Lighting device

Abstract

To provide a lighting device capable of not only functioning as a lighting device but also sterilizing or deodorizing surrounding air by incorporating a plasma processing apparatus having a simple structure into the lighting device.SOLUTION: A lighting device 30 includes: a lighting element 23; a lighting element cover 22 for protecting the lighting element 23; a dielectric layer 11; and a pair of electrode layers 12 and 13 provided on both sides of the dielectric layer 11, and includes: a plasma generation part 50 that generates a plasma; and a power supply part for applying an AC voltage to the pair of electrode layers. In the lighting device 30, the plasma generation part 50 is disposed on the lighting element cover 22.SELECTED DRAWING: Figure 10

Description

[Technical Field]

[0001] The present invention relates to a lighting device equipped with a plasma processing device capable of plasma processing the surrounding air. [Background technology]

[0002] In recent years, the outbreak of the COVID-19 pandemic has led to a surge of interest worldwide in defense measures against viruses and bacteria. Against this backdrop, plasma processing is being developed as a new defense against viruses and bacteria. Regarding plasma processing technology, a method called Dielectric Barrier Discharge (DBD) has been developed in recent years, making it possible to generate low-temperature plasma at atmospheric pressure.

[0003] When gases containing oxygen and moisture, such as air, are treated with plasma, they generate reactive species (ROS), such as singlet oxygen, hydrogen peroxide, OH radicals, peroxide radicals, and ozone. These reactive species can decompose, kill, or inactivate microorganisms through oxidation reactions and other processes. Examples of microorganisms include various viruses, bacteria, and mold. The reactive species can also decompose chemical substances through oxidation reactions and other processes. Therefore, plasma treatment can be used not only for sterilization but also for deodorization and other purposes.

[0004] Various plasma processing apparatuses have been developed to perform continuous plasma processing while flowing air. For example, Patent Document 1 discloses a plasma generating apparatus in which two or more plasma generating units are stacked, each of which has a flat first electrode and a flat second electrode facing each other across a gap. Patent Document 2 also discloses an air purifier that includes a plasma generator having a structure in which electrode members, at least a portion of which is covered with a dielectric, are arranged in the thickness direction and generate plasma in the gap between adjacent electrode members, a power source that applies voltage, and a blower that blows air through the gap and releases the generated ozone along with the air. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-190472 [Patent Document 2] Japanese Patent Application Publication No. 2018-130208 Summary of the Invention [Problem to be solved by the invention]

[0006] Both the plasma generator described in Patent Document 1 and the air purifier described in Patent Document 2 have a structure in which a large number of electrode layers, dielectric layers, and air gap layers are repeatedly stacked in the thickness direction to treat air with plasma. Furthermore, they require air to be forced to pass through the thin spaces of the air gap layers. In other words, neither device has a simple structure that can be attached to a lighting device and used to treat the surrounding air with plasma.

[0007] In our daily lives, sterilization and deodorization functions are required in various aspects of our living environment. Therefore, it would be extremely useful to incorporate plasma processing equipment into everyday products, such as lighting fixtures. Here, "sterilization" is used in a broad sense to include not only the elimination of microorganisms but also "inactivation," which stops or reduces the activity of microorganisms (the same applies below).

[0008] The present invention has been made in view of the above-mentioned circumstances, and aims to provide a lighting device that not only functions as a lighting device but also sterilizes or deodorizes the surrounding air by incorporating a plasma processing device with a simple structure into the lighting device. [Means for solving the problem]

[0009] In order to solve the above-mentioned problems, the present invention has the following configuration. (1) A lighting device comprising: a lighting element; a lighting element cover for protecting the lighting element; a plasma generating unit having a dielectric layer and a pair of electrode layers provided on both sides of the dielectric layer, and generating plasma; and a power supply unit for applying an AC voltage to the pair of electrode layers, wherein the plasma generating unit is installed on the lighting element cover. (2) The lighting device according to (1), wherein the electrode layer has a through-hole penetrating in the thickness direction. (3) The lighting device according to (1) or (2), wherein the plasma generating section is flexible. (4) The lighting device according to (1) or (2), wherein the plasma generating section has a mask layer on the outside of at least one of the pair of electrode layers. (5) The lighting device according to (1) or (2), wherein the plasma generating section is transparent. [Effects of the Invention]

