JP2010238573A - Fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluorescent lamp for improving the transmittance of fluorescent light emitted from a phosphor while maintaining high transmittance of fluorescent light over a long period from starting the use of the lamp by suppressing reaction between mercury existing in the internal space of a glass tube and alkali metal in the glass tube when using the lamp. <P>SOLUTION: The fluorescent lamp includes the glass tube filled with gas containing mercury for producing ultraviolet rays with discharge, a phosphor layer provided on the inner face of the glass tube, and a protecting layer provided on the surface of the phosphor layer or between the phosphor layer and the glass tube. The protecting layer contains semiconductor fine particles that coats of silicon oxide are formed on the surfaces of semiconductor nano particles, or semiconductor fine particles that hydrocarbon groups are joined to the surfaces of the semiconductor nano particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fluorescent lamp and a method for manufacturing the same, and more particularly to a fluorescent lamp capable of suppressing a decrease in luminance due to use and extending its life.

  When a voltage is applied between the electrodes, the fluorescent lamp ionizes the noble gas present in the glass tube, collides the ionized noble gas with the electrode, emits secondary electrons, and generates a glow discharge, thereby generating mercury. When excited, 253.7 nm ultraviolet rays are emitted, and fluorescence is emitted from the phosphor contained in the phosphor layer provided on the inner wall surface of the glass tube.

  In this type of fluorescent lamp, the alkali metal contained in the glass tube reacts with mercury as it is used. As a result, the black reactant interferes with the fluorescence transmitted through the glass tube, reducing the brightness of the lamp and reducing the mercury. As a result, the lamp life is shortened. For this reason, a protective layer is provided on the surface of the phosphor layer or between the phosphor layer and the glass tube to suppress contact between mercury present in the interior space of the glass tube and alkali metal deposited on the surface from within the glass tube. is doing.

  Such a protective layer is preferably formed of a material that not only protects the glass tube from deterioration due to ultraviolet rays emitted from mercury but also suppresses its own deterioration, and uses a metal oxide such as yttrium oxide. Has been. However, the protective layer formed of a metal oxide or the like may absorb some of the fluorescence emitted from the phosphor, and is less susceptible to degradation by ultraviolet light. A metal oxide such as yttrium oxide reduces the fluorescence transmittance. Tend to. For this reason, although the effect which suppresses the fall of the brightness | luminance accompanying use of a fluorescent lamp is high, the brightness immediately after use starts falls from the thing which does not have a protective layer. In addition, since ultraviolet rays other than those that excite phosphors are present, there is waste in terms of the use of ultraviolet rays.

  A low refractive agent (Patent Documents 1 to 3) containing silica fine particles or the like is applied on the inner wall surface of the glass tube to suppress reflection on the glass tube surface. However, even if these protective layers are provided, it is difficult to sufficiently block the reaction between mercury and alkali metal, and there is a protective layer that can suppress a decrease in luminance accompanying use and can prolong the life. It has been requested.

JP 2006-342023 JP 2006-335881 JP 2004-083307 A

  The problem of the present invention is that the transmittance of the fluorescence emitted from the phosphor is high, and ultraviolet rays other than the ultraviolet light of 253.7 nm that excites the phosphor are used for light emission. Providing a fluorescent lamp that suppresses the reaction between mercury in the space and the alkali metal in the glass tube, and maintains a high fluorescence transmittance from the start of lamp use over a long period of time. There is to do.

  The present invention relates to a glass tube enclosing a gas containing mercury that generates ultraviolet rays by discharge, a phosphor layer provided on the inner surface of the glass tube, and a surface of the phosphor layer or a phosphor layer and a glass tube. In a fluorescent lamp having a protective layer therebetween, the protective layer includes semiconductor fine particles in which a silicon oxide coating is formed on the surface of the semiconductor nanoparticles, or semiconductor fine particles in which hydrocarbon groups are bonded to the surface of the semiconductor nanoparticles. The present invention relates to a fluorescent lamp.

