JP2017016966A - Microwave electrodeless lamp and light irradiation device employing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mercury-free type microwave electrodeless lamp capable of radiating an ultraviolet ray in a UV-A range with a stable emission intensity without using mercury as a luminescent material, and a light irradiation device employing the same.SOLUTION: The microwave electrodeless lamp which emits light by receiving microwave energy comprises a discharge container, and a rare gas and a luminescent material encapsulated in the discharge container. The luminescent material contains iron iodide, cobalt iodide, zinc and nickel. An encapsulation density of the cobalt iodide is 3.7 to 9.4 μmol/cc. A ratio of an encapsulation density of the cobalt iodide with respect to an encapsulation density of the iron iodide is 0.97 to 93.60. An encapsulation intensity of the zinc is 2.8 to 3.8 μmol/cc, and an encapsulation density of the nickel is 12.0 to 68.0 μmol/cc.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a microwave electrodeless microwave electrodeless lamp and a light irradiation apparatus using the same.

  In recent years, a microwave electrodeless lamp has been developed as a discharge lamp that emits visible light or ultraviolet light. A light irradiation apparatus equipped with a microwave electrodeless lamp typically includes a microwave oscillator, a microwave cavity, and an electrodeless lamp that is a discharge tube (light emitting tube). The electrodeless lamp is detachably supported in the microwave cavity. The microwave cavity is provided with a reflecting mirror for guiding visible light or ultraviolet light from the electrodeless lamp to the light exit. The light exit is provided with a conductive mesh that is impermeable to microwaves but transmissive to visible light or ultraviolet light.

  The discharge tube is filled with a starting rare gas and a luminescent material. By appropriately selecting the luminescent substance, visible light or ultraviolet light having a desired wavelength can be obtained. Ultraviolet rays are divided into a UV-A region having a wavelength of 315 to 400 nm, a UV-B region having a wavelength of 280 to 315 nm, and a UV-C region having a wavelength of 200 to 280 nm. Ultraviolet rays in the UV-A region are used for curing treatment of paints, resins, and the like. Ultraviolet rays in the UV-C region are used for sterilization.

  Patent Document 1 describes an example of an electrodeless lamp in which mercury iodide and iron are enclosed. Patent Document 2 describes an example of a mercury-free electrodeless lamp. As the luminescent material, mercury, halogen, iron, nickel, cobalt, palladium, or the like is used.

JP-A-6-13052 (Patent No. 3496033) JP 57-172650 A

  In recent years, there is an increasing demand for ultraviolet rays having a wavelength of 315 to 400 nm (UV-A region) used for curing treatment of paints, resins, and the like. In an electrodeless discharge lamp that generates ultraviolet rays in the UV-A region, conventionally, mercury is used as a luminescent material. In recent years, mercury tends to avoid its use as an environmentally hazardous substance. On the other hand, there is an increasing demand for a light irradiation device that stably emits ultraviolet rays in the UV-A region.

  An object of the present invention is to provide a mercury-free microwave electrodeless lamp capable of stably emitting ultraviolet light emission intensity in the UV-A region without using mercury as a light-emitting substance, and a light irradiation apparatus using the same Is to provide.

According to an embodiment of the present invention, in a microwave electrodeless lamp that emits light by receiving microwave energy,
A discharge vessel and a rare gas and a luminescent material enclosed in the discharge vessel,
The light emitting material includes iron iodide, cobalt iodide, zinc, and nickel,
The cobalt iodide has an encapsulation density of 3.7 to 9.4 μmol / cc,
The ratio of the cobalt iodide encapsulation density to the iron iodide encapsulation density is 0.97 to 93.60,
The zinc packing density is 2.8 to 3.8 μmol / cc,
The enclosure density of the nickel is 12.0 to 68.0 μmol / cc.

  According to an embodiment of the present invention, in the microwave electrodeless lamp, the sum of the iron iodide encapsulation density and the cobalt iodide encapsulation density may be 9.0 to 10.0 μmol / cc.

According to an embodiment of the present invention, in a light irradiation apparatus having a microwave oscillator, an antenna attached to the microwave oscillator, and an electrodeless lamp that emits light by receiving microwave energy from the antenna,
The electrodeless lamp has a discharge vessel in which a rare gas and a luminescent material are enclosed,
The light emitting material includes iron iodide, cobalt iodide, zinc, and nickel,
The cobalt iodide has an encapsulation density of 3.7 to 9.4 μmol / cc,
The zinc packing density is 2.8 to 3.8 μmol / cc,
The enclosure density of the nickel is 12.0 to 68.0 μmol / cc.