[0010] The lighting device of the present invention incorporates a plasma processing device with a simple structure into the lighting device, so that it not only functions as a lighting device but also can sterilize or deodorize the surrounding air. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view for explaining a plasma generating unit. [Figure 2] FIG. 2 is a perspective view for explaining a plasma generating unit. [Figure 3] FIG. 2 is a cross-sectional view illustrating a plasma generating unit. [Figure 4] FIG. 10 is a perspective view for explaining a plasma generating unit according to a first modified example. [Figure 5] FIG. 10 is a perspective view for explaining a plasma generating unit according to a second modified example. [Figure 6] FIG. 10 is a perspective view for explaining a plasma generating unit according to a third modified example. [Figure 7] FIG. 10 is a cross-sectional view illustrating a plasma generating unit according to a fourth modified example. [Figure 8] FIG. 10 is a cross-sectional view illustrating a plasma generating unit according to a fifth modified example. [Figure 9] FIG. 13 is a cross-sectional view illustrating a plasma generating unit according to a sixth modified example. [Figure 10] 1 is a schematic cross-sectional view of a lighting device according to a first embodiment. [Figure 11] FIG. 10 is a schematic cross-sectional view of a lighting device according to a second embodiment. [Figure 12] FIG. 10 is a schematic cross-sectional view of a lighting device according to a third embodiment. [Figure 13] FIG. 10 is a schematic cross-sectional view of a lighting device according to a fourth embodiment. [Figure 14] FIG. 10 is a schematic cross-sectional view of a lighting device according to a fifth embodiment. [Figure 15] FIG. 10 is a schematic cross-sectional view of a lighting device according to a sixth embodiment. [Figure 16] FIG. 13 is a schematic cross-sectional view of a lighting device according to a seventh embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described in detail, but the embodiments of the present invention are not limited to the embodiments described below. Each embodiment and modified example can be applied in appropriate combination. Furthermore, directions such as "upper" and "lower" in the description are used for convenience of explanation and do not limit the directions of the present invention.

[0013] The lighting device of this embodiment includes a lighting element and a lighting element cover that protects the lighting element, as well as a plasma generating unit and a power supply unit. The plasma generating unit of this embodiment has a dielectric layer and a pair of electrode layers provided on both sides of the dielectric layer. Mask layers may be provided on the opposite sides (outsides) of the pair of electrode layers from the dielectric layer. The power supply unit can apply an AC voltage to the pair of electrode layers. In dielectric barrier discharge, a dielectric layer is provided between two electrode layers, and an AC voltage is applied between the two electrode layers, thereby generating plasma in the dielectric layer sandwiched between the two electrode layers. First, the plasma generating unit will be described.

[0014] <Basic structure of the plasma generation unit> As shown in Figures 1 and 2, the plasma generating unit 10 includes a dielectric layer 11, an upper electrode 12, a lower electrode 13, an upper mask layer 14, and a lower mask layer 15. The plasma generating unit 10 is preferably a thin-film member that is flexible. For convenience, the dielectric layer 11 is expressed as a single dielectric, but it may also be a laminate of one or more dielectrics containing air. The mask layer is provided to protect the electrodes and improve the ease of assembly of the electrodes, and may be omitted. Furthermore, by appropriately selecting the thickness and position of the mask layer, excessive electric field concentration on the electrodes can be prevented, thereby extending the life of the electrodes.

[0015] As shown in FIGS. 1 to 3, the dielectric layer 11 is a layer member disposed between the upper electrode 12 and the lower electrode 13. The material of the dielectric layer 11 is preferably an insulating material with a large breakdown voltage so that discharge does not easily occur between the upper electrode 12 and the lower electrode 13. Furthermore, since the material of the dielectric layer 11 will be exposed to the generated plasma, it is preferably a material that is durable against active substances generated in the plasma. The material of the dielectric layer 11 is preferably a material selected mainly from glass, ceramics, and synthetic resins. The term "mainly" means that the component composition is 50% by mass or more (the same applies hereinafter).

[0016] Examples of glass include soda-lime glass (soda glass), borosilicate glass, quartz glass, lead glass, and oxide glass. Examples of ceramics include alumina, silica, titanium oxide, zinc oxide, and mica (layered silicate). Synthetic resins include thermoplastic resins and thermosetting resins. Examples of thermoplastic resins include general-purpose resins such as polyolefin, polystyrene, polyvinyl acetate, polyurethane, polylactic acid, ABS resin, AS resin, acrylic resin, polyvinyl chloride, and polyvinylidene chloride; engineering plastics such as polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polyester, and cyclic polyolefin; super-engineering plastics such as polyphenylene sulfide, polysulfone, polyethersulfone, polyarylate, liquid crystal polymer, polyetheretherketone, polyimide, polyamideimide, and polyetherimide; and fluorine-based resins. Examples of thermosetting resins include phenolic resin, melamine resin, urea resin, alkyd resin, epoxy resin, unsaturated polyester resin, and polyurethane resin. Among these synthetic resins, silicone-based resins, polyimide-based resins, and Teflon®-based resins, which are highly durable, are particularly preferred. The thickness of the dielectric layer 11 is not particularly limited, but is preferably 0.01 mm to 5.0 mm, more preferably 0.1 mm to 3.0 mm, and even more preferably 0.1 to 1.0 mm, in order to achieve light weight and compactness.

[0017] As shown in FIGS. 2 and 3, the upper electrode (electrode layer) 12 and the lower electrode (electrode layer) 13 are layer members disposed on the front and back of the dielectric layer 11. The upper electrode 12 and the lower electrode 13 are each provided with a through-hole 16 penetrating in the thickness direction. In this embodiment, the through-holes 16 are oval in shape, and five through-holes 16 are formed, but the shape and number are not limited. The through-holes 16 may be omitted, but the presence of the through-holes 16 in this embodiment makes it easier to generate plasma and facilitates the creation of a power supply circuit. Furthermore, contact with gas at the through-holes 16 enables plasma processing of the gas.

