JP2007182366A - Outer sleeve container for external electrode fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an outer sleeve container for external electrode lamps which satisfies all the characteristics required for an outer sleeve container for an external electrode lamp, specifically the thermal expansion coefficient α, the liquid-phase viscosity log η, the dielectric constant ε, the dielectric loss tangent tan δ, and the volume resistivity log ρ. <P>SOLUTION: The outer sleeve container is used for producing an external electrode fluorescent lamp having a structure, wherein an electrode is arranged outside, and is composed of a glass containing, in mass%, 45-60% of SiO<SB>2</SB>, 0-10% of B<SB>2</SB>O<SB>3</SB>, 0-10% of Al<SB>2</SB>O<SB>3</SB>, 0-10% of MgO, 0-10% of CaO, 0-9% of SrO, 5-25% of BaO, 0-13% of ZnO, 0-5% of TiO<SB>2</SB>, 0-3% of CeO<SB>2</SB>, 20-40% of ΣRO(=MgO+CaO+SrO+BaO+ZnO) and 5-9.8% of ΣR<SB>2</SB>O(=Li<SB>2</SB>O+Na<SB>2</SB>O+K<SB>2</SB>O). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a jacket for an external electrode fluorescent lamp.

  Since liquid crystal display elements do not self-emit, a dedicated lighting device (hereinafter referred to as a backlight unit) may be used when used in applications such as notebook computers, TV monitors, personal computer (PC) monitors, and in-vehicle instruments. Widely done.

  A fluorescent lamp serving as a light source of a conventionally used backlight unit uses a compact and long-life cold cathode tube. The light emission principle of the cold cathode tube is the same as that of a general fluorescent lamp for illumination. That is, electric power is supplied to the internal electrodes via a jumet wire, Kovar metal, tungsten metal, etc. enclosed in a glass jacket, and a discharge is caused between the electrodes. The discharge between the electrodes excites mercury (Hg) and xenon (Xe) sealed in the outer container, and radiates ultraviolet rays. The phosphor coated on the inner wall surface of the outer container emits visible light by the emitted ultraviolet light. In order to control the amount of current during emission of the fluorescent lamp, the cold cathode tube unit requires an inverter for increasing the voltage for each lamp and a capacitor for controlling the current.

  In recent years, liquid crystal display devices have become larger, and accordingly, a plurality of cold cathode tubes have been used in the backlight unit in order to ensure sufficient brightness. For example, a TV monitor mainly uses a backlight unit that emits light uniformly by arranging a plurality of fluorescent lamps on the back side of a liquid crystal display device at intervals of about 1 to 5 cm and emitting light through a diffusion plate. In such a display device, power supplies are installed for the number of lamps, so that the volume occupied by the power supply in the display device increases. As a result, not only is it difficult to reduce the thickness of the display device, but the price also increases. Therefore, it is expected to integrate the power supply of the unit into one, but it was impossible in the past because the capacitor cannot be omitted.

  In the conventional cold cathode lamp, the metal electrode reacts with Hg during lighting to form an alloy and consumes Hg. Since Hg is a component that contributes to light emission, the cold-cathode lamp gradually becomes dark and eventually cannot withstand use. Thus, there is a limit to the life of a cold cathode tube. Its lifetime is not long enough for TV monitors.

  Under such circumstances, an external electrode fluorescent lamp (EEFL) in which there is no internal electrode that tends to affect the life and electrodes are arranged in the vicinity of both ends of the outer surface of the lamp mantle tube has been studied. (For example, patent document 1, nonpatent document 1) Moreover, the planar external electrode lamp which has several discharge space is also proposed (for example, patent document 2, 3). The power supply method of the external electrode fluorescent lamp does not directly emit electrons from the electrode as in the cold cathode lamp, but functions the glass portion of the glass envelope as a dielectric, and the electrons from the inner surface of the tube due to its dielectric characteristics. Is to be released. That is, an alternative mechanism for the condenser is constructed using the lamp envelope. As a result, no capacitor is required and power supply can be integrated. The basic light emission principle is to generate ultraviolet rays by Hg or Xe to illuminate the phosphor as in the conventional fluorescent lamp.

  The flat external electrode lamp has a structure having electrodes on the outer surface of the lamp opposite to the surface from which light is extracted. For example, as shown in FIG. 1, the thickness of the glass plate of the back plate 1 is a dielectric, a pair of strip electrodes 3 (external electrodes) is one electrode, and Hg vapor or Xe inside the lamp is the other electrode. Function as. This structure is similar to a capacitor. Light passes through the front plate 2 and is extracted.

