KR20120075358A - Light irradiation unit - Google Patents

Abstract

PURPOSE: A light radiating unit is provided to radiate light of a wavelength band related to an ultraviolet lamp which a user wants to turn on. CONSTITUTION: A light radiating unit(20) includes an ultraviolet lamp(10A), a fluorescent lamp(10B-10D) and a cooling device for preventing the overheat of the ultraviolet lamp and the fluorescent lamp. The lighting order of the ultraviolet lamp and the fluorescent lamp is properly set according to a purpose. The light emitting wavelength of the ultraviolet is different from the light emitting wavelength of the fluorescent lamp. A reflection mirror(21) radiates light from the fluorescent lamp to an opening surface of a housing(25).

Description

Light irradiation unit {LIGHT IRRADIATION UNIT}

The present invention relates to a light irradiation unit in which ultraviolet lamps and fluorescent lamps having different wavelength bands of emitted ultraviolet light are provided side by side.

Conventionally, a light irradiation unit in which a plurality of rare gas fluorescent lamps are provided side by side is known (see Patent Document 1, for example). Also, a plurality of rare gas fluorescent lamps in such a light irradiation unit have different emission wavelength bands. It is developed as an apparatus related to plant growth. The light irradiation unit related to the growth of this plant can emit light of a desired emission wavelength band by selecting a rare gas fluorescent lamp to be lit.

However, in such a light irradiation unit in which a plurality of rare gas fluorescent lamps having different emission wavelength bands are provided side by side, together with the light of the wavelength band emitted from one desired rare gas fluorescent lamp, is generated by the emitted light from the one rare gas fluorescent lamp. There was a problem that the phosphor of another rare gas fluorescent lamp was unintentionally excited and the light of the wavelength band related thereto was also radiated.

Patent Document 1: Japanese Unexamined Patent Publication No. 2010-179240

This invention is made | formed based on the above circumstances, The objective is the fluorescent substance of the fluorescent lamp which does not want to light in the light irradiation unit in which the ultraviolet-ray lamp and fluorescent lamp in which light emission wavelength bands differ from each other are provided side by side. It is to provide a light irradiation unit capable of emitting light of a wavelength band related to an ultraviolet lamp, which is not excited and thus irradiated with light of a wavelength band related thereto.

The light irradiation unit of the present invention is a light irradiation unit arranged side by side so that the rod-shaped ultraviolet lamp and the rod-shaped fluorescent lamp extend in the same direction,

The ultraviolet lamp and the fluorescent lamp are different in emission wavelength band from each other,

The fluorescent lamp is characterized by comprising a light emitting tube made of a material that does not transmit light in a wavelength band emitted from the ultraviolet lamp.

Moreover, the light irradiation unit of this invention is a light irradiation unit arrange | positioned side by side so that a rod-shaped fluorescent lamp and a rod-shaped ultraviolet lamp may extend in the same direction,

The fluorescent lamp and the ultraviolet lamp are different from each other in the emission wavelength band,

The fluorescent lamp comprises a phosphor which does not excite in light of the wavelength band emitted from the ultraviolet lamp but excites by light in a wavelength band shorter than the short wavelength end of the light in the wavelength band emitted from the ultraviolet lamp. It is done.

Moreover, the light irradiation unit of this invention is a light irradiation unit arrange | positioned side by side so that a rod-shaped 1st fluorescent lamp, a rod-shaped 2nd fluorescent lamp, and a rod-shaped ultraviolet lamp may extend in the same direction,

The first fluorescent lamp, the second fluorescent lamp, and the ultraviolet lamp have different emission wavelength bands from each other,

The first fluorescent lamp is provided with a light emitting tube made of a material that does not transmit light in the wavelength band emitted from the ultraviolet lamp.

Phosphor excited by the second fluorescent lamp by light in the wavelength band shorter than the short wavelength end of the light in the wavelength band emitted from the first fluorescent lamp, not excited in the light of the wavelength band emitted from the first fluorescent lamp Characterized in that it comprises a.

According to the light irradiation unit of the present invention, since the fluorescent lamp is provided with a light emitting tube made of a material that does not transmit light in the wavelength band emitted from the ultraviolet lamp, it is desired to emit only light in the wavelength band related to the ultraviolet lamp. Even if the light in the wavelength band emitted from the ultraviolet lamp does not penetrate the light emitting tube of the fluorescent lamp, the fluorescent lamp does not unintentionally emit light and the light in the unwanted wavelength band associated with it is desired to be turned on. Only light in the wavelength band associated with the ultraviolet lamp can be emitted.