[0018] Upper-layer electrode 12 and lower-layer electrode 13 are formed of a conductive material, and may be a metal plate (including metal foil), conductive paint, conductive polymer, conductive film, etc. There are no particular limitations on the thickness of upper-layer electrode 12 and lower-layer electrode 13, but in order to provide a flexible, lightweight, and compact processing device, the thickness is preferably 5 μm to 1.0 mm, more preferably 5 μm to 0.2 mm, and even more preferably 5 μm to 0.1 mm, respectively.

[0019] The dielectric layer 11, the upper electrode 12, and the lower electrode 13 may be laminated without using an adhesive, or may be bonded with an adhesive. The adhesive is preferably a material that is durable against active substances generated in plasma. Examples of adhesives include epoxy, acrylic, urethane, phenol, urea, silicone, cyanoacrylate, rubber, and vinyl acetate adhesives. Among these, silicone adhesives, UV-curable epoxy adhesives, polyamide adhesives, and polyimide adhesives are preferred from the standpoint of durability, with silicone adhesives being more preferred. The thickness of the adhesive is preferably 0.01 to 0.2 mm, and more preferably 0.01 to 0.1 mm.

[0020] As shown in FIG. 3, the upper mask layer (mask layer) 14 and the lower mask layer (mask layer) 15 are members respectively disposed on the outside of the upper electrode 12 and the lower electrode 13. More specifically, the upper mask layer 14 is disposed on the upper surface of the upper electrode 12. The lower mask layer 15 is disposed on the lower surface of the lower electrode 13. The upper mask layer 14 and the lower mask layer 15 are each provided with a through hole 17. In this embodiment, the through holes 17 are oval in shape, and five through holes 17 are formed, but the shape and number are not limited. The through holes 17 may be omitted.

[0021] 2 and 3, through holes 17 have the same shape as through holes 16 and are connected to each other, but they do not necessarily have to be the same shape. Through through holes 16 and 17, dielectric layer 11 is exposed to the outside. In other words, the surface of dielectric layer 11 is exposed to the outside at multiple locations where through holes 16 and 17 are formed. In addition, hole walls (cross-sectional portions) 16a and 17a of through holes 16 and 17 are also exposed to the outside. When an AC voltage is applied between the upper electrode 12 and the lower electrode 13 sandwiching the dielectric layer 11, plasma is generated within the dielectric layer 11 sandwiched between the two electrode layers. Furthermore, plasma is also generated near the cross-sectional portions 16a of the electrode layer within the through-holes 16 and 17. When an AC voltage is applied between the two electrode layers, plasma is generally more likely to be generated from the protruding edges of the electrode layers than from the flat portions of the electrode layers. Therefore, in FIGS. 2 and 3, more plasma is likely to be generated near the cross-sectional portions 16a of the electrode layers within the through-holes 16 and 17 than inside the dielectric layer 11 between the two electrode layers. As a result, providing the through-holes 16 and 17 in the plasma generation unit 10 enables more effective plasma generation. While creating countless fine through-holes across the entire surface of the electrode layer ultimately results in a mesh-like structure for the electrode layer, it is also possible to use a mesh structure made of metal or other material as the electrode layer. Furthermore, when the mask layer is formed using a liquid resin or the like, the mask layer penetrates into areas where there are no electrodes and directly covers the dielectric, but in areas where the dielectric is exposed, as in this case, the material that makes up the mask layer functions as part of the dielectric and can also be used to protect the dielectric layer.

[0022] The upper mask layer 14 and the lower mask layer 15 are formed of an insulating material. The material for forming the mask layers is similar to that of the dielectric layer 11, and is preferably a material selected from glass, ceramics, and synthetic resins. However, to accommodate complex shapes such as those of this embodiment, a flexible material is preferable. Furthermore, the hardness of the upper mask layer 14 and the lower mask layer 15 is preferably equal to or less than that of the upper electrode 12 and the lower electrode 13. Although the plasma generation unit 10 can be difficult to handle if it is manufactured using a thin material, the provision of the upper mask layer 14 and the lower mask layer 15 improves ease of handling. Furthermore, the upper mask layer 14 and the lower mask layer 15 can protect the thin conductor from mechanical and physical shocks during manufacturing and use, as well as deterioration caused by the surrounding environment. They also provide mechanical protection against scratches that may occur during manufacturing. On the other hand, when considering that the plasma generating unit 10 will be installed on an object to be attached, it is preferable that the upper mask layer 14 and the lower mask layer 15 have a hardness that allows them to be easily installed along the object to be attached and also improves handling. Furthermore, by dividing the dielectric layer 11 into two, the upper and lower structures of the plasma generating unit 10 can be made symmetrical. Manufacturing can be easily achieved by assembling the upper and lower structures and bonding them together in the center. In this case, the dielectric layer 11 is divided into three layers: the upper layer, the lower layer, and the adhesive layer, but is electrically considered to be a single dielectric. The thicknesses of the upper mask layer 14 and the lower mask layer 15 are not particularly limited, but in order to provide a flexible, lightweight, and compact processing device, they are preferably 5 μm to 1.0 mm, more preferably 5 μm to 0.2 mm, and even more preferably 5 μm to 0.1 mm. The thicknesses of the upper mask layer 14 and the lower mask layer 15 may be set as appropriate, but in this embodiment they are formed to be larger than the thicknesses of the upper-layer electrode 12 and the lower-layer electrode 13.

