JP6112360B2 - Microwave electrodeless lamp and light irradiation device using the same - Google Patents

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.

  In the discharge tube, a starting rare gas or an inert gas and a luminescent material are enclosed. By appropriately selecting the luminescent substance, visible light or ultraviolet light having a desired wavelength can be obtained. Ultraviolet rays with a wavelength of 254 nm are used for sterilization, and ultraviolet rays with a wavelength of 315 to 400 nm (UV-A region) are used for curing treatment of paints, resins, and the like. As the luminescent material, mercury, iron, metal halide, or the like is used.

  Patent Document 1 discloses an example in which a magnetron is used as a microwave oscillator. Patent Document 2 describes that the amount of mercury, iron, halogen, or the like enclosed as a luminescent material is appropriately selected in order to increase the intensity of ultraviolet light having a wavelength of 350 to 450 nm and improve the lamp life. Patent Document 3 describes that the amount of mercury and iron enclosed as a luminescent material is appropriately selected in order to ensure lamp life and discharge stability. Patent Document 4 describes that the ratio of bromine and iodine is appropriately selected as the luminescent material in order to shorten the starting time.

Japanese Patent Publication No. 3-37277 Japanese Patent Publication No. 2-331459 JP-A-6-13052 (Patent No. 3496033) JP-B-1-45179

  In recent years, there has been a growing demand for a light irradiation apparatus that stably emits ultraviolet rays having high emission intensity. In particular, the 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 is increasing. Furthermore, mercury is generally used as the luminescent material, but there is a demand for reducing the amount of mercury used.

  An object of the present invention is to provide a microwave electrodeless lamp capable of stably radiating ultraviolet rays having a high emission intensity and at the same time reducing the amount of mercury used, and a light irradiation apparatus using the same.

According to the present invention, in a microwave electrodeless lamp that emits light upon receiving microwave energy, a tubular discharge vessel made of quartz glass, and a rare gas and a luminescent substance enclosed in the discharge vessel, The luminescent material contains 0.3 × 10 ⁻⁵ mol / cc to 1.4 × 10 ⁻⁵ mol / cc of mercury, and further contains iron iodide, iron bromide, and thallium iodide.

  According to the present embodiment, in the microwave electrodeless lamp, the discharge vessel is connected to a reduced diameter central portion, a tapered portion connected to both sides of the reduced diameter central portion, and an outer end of the tapered portion. A cylindrical portion, and an outer diameter of the reduced diameter central portion is smaller than an outer diameter of the cylindrical portion, and the reduced diameter central portion corresponds to a node of a standing wave in a plasma region generated by microwave energy. It may be formed at a position corresponding to the low temperature region formed in this way.

According to the present invention, in a light irradiation apparatus including 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 is ineffective. having a discharge vessel active gas emitting substance is enclosed, the luminescent material comprises mercury ^{0.7 × 10 -5 mol / cc~1.4 ×} 10 -5 mol / cc, further, iodide Iron, iron bromide, and thallium iodide may be included.

  ADVANTAGE OF THE INVENTION According to this invention, the microwave electrodeless lamp which can reduce the usage-amount of mercury simultaneously while radiating | emitting the ultraviolet-ray of high luminescence intensity stably, 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. 5A is a diagram illustrating the relationship between the amount of enclosed mercury and the ultraviolet (UV-A) emission intensity in the electrodeless lamp according to the present embodiment. FIG. 5B is a diagram for explaining a spectrum of ultraviolet rays (UV-A) in the electrodeless lamp according to the present embodiment. FIG. 6A is a diagram for explaining a stable discharge state of an electrodeless lamp by an experiment conducted by the inventor of the present application. FIG. 6B is a diagram for explaining an unstable discharge state of the electrodeless lamp according to an experiment conducted by the inventor of the present application.

  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, the evaporation of the encapsulated material may be inhibited or recondensation may occur. Therefore, the temperature distribution in the discharge vessel 12A of the electrodeless lamp 12 becomes non-uniform along the axial direction.