  According to the embodiment of the present invention, in the light irradiation apparatus, the sum of the iron iodide encapsulation density and the cobalt iodide encapsulation density may be 9.0 to 10.0 μmol / cc.

  According to the present invention, a mercury-free microwave electrodeless lamp capable of stably radiating ultraviolet light emission intensity in the UV-A region without using mercury as a light-emitting substance, and a light irradiation apparatus using the same Can be provided.

FIG. 1A is a schematic perspective view showing an example of a light irradiation apparatus using the microwave electrodeless lamp according to the present embodiment. FIG. 1B is a schematic front view of the light irradiation device of FIG. 1A as viewed from the front. FIG. 2 is a diagram illustrating a cross-sectional configuration of the front side inside of the housing of the light irradiation apparatus according to the present embodiment. FIG. 3 is a diagram illustrating an example of an electrodeless lamp according to the present embodiment. FIG. 4 is a diagram illustrating dimensions of an example of the electrodeless lamp according to the present embodiment. FIG. 5 shows an example of the results of an electrodeless lamp lighting experiment conducted by the inventors of the present invention, and shows the relationship between the ratio of the cobalt iodide encapsulation density to the iron iodide encapsulation density and the ultraviolet (UV-A) emission intensity. It is a figure explaining. FIG. 6 shows an example of the results of an electrodeless lamp lighting experiment conducted by the inventor of the present application, and is a diagram for explaining the relationship between zinc encapsulation density (μmol / cc) and ultraviolet (UV-A) emission intensity. . FIG. 7 shows an example of the result of an electrodeless lamp lighting experiment conducted by the inventors of the present application, and is a diagram for explaining the relationship between nickel encapsulation density and ultraviolet (UV-A) emission intensity. FIG. 8 shows an example of a result of an electrodeless lamp lighting experiment conducted by the inventors of the present application, and is a diagram for explaining spectral characteristics of ultraviolet (UV-A) emission intensity with respect to nickel sealing density.

  Hereinafter, an electrodeless lamp according to the present invention and a light irradiation apparatus using the same will be described in detail with reference to the accompanying drawings. It should be noted that this embodiment is an exemplification and does not limit the present invention in any way.

  1A and 1B are diagrams illustrating an example of a light irradiation apparatus using a microwave electrodeless lamp according to the present embodiment. FIG. 1A is a perspective view of the light irradiation device 10. FIG. 1B is a schematic front view of the light irradiation device 10 of FIG. 1A as viewed from the front. As shown in the figure, the X axis is set along the lamp axis direction of the light irradiation device 10, the Z axis is set along the light emission direction (arrow direction) from the light irradiation device 10, and the Y axis is set in the direction perpendicular to the XZ plane. .

  The light irradiation device 10 has a rectangular housing 4, and a microwave oscillator 3 (not shown) is provided inside the rear side of the housing 4. The light irradiation device 10 further includes an antenna 8 attached to the microwave oscillator 3, an electrodeless lamp 12 that emits light upon receiving microwave energy from the antenna 8, and a reflection disposed along the axis of the electrodeless lamp 12. It has a mirror 14. A space surrounded by the reflecting mirror 14 forms a microwave cavity 5. The electrodeless lamp 12 is disposed in the microwave cavity 5.

  The light irradiation device 10 further includes a cooling air supply mechanism that cools the electrodeless lamp 12. The cooling air supply mechanism has a cooling air source (not shown) and a cooling air duct 6 (not shown in FIG. 1B) mounted on the upper side of the housing 4.

  A microwave indicates an electromagnetic wave having a wavelength of 1 m to 100 μm and a frequency of 300 MHz to 3 THz, and is the shortest wavelength region among radio waves. Examples of the microwave oscillator 3 include a circuit using a magnetron, a klystron, a traveling wave tube (TWT), a gyrotron, and a Gunn diode. In this embodiment, a magnetron is used as the microwave oscillator. A magnetron is a type of oscillation vacuum tube that generates powerful non-coherent microwaves. In familiar places, magnetrons are used in radar and microwave ovens. In this embodiment, a magnetron used in a microwave oven, preferably a commercial microwave oven, is used. Note that the microwave oven uses a frequency of 2,450 MHz, but this is not due to technical limitations but due to legal restrictions.