[0023] The plasma generating unit 10 can be made very thin and flexible, which can lead to problems such as difficulty in handling during assembly. Furthermore, the upper electrode 12 and the lower electrode 13 are formed of conductive materials, such as conductive metals or conductive dielectrics. However, metals, for example, can be corroded by liquids or gases. Furthermore, the upper electrode 12 and the lower electrode 13 are oxidized by highly oxidizing gases and corroded by sulfuric acid or hydrochloric acid. Furthermore, if the upper electrode 12 and the lower electrode 13 are made of a resin-based conductive material, they may be deteriorated by humidity or acid. Furthermore, the plasma generating unit 10 is designed to be installed according to the shape of the object to which it is to be attached. However, if only the upper electrode 12 and the lower electrode 13 are used without the upper mask layer 14 and the lower mask layer 15, problems such as wrinkles in the metal constituting the electrodes or gaps between the electrodes and the dielectric layer 11 can occur if the electrodes are made of thin metal. If gaps are formed between the upper layer electrode 12 and the lower layer electrode 13 and the dielectric layer 11, this may cause abnormal discharge. In this regard, according to this embodiment, the upper mask layer 14 and the lower mask layer 15 can protect the upper electrode 12 and the lower electrode 13, and the plasma generating unit 10 can be easily handled, improving workability and assembly. Furthermore, the provision of the upper mask layer 14 and the lower mask layer 15 allows installation on an object without forming wrinkles or gaps. Furthermore, when multiple pairs of electrodes are provided to form a multi-stage structure, the upper mask layer 14 and the lower mask layer 15 also serve as part of the dielectric that constitutes the barrier discharge, making it less likely that abnormal discharge will occur even if gaps are formed during installation. Depending on the situation, the same effect can be achieved with either the upper or lower mask layer.

[0024] The outer edges of upper-layer electrode 12 and lower-layer electrode 13 may be sealed with an insulator (not shown) to prevent deterioration over time due to exposure to the outside world and to prevent discharge from occurring through the outer edges other than through-hole 16. When a synthetic resin or the like is used as the mask layer, this effect is achieved because it thinly extends to the outer edges of dielectric layer 11 in addition to the outer edges of upper-layer electrode 12 and lower-layer electrode 13. Similarly, the outer edges of the upper mask layer 14 and the lower mask layer 15 may be sealed with an insulator (not shown) to prevent their outer edges from being exposed to the outside world and reacting with external substances to deteriorate over time, and to prevent discharge from occurring through the outer edges other than the through holes 17.

[0025] When the longitudinal direction of the through holes 16, 17 is parallel to the gas flow direction, the resistance to the gas flow is small and the gas flows smoothly. On the other hand, when the longitudinal direction of the through holes 16, 17 is perpendicular to the gas flow direction, the resistance to the gas flow is large, the gas flow is disturbed, and the gas is agitated.

[0026] The shape, number, and orientation of the through-holes 16 and 17 relative to the gas flow can be selected appropriately depending on the purpose of the plasma processing, the effect of the plasma processing, and other factors. The through-holes may have different shapes on the front and back sides of the plasma generating unit 10. Alternatively, through-holes may be provided on the front side of the plasma generating unit 10, while no through-holes are provided on the back side. Although the through-holes are shown as oval in this example, this shape is not required. Round, elliptical, rectangular, triangular, and other shapes are also acceptable. However, shapes with sharp corners tend to concentrate the electric field, so rounded corners are more appropriate. A similar effect can also be achieved with a structure with larger through-holes, such as a mesh-like shape. While the figure shows five through-holes, there is no limit to the number. Multiple through-holes may be arranged vertically or horizontally. Furthermore, through-holes shaped like a company logo or initials can be provided to expose the plasma area, allowing for use as a display.

[0027] <First Modification of Plasma Generation Unit> 4 is a perspective view for explaining a plasma generating unit according to a first modified example. The plasma generating unit 10A according to the first modified example differs from the basic structure described above in that it does not have an upper mask layer 14. As in the plasma generating unit according to the first modified example, the mask layer may be provided only on one side of the plasma generating unit 10A.

[0028] <Second Modification of Plasma Generation Unit> FIG. 5 is a perspective view illustrating a plasma generating unit according to a second modified example. The plasma generating unit 10B according to the second modified example differs from the basic structure described above in that it does not include the upper mask layer 14 and the lower mask layer 15. The upper mask layer 14 and the lower mask layer 15 may be omitted, as in the plasma generating unit 10B according to the second modified example. That is, by configuring the plasma generating unit 10B with only the dielectric layer 11, the upper electrode 12, and the lower electrode 13, it is possible to further reduce the size and the number of parts. Furthermore, if processes for manufacturing printed circuit boards, semiconductor ICs, etc. can be used to manufacture this plasma generating unit, process steps can be omitted, thereby reducing product costs.

[0029] Furthermore, as in the first and second modified examples, by omitting either or both of the upper mask layer 14 and the lower mask layer 15, the overall thickness can be reduced and flexibility can be increased, which is convenient when creating an ultra-compact plasma generation device.