  The fluorescent lamp of the present invention has a high transmittance of the fluorescence emitted from the phosphor, and suppresses the reaction between mercury present in the interior space of the glass tube and the alkali metal in the glass tube with the use of the lamp. In addition, it is possible to maintain a high fluorescence transmittance over a long period of time from the start of use of the lamp.

It is the schematic block diagram (a) and partial sectional view (b) which show an example hot electrode fluorescent lamp to which the fluorescent lamp of this invention is applied. It is a figure which shows the schematic sectional drawing which shows the cold cathode fluorescent lamp of the other example to which the fluorescent lamp of this invention is applied. It is a figure which shows the side view (a) and schematic sectional drawing (b) of the external electrode type | mold fluorescent lamp of the other example to which the fluorescent lamp of this invention is applied.

  The fluorescent lamp of the present invention includes a glass tube in which a gas containing mercury that generates ultraviolet rays by discharge is sealed, a phosphor layer provided on the inner surface of the glass tube, the surface of the phosphor layer or the phosphor layer and glass. In a fluorescent lamp having a protective layer between a tube and a protective layer, the protective layer includes semiconductor fine particles in which semiconductor nanoparticles are oxidized to form an oxide coating on the surface.

  The glass tube used for the fluorescent lamp of the present invention may be any material as long as it is made of a material that transmits visible light. Examples of the material of the glass tube include soda glass, borosilicate glass, lead glass, aluminosilicate glass, borate glass, and phosphate glass. The shape may be any of a straight pipe type, a curved type, an annular type, a valve type, and the like.

  In the internal space of the glass tube, mercury that generates ultraviolet rays is enclosed together with a rare gas such as argon or neon, and the discharge electrons generated in the glass tube collide with mercury atoms to generate ultraviolet rays including 253.7 nm. . Examples of the amount of mercury to be enclosed include an amount in which the vapor pressure when the fluorescent lamp is turned on is, for example, 1 to 10 Pa.

  Inside the both ends of the glass tube, a pair of electrodes is provided as means for generating a discharge for emitting ultraviolet rays from the mercury atoms. Such an electrode may be a hot electrode, a cold cathode, an external electrode, or the like. Examples of the hot electrode include a hot electrode made of a tungsten coil coated with an emitter material such as an oxide such as barium, calcium, and yttrium. When a voltage is applied between the electrodes, the hot electrode is emitted from the emitter. The rare gas is ionized by the generated electrons, and ions of the rare gas collide with the electrode to cause a glow discharge, thereby exciting mercury and emitting ultraviolet rays. As the cold cathode, for example, a cup-shaped electrode formed of nickel, molybdenum or the like is disposed with the openings facing each other, and when a voltage is applied between them, a rare gas is generated by electrons slightly present in the glass tube. Is ionized, and when it collides with the electrode, a discharge is generated and ultraviolet rays are emitted from mercury. As an external electrode, for example, an aluminum foil or the like is bonded to the outer wall surfaces of both ends of the glass tube with a conductive adhesive, a voltage is applied to the external electrode via a lead wire, and a discharge is similarly generated in the internal space of the glass tube. Generate.

The phosphor layer provided on the inner wall of such a glass tube contains a phosphor that emits visible light by ultraviolet rays of 253.7 nm emitted from mercury atoms. As a phosphor, there is a case where the deterioration of heat is low, mercury adsorption is small, and the mercury vapor pressure continues to be high at the start of the fluorescent lamp. What can suppress deterioration of the light-transmitting tube due to mercury adsorbed on the surface is preferable. Examples of such phosphors include Y ₂ O ₃ : Eu, YVO ₄ : Eu, LaPO ₄ : Ce, Tb, (Ba, Eu) MgAl ₁₀ O ₁₇ , (Ba, Sr, Eu) (Mg, Mn). Al ₁₀ O ₁₇ , Sr ₁₀ (PO ₄ ) _{6 Cl 2} : Eu, (Sr, Ca, Ba, Mg) ₁₀ (PO ₄ ) _{6 Cl 2} : Eu, and the like can be mentioned. In addition, the phosphor layer is appropriately combined with such phosphors, and excited by 253.7 nm ultraviolet rays emitted from mercury, emits visible light in the green, red, and blue regions, and emits white light with excellent color rendering. It is also possible to obtain.