In addition, according to the light irradiation unit of the present invention, the fluorescent lamp does not excite in light of the wavelength band emitted from the ultraviolet lamp, but by light in the wavelength band shorter than the short wavelength end of the light in the wavelength band emitted from the ultraviolet lamp. Since it is provided with the phosphor to excite, even if it is desired to emit only light in the wavelength band related to the ultraviolet lamp, the phosphor of the fluorescent lamp is unintentionally excited by the light in the wavelength band emitted from the ultraviolet lamp, and thus is not desired. The light of the wavelength band can emit only the wavelength band related to the ultraviolet lamp to be turned on without the light of the wavelength band being emitted.

1: is explanatory drawing which showed typically an example of the structure of the light irradiation unit of this invention, (a) is a cross-sectional schematic diagram, (b) is a bottom schematic diagram.
Fig. 2 is a schematic diagram showing the relationship between the light transmission wavelength band of the light emitting tube, the light emission wavelength band of light emitted from the light emitting tube or the phosphor, and the excitation wavelength band of the phosphor in one example of the configuration of the light irradiation unit according to the first embodiment of the present invention. .
3 is an explanatory cross-sectional view showing an example of the configuration of a rare gas fluorescent lamp disposed in the light irradiation unit of the present invention.
4 is a schematic diagram showing the relationship between the light transmission wavelength band of the light emitting tube, the light emission wavelength band of light emitted from the phosphor and the excitation wavelength band of the phosphor in one example of the configuration of the light irradiation unit according to the second embodiment of the present invention.

Hereinafter, the present invention will be described in detail.

<1st embodiment>

The light irradiation unit which concerns on 1st Embodiment of this invention is arrange | positioned side by side so that a rod-shaped ultraviolet lamp and a rod-shaped fluorescent lamp may extend in the same direction, and an ultraviolet lamp and a fluorescent lamp differ in light emission wavelength band from each other, The lamp is characterized by comprising a light emitting tube made of a material that does not transmit light in the wavelength band emitted from the ultraviolet lamp.

In the present invention, the "light emission wavelength band" refers to a wavelength range having a light emission intensity having a size of 10% or more of the light emission intensity of a peak wavelength.

In the present invention, the ultraviolet lamp emits light in the ultraviolet region, and examples thereof include a rare gas fluorescent lamp, a rare gas discharge lamp and an excimer lamp of an external electrode type.

Moreover, in this invention, a fluorescent lamp has fluorescent substance among ultraviolet lamps, For example, the rare-electrode fluorescent lamp of an external electrode type, etc. are mentioned.

In the rare gas fluorescent lamp, as described in detail below, a film is formed on the inner surface of the light emitting tube by a phosphor that converts light of a predetermined excitation wavelength band into light of a predetermined light emission wavelength band, and a rare gas is formed in the light emitting tube. It is a lamp which is enclosed and uses the light emission by exciting a fluorescent substance with the ultraviolet-ray by discharge in a rare gas.

In addition, the rare gas discharge lamp is a lamp in which a rare gas is enclosed in a light emitting tube without having a phosphor, and light emission by discharge in the rare gas is used.

The excimer lamp is a lamp in which a discharge gas for generating excimer molecules is enclosed in a light emitting tube by a dielectric barrier discharge. The excimer lamp forms excimer molecules by excimer discharge and uses light emitted from the excimer molecule.

1: is explanatory drawing which showed typically an example of the structure of the light irradiation unit of this invention, (a) is a cross-sectional schematic diagram, (b) is a bottom schematic diagram.

This light irradiation unit 20 is one rod-shaped in the box-shaped housing 25 which consists of metal materials, such as aluminum and stainless steel, whose one surface was opened toward one side (downward in FIG. 1 (a)). The upper ultraviolet lamp 10A and the three rod-shaped fluorescent lamps 10B to 10D are arranged side by side in a state parallel to the opening surface in the housing 25 and extending in the same direction.

The ceiling surface that faces the opening surface of the housing 25 reflects the radiation from the ultraviolet lamps 10A and the fluorescent lamps 10B to 10D to reflect toward the opening surface of the housing 25. It is.