[0030] <Third Modification of Plasma Generation Unit> FIG. 6 is a perspective view illustrating a plasma generation unit according to a third modification. The plasma generation unit 10C according to the third modification differs from the basic structure described above in that an air layer 18 is provided below the dielectric layer 11C. If air is considered a dielectric with a relative dielectric constant of 1 and the combined air and dielectric layer 11C are considered a single dielectric, the structure can be considered identical to the basic structure shown in FIG. 2. The composite relative dielectric constant (or dielectric constant) can be calculated from the respective relative dielectric constants (or dielectric constants) and thicknesses. The plasma generation unit 10C according to the third modification includes a dielectric layer 11C, an upper electrode 12, a lower electrode 13, an upper mask layer 14, a lower mask layer 15, and an air layer 18. The air layer 18 is provided between the dielectric layer 11C and the lower electrode 13. In the third modification, three surfaces can come into contact with gas: the air layer 18 between the upper electrode 12 and the lower electrode 13, the back surface of the lower electrode 13, and the back surface of the upper electrode 12. The back surface here refers to the surface opposite to the air layer 18. This improves the plasma utilization efficiency compared to when only the air layer 18 is used, and allows for plasma processing of a larger amount of gas.

[0031] <Fourth Modification of Plasma Generation Unit> FIG. 7 is a cross-sectional view illustrating a plasma generating unit according to a fourth modification. The plasma generating unit 10D according to the fourth modification differs from the third modification in that it does not include an upper mask layer 14. As with the third modification, if air is considered a dielectric with a dielectric constant of 1 and the dielectric layer 11C and the resulting air layer are considered a single dielectric, the resulting structure can be considered identical to the basic structure shown in FIG. 2. The composite dielectric constant (or permittivity) can be calculated from the respective permittivity (or permittivity) and thickness. The plasma generating unit 10D includes a dielectric layer 11C, an upper electrode 12, a lower electrode 13, a lower mask layer 15, and an air layer 18. As in the fourth modification, the air layer 18 may be provided between the dielectric layer 11C and the lower electrode 13, while the upper mask layer may be omitted. This configuration can achieve substantially the same effects as the third modification while reducing the number of components. Furthermore, when this electrode is fabricated using a process for manufacturing printed circuit boards or semiconductor ICs, a process step can be omitted, thereby reducing costs.

[0032] <Fifth Modification of Plasma Generation Unit> FIG. 8 is a cross-sectional view illustrating a plasma generating unit according to a fifth modification. The plasma generating unit 10E according to the fifth modification differs from the third modification in that it does not include an upper mask layer 14 and a lower mask layer 15. The plasma generating unit 10E also includes a dielectric layer 11Cb on the lower surface of the lower electrode 13. The plasma generating unit 10E includes dielectric layers 11Ca and 11Cb, an upper electrode 12, and a lower electrode 13. The dielectric layer 11Cb on the lower surface of the lower electrode 13 is used to support the lower electrode 13. As in the fifth modification, the upper and lower mask layers may be omitted while providing an air layer 18 between the dielectric layer 11Ca and the lower electrode 13. This configuration can achieve substantially the same effects as the third modification while reducing the number of components. In this way, the structure constituting the upper electrode 12 and the structure constituting the lower electrode 13 can have the same configuration. Furthermore, when this electrode is fabricated using a process for manufacturing a printed circuit board or a semiconductor IC, a process step can be omitted, thereby reducing costs. Furthermore, since there is less material in the thickness direction, flexibility can be improved.

[0033] The upper layer dielectric 11Ca and the air layer 18 function as a single dielectric. This dielectric constant can be calculated from the relative permittivity (or dielectric constant) and thickness of the upper layer 11Ca, and, if air is used as the gas, the relative permittivity (or dielectric constant) of the air and the thickness of the air layer 18. The lower layer dielectric 11Cb plays almost no role in plasma generation. However, this structure allows the upper layer electrode 12 and the lower layer electrode 13 to have the same configuration. This reduces manufacturing costs.

[0034] <Sixth Modification of Plasma Generation Unit> 9 is a cross-sectional view illustrating a plasma generating unit according to a sixth modified example. The plasma generating unit 10F according to the sixth modified example includes, from top to bottom, an air layer 18, an upper electrode 12, a dielectric layer 11Ca, an air layer 18, a lower electrode 13, a dielectric layer 11Cb, an air layer 18, an upper electrode 12, a dielectric layer 11Ca, an air layer 18, a lower electrode 13, and a dielectric layer 11Cb. In other words, the plasma generating unit 10F according to the fifth modified example is configured by stacking two plasma generating units 10E according to the fifth modified example in the thickness direction. The ends of the dielectric layers 11Ca and 11Cb are supported by a box-shaped housing 21F.

[0035] Inside the housing 21F, basic units in which an upper-layer electrode 12 is laminated only on one side (top surface) of a dielectric layer 11Ca and basic units in which a lower-layer electrode 13 is laminated only on one side (top surface) of a dielectric layer 11Cb are alternately arranged with an air layer (gas inlet layer) 18 between them. As a result, electrodes of opposite polarity are alternately laminated, but if a space in which plasma is not generated is desired, the electrodes do not need to be alternately arranged. By designing a space in which plasma is not generated in this way, it is possible to place a sensor, wiring, or other circuits between them. An air layer 18 is formed between each of the electrode layers adjacent in the vertical direction.