  With reference to FIG. 4, another example of the straight tube type electrodeless lamp according to the present embodiment will be described. The electrodeless lamp 12 according to this embodiment includes a cylindrical discharge vessel 12A and protrusions 12B and 12B on both sides. As shown in the figure, the discharge vessel 12A has a cylindrical reduced diameter central portion 122, tapered portions 124 on both sides thereof, and cylindrical portions 121 and 121 on the outer sides thereof. End portions 123 and 123 are formed outside the cylindrical portion. The reduced diameter central portion 122 is formed in the low temperature region 12c (FIG. 3) in the center of the discharge vessel, and the tapered portion 124 is formed between the reduced diameter central portion 122 and the cylindrical portions 121 and 121 so as to connect them. ing. The end portions 123 and 123 are formed in the low temperature regions 12d and 12e on both sides of the discharge vessel. Similar to both ends of the discharge vessel 12A of the conventional straight tube type electrodeless lamp, the end portions 123 and 123 are rotated in a spherical shape, an elliptical spherical shape, or the like. It may be formed in a curved surface shape.

  In the present embodiment, since the reduced diameter central portion 122 is formed in the low temperature region 12c at the center of the discharge vessel, the internal space becomes small in the central low temperature region 12c, and recondensation of the encapsulated material is avoided.

  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. The dimension in the axial direction of the reduced diameter central portion 122 is La, the dimension in the axial direction of the tapered portion 124 is Lb, and the dimension in the axial direction of the cylindrical portions 121 and 121 is Lc. L1 = L + 2Lt = 150 to 160 mm, L = 130 to 140 mm, and Lt = 8.0 to 9.0 mm. La = 15-25 mm, Lb = 15-25 mm, Lc = 30-40 mm.

  The outer diameter of the reduced diameter central portion 122 is Da, the outer diameter of the cylindrical portions 121 and 121 is Dc, and the outer diameter of the projecting portions 12B and 12B is Dt. The outer diameter Da of the reduced diameter central portion 122 is smaller than the outer diameter Dn of the discharge vessel 12A of the conventional straight tube type electrodeless lamp. That is, Dn> Da. The outer diameter Dc of the cylindrical portions 121 and 121 is equal to the outer diameter Dn of the discharge vessel 12A of the conventional straight tube type electrodeless lamp. That is, Dn = Da. The outer diameter of the inner end of the tapered portion 124 is equal to the outer diameter Da of the reduced diameter central portion 122, and the outer diameter of the outer end of the tapered portion 124 is equal to the outer diameter Dc of the cylindrical portions 121 and 121.

  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 or inert gas and a luminescent material. Mercury, iron, metal halide, etc. are used as the luminescent material. In the present embodiment, iron (Fe) and thallium (Tl) halides are used as the luminescent material in order to improve spectral characteristics. It is known that starting time can be shortened by enclosing two types of halides rather than one type of halide. This is because the sum of the vapor pressures of both halides contributes to shortening the starting time. Therefore, in this embodiment, iron bromide (FeBr ₂ ) and iron iodide (FeI ₂ ) are encapsulated as the luminescent material, and further thallium iodide (TlI) is encapsulated. Here, mercury, iron bromide, iron iodide, and thallium iodide are selected as the luminescent material, but in this embodiment, other materials such as mercury, iron alone, and other metal halides are used as the luminescent material. May be used.

It is known that when the amount of iodine in the luminescent material becomes excessive, the plasma temperature decreases. In addition, it is known that when the amount of bromine in the luminescent material is excessive, electrons in the plasma are captured by bromine having a high electronegativity and the number of electrons contributing to light emission is reduced. Therefore, when enclosing two types of halides, it is necessary to set the ratio between the two to an appropriate value. Here, the content ratio R of iron bromide (FeBr ₂ ) is defined by the following formula (1).

Formula (1) R = M [FeBr ₂ ] / (M [FeBr ₂ ] + M [FeI ₂ ])
Here, M [FeBr ₂ ] is the molar concentration of iron bromide (FeBr ₂ ) (unit: mol / cc), and M [FeI ₂ ] is the molar concentration of iron iodide (FeI ₂ ) (unit: mol / cc). It is.

According to this embodiment, the content ratio R of iron bromide of formula (1) was 0.38, and the amount of thallium iodide (TlI) sealed was 1.2 × 10 ⁻⁷ mol / cc.

  Next, an example of the electrodeless lamp used in the experiment conducted by the inventor will be described in detail. In an experiment conducted by the present inventor, an electrodeless lamp shown in FIG. 4 was used. In the electrodeless lamp used in the experiment conducted by the inventors of the present application, L1 = L + 2Lt = 155 mm, L = 138 mm, and Lt = 8.5 mm. La = 20 mm, Lb = 19.5 mm, and Lc = 39.5 mm. Dc = 11 mm, Da = 5 mm, Dt = 3 mm. The thickness of the discharge vessel 12A was 1 mm. The internal volume of the discharge vessel 12A was 6.3 cc.