The ultraviolet lamp 10A and fluorescent lamp 10B-10D in this light irradiation unit 20 are electrically connected to the lighting device which is not shown in figure, respectively. Thereby, the ultraviolet lamp 10A and the fluorescent lamps 10B-10D are in the state which can respectively light up.

In this light irradiation unit 20, the cooling mechanism for suppressing overheating of the ultraviolet lamp 10A and fluorescent lamps 10B-10D may be provided. Specifically, the structure etc. which send a cooling wind to the peripheral region of the ultraviolet lamp 10A and fluorescent lamps 10B-10D can be used.

In the light irradiation unit 20 of the present invention, at least two fluorescent lamps 10C disposed at a position where the fluorescent lamp 10B and the radiation light from the fluorescent lamp 10B are incident, for example, adjacent positions, The light emission wavelength bands are different from each other, and the fluorescent lamp 10C includes a light emitting tube made of a material that does not transmit light in the wavelength band emitted from the fluorescent lamp 10B.

Specifically, as shown in FIG. 2, the light emitting tube of the fluorescent lamp 10C is made of a material that transmits light in a wavelength band of 300 nm or more and shields light in a wavelength band of less than 300 mn. That is, the light of the wavelength band of 220-280 nm radiated | emitted from the fluorescent lamp 10B is shielded, and it is in the state which does not enter the fluorescent lamp 10C.

The ultraviolet lamp 10A and fluorescent lamp 10B-10D in the light irradiation unit 20 should just contain the 2 types of thing from which the light emission wavelength band differs at least, for example, the thing of the same kind for each of 2 light emission wavelength bands. It may be provided, only one may be a kind having different emission wavelength bands, or all four may be a kind having different emission wavelength bands.

In the above light irradiation unit 20, when the lamp (henceforth a "lamp for lighting") which emits light of a desired wavelength band among the ultraviolet lamp 10A and fluorescent lamps 10B-10D turns on, The light of the wavelength band radiated | emitted from the said lamp which wants to light up is reflected by the reflection mirror 21 directly or through the opening surface of the housing 25, and irradiates an irradiated object.

The lighting order of the ultraviolet lamp 10A and fluorescent lamps 10B-10D in the light irradiation unit 20 is not specifically limited, It can set suitably according to a use.

The number of simultaneous lighting of the ultraviolet lamp 10A and the fluorescent lamps 10B to 10D is not particularly limited, and may be one or all, and may be appropriately set.

[Rare gas fluorescent lamps]

As an example of the fluorescent lamp with which the above light irradiation unit 20 is equipped, the external gas type rare gas fluorescent lamp is demonstrated, for example.

As shown in FIG. 3, the rare gas fluorescent lamp includes a light emitting tube 12 made of a light-transmissive dielectric material such as glass, and the light emitting tube 12 is interposed between the light emitting tubes 12 on an outer surface of the light emitting tube 12. A pair of band-shaped external electrodes 14 and 14 spaced apart from each other are disposed along the tube axis direction of the light emitting tube 12, and light is emitted from a predetermined light emission wavelength band on the inner surface of the light emitting tube 12. The phosphor film 11 by the fluorescent substance mentioned above is formed except a part in the circumferential direction, and the aperture part 11A for light extraction is formed by the part in which the phosphor film 11 is not formed. . In the discharge space S, which is an internal space of the light emitting tube 12, a light emitting gas made of a rare gas is sealed.

In FIG. 3, 16 and 16 are protective films which cover other than the power supply part which is not shown electrically connected to the external electrodes 14 and 14, For example, it can form by baking a glass paste.

The material constituting the external electrodes 14 and 14 is not particularly limited as long as it is conductive. For example, gold, silver, nickel, carbon, gold palladium, silver palladium, platinum, aluminum, or the like can be suitably used. It can form by attaching a tape-shaped metal to the outer surface of the light emitting tube 12, or by screen-printing and baking an electrically conductive paste.

The material constituting the light emitting tube 12 is capable of transmitting light in the wavelength band emitted from the phosphor film 11, and specifically includes, for example, synthetic quartz glass, quartz glass, ozoneless quartz glass, and oxidation. Cerium-coated quartz glass, ultraviolet ray transmitting glass, soft glass, borosilicate glass, aluminosilicate glass and the like can be used.