[0036] According to this modification, the plasma generating section 10F can be easily formed simply by stacking basic units each composed of a dielectric layer and an electrode layer (upper electrode 12 or lower electrode 13) at intervals. Furthermore, since plasma can be generated in multiple air layers 18, plasma can be generated efficiently in a small space. Furthermore, since no separate components such as spacers are required to space the basic units, multi-stage construction is easily possible, reducing manufacturing costs and shortening development time. Since the number of stacked electrodes can be freely changed, the amount of contact between plasma and gas can be controlled, and the contact area between plasma and gas can be easily changed, which has the advantage of easily constructing devices with different processing capacities.

[0037] The plasma generating unit 10 of this embodiment is manufactured by laminating materials such as electrode layers 12 and 13, dielectric layer 11, and mask layers 14 and 15. Methods for laminating each layer include known methods such as pressure bonding, thermocompression bonding, and adhesive application, and can be appropriately selected and used. Methods for forming through holes in the electrode layers 12 and 13 and mask layers 14 and 15 include known methods such as punching and etching, and can be appropriately selected and used.

[0038] The power supply unit (not shown) of this embodiment applies an AC voltage to the pair of electrode layers of the plasma generating unit 10. There are no particular restrictions on the specific contents of the power supply unit, and any known power supply device can be used as long as it can apply an AC voltage of a predetermined voltage at a predetermined frequency to the two electrode layers. The frequency of the AC voltage is preferably 50 Hz to 30 MHz, and more preferably 50 Hz to 100 kHz. The AC voltage is preferably 0.1 to 50 kV, and more preferably 0.2 to 10 kV.

[0039] In plasma-treated air, the active species generated by the plasma kill or inactivate microorganisms present in the air and decompose chemical substances, so by treating the air with plasma, it is possible to sterilize and deodorize the air. Furthermore, active species remain in the plasma-treated air. Therefore, by spraying the plasma-treated air onto an object, microorganisms present in the object are killed or inactivated, and chemical substances are decomposed, thereby sterilizing and deodorizing the object.

[0040] First Embodiment Next, a lighting device according to a first embodiment of the present invention will be described. 10 is a schematic cross-sectional view showing an illumination device according to the first embodiment. An illumination device 30 of the first embodiment basically includes an illumination element 23, an illumination element cover 22, and a base portion 24. The lighting element (light-emitting element) 23 is not particularly limited, and examples include an LED lamp (LED element, LED package, LED chip), a fluorescent lamp (filament), an incandescent lamp (filament), a halogen lamp (filament), a mercury lamp (electrode), and a sodium lamp (electrode). The lighting element cover 22, also called a light bulb cover or globe, protects the lighting element 23 from the outside world. The lighting element cover 22 is made of a transparent or translucent material and serves to emit and diffuse light to the outside. The lighting element cover 22 is usually made of glass or resin, which has excellent transparency, airtightness, and heat resistance. The base 24 is a part formed with screws and the like for setting the lighting device 30 in the socket. The lighting device 30 receives the power required for lighting from the outside through the base 24.

[0041] The space defined by the lighting element cover 22 and the base 24 typically contains not only the lighting element 23, but also a lighting circuit, a mounting board (drive circuit) for the lighting element 23, a heat sink, a reflector, a lens, a light guide plate, a fluorescent screen, etc. Furthermore, a power supply unit that applies an AC voltage to the electrode layer of the plasma generation unit 50 (described later) can be installed in the space. Also, various gases may be sealed in the space. The lighting element cover 22 may have various shapes, such as a bulb type, a straight tube type, a round type, a compact type, etc., but is not particularly limited to these. Fig. 10 shows a typical bulb type lighting device 30. In addition, a mounting board (drive circuit) for the lighting element 23 and a power supply unit that applies AC voltage for the plasma generator can also be incorporated into the base 24.

[0042] FIG. 10 shows a configuration in which a plasma generating unit 50 is formed on a portion of the lighting element cover 22. The plasma generating unit 50 is composed of an upper mask layer 14, an upper-layer electrode 12, a dielectric layer 11, the lighting element cover 22, and a lower-layer electrode 13. The lighting element cover 22 is usually made of glass or resin, but here, together with the dielectric layer 11, it forms the dielectric layer of the plasma generating unit 50. The material constituting the dielectric layer 11 is preferably a material that is resistant to plasma. Furthermore, the dielectric layer 11 can be a single layer or multiple layers. Furthermore, an air layer may be used as the dielectric layer 11. Furthermore, through holes (not shown) can be provided in the upper mask layer 14, the upper-layer electrode 12, and the lower-layer electrode 13.

[0043] Although not shown, the power supply and electric cable that apply AC voltage to the upper electrode 12 and the lower electrode 13 are installed in the space defined by the lighting element cover 22 and the base 24, and power is supplied from the outside through the base 24. Therefore, by inserting and setting the base 24 of the lighting device 30 into a socket connected to an external electric light line, power is supplied not only to the lighting element 23 but also to the plasma generation unit. As a result, the lighting device 30 not only functions as a lighting device by lighting the lighting element 23, but also functions as a plasma treatment device that plasma-treats the air around the lighting device 30 with plasma generated from the plasma generation unit 50.