  FIG. 2 shows a cross-sectional configuration inside the front side of the housing 4 of the light irradiation apparatus 10 according to the present embodiment. Typically, the reflecting mirror 14 includes an ellipsoidal reflecting mirror for condensing on the irradiated surface, a parabolic reflecting mirror that applies parallel light to the irradiated surface, and the like. Both the ellipsoid and the paraboloid have at least one focal point. In the embodiment of FIG. 2, the reflecting mirror 14 is a saddle-type ellipsoidal reflecting mirror, the electrodeless lamp 12 is a straight tube type, and is arranged so that its central axis is located at the focal point of the ellipsoidal reflecting mirror. Note that the center (center axis) of the electrodeless lamp does not necessarily coincide with the focal position of the reflector, and the central portion of the lamp body is located at the position including the focal point in consideration of the positional error of the lamp. It only has to be arranged.

  A light exit 2 is formed on the front surface of the housing 4 of the reflecting mirror 14, and the light exit is covered with a conductive mesh 16. The conductive mesh 16 is impermeable to microwaves but is transmissive to irradiation light 18 from the microwave cavity, that is, visible light and ultraviolet rays.

  Microwaves generated from the microwave oscillator 3 are radiated through the antenna 8 and supplied to the microwave cavity 5 where a standing wave is formed. Plasma is excited inside the electrodeless lamp 12 disposed in the microwave cavity 5. Visible rays or ultraviolet rays radiated from the plasma are reflected from the reflecting mirror 14 as the irradiation light 18 or directly emitted toward the light exit 2 and pass through the conductive mesh 16 to be irradiated on the irradiated surface. The

  Cooling air 17 from a cooling air source (not shown) is supplied to the microwave cavity 5 through the cooling air duct 6 (FIG. 1A) and through the hole 14 </ b> A of the reflecting mirror 14. The cooling air 17 collides with the outer peripheral surface of the electrodeless lamp 12 and cools the electrodeless lamp 12.

  An example of a straight tube type electrodeless lamp according to the present embodiment will be described with reference to FIG. The electrodeless lamp 12 is a straight tube type having a cylindrical discharge vessel 12A, and has protrusions 12B at both ends thereof. The electrodeless lamp 12 is held in the microwave cavity by engaging the protrusions 12B on both ends of the discharge vessel with the engaging portions on the inner walls on both sides of the casing.

  When the magnetron is oscillated, microwave energy of 2,450 MHz is supplied to the microwave cavity 5 to form a standing wave. The microwave is combined with the discharge vessel 12A of the electrodeless lamp 12 to excite plasma inside. Visible light or ultraviolet light is emitted from the luminescent material.

When the electrodeless lamp 12 is turned on, two plasma regions 13 are formed inside the discharge vessel 12A as indicated by broken lines. The plasma region 13 forms a standing wave having an antinode 131 and nodes 132 on both sides thereof. The wavelength of this standing wave is λ = propagation speed / frequency = 2.99 × 10 ⁸ (m / s) /2.45 GHz≈123 mm. The length in the axial direction of the discharge vessel 12A of the electrodeless lamp is formed substantially equal to the length of one wavelength.

  The portion of the antinode 131 of the standing wave has a relatively high temperature and emits relatively strong light. This is called the high temperature region (hot zone) 12a, 12b. The portion of the standing wave node 132 is relatively cool and emits relatively weak light. This is called a low temperature region (cold zone) 12c, 12d, 12e. In the discharge vessel 12A, the standing wave is formed symmetrically. Therefore, the lowest temperature position in the center is at the center position in the axial direction of the discharge vessel 12A. In the low temperature regions 12c, 12d, and 12e, evaporation of the encapsulated material may be inhibited or reaggregation may occur. Therefore, the temperature distribution in the discharge vessel 12A of the electrodeless lamp 12 becomes non-uniform along the axial direction.

  An example of a straight tube type electrodeless lamp according to the present embodiment will be described with reference to FIG. The discharge vessel 12 </ b> A has a cylindrical portion 121. End portions 123 and 123 are formed on both sides of the cylindrical portion. The end portions 123 and 123 are formed in the low temperature regions 12d and 12e on both sides of the discharge vessel, and may be formed in a rotational curved surface shape such as a spherical shape or an elliptical spherical shape.

The dimension in the axial direction of the electrodeless lamp is L1, the dimension in the axial direction of the discharge vessel 12A is L, and the dimension in the axial direction of the protrusions 12B and 12B is Lt. L1 = L + 2Lt = 146-158 mm, L = 130-140 mm, Lt = 8.0-9.0 mm. The inner diameter of the cylindrical portion 121 is D ₁ , the outer diameter is D ₂ , the thickness is t, and the outer diameters of the protrusions 12B and 12B are Dt.

  The electrodeless lamp 12 is made of quartz glass. The discharge vessel 12A is formed of a sealed vessel made of quartz glass. The protrusions 12B and 12B are quartz glass rods. The discharge vessel 12A is filled with a starting rare gas and a luminescent material.

Below, the preliminary experiment which this inventor performed is demonstrated. First, the shape and dimensions of the discharge vessel 12A of the electrodeless lamp used in the preliminary experiment will be described. In the experiment, an electrodeless lamp shown in FIGS. 3 and 4 was used. The dimensions of the discharge vessel 12A are as follows. L1 = L + 2Lt = 155 mm, L = 138 mm, Lt = 8.5 mm, D ₂ = 11 mm, Dt = 3 mm. The thickness of the discharge vessel 12A was t = 1 mm. The internal volume of the discharge vessel 12A is 8.8 cc.

Next, the enclosure of the discharge vessel 12A used in the experiment will be described. As described above, in this embodiment, mercury, which is an environmentally hazardous substance, is not used as the luminescent substance. In the experiment, cobalt iodide (CoI ₂ ), iron iodide (FeI ₂ ), zinc (Zn), and nickel (Ni) were used as the luminescent materials. Argon gas of 1 to 10 Torr was sealed as a rare gas for starting. The input power of the electrodeless lamp was fixed at 1.4 kW, and the emission intensity at a wavelength of 315 to 400 nm (UV-A region) was measured.

First, cobalt iodide (CoI ₂ ) and iron iodide (FeI ₂ ) will be described. Cobalt (Co) and iron (Fe) are known to contribute to light emission in the UV-A region. In preliminary experiments conducted by the inventors of the present application, it was found that the emission intensity in the UV-A region increases as the encapsulation density of cobalt iodide (CoI ₂ ) increases. The enclosure density of cobalt iodide (CoI ₂ ) needs to be at least 3 μmol / cc. On the other hand, when the enclosure density of cobalt iodide (CoI ₂ ) exceeded 10 μmol / cc, it was confirmed that the startability was lowered. Furthermore, even if the encapsulation density of cobalt iodide (CoI ₂ ) is further increased, the emission intensity in the UV-A region does not increase further. From the above, the enclosure density of cobalt iodide (CoI ₂ ) is preferably 3 to 10 μmol / cc. Therefore, the inventors of the present application conducted an experiment to determine the optimum ratio of cobalt and iron. Below, the experiment which calculates | requires the optimal ratio of cobalt and iron is demonstrated.

Table 1 shows the luminescent material used in the experiment and the measurement result of the intensity of ultraviolet rays in the UV-A region, which is the experimental result. And the sum of the charging density of charging density and iron iodide of cobalt iodide _{(CoI 2) (FeI 2)} α, the ratio of the charging density of cobalt iodide for charging density of iron iodide (FeI ₂₎ (CoI ₂₎ Is β.
alpha = ratio of charging density of cobalt iodide (CoI ₂₎ of charging density and cobalt iodide for charging density of the sum beta = iron iodide in charging density of iron iodide _{(FeI 2) (FeI 2)} (CoI 2)

The first column is the experiment numbers T1 to T12, the second column is the packing density of cobalt iodide (CoI ₂ ), the third column is the packing density of iron iodide (FeI ₂ ), and the fourth column is the cobalt iodide. the sum of the charging density of charging density and iron iodide of _{(CoI 2) (FeI 2)} α, fifth column, the ratio of the charging density of cobalt iodide for charging density of iron iodide (FeI ₂₎ (CoI ₂₎ β, the sixth column is the enclosure density of zinc (Zn). The seventh column shows the intensity (mW / cm ² ) of ultraviolet rays in the UV-A region. In these experiment numbers T1 to T12, the zinc (Zn) encapsulation density (3.58 μmol / cc) and the encapsulation amount (2.0 mmg) were constant. The encapsulating density of zinc (Zn) will be described in detail later with reference to FIG.