  The fluorescent lamp of the present invention has a protective layer on the surface of the phosphor layer or between the phosphor layer and the glass tube. The protective layer includes semiconductor fine particles in which a silicon oxide coating is formed on the surface of the semiconductor nanoparticles, or semiconductor fine particles in which a hydrocarbon group is bonded to the surface of the semiconductor nanoparticles. Examples of the semiconductor nanoparticles used for forming such semiconductor fine particles include nanoparticles of 1 nm to 5 nm, such as silicon and zinc telluride. Since the semiconductor nanoparticles having such a particle size are excited by ultraviolet rays and emit fluorescence, the luminance of the lamp can be increased.

The particle diameter of the semiconductor nanoparticles can be measured by a laser analysis type particle size distribution measuring apparatus. Hereinafter, the measured value measured by the same measuring device can be adopted for the particle diameter. The semiconductor nanoparticles have a silicon oxide coating on the surface. By having the coating of silicon oxide, it is possible to suppress oxidation of the semiconductor nanoparticles, and it is possible to suppress reduction of fluorescence emission due to fluctuations in the particle diameter of the semiconductor nanoparticles. The thickness of the coating is preferably 1 nm or more and 0.995 μm or less. If the thickness of the silicon oxide coating is 1 nm or more, the semiconductor nanoparticles can be prevented from being oxidized, and the reaction between alkali metal and mercury contained in the glass tube can be suppressed. For example, inhibition of fluorescence transmission from the semiconductor nanoparticles can be suppressed.

  As the thickness of the coating, a value calculated by measuring semiconductor fine particles using a laser analysis type particle size distribution analyzer, a fluorescent X-ray analyzer, an SEM apparatus, or the like can be adopted.

  As a method of forming a silicon oxide coating on such semiconductor nanoparticles, it is preferable to use a reverse micelle method. As the reverse micelle method, a water-soluble solvent such as water or alcohol in a hydrophobic solvent, a surfactant, a silane compound having an organic group such as tetramethoxysilane, and water-soluble semiconductor nanoparticles, hydrochloric acid, nitric acid, ammonia, etc. The silica coating formed by the sol-gel reaction of the silane compound on the semiconductor nanoparticles moved into the water-soluble solvent dispersed in the hydrophobic solvent with a particle size of about 5 nm to 100 nm by adding together with the catalyst of The method of forming can be mentioned. Dispersing the water-soluble solvent with a particle size of about 5 nm to 100 nm by setting the molar ratio of the silane compound to the water-soluble solvent to 0.25 to 4 and the molar ratio of the surfactant to the water-soluble solvent to 6 to 18. The resulting semiconductor fine particles can be formed to have a desired particle size. Thereafter, the solvent can be removed to obtain semiconductor fine particles.

In addition, the semiconductor nanoparticles have a hydrocarbon group on the surface. By having the hydrocarbon group, the semiconductor nanoparticles can be prevented from being oxidized, and the fluorescence emission can be prevented from being reduced due to fluctuations in the particle diameter of the semiconductor nanoparticles. The hydrocarbon group may be any of linear, branched or cyclic, such as an alkyl group, alkenyl group, alkynyl group, cycloalkyl group, aryl group, etc. Therefore, it is preferable. For example, as a method of bonding hydrocarbon groups to the surface of silicon nanoparticles, an alloy powder represented by Mg ₂ Si and excess silicon tetrachloride were reacted in a solvent such as tetrahydrofuran under an inert gas atmosphere. Thereafter, by removing the solvent and excess silicon tetrachloride, silicon nanoparticles having chlorine atoms bonded around a substantially spherical cluster having silicon atoms bonded three-dimensionally are obtained. By reacting the obtained silicon nanoparticle with an alkylating agent represented by RMgX or RLi (R represents an alkyl group, X represents a halogen atom) in a solvent, the halogen atom of the silicon nanoparticle is converted to an alkyl group. Semiconductor fine particles substituted with can be obtained.