The phosphor constituting the phosphor film 11 converts light of a predetermined excitation wavelength band into light of a predetermined emission wavelength band, and specifically, for example, LaPO ₄ : Pr, LaPO ₄ : Ce, Ce _0.8 (Mg _{0.8, Ba 0 .1) Al 11} O 18.6, YPO 4: Pr, YAl 3 B 4 0 12: Bi, SrB 4 0 7: Eu, YPO 4: Ce, YPO 4: Nd, etc. can be used.

Examples of the rare gas (encapsulated gas) enclosed in the light emitting tube 12 include Xe gas, Kr gas, Ar gas, Ne gas, or a mixed gas thereof, and the encapsulation pressure is, for example, encapsulated gas. When is Xe gas, it is preferable to set it as 50-500 Torr. When the mixed gas of Ne gas and Xe gas and the mass ratio is Ne gas: Xe gas = 7: 3, it is preferable to set it as 300-600 Torr.

In this rare gas fluorescent lamp, when a high frequency voltage is applied between the external electrodes 14 and 14, excimer discharge is generated in the discharge space S through the light emitting tube 12 made of a dielectric material, and the vacuum ultraviolet light generated by the excimer discharge is generated. As a result, the phosphors constituting the phosphor film 11 are excited to emit light to the outside of the light emitting tube 12.

According to the light irradiation unit 20 as described above, since the fluorescent lamp 10C is provided with a light emitting tube made of a material that does not transmit light in the wavelength band emitted from the fluorescent lamp 10B, the fluorescent lamp 10B Even if it is desired to emit only light in the wavelength band associated with the?), Since the light in the wavelength band emitted from the fluorescent lamp 10B does not pass through the light emitting tube of the fluorescent lamp 10C, the fluorescent lamp 10C is not intended. It is possible to emit only light in the wavelength band associated with the fluorescent lamp 10B desired to be lit, without light emission and light in the unwanted wavelength band associated therewith.

In the light irradiation unit 20 in 1st Embodiment of this invention, it is not limited to said embodiment, Various changes can be added.

For example, the fluorescent lamp 10B and the fluorescent lamp 10C are different from each other in the emission wavelength band, and the fluorescent lamp 10C is made of a material that does not transmit light in the wavelength band emitted from the fluorescent lamp 10B. Not only does the light emitting tube be provided, but also the ultraviolet lamp 10A and the fluorescent lamp 10B disposed at a position where the radiation light from the ultraviolet lamp 10A is incident, for example, in an adjacent position, have the same relationship. You can also make a configuration.

That is, the ultraviolet ray lamp 10A and the fluorescent lamp 10B have different light emission wavelength bands, and the fluorescent lamp 10B is made of a material that does not transmit light in the wavelength band emitted from the ultraviolet lamp 10A. It is possible to include a light emitting tube made of.

Specifically, as shown in FIG. 2, the light emitting tube of the fluorescent lamp 10B is made of a material that transmits light in a wavelength band of 200 mm or more and shields light in a wavelength band of less than 200 nm, that is, an ultraviolet lamp ( Light of 172 nm wavelength band radiated | emitted from 10A) may be shielded, and it may be in the state which does not enter the fluorescent lamp 10B.

<2nd embodiment>

The light irradiation unit which concerns on 2nd Embodiment of this invention has the same arrangement structure as the light irradiation unit 20 which concerns on 1st Embodiment, and a fluorescent lamp and an ultraviolet lamp differ in light emission wavelength band from each other, The fluorescent lamp is characterized by comprising a phosphor which is not excited in light of a wavelength band emitted from an ultraviolet lamp but is excited by light in a wavelength band shorter than the short wavelength end of light in the wavelength band emitted from the ultraviolet lamp. .

In the light irradiation unit of this example, at least an ultraviolet lamp and two fluorescent lamps disposed at a position where the radiation light from the ultraviolet lamp is incident, for example, adjacent positions, have different emission wavelength bands, and the fluorescent lamp is The phosphor is not excited in the light of the wavelength band emitted from the ultraviolet lamp but is provided with a phosphor that is excited by light in the wavelength band shorter than the short wavelength end of the light in the wavelength band.

Specifically, with reference to FIG. 4, the phosphor provided in the fluorescent lamp 10δ has an excitation wavelength band of 140 to 290 nm. That is, light in the wavelength band of 300 to 360 nm emitted from the ultraviolet lamp 10γ is incident on the fluorescent lamp 10δ, but the phosphor of the fluorescent lamp 10δ is not excited.

