WO2007086441A1

WO2007086441A1 - Process for producing glass composition for lamp, glass composition for lamp, and lamp

Info

Publication number: WO2007086441A1
Application number: PCT/JP2007/051106
Authority: WO
Inventors: Atsushi Motoya; Yasurou Niguma
Original assignee: Matsushita Electric Industrial Co., Ltd.
Priority date: 2006-01-30
Filing date: 2007-01-24
Publication date: 2007-08-02
Also published as: JPWO2007086441A1; CN101374776A

Abstract

A process for producing a glass composition for lamps which includes a melting step in which a raw-material mixture containing an oxide of a given element and a hydroxide of the given element in an oxide/hydroxide proportion of from 1/3 to 1 by mole is melted and brought into a vitreous state. In the melting step, the raw-material mixture is heated so that the hydroxide undergoes a decomposition reaction to generate a gas comprising at least either of H2O and H2. Thus, a glass reduced in bubble inclusions can be produced without generating any harmful gas.

Description

Specification

Technical field of manufacturing glass composition for lamp, glass composition for lamp and lamp technical field

The present invention relates to a method for producing a glass composition for lamps, a glass composition for lamps produced using this method, and a lamp produced using this glass composition for lamps. Background art

In general, a fluorescent lamp is used as a light source in a backlight of a transmissive liquid crystal display element such as a liquid crystal TV or a personal computer display. The fluorescent lamp for backlight has basically the same configuration as the fluorescent lamp for general illumination, but the tube diameter of the glass bulb is smaller and the wall thickness is thinner. Therefore, such fluorescent lamps for backlight use borosilicate hard glass (hereinafter simply referred to as “borosilicate glass”) having high mechanical strength and excellent electrical insulation.

[0003] By the way, if air bubbles are present in the glass of the glass bulb, the mechanical strength of the glass bulb is reduced and breakage is likely to occur. Such a decrease in strength becomes a serious problem particularly in a glass bulb having a small tube diameter and a small thickness. Therefore, conventionally, arsenic or antimony is added to glass as a fining agent, and bubbles are removed from the glass (glass is clarified).

However, the arsenic antimony is an environmentally hazardous substance that adversely affects the environment. Therefore, glass with arsenic antimony added is not suitable for recycling. In addition, arsenic and antimony-added glass must be handled with care in manufacturing and disposal plants, and requires extensive facilities for detoxification of etching wastewater.

In order to deal with this type of problem, Patent Document 1 contains SO, CI, and F as fining agents.

Three

A method for producing glass in which an effective amount of a salt is added is disclosed. With this method, it is possible to obtain a glass with less bubbles without adding an environmental load substance. It is also known that a clarification effect can be obtained by adding nitrates such as Na NO and KNO to the glass.

3 3

ing.

Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-284949 Disclosure of the invention

Problems to be solved by the invention

[0005] However, the manufacturing method of Patent Document 1 generates a gas harmful to the human body such as a sulfide-based gas or a halogen-based gas during the glass melting step. Such harmful gas generation is preferable because it deteriorates the working environment of glass production.

Also, when nitrate is added, nitric acid gas (NOx) harmful to the human body is generated and the working environment for glass production is deteriorated.

[0006] An object of the present invention is to provide a method for producing a glass composition for a lamp capable of producing a glass with few remaining bubbles without generating harmful gas. Another object of the present invention is to provide a glass composition for a lamp with few bubbles that can be produced without generating harmful gases, and a lamp that is formed from the glass composition for a lamp and is less likely to break. It is to provide.

Means for solving the problem

[0007] In order to achieve the above object, a method for producing a glass composition for a lamp according to an embodiment of the present invention is such that an oxide of a predetermined element and a hydroxide of the predetermined element are oxide / hydroxide. = A melting step of melting a raw material mixture added at a molar ratio of 1/3 to 1 into a glass state, and in the melting step, H 0 or H Heating the raw material mixture so that a gas comprising at least one of the above is generated is a special number.

[0008] A glass composition for a lamp according to an embodiment of the present invention is a glass composition for a lamp produced by the above-described method for producing a glass composition for a lamp, and transmits infrared light in the wavelength region near 3620 cm- ¹ . It is characterized by a minimum value of 3.0 to 4.5% at a sample thickness of 2 mm.