  The average particle diameter of the semiconductor fine particles having a coating or hydrocarbon group on the surface of such semiconductor nanoparticles is preferably 2 nm or more and 1.0 μm or less. If the average particle size of the semiconductor fine particles is 1.0 μm or less, a high-density protective layer can be formed, thereby enhancing the shielding effect between alkali metal contained in the glass tube and mercury existing in the internal space. It is possible to suppress contact with each other, and to suppress a reduction in lamp brightness and a short life.

  The protective layer containing the semiconductor ultrafine particles may contain other metal oxide fine particles and a binder that binds these as long as the function of the semiconductor fine particles is not impaired. Examples of the metal oxide fine particles include aluminum oxide, titanium oxide, zinc oxide, silicon oxide, yttrium oxide, lanthanum oxide, and magnesium oxide. The metal oxide preferably has an average particle size of 5 nm or more and 1.0 μm or less because a high-density protective layer can be formed and contact between mercury and an alkali metal can be suppressed. In addition, when the particle diameter of the metal oxide is 1.0 μm or less, it is excited by ultraviolet rays and emits fluorescence, so that the luminance of the lamp can be improved. Examples of the binder include polyethylene oxide (PEO) and hydroxyethyl cellulose (HEC).

  The content of the semiconductor fine particles in the protective layer largely depends on the particle size. For example, when the average particle size of the semiconductor fine particles is 30 nm, the content of the metal oxide fine particles is 0 to 90% by mass. Preferably there is.

  The thickness of the protective layer is preferably in the range of 0.5 μm to 5.0 μm. If the thickness of the protective layer is 0.5 μm or more, the reaction between mercury and alkali metal can be suppressed to a high degree, and if it is 5.0 μm or less, the decrease in fluorescence transmittance is suppressed. Can do.

  In order to prepare the protective layer, for example, a method of preparing a dispersion in which semiconductor fine particles, if necessary, metal oxide fine particles, and a binder are dispersed in an organic or aqueous dispersion medium, and applying and drying the dispersion is prepared. Can be used. Specific examples of the dispersion medium include water, organic solvents such as alcohols, butyl acetate, and xylene, and mixtures thereof. The application method may be any of coating, dipping, spray application and the like. After applying to a predetermined thickness, it can be dried by a drying method such as natural drying or forced drying. In the case of forced drying, when the speed or temperature of air blow or the like is high, the drying of only the surface precedes, the internal drying speed is slow, and stress is generated inside and outside, which causes cracking. For this reason, for example, it is preferable to adjust the temperature and the air blow speed. The dispersion may be applied a plurality of times to obtain a protective layer having a desired thickness.

  The fluorescent lamp of the present invention is suitable for any fluorescent lamp such as a hot electrode fluorescent lamp, a cold cathode fluorescent lamp, and an external electrode fluorescent lamp. As a lighting circuit for driving this type of fluorescent lamp, a starter type lighting circuit that preheats an electrode and generates a high-pressure pulse by a lighting circuit provided separately from the fluorescent lamp can be used, but is provided integrally with the fluorescent lamp. Further, a rapid start type lighting circuit including a ballast having an electrode preheating circuit and a booster circuit, and an inverter type lighting circuit including a high frequency conversion circuit can also be used. When the lighting circuit is provided in an integrated manner, the glass tube is bent or bent, and its periphery is further covered with a globe, and the bulb has a base connected to the lighting circuit, or the glass tube is exposed to the outside. Also good.