  The outer container is composed of a back plate 1 and a front plate 2. The back plate 1 is manufactured by a generally known glass plate manufacturing method such as a float method, an overflow method, or a slit down method. The front plate 2 is manufactured by a generally known glass plate manufacturing method such as a float method, an overflow method, or a slit down method, and then manufactured by heat softening press molding using a predetermined mold. Alternatively, it is produced by pouring molten glass into a mold and directly press-molding with a predetermined mold. In these glass plate production methods, the thermal expansion coefficient α is an important factor. That is, if the thermal expansion coefficient α is too large, the glass plate is damaged by a thermal shock during the cooling process during the manufacturing process, making it difficult to continuously manufacture the glass plate. Also, in the press molding process, the frequency of breakage of the molded glass due to thermal shock during the cooling process after pressing increases. Furthermore, in recent years, with the increase in the size of liquid crystal display devices, a larger outer casing is required, and it is necessary to manufacture a larger glass plate, and it is considered that the frequency of breakage due to thermal shock is further increased.

  The tube-type external electrode lamp has a structure having electrodes on the outer peripheral surface of the outer casing. As shown in FIG. 2, the glass thickness of the glass tube (outer tube) 6 functions as a dielectric, the external electrode 3 functions as one electrode, and the Hg vapor or Xe inside the lamp functions as the other electrode 3. This structure is similar to a capacitor. When a plurality of lamps L1 and L2 are connected to one power source 10, the voltage is equal for each lamp.

  The outer container is made of a glass tube 6. The glass tube 6 is manufactured by a generally known glass tube manufacturing method such as the Danner method, the down draw method, or the up draw method. The thermal expansion coefficient α is an important factor also in the glass tube manufacturing process. If the thermal expansion coefficient α is too large, the glass tube is damaged by a thermal shock during the cooling process during the manufacturing process, making it difficult to continuously manufacture the glass tube. In addition, it is considered that the frequency of breakage increases in the cooling process after heat-softening and sealing the glass tube in the fluorescent lamp manufacturing process, or in the cooling process after heat-softening and bending the glass tube.

For this reason, it is desirable that the thermal expansion coefficient α of the glass constituting the outer casing is not too high in any type of outer casing, specifically 90 × 10 ⁻⁷ / ° C. or less. The external electrode fluorescent lamp does not need to seal electrodes such as jumet wire, kovar metal, tungsten metal and glass. For this reason, the coefficient of thermal expansion α of the glass used for the outer container is arbitrary, but the lower the coefficient of thermal expansion α, the better.

  In molding from molten glass into a glass plate or glass tube, it is important that devitrification due to crystal precipitation does not occur due to molding viscosity. The viscosity at which crystals are precipitated is indicated by the liquid phase viscosity log η, and it can be said that molding is possible when the liquid phase viscosity log η is greater than the molding viscosity. In the formation of a normal glass plate or glass tube, the liquidus viscosity log η is desirably 5.2 or more.

  In the external electrode fluorescent lamp, power is supplied to the lamp by driving the above-described condenser mechanism with an AC power supply. The brightness of the lamp is determined by the amount of power. The amount of electric power (charge Q) of the capacitor is obtained from the capacitance C and the voltage V (below).

Q = C × V − Formula 1
[Q: charge C: capacitance V: terminal voltage]
As is clear from Equation 1, it can be said that the capacitance C determines the charge Q. The capacitance C is the product of the reciprocal of the dielectric constant ε, the area S, and the thickness d. (Following formula)
C = ε × S × (1 / d) − Equation 2
[C: Capacitance ε: Dielectric permittivity S: Electrode area d: Dielectric thickness]
From Equation 1 and Equation 2, Equation 3 can be derived.

Q = ε × S × (1 / d) × V − Equation 3
As apparent from Equation 3, if the terminal voltage V, the electrode area D, and the dielectric thickness d are constant, the charge Q increases as the dielectric constant ε increases, and the lamp efficiency of the external electrode fluorescent lamp increases. Further, if the charge Q is constant, the higher the dielectric constant ε, the smaller the terminal voltage V, and the power can be saved. Since the outer wall of the external electrode fluorescent lamp has a glass thickness that acts as a dielectric, the dielectric constant ε of the glass is high. Specifically, the dielectric constant ε at 1 MHz and room temperature is 6.5 or more. desired.

  Further, when the dielectric loss tangent tan δ is large, the dielectric loss increases. Since the dielectric loss is converted into thermal energy, if the dielectric loss is large, the glass itself starts to generate heat. If the heat generation continues, there is a risk that the glass will be softened and a hole may be formed in the electrode portion of the lamp. For this reason, it is desirable that the dielectric loss tangent is small, specifically, the dielectric loss tangent tan δ at 1 MHz and room temperature is 0.003 or less.

