JPWO2009150809A1 - Glass tube for fluorescent lamp, fluorescent lamp, and lighting device - Google Patents

Abstract

A tube body made of glass containing 60 to 75 wt% silicon oxide and 5 to 18 wt% alkaline earth metal oxide, and formed on at least the outer peripheral surface of the tube body, tin oxide, titanium oxide, A first coating composed of at least one oxide selected from zirconium oxide and silicon oxide, and laminated on the first coating, and a hydrophobic lubricant or HLB was composed of 13 or less surfactant. By providing a glass tube for a lamp having a second coating, a fluorescent tube glass tube capable of reducing the bulb thickness of the fluorescent lamp is provided.

Description

  The present invention relates to a glass tube for a fluorescent lamp, a fluorescent lamp, and an illumination device.

In recent years, resource saving and CO ₂ emission reduction are required from the viewpoint of global environmental protection. As a method for saving resources and reducing CO ₂ emissions in the fluorescent lamp field, it is conceivable to reduce the thickness of a glass bulb (hereinafter simply referred to as “bulb”). That is, when the bulb is thinned, the amount of glass used as the bulb material is reduced, so that resource saving can be realized. Moreover, since the amount of combustion gas consumed in the melting furnace during glass production is reduced by reducing the amount of glass used, it is possible to reduce CO ₂ emissions.

  By the way, it is expected that the glass strength decreases when the bulb is thinned. Therefore, a device for improving the glass strength of the bulb is required. In Patent Document 1, as a method for improving the glass strength, it is disclosed to improve the scratch resistance of the glass container by forming a film made of a lubricant on the surface of the glass container and reducing the friction coefficient of the surface. Has been. Since the glass has a very high strength unless the surface is scratched, the glass strength of the glass container is improved when the scratch resistance is improved and the scratch becomes difficult to be scratched.

  Further, Patent Document 1 discloses that it is preferable to use a hydrophobic lubricant for the coating, and even if a hydrophilic lubricant is used, the scratch resistance of the glass container is not improved so much. Further, since hydrophobic lubricants have poor fixability to glass, it is also disclosed that a film made of a metal oxide is first formed on the glass surface, and a film made of a hydrophobic lubricant is formed on the film. Has been.

Japanese Patent No. 3895519

  However, when the above method was applied to produce a bulb for a fluorescent lamp, the glass strength of the bulb was formed despite the formation of a metal oxide coating and a hydrophobic lubricant coating on the bulb surface. Did not improve. Therefore, it has been difficult to reduce the thickness of the valve.

In view of the above-described problems, the present invention mainly aims to provide a fluorescent lamp glass tube capable of reducing the thickness of a fluorescent lamp bulb. Another object of the present invention is to provide a fluorescent lamp and a lighting device suitable for resource saving and CO ₂ emission reduction.

  In order to achieve the above object, a glass tube for a fluorescent lamp according to the present invention is a tube body made of glass containing 60 to 75 wt% silicon oxide and 5 to 18 wt% alkaline earth metal oxide. And a first coating formed on at least the outer peripheral surface of the tube main body and composed of at least one oxide selected from tin oxide, titanium oxide, zirconium oxide and silicon oxide, and laminated on the first coating. And a second coating film comprising a hydrophobic lubricant or a surfactant having an HLB of 13 or less.

  In addition, the content rate of the oxide described in this application is the value converted into an oxide unless there is particular description. Moreover, the numerical value range described in the present application includes a lower limit value and an upper limit value. For example, when the numerical range is 60 to 75 wt%, the numerical range includes 60 wt% and 75 wt%. Further, the glass constituting the tube main body and the oxide constituting the first coating may contain substances other than those described above to the extent of impurities.

  In the glass tube for a fluorescent lamp according to the present invention, since the glass constituting the tube main body contains an alkaline earth metal oxide of 5 wt% or more, the bulb of the fluorescent lamp can be thinned.

  Alkali metals exist as monovalent metal ions in the glass, and thus have a high mobility in the network structure of the glass. In particular, sodium has a high mobility because of its small atomic radius. As described above, the alkali metal having a high mobility is easily eluted from the glass to the glass surface as an alkali component. When the first coating is subjected to a chemical attack (chemical damage) by the alkali component thus eluted, the polarity of the coating surface increases, so that the hydrophilicity of the first coating increases, and as a result, the fixability of the second coating decreases. . As a result, the coefficient of friction on the valve surface increases, so that the scratch resistance of the valve decreases and the glass strength of the valve decreases. The inventors have described that the glass strength of the bulb is not improved even if the first coating made of metal oxide and the second coating made of a hydrophobic lubricant are formed on the surface of the bulb of the fluorescent lamp. I found it.

  In addition, it is not restricted to the heat processing by a sinter process that an alkaline component elutes from the glass of a tube main body. In the manufacturing process of a fluorescent lamp, there are other processes for heat-treating the glass tube, such as a bulb bending step for bending the bulb, a bulb sealing step for sealing the end of the glass tube, and a connection step for connecting the glass tubes together. In addition, the alkali component is easily eluted by these steps. The bent valve is a non-linear valve formed by bending a straight glass tube, such as an annular valve, a U-shaped valve, or a spiral valve.

  The glass tube for a fluorescent lamp according to the present invention suppresses the elution of the alkaline component by the alkaline earth metal. Since the alkaline earth metal exists as a divalent metal ion in the glass, the mobility in the network structure of the glass is small. Also, the ion radius is relatively large. Therefore, the movement of alkali metal in the glass is inhibited. If the alkaline earth metal is contained in an amount of 5 wt% or more, even if the glass tube is heat-treated in the manufacturing process of the fluorescent lamp, the alkali component is hardly eluted from the glass of the tube body. Therefore, the first coating is less susceptible to chemical attack, and as a result, the fixability of the second coating does not decrease, so the scratch resistance of the bulb does not decrease and the glass strength does not decrease. In addition, as for the content rate of alkaline-earth metal oxide, 5-18 wt% is more preferable, It is more preferable that it is 10-18 wt%, 12-18 wt% is the most preferable.

  1 and 2 are diagrams showing the composition and characteristics of glass constituting the tube body of the glass tube for lamp according to the embodiment. As shown in FIGS. 1 and 2, when the alkaline earth metal content of the glass constituting the tube main body was 5 wt% or more, the bulb had high scratch resistance, and the bulb had sufficient glass strength. On the other hand, when the content was less than 5 wt%, the scratch resistance of the bulb was low and the glass strength of the bulb was insufficient.

  The glass tube for a fluorescent lamp according to the present invention has good workability because the content of the alkaline earth metal oxide in the glass constituting the tube body is 18 wt% or less.

  As the content of alkaline earth metal increases, the viscosity of glass increases with temperature. That is, the glass is easy to cool and has poor processability. When the tube body is made of such glass, the workability of the glass tube is also deteriorated. In order to obtain a glass tube with good workability, it is necessary that the content of alkaline earth metal in the glass constituting the tube body be 18 wt% or less. In addition, the glass with good workability has a softening temperature in the range of 650 to 720 ° C. and a working temperature in the range of 960 to 1050 ° C. More preferably, the softening temperature is in the range of 670 to 700 ° C, and the working temperature is in the range of 960 to 1000 ° C.

  As shown in FIGS. 1 and 2, when the alkaline earth metal content was 18 wt% or less, a glass with good workability in which the softening temperature and the working temperature were within the above ranges was obtained. On the other hand, when the said content rate exceeded 18 wt%, it became glass with bad workability.

  Although the 1st film should just be comprised with the at least 1 sort (s) of oxide chosen from a tin oxide, a titanium oxide, a zirconium oxide, and a silicon oxide, it is preferable that it is comprised especially with a tin oxide. If the first coating is made of tin oxide, the glass of the tube body will not be colored or devitrified. On the other hand, when the first coating is composed of zirconium oxide, the zirconium reacts with a component in the glass to act as a crystal nucleation product, and the crystal nucleus of the zirconium grows by a subsequent heat treatment, so that Glass may be devitrified. Moreover, when the 1st coating film is comprised with the titanium oxide, when the crystal grain diameter of titanium grows large, there exists a possibility that the glass of a tube main body may be colored whitish.

  The second coating only needs to be composed of a hydrophobic lubricant or a surfactant having an HLB of 13 or less.

  Examples of the hydrophobic lubricant include olefin resins and high melting point waxes. This is because the olefin-based resin has a high glass transition point, and the high melting point wax has a high melting point, so that the second coating is not easily broken even when the glass tube is heat-treated.

  Examples of the olefin resin include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and the like.

  Examples of the high melting point wax include microcrystalline wax, paraffin wax, polyethylene wax, Fischer-Tropsch wax, polyethylene polypropylene copolymer, ester wax and the like. The high melting point wax preferably has a melting point of 100 to 450 ° C, more preferably 200 to 450 ° C, and still more preferably 300 to 450 ° C.

  Surfactants with HLB (Hydrophile-Lipophile Balance) of 13 or less include fatty acid salts, alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, alkyl sulfate triethanolamines, fatty acid ethanolamides, polyoxyethylene alkyls Examples include ethers and alkyltrimethylammonium salts. In addition, HLB here refers to the HLB value calculated by the Griffin method.

  In one embodiment of the glass tube for a fluorescent lamp according to the present invention, the alkaline earth metal oxide is at least one oxide selected from magnesium oxide and calcium oxide. In this case, the glass tube can be manufactured at a low cost. This is because magnesium oxide oxide and calcium oxide oxide can be obtained from a natural ore such as dolomite and thus can be obtained at a lower cost than other alkaline earth metal oxides.