At least one of the fluorescent lamp and the ultraviolet lamp in the light irradiation unit of this example may be two kinds of light emitting wavelength bands different from each other, and for example, the same number may be provided with the same kind of light emitting wavelength bands. The kind of light emission wavelength band may differ, and all may be the kind of light emission wavelength band different from each other.

According to the light irradiation unit described above, the fluorescent lamp 10δ is shorter than the shorter wavelength end of the light in the wavelength band emitted from the ultraviolet lamp 10γ without being excited in the light in the wavelength band emitted from the ultraviolet lamp 10γ. Since the phosphor is excited by light in the phosphor wavelength band, the phosphor is excited by light in the wavelength band emitted from the ultraviolet ray lamp 10γ even if it is desired to emit only light in the wavelength band related to the ultraviolet ray lamp 10γ. It is possible to emit only light in the wavelength band associated with the ultraviolet lamp 10γ desired to be lit, without the phosphor of the lamp 10δ being unintentionally excited and irradiating light in the unwanted wavelength band associated therewith.

As mentioned above, although embodiment of the light irradiation unit of this invention was described, it is not limited to the said embodiment, A various change can be added.

Hereinafter, although the specific Example of this invention is described, this invention is not limited to these.

When the light irradiation unit shown in FIG. 2 was produced, the appropriate light irradiation unit was individually turned on one by one in order, and the spectrum of the emitted light from the light irradiation unit was irradiated. It was confirmed that only the light of the wavelength band related to the desired ultraviolet lamp which does not mix light of the band can be obtained.

<Ultraviolet lamp [10A]: excimer lamp>

? Light emitting tube: material; Synthetic quartz glass ("F310" (made by Shin-Etsu Quartz Co., Ltd.)), outer diameter; φ10 mm, full length; 450 mm, thickness; 0.5mm

? Reflection film: material; SiO ₂ -Al ₂ 0 ₃ , apertures; 60 ~ 180 °

? Insert gas: type; Xe gas, enclosed pressure; 50 ~ 500Torr

External electrode: material; Ag + frit glass, width; 4mm, full length; 410 mm

Emission wavelength band: around 146 ~ 172nm

? Method of manufacturing excimer lamp: After applying a reflecting film material made of SiO ₂ , Al ₂ O _3, etc. to the inner surface of a synthetic quartz glass tube serving as a light emitting tube, the aperture is cut and baked at about 700 to 1000 ° C. After forming and printing and firing the external electrode on the outer surface of the light emitting tube, the protective film was printed and fired, the end of the synthetic quartz glass tube was closed, heated and evacuated to about 600 ° C., and the sealing gas was introduced to seal the terminal plate completely. Was produced by soldering a lead wire to the terminal plate by soldering to an end portion of the external electrode.

<Fluorescent lamp [10B]: rare gas fluorescent lamp>

? Light emitting tube: material; Ozoneless quartz glass ("M235" (manufactured by Shin-Etsu Quartz Co., Ltd.)), outer diameter; φ10 mm, full length; 450 mm, thickness; 0.5mm

Phosphor film: phosphor material; LaPO ₄ : Pr (Pr concentration 3%), aperture; 70 ° ± 10 °

? Excitation wavelength band of phosphor: 140 ~ 200nm

? Luminous wavelength band of phosphor: 220 ~ 280nm

? Insert gas: type; Xe gas, enclosed pressure; 50 ~ 500Torr

External electrode: material; Ag + frit glass, width; 4mm, full length; 410 mm

? Method of producing a rare gas fluorescent lamp: After applying a phosphor material on the inner surface of a quartz glass tube to be a light emitting tube, the aperture is cut and fired at about 700 to 1000 ° C. to form a phosphor film, which is external to the outer surface of the light emitting tube. After printing and firing the electrode, the protective film was printed and fired, the end of the ozoneless quartz glass tube was closed, heated and evacuated to about 600 ° C., the sealing gas was introduced and completely sealed, and the terminal plate was connected to the end of the external electrode by soldering. It produced by soldering a lead wire to a terminal board.

