reflection portion 91 is smaller than 20 μm and as high as possible within the range where the luminance does not decrease.

  Further, as shown in FIG. 16B, the light guide plate 32 may be configured such that the upper surface concave reflection portion 92 is disposed on the emission surface 51 side. Also by this, the uniformity of the ultraviolet rays emitted from the emission surface can be improved by the ultraviolet rays incident from the incident portion 50 colliding with the upper surface concave reflection portion 92 and reflecting or refracting.

  Further, as shown in FIG. 16C, the light guide plate 32 may be configured such that the concave reflection portion 41 is disposed at the bottom and the upper surface concave reflection portion 92 is provided on the emission surface 51 side. The ultraviolet rays incident from the incident portion 50 are reflected or refracted by the concave reflection portion 41 and reflected or refracted by the upper surface concave reflection portion 92, so that the ultraviolet rays are diffused. Thereby, ultraviolet rays can be more uniformly emitted together with the concave reflecting portion 41 at the bottom.

  Although the preferred embodiment of the present invention has been described above, the above configuration can be further modified as follows.

  Although the LED units are arranged in a line in the embodiment and the modification, the configuration of the LED units can be appropriately changed according to circumstances. For example, it is possible to change the arrangement of the LED units in a plurality of rows or increase the number of LEDs arranged according to the irradiation intensity. Even in such a configuration, it is possible to provide an ultraviolet surface emitter capable of irradiating ultraviolet rays over a wide range while minimizing the number of necessary LEDs by using the light guide plate.

  Moreover, in the said embodiment, although the shape of the concave reflection part 41 is formed in the truncated cone shape, this structure can also be changed. For example, the shape of the concave reflection portion or the convex reflection portion can be changed to a conical shape, a pyramid shape, a truncated pyramid shape, or the like. Moreover, the above-mentioned convex-shaped reflection part or concave-shaped reflection part is not limited to the structure whose bottom part is a perfect circle or a regular polygon.

  The air cleaning device 10 of the above embodiment can be diverted to various fields such as automobiles and facilities that require transport and sterilization of fresh food. Further, since the number of LEDs can be reduced and the thickness direction of the ultraviolet light emitter 22 can be reduced as shown in the above embodiment, the ultraviolet light emitter 22 can be disposed even in a small space. For example, it is suitable when it is used by being embedded in the inner wall of a refrigerator or the like.

  Further, the ultraviolet light emitter of the present invention can also be used as an insect attracting device. Insects have the property of gathering in a light source (phototaxis) and are particularly capable of sensing ultraviolet rays. Therefore, insects can be attracted effectively by using a surface light emitter having a wide irradiation range as an attracting device. The attracted insect is killed by an appropriate method such as an adhesive sheet. Thereby, even when agrochemicals cannot be used, insects can be exterminated, and damage such as contamination of insects in a food factory can be effectively prevented.

  Moreover, it can be set as the structure which equips a motor vehicle with the decomposition | disassembly deodorizing function using a photocatalyst. As described above, since the photocatalytic device 11 of the above embodiment is configured compactly, installation is easy even when the space is limited.

  Moreover, the ultraviolet-ray surface-emitting body of this invention can be used also for the growth of the plant using an ultraviolet-ray, etc. In this case, the plant can be irradiated with ultraviolet rays over a wide range with a minimum number of LEDs.

  In addition, at least the following technical thought can be grasped | ascertained from embodiment described above and its modification.

A light guide plate comprising: an incident portion that makes ultraviolet rays incident; and an emission surface that propagates and emits ultraviolet rays that are incident from the incident portion;
A reflector for reflecting the ultraviolet rays emitted from other than the exit surface of the light guide plate;
A discharge tube type ultraviolet light emitter disposed at an end of the light guide plate;
An ultraviolet surface light emitter characterized by comprising:

  With this configuration, the discharge tube type ultraviolet light emitter, which is a line light source, can be a surface light emitter with a simple configuration. Since the number of discharge tube type ultraviolet light emitters is reduced and the structure is simple, the manufacturing cost can be reduced.

In the ultraviolet light emitter using the above discharge tube type ultraviolet light emitter,
The light guide plate has a plurality of fine-shaped convex reflectors or concave reflectors on the exit surface, the opposite surface of the exit surface, or both the exit surface and the opposite surface of the exit surface. Are arranged so as to be scattered.

In addition, in the ultraviolet light emitter using the above discharge tube type ultraviolet light emitter,
The convex reflection part and the concave reflection part have a conical shape, a truncated cone shape, a pyramid shape, or a truncated pyramid shape.

