JP2007012397A - Funnel for cathode-ray tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a funnel for cathode-ray tube capable of suppressing rise of strain point and deterioration of coefficient of thermal expansion of glass, even if the content of Al<SB>2</SB>O<SB>3</SB>in the glass is large. <P>SOLUTION: The funnel for cathode-ray tube is made of lead-contained glass which has a PbO content of 10-30 wt% and an X-ray absorption coefficient of 40 cm<SP>-1</SP>or more at 0.6 Å. The lead-contained glass contains as an essential component Al<SB>2</SB>O<SB>3</SB>, MgO, CaO, SrO, BaO, and ZnO, and the Al<SB>2</SB>O<SB>3</SB>content is more than 5 to 10 wt%, and the value of (MgO+CaO+SrO+BaO+ZnO)/Al<SB>2</SB>O<SB>3</SB>is 0.60-1.60. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a funnel for a cathode ray tube.

  The cathode ray tube bulb includes a panel on which an image is projected, a tubular neck on which an electron gun is mounted, and a funnel-shaped funnel connecting the panel and the neck. The electron beam emitted from the electron gun causes the phosphor provided on the inner surface of the panel to emit light and display an image on the panel. At this time, braking X-rays are generated in the tube, and this leaks out of the tube through the envelope. In order to adversely affect the human body, this type of envelope is required to have a high X-ray absorption capability.

Therefore, for example, lead glass containing 10 to 30% by mass of PbO having a high X-ray absorption ability and having an X-ray absorption coefficient of 0.6 cm or more at 40 cm ⁻¹ or more is used for the funnel. (See Patent Documents 1 and 2)
JP-A-8-31342 JP 2000-86277 A

By the way, each member constituting the cathode ray tube bulb is polished. For example, in the case of a cathode ray tube panel, a portion where an image is projected and the seal edge portion with the cathode ray tube funnel are polished, and in the case of a cathode ray tube funnel, the seal edge portion with the cathode ray tube panel is polished. Usually, such polishing is performed by supplying and sliding an abrasive mainly composed of alumina (Al ₂ O ₃ ) mixed with water to form a slurry between glass and a polishing platen. Is called.

  Thus, in the manufacturing process of the cathode ray tube bulb, since there is a polishing process using alumina, a large amount of polishing sludge mainly composed of alumina is generated. Polishing sludge generated in the polishing process may be landfilled as industrial waste after dehydration.

  However, in recent years, it has been difficult to secure an industrial waste disposal site, and it has become difficult to dispose of waste, and the processing cost has also increased. In addition, from the viewpoint of preventing environmental pollution, there is a strong demand for reducing waste and reusing resources. Under such circumstances, it has become an important issue how to recycle the high-alumina-concentration polishing sludge generated when manufacturing a cathode ray tube bulb.

As a method for recycling the polishing sludge, it is conceivable to use it as a raw material for Al ₂ O ₃ contained in the funnel glass. However, with the content of Al ₂ O ₃ contained in the current funnel glass, the amount of polishing sludge generated is greater than the amount of polishing sludge used as a raw material, and therefore polishing sludge cannot be completely recycled. .

If the content of Al ₂ O ₃ in the funnel glass is increased in order to completely recycle the polishing sludge, the strain point of the glass increases or the thermal expansion coefficient decreases. As a result, there arises a problem that the stress generated when sealing the panel or the neck becomes too large and is damaged when the cathode ray tube bulb is manufactured.

An object of the present invention is to provide a funnel for a cathode ray tube capable of suppressing an increase in strain point and a decrease in thermal expansion coefficient of glass even when the Al ₂ O ₃ content in the glass is large.

As a result of repeating various experiments, the present inventors have determined that the value of (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ falls within a specific range even when the content of Al ₂ O ₃ in the glass is large. It is to find and propose that the increase in the points can be suppressed.

That is, the funnel for a cathode ray tube according to the present invention is the funnel for a cathode ray tube comprising a lead-containing glass having a PbO content of 10 to 30% by mass and an X-ray absorption coefficient at 0.6 cm of 40 cm ⁻¹ or more. The glass contains Al ₂ O ₃ , MgO, CaO, SrO, BaO, ZnO as essential components, the Al ₂ O ₃ content is more than 5 to 10% by mass, and the value of (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ is 0. It is 6-1.6.

The funnel for a cathode ray tube of the present invention can recycle the polishing sludge because it can suppress an increase in the strain point of the glass and a decrease in the thermal expansion coefficient even when the Al ₂ O ₃ content in the glass increases. . Further, it is possible to prevent the cathode ray tube bulb from being damaged by suppressing the stress generated at the time of sealing with the panel or the neck within an allowable range. Therefore, it is suitable as a funnel for a cathode ray tube.

Generally, when the content of Al ₂ O _{3 in} the glass increases, the strain point of the glass increases and the thermal expansion coefficient decreases. In particular, in the case of funnels, the panel or neck must be sealed, so if the strain point of the glass rises or the thermal expansion coefficient falls, stress exceeding the allowable range will not occur, and as a cathode ray tube bulb The strength of can not be maintained.

Therefore, the funnel for a cathode ray tube of the present invention is a component that increases the thermal expansion coefficient, MgO, CaO, SrO, BaO, ZnO, in order to suppress a decrease in the thermal expansion coefficient due to an increase in the content of Al ₂ O _{3 in} the glass. Are each included as an essential component. In addition, since MgO, CaO, SrO, BaO, and ZnO are components that increase the strain point of glass, in order to bring the strain point and thermal expansion coefficient of glass into desired ranges, (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ Is adjusted to 0.6 to 1.6. In this way, even if the content of Al ₂ O ₃ in the glass is increased in order to recycle the polishing sludge, an increase in the strain point of the glass and a decrease in the thermal expansion coefficient can be suppressed. Therefore, when sealing with a panel or a neck, stress exceeding an allowable range is hardly generated, and the strength as a cathode ray tube bulb can be maintained.