A lamp according to an embodiment of the present invention is characterized by including a glass bulb formed of the above glass composition for a lamp.

The invention's effect

[0009] A method for producing a glass composition for a lamp according to the present invention comprises the steps of: Since a gas composed of at least one of HO and H is generated from the hydroxide, it has the effect of being able to produce glass with few bubbles without generating harmful gas. The effect will be described in detail below.

As a result of various studies, the present inventors have replaced a part of the oxide of the predetermined element added to the raw material mixture with the hydroxide of the predetermined element, thereby melting the raw material mixture into a glass state. In the process, it was found that gas was generated from the hydroxide, and bubbles in the glass melt were removed by the gas, and a clarification effect was obtained. The gas generated from the hydroxide is generated by a decomposition reaction of the hydroxide and consists of at least one of H 0 and H. Temperature range where the vitrification reaction starts 500

A clarification effect is obtained by the decomposition reaction of the hydroxide occurring at ˜1000 ° C.

[0010] In the first place, the bubbles present in the glass are those in which the gas such as CO generated when the raw material mixture melts into the glass state remains without being able to escape from the glass melt. In particular,

The CO bubbles are small in diameter, have a low buoyancy, and are difficult to lift from the glass melt, so they cannot easily escape from the glass melt and remain in the glass.

In order to remove such small-sized bubbles, the glass for a lamp according to the present invention generates H 0 or H force gas from the hydroxide of a predetermined element. This H 0 or H

2 2 2 2 Gas bubbles with a larger diameter are larger than bubbles of CO, etc., so the buoyancy is greater. Glass melt melt force Easily escapes and does not remain in the glass. Since the gas bubbles composed of H 0 and H take in bubbles such as CO when rising from the glass melt, small diameter bubbles composed of CO and the like are also removed from the glass.

[0011] However, when a gas having H 0 or H force is generated in the glass melt, there is a problem that moisture tends to remain in the glass. If a lamp has a large amount of water remaining in the glass and the water vaporizes when heated, refoaming (reboiling) is likely to occur. Foaming can cause slow leaks and cracks.

[0012] In order to solve this problem, the present inventors set the mixing ratio of the oxide and the hydroxide in the range of 1/3 to 1, thereby causing re-foaming while obtaining a sufficient clarification effect. Can be difficult I found out.

When the mixing ratio is large, the clarification effect is insufficient because the generation amount of H 0 or H force gas is small. On the other hand, if the mixing ratio is less than 1/3, re-foaming is likely to occur during heat processing, which is not suitable for lamps.

[0013] As the predetermined element, boron (B), aluminum (A1), calcium (Ca), and the like are conceivable. In this case, the hydroxide of the predetermined element is H BO, Al (OH), respectively. And Ca

3 3 3

Means (OH).

Note that the hydroxide according to the present invention includes a hydroxide in a narrow sense, that is, a compound having a hydrogen element and an oxygen element in a broad sense that includes only a compound having a hydroxyl group. For example, H BO (B

It can also be marked as (OH). ) And a broad hydroxide.

[0014] In the method for producing a glass composition for a lamp according to the present invention, the oxide and the hydroxide have a content of the predetermined element in the glass composition for a lamp of 8 to 17 mol% in terms of oxide. Thus, when added to the raw material mixture, it is possible to obtain a glass composition for a lamp that is excellent in meltability and sealing property of the lead-in wire and that hardly causes phase separation.

The method for producing a glass composition for a lamp according to the present invention is such that the hydroxide has a content of the predetermined element in the glass composition for a lamp of 5 to 10.5 mol% in terms of oxide. When added to the raw material mixture, it is possible to obtain a glass composition for a lamp in which re-foaming hardly occurs at the time of heat caching with few bubbles.

[0015] In the method for producing a glass composition for a lamp according to the present invention, when the glass composition for a lamp is a borosilicate glass and the predetermined element is boron, the clarification effect is particularly remarkable. For example, H BO, which is a hydroxide of boron, decomposes in a wide temperature range of 300 to 800 ° C.

3 3

As a result, a gas composed of at least one of H 0 and H is generated, so that temperature control is easy in the melting step. The decomposition reaction of HBO is represented by the following (formula 1) and (formula 2).