  The discharge vessel was filled with argon gas of 15 ± 5 Torr as a starting rare gas or inert gas.

The content ratio R of iron bromide of the formula (1) was 0.38. The amount of thallium iodide (TlI) enclosed was 1.2 × 10 ⁻⁷ mol / cc.

  The results of experiments conducted by the present inventor will be described with reference to FIGS. 5A and 5B. The inventor of the present application measured the relationship between the amount of enclosed mercury and the emission intensity using the electrodeless lamp according to this embodiment shown in FIG. In addition, a spectrum of emission intensity was measured.

FIG. 5A shows the result of measuring the relationship between the amount of mercury enclosed and the emission intensity at a wavelength of 315 to 400 nm (UV-A region). The horizontal axis represents the amount of mercury enclosed (unit: × 10 ⁻⁵ mol / cc), and the vertical axis represents the emission intensity (unit: mW / cm ² ) at a wavelength of 315 to 400 nm (UV-A region). From the graph of FIG. 5A, the emission intensity becomes maximum (356 mW / cm ² ) when the mercury filling amount is 0.7 × 10 ⁻⁵ mol / cc. The emission intensity decreases even if the mercury content is increased or decreased from 0.7 × 10 ⁻⁵ mol / cc. Here, an electrodeless lamp having an emission intensity (UV-A range) of 250 mW / cm ² or more is regarded as acceptable. From the graph of FIG. 5A, the emission intensity is 250 mW / cm ² or more when the mercury encapsulation amount is in the range of 0.3 × 10 ^{−5 to} 3.0 × 10 ⁻⁵ mol / cc.

In experiments conducted by the present inventor, it has been found that discharge becomes unstable as the amount of mercury enclosed increases. Thus, it has been found that the mercury filling amount should be 1.4 × 10 ⁻⁵ mol / cc or less in order to ensure the discharge stability. This will be described in detail later with reference to FIGS. 6A and 6B. From the above, in order to set the emission intensity to 250 mW / cm ² or more and ensure the discharge stability, the mercury filling amount should be in the range of 0.3 × 10 ^{−5 to} 1.4 × 10 ⁻⁵ mol / cc. That's fine.

  In the experiment conducted by the present inventor, the emission intensity in the UV-A region changes when the amount of mercury enclosed changes, but the spectral spectrum also changes. Therefore, the inventor of the present application measured the spectrum.

FIG. 5B shows the result of measuring the spectral spectrum when the amount of mercury enclosed is 0.3 × 10 ⁻⁵ mol / cc, 0.7 × 10 ⁻⁵ mol / cc and 1.4 × 10 ⁻⁵ mol / cc. Indicates. The horizontal axis represents wavelength (unit: nm), and the vertical axis represents spectral radiation intensity (unit: mW / cm ² / nm).

  It is known that mercury emission appears at a wavelength of 365 nm, iron emission appears at a wavelength of 358 nm, 373 nm, 382 nm, and thallium emission appears at a wavelength of 352 nm.

First, the solid line graph is analyzed. The solid line graph shows the spectrum when the mercury content is 0.7 × 10 ⁻⁵ mol / cc. As described above, the emission intensity becomes maximum when the mercury filling amount is 0.7 × 10 ⁻⁵ mol / cc. As shown in the figure, mercury emission near a wavelength of 365 nm, iron emission such as wavelengths of 358 nm, 373 nm, and 382 nm, and thallium emission near a wavelength of 352 nm appear clearly. The magnitudes of these five emissions are approximately the same. Therefore, the electrodeless lamp of the present embodiment is suitable for applications that selectively or simultaneously use ultraviolet rays having wavelengths of 352 nm, 365 nm, 358 nm, 373 nm, and 382 nm. In particular, the electrodeless lamp of this embodiment is suitable for use as an ultraviolet light source for resin curing. Furthermore, in this embodiment, the amount of mercury used is relatively small. Therefore, this embodiment is suitable when it is necessary to reduce the amount of mercury used.

Next, the broken line graph is analyzed. The broken line graph shows a spectral spectrum when the mercury content is 0.3 × 10 ⁻⁵ mol / cc. In this way, when the amount of mercury enclosed is relatively small, light emission of mercury near the wavelength of 365 nm does not appear. Instead, thallium emission near a wavelength of 352 nm and iron emission such as wavelengths of 358 nm, 373 nm, and 382 nm appear relatively clearly. Therefore, the electrodeless lamp of the present embodiment is unsuitable for applications using ultraviolet light having a wavelength of around 365 nm, but is suitable for applications using ultraviolet light having wavelengths of 352 nm, 365 nm, 358 nm, 373 nm, and 382 nm selectively or simultaneously. It is. Furthermore, this embodiment is suitable when it is necessary to reduce the amount of mercury used.