  Furthermore, since the fluorescent lamp is used at a frequency of 40 KHz to 100 KHz, the dielectric characteristics in this frequency region are also important. The dielectric loss tangent tan δ tends to decrease as the frequency increases. That is, the dielectric loss tangent tan δ at 40 KHz is higher than that at 100 KHz. Therefore, the dielectric property of the glass for an outer container can be defined by a value of 40 KHz. It is desirable that the dielectric constant ε at 40 KHz is 7.0 or more, and the dielectric loss tangent tan δ is 0.01 or less at 150 ° C., 0.02 or less at 250 ° C., and 0.1 or less at 350 ° C. 150 ° C. corresponds to the normal operating temperature of the lamp. 250 ° C. corresponds to a temperature that can occur inside the lamp. Furthermore, 350 ° C. is a temperature that should be taken into consideration for safety. Among these temperatures, the maximum temperature conceivable for a fluorescent lamp is about 250 ° C., so the value at this temperature is most important.

Further, the external electrode fluorescent lamp has a high terminal voltage. For this reason, if the volume resistivity log ρ of the glass is low, current flows through the glass, lamp efficiency is lowered, and there is a risk of deformation of the outer casing or ignition of peripheral members due to Joule heat. Therefore, it is desired that the volume resistivity logρ is high, specifically 9.5 or more.
JP2002-8408 Special table 2002-508574 JP 2000-156199 A Journal of the Illuminating Society of Japan vol. 87 no. 1 2003 p18

Conventionally, a commercially available borosilicate glass tube or soda glass tube used as an outer tube of a cold cathode lamp has been diverted as an outer electrode lamp outer tube. This type of borosilicate glass has a thermal expansion coefficient α of about 30 to 60 × 10 ⁻⁷ / ° C., which can be sealed with Kovar metal or tungsten metal used for an electrode of a cold cathode lamp. The soda glass has a thermal expansion coefficient α of about 90 to 100 × 10 ⁻⁷ / ° C., which can be sealed with a jumet metal used as an electrode of a cold cathode lamp.

  However, the external electrode lamp manufactured using the outer tube of the cold cathode lamp cannot obtain a high-performance lamp because the outer casing glass does not have appropriate dielectric properties. In other words, when a borosilicate glass tube is used, there is a problem that the lamp efficiency is poor because the dielectric constant is low. When a soda glass tube is used, the lamp efficiency is high, but the dielectric loss is large. Therefore, there is a problem that the electrode portion is perforated due to the heat generated by the glass.

  The object of the present invention is to provide external characteristics that satisfy all of the characteristics required for an outer electrode lamp envelope, specifically, thermal expansion coefficient α, liquidus viscosity logη, dielectric constant ε, dielectric loss tangent tanδ, and volume resistivity logρ. It is to provide an outer casing for an electrode lamp.

  As a result of various studies, the present inventor has found that the above object can be achieved by selecting a glass composition within a specific range, and proposes the present invention.

That is, the outer electrode lamp envelope of the present invention is an outer vessel used for manufacturing an external electrode fluorescent lamp having a structure in which an electrode is provided on the outer surface, and is SiO ₂ 45-60% by mass, B ₂ O ₃ 0-10%, Al ₂ O ₃ 0-10%, MgO 0-10%, CaO 0-10%, SrO 0-9%, BaO 5-25%, ZnO 0-13%, TiO ₂ 0 ˜5%, CeO ₂ 0 to 3%, ΣRO (= MgO + CaO + SrO + BaO + ZnO) 20 to 40%, ΣR ₂ O (= Li ₂ O + Na ₂ O + K ₂ O) 5 to 9.8% .

  In the following, “%” means “mass%” unless otherwise specified.

The outer electrode lamp outer casing of the present invention has various characteristics required for an outer casing (specifically, thermal expansion coefficient α at 30 to 380 ° C. is 70 to 90 × 10 ⁻⁷ / ° C., liquid phase viscosity log η is 5). .2 or higher, 1 MHz, room temperature dielectric constant ε is 6.5 or higher, dielectric loss tangent tan δ is 0.003 or lower, volume resistivity logρ at 250 ° C. is 9.5 or higher, and dielectric constant ε at 40 KHz and 150 ° C. is 7 or higher. The dielectric loss tangent tan δ is 0.01 or less, the dielectric constant ε at 40 KHz and 250 ° C. is 7 or more, the dielectric loss tangent tan δ is 0.02 or less, the dielectric constant ε at 40 KHz and 350 ° C. is 7 or more, and the dielectric loss tangent tan δ is 0.1. Since it is made of glass capable of satisfying all of the following, the glass is less likely to be devitrified and broken in the manufacturing process of the outer container. Moreover, the external electrode lamp manufactured using this outer casing has a high lamp efficiency, and it is difficult to cause a problem that the electrode portion is perforated due to glass heat generation during lighting.

  The envelope of the present invention is an envelope used for manufacturing an external electrode fluorescent lamp having a structure in which an electrode is provided on the outer surface. The container shape can be a shape suitable for the lamp shape.

  For example, in the case of a tube lamp, the outer container has a tube shape. Here, the tube shape means that the cross section is not limited to a perfect circle but a columnar body having various cross sectional shapes such as an ellipse.

  In the case of a flat lamp, the outer casing has a substantially box shape so as to form one or a plurality of discharge spaces. The outer container is preferably composed of a plurality of members due to manufacturing restrictions. For example, the back surface portion and the front surface portion can be composed of separate members, that is, a front plate and a back plate. When a plurality of discharge spaces are formed, for example, a plurality of concave portions or convex portions may be provided on the front plate and / or the back plate.

The outer container of the present invention is, by mass%, SiO ₂ 45-60%, B ₂ O ₃ 0-10%, Al ₂ O ₃ 0-10%, MgO 0-10%, CaO 0-10%, SrO 0. ~9%, BaO 5~25%, ZnO 0~13%, TiO 2 0~5%, CeO 2 0~3%, ΣRO (= MgO + CaO + SrO + BaO + ZnO) 20~40%, ΣR 2 O (= Li 2 O + Na 2 O + K ₂ O) Made of glass containing 5 to 9.8%. The reason for limiting the glass composition range as described above will be described below.

SiO ₂ is a main component necessary for constituting the skeleton of the glass, and the mechanical strength of the glass improves as the content increases. On the other hand, since there is a tendency to increase the viscosity, it is difficult to melt or mold the glass if it is too much. Its content is 45% or more, preferably 48% or more. Moreover, it is 60% or less, Preferably it is 58% or less. If SiO ₂ is 45% or more, a usable mechanical strength can be secured. If it is 48% or more, the mechanical strength which can endure the continuous production in a glass plate and a glass tube manufacturing process can be obtained. Further, if SiO ₂ is 60% or less, it does not take a long time to melt the glass, so that the productivity is not hindered. If it is 58% or less, thermal processing in the press molding process of the glass plate and the manufacturing process of the fluorescent lamp can be performed smoothly.

B ₂ O ₃ is a component constituting the skeleton of the glass, but is an effective component for improving the melting property of the glass and lowering the viscosity because the melting temperature is low. On the other hand, when there is too much content, glass will phase-separate and glass shaping will become difficult. Its content is 10% or less, preferably 8% or less, more preferably 7.5% or less. If the content of B ₂ O ₃ is 10% or less, production can be performed without phase separation in the manufacturing process of the glass plate and the glass tube, and if it is 8% or less, continuous stable production can be performed for a long time. it can.

Al ₂ O ₃ is a component constituting the skeleton of the glass, and has the effect of improving the stability of the glass and suppressing the phase separation of the glass. On the other hand, since there exists a tendency to raise a viscosity, when it is too much, it will become difficult to shape | mold glass. Its content is 10% or less, preferably 8% or less, more preferably 7% or less. If Al ₂ O ₃ is 10% or less, the viscosity of the glass melt will not be too high, and melting of the glass and forming of the glass plate and glass tube will be facilitated. If it is 7% or less, it is possible to smoothly perform the heat processing in the press molding process of the glass plate and the manufacturing process of the fluorescent lamp.

  MgO and CaO are components that fill the gaps in the glass skeleton. There is an effect of improving the melting property of the glass without greatly increasing the thermal expansion coefficient α of the glass, and an effect of improving the dielectric properties. On the other hand, in order to strengthen the crystal tendency, it is a component that makes glass easily devitrified. Moreover, when there is too much content, the thermal expansion coefficient (alpha) will be enlarged.

  The contents of MgO and CaO are each 10% or less, preferably 8% or less. When the content of MgO or CaO is 10% or less, devitrification is less likely to occur in the glass plate and glass tube manufacturing process, and production at an industrial level is possible. Further, since the thermal expansion coefficient α does not become too large, the frequency of breakage due to thermal shock is reduced. When the content of MgO or CaO is 8% or less, continuous stable production can be performed over a longer period. Further, the increase in the thermal expansion coefficient α is further suppressed, and the frequency of breakage due to thermal shock is further reduced.

  SrO and BaO are components that fill the gaps in the glass skeleton. There is an effect of improving the melting property of the glass without greatly increasing the thermal expansion coefficient α of the glass, and the effect of improving the dielectric properties. In particular, BaO has a great effect of improving the dielectric characteristics. On the other hand, it is a component that precipitates crystals and makes glass easily devitrified. Moreover, when there is too much content, the thermal expansion coefficient (alpha) will be enlarged.

  The SrO content is 9% or less, preferably 8% or less. When the content of SrO is 9% or less, devitrification in the manufacturing process of the glass plate and the glass tube hardly occurs, and production at an industrial level is possible. Further, since the thermal expansion coefficient α does not become too large, the frequency of breakage due to thermal shock is also reduced. When it is 8% or less, devitrification is not observed, and continuous stable production can be performed over a long period of time. Further, the increase in the thermal expansion coefficient α is further suppressed, and the frequency of breakage due to thermal shock is further reduced. SrO is not an essential component, but it is preferably 0.5% or more, particularly preferably 1% or more.

  The content of BaO is 5% or more, preferably 7.5% or more. Moreover, it is 25% or less, Preferably it is 23% or less, More preferably, it is 22.5% or less. When the content of BaO is 5% or more, an effect of increasing the dielectric constant ε and decreasing the dielectric loss tangent tan δ can be obtained. When it is 7.5% or more, the effect of increasing the dielectric constant ε and decreasing the dielectric loss tangent tan δ is remarkably improved. When the content of BaO is 25% or less, devitrification in the manufacturing process of the glass plate and the glass tube is suppressed, and production at an industrial level becomes possible. Further, since the thermal expansion coefficient α does not become too large, the frequency of breakage due to thermal shock is also reduced. If it is 23% or less, continuous stable production can be performed over a long period of time. Further, the increase in the thermal expansion coefficient α is further suppressed, and the frequency of breakage due to thermal shock is further reduced.

ZnO is a component that fills the gaps in the glass skeleton and is a component that suppresses precipitation of crystals of alkaline earth metal oxides (MgO, CaO, SrO, BaO) and SiO ₂ . It is also a component that is effective in improving dielectric characteristics. On the other hand, when the content of ZnO is too large, crystals containing ZnO are likely to be precipitated, and thus the tendency of glass to devitrify is increased. The content of ZnO is 13% or less, preferably 12% or less. When the content of ZnO is 13% or less, devitrification in the manufacturing process of the glass plate and the glass tube is suppressed, and production can be performed at an industrial level. If it is 12% or less, continuous stable production can be performed over a long period of time. Although ZnO is not an essential component, it is preferable to contain 0.5% or more, particularly 1% or more.

  By ΣRO (total amount of MgO, CaO, SrO, BaO and ZnO), the dielectric properties of the glass can be roughly predicted. That is, as the total amount increases, the dielectric constant ε increases and the dielectric loss tangent tan δ decreases, so that the dielectric characteristics are improved. On the other hand, if the total amount is too large, crystals are likely to precipitate. ΣRO is 20% or more, preferably 25% or more. When ΣRO is 20% or more, it is possible to satisfy the dielectric characteristics required for the outer electrode lamp envelope. Since a sufficiently high dielectric constant can be obtained when it is 25% or more, less power can be applied to the lamp terminal and power can be saved. On the other hand, when ΣRO is 40% or less, devitrification in the manufacturing process of the glass plate and the glass tube can be suppressed, and production can be performed at an industrial level. If it is 38% or less, continuous stable production can be performed over a long period of time.

Alkali metal oxides such as Li ₂ O, Na ₂ O, and K ₂ O are components that fill the gaps in the glass skeleton. It works as a fusing material that makes it easy to melt glass raw materials, and has the effect of facilitating glass melting. It is also a component that tends to improve the dielectric constant ε. On the other hand, when the content increases, the dielectric loss tangent tan δ increases, the volume electric resistance log ρ decreases, and the thermal expansion coefficient α increases. For this reason, the total amount Li ₂ O + Na ₂ O + K ₂ O (= ΣR ₂ O) of these components is 5% or more and 9.8% or less. When ΣR ₂ O is 5% or more, there is no problem in melting the raw material by melting the glass, the production is stable, and the tendency to improve the dielectric constant ε is increased. Further, if it is 9.8% or less, the thermal expansion coefficient α does not become too large, and the dielectric loss tangent tan δ and the volume resistivity logρ do not become too large.

In order to suppress the increase in dielectric loss tangent tan δ and volume resistivity log ρ without reducing the alkali content, the alkali mixing effect may be used. For that purpose, the content of each component is Li ₂ O 0-5%, preferably 0-3%, Na ₂ O 0.1-8%, preferably 0.3-5%, K ₂ O 0.5 It is preferable to adjust to the range of -8%, particularly 1-7%.

Further, among the alkali metal oxides, in particular, when the contents of Li ₂ O and Na ₂ O become too large, the volume resistivity logρ increases. Therefore, it is desirable to adjust Li ₂ O / ΣR ₂ O to 0.4 or less and Na ₂ O / ΣR ₂ O to 0.6 or less in order to obtain an alkali mixing effect more accurately. When these ratios are in the above range, the effect of suppressing the increase in volume resistivity ρ is large and preferable.

Further, the dielectric constant ε of the glass can be predicted from (ΣRO + ΣR ₂ O) / (SiO ₂ + B ₂ O ₃ + Al ₂ O ₃ ). That is, the larger the ratio, the higher the dielectric constant. In order to improve the dielectric constant ε of glass, alkali metal ions (Li ion, Na ion, K ion, etc.), alkaline earth metal ions (Mg ion, Ca ion, Sr ion, Ba ion, etc.) are formed in the gaps of the glass skeleton. Alternatively, it is effective to densely fill with Zn ions or the like. The ratio of (ΣRO + ΣR ₂ O) / (SiO ₂ + B ₂ O ₃ + Al ₂ O ₃ ) is preferably 0.55 or more. When this ratio is smaller than 0.55, the effect of improving the dielectric constant ε is small. However, if it exceeds 0.85, the thermal expansion coefficient α becomes too large, which is not preferable.

Note that an element having a larger atomic number has a greater effect of improving the dielectric constant ε. That is, in R ₂ O, K ₂ O has the greatest effect of improving the dielectric constant, followed by Na ₂ O. In RO, BaO is the most effective, followed by SrO and ZnO. Therefore, it is preferable to select and use these components preferentially.

TiO ₂ is a component that exhibits the effect of improving the dielectric constant ε when coexisting with an alkaline earth oxide. It is also a component that has the effect of shielding ultraviolet rays generated from the lamp. On the other hand, if the content is too large, TiO ₂ crystals are precipitated, which hinders glass forming. If the content of TiO ₂ is 5% or less, stable glass forming can be performed without precipitation of TiO ₂ crystals.

CeO ₂ is a component having an effect of shielding ultraviolet rays generated from the lamp. Moreover, it is a clarifier component that improves foaming when the glass is melted. On the other hand, if the content is increased, the glass is colored yellow, which is not preferable as an outer container. Therefore, the CeO ₂ content is limited to 3% or less. If it exceeds 3%, the glass is markedly yellow, which is not preferable.

WO ₃ and Nb ₂ O ₅ are components having an effect of shielding ultraviolet rays generated from the lamp, and can be added up to 3% as necessary. Further, since these components are filled in the gaps of the glass skeleton, the dielectric constant ε is also improved. However, if it exceeds 3%, the glass is devitrified, which is not preferable.

In addition to the above, ZrO ₂ , Fe ₂ O ₃ , Sb ₂ O ₃ , As ₂ O ₃ , PbO, Y ₂ O ₃ , Ga ₂ are considered to be effective in improving the dielectric constant ε by filling the gap in the glass skeleton. Various components such as O ₃ , MoO ₃ , rare earth oxide, and lanthanoid oxide can be added. Further, it is possible to contain 1% or less each of SO ₂ , Cl _{2 and the} like as a fining agent.

In the outer container of the present invention, the preferred composition range of the glass constituting the container is, by mass%, SiO ₂ 45-60%, B ₂ O ₃ 0-8%, Al ₂ O ₃ 0-8%, MgO 0 8%, CaO 0-8%, SrO 0-8%, BaO 7.5-25%, ZnO 0-12%, TiO ₂ 0-5%, CeO ₂ 0-3%, ΣRO (= MgO + CaO + SrO + BaO + ZnO) 25- 40%, ΣR ₂ O (= Li ₂ O + Na ₂ O + K ₂ O) 5 to 9.8%, particularly desirable range is mass%, SiO ₂ 48 to 58%, B ₂ O _{3 0 to} 7.5% _{, Al 2 O 3 0~7%,} 0~8% MgO, CaO 0~8%, SrO 0~8%, BaO 7.5~22.5%, 0~12% ZnO, TiO 2 0~5% , CeO ₂ 0 to 2%, ΣRO (= MgO + CaO + SrO + BaO + ZnO) 25 ˜38%, ΣR ₂ O (= Li ₂ O + Na ₂ O + K ₂ O) 5 to 9.8%.

  Next, a method for manufacturing the outer electrode fluorescent lamp outer casing of the present invention will be described.

  First, the case of manufacturing a tubular envelope will be described.

  The raw materials are prepared so as to have the above composition, mixed, and then melted in a melting furnace. At this time, the amount of water in the glass is adjusted as necessary. Next, the molten glass is formed into a tubular shape by using a tube drawing method such as the Danner method, the down draw method, or the up draw method. Thereafter, the outer glass fluorescent lamp envelope can be obtained by cutting the tubular glass into a predetermined size and post-processing as necessary.

  Next, a method for producing a flat outer jacket will be described.

  The raw materials are prepared so as to have the above composition, mixed, and then melted in a melting furnace. At this time, the amount of water in the glass is adjusted as necessary. Next, the molten glass is formed into a sheet by a method such as an overflow method, a float method, or a slot down method. Thereafter, the plate-like glass is cut into a predetermined size and post-processed as necessary to obtain a back plate. Further, by re-forming the plate glass produced in the same manner by press working or the like, one or a plurality of concave portions serving as discharge spaces are formed. In this way, a front plate is obtained. Thereafter, the front plate and the back plate are sealed using a sealing material or the like. In addition, you may apply | coat a fluorescent substance to the predetermined location of a front plate and a back plate beforehand. Thus, a flat outer electrode fluorescent lamp envelope having one or a plurality of discharge spaces can be obtained.

  Using the obtained outer casing, an external electrode fluorescent lamp can be produced according to a conventional method. Prior to assembling the fluorescent lamp, electrodes can be formed on the outer surface of the outer casing, for example, in the vicinity of both ends in the case of a tubular outer casing, and on the back plate in the case of a flat outer casing. .

  Hereinafter, the present invention will be described based on examples. Tables 1 to 3 show examples (samples Nos. 1 to 13) of glass constituting the outer container of the present invention, and Tables 4 to 6 show comparative examples (Nos. 14 to 24).

  First, glass raw materials were prepared so as to have the composition shown in the table, and then melted at 1500 ° C. for 5 hours using a platinum crucible. After melting, the melt was shaped into a predetermined shape and processed to prepare each glass sample. As the raw material, natural minerals, oxides, carbonates, sulfates and the like can be used, and the raw material may be prepared in consideration of the analytical value of the raw material, and the type of the raw material is not limited.

  Next, various characteristics of the obtained glass samples were evaluated. The results are shown in Tables 7-12.

  For the dielectric constant ε and dielectric loss tangent tan δ at 1 MHz, room temperature, and volume resistivity log ρ at 250 ° C., a plate-like sample having a size of 50 × 50 × 3 tmm is prepared from each glass sample, and a 30 mmφ electrode is attached. , Measured with an LCR meter. The measurement conditions for dielectric constant ε and dielectric loss tangent tan δ were 1 MHz and 25 ° C.

  Evaluation of dielectric constant ε and dielectric loss tangent tan δ at 40 KHz was performed as follows. First, as shown in FIG. 3, a # 1000-finished disk-shaped sample G having a diameter of 20 mm and a thickness of 1 mm is prepared, and a main electrode a having an outer diameter of 14.5 mm and a concentric outer surface of the main electrode a are provided on one side. A guide electrode b having an outer diameter of 20 mm and an inner diameter of 16 mm provided in the above was produced by gold vapor deposition. On the other surface of the sample, a counter electrode c was formed on the entire surface by gold vapor deposition.

  As shown in FIG. 4, the measuring apparatus has a structure including a heater 100, a sample measuring chamber 110, and an LCR meter (not shown). The heater is a non-dielectric wound tape heater. The sample measurement chamber 110 is installed in a shield (metal cylinder) 120 in order to avoid electromagnetic induction due to the influence of the heater 100. In the sample measurement chamber 110, a main electrode terminal 111 for contacting the main electrode a of the sample G and a guard electrode terminal 112 for contacting the guard electrode b are provided so as to be able to move up and down integrally. The main electrode terminal 111 is connected to the terminal of the LCR meter, and the guard electrode terminal 112 is connected to the guard terminal of the LCR meter via the conducting wires. In addition, a counter electrode terminal 113 for contacting the counter electrode c of the sample G is provided in the upper part of the sample measuring chamber 110. The counter electrode terminal 113 is connected to the terminal of the LCR meter via a conducting wire. In addition, a shield (aluminum foil, not shown) is provided between the conductive wire of the counter electrode terminal 113 and the conductive wire of the main electrode terminal 111 so as not to be affected. A thermocouple 114 connected to a thermometer is installed in the vicinity of the sample G held in the sample measurement chamber 110 so that the sample temperature can be measured.

  In order to measure the dielectric characteristics of the sample G using the measuring apparatus, first, the sample G is placed on the main electrode terminal 111 and the guard electrode terminal 112. Next, both terminals are moved upward, and the sample G is held in a state of being pressed against the counter electrode terminal 113 installed at the upper part. Subsequently, the sample G is heated by the heater 100, and the dielectric characteristics when the temperature reaches a predetermined temperature are measured by an LCR meter. Thus, the dielectric loss tangent was measured under conditions of room temperature-1 MHz, 40 KHz-150 ° C., 40 KHz-250 ° C., 40 KHz-350 ° C.

  The thermal expansion coefficient α was measured with a thermal expansion measuring device.

  The liquid phase viscosity was determined as follows. First, glass crushed to a particle size of about 0.1 mm was placed in a boat-shaped platinum container, held in a temperature gradient furnace for 24 hours, and then taken out. The sample is observed with a microscope to measure the temperature at which the initial phase of the crystal appears (liquidus temperature), and then the viscosity corresponding to the temperature of the initial phase is determined from the relationship between the temperature and viscosity of the glass measured in advance. The (liquidus viscosity log ρ) was determined.

  The temperature corresponding to the viscosity was determined by ASTM C336, ASTM C338 and the ball pulling method.