[0016] 2H BO → 3H 0 + B ○ · · · (Formula 1)

2H BO → 3/20 + 3H + B〇 (2)

Furthermore, the use of inexpensive HBO has the effect that glass can be produced at a low cost, and HBO has the effect that even if a large amount of glass is added, the glass is not colored. In the present invention, the borosilicate glass is a glass having a high Young's modulus and Vickers hardness and excellent mechanical strength, and specifically, a glass containing 6 to 20 mol% of B 0 in terms of oxide. Means.

[0017] Lamp glass composition according to the present invention, the thermal expansion coefficient (a) is 34 X 10- ⁷ / K~43 X 1

For 0_ ⁷ / kappa, or, the following effects in the case of ^{43 X 10- 7 / Κ~55 X 10-} 7 / Κ. In general, a knocklight lamp uses a lead wire made of tungsten or Kovar alloy that can withstand the high temperatures caused by discharge. Therefore, in order to increase the reliability of the hermetic seal of the lead-in wire, it is preferable to make the thermal expansion coefficient of the glass composition for lamps close to the thermal expansion coefficient of tungsten or Kovar alloy.

[0018] If the thermal expansion coefficient (alpha) is ^{34 X 10- 7 / Κ~43 X 10-} 7 / Κ, about the same as the thermal expansion coefficient of tungsten feedthrough, because high chemical durability, The reliability of the airtight seal of the lead-in line is high.

If the thermal expansion coefficient (a) is ^{43 X 10- 7 / K~55 X 10-} 7 / Κ, about the same as the thermal expansion coefficient of Kovar alloy feedthrough, because high chemical resistance, lead- High reliability of hermetic seal.

The lamp according to the present invention includes a glass bulb formed from the above glass composition for a lamp. Therefore, the lamp with few bubbles in the glass of the glass bulb is hardly damaged. Brief Description of Drawings

FIG. 1 shows the composition and properties of a glass composition according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a main configuration of a cold cathode fluorescent lamp according to an embodiment of the present invention.

FIG. 3 shows the composition and properties of a glass composition according to a comparative example.

FIG. 4 shows the infrared transmittance of a glass composition according to one embodiment of the present invention in the range of 2800 cm- ¹ to 3800 cm- ¹ .

FIG. 5 shows the infrared transmittance of a glass composition according to one embodiment of the present invention in the range of 3600 cm- ¹ to 3800 cm- ¹ .

Explanation of symbols

[0020] 1 lamp BEST MODE FOR CARRYING OUT THE INVENTION

[0021] A glass composition for a lamp, a method for producing the glass composition for a lamp, and a lamp according to an embodiment of the present invention will be described with reference to the drawings.

(Description of glass composition for lamp)

The composition of the glass composition according to the present embodiment is as shown in Examples 1 to 5 in FIG. Note that “%” in FIG. 1 means “mol%”.

[0022] The composition of the glass composition according to the present invention is not limited to the compositions shown in Examples 1 to 5, but in order to maintain the characteristics as a glass composition for a lamp, it is substantially converted in terms of oxide. , Si 0: 55 to 75 mol%, Al O: l to 10 mol%, BO + H BO: 8 to 17 mol%, Li O + Na O + KO: 0 to 12

2 2 3 2 3 3 3 2 2 2 mol%, LiO: 0-5 mol%, NaO: 0-8 mol%, KO: 0-12 mol%, MgO: 0.5-5 mol%, Ca

2 2 2

O: 0.5-10 mol%, SrO: 0-8 mol%, BaO: 0-10 mol%, CeO: 0.01-2 mol%, FeO: 0-0

2 2 3

It is preferable that they are 0.2 mol% and SnO: 0.01-5 mol%.

In the present embodiment, boron (B) contained in the glass composition is added to the raw material mixture as a boron oxide and added to the raw material mixture as a boron hydroxide. In order to distinguish these, “B 0” is used for those added as oxides, and “H BO” is used for those added as hydroxides.

2 3 3 3

. The same applies to FIG. 1 and FIG. 3 described later.

Therefore, in the above description, B 0 + H BO: The meaning described as 8 to 17 mol% means the glass composition

2 3 3 3

This means that the total amount of boron added as an oxide and boron added as a hydroxide in the product is 17 mol% in terms of oxide.