A method for manufacturing such a fluorescent lamp is not particularly limited, and for example, the following method can be used. Dispersed water containing semiconductor fine particles and metal oxide fine particles is applied to the inner wall surface of the glass tube by sucking it into the glass tube, dried at 60 to 80 ° C. for 1 to 5 minutes, and having a thickness of 0.5 to 5 A coating layer of 0.0 μm is formed to form a protective layer. In addition, for example, dispersion water containing phosphor such as Y ₂ O ₃ : Eu is added so that phosphoric acid is 0.1% by mass with respect to the phosphor, and the dispersion water whose viscosity is adjusted, It is applied by sucking into a glass tube and dried at 60 to 80 ° C. for 1 to 10 minutes to form a coating film having a thickness of 20 to 30 μm to form a phosphor layer. Alternatively, a phosphor layer is formed on the inner wall surface of the glass tube, and a protective layer is formed thereon. Thereafter, an electrode is provided at the end of the glass tube and sealed with a base having an external lead connected to the electrode, and a predetermined amount of rare gas and mercury are introduced into the internal space of the glass tube to obtain a fluorescent lamp. .

  The fluorescent lamp of the present invention inhibits contact between mercury and an alkali metal contained in a glass tube when the phosphor is excited by 253.7 nm ultraviolet rays emitted from mercury atoms to emit visible light. Can suppress the formation of a product. In addition, since the protective layer has a high fluorescence transmittance, it is possible to suppress a decrease in luminance even after a long time of use since the disclosure of the use of the lamp, and the semiconductor fine particles contained in the protective layer themselves emit fluorescence. Therefore, the brightness can be maintained at a higher level.

  An example in which the fluorescent lamp of the present invention is applied to a hot electrode fluorescent lamp is shown in FIG. 1A is a schematic configuration diagram, and FIG. 1B is a partial cross-sectional view of B shown in FIG. A hot electrode fluorescent lamp 10 shown in FIG. 1 has a glass tube 1 formed of soda glass. As the glass tube 1, for example, one having an outer diameter of 15.5 to 38 mm can be used. On the inner wall surface of the glass tube 1, the protective layer 2 is provided over almost the entire length, and the phosphor layer 3 is laminated on the protective layer 2. Both ends of the glass tube 1 are closed by a stem 5 provided with an electrode 6, a predetermined amount of rare gas and mercury are introduced into the internal space of the glass tube, and the internal pressure is about several tenths of atmospheric pressure. Has been depressurized. Further, a base 7 connected to the stem 5 is provided outside the both ends of the glass tube 1.

  An example in which the fluorescent lamp of the present invention is applied to a cold fluorescent lamp is shown in FIG. In the cold cathode fluorescent lamp 21 shown in the schematic cross-sectional view of FIG. 2, both ends of a glass tube 22 formed of soda glass are hermetically sealed with bead glass 23. As the glass tube 22, for example, one having an outer diameter of 1.5 to 6.0 mm, preferably 1.5 to 5.0 mm can be used. The inner wall surface of the glass tube 22 has the protective layer 24a over almost the entire length, and the phosphor layer 24b is laminated on the protective layer. A predetermined amount of rare gas and mercury are introduced into the internal space 25 of the glass tube 22, and the internal pressure is reduced to several tenths of the atmospheric pressure. In the vicinity of both ends of the glass tube 22, for example, cup-shaped electrodes 27 having an outer diameter of 0.7 to 3.5 mm and a thickness of 0.05 to 1.0 mm are arranged so that the openings 20 face each other. Has been placed. Each lead wire 29 is provided with one end welded to the bottom surface of the electrode 27 and the other end penetrating the bead glass 23 and drawn out of the glass tube 22.