  Moreover, in one aspect of the glass tube for a fluorescent lamp according to the present invention, the alkaline earth metal oxide is magnesium oxide and calcium oxide, and the molar ratio of the calcium oxide to the magnesium oxide is 0.5 to 3. It is characterized by that. In this case, it is difficult to devitrify, and the tube body can be made of glass with less alkaline component elution. Since calcium has a larger ionic radius than magnesium, it has a great effect of suppressing the elution of alkali components. On the other hand, when there is too much calcium, the crystal | crystallization of calcium and an alkali metal will arise and it will become easy to devitrify glass. Therefore, it is preferably within the range of the molar ratio.

  As shown in FIGS. 1 and 2, when the molar ratio of calcium oxide to magnesium oxide (CaO / MgO) is less than 0.5, the glass softening temperature or working temperature may not fall within the preferred range. Workability is likely to deteriorate. If the molar ratio of calcium oxide to magnesium oxide (CaO / MgO) exceeds 3, the glass may be devitrified.

  Moreover, in one aspect | mode of the glass tube for fluorescent lamps which concerns on this invention, the glass which comprises a tube main body contains 8-20 wt% of alkali metal oxides in total. When the content of the alkali metal oxide exceeds 20 wt%, the conductivity described later may exceed 57 μS / cm, and the glass tends to have a relatively large amount of elution of alkali components. If the content rate of an alkali metal oxide is less than 8 wt%, the working temperature of glass may not be in a suitable range, and workability tends to deteriorate.

Moreover, in one aspect of the glass tube for a fluorescent lamp according to the present invention, 50 wt% or more of the oxide constituting the first film has a tetragonal crystal structure. When a majority of the oxides constituting the first coating have a tetragonal crystal structure, the glass strength of the bulb can be further increased and the bulb can be made thinner. When the crystal structure of the oxide is a tetragonal system, the glass strength is increased because cristobalite, which is a crystal system of SiO ₂ , which is the main component of glass, has a tetragonal crystal structure, and thus forms a first film. This is because when the crystal structure of the oxide is the same tetragonal system, the film formability on the glass surface is improved. Further, if the crystal structure is a tetragonal system, the generated first film is firmly bonded to the glass, so that peeling or the like hardly occurs.

For oxide tin oxide constituting the first film, it is preferable the tin oxide is in a state of SnO ₂ instead of SnO. This is because SnO ₂ is stable as a tetragonal crystal, but SnO tends to turn into a cubic crystal. In addition, when the temperature of the glass tube to coat is 500 degreeC or more, it will be hard to be in the state of SnO.

  Moreover, in one aspect of the glass tube for a fluorescent lamp according to the present invention, the tube body has a wall thickness t [mm] and an outer diameter φ [mm] of t ≦ 0.7 or t / φ ≦ 0.42. It is characterized by satisfying the relationship. In this case, since the thickness is small, the valve is particularly easily damaged, and the configuration according to the present invention is effective.

  The fluorescent lamp according to the present invention includes a bulb produced using the fluorescent lamp glass tube described above. Therefore, it is hard to break.

  An illumination device according to the present invention includes the fluorescent lamp described above. Therefore, it is hard to break.

  The glass tube for a fluorescent lamp according to the present invention does not deteriorate the performance of increasing the glass strength of the coating even when the glass tube is heat-treated in the manufacturing process of the fluorescent lamp. Therefore, the bulb of the fluorescent lamp can be thinned.

The figure which shows the composition and characteristic of glass which comprise the tube main body of the glass tube for lamps concerning this Embodiment. The figure which shows the composition and characteristic of glass which comprise the tube main body of the glass tube for lamps concerning this Embodiment. The figure which shows the experimental result about the influence which the film thickness of a 1st film has on the glass strength and white turbidity of a glass tube Partially broken plan view showing a lamp according to the present embodiment The perspective view which shows schematic structure of the illuminating device which concerns on this Embodiment. It is a figure explaining the manufacturing method of a fluorescent lamp, (a) is a figure explaining a fluorescent substance application process, (b) is a figure explaining a sintering process, (c) is a valve sealing process. It is a figure explaining, (d) is a figure explaining a valve | bulb bending process. The figure for demonstrating the measuring method of the film thickness of a film Diagram for explaining the measurement method of alkali elution amount The figure which shows correlation with the electrical conductivity measured by the alkali elution amount measured by the alkali elution test method of JIS regulation, and the alkali elution test method which concerns on this application

  Hereinafter, a glass tube for a fluorescent lamp (hereinafter simply referred to as “glass tube”), a fluorescent lamp, and an illumination device according to an embodiment of the present invention will be described with reference to the drawings.

[Configuration of glass tube, fluorescent lamp, and lighting device]
<Glass tube>
The glass tube according to the present invention comprises a tube body, a first coating formed on at least the outer peripheral surface of the tube body, and a second coating laminated on the first coating.

  The tube main body preferably has a thickness t [mm] and an outer diameter φ [mm] satisfying a relationship of t ≦ 0.7 or t / φ ≦ 0.42. In particular, 0.4 ≦ t ≦ 0.6 and 1 ≦ φ ≦ 10 are preferable.

  The film thickness of the first coating is preferably 5 to 100 nm, and more preferably 5 to 50 nm. FIG. 3 is a diagram showing experimental results on the influence of the film thickness of the first coating film on the glass strength and white turbidity of the glass tube. As shown in FIG. 3, when the film thickness was 5 nm or more (Examples 14 to 20, 23 to 25), the glass strength was evaluated as “◯”, but when the film thickness was less than 5 nm (Example 21, 22) was an evaluation of “Δ” regarding the glass strength. Further, when the thickness of the first coating was 50 nm or less, white turbidity did not occur in the heated portion when the glass tube was heated in the bulb sealing step or the like, but when it exceeded 50 nm, white turbidity occurred in the heated portion. It is considered that the white turbidity is caused by the growth of tin oxide coating particles by heating. However, such white turbidity is not preferable because it causes poor appearance of the fluorescent lamp and further hinders the appearance inspection of scratches and the like.

  The film thickness of the second coating is preferably 10 to 300 nm. When the thickness of the first coating is 500 nm or more, or the thickness of the second coating is 500 nm or more, the visible light transmittance of the glass tube decreases. The transmittance is also reduced. As a result, the light extraction efficiency of the fluorescent lamp decreases, and the total luminous flux of the fluorescent lamp also decreases. On the other hand, when the thickness of the first coating is 5 nm or less, the fixability of the second coating is deteriorated. Further, when the thickness of the second coating is 5 nm or less, the scratch resistance of the bulb is lowered.

  Note that the first coating and the second coating may be formed not only on the outer peripheral surface of the tube body but also on the inner peripheral surface and the end surface. Further, the first coating and the second coating do not need to be formed over the entire outer peripheral surface, and may not be formed in a portion covered with a base when the bulb is formed.

The tube body is preferably made of glass having the following composition. Silicon oxide (SiO _2): 60~75wt%, aluminum oxide _{(Al 2 O 3): 0.5~5wt} %, boron oxide _{(B 2 O 3): 0~5wt} %, lithium oxide (Li ₂ O): 0.5~7wt%, sodium oxide _{(Na 2 O): 3~17wt%} , potassium oxide _{(K 2 O): 1~12wt%} , magnesium oxide (MgO): 1~4wt%, calcium oxide (CaO): 1 to 7.3 wt%, strontium oxide (SrO): 0 to 8 wt%, barium oxide (BaO): 0 to 10 wt%, zinc oxide (ZnO): 0 to 10 wt%, zirconium oxide (ZrO): 0 to 5 wt% Iron oxide (Fe ₂ O ₃ ): 0.01 to 0.2 wt%, antimony oxide (Sb ₂ O ₃ ): 0 to 1 wt%, cerium oxide (CeO ₂ ): 0 to 1 wt%.

SiO ₂ is a main component that forms the skeleton of the glass, and if it is too small, the viscosity of the glass is lowered and the processability is too poor. On the other hand, if the amount is too large, the viscosity of the glass becomes too hard to deform. A preferable range of the content of SiO ₂ is 60 to 75 wt%.

Al ₂ O ₃ is a component that improves chemical durability, and if it is too small, the chemical durability is deteriorated. On the other hand, if too much, the glass becomes inhomogeneous and the striae increase. A preferable range of the content of Al ₂ O ₃ is 0.5 to 5 wt%.

B ₂ O ₃ is an optional component and has an effect of reducing devitrification by lowering the expansion coefficient when added in a small amount. However, if the amount is too large, the working point temperature decreases and the working temperature range becomes too narrow, making machining difficult. A preferable range of the content of B ₂ O ₃ is 0 to 5 wt%.

Na ₂ O has the effect of lowering the viscosity and increasing the expansion coefficient when added, and if the amount is too small, the effect cannot be obtained. Moreover, when too much, chemical durability will worsen. A preferable range of the content of Na ₂ O is 3 to 17 wt%.

When K ₂ O is added, the same effect as Na ₂ O can be obtained, but the degree of influence of an increase in expansion coefficient is greater than that of Na ₂ O. Further, by coexisting with Na ₂ O, exert mixed alkali effect, also exhibits the effect of increasing the electrical resistivity. If the amount is too small, the effect cannot be obtained. If the amount is too large, the expansion coefficient becomes too large. A preferable range of the content of K ₂ O is 1 to 12 wt%.

When Li ₂ O is added, the same effect as Na ₂ O or K ₂ O can be obtained, but the increase in expansion coefficient is smaller than that of Na ₂ O. Further, by coexisting with Na ₂ O or K ₂ O, a further mixed alkali effect is exhibited, and an effect of further increasing the electrical resistivity is also exhibited. If the amount is too small, the effect cannot be obtained. If the amount is too large, the glass may be phase-separated. A preferable range of the content of Li ₂ O is 0.5 to 7 wt%.

  MgO and CaO have the effect of improving chemical durability by adding in addition to the above-described effect of suppressing the elution of alkali components. If the amount is too small, the effect cannot be obtained. If the amount is too large, the glass may be devitrified. A preferable range of the MgO content is 1 to 4 wt%, and a preferable range of the CaO content is 1 to 7.3 wt%.

  SrO, BaO, and ZnO are substances that have an effect on improving the electrical resistivity of the glass in addition to the above-described effect of suppressing the elution of alkali components, and also provide electrical insulation. If the content is more than 10 wt%, the glass tends to be devitrified. Preferred ranges are 0 to 8 wt% for SrO, 0 to 10 wt% for BaO, and 0 to 10 wt% for ZnO. Within this range, a more suitable glass for a fluorescent lamp can be obtained.

  ZrO is an optional component and has the effect of increasing hardness when added. If too much, the glass may crystallize. A preferable range of the content of ZrO is 0 to 5 wt%.

Fe ₂ O ₃ is a substance mixed as an impurity of various raw materials, but the amount of Fe ₂ O ₃ can be adjusted by refining the raw materials and can absorb ultraviolet rays when added. If the amount is too small, the effect cannot be obtained. If the amount is too large, the glass may be colored. A preferable range of the content of Fe ₂ O ₃ is 0.01 to 0.2 wt%.

Sb ₂ O ₃ is an optional component and has an effect of efficiently clarifying the gas generated from the raw material in the glass melting furnace, but if it is too much, the glass may be colored. A preferable range of the content of Sb ₂ O ₃ is 0 to 1 wt%.

CeO ₂ is an optional component and has an effect of absorbing ultraviolet rays when added, but if it is too much, so-called solarization, which is colored by ultraviolet irradiation, may occur. A preferable range of the CeO ₂ content is 0 to 1 wt%.

<Fluorescent lamp>
FIG. 4 is a partially broken plan view showing an annular fluorescent lamp according to one embodiment of the present invention. As shown in FIG. 4, an annular fluorescent lamp (FCL30ECW / 28) 10 according to an embodiment of the present invention includes an annular bulb 20 and stems 30 and 31 ′ sealed at both ends of the bulb 20. , And a base 40 attached across the both ends.

  The bulb 20 is obtained by processing a glass tube according to the present invention. A protective layer (not shown) and a phosphor layer (not shown) are sequentially laminated on the inner surface of the bulb 20 to supply mercury vapor therein. Amalgam grains 21 and argon gas which is an example of a rare gas are enclosed. Mounted on each stem 30, 30 'is an electrode 31, 31' comprising a filament coil and a pair of lead wires. The base 40 includes a main body 41 in which the end of the valve 20 is accommodated and a plurality of connection pins 42 provided on the main body 41.

<Lighting device>
FIG. 5 is a perspective view showing an illumination apparatus according to an embodiment of the present invention. As shown in FIG. 5, the illuminating device 100 which concerns on this Embodiment is provided with the fluorescent lamp 10 mentioned above as a light source. The fluorescent lamp 1 is accommodated in the apparatus main body 101 and is turned on by a lighting means 102 attached to the apparatus main body 101.

[Method of manufacturing glass tube and lamp]
<Glass tube manufacturing method>
First, a plurality of types of glass raw materials are prepared within the above composition range to obtain a raw material mixture. Next, the raw material mixture is put into a glass melting furnace and melted at 1500 to 1600 ° C. to vitrify to obtain a glassy glass melt. Thereafter, the glass melt is formed into a tubular shape by a tube drawing method such as the Danner method, and cut into a predetermined size to obtain a glass tube.

  The formation of the first film is performed by spraying vapor generated by heating an organic metal on a glass tube being drawn in a draft chamber. For example, the organic metal is heated at 180 ° C. to vaporize 10 g per minute, and the obtained vapor is sprayed on a glass tube at a flow rate of 5 L / min for 1 second to form a first coating. The film thickness of the first coating can be controlled by adjusting the vaporization temperature, the amount of organic metal used, the spraying speed, the spraying time, and the like. The first coating may be formed by a method in which an organic metal dissolved in water or an organic solvent is sprayed, or a method in which the tube body is immersed and applied in the dissolved material.

  As the organic metal used for forming the first film, for example, an organic metal containing tin, titanium, zirconium, or silicon as a metal component is used. Specific examples include tin tetrachloride, titanium tetrachloride, zirconium tetrachloride, silicon tetrachloride, dimethyldichlorotin, dimethyldichlorotitanium, dimethyldichlorozirconium, dimethyldichlorosilicon, acetylacetonetin, acetylacetone titanium, acetylacetonezirconium, and acetylacetonesilicon. Can be mentioned.

  When the hydrophobic lubricant is used, the second coating is formed by, for example, emulsifying the hydrophobic lubricant in water or an organic solvent, and applying the prepared liquid to the glass tube to form a coating. As a coating method, a spraying method by spraying or a method of immersing and applying a tube body is used. Moreover, when using surfactant, it coats using the spraying method by spraying and the method of immersing and apply | coating a pipe | tube main body, for example.

<Lamp manufacturing method>
6A and 6B are diagrams illustrating a method for manufacturing a fluorescent lamp, wherein FIG. 6A is a diagram illustrating a phosphor coating process, FIG. 6B is a diagram illustrating a sintering process, and FIG. 6C is a bulb. It is a figure explaining a sealing process, (d) is a figure explaining a valve | bulb bending process.

  First, in the phosphor coating step, as shown in FIG. 6A, a phosphor suspension 50 of three wavelengths is poured into a glass tube 21 having a protective film formed on the inner surface, and the inner surface of the glass tube 21 is moved. Wet with the phosphor suspension 50. Next, hot air (25 to 30 ° C.) is blown into the glass tube 21 to dry the phosphor suspension 50, and then the atmosphere is controlled to about 550 to 660 ° C. as shown in FIG. 6B. The phosphor layer is formed by baking for about 1 minute in the furnace. Thus, since a glass tube is heat-processed in a sinter process, an alkali component tends to elute.

  Next, in the bulb sealing step, after removing the phosphor layers in the vicinity of both ends of the glass tube 21, as shown in FIG. 6 (c), stems 30 and 30 'are inserted into the both ends and sealed. To do. In the subsequent bulb bending step, the straight glass tube 21 is bent into an annular shape in a furnace whose atmosphere is controlled at about 700 to 900 ° C., as shown in FIG. As described above, since the glass tube is heat-treated in the bulb bending process, the alkali component is likely to be eluted.

  Thereafter, in the exhaust process, the impure gas is exhausted from the inside of the valve 20 through the unsealed exhaust pipe 32, and the inside of the valve 20 is brought to a state close to a vacuum, and then argon gas is introduced. Further, in the amalgam sealing step, amalgam particles 21 are introduced into the valve from the exhaust pipe 32.

[Evaluation methods]
The glass tube for a fluorescent lamp was evaluated by the following method.

<Film thickness>
The film thickness of the coating was measured using a hot end coating meter (HOT END COATING MEASUREMENT SYSTEM: HECM-S) manufactured by American Glass Research.

  FIG. 7 is a diagram for explaining a method of measuring the film thickness. As shown in FIG. 7 (a), a glass tube cut into 20cm is prepared as a sample, and as shown in FIG. The film thickness was measured at 4 points with a uniform interval in the direction (with an interval of about 90 ° rotation angle) (12 points in total), and the average of these 12 points was taken as the film thickness. The incident angle of light at each point was 45 °.

  In the hot-end coating meter, the film thickness is expressed by ctu (coating thickness units), which is a unique unit, and 1 ctu is 0.2 to 0.3 nm in SI units. In this application, it is converted as 1 ctu = 0.25 nm.

<Glass strength>
First, in the experiment, a straight glass tube having an outer diameter of 4 mm and an inner diameter of 3 mm and having a first coating and a second coating formed on the outer peripheral surface was used. The first coating has a thickness of 100 nm composed of tin oxide by heating dimethyldichlorotin powder at 120 ° C. for 1 minute and blowing the generated vapor onto the glass tube being drawn in the draft chamber. Formed. The 2nd film formed the thing of the film thickness of 30 nm which consists of various materials as shown in FIG.1 and FIG.2 by spraying with a spray with respect to the glass tube in tube drawing.

  Next, the glass tube on which the coating has been formed is placed in a quartz tube having an inner diameter of 20 mm, and the quartz tube is rotated at a rotation speed of 20 rpm for 5 minutes in an environment of 500 ° C., and the glass tube and the quartz tube are rubbed together. Injured the surface of the glass tube.

  Then, the bending strength of the glass tube after an injury was measured using Autograph AG-IS (made by Shimadzu Corporation). The bending strength was measured by fixing the glass tube with a left and right span of 40 mm, applying a load at a load rate of 1 mm / min to the center of the glass tube, and obtaining a value when the glass tube was broken.

  When the bending strength is reduced by 30% or more due to scratching, the glass strength is evaluated as “x” as insufficient, and when the bending strength is reduced by less than 30%, the glass strength is assumed to be sufficient. It was evaluated as “Δ” (when the bending strength was reduced by 15% or more and less than 30%) or “◯” (when the bending strength was reduced by 0% or more and less than 15%). The reason why the glass strength is insufficient when the bending strength is reduced by 30% or more is that when a fluorescent lamp is manufactured using a glass tube whose bending strength is reduced by 30% or more, the yield in the process is increased. It is because it falls remarkably.

<White turbidity>
The white turbidity was evaluated by visual observation. When white turbidity was not visually observed, “◯” was evaluated, and when white turbidity was visually observed, “×” was evaluated.

<Abrasion resistance>
The scratch resistance was evaluated according to the following procedure. First, two glass tubes cut into 10 cm were brought into contact at an angle of 90 ° and rubbed 20 times. Thereafter, the rubbed portions were magnified 4 times with an optical microscope and observed. As a result, “X” was evaluated for those in which formation of scratches was confirmed, and “O” was evaluated for those in which scratches were not confirmed.

<Softening point temperature and working point temperature>
In order to measure the softening point temperature and working point temperature of the glass, a sample was prepared by the following procedure. First, the raw material mixture obtained by preparing the glass raw material is transferred to a platinum crucible, and the platinum crucible is melted in an electric furnace at 1500 ° C. for 3 hours to be vitrified. After melting, it is poured into a mold and gradually cooled (annealed) over 12 hours so that sufficient strain can be removed. The molded glass lump was molded into a sample shape suitable for each measurement described below using a cutting machine or the like, and each measurement was performed.

The softening point temperature is a temperature at which the viscosity of the glass becomes 10 ^7.65 dPa · s, and when the temperature becomes equal to or higher than the temperature, the glass obtains fluidity. The softening point temperature is preferably in the range of 650 ° C. to 720 ° C. and more preferably in the range of 670 to 700 ° C. for fluorescent lamps. When the softening point temperature is lower than 650 ° C., the bulb is deformed by the heat when heated in order to volatilize the binder of the phosphor suspension in the phosphor baking step. On the other hand, if the softening point temperature is higher than 720 ° C., the glass tube must be heated at the time of sealing, and the combustion capacity of the melting furnace must be increased.

The working point temperature is the temperature at which the viscosity of the glass is 10 ⁴ dPa · s. Below this temperature, the glass is processed. The working point temperature is preferably in the range of 960 ° C. to 1050 ° C. and more preferably in the range of 960 to 1000 ° C. for fluorescent lamps. When the working temperature is lower than 1000 ° C., the working temperature range becomes narrow, so that workability is poor. On the other hand, when the working point temperature is higher than 1050 ° C., the temperature at which the glass melts becomes too high, so that the workability is deteriorated and the cost of the melting step is also increased.

<Alkali elution amount>
As a method for measuring the amount of alkali elution, a test method for a glass instrument for chemical analysis based on JIS (Japanese Industrial Standard JIS R 3502) is generally used. This method will be briefly explained. First, a glass sample is pulverized into a powder (particle size: 250 to 420 μm) using a mortar or the like to obtain a crushed glass, and then the crushed glass is washed with ethyl alcohol. Then, the glass fine powder is removed from the pulverized glass, and the washed glass pulverized product is heated in a boiling water bath for 60 minutes to elute alkali components from the pulverized glass to obtain an alkali eluate. Then, the alkali eluate is neutralized and titrated with sulfuric acid, and the alkali elution amount is converted from the obtained titration value.

  In such a test method based on JIS, if washing with ethyl alcohol is insufficient, glass fine powder remains in the crushed glass, and therefore the total surface area of the glass in distilled water is greatly increased due to the presence of the glass fine powder. There is a problem that the amount of alkali elution cannot be measured accurately. In addition, complicated operations such as pulverizing the glass sample, removing the fine glass powder by washing, and neutralizing titration are required. Therefore, a more accurate and simple method for measuring the amount of alkali elution is desired.

  Accordingly, the inventors newly established a method for measuring the amount of alkali elution that is more accurate and simpler than the test method based on JIS. In the measurement method according to the present invention, a block-shaped glass sample is immersed in distilled water to elute alkali components from the glass sample into distilled water, and the conductivity of the obtained alkaline eluate is measured. The amount of alkali elution is converted.

  FIG. 8 is a diagram for explaining a method for measuring an alkali elution amount according to the present invention. A specific procedure of the measurement method according to the present invention will be described with reference to FIG.

  First, a glass sample is cut into a block shape, and left for 45 to 50 hours in a constant temperature and humidity chamber maintained at a temperature of 75 to 85 ° C. and a humidity of 85 to 95%, and then subjected to moisture treatment. In order to increase the measurement accuracy, it is more preferable that the temperature, humidity, and standing time in the impregnation treatment are 80 ° C., 90%, and 48 hours, which are values near the center of each range.

  Next, as shown in FIG. 8, 100 ml of 70 to 80 ° C. distilled water 2 is stored in the water tank 1, and the glass sample 3 that has been subjected to the moisture treatment is immersed in the distilled water 2 for 1 hour. In the measuring method according to the present invention, since alkaline components are eluted in distilled water 2 having a relatively low temperature of 70 to 80 ° C., a test method based on JIS for forcibly eluting alkaline components in boiling distilled water is used. In addition, it is possible to measure the alkali elution amount more in line with the actual usage form of glass.

Glass sample 3, the sum of the surface area within the range defined by 4500～5500Mm ^2, is preferably adjusted to about 5000 mm ² immersion. For example, eight glass samples 3 cut into a rectangular parallelepiped shape of about 15 × 15 × 2.5 mm are immersed.

  Thereafter, the glass sample 3 is removed from the distilled water 2 to obtain an alkaline eluate. And the said alkali elution liquid is stabilized at 25 degreeC, and conductivity is measured using the commercially available handy type sensor type liquid immersion type conductivity measuring machine 4 (brand name: Twincond B-173).

  FIG. 9 is a graph showing the correlation between the alkali elution amount measured by the test method based on JIS and the conductivity measured by the test method according to the present invention. The alkali elution amount and the electrical conductivity are in a correlation as shown in FIG. Although it is considered that glass having an alkali elution amount of 270 μg / g or less is suitable for a bulb of a fluorescent lamp, as can be seen from FIG. 9, the conductivity corresponding to an alkali elution amount of 270 μg / g is 57 μS / g. cm. Therefore, it can be said that a glass having a conductivity of 57 μS / cm or less is suitable as a glass for a bulb.

  That is, the electrical conductivity is a numerical value indirectly indicating the alkali elution amount of the glass, and in order to be a glass suitable for a fluorescent lamp, it can be said that it is preferably 57 μS / cm or less at 25 ° C. When the conductivity is higher than 57 μ / cm, various problems due to the formation of amalgam become remarkable.

  Since the said measuring method uses a block-shaped glass sample, it is easy to control the sum total of the surface area of the glass immersed in distilled water. Therefore, the alkali elution amount can be measured with higher accuracy than the test method based on JIS. In addition, since the measurement method according to the present invention measures the alkali elution amount based on the conductivity, the measurement accuracy does not deteriorate even if the alkali elution amount increases.

  In addition, since the above-described measurement method immerses the cut block-shaped glass sample in distilled water, it is not necessary to pulverize the glass sample into powder or wash the crushed glass. In addition, the measurement of the conductivity of the alkaline eluate can be performed by a simple operation of just immersing the electrode of the conductivity measuring device 4 in the alkaline eluate, and no complicated neutralization titration work is required. Therefore, the operation is simpler than the measurement method based on JIS.

<Devitrification>
When the glass was melted and vitrified, it was visually confirmed whether or not crystals were generated on the glass and devitrified. Evaluation was made that “O” was not devitrified and “x” was devitrified.

<Ratio of tetragonal crystals>
First, in the experiment, a straight glass tube having an outer diameter of 4 mm and an inner diameter of 3 mm and having a first film formed on the outer peripheral surface was used. The first coating was formed by heating the powder of dimethyldichlorotin at 120 ° C. for 1 minute and blowing the generated vapor onto the glass tube being drawn in the draft chamber to a film thickness of 100 nm.

Next, the first film as it was formed on the glass tube was observed with an X-ray diffractometer (RINT2000, manufactured by Rigaku Corporation), and the crystal structure of the oxide constituting the first film was confirmed. The measurement was performed under the conditions of a scan speed of 6 ° / min and a measurement range of 0 ° to 90 °, and the ratio of SnO and SnO ₂ crystals was evaluated. SnO is mainly tetragonal as a crystal structure, but has a cubic crystal structure as a partial transformation, whereas SnO ₂ has only a tetragonal crystal structure. Therefore, it is preferable as the first coat of glass in the state of SnO _2. Thereby, the concealability of the first coating on the glass surface is improved, and a greater effect can be obtained. In particular, the ratio SnO ₂ / SnO is preferably 1 or more.

[Modification]
As described above, the fluorescent lamp and the fluorescent lamp glass tube according to the present invention have been specifically described based on the embodiments. However, the fluorescent lamp glass tube, the fluorescent lamp, and the lighting device according to the present invention are described above. It is not limited to.

  The glass tube for a fluorescent lamp according to the present invention is suitable not only for producing a bulb but also for producing a flare, an exhaust tube, or the like that is heat-treated at the time of processing and is required to be thin. The glass constituting the tube body may be soft glass or hard glass, but the configuration of the present invention is particularly effective in the case of soft glass having low glass strength.

  The fluorescent lamp according to the present invention is not limited to the above embodiment, but a straight tube fluorescent lamp, an annular fluorescent lamp, a cold cathode fluorescent lamp, a double annular fluorescent lamp, a square fluorescent lamp, and a double square fluorescent lamp. Widely used for fluorescent lamps such as lamps and twin fluorescent lamps.

  The lighting device according to the present invention is not limited to the above embodiment. For example, it can be widely used in lighting devices such as indoor lighting devices, outdoor lighting devices, desk lighting, portable lighting, display light sources, liquid crystal screen backlights, and image reading lighting.

  The glass tube for a fluorescent lamp according to the present invention can be widely used for lighting applications.

DESCRIPTION OF SYMBOLS 10 Lamp 20 Bulb 21 Fluorescent lamp glass tube 22 Tube body 23 1st film 24 2nd film 100 Illumination device

  The present invention relates to a glass tube for a fluorescent lamp, a fluorescent lamp, and an illumination device.

In recent years, resource saving and CO ₂ emission reduction are required from the viewpoint of global environmental protection. As a method for saving resources and reducing CO ₂ emissions in the fluorescent lamp field, it is conceivable to reduce the thickness of a glass bulb (hereinafter simply referred to as “bulb”). That is, when the bulb is thinned, the amount of glass used as the bulb material is reduced, so that resource saving can be realized. Moreover, since the amount of combustion gas consumed in the melting furnace during glass production is reduced by reducing the amount of glass used, it is possible to reduce CO ₂ emissions.

  By the way, it is expected that the glass strength decreases when the bulb is thinned. Therefore, a device for improving the glass strength of the bulb is required. In Patent Document 1, as a method for improving the glass strength, it is disclosed to improve the scratch resistance of the glass container by forming a film made of a lubricant on the surface of the glass container and reducing the friction coefficient of the surface. Has been. Since the glass has a very high strength unless the surface is scratched, the glass strength of the glass container is improved when the scratch resistance is improved and the scratch becomes difficult to be scratched.

  Further, Patent Document 1 discloses that it is preferable to use a hydrophobic lubricant for the coating, and even if a hydrophilic lubricant is used, the scratch resistance of the glass container is not improved so much. Further, since hydrophobic lubricants have poor fixability to glass, it is also disclosed that a film made of a metal oxide is first formed on the glass surface, and a film made of a hydrophobic lubricant is formed on the film. Has been.

Japanese Patent No. 3895519

  However, when the above method was applied to produce a bulb for a fluorescent lamp, the glass strength of the bulb was formed despite the formation of a metal oxide coating and a hydrophobic lubricant coating on the bulb surface. Did not improve. Therefore, it has been difficult to reduce the thickness of the valve.

In view of the above-described problems, the present invention mainly aims to provide a fluorescent lamp glass tube capable of reducing the thickness of a fluorescent lamp bulb. Another object of the present invention is to provide a fluorescent lamp and a lighting device suitable for resource saving and CO ₂ emission reduction.

  In order to achieve the above object, a glass tube for a fluorescent lamp according to the present invention is a tube body made of glass containing 60 to 75 wt% silicon oxide and 5 to 18 wt% alkaline earth metal oxide. And a first coating formed on at least the outer peripheral surface of the tube main body and composed of at least one oxide selected from tin oxide, titanium oxide, zirconium oxide and silicon oxide, and laminated on the first coating. And a second coating film comprising a hydrophobic lubricant or a surfactant having an HLB of 13 or less.

  In addition, the content rate of the oxide described in this application is the value converted into an oxide unless there is particular description. Moreover, the numerical value range described in the present application includes a lower limit value and an upper limit value. For example, when the numerical range is 60 to 75 wt%, the numerical range includes 60 wt% and 75 wt%. Further, the glass constituting the tube main body and the oxide constituting the first coating may contain substances other than those described above to the extent of impurities.

In the glass tube for a fluorescent lamp according to the present invention, since the glass constituting the tube main body contains an alkaline earth metal oxide of 5 wt% or more, the bulb of the fluorescent lamp can be thinned.
Alkali metals exist as monovalent metal ions in the glass, and thus have a high mobility in the network structure of the glass. In particular, sodium has a high mobility because of its small atomic radius. As described above, the alkali metal having a high mobility is easily eluted from the glass to the glass surface as an alkali component. When the first coating is subjected to a chemical attack (chemical damage) by the alkali component thus eluted, the polarity of the coating surface increases, so that the hydrophilicity of the first coating increases, and as a result, the fixability of the second coating decreases. . As a result, the coefficient of friction on the valve surface increases, so that the scratch resistance of the valve decreases and the glass strength of the valve decreases. The inventors have described that the glass strength of the bulb is not improved even if the first coating made of metal oxide and the second coating made of a hydrophobic lubricant are formed on the surface of the bulb of the fluorescent lamp. I found it.

  In addition, it is not restricted to the heat processing by a sinter process that an alkaline component elutes from the glass of a tube main body. In the manufacturing process of a fluorescent lamp, there are other processes for heat-treating the glass tube, such as a bulb bending step for bending the bulb, a bulb sealing step for sealing the end of the glass tube, and a connection step for connecting the glass tubes together. In addition, the alkali component is easily eluted by these steps. The bent valve is a non-linear valve formed by bending a straight glass tube, such as an annular valve, a U-shaped valve, or a spiral valve.

  The glass tube for a fluorescent lamp according to the present invention suppresses the elution of the alkaline component by the alkaline earth metal. Since the alkaline earth metal exists as a divalent metal ion in the glass, the mobility in the network structure of the glass is small. Also, the ion radius is relatively large. Therefore, the movement of alkali metal in the glass is inhibited. If the alkaline earth metal is contained in an amount of 5 wt% or more, even if the glass tube is heat-treated in the manufacturing process of the fluorescent lamp, the alkali component is hardly eluted from the glass of the tube body. Therefore, the first coating is less susceptible to chemical attack, and as a result, the fixability of the second coating does not decrease, so the scratch resistance of the bulb does not decrease and the glass strength does not decrease. In addition, as for the content rate of alkaline-earth metal oxide, 5-18 wt% is more preferable, It is more preferable that it is 10-18 wt%, 12-18 wt% is the most preferable.

  1 and 2 are diagrams showing the composition and characteristics of glass constituting the tube body of the glass tube for lamp according to the embodiment. As shown in FIGS. 1 and 2, when the alkaline earth metal content of the glass constituting the tube main body was 5 wt% or more, the bulb had high scratch resistance, and the bulb had sufficient glass strength. On the other hand, when the content was less than 5 wt%, the scratch resistance of the bulb was low and the glass strength of the bulb was insufficient.

The glass tube for a fluorescent lamp according to the present invention has good workability because the content of the alkaline earth metal oxide in the glass constituting the tube body is 18 wt% or less.
As the content of alkaline earth metal increases, the viscosity of glass increases with temperature. That is, the glass is easy to cool and has poor processability. When the tube body is made of such glass, the workability of the glass tube is also deteriorated. In order to obtain a glass tube with good workability, it is necessary that the content of alkaline earth metal in the glass constituting the tube body be 18 wt% or less. In addition, the glass with good workability has a softening temperature in the range of 650 to 720 ° C. and a working temperature in the range of 960 to 1050 ° C. More preferably, the softening temperature is in the range of 670 to 700 ° C, and the working temperature is in the range of 960 to 1000 ° C.

  As shown in FIGS. 1 and 2, when the alkaline earth metal content was 18 wt% or less, a glass with good workability in which the softening temperature and the working temperature were within the above ranges was obtained. On the other hand, when the said content rate exceeded 18 wt%, it became glass with bad workability.

  Although the 1st film should just be comprised with the at least 1 sort (s) of oxide chosen from a tin oxide, a titanium oxide, a zirconium oxide, and a silicon oxide, it is preferable that it is comprised especially with a tin oxide. If the first coating is made of tin oxide, the glass of the tube body will not be colored or devitrified. On the other hand, when the first coating is composed of zirconium oxide, the zirconium reacts with a component in the glass to act as a crystal nucleation product, and the crystal nucleus of the zirconium grows by a subsequent heat treatment, so that Glass may be devitrified. Moreover, when the 1st coating film is comprised with the titanium oxide, when the crystal grain diameter of titanium grows large, there exists a possibility that the glass of a tube main body may be colored whitish.

The second coating only needs to be composed of a hydrophobic lubricant or a surfactant having an HLB of 13 or less.
Examples of the hydrophobic lubricant include olefin resins and high melting point waxes. This is because the olefin-based resin has a high glass transition point, and the high melting point wax has a high melting point, so that the second coating is not easily broken even when the glass tube is heat-treated.

Examples of the olefin resin include polyethylene, polypropylene, polybutene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and the like.
Examples of the high melting point wax include microcrystalline wax, paraffin wax, polyethylene wax, Fischer-Tropsch wax, polyethylene polypropylene copolymer, ester wax and the like. The high melting point wax preferably has a melting point of 100 to 450 ° C, more preferably 200 to 450 ° C, and still more preferably 300 to 450 ° C.

  Surfactants with HLB (Hydrophile-Lipophile Balance) of 13 or less include fatty acid salts, alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, alkyl sulfate triethanolamines, fatty acid ethanolamides, polyoxyethylene alkyls Examples include ethers and alkyltrimethylammonium salts. In addition, HLB here refers to the HLB value calculated by the Griffin method.

  In one embodiment of the glass tube for a fluorescent lamp according to the present invention, the alkaline earth metal oxide is at least one oxide selected from magnesium oxide and calcium oxide. In this case, the glass tube can be manufactured at a low cost. This is because magnesium oxide oxide and calcium oxide oxide can be obtained from a natural ore such as dolomite and thus can be obtained at a lower cost than other alkaline earth metal oxides.

  Moreover, in one aspect of the glass tube for a fluorescent lamp according to the present invention, the alkaline earth metal oxide is magnesium oxide and calcium oxide, and the molar ratio of the calcium oxide to the magnesium oxide is 0.5 to 3. It is characterized by that. In this case, it is difficult to devitrify, and the tube body can be made of glass with less alkaline component elution. Since calcium has a larger ionic radius than magnesium, it has a great effect of suppressing the elution of alkali components. On the other hand, when there is too much calcium, the crystal | crystallization of calcium and an alkali metal will arise and it will become easy to devitrify glass. Therefore, it is preferably within the range of the molar ratio.

  As shown in FIGS. 1 and 2, when the molar ratio of calcium oxide to magnesium oxide (CaO / MgO) is less than 0.5, the glass softening temperature or working temperature may not fall within the preferred range. Workability is likely to deteriorate. If the molar ratio of calcium oxide to magnesium oxide (CaO / MgO) exceeds 3, the glass may be devitrified.

  Moreover, in one aspect | mode of the glass tube for fluorescent lamps which concerns on this invention, the glass which comprises a tube main body contains 8-20 wt% of alkali metal oxides in total. When the content of the alkali metal oxide exceeds 20 wt%, the conductivity described later may exceed 57 μS / cm, and the glass tends to have a relatively large amount of elution of alkali components. If the content rate of an alkali metal oxide is less than 8 wt%, the working temperature of glass may not be in a suitable range, and workability tends to deteriorate.

Moreover, in one aspect of the glass tube for a fluorescent lamp according to the present invention, 50 wt% or more of the oxide constituting the first film has a tetragonal crystal structure. When a majority of the oxides constituting the first coating have a tetragonal crystal structure, the glass strength of the bulb can be further increased and the bulb can be made thinner. When the crystal structure of the oxide is a tetragonal system, the glass strength is increased because cristobalite, which is a crystal system of SiO ₂ , which is the main component of glass, has a tetragonal crystal structure, and thus forms a first film. This is because when the crystal structure of the oxide is the same tetragonal system, the film formability on the glass surface is improved. Further, if the crystal structure is a tetragonal system, the generated first film is firmly bonded to the glass, so that peeling or the like hardly occurs.

For oxide tin oxide constituting the first film, it is preferable the tin oxide is in a state of SnO ₂ instead of SnO. This is because SnO ₂ is stable as a tetragonal crystal, but SnO tends to turn into a cubic crystal. In addition, when the temperature of the glass tube to coat is 500 degreeC or more, it will be hard to be in the state of SnO.

  Moreover, in one aspect of the glass tube for a fluorescent lamp according to the present invention, the tube body has a wall thickness t [mm] and an outer diameter φ [mm] of t ≦ 0.7 or t / φ ≦ 0.42. It is characterized by satisfying the relationship. In this case, since the thickness is small, the valve is particularly easily damaged, and the configuration according to the present invention is effective.

The fluorescent lamp according to the present invention includes a bulb produced using the fluorescent lamp glass tube described above. Therefore, it is hard to break.
An illumination device according to the present invention includes the fluorescent lamp described above. Therefore, it is hard to break.

  The glass tube for a fluorescent lamp according to the present invention does not deteriorate the performance of increasing the glass strength of the coating even when the glass tube is heat-treated in the manufacturing process of the fluorescent lamp. Therefore, the bulb of the fluorescent lamp can be thinned.

The figure which shows the composition and characteristic of glass which comprise the tube main body of the glass tube for lamps concerning this Embodiment. The figure which shows the composition and characteristic of glass which comprise the tube main body of the glass tube for lamps concerning this Embodiment. The figure which shows the experimental result about the influence which the film thickness of a 1st film has on the glass strength and white turbidity of a glass tube Partially broken plan view showing a lamp according to the present embodiment The perspective view which shows schematic structure of the illuminating device which concerns on this Embodiment. It is a figure explaining the manufacturing method of a fluorescent lamp, (a) is a figure explaining a fluorescent substance application process, (b) is a figure explaining a sintering process, (c) is a valve sealing process. It is a figure explaining, (d) is a figure explaining a valve | bulb bending process. The figure for demonstrating the measuring method of the film thickness of a film Diagram for explaining the measurement method of alkali elution amount The figure which shows correlation with the electrical conductivity measured by the alkali elution amount measured by the alkali elution test method of JIS regulation, and the alkali elution test method which concerns on this application

Hereinafter, a glass tube for a fluorescent lamp (hereinafter simply referred to as “glass tube”), a fluorescent lamp, and an illumination device according to an embodiment of the present invention will be described with reference to the drawings.
[Configuration of glass tube, fluorescent lamp, and lighting device]
<Glass tube>
The glass tube according to the present invention comprises a tube body, a first coating formed on at least the outer peripheral surface of the tube body, and a second coating laminated on the first coating.

  The tube main body preferably has a thickness t [mm] and an outer diameter φ [mm] satisfying a relationship of t ≦ 0.7 or t / φ ≦ 0.42. In particular, 0.4 ≦ t ≦ 0.6 and 1 ≦ φ ≦ 10 are preferable.

  The film thickness of the first coating is preferably 5 to 100 nm, and more preferably 5 to 50 nm. FIG. 3 is a diagram showing experimental results on the influence of the film thickness of the first coating film on the glass strength and white turbidity of the glass tube. As shown in FIG. 3, when the film thickness was 5 nm or more (Examples 14 to 20, 23 to 25), the glass strength was evaluated as “◯”, but when the film thickness was less than 5 nm (Example 21, 22) was an evaluation of “Δ” regarding the glass strength. Further, when the thickness of the first coating was 50 nm or less, white turbidity did not occur in the heated portion when the glass tube was heated in the bulb sealing step or the like, but when it exceeded 50 nm, white turbidity occurred in the heated portion. It is considered that the white turbidity is caused by the growth of tin oxide coating particles by heating. However, such white turbidity is not preferable because it causes poor appearance of the fluorescent lamp and further hinders the appearance inspection of scratches and the like.

  The film thickness of the second coating is preferably 10 to 300 nm. When the thickness of the first coating is 500 nm or more, or the thickness of the second coating is 500 nm or more, the visible light transmittance of the glass tube decreases. The transmittance is also reduced. As a result, the light extraction efficiency of the fluorescent lamp decreases, and the total luminous flux of the fluorescent lamp also decreases. On the other hand, when the thickness of the first coating is 5 nm or less, the fixability of the second coating is deteriorated. Further, when the thickness of the second coating is 5 nm or less, the scratch resistance of the bulb is lowered.

  Note that the first coating and the second coating may be formed not only on the outer peripheral surface of the tube body but also on the inner peripheral surface and the end surface. Further, the first coating and the second coating do not need to be formed over the entire outer peripheral surface, and may not be formed in a portion covered with a base when the bulb is formed.

The tube body is preferably made of glass having the following composition. Silicon oxide (SiO _2): 60~75wt%, aluminum oxide _{(Al 2 O 3): 0.5~5wt} %, boron oxide _{(B 2 O 3): 0~5wt} %, lithium oxide (Li ₂ O): 0.5~7wt%, sodium oxide _{(Na 2 O): 3~17wt%} , potassium oxide _{(K 2 O): 1~12wt%} , magnesium oxide (MgO): 1~4wt%, calcium oxide (CaO): 1 to 7.3 wt%, strontium oxide (SrO): 0 to 8 wt%, barium oxide (BaO): 0 to 10 wt%, zinc oxide (ZnO): 0 to 10 wt%, zirconium oxide (ZrO): 0 to 5 wt% Iron oxide (Fe ₂ O ₃ ): 0.01 to 0.2 wt%, antimony oxide (Sb ₂ O ₃ ): 0 to 1 wt%, cerium oxide (CeO ₂ ): 0 to 1 wt%.

SiO ₂ is a main component that forms the skeleton of the glass, and if it is too small, the viscosity of the glass is lowered and the processability is too poor. On the other hand, if the amount is too large, the viscosity of the glass becomes too hard to deform. A preferable range of the content of SiO ₂ is 60 to 75 wt%.

Al ₂ O ₃ is a component that improves chemical durability, and if it is too small, the chemical durability is deteriorated. On the other hand, if too much, the glass becomes inhomogeneous and the striae increase. A preferable range of the content of Al ₂ O ₃ is 0.5 to 5 wt%.

B ₂ O ₃ is an optional component and has an effect of reducing devitrification by lowering the expansion coefficient when added in a small amount. However, if the amount is too large, the working point temperature decreases and the working temperature range becomes too narrow, making machining difficult. A preferable range of the content of B ₂ O ₃ is 0 to 5 wt%.

Na ₂ O has the effect of lowering the viscosity and increasing the expansion coefficient when added, and if the amount is too small, the effect cannot be obtained. Moreover, when too much, chemical durability will worsen. A preferable range of the content of Na ₂ O is 3 to 17 wt%.

When K ₂ O is added, the same effect as Na ₂ O can be obtained, but the degree of influence of an increase in expansion coefficient is greater than that of Na ₂ O. Further, by coexisting with Na ₂ O, exert mixed alkali effect, also exhibits the effect of increasing the electrical resistivity. If the amount is too small, the effect cannot be obtained. If the amount is too large, the expansion coefficient becomes too large. A preferable range of the content of K ₂ O is 1 to 12 wt%.

When Li ₂ O is added, the same effect as Na ₂ O or K ₂ O can be obtained, but the increase in expansion coefficient is smaller than that of Na ₂ O. Further, by coexisting with Na ₂ O or K ₂ O, a further mixed alkali effect is exhibited, and an effect of further increasing the electrical resistivity is also exhibited. If the amount is too small, the effect cannot be obtained. If the amount is too large, the glass may be phase-separated. A preferable range of the content of Li ₂ O is 0.5 to 7 wt%.

  MgO and CaO have the effect of improving chemical durability by adding in addition to the above-described effect of suppressing the elution of alkali components. If the amount is too small, the effect cannot be obtained. If the amount is too large, the glass may be devitrified. A preferable range of the MgO content is 1 to 4 wt%, and a preferable range of the CaO content is 1 to 7.3 wt%.

  SrO, BaO, and ZnO are substances that have an effect on improving the electrical resistivity of the glass in addition to the above-described effect of suppressing the elution of alkali components, and also provide electrical insulation. If the content is more than 10 wt%, the glass tends to be devitrified. Preferred ranges are 0 to 8 wt% for SrO, 0 to 10 wt% for BaO, and 0 to 10 wt% for ZnO. Within this range, a more suitable glass for a fluorescent lamp can be obtained.

ZrO is an optional component and has the effect of increasing hardness when added. If too much, the glass may crystallize. A preferable range of the content of ZrO is 0 to 5 wt%.
Fe ₂ O ₃ is a substance mixed as an impurity of various raw materials, but the amount of Fe ₂ O ₃ can be adjusted by refining the raw materials and can absorb ultraviolet rays when added. If the amount is too small, the effect cannot be obtained. If the amount is too large, the glass may be colored. A preferable range of the content of Fe ₂ O ₃ is 0.01 to 0.2 wt%.

Sb ₂ O ₃ is an optional component and has an effect of efficiently clarifying the gas generated from the raw material in the glass melting furnace, but if it is too much, the glass may be colored. A preferable range of the content of Sb ₂ O ₃ is 0 to 1 wt%.

CeO ₂ is an optional component and has an effect of absorbing ultraviolet rays when added, but if it is too much, so-called solarization, which is colored by ultraviolet irradiation, may occur. A preferable range of the CeO ₂ content is 0 to 1 wt%.

<Fluorescent lamp>
FIG. 4 is a partially broken plan view showing an annular fluorescent lamp according to one embodiment of the present invention. As shown in FIG. 4, an annular fluorescent lamp (FCL30ECW / 28) 10 according to an embodiment of the present invention includes an annular bulb 20 and stems 30 and 31 ′ sealed at both ends of the bulb 20. , And a base 40 attached across the both ends.

  The bulb 20 is obtained by processing a glass tube according to the present invention. A protective layer (not shown) and a phosphor layer (not shown) are sequentially laminated on the inner surface of the bulb 20 to supply mercury vapor therein. Amalgam grains 21 and argon gas which is an example of a rare gas are enclosed. Mounted on each stem 30, 30 'is an electrode 31, 31' comprising a filament coil and a pair of lead wires. The base 40 includes a main body 41 in which the end of the valve 20 is accommodated and a plurality of connection pins 42 provided on the main body 41.

<Lighting device>
FIG. 5 is a perspective view showing an illumination apparatus according to an embodiment of the present invention. As shown in FIG. 5, the illuminating device 100 which concerns on this Embodiment is provided with the fluorescent lamp 10 mentioned above as a light source. The fluorescent lamp 1 is accommodated in the apparatus main body 101 and is turned on by a lighting means 102 attached to the apparatus main body 101.

[Method of manufacturing glass tube and lamp]
<Glass tube manufacturing method>
First, a plurality of types of glass raw materials are prepared within the above composition range to obtain a raw material mixture. Next, the raw material mixture is put into a glass melting furnace and melted at 1500 to 1600 ° C. to vitrify to obtain a glassy glass melt. Thereafter, the glass melt is formed into a tubular shape by a tube drawing method such as the Danner method, and cut into a predetermined size to obtain a glass tube.

  The formation of the first film is performed by spraying vapor generated by heating an organic metal on a glass tube being drawn in a draft chamber. For example, the organic metal is heated at 180 ° C. to vaporize 10 g per minute, and the obtained vapor is sprayed on a glass tube at a flow rate of 5 L / min for 1 second to form a first coating. The film thickness of the first coating can be controlled by adjusting the vaporization temperature, the amount of organic metal used, the spraying speed, the spraying time, and the like. The first coating may be formed by a method in which an organic metal dissolved in water or an organic solvent is sprayed, or a method in which the tube body is immersed and applied in the dissolved material.

  As the organic metal used for forming the first film, for example, an organic metal containing tin, titanium, zirconium, or silicon as a metal component is used. Specific examples include tin tetrachloride, titanium tetrachloride, zirconium tetrachloride, silicon tetrachloride, dimethyldichlorotin, dimethyldichlorotitanium, dimethyldichlorozirconium, dimethyldichlorosilicon, acetylacetonetin, acetylacetone titanium, acetylacetonezirconium, and acetylacetonesilicon. Can be mentioned.

  When the hydrophobic lubricant is used, the second coating is formed by, for example, emulsifying the hydrophobic lubricant in water or an organic solvent, and applying the prepared liquid to the glass tube to form a coating. As a coating method, a spraying method by spraying or a method of immersing and applying a tube body is used. Moreover, when using surfactant, it coats using the spraying method by spraying and the method of immersing and apply | coating a pipe | tube main body, for example.

<Lamp manufacturing method>
6A and 6B are diagrams illustrating a method for manufacturing a fluorescent lamp, wherein FIG. 6A is a diagram illustrating a phosphor coating process, FIG. 6B is a diagram illustrating a sintering process, and FIG. 6C is a bulb. It is a figure explaining a sealing process, (d) is a figure explaining a valve | bulb bending process.

  First, in the phosphor coating step, as shown in FIG. 6A, a phosphor suspension 50 of three wavelengths is poured into a glass tube 21 having a protective film formed on the inner surface, and the inner surface of the glass tube 21 is moved. Wet with the phosphor suspension 50. Next, hot air (25 to 30 ° C.) is blown into the glass tube 21 to dry the phosphor suspension 50, and then the atmosphere is controlled to about 550 to 660 ° C. as shown in FIG. 6B. The phosphor layer is formed by baking for about 1 minute in the furnace. Thus, since a glass tube is heat-processed in a sinter process, an alkali component tends to elute.

  Next, in the bulb sealing step, after removing the phosphor layers in the vicinity of both ends of the glass tube 21, as shown in FIG. 6 (c), stems 30 and 30 'are inserted into the both ends and sealed. To do. In the subsequent bulb bending step, the straight glass tube 21 is bent into an annular shape in a furnace whose atmosphere is controlled at about 700 to 900 ° C., as shown in FIG. As described above, since the glass tube is heat-treated in the bulb bending process, the alkali component is likely to be eluted.

  Thereafter, in the exhaust process, the impure gas is exhausted from the inside of the valve 20 through the unsealed exhaust pipe 32, and the inside of the valve 20 is brought to a state close to a vacuum, and then argon gas is introduced. Further, in the amalgam sealing step, amalgam particles 21 are introduced into the valve from the exhaust pipe 32.

[Evaluation methods]
The glass tube for a fluorescent lamp was evaluated by the following method.
<Film thickness>
The film thickness of the coating was measured using a hot end coating meter (HOT END COATING MEASUREMENT SYSTEM: HECM-S) manufactured by American Glass Research.

  FIG. 7 is a diagram for explaining a method of measuring the film thickness. As shown in FIG. 7 (a), a glass tube cut into 20cm is prepared as a sample, and as shown in FIG. The film thickness was measured at 4 points with a uniform interval in the direction (with an interval of about 90 ° rotation angle) (12 points in total), and the average of these 12 points was taken as the film thickness. The incident angle of light at each point was 45 °.

  In the hot-end coating meter, the film thickness is expressed by ctu (coating thickness units), which is a unique unit, and 1 ctu is 0.2 to 0.3 nm in SI units. In this application, it is converted as 1 ctu = 0.25 nm.

<Glass strength>
First, in the experiment, a straight glass tube having an outer diameter of 4 mm and an inner diameter of 3 mm and having a first coating and a second coating formed on the outer peripheral surface was used. The first coating has a thickness of 100 nm composed of tin oxide by heating dimethyldichlorotin powder at 120 ° C. for 1 minute and blowing the generated vapor onto the glass tube being drawn in the draft chamber. Formed. The 2nd film formed the thing of the film thickness of 30 nm which consists of various materials as shown in FIG.1 and FIG.2 by spraying with a spray with respect to the glass tube in tube drawing.

  Next, the glass tube on which the coating has been formed is placed in a quartz tube having an inner diameter of 20 mm, and the quartz tube is rotated at a rotation speed of 20 rpm for 5 minutes in an environment of 500 ° C., and the glass tube and the quartz tube are rubbed together. Injured the surface of the glass tube.

  Then, the bending strength of the glass tube after an injury was measured using Autograph AG-IS (made by Shimadzu Corporation). The bending strength was measured by fixing the glass tube with a left and right span of 40 mm, applying a load at a load rate of 1 mm / min to the center of the glass tube, and obtaining a value when the glass tube was broken.

  When the bending strength is reduced by 30% or more due to scratching, the glass strength is evaluated as “x” as insufficient, and when the bending strength is reduced by less than 30%, the glass strength is assumed to be sufficient. It was evaluated as “Δ” (when the bending strength was reduced by 15% or more and less than 30%) or “◯” (when the bending strength was reduced by 0% or more and less than 15%). The reason why the glass strength is insufficient when the bending strength is reduced by 30% or more is that when a fluorescent lamp is manufactured using a glass tube whose bending strength is reduced by 30% or more, the yield in the process is increased. It is because it falls remarkably.

<White turbidity>
The white turbidity was evaluated by visual observation. When white turbidity was not visually observed, “◯” was evaluated, and when white turbidity was visually observed, “×” was evaluated.

<Abrasion resistance>
The scratch resistance was evaluated according to the following procedure. First, two glass tubes cut into 10 cm were brought into contact at an angle of 90 ° and rubbed 20 times. Thereafter, the rubbed portions were magnified 4 times with an optical microscope and observed. As a result, “X” was evaluated for those in which formation of scratches was confirmed, and “O” was evaluated for those in which scratches were not confirmed.

<Softening point temperature and working point temperature>
In order to measure the softening point temperature and working point temperature of the glass, a sample was prepared by the following procedure. First, the raw material mixture obtained by preparing the glass raw material is transferred to a platinum crucible, and the platinum crucible is melted in an electric furnace at 1500 ° C. for 3 hours to be vitrified. After melting, it is poured into a mold and gradually cooled (annealed) over 12 hours so that sufficient strain can be removed. The molded glass lump was molded into a sample shape suitable for each measurement described below using a cutting machine or the like, and each measurement was performed.

The softening point temperature is a temperature at which the viscosity of the glass becomes 10 ^7.65 dPa · s, and when the temperature becomes equal to or higher than the temperature, the glass obtains fluidity. The softening point temperature is preferably in the range of 650 ° C. to 720 ° C. and more preferably in the range of 670 to 700 ° C. for fluorescent lamps. When the softening point temperature is lower than 650 ° C., the bulb is deformed by the heat when heated in order to volatilize the binder of the phosphor suspension in the phosphor baking step. On the other hand, if the softening point temperature is higher than 720 ° C., the glass tube must be heated at the time of sealing, and the combustion capacity of the melting furnace must be increased.

The working point temperature is the temperature at which the viscosity of the glass is 10 ⁴ dPa · s. Below this temperature, the glass is processed. The working point temperature is preferably in the range of 960 ° C. to 1050 ° C. and more preferably in the range of 960 to 1000 ° C. for fluorescent lamps. When the working temperature is lower than 1000 ° C., the working temperature range becomes narrow, so that workability is poor. On the other hand, when the working point temperature is higher than 1050 ° C., the temperature at which the glass melts becomes too high, so that the workability is deteriorated and the cost of the melting step is also increased.

<Alkali elution amount>
As a method for measuring the amount of alkali elution, a test method for a glass instrument for chemical analysis based on JIS (Japanese Industrial Standard JIS R 3502) is generally used. This method will be briefly explained. First, a glass sample is pulverized into a powder (particle size: 250 to 420 μm) using a mortar or the like to obtain a crushed glass, and then the crushed glass is washed with ethyl alcohol. Then, the glass fine powder is removed from the pulverized glass, and the washed glass pulverized product is heated in a boiling water bath for 60 minutes to elute alkali components from the pulverized glass to obtain an alkali eluate. Then, the alkali eluate is neutralized and titrated with sulfuric acid, and the alkali elution amount is converted from the obtained titration value.

  In such a test method based on JIS, if washing with ethyl alcohol is insufficient, glass fine powder remains in the crushed glass, and therefore the total surface area of the glass in distilled water is greatly increased due to the presence of the glass fine powder. There is a problem that the amount of alkali elution cannot be measured accurately. In addition, complicated operations such as pulverizing the glass sample, removing the fine glass powder by washing, and neutralizing titration are required. Therefore, a more accurate and simple method for measuring the amount of alkali elution is desired.

  Accordingly, the inventors newly established a method for measuring the amount of alkali elution that is more accurate and simpler than the test method based on JIS. In the measurement method according to the present invention, a block-shaped glass sample is immersed in distilled water to elute alkali components from the glass sample into distilled water, and the conductivity of the obtained alkaline eluate is measured. The amount of alkali elution is converted.

FIG. 8 is a diagram for explaining a method for measuring an alkali elution amount according to the present invention. A specific procedure of the measurement method according to the present invention will be described with reference to FIG.
First, a glass sample is cut into a block shape, and left for 45 to 50 hours in a constant temperature and humidity chamber maintained at a temperature of 75 to 85 ° C. and a humidity of 85 to 95%, and then subjected to moisture treatment. In order to increase the measurement accuracy, it is more preferable that the temperature, humidity, and standing time in the impregnation treatment are 80 ° C., 90%, and 48 hours, which are values near the center of each range.

  Next, as shown in FIG. 8, 100 ml of 70 to 80 ° C. distilled water 2 is stored in the water tank 1, and the glass sample 3 that has been subjected to the moisture treatment is immersed in the distilled water 2 for 1 hour. In the measuring method according to the present invention, since alkaline components are eluted in distilled water 2 having a relatively low temperature of 70 to 80 ° C., a test method based on JIS for forcibly eluting alkaline components in boiling distilled water is used. In addition, it is possible to measure the alkali elution amount more in line with the actual usage form of glass.

Glass sample 3, the sum of the surface area within the range defined by 4500～5500Mm ^2, is preferably adjusted to about 5000 mm ² immersion. For example, eight glass samples 3 cut into a rectangular parallelepiped shape of about 15 × 15 × 2.5 mm are immersed.

  Thereafter, the glass sample 3 is removed from the distilled water 2 to obtain an alkaline eluate. And the said alkali elution liquid is stabilized at 25 degreeC, and conductivity is measured using the commercially available handy type sensor type liquid immersion type conductivity measuring machine 4 (brand name: Twincond B-173).

  FIG. 9 is a graph showing the correlation between the alkali elution amount measured by the test method based on JIS and the conductivity measured by the test method according to the present invention. The alkali elution amount and the electrical conductivity are in a correlation as shown in FIG. Although it is considered that glass having an alkali elution amount of 270 μg / g or less is suitable for a bulb of a fluorescent lamp, as can be seen from FIG. 9, the conductivity corresponding to an alkali elution amount of 270 μg / g is 57 μS / g. cm. Therefore, it can be said that a glass having a conductivity of 57 μS / cm or less is suitable as a glass for a bulb.

  That is, the electrical conductivity is a numerical value indirectly indicating the alkali elution amount of the glass, and in order to be a glass suitable for a fluorescent lamp, it can be said that it is preferably 57 μS / cm or less at 25 ° C. When the conductivity is higher than 57 μ / cm, various problems due to the formation of amalgam become remarkable.

  Since the said measuring method uses a block-shaped glass sample, it is easy to control the sum total of the surface area of the glass immersed in distilled water. Therefore, the alkali elution amount can be measured with higher accuracy than the test method based on JIS. In addition, since the measurement method according to the present invention measures the alkali elution amount based on the conductivity, the measurement accuracy does not deteriorate even if the alkali elution amount increases.

  In addition, since the above-described measurement method immerses the cut block-shaped glass sample in distilled water, it is not necessary to pulverize the glass sample into powder or wash the crushed glass. In addition, the measurement of the conductivity of the alkaline eluate can be performed by a simple operation of just immersing the electrode of the conductivity measuring device 4 in the alkaline eluate, and no complicated neutralization titration work is required. Therefore, the operation is simpler than the measurement method based on JIS.

<Devitrification>
When the glass was melted and vitrified, it was visually confirmed whether or not crystals were generated on the glass and devitrified. Evaluation was made that “O” was not devitrified and “x” was devitrified.

<Ratio of tetragonal crystals>
First, in the experiment, a straight glass tube having an outer diameter of 4 mm and an inner diameter of 3 mm and having a first film formed on the outer peripheral surface was used. The first coating was formed by heating the powder of dimethyldichlorotin at 120 ° C. for 1 minute and blowing the generated vapor onto the glass tube being drawn in the draft chamber to a film thickness of 100 nm.

Next, the first film as it was formed on the glass tube was observed with an X-ray diffractometer (RINT2000, manufactured by Rigaku Corporation), and the crystal structure of the oxide constituting the first film was confirmed. The measurement was performed under the conditions of a scan speed of 6 ° / min and a measurement range of 0 ° to 90 °, and the ratio of SnO and SnO ₂ crystals was evaluated. SnO is mainly tetragonal as a crystal structure, but has a cubic crystal structure as a partial transformation, whereas SnO ₂ has only a tetragonal crystal structure. Therefore, it is preferable as the first coat of glass in the state of SnO _2. Thereby, the concealability of the first coating on the glass surface is improved, and a greater effect can be obtained. In particular, the ratio SnO ₂ / SnO is preferably 1 or more.

[Modification]
As described above, the fluorescent lamp and the fluorescent lamp glass tube according to the present invention have been specifically described based on the embodiments. However, the fluorescent lamp glass tube, the fluorescent lamp, and the lighting device according to the present invention are described above. It is not limited to.

  The glass tube for a fluorescent lamp according to the present invention is suitable not only for producing a bulb but also for producing a flare, an exhaust tube, or the like that is heat-treated at the time of processing and is required to be thin. The glass constituting the tube body may be soft glass or hard glass, but the configuration of the present invention is particularly effective in the case of soft glass having low glass strength.

  The fluorescent lamp according to the present invention is not limited to the above embodiment, but a straight tube fluorescent lamp, an annular fluorescent lamp, a cold cathode fluorescent lamp, a double annular fluorescent lamp, a square fluorescent lamp, and a double square fluorescent lamp. Widely used for fluorescent lamps such as lamps and twin fluorescent lamps.

  The lighting device according to the present invention is not limited to the above embodiment. For example, it can be widely used in lighting devices such as indoor lighting devices, outdoor lighting devices, desk lighting, portable lighting, display light sources, liquid crystal screen backlights, and image reading lighting.

  The glass tube for a fluorescent lamp according to the present invention can be widely used for lighting applications.

DESCRIPTION OF SYMBOLS 10 Lamp 20 Bulb 21 Fluorescent lamp glass tube 22 Tube body 23 1st film 24 2nd film 100 Illumination device

Claims (9)

A tube body composed of glass containing 60-75 wt% silicon oxide and 5-18 wt% alkaline earth metal oxide;
A first coating formed on at least an outer peripheral surface of the tube main body and composed of at least one oxide selected from tin oxide, titanium oxide, zirconium oxide and silicon oxide;
A glass tube for a fluorescent lamp, comprising: a second coating laminated on the first coating and made of a hydrophobic lubricant or a surfactant having an HLB of 13 or less.   The glass tube for a fluorescent lamp according to claim 1, wherein the hydrophobic lubricant is an olefin resin or a high melting point wax.   The glass tube for a fluorescent lamp according to claim 1 or 2, wherein the alkaline earth metal oxide is at least one oxide selected from magnesium oxide and calcium oxide.   The fluorescent lamp according to claim 1 or 2, wherein the alkaline earth metal oxide is magnesium oxide and calcium oxide, and a molar ratio of the calcium oxide to the magnesium oxide is 0.5 to 3. Glass tube.   2. The glass tube for a fluorescent lamp according to claim 1, wherein the glass constituting the tube main body contains a total of 8 to 20 wt% of alkali metal oxides.   2. The glass tube for a fluorescent lamp according to claim 1, wherein the oxide constituting the first coating has a tetragonal crystal structure of 50 wt% or more. The tube body has a wall thickness t [mm] and an outer diameter φ [mm].
t ≦ 0.7 or t / φ ≦ 0.42
The glass tube for a fluorescent lamp according to claim 1, wherein the relationship is satisfied.   A fluorescent lamp comprising a bulb produced using the fluorescent lamp glass tube according to claim 1.   An illumination device comprising the fluorescent lamp according to claim 8.

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