The reason for determining the glass composition for a lamp of the present invention as described above is as follows.

SiO is a component that forms a glass skeleton, and its content ranges from 55 to 75 mol%.

2

I like it. If it is less than 55 mol%, the thermal expansion coefficient becomes too high, and the chemical durability deteriorates. On the other hand, if it exceeds 75 mol%, the coefficient of thermal expansion becomes too low, making it difficult to process.

[0025] A10 is a component added for the purpose of improving the weather resistance and devitrification of glass.

twenty three

The content is preferably in the range of l ~ 10mol%. If the amount is less than lmol%, the above action is difficult to obtain. On the other hand, if it exceeds 10 mol%, the meltability of the glass deteriorates. Its content is particularly preferably 2-7 mol%. BO is an essential component of this embodiment, which is added for the purpose of improving the meltability of the glass, adjusting the expansion coefficient, and adjusting the viscosity.

[0026] HBO is an essential component of the present embodiment, which is added for the purpose of improving the meltability of glass, adjusting the expansion coefficient, adjusting the viscosity, and promoting the clarification effect.

B 0 + H BO is preferably in the range of 8-17 mol%. B 0 + H BO force Less than S8 mol%, the melting property of the glass deteriorates, the viscosity and expansion coefficient increase, and it becomes difficult to seal the lead-in wire. On the other hand, if it exceeds 17 mol%, the glass undergoes phase separation, making it difficult to produce the glass. The total content is particularly preferably 10 to 16 mol%.

[0027] B 0 and H BO are added so as to have a molar ratio of B 0 / H BO = 1/3 to 1. If the molar ratio is less than 1/3, re-foaming occurs in the overheated part by the burner during the thermal processing of the fluorescent lamp, causing slow leaks and cracks. If the molar ratio is large, the glass refining effect will be insufficient.

Li 0, Na 2 O and K 2 alkali metal oxides reduce the viscosity of the glass and

2 2 2

It is added for the purpose of improving the wettability. The content is preferably in the range of 0 to 10 mol%. If it exceeds 10 mol%, the thermal expansion coefficient of the glass becomes too large. In addition, since alkali components are easily eluted from the glass, when a fluorescent lamp is produced using the glass, the glass reacts with the phosphor or mercury to reduce the luminous flux of the fluorescent lamp. The content of each component is preferably Li 2 O: 0 to 5 mol%, Na 2 O: 0 to 8 mol%, and K 0: 0 to 12 mol%.

[0028] Alkaline earth metal oxides of MgO and CaO are added for the purpose of improving electrical insulation and chemical durability. The MgO content is preferably in the range of 0.5 to 5 mol%. The CaO content is preferably in the range of 0.5 to 10 mol%. If the MgO force is less than S0.5 mol% or CaO is less than 0.5 mol%, the above objective may not be achieved. On the other hand, when MgO is more than 5 mol% or CaO is more than 10 mol%, the glass tends to devitrify.

[0029] SrO and BaO are added for the purpose of improving the meltability of the glass and the bulb processability during the production of the fluorescent lamp. The content of SrO is preferably 0 to 8 mol%. The content of BaO is preferably 0 to 10 mol%. If SrO is more than 8 mol% or BaO is more than lOmol%, the glass tends to devitrify. CeO is added for the purpose of effectively absorbing ultraviolet rays and suppressing solarization. Its content is preferably in the range of 0.01 to 2 mol%. If the amount is less than 0.01 mol%, the above-mentioned purpose cannot be achieved. If the amount is more than 2 mol%, the glass is devitrified, making it difficult to produce a fluorescent lamp having a desired lamp luminous flux. Its content is particularly preferably in the range of 0.01 to lmol%.

[0030] Fe 0 is added for the purpose of obtaining an ultraviolet absorption effect. The content is preferably in the range of 0 to 0.2 mol%. If it exceeds 0.2 mol%, the transmittance in the visible region is lowered, and therefore the luminous flux of the fluorescent lamp is lowered.

SnO is added for the purpose of promoting the valence change of Ce ions from 4+ to 3+. Its content is preferably in the range of 0.01-5 mol%. If the amount is less than 0.01 mol%, the effect cannot be obtained. If the amount is more than 5 mol%, the mechanical strength of the glass decreases, and the yield decreases in the glass tube drawing process. The range of 0.1 to 3 mol% is particularly preferable.

[0031] The glass according to the present invention may contain other components as long as the content of each component is substantially within the above range as long as the composition does not deviate from the above range. Les. Examples of other components include ZrO, ZnO, P 2 O, TiO, and WO.

Conventionally, CeO is known as one of the fining agents. A clarification effect cannot be obtained unless a large amount of CeO is added. However, if a large amount is added to obtain a clarification effect, the problem of coloring the glass occurs. Therefore, even if only CeO is added as a clarifier

It is difficult to produce glass that is colorless and has few remaining bubbles.

[0032] Also, SnO is the same as CeO, which is known as one of the fining agents, and if it is not added in a large amount, the fining effect cannot be obtained. However, if a large amount is added to obtain a clarification effect, the problem of devitrification of the glass occurs. For this reason, even if SnO is added as a clarifier, it is difficult to produce a glass with no devitrification and few remaining bubbles.

(Description of manufacturing method of glass composition for lamp)

In the method for producing a glass composition for a lamp according to the present embodiment, first, a plurality of types of glass raw materials are prepared within the range of the composition of the glass composition for a lamp according to the present invention 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. for 5 to 8 hours in an air atmosphere to obtain a glass melt. At that time, do not perform stirring or publishing. Absent. 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 for a lamp. Furthermore, the glass tube is heat-processed to produce a glass bulb, and various lamps are produced.

[0033] It is not limited to the procedure of preparing a glass raw material to prepare a raw material mixture and then throwing it into the glass melting kiln, and dropping some glass raw materials into the glass melting kiln at a different timing from other glass raw materials. It is also possible to prepare the raw material mixture in a glass melting pot.

(Lamp description)

As an embodiment of the lamp according to the present invention, a straight tube type cold cathode fluorescent lamp will be described with reference to the drawings. FIG. 2 is a schematic diagram showing a main configuration of the cold cathode fluorescent lamp according to the present embodiment. The structure of the cold cathode fluorescent lamp 1 basically conforms to the structure of the cold cathode fluorescent lamp according to the prior art.

[0034] The glass bulb 2 of the cold cathode fluorescent lamp 1 is formed of the glass composition for a lamp according to the present embodiment, and has an outer diameter of about 4.0 mm, an inner diameter of about 3.0 mm, The length is about 730mm. The outer diameter, inner diameter and overall length of the glass bulb 2 are not limited to the above, but the outer diameter of the glass bulb 2 for the cold cathode fluorescent lamp 1 is 1.8 because it is desired that the tube diameter is small and the wall thickness is thin. The inner diameter is preferably 1.4;) to 6.0 (the inner diameter is 5.0) mm.

[0035] Both ends of the glass bulb 2 are hermetically sealed by the bead glass 3, respectively. In addition, at both ends of the glass bulb 2, lead wires 4 made of tungsten metal or Kovar alloy and having a diameter of about 0.8 mm are hermetically sealed so as to penetrate the bead glass 3. Then, a nickel or niobium cup-shaped electrode 5 whose surface is coated with an electron radioactive substance is attached to the end of each lead-in wire 4 on the inner side of the glass bulb 2.

[0036] On the inner surface of the glass bulb 2, a rare earth phosphor (Y 0: Eu ³⁺ , LaPO: Ce ³⁺ , Tb ³⁺ , BaMg Al 2 O ³ ) mixed with red, green and blue-green phosphors. : Eu ²⁺ , Mn ²⁺ )

2 3 4 2 16 27

A phosphor layer 6 is formed. The glass bulb 2 is filled with 0.8 to 2.5 mg of mercury (not shown) and a rare gas (not shown) such as xenon.

Although the straight tube type cold cathode fluorescent lamp 1 according to the present invention has been specifically described above based on the embodiment, the content of the present invention is not limited to the above embodiment.

[0037] (Explanation of experiment) A glass composition for a lamp according to the present embodiment shown in FIG. 1 and a glass composition for a lamp according to a comparative example shown in FIG. 3 were prepared, and their characteristics were evaluated and compared.

Each glass composition is prepared by weighing 17 g of the raw material mixture adjusted to the composition shown in the figure, placing it in a platinum crucible, heating and melting at 1500 ° C. for 3 hours in an electric furnace, and then taking it out from the electric furnace. The bottom was brought into contact with cold water and quenched to peel off the interface between the glass and the crucible.

[0038] The thermal expansion coefficient (f) and glass transition point were obtained by molding each glass composition into a cylindrical shape having a diameter of 5.0 mm and a length of 15 mm, and using a thermomechanical analyzer (manufactured by Rigaku, model number: TAS300 T MA8140C) was used to measure the average linear expansion coefficient in the temperature range of 30 to 380 ° C.

The number of bubbles was counted using image processing software for the number of bubbles confirmed in the central section of the glass composition at 120 mm ² and the plate thickness of 3 mm. Only bubbles with a diameter of 30 μπι or more were counted as bubbles.

[0039] The number of bubbles was cut into 120mm ² (longitudinal lOmm x width 12mm) and plate thickness 3mm at the center of the cross section of the glass composition, and then both sides of the glass were # 400, # 800, # 1000, # 1500, # 2000 Polished step by step, finished to a mirror surface, and made a glass sumnoire. The number of bubbles confirmed in the glass sample was counted using image processing software. Only bubbles with a diameter of 30 μπι or more were counted as bubbles.

[0040] In the remaining bubble determination, a bubble having more than 350 bubbles was judged as "X", and a bubble having less than 350 bubbles was judged as "O". This is because it has been confirmed that when a lamp is produced with a glass composition having more than 350 bubbles, a significant decrease in yield occurs.

Re-foaming during heat processing is when the glass composition is heat-processed and bubbles with a diameter of 30 / m or more in the overheated part are judged as “X” with re-foaming, and no re-foaming has occurred. Was determined to be “◯”.

[0041] The infrared transmittance was measured in a wavelength range of 2800 to 3800 cm- ¹ using a FT-IR (FTIR-8200, manufactured by Shimadzu Corporation) for a glass composition having a sample thickness of 2 mm and mirror polished on both sides. . When evaluating an actual bulb, the glass bulb was softened at a temperature of the glass bulb softening point + 20 ° C for 3 hours to soften the bulb to produce a glass plate having a thickness of 2 mm. The glass plate is then cut into a 15mm x 15mm square, 15mm x 15mm x 2mm thick A sample for evaluation was obtained. Both surfaces of the sample for evaluation were polished step by step to # 400, # 800, # 1000, # 1500, and # 2 000, and finished to a mirror surface.

[0042] Fig. 4 shows the measurement results. The infrared transmittance was performed for the purpose of evaluating the amount of water remaining in the glass composition. The water remaining in the glass composition is generated by the decomposition reaction of HBO, and a part of it is dissolved in the glass composition. If the amount of water dissolved in the glass composition is large, the water dissolved when the glass composition is heated is gasified and re-foaming occurs.

The amount of water in the glass composition can be confirmed by the minimum value of infrared transmittance in the vicinity of 3620 cm- ¹ , that is, the size of the absorption peak of OH— confirmed in the vicinity of 3620 cm- ¹ . Specifically, the smaller the minimum value of the infrared transmittance in the vicinity of 3620 cm- ¹ , the greater the amount of water remaining in the glass composition. 5, 3620Cm- ¹ to facilitate Verify minimum value of the infrared transmittance near is an enlarged view of a measurement result of the infrared transmittance in the wavelength range of 3600c m- ^¹ ~ 3800cm- ^1.

[0043] Comparative Examples:! To 5 have a relatively high infrared transmittance of 37.8 cm- ¹ near 7.8 to 8.0%. This is because H BO is not added and the remaining amount of water in the glass composition is small. However, Comparative Examples 1 to 5 cannot obtain the desired clarification effect because HBO is not added.

In addition, a large amount of bubbles remain in the glass composition. Therefore, it is not suitable for lamps.

In Comparative Examples 6 and 7, since the amount of HBO added is large, the amount of residual water in the glass composition is large, and the infrared transmittance near 3620 cm- ¹ is 2%. Thus, if there is a large amount of water remaining in the glass composition, re-foaming occurs during the heat treatment, which is not suitable for lamps.

[0044] In Comparative Example 8, both B 0 and H BO are added. However, since it is smaller than the mixing specific force of B 0 / H BO, the infrared ray transmittance in the vicinity of 3620 cm- ¹ where the residual amount of water in the glass composition is large is 2%. Thus, if the amount of water remaining in the glass composition is large, refoaming occurs during heat processing, which is not suitable for lamps.

In Comparative Example 9, both B 0 and H BO are added. However, since the mixing ratio of B 0 / H BO is large, the clarification effect is insufficient, and a large amount of bubbles remain in the glass composition, which is not suitable for lamps. [0045] In Examples 1 to 3, BO and H BO forces are added at a mixing ratio in the range of 1/3 to 1. For this reason, the glass composition has a high fining effect and few bubbles in the glass composition. Further, the infrared ray transmittance around 3620 cm- ¹ is in the range of 3.0 to 4.5%, and the residual amount of water in the glass composition is small, so that re-foaming is difficult to occur during heat processing. Therefore, it is suitable for lamps.

Industrial applicability

[0046] The method for producing a glass composition for a lamp, the glass composition for a lamp and a lamp according to the present invention can be widely used for all lamps. In particular, it is suitable for backlight cold cathode fluorescent lamps of transmissive liquid crystal display elements that require high-quality display such as liquid crystal TVs, personal computer displays, and in-vehicle liquid crystal panels. In addition, the method for producing a glass composition for a lamp, the glass composition for a lamp, and the lamp according to the present invention substantially do not contain environmentally hazardous substances such as arsenic, antimony, lead, etc. The power to respond to

Claims

The scope of the claims

[1] A melting step of melting a raw material mixture in which an oxide of a predetermined element and a hydroxide of the predetermined element are added in a molar ratio of oxide Z hydroxide = 1/3 to 1 into a glass state. In the melting step, the lamp is characterized in that the raw material mixture is heated so that a gas composed of at least one of H 0 or H is generated from the hydroxide by a decomposition reaction of the hydroxide. For producing a glass composition for use.

[2] The oxide and hydroxide are added to the raw material mixture so that the content of the predetermined element in the glass composition for a lamp is 8 to 17 mol% in terms of oxide. The method for producing a glass composition for a lamp according to claim 1.

[3] The hydroxide is added to the raw material mixture so that the content of the predetermined element in the glass composition for a lamp is 5 to: 10.5 mol% in terms of oxide conversion. The manufacturing method of the glass composition for lamps of Claim 2.

4. The method for producing a glass composition for a lamp according to claim 3, wherein the glass composition for a lamp is borosilicate glass, and the predetermined element is boron.

[5] The hydroxide is added to the raw material mixture so that the content of the predetermined element in the glass composition for a lamp is 5 to: 10.5 mol% in terms of oxide conversion. The manufacturing method of the glass composition for lamps of Claim 1.

6. The method for producing a glass composition for a lamp according to claim 1, wherein the glass composition for a lamp is borosilicate glass, and the predetermined element is boron.

[7] A glass composition for a lamp produced by the method for producing a glass composition for a lamp according to claim 1,

A glass composition for a lamp, characterized in that a minimum value of infrared transmittance in the wavelength region of 3620 cm- ¹ is 3.0 to 4.5% at a sample thickness of 2 mm.

[8] 30 to 380 ° coefficient of thermal expansion C (shed) lamp glass composition according to claim 7, feature that it is a ^{34 X 10- 7 / K~43 X 10-} 7 / Κ .

[9] 30 to 380 thermal expansion coefficient in ° C (alpha) is the lamp glass composition according to claim 7, feature that it is a ^{43 X 10- 7 / Κ~55 X 10-} 7 / Κ .

[10] A glass for a lamp produced by the method for producing a glass composition for a lamp according to claim 4. A composition comprising:

[11] 30 to 380 thermal expansion coefficient in ° C (shed) lamp glass composition according to claim 10, feature that it is a ^{34 X 10- 7 / K~43 X 10-} 7 / K .

[12] 30 to 380 ° thermal expansion coefficient (ratio) of C lamp glass composition according to claim 10, feature that it is a ^{43 X 10- 7 / K~55 X 10-} 7 / Κ .

[13] A lamp comprising the glass bulb formed of the glass composition for a lamp according to claim 7.

[14] A lamp comprising the glass bulb formed of the glass composition for a lamp according to [10].