  Thereby, the ultraviolet rays incident on the light guide plate are guided to the emission surface side by being reflected or refracted by the convex reflection portion and the concave reflection portion, so that the ultraviolet rays can be irradiated over a wide range through the emission surface. Accordingly, it is possible to provide an ultraviolet surface emitter using a discharge tube type ultraviolet emitter capable of sufficient ultraviolet irradiation with a minimum configuration as a light source.

The front view which shows the outline of the photocatalyst air cleaning apparatus which concerns on one Embodiment of this invention. Photomicrograph showing activated carbon and photocatalyst The perspective view which shows the ultraviolet-ray surface light-emitting body of this embodiment. The graph which shows the wavelength characteristic of LED of this embodiment. The graph which shows the spectral characteristic of the ultraviolet-ray for every material of a light-guide plate. The photo of a light-guide plate and the microscope picture which shows the mode of a convex-shaped reflection part. The schematic diagram which shows the path | route of the ultraviolet-ray which injects into a light-guide plate. The schematic diagram which shows the shape of a convex-shaped reflection part. The graph which shows the radiation | emission characteristic of a convex-shaped reflection part. The top view which shows typically arrangement | positioning of the convex-shaped reflection part of a light-guide plate. The table | surface which shows the brightness | luminance of a surface light emitter for every division. The flowchart which shows the manufacturing method of a light-guide plate. The graph which shows the density | concentration change of ammonia. The graph which shows the density | concentration change of toluene. The perspective view which shows the ultraviolet-ray surface light-emitting body of a modification. The schematic diagram which shows the mode of the light-guide plate of a modification. The graph which shows the relationship between the shape and arrangement | positioning location of a reflection part, and a brightness | luminance.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Air purifier 11 Photocatalyst apparatus 21 Photocatalyst filter 22 Ultraviolet surface light-emitting body 31 LED unit (ultraviolet light emitting diode)
32 Light guide plate 33 Reflector 41 Concave reflector 91 Upper surface convex reflector 92 Upper surface concave reflector

Claims (10)

A light guide plate comprising: an incident portion that makes ultraviolet rays incident; and an emission surface that propagates and emits ultraviolet rays that are incident from the incident portion;
A reflector for reflecting the ultraviolet rays emitted from other than the exit surface of the light guide plate;
An ultraviolet light emitting diode disposed at an end of the light guide plate;
An ultraviolet surface light emitter characterized by comprising: An ultraviolet surface emitter according to claim 1,
In the light guide plate, at least one of the light exit surface and the surface opposite to the light exit surface is arranged so as to be dotted with a plurality of fine-shaped reflection portions formed in a convex shape or a concave shape. Ultraviolet surface emitter. An ultraviolet surface emitter according to claim 2,
The shape of the reflecting portion is a cone shape, a truncated cone shape, a pyramid shape, or a truncated pyramid shape, and an ultraviolet surface emitter. An ultraviolet surface emitter according to any one of claims 1 to 3,
The surface emitting body of ultraviolet rays, wherein the reflection portion is arranged so that the density gradually increases as the distance from the incident portion increases. An ultraviolet surface emitter according to any one of claims 1 to 4,
The reflector is
A back reflector disposed opposite to the surface of the light guide plate opposite to the exit surface;
An end surface reflector disposed to face an end surface other than the end surface on which the ultraviolet light emitting diode is disposed in the light guide plate;
An irradiation part reflector disposed on the end face where the ultraviolet light emitting diode is disposed so as not to interfere with ultraviolet irradiation;
An ultraviolet surface light emitter comprising at least one of the above. An ultraviolet surface emitter according to any one of claims 1 to 5,
The reflector is made of a material containing aluminum, and is an ultraviolet surface light emitter.   A photocatalyst device comprising the ultraviolet light emitter according to any one of claims 1 to 6. The photocatalytic device according to claim 7,
A photocatalyst device, wherein the photocatalyst contains titanium oxide. The photocatalyst device according to claim 7 or 8,
A photocatalyst device characterized by supporting a photocatalyst by activated carbon. A first step of irradiating ultraviolet light from the ultraviolet light emitting diode to the incident portion of the light guide plate;
A second step of reflecting or refracting ultraviolet rays incident on the inside of the light guide plate from the incident portion at a fine convex reflection portion or concave reflection portion provided in the light guide plate, and further emitting from the exit surface;
A third step of decomposing the organic material by irradiating the photocatalyst with ultraviolet rays emitted from the emission surface;
An air cleaning method comprising: