JP2007131530A - Glass for fluorescent lamp, glass tube for fluorescent lamp and fluorescent lamp - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide glass for a fluorescent lamp which is not discolored into black upon production, and further has characteristics equal to or above those of the conventional soda lime glass, to provide a glass tube for a fluorescent lamp composed of the glass, and to provide a fluorescent lamp produced using the glass tube. <P>SOLUTION: The fluorescent lamp is produced by using the glass tube composed of soda lime glass comprising, by weight, 2 to 9% CaO, 0.9 to 6.9% K<SB>2</SB>O and 0 to 3% BaO, and having an Sb<SB>2</SB>O<SB>3</SB>content of ≤0.1% and a TiO<SB>2</SB>content of 0.05 to 10% for its envelope. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a glass for a fluorescent lamp.

  Fluorescent lamps generally have a straight tube or an annular shape that is a heat-processed straight tube, but recently, the straight tube has been bent into a U-shape or a W-shape, and several straight tubes are used. Twin tubes that are arranged in parallel and joined together, and special shapes called compact tubes have also been developed.

Initially, the glass tubes used in the envelopes of these ring-shaped and special-shaped fluorescent lamps are made of low-viscosity lead glass containing a relatively large amount of PbO of about 20 to 30% in order to facilitate processing. However, it has now been switched to soda lime glass to avoid PbO toxicity problems. The soda-lime glass used in this application introduces BaO as a component to lower the viscosity in order to have processability close to that of PbO-containing glass, and to maintain and maintain the high brightness required for fluorescent lamps. In particular, it contains Sb ₂ O ₃ and is specially improved for fluorescent lamp applications.
JP 56-11848 A JP-A-9-106784 JP-A-6-56467 Japanese Patent Laid-Open No. 51-86515 JP-A-10-152340 US Pat. No. 5,843,856 US Pat. No. 5,843,855 Japanese Patent Laid-Open No. 11-224649

  However, when a fluorescent lamp is manufactured using the above-mentioned soda-lime glass tube as an envelope, the glass is discolored black at the time of manufacture, which often causes a problem that a high-intensity lamp cannot be obtained. ing.

  An object of the present invention is to provide a fluorescent lamp glass having the same or better characteristics than conventional soda lime glass, and a glass tube for a fluorescent lamp made of this glass. It is to provide a fluorescent lamp manufactured using the same.

The reason why the glass changes to black is that Sb ₂ O ₃ contained in the glass is a component that is easily reduced, and is affected by the burned state of the burner during the processing step, thereby forming a metal colloid. Therefore, as a result of various investigations by the present inventors, in order to prevent this, it is necessary that the glass component does not contain Sb ₂ O ₃ as much as possible, and TiO as a component that replaces Sb ₂ O _3. It has been found that a predetermined amount of ₂ should be contained.

That is, the glass for a fluorescent lamp of the present invention has 2 to 9% by weight of CaO, 0.9 to 6.9% by weight of K ₂ O, 0 to 3% by weight of BaO, and 0.1% of Sb ₂ O ₃ content. It is characterized by being made of soda lime glass having a TiO ₂ content of 0.05 to 10% by weight.

Further, the glass tube for a fluorescent lamp of the present invention is characterized by comprising a glass having an Sb ₂ O ₃ content of 0.1% by weight or less and a TiO ₂ content of 0.05 to 10% by weight. To do.

In the fluorescent lamp of the present invention, a glass tube having an Sb ₂ O ₃ content of 0.1% by weight or less and a TiO ₂ content of 0.05 to 10% by weight is used as an envelope. Features.

As described above, the glass for a fluorescent lamp of the present invention does not substantially contain Sb ₂ O _3, and therefore blackening does not occur at the time of burner processing. In addition, by containing TiO ₂ , the amount of alkali elution of the glass can be reduced, ultraviolet coloring can be suppressed, and the processing temperature can be lowered.

  Moreover, since the glass tube for fluorescent lamps of the present invention is made of glass having the above characteristics, it is possible to produce a fluorescent lamp with high luminance and little luminance deterioration. Moreover, since it is easy to mold, it is suitable as an envelope for a fluorescent lamp having an annular shape or special shape by heat processing as well as a straight tube.

In addition, the fluorescent lamp of the present invention has high luminance and little luminance deterioration, although it does not substantially contain Sb ₂ O ₃ .

The glass for a fluorescent lamp of the present invention contains TiO ₂ as an essential component instead of Sb ₂ O ₃ , whereby a fluorescent lamp having high luminance and little luminance deterioration can be produced.

If the content of Sb ₂ O ₃ exceeds 0.1%, Sb colloid is generated during the processing step and the color is changed to black, so that a high-intensity fluorescent lamp cannot be obtained. Note Sb ₂ O ₃ content _of it is desirable not to contain.

The content of TiO ₂ is 0.05 to 10%, preferably 0.2 to 5%. TiO ₂ is an essential component for obtaining a fluorescent lamp with high luminance and little luminance deterioration, and has an effect of increasing the workability and productivity in the fluorescent lamp process by appropriately reducing the viscosity of the glass.

The brightness of the fluorescent lamp and the degree of its deterioration are not only the decrease in the transmittance due to the blackening of the glass due to Sb ₂ O _3, but also the contamination of the phosphor and the consumption of mercury caused by the elution components from the glass such as alkali metals. It depends on factors such as a decrease in the transmittance of the glass due to ultraviolet coloring (solarization). In addition, in the case of an annular or special-shaped fluorescent lamp that is heat-processed after the phosphor is applied, if the processing temperature is high, the phosphor deteriorates and contributes to a decrease in luminance.

TiO ₂ can reduce the amount of alkali elution of glass, reducing the ultraviolet colored, and because the action of lowering the processing temperature is high, small fluorescent lamp brightness deterioration can be thus obtained at a high luminance.

In order to obtain this effect, it is necessary to add 0.05% or more of TiO _2, and the effect increases as the amount increases. However, if the amount increases too much, devitrification occurs when the glass is melted and stable production cannot be achieved, or the glass is colored yellow to impair the color tone of the fluorescent lamp, so the limit is 10%.

Moreover, it is desirable that the glass for a fluorescent lamp of the present invention does not contain toxic components such as PbO and As ₂ O _{3, and} even if it is contained, it is preferably limited to 0.1% or less. This is due to the recent increase in awareness of environmental pollution issues and the strengthening of legal regulations. PbO and As ₂ O ₃ are components that are easily reduced to form a metal colloid, like Sb ₂ O _3, and it is preferable not to contain them from this point.

The preferred composition range of the glass for a fluorescent lamp of the present invention is, as a percentage by weight, SiO ₂ 60 to 75%, Al ₂ O ₃ 0.5 to 10%, B ₂ O ₃ 0 to 5%, RO 3 to 17%. (R represents Ca, Mg, Sr, Ba, Zn), R ′ ₂ O 10-22% (R ′ represents Li, Na, K), ZrO ₂ 0-5%, CeO ₂ 0-2% Fe ₂ O ₃ 0.01 to 0.4%, P ₂ O ₅ 0 to 1%, TiO ₂ 0.05 to 10%.

  The reasons for limiting the glass composition will be described below.

SiO ₂ is an essential component for forming a glass matrix. However, when it exceeds 75%, the viscosity becomes very high, the workability during the production of the fluorescent lamp is greatly impaired, and it is difficult to melt even during the production of the glass tube. It becomes a glass with a lot of bubbles, striae, striae, and bubbles. On the other hand, if it is less than 65%, the thermal expansion coefficient becomes too large, and the consistency of the expansion coefficient with the stem glass cannot be obtained. Furthermore, the chemical durability is greatly reduced, which causes a reduction in luminance. Incidentally preferred range of SiO ₂ is 62 to 73%.

Al ₂ O ₃ has a high effect of improving the weather resistance of the glass and is effective in suppressing the devitrification of the glass, but the effect is small at less than 0.5%, and when it exceeds 10%, The viscosity increases rapidly, making it difficult to melt the glass and to bend the fluorescent lamp. Note preferable range of Al ₂ O ₃ is from 0.5 to 5%.

B ₂ O ₃ is a component that reduces the viscosity of the glass and further improves the weather resistance, and is preferably added. However, if it exceeds 5%, the weather resistance reverses and evaporation at the time of melting increases, so that a glass with high homogeneity cannot be obtained. Therefore, 5% is the limit. Incidentally preferred range for B ₂ O ₃ is 0 to 2%.

  RO (R represents Ca, Mg, Sr, Ba, and Zn) has an action of promoting the melting of the glass and increasing the weather resistance of the glass. In addition, the effect of reducing the viscosity is great. However, if RO is less than 3%, a sufficient effect cannot be obtained. On the other hand, if it exceeds 17%, the devitrification property of the glass increases, and a highly homogeneous glass cannot be obtained. Moreover, since the change of the viscosity with respect to the temperature becomes rapid, it becomes difficult to precisely form and process the glass tube while hot. In addition, the preferable range of RO is 5 to 15%. The content of each component is suitably CaO 2-9%, MgO 1-9%, SrO 0-7%, BaO 0-3%, ZnO 0-5%. However, with respect to BaO, it is desired to reduce the amount used as much as possible from the viewpoint of the environment. From this viewpoint, it is desirable to limit it to 0.1% or less.

R′O (R ′ represents Li, Na, K) is essential for setting the linear thermal expansion coefficient of the glass to 90 to 105 × 10 ⁻⁷ / ° C. that matches the stem glass and lowering the viscosity. It is a component. It also has a great effect as a flux. If the content is less than 10%, this effect becomes insufficient. Also, if it exceeds 22%, the coefficient of linear thermal expansion becomes too large and it is easy to elute from the glass, so it reacts with phosphors and mercury to lower the brightness of the fluorescent lamp and provides sufficient weather resistance for long-term use. It becomes impossible. A preferable range of R′O is 15 to 20%. The content of each _{component, Li 2 O 0~3%, Na} 2 O 7~19%, it is preferred that K ₂ O 0.9~6.9%.

ZrO ₂ has an effect of improving the weather resistance of the glass, so it is preferable to add it. However, as the amount increases, the devitrification of the glass increases and stable melting of the glass becomes impossible. For this reason, the upper limit of ZrO ₂ is limited to 5%. A preferable range of ZrO ₂ is 0 to 2%.

CeO ₂ is a component having a large action of absorbing ultraviolet rays. For this reason, when it is desired to enhance the effect of preventing leakage of ultraviolet rays to the outside of the lamp, it is preferable to add a small amount. Moreover, since there exists an effect | action as a clarifier, the bubble quality of glass can be improved. However, if it exceeds 2%, there is a problem that the coloring of the glass becomes remarkable. A preferable range of CeO ₂ is 0 to 1.5%.

Although Fe ₂ O ₃ is not an essential component, it is often contained in an amount of about 0.01% or more as an impurity of the raw material. Since Fe ₂ O ₃ has the same effect as CeO ₂ , it may be positively added up to 0.4%, but if it exceeds this, the glass will be remarkably colored like CeO ₂ . Note preferable range of Fe ₂ O ₃ is 0.01 to 0.2%.

P ₂ O ₅ lowers the liquidus temperature of the glass and suppresses devitrification, so it can be added in a small amount, but if it exceeds 1%, the glass becomes milky, which is not preferable. Note preferable range of P ₂ O ₅ is 0.1 to 0.8%.

  Next, a method for producing a fluorescent lamp using the fluorescent lamp glass of the present invention will be described.

  First, batches are prepared by blending glass raw materials so as to have a desired composition.

  Next, the batch is put into a glass melting furnace, and after vitrification in a tank type continuous melting furnace at 1500 to 1600 ° C., the glass is formed into a tubular shape by a Dunner method, a down draw method, an up draw method, etc. Cut into pieces to obtain a glass tube.

  Subsequently, an envelope for a fluorescent lamp is manufactured by processing the glass tube into a desired shape such as drawing at both ends.

  Thereafter, application of a phosphor, attachment of a stem, exhaust, encapsulation of mercury or Ar gas, and the like are performed. In the case of an annular fluorescent lamp or a specially shaped fluorescent lamp, the fluorescent lamp is obtained by further bending.

  Next, this invention is demonstrated based on an Example.

  Tables 1-3 show examples of the present invention (sample Nos. 1 to 14) and comparative examples (samples No. 15 and 16). Sample No. Reference numeral 15 denotes a conventional fluorescent lamp glass made of soda lime glass.

  Each sample was produced as follows.

  First, the raw material powder of the quantity defined so that it might become the target glass composition was weighed and mixed, it put into the crucible made from platinum, and it melt | dissolved at 1550 degreeC in the electric furnace. After the raw materials were sufficiently dissolved, a stirring blade was inserted into the glass melt and stirred for about 2 hours. Next, after taking out a stirring blade and leaving still for 30 minutes, it produced by shape | molding and processing into a shape required for a measurement.

  The obtained samples were evaluated for linear thermal expansion coefficient, working temperature, alkali elution amount, and ultraviolet solarization resistance.

Each measurement was performed as follows. As the linear thermal expansion coefficient, a columnar sample having an outer diameter of 3.5 mm and a length of 50 mm was prepared, and an average linear thermal expansion coefficient between 30 to 380 ° C. was measured with a dilatometer. The glass working temperature was determined by a platinum ball pulling method based on Stokes' law, and a glass viscosity of 10 ⁴ poise was obtained. This working temperature is used as a guide for heat processing when making a fluorescent lamp having an annular shape or a special shape, and it is preferable that the temperature is lower in order to prevent efficient processing or deterioration of the phosphor. The alkali elution amount of glass was measured by the powder method based on JIS-R3502 and the amount of alkali components eluted in pure water. If the amount of alkali elution is large, the phosphor is altered or reacts with mercury, leading to deterioration in luminance. The ultraviolet solarization resistance was evaluated as follows. First, a sample having a thickness of 1 mm with both surfaces mirror-polished was prepared, and the transmittance at a wavelength of 400 nm was measured. Subsequently, after irradiating ultraviolet rays having a main wavelength of 253.7 nm with a 40 W low-pressure mercury lamp for 60 minutes, the transmittance at 400 nm was measured again, and the amount of decrease in the transmittance due to ultraviolet irradiation was determined and indicated as ΔT%. The lower the ultraviolet solarization resistance, the greater the reduction in the transmittance, and the more the luminance of the fluorescent lamp deteriorates.

As is apparent from the table, each sample of the present invention containing TiO ₂ as an essential component is a glass substantially free of Sb ₂ O ₃ , while the working temperature is 969 ° C. or less and the alkali elution amount is 0. 79 mg or less, and the UV solarization resistance is 1.0% or less, and the conventional sample No. It was found to have a property equal to or better than 15.

On the other hand, No. which is a comparative example. Sample No. 16 had a coefficient of linear thermal expansion of 97.4 × 10 ⁻⁷ / ° C. that can be safely sealed from the stem glass, but the working temperature was as high as 987 ° C. and the amount of alkali elution was as high as 0.86 mg. . Furthermore, with respect to the ultraviolet solarization resistance, the decrease in transmittance due to ultraviolet irradiation was 9.3%, which was extremely bad.

  Next, sample no. A 30 W annular fluorescent lamp was fabricated using 5, 8, 11, 15, and 16 glasses. Subsequently, the initial luminance and the luminance after 1000 hours of lighting were compared with the conventional sample Nos. The relative luminance is shown when the initial luminance of 15 is 100%.

As a result, no. The fluorescent lamps 5, 8, and 11 showed the same or better performance than the fluorescent lamps made of conventional glass.

Claims (5)

CaO is 2-9 wt%, K ₂ O is from 0.9 to 6.9 wt%, BaO 0 to 3 wt%, Sb ₂ O ₃ content is 0.1 wt% or less, and, TiO ₂ content A glass for a fluorescent lamp, characterized by comprising soda-lime glass having an amount of 0.05 to 10% by weight. _{2. The} glass for a fluorescent lamp according to claim 1, wherein the contents of PbO and As ₂ O ₃ are each 0.1% by weight or less. In weight percent, expressed _{SiO 2 60~75%, Al 2 O} 3 0.5~10%, B 2 O 3 0~5%, RO 3~17% (R is Ca, Mg, Sr, Ba, and Zn ), R ′ ₂ O 10-22% (R ′ represents Li, Na, K), ZrO ₂ 0-5%, CeO ₂ 0-2%, Fe ₂ O ₃ 0-0.4%, P ₂ O ₅ 0 to 1%, fluorescent lamp glass according to claim 1 or 2, characterized in that it consists of TiO ₂ 0.05 to 10%.   A glass tube for a fluorescent lamp, comprising the glass according to any one of claims 1 to 3.   A fluorescent lamp using the glass tube of claim 4 as an envelope.