As shown in Experiment No. T1 to T12, it was gradually changing the ratio of the charging density of cobalt iodide (CoI ₂₎ beta for charging density of iron iodide (FeI _2). For example, in the case of experiment number T1, the encapsulation density of cobalt iodide (CoI ₂ ) is zero, the encapsulation density of iron iodide (FeI ₂ ) is 9.00 μmol / cc, and the encapsulation amount is 23.8 mg. On the other hand, in the case of experiment number T12, the encapsulation density of cobalt iodide (CoI ₂ ) is 9.36 μmol / cc, the encapsulation amount is 25 mmg, and the encapsulation density of iron iodide (FeI ₂ ) is zero. However, in the experiment numbers T1 to T12, the sum α of the cobalt iodide (CoI ₂ ) encapsulation density and the iron iodide (FeI ₂ ) encapsulation density is substantially constant. That is, α = 9.00 to 9.66 μmol / cc.

FIG. 5 shows the measurement results of the intensity of ultraviolet rays in the UV-A region shown in the seventh column of Table 1. The horizontal axis shown in column 5 of Table 1 is the ratio of the charging density of cobalt iodide for charging density of iron iodide _{(FeI 2) (CoI 2)} β. The scale on the horizontal axis is a logarithmic scale. The vertical axis represents the emission intensity (mW / cm ² ) at a wavelength of 315 to 400 nm (UV-A region) shown in the seventh column of Table 1. In the graph of FIG. 5, a circled point indicates the emission intensity of experiment number T1, a square mark indicates the emission intensity of experiment numbers T2 to T11, and a triangle mark indicates the measured value of the emission intensity of experiment number T12. As shown in the figure, when the ratio β is smaller than 1, increasing the ratio β increases the intensity of ultraviolet rays in the UV-A region. However, when the ratio β exceeds 100, the intensity of ultraviolet rays in the UV-A region decreases.

The inventor of the present application has selected the emission intensity of 1111 mW / cm ² of the experiment number T12 represented by the triangle mark on the right end as the reference value of the emission intensity of the ultraviolet rays in the UV-A region. As described above, the luminescent material having the experiment number T12 does not contain iron iodide (FeI ₂ ) and contains only cobalt iodide (CoI ₂ ). The inventors of the present application set a value that is 10% larger than the emission intensity of Experiment No. T12, that is, 1222 mW / cm ² as a preferable target value. The broken line parallel to the horizontal axis in FIG. 5 represents the target value 1222 mW / cm ² of the ultraviolet light emission intensity in the UV-A region. As shown in Table 1, it was experiment numbers T4 to T10 that the intensity of ultraviolet rays in the UV-A region exceeded the target value of 1222 mW / cm ² . For Experiment No. T4, the ratio β of the charging density of cobalt iodide for charging density of iron iodide _{(FeI 2) (CoI 2)} , 0.97. For Experiment No. 10, the ratio of the charging density of cobalt iodide for charging density of iron iodide (FeI ₂₎ (CoI ₂₎ is 93.60. Emission intensity, to exceed the target value 1222mW / cm ^2, the ratio β of the charging density of cobalt iodide for charging density of iron iodide _{(FeI 2) (CoI 2)} , by a 0.97 to 93.60 That's fine.

As described above, according to the embodiment of the present invention, the ratio β of the cobalt iodide (CoI2) encapsulation density to the iron iodide (FeI2) encapsulation density is 0.97 to 93.60. Also, the enclosure density of cobalt iodide (CoI ₂ ) is 3.7 to 9.4 μmol / cc, and the sum α of the enclosure density of cobalt iodide (CoI ₂ ) and the enclosure density of iron iodide (FeI ₂ ) is Α = 9.0 to 10.0 μmol / cc.

  Next, zinc (Zn) will be described. Since zinc has a high vapor pressure, the impedance during lighting can be increased. In addition, microwave energy can be absorbed efficiently. Therefore, the plasma temperature can be raised and the emission intensity of iron and cobalt can be raised. In Experiment Nos. T1 to T12, the enclosure density of zinc (Zn) was 3.58 μmol / cc, that is, the enclosure quantity of zinc was 2.0 mg. The optimum enclosure density of zinc will be described below.