<Fluorescent lamp [10C]: rare gas fluorescent lamps>

? Light emitting tube: material; Soft glass ("PS-94" (manufactured by Nippon Electric Glass Co., Ltd.)), outer diameter; φ10 mm, full length; 450 mm, thickness; 0.5mm

Phosphor film; Phosphor material; LaPO ₄ : Ce, aperture; 70 ° ± 10 °

The excitation wavelength band of the phosphor; 140-290 nm

The emission wavelength band of the phosphor; 300-380 nm

? Insert gas: type; Xe gas, enclosed pressure; 50 ~ 500Torr

External electrode: material; Ag + frit glass, width; 4mm, full length; 410 mm

? Method of producing a rare gas fluorescent lamp: After applying a phosphor material on the inner surface of a soft glass tube to be a light emitting tube, the aperture is cut and baked at about 500 DEG C to form a phosphor film, and an external electrode is placed on the outer surface of the light emitting tube. After printing and firing, the protective film is printed and fired, the end of the soft glass tube is closed, heated and evacuated to about 400 ° C, the encapsulation gas is introduced and completely sealed, and the terminal plate is connected to the end of the external electrode by soldering to connect to the terminal plate. It produced by soldering a lead wire.

<Fluorescent lamp [10D]: rare gas fluorescent lamps>

? Light emitting tube: material; Soft glass ("PS-94" (manufactured by Nippon Electric Glass Co., Ltd.)), outer diameter; φ10 mm, full length; 450 mm, thickness; 0.5mm

Phosphor film: phosphor material; _{Ce 0 .8 (Mg 0 .8,} Ba 0 .1) Al 11 O 18.6, aperture; 70 ° ± 10 °

? Excitation wavelength band of phosphor: 140 ~ 290nm

? Luminous wavelength band of phosphor: 310 ~ 430nm

? Insert gas: type; Xe gas, enclosed pressure; 50 ~ 500Torr

External electrode: material; Ag + frit glass, width; 4mm, full length; 410 mm

? Method of producing a rare gas fluorescent lamp: After applying a phosphor material on the inner surface of a soft glass tube to be a light emitting tube, the aperture is cut and baked at about 500 DEG C to form a phosphor film, and an external electrode is placed on the outer surface of the light emitting tube. After printing and firing, the protective film is printed and fired, the end of the soft glass tube is closed, heated and evacuated to about 400 ° C, the encapsulation gas is introduced and completely sealed, and the terminal plate is connected to the end of the external electrode by soldering to connect to the terminal plate. It produced by soldering a lead wire.

Industrial availability

The light irradiation unit of the present invention can be used as an irradiated object having a UV-curable adhesive or UV ink that reacts with light of two or more different wavelengths, and can be used as an apparatus for curing or drying them.

10A, 10γ UV Lamp 10B ~ 10D, 10δ Fluorescent Lamp
11 phosphor film 11A aperture
12 Light Emitting Tube 14 External Electrode
16 Shield 20 Light Irradiation Unit
21 Reflective Mirror 25 Housing
S discharge space

Claims (3)

In the light irradiation unit arranged side by side so that the rod-shaped ultraviolet lamp and the rod-shaped fluorescent lamp extend in the same direction,
The ultraviolet lamp and the fluorescent lamp are different in emission wavelength band from each other,
And said fluorescent lamp comprises a light emitting tube made of a material which does not transmit light in the wavelength band emitted from said ultraviolet lamp. In the light irradiation unit arranged side by side so that the rod-shaped fluorescent lamp and the rod-shaped ultraviolet lamp extend in the same direction,
The fluorescent lamp and the ultraviolet lamp are different from each other in the emission wavelength band,
The fluorescent lamp comprises a phosphor which does not excite in light of the wavelength band emitted from the ultraviolet lamp but excites by light in a wavelength band shorter than the short wavelength end of the light in the wavelength band emitted from the ultraviolet lamp. Light irradiation unit made into. In the light irradiation unit arranged side by side so that a rod-shaped 1st fluorescent lamp, a rod-shaped 2nd fluorescent lamp, and a rod-shaped ultraviolet lamp extend in the same direction,
The first fluorescent lamp, the second fluorescent lamp, and the ultraviolet lamp have different emission wavelength bands from each other,
The first fluorescent lamp is provided with a light emitting tube made of a material that does not transmit light in the wavelength band emitted from the ultraviolet lamp.
Phosphor excited by the second fluorescent lamp by light in the wavelength band shorter than the short wavelength end of the light in the wavelength band emitted from the first fluorescent lamp, not excited in the light of the wavelength band emitted from the first fluorescent lamp Light irradiation unit comprising a.

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