[0044] When lighting element 23 is lit, heat is generated, causing the temperature of lighting device 30 to rise. As a result, the air around lighting device 30 is also heated, creating an air flow that causes the surrounding air to rise. Therefore, the air that has been plasma-treated by plasma generating unit 50 travels along this air flow and is diffused, thereby sterilizing or deodorizing the air around lighting device 30.

[0045] Of the multiple layers constituting the plasma generating unit 50, each layer except for the lighting element cover 22 can be formed using a flexible material. Therefore, the plasma generating unit 50 as a whole can be installed on the surface of the lighting element cover 22 as an integral laminate body in close contact with the surface.

[0046] By providing the upper mask layer 14, it is possible to provide safety protection by preventing direct contact of human hands with the upper electrode 12 to which a high voltage is applied. Also, by making the upper electrode 12, which is likely to be touched by human hands, the ground side, safety can be further improved. Furthermore, as will be described later, a protective cover may be provided above the plasma generation unit 50 with a gap therebetween, if necessary.

[0047] Since the lighting device 30 is a device that emits light rays emitted by the lighting elements 23 to the surroundings through the lighting element cover 22, it is preferable that the plasma generation unit 50 installed on the lighting element cover 22 be as transparent as possible and transmit the light rays. It is preferable that the materials forming the electrode layer, dielectric layer, and mask layer that make up the plasma generation unit 50 are selected from materials with excellent transparency when designing and manufacturing the unit.

[0048] Although FIG. 10 shows only one plasma generating unit 50 on the lighting element cover 22, the number of plasma generating units 50 is not limited to one, and multiple plasma generating units 50 may be installed on the lighting element cover 22. Furthermore, the plasma generating units 50 may be arranged in a ring shape so as to surround the lighting element cover 22. Furthermore, since the plasma generating units 50 can be manufactured in a thin and flexible form, the installation position, dimensions, and shape of the plasma generating units 50 can be freely designed and installed as needed. However, if the transparency of the plasma generating units 50 is poor, restrictions will naturally arise on the number, installation position, dimensions, and shape of the plasma generating units 50.

[0049] Second Embodiment Fig. 11 is a schematic cross-sectional view of a lighting device according to the second embodiment. Fig. 11 shows a configuration in which a plasma generating section 51 is formed on a portion of the lighting element cover 22. The plasma generating section 51 is composed of an upper mask layer 14, an upper-layer electrode 12, a dielectric layer 11, a lower-layer electrode 13, and a lower mask layer 15. The upper mask layer 14, the upper-layer electrode 12, the lower-layer electrode 13, and the lower mask layer 15 may be provided with through-holes (not shown).

[0050] In the plasma generating unit 50 of Fig. 10, the lower layer electrode 13 is formed on the inner surface of the lighting element cover 22. On the other hand, in the plasma generating unit 51 of Fig. 11, all layers are formed on the outer surface of the lighting element cover 22, so that the plasma generating unit 51 can be easily installed on the lighting element cover 22. The upper mask layer 14 and the lower mask layer 15 may not be provided if necessary.

[0051] It is preferable to install a connection part or an electrical wire connector between the plasma generating unit 51 and the lighting element cover 22 in such a way that the plasma generating unit 51 can be detached from the lighting element cover 22, as this makes it easy to replace as needed in the event of a malfunction, etc. The rest of the description is the same as that of the first embodiment, so the description will be omitted.

[0052] Third Embodiment Fig. 12 is a schematic cross-sectional view of an illumination device according to a third embodiment. Unlike Figs. 10 and 11, Fig. 12 shows a cross-sectional view of a straight-tube type (so-called fluorescent lamp type) illumination device 40 having a long, cylindrical glass tube. Bases for supplying power to the illumination device 40 are not shown because they are installed at both ends of the long glass tube. The illumination element 23 has a long shape that follows the long glass tube.

[0053] Figure 12 shows a configuration in which a plasma generating unit 52 is formed on a portion of the lighting element cover 22. The plasma generating unit 52 is composed of an upper mask layer 14, an upper electrode 12, a dielectric layer 11, a lower electrode 13, and a lower mask layer 15. It has the same configuration as the plasma generating unit 51 in Figure 11, but like the plasma generating unit 50 in Figure 10, the lower electrode 13 may be formed inside the lighting element cover 22. It is preferable to install a connection part or electric wire connector between the plasma generating unit 52 and the lighting element cover 22, as this makes it easy to replace the plasma generating unit as needed in the event of a malfunction, etc. The rest of the description is the same as that of the first and second embodiments, so the description will be omitted.

[0054] <Fourth embodiment> Fig. 13 is a schematic cross-sectional view of a lighting device according to a fourth embodiment, which shows a bulb-type lighting device 32 (Figs. 14 to 16 also show bulb-type lighting devices). 13 shows an embodiment in which a plasma generating unit 53 and a protective cover 25 are formed on a part of the lighting element cover 22. The configuration of the plasma generating unit 52 is similar to that of the plasma generating unit 51 in FIG.

[0055] The protective cover 25 is installed for safety reasons and to prevent fine dust and dirt from entering the plasma generating unit 53. The protective cover 25 may have gaps around it to allow ambient air to enter, or a filter may be installed to prevent dust from entering. The lighting element cover 22 of the lighting device 32 may be provided with a status indicator 27 (such as an LED lamp) that displays the operating status of the plasma generating unit 53, the power supply unit, the lighting element 23, and the like. If a connection part or an electric wire connector is provided between the plasma generating part 53 and the lighting element cover 22, it becomes easy to replace it as needed in case of a malfunction, etc., and this is preferable. The rest of the description is the same as that of the first to third embodiments, so the description will be omitted.