FIG. 6 shows the results of measuring the relationship between the zinc (Zn) sealed in the discharge vessel 12A of the electrodeless lamp and the emission intensity at a wavelength of 315 to 400 nm (UV-A region). The horizontal axis represents zinc (Zn) encapsulation density (μmol / cc), and the vertical axis represents emission intensity (mW / cm ² ) at a wavelength of 315 to 400 nm (UV-A region). The enclosure density of cobalt iodide (CoI ₂ ) is 4.49 μmol / cc, and the enclosure density of iron iodide (FeI ₂ ) is 4.62 μmol / cc. Also, charging density ratio β is 0.97 cobalt iodide for charging density of iron iodide _{(FeI 2) (CoI 2)} , charging density iodide cobalt iron iodide (FeI ₂₎ of (CoI ₂₎ The sum α of the encapsulation density is 9.11 μmol / cc. This corresponds to the experiment number T4 in Table 1, and corresponds to the fourth square point from the left of the graph of FIG.

The inventors of the present application set 1222 mW / cm ² as the target value of the emission intensity of ultraviolet rays in the UV-A region, as in the case of FIG. The broken line parallel to the horizontal axis in FIG. 6 represents the target value 1222 mW / cm ² of the emission intensity of ultraviolet rays in the UV-A region. As illustrated, in order to exceed the target value of 1222 mW / cm ² , the zinc (Zn) encapsulation density may be set to 2.8 to 3.8 μmol / cc.

  Below, nickel (Ni) is demonstrated. As described above, Patent Document 2 describes that nickel (Ni) is used as a luminescent substance in a mercury-free electrodeless lamp. Therefore, the inventors of the present application have conceived that nickel (Ni) is used in an mercury-free electrodeless lamp to improve the emission intensity of ultraviolet rays in the UV-A region. Below, the nickel enclosure experiment conducted by the inventors of the present application will be described in detail. In this nickel encapsulation experiment, nickel (Ni) alone was used as the luminescent material.

First, the shape and dimensions of the discharge vessel 12A of the electrodeless lamp used in the experiment will be described. In the experiment, an electrodeless lamp shown in FIGS. 3 and 4 was used. The dimensions of the discharge vessel 12A are as follows. L1 = L + 2Lt = 155 mm, L = 138 mm, Lt = 8.5 mm, D ₁ = 8 mm, Dt = 3 mm. The thickness of the discharge vessel 12A was t = 1 mm. The internal volume of the discharge vessel 12A was 8.54 cc.

Next, the enclosure of the discharge vessel 12A used in this nickel enclosure experiment will be described. In this embodiment, mercury that is an environmentally hazardous substance is not used. In the present embodiment as described above, encapsulation of charging density is 3.7~9.4μmol / cc of cobalt iodide (CoI _2), cobalt iodide for charging density of iron iodide (FeI ₂₎ (CoI ₂₎ The density ratio β is 0.97 to 93.60. Therefore, in this nickel enclosure experiment, the enclosure density of cobalt iodide (CoI ₂ ) was 6.74 μmol / cc, and the enclosure density of iron iodide (FeI ₂ ) was 2.35 μmol / cc. The ratio β of the charging density of cobalt iodide for charging density of iron iodide (FeI ₂₎ (CoI ₂₎ therefore 2.87.

  As described above, in this embodiment, the encapsulation density of zinc (Zn) is 2.8 to 3.8 μmol / cc. Therefore, in this nickel enclosure experiment, the enclosure density of zinc (Zn) was 3.58 μmol / cc. Argon gas of 5 Torr was enclosed as a rare gas for starting. The input power of the electrodeless lamp was 1.50 kW, and the emission intensity at a wavelength of 315 to 400 nm (UV-A region) was measured.

Table 2 shows the results of a nickel encapsulation experiment conducted by the inventors of the present application. The input power of the electrodeless lamp in this nickel enclosure experiment is about 1.50 kW. The first row of Table 2 is test numbers 1-8. The upper part of the second row of Table 2 is the nickel (Ni) encapsulation density (unit: μmol / cc), and the lower part is the nickel (Ni) encapsulation amount (unit: mg). The upper part of the third row of Table 2 shows the emission intensity (unit: mW / cm ² ) of ultraviolet rays in the UV-A region, and the lower part shows the relative value with respect to the value of test number 1 in terms of 100 fractions. In addition, the measured value of the upper stage of the 3rd line of Table 2 is those average values, when a some measured value is obtained.