Analyze the dotted line graph. The dotted line graph shows the spectrum when the mercury content is 4.2 × 10 ⁻⁵ mol / cc. As described above, this example is not preferable because the discharge becomes unstable. Thus, when the amount of mercury enclosed is relatively large, light emission of mercury near a wavelength of 365 nm appears remarkably. Instead, thallium emission near a wavelength of 352 nm and iron emission such as wavelengths 358 nm, 373 nm, and 382 nm do not appear clearly.

This will be described with reference to FIGS. 6A and 6B. As described above, from experiments conducted by the inventors of the present application, it has been found that discharge becomes unstable when the amount of mercury enclosed increases. The reason is that as the amount of mercury enclosed increases, the mercury vapor pressure easily reaches the saturated vapor pressure, and mercury condenses on the tube wall of the discharge vessel. Therefore, the upper limit of the amount of mercury enclosed to ensure discharge stability was examined. As a result, it was found that the amount of mercury enclosed should be 1.4 × 10 ⁻⁵ mol / cc or less.

FIG. 6A shows a state in which the discharge is stable when the amount of mercury enclosed is 1.4 × 10 ⁻⁵ mol / cc or less. On the other hand, FIG. 6B shows a state in which the discharge is unstable due to an excessive amount of mercury enclosed.

As a comparative example, the inventor of the present application prototyped a straight tube-type electrodeless discharge lamp disclosed in Patent Document 3, and measured the ultraviolet intensity with a constant input power of 1.6 kW. The discharge tube was filled with 1.6 × 10 ⁻⁶ mol / cc of mercury iodide, 0.13 mg / cc of iron, and 2.6 × 10 ⁻⁵ mol / cc of mercury as a luminescent substance. Further, argon gas of 50 Torr was sealed in the discharge tube. In this comparative example, the maximum value of the ultraviolet intensity in the UV-A region was 221 mW / cm ² . On the other hand, the maximum value of the emission intensity in this embodiment shown in FIG. 5A was 356 mW / cm ² . Therefore, with respect to the maximum value of the UV intensity in the UV-A region, the comparative example is lower than the present embodiment, and further, the emission intensity 250 mW / cm ² set by the present inventor has not been reached. From the above, it can be said that the electrodeless lamp according to the present embodiment can obtain a higher ultraviolet intensity than the conventional technique.

  The findings obtained from experiments conducted by the inventors of the present application will be summarized.

(1) In order to set the emission intensity to 250 mW / cm ² or more and to ensure discharge stability, the mercury enclosed amount in the discharge vessel is 0.3 × 10 ^{−5 to} 1.4 × 10 ⁻⁵ mol / cc. A range may be used.

  (2) Although a normal straight tube type may be used as the discharge vessel, it is preferable to use a discharge vessel having a shape having a reduced diameter central portion in a central low temperature region (cold zone).

  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, 122 ... center of reduced diameter, 123 ... end portion, 124 ... tapered portion, 131 ... belly, 132 ... node

Claims (3)

In microwave electrodeless lamps that emit light upon receiving microwave energy,
A tubular discharge vessel made of quartz glass;
A rare gas and a luminescent material enclosed in the discharge vessel,
The light-emitting substance contains 0.3 × 10 ⁻⁵ mol / cc to 1.4 × 10 ⁻⁵ mol / cc of mercury, and further contains iron iodide, iron bromide, and thallium iodide. Wave electrodeless lamp. The microwave electrodeless lamp according to claim 1, wherein
The discharge vessel has a reduced diameter central portion, a tapered portion connected to both sides of the reduced diameter central portion, and a cylindrical portion connected to each outer end of the tapered portion, and the reduced diameter central portion The outer diameter of the cylindrical portion is smaller than the outer diameter of the cylindrical portion, and the central portion of the reduced diameter is formed at a position corresponding to a low temperature region formed corresponding to a standing wave node of a plasma region generated by microwave energy. Microwave electrodeless lamp characterized by being made. 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 filled with an inert gas and a luminescent material,
The light emitting material contains 0.7 × 10 ⁻⁵ mol / cc to 1.4 × 10 ⁻⁵ mol / cc of mercury, and further contains iron iodide, iron bromide, and thallium iodide. Irradiation device.