  A method for producing a tube-type external electrode fluorescent lamp envelope using a glass having the same composition as the glass sample used in Example 1 will be described.

  First, the raw materials prepared so as to be the same glass as each sample are melted in a refractory kiln at 1500 ° C. for 24 hours. Thereafter, the glass melt is supplied to a dunner forming apparatus, and is drawn and cut to obtain a glass tube having an outer diameter of 3.0 mm, a wall thickness of 0.3 mm, and a length of 800 mm, which is used as an outer container. Can do.

  The outer container thus obtained is used for manufacturing a tube-type external electrode fluorescent lamp.

  A method for producing a casing for a flat-type external electrode fluorescent lamp using a glass having the same composition as the glass sample used in Example 1 will be described.

  First, the raw materials prepared so as to be the same glass as each sample are melted at 1500 ° C. in a refractory kiln. Thereafter, the glass melt is supplied to a float forming apparatus, drawn, and cut to obtain a plate glass having a size of 300 × 200 mm and a thickness of 0.9 mm, which is used as a back plate for an outer container. Similarly, a plate glass having a size of 300 × 200 mm and a thickness of 0.9 mm is pressed by a mold to form a recess for forming a discharge space, thereby obtaining a front plate for an outer container.

  The back plate and the front plate obtained in this way are joined in advance to form a box (outer container), and then used for the manufacture of a flat-type external electrode fluorescent lamp. Alternatively, it is joined during the manufacturing process of the lamp or in the final process to form the outer casing of the flat type external electrode fluorescent lamp.

It is explanatory drawing which shows a planar type external electrode fluorescent lamp. It is explanatory drawing which shows a tube-type external electrode fluorescent lamp. It is explanatory drawing which shows the sample which measures a dielectric property, (a) is the figure which looked at the sample from the side surface, (b) has shown the figure which looked at the sample from the bottom face side. It is explanatory drawing which shows the apparatus which measures a dielectric property.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Back plate for outer packaging 2 Front plate for outer packaging 3 Electrode 4 Phosphor 5 Spacer 6 Mantle tube 10 Power supply L, L1, L2 External electrode fluorescent lamp

Claims (11)

An outer casing used in the manufacture of an external electrode fluorescent lamp having a structure in which an electrode is provided on the outer surface, and in terms of mass%, SiO ₂ 45-60%, B ₂ O ₃ 0-10%, Al ₂ O ₃ 0 ~10%, 0~10% MgO, CaO 0~10%, SrO 0~9%, BaO 5~25%, ZnO 0~13%, TiO 2 0~5%, CeO 2 0~3%, ΣRO ( = MgO + CaO + SrO + BaO + ZnO) 20 to 40%, ΣR ₂ O (= Li ₂ O + Na ₂ O + K ₂ O) A glass container containing 5 to 9.8%. The outer electrode lamp envelope according to claim 1, wherein Li ₂ O / ΣR ₂ O is 0.4 or less in terms of mass ratio. 3. The outer electrode lamp envelope according to claim 1, wherein Na ₂ O / ΣR ₂ O is 0.6 or less in terms of mass ratio. 4. The external electrode lamp according to claim 1, wherein (ΣRO + ΣR ₂ O) / (SiO ₂ + B ₂ O ₃ + Al ₂ O ₃ ) is 0.55 to 0.85 in terms of mass ratio. A mantle container. 5. The outer electrode lamp envelope according to claim 1, comprising a glass having a thermal expansion coefficient α at 30 to 380 ° C. of 70 to 90 × 10 ⁻⁷ / ° C. 6.   The outer electrode lamp envelope according to any one of claims 1 to 5, wherein said outer electrode lamp envelope is made of glass having a dielectric constant ε of 6.5 MHz or more at room temperature and a dielectric loss tangent tan δ of 0.003 or less.   The outer electrode lamp jacket according to any one of claims 1 to 6, wherein the outer electrode lamp outer shell is made of glass having a volume resistivity log ρ at 250 ° C of 9.5 or more.   The outer electrode lamp envelope according to any one of claims 1 to 7, which is made of glass having a dielectric constant ε of 7 or more and a dielectric loss tangent tan δ of 0.01 or less at 40 KHz and 150 ° C.   The outer electrode lamp envelope according to any one of claims 1 to 8, which is made of glass having a dielectric constant ε of 7 or more and a dielectric loss tangent tan δ of 0.02 or less at 40 KHz and 250 ° C.   The outer electrode lamp envelope according to any one of claims 1 to 9, wherein the outer electrode lamp envelope is made of glass having a dielectric constant ε of 7 or more at 40 KHz and 350 ° C and a dielectric loss tangent tan δ of 0.1 or less.   The outer electrode lamp outer casing according to any one of claims 1 to 10, wherein the outer electrode lamp outer shell is made of glass having a liquidus viscosity logη of 5.2 or more.

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