  In the case of test number 1, the enclosure density and the amount of enclosure of nickel (Ni) are zero. In the case of test number 2, the enclosure density of nickel (Ni) is 7.98 μmol / cc) (4 mg). In the case of test number 3, the enclosure density of nickel (Ni) is 15.96 μmol / cc) (8 mg). In the case of test number 4, the enclosure density of nickel (Ni) is 31.92 μmol / cc) (16 mg). In the case of test number 5, the enclosure density of nickel (Ni) is 47.88 μmol / cc) (24 mg). In the case of test number 6, the enclosure density of nickel (Ni) is 63.87 μmol / cc) (32 mg). In the case of test number 7, the enclosure density of nickel (Ni) is 79.83 μmol / cc) (40 mg). In the case of test number 8, the enclosure density of nickel (Ni) is 95.80 μmol / cc) (48 mg).

FIG. 7 is a graph showing the relationship between the second row and the third row in Table 2. The horizontal axis represents the enclosure density of nickel (Ni) (unit: μmol / cc), and the vertical axis represents the emission intensity of ultraviolet rays in the UV-A region (unit: mW / cm ² ). The inventor of the present application was based on the ultraviolet light emission intensity in the UV-A region, that is, 1342 mW / cm ² in the case of test number 1, that is, when the nickel (Ni) encapsulation density and the encapsulation amount were zero. Furthermore, a value 10% higher than the reference value, that is, 1476 mW / cm ² was set as a preferable target value. In FIG. 7, a broken line parallel to the horizontal axis represents a preferable target value of 1476 mW / cm ² . As shown in the figure, in order for the emission intensity of ultraviolet rays in the UV-A region to exceed the target value of 1476 mW / cm ² , it can be said that the nickel (Ni) encapsulation density should be 12.0 to 68.0 μmol / cc. .

FIG. 8 shows the spectral characteristics of ultraviolet rays in the UV-A region, which are the results of the nickel encapsulation experiment shown in Table 2. The horizontal axis represents wavelength (unit: nm), and the vertical axis represents emission intensity of ultraviolet rays in the UV-A region (unit: μW / cm ² / nm). The input power of the electrodeless lamp is about 1.50 kW. The solid line graph is for test number 1. The dotted line graph is for test number 2. The short-chain line graph is for test number 3. The dashed line graph is for test number 4. The one-dot chain line graph is for test number 5. The two-dot chain line graph is for test number 6. The one-dot two-dot line graph is for test number 7. The thin dotted line graph is for test number 8.

  The following knowledge is obtained from the graph of FIG. The influence of the addition amount of nickel (Ni) on the emission intensity differs between the wavelength range of 330 to 365 nm and the wavelength range of 370 to 400 nm. That is, it can be seen that the emission intensity is remarkably improved by adding nickel (Ni) in the wavelength range of 330 to 365 nm. That is, in the wavelength range of 330 to 365 nm, the emission intensity is improved when the nickel (Ni) encapsulation density is increased, but the emission intensity cannot be expected to be improved when the nickel (Ni) encapsulation density is decreased. On the other hand, at a wavelength of 370 to 400 nm, the emission intensity decreases as the nickel (Ni) encapsulation density increases. Therefore, in order to stably emit the emission intensity of ultraviolet rays in the UV-A region, it is preferable to select the optimum range of nickel (Ni) encapsulation density.

The knowledge obtained from experiments conducted by the inventors of the present application and embodiments of the present invention are summarized below.
(1) In an experiment conducted by the inventor of the present application, iron iodide (FeI ₂ ), cobalt iodide (CoI ₂ ), and zinc (Zn) were used as a luminescent material. Furthermore, in order to improve the emission intensity of ultraviolet rays in the UV-A region, nickel (Ni) alone was added.
(2) As shown in FIG. 7, when nickel (Ni) is added, the emission intensity of ultraviolet rays in the UV-A region can be improved as compared with the case where nickel (Ni) is not added. In particular, when the enclosure density of nickel (Ni) is 12.0 to 68.0 μmol / cc, the emission intensity of ultraviolet rays in the UV-A region can be sufficiently improved. Therefore, in the case of an application using ultraviolet rays in the wavelength region of 315 to 365 nm, it is preferable to add nickel (Ni) as the light emitting substance.