  An example in which the fluorescent lamp of the present invention is applied to an external electrode fluorescent lamp is shown in FIG. The external electrode fluorescent lamp 31 shown in the side view of FIG. 3A and the schematic cross-sectional view of FIG. 3B has a glass tube 32 made of soda glass sealed at both ends. The outer diameter of the glass tube 32 can be in the range of 1.5 to 6.0 mm, preferably in the range of 1.5 to 5.0 mm. The inner wall surface of the glass tube 32 has the protective layer 33a over almost the entire length, and the phosphor layer 33b is laminated on the protective layer. A predetermined amount of rare gas and mercury are introduced into the internal space of the glass tube 32, and the internal pressure is reduced to about several tenths of the atmospheric pressure. External electrodes 34 are provided on the outer peripheral surfaces of both end portions of the glass tube 32. The external electrode 34 can be provided by adhering a metal foil such as aluminum or nickel to the outer surface of the glass tube 32 with a conductive adhesive or the like in which a metal powder is mixed with silicon resin, and covers the entire end of the glass tube 32. It can also be provided. Examples of the length L1 in the longitudinal direction of the external electrode include 10 to 35 mm. A lead wire (not shown) is connected to the external electrode, and voltage can be applied to the electrode via the lead wire.

The present invention will be described in more detail with reference to the following examples, but the technical scope of the present invention is not limited thereto.
[Example 1]
Viscosity is adjusted by adding 7.77 g of silicon particles having an average particle diameter of 2 to 4 nm having a silicon oxide coating and 7.77 g of silica powder (metal oxide fine particles) having an average particle diameter of 30 nm as metal oxide particles to 300 ml of water. To prepare a dispersion. This was sucked into a soda glass tube having a tube diameter of 28.0 mm and dried at 60 ° C. to form a protective layer having a thickness of 1 μm. A coating solution using a three-wavelength phosphor was prepared, a phosphor layer having a thickness of 20 μm was formed on the protective layer, and a fluorescent lamp shown in FIG. 1 was produced.

A voltage was applied to the obtained fluorescent lamp, and after 100 hours, the total luminous flux value was measured using an integrating sphere. Compared with the comparative example, the total luminous flux value was improved by 1.3%.
[Example 2]
A fluorescent lamp was prepared in the same manner as in Example 1 except that silicon particles having an average particle diameter of 2 to 4 nm bonded with hydrocarbon groups were used instead of silicon particles having a silicon oxide coating, and the total luminous flux value was measured. did. Compared with the comparative example, the total luminous flux value was improved by about 0.5%.
[Comparative example]
A protective layer was prepared in the same manner as in Example 1 except that only alumina fine particles having an average particle diameter of 50 nm were used, a fluorescent lamp was produced, and the total luminous flux value was measured.

1, 22, 32 Glass tube 2, 24a, 33a Protective layer 3, 24b, 33b Phosphor layer 6 Electrode 10 Hot electrode fluorescent lamp 21 Cold cathode fluorescent lamp 27 Cup-shaped electrode (electrode)
31 External electrode fluorescent lamp 34 External electrode (electrode)

Claims (6)

  A glass tube enclosing a gas containing mercury that generates ultraviolet rays by discharge, a phosphor layer provided on the inner surface of the glass tube, and a protective layer between the surface of the phosphor layer or between the phosphor layer and the glass tube The protective layer includes semiconductor fine particles in which a silicon oxide coating is formed on the surface of the semiconductor nanoparticles, or semiconductor fine particles in which hydrocarbon groups are bonded to the surface of the semiconductor nanoparticles. Fluorescent lamp.   The fluorescent lamp according to claim 1, wherein the semiconductor nanoparticles are silicon nanoparticles.   3. The fluorescent lamp according to claim 1, wherein the average particle diameter of the semiconductor fine particles is in the range of 2 nm to 1.0 μm.   The fluorescent lamp according to any one of claims 1 to 3, wherein the coating of the semiconductor fine particles on the silicon oxide has a thickness in the range of 1 nm to 0.995 µm.   The fluorescent lamp according to any one of claims 1 to 4, wherein the thickness of the protective layer is in the range of 0.5 µm to 5.0 µm.   The fluorescent lamp according to any one of claims 1 to 5, wherein the protective layer contains metal oxide fine particles having an average particle diameter of 5 nm to 1.0 µm.

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