[0056] Fifth Embodiment Fig. 14 is a schematic cross-sectional view of a lighting device according to a fifth embodiment. Fig. 14 shows a lighting device 33 in which a plasma generating unit 54 is formed on a part of the inner surface of the lighting element cover 22. The configuration of the plasma generating unit 54 is similar to the configurations of the plasma generating units 51 and 53 in Figs. 11 and 13.

[0057] Depending on the installation direction of the lighting device 33, for example, as shown in FIG. 14, when the base 24 is positioned downward, air taken into the lighting device cover 22 through the vent 26a provided at the bottom of the lighting device cover 22 is plasma-treated by the plasma generating unit 54, heated by the heat generated by the lighting elements 23, creating a convection air flow, and released through the vent 26b. On the other hand, when the base 24 is positioned upward, air is convection-driven in the opposite direction to the above, and the air taken in through the vent 26b is plasma-treated by the plasma generating unit 54, heated by the heat generated by the lighting elements 23, and released through the vent 26a. Furthermore, the heat generated by the lighting elements 23 increases the temperature of the lighting device cover 22, warming the air around the lighting device cover 22 and creating an upward air flow, allowing the plasma-treated air to diffuse to the surrounding area. As a result, the air around the lighting device 33 can be sterilized or deodorized.

[0058] The number, position and shape of the ventilation holes 26 can be freely set as needed. A blower (not shown) may be installed in the lighting device 33 to forcibly create an air flow that draws air into the lighting element cover 22, processes it in plasma, and then releases it into the space outside the lighting element cover 22. Examples of blowers include fans, blowers, and pumps. The installation position, number, dimensions, and shape of the blowers are not limited and can be freely selected. Also, an ultrasonic generator may be installed inside the lighting element cover 22 to promote the diffusion of the plasma-treated air inside the lighting element cover 22. Also, to suppress the generation of ozone, which is a by-product, an ultraviolet light-emitting element may be installed in the location where plasma is generated, such as inside the lighting element cover 22.

[0059] Through holes may be formed in the lower mask layer 15 and the lower electrode 13 as needed. Furthermore, a mesh structure with numerous through holes may be used as the lower electrode 13. The upper electrode 12 does not necessarily need to have through holes, but may have through holes or a mesh structure in order to facilitate plasma generation, reduce costs by reducing the amount of metal, or increase light transmittance. The rest of the description is the same as that of the above embodiment, so the description will be omitted.

[0060] Sixth Embodiment Fig. 15 is a schematic cross-sectional view of a lighting device according to a sixth embodiment. Fig. 15 shows a lighting device 34 in which a lighting element cover 22 is used as a dielectric layer. That is, a plasma generation section 55 of the lighting device 34 is composed of an upper mask layer 14 and an upper electrode 12 on the outer surface of the lighting element cover 22, the lighting element cover 22 as a dielectric layer, and a lower electrode 13 and a lower mask layer 15 on the inner surface of the lighting element cover 22.

[0061] If only a portion of the lighting element cover 22 on which the plasma generating unit 55 is formed is formed in a detachable manner, the plasma generating unit 55 can be easily replaced by removing only that portion as needed. The rest of the description is the same as that of the above embodiment, so the description will be omitted.

[0062] Seventh Embodiment Fig. 16 is a schematic cross-sectional view of a lighting device according to a seventh embodiment. Fig. 16 shows a lighting device 35 having a plasma generation unit 56 configured by adding a dielectric layer 11 to the configuration of the plasma generation unit 55 shown in Fig. 15.

[0063] Although Figure 16 shows a configuration in which one dielectric layer 11 is added to the outer surface of the lighting element cover 22, multiple additional dielectric layers can be provided, and further, they may be provided on the inside, outside, or both the inside and outside of the lighting element cover 22. The rest of the description is the same as that of the above embodiment, so the description will be omitted. [Explanation of symbols]

[0064] 10 Plasma generation unit 11 Dielectric layer 12 Upper layer electrode (electrode layer) 13 Lower electrode (electrode layer) 14 Upper mask layer (mask layer) 15 Lower mask layer (mask layer) 22 Lighting element cover 23 Lighting elements 24 Cap part 25 Protective cover 26 Ventilation holes 30 Lighting equipment 50 Plasma generation unit

Claims

1. A lighting element; a lighting element cover for protecting the lighting element; a plasma generating unit that has a dielectric layer and a pair of electrode layers provided on both sides of the dielectric layer and generates plasma; a power supply unit that applies an AC voltage to the pair of electrode layers, A lighting device characterized in that the plasma generating unit is installed on the lighting element cover.

2. The lighting device according to claim 1 , wherein the electrode layer has a through-hole penetrating therethrough in a thickness direction.

3. 3. The lighting device according to claim 1, wherein the plasma generating portion is flexible.

4. 3. The lighting device according to claim 1, wherein the plasma generating section has a mask layer on the outside of at least one of the pair of electrode layers.

5. 3. The lighting device according to claim 1, wherein the plasma generating portion is transparent.

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