  (3) However, when the enclosure density of nickel (Ni) exceeds 68.0 μmol / cc, it is not possible to expect a remarkable improvement in the emission intensity of ultraviolet rays in the UV-A region. As shown in FIG. 8, this is considered to be due to a decrease in emission intensity in the wavelength region of 370 to 400 nm. Similarly, when the enclosure density of nickel (Ni) is less than 12.0 μmol / cc, it is not possible to expect a remarkable improvement in the emission intensity of ultraviolet rays in the UV-A region. As shown in FIG. 8, this is considered to be due to a decrease in emission intensity in the wavelength range of 330 to 365 nm.

  (4) From the experiments conducted by the inventors of the present application, in the embodiment of the present invention, the light emitting material to be sealed in the microwave electrodeless lamp includes iron iodide, cobalt iodide, zinc, and nickel. The enclosure density of cobalt iodide is 3.7 to 9.4 μmol / cc, the ratio of the enclosure density of cobalt iodide to the enclosure density of iron iodide is 0.97 to 93.60, and the enclosure density of zinc is It is 2.8-3.8 micromol / cc, and the enclosure density of nickel is 12.0-68.0 micromol / cc. Furthermore, the sum of the iron iodide encapsulation density and the cobalt iodide encapsulation density is 9.0 to 10.0 μmol / cc.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited by these embodiments, and various modifications can be made within the scope of the invention described in the claims. This will be readily appreciated by those skilled in the art.

  In the present invention, a light irradiation apparatus equipped with a microwave electrodeless lamp can be suitably used for, for example, surface hardening treatment of a surface coated with ink, coating, or the like.

DESCRIPTION OF SYMBOLS 2 ... Light emission port, 3 ... Microwave oscillator, 4 ... Housing | casing, 5 ... Microwave cavity, 6 ... Cooling air duct, 8 ... Antenna, 10 ... Light irradiation apparatus, 12 ... Electrodeless lamp, 12A ... Discharge vessel , 12B ... projections, 12a, 12b ... high temperature region (hot zone), 12c, 12d, 12e ... low temperature region (cold zone), 13 ... plasma region, 14 ... reflector, 14A ... hole, 16 ... conductive mesh, 17 ... cooling air, 18 ... irradiation light, 121 ... cylindrical portion, 123 ... end, 131 ... belly, 132 ... node

Claims (4)

In microwave electrodeless lamps that emit light upon receiving microwave energy,
A discharge vessel and a rare gas and a luminescent material enclosed in the discharge vessel,
The light emitting material includes iron iodide, cobalt iodide, zinc, and nickel,
The cobalt iodide has an encapsulation density of 3.7 to 9.4 μmol / cc,
The ratio of the cobalt iodide encapsulation density to the iron iodide encapsulation density is 0.97 to 93.60,
The zinc packing density is 2.8 to 3.8 μmol / cc,
A microwave electrodeless lamp having an enclosure density of nickel of 12.0 to 68.0 μmol / cc. The microwave electrodeless lamp according to claim 1, wherein
The microwave electrodeless lamp, wherein a sum of the iron iodide encapsulation density and the cobalt iodide encapsulation density is 9.0 to 10.0 μmol / cc. In a light irradiation apparatus having a microwave oscillator, an antenna attached to the microwave oscillator, and an electrodeless lamp that emits light by receiving microwave energy from the antenna,
The electrodeless lamp has a discharge vessel in which a rare gas and a luminescent material are enclosed,
The light emitting material includes iron iodide, cobalt iodide, zinc, and nickel,
The cobalt iodide has an encapsulation density of 3.7 to 9.4 μmol / cc,
The zinc packing density is 2.8 to 3.8 μmol / cc,
The light irradiation apparatus, wherein the nickel sealing density is 12.0 to 68.0 μmol / cc. In the light irradiation apparatus of Claim 3,
The light irradiation apparatus, wherein the sum of the iron iodide encapsulation density and the cobalt iodide encapsulation density is 9.0 to 10.0 μmol / cc.

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