  The cathode ray tube funnel of the present invention is preferably made of glass having a strain point of 437 to 453 ° C. A preferable range of the strain point is 438 to 452 ° C.

Moreover, it is desirable that the glass has a thermal expansion coefficient of 98 to 103 × 10 ⁻⁷ / ° C. A preferable range of the thermal expansion coefficient is 99 to 102 × 10 ⁻⁷ / ° C.

  When the strain point and the thermal expansion coefficient are within the above ranges, stress exceeding an allowable range is less likely to occur when sealing the panel or neck, and the strength as a cathode ray tube bulb can be maintained.

The funnel for a cathode ray tube of the present invention is preferably made of glass having an X-ray absorption coefficient of 40 cm ⁻¹ or more at a wavelength of 0.6 mm. This is because if the X-ray absorption coefficient is smaller than 40 cm ^{−1, the} amount of X-ray transmission increases so much that the human body may be adversely affected. In addition, what is necessary is just to make PbO contain 10 mass% or more in glass, in order to raise an X-ray absorption coefficient.

Furthermore, the specific composition that can be used for the lead-containing glass used in the funnel for a cathode ray tube of the present invention is, by mass percentage, SiO ₂ 43 to 55%, Al ₂ O ₃ more than 5 to 10%, PbO 10 to 30%, MgO 0.1-5%, CaO 0.1-6%, SrO 0.1-9%, BaO 0.1-9%, ZnO 0.1-5%, Na ₂ O 3-9%, K ₂ A range containing a composition of O 3-11%, ZrO ₂ 0-3%, Sb ₂ O ₃ 0-2%, and a value of (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ being 0.6-1.6. May be selected as appropriate.

  The reason for limiting the glass composition as described above in the present invention is as follows.

SiO ₂ is a glass network former. Its content is 43-55%, preferably 43.5-54.5%. When the content of SiO ₂ increases, the high temperature viscosity of the glass increases and melting becomes difficult. In addition, the strain point of the glass tends to increase or the thermal expansion coefficient tends to be small, and when sealing with a panel or neck, stress exceeding an allowable range is generated, making it difficult to maintain the strength as a cathode ray tube bulb. . On the other hand, when the content is reduced, the viscosity of the glass is lowered and molding becomes difficult. Also, the strain point of glass tends to decrease or the coefficient of thermal expansion tends to increase, and when sealing with a panel or neck, stress exceeding the allowable range occurs, making it difficult to maintain the strength as a cathode ray tube bulb. .

Al ₂ O _{3 is} also a component that becomes a glass network former. The content is more than 5 to 10%, preferably 6 to 9%, more preferably 6 to 8%. When the content of Al ₂ O ₃ increases, the high temperature viscosity of the glass increases and melting becomes difficult. In addition, the strain point of the glass tends to increase or the thermal expansion coefficient tends to be small, and when sealing with a panel or neck, stress exceeding an allowable range is generated, making it difficult to maintain the strength as a cathode ray tube bulb. . On the other hand, when the content is decreased, the amount of polishing sludge used is decreased, which is not preferable.

  PbO is a component that increases the X-ray absorption coefficient of glass. Its content is 10-30%, preferably 15-27%. When the content of PbO increases, the viscosity of the glass becomes too low and molding becomes difficult. On the other hand, when the content decreases, it becomes difficult to obtain a sufficient X-ray absorption coefficient.

  MgO is a component that increases the strain point and thermal expansion coefficient of glass. Its content is 0.1 to 5%, preferably 0.1 to 4.5%. When the content of MgO increases, the strain point of the glass becomes too high, and stress exceeding an allowable range is generated when sealing with a panel or a neck, making it difficult to maintain the strength as a cathode ray tube bulb. Further, the glass tends to be devitrified, making it difficult to mold. On the other hand, if the content is reduced, the strain point and thermal expansion coefficient of the glass become too low, and stress exceeding the allowable range is generated when sealing with the panel or neck, making it difficult to maintain the strength as a cathode ray tube bulb. Become.

  CaO, like MgO, is a component that increases the strain point and thermal expansion coefficient of glass. Its content is 0.1 to 6%, preferably 0.1 to 5%. When the content of CaO increases, the strain point of the glass becomes too high, and stress exceeding an allowable range is generated when sealing with a panel or a neck, and it becomes difficult to maintain the strength as a cathode ray tube bulb. Further, the glass tends to be devitrified, making it difficult to mold. On the other hand, if the content is reduced, the strain point and thermal expansion coefficient of the glass become too low, and stress exceeding the allowable range is generated when sealing with the panel or neck, making it difficult to maintain the strength as a cathode ray tube bulb. Become.

  SrO is a component that increases the strain point and thermal expansion coefficient of glass. Moreover, it is also a component which improves X-ray absorption ability. Its content is 0.1 to 9%, preferably 0.1 to 7%. When the SrO content increases, the strain point of the glass becomes too high, and stress exceeding an allowable range is generated when sealing with a panel or a neck, and it becomes difficult to maintain the strength as a cathode ray tube bulb. Further, the glass tends to be devitrified, making it difficult to mold. On the other hand, if the content is reduced, the strain point and thermal expansion coefficient of the glass become too low, and stress exceeding the allowable range is generated when sealing with the panel or neck, making it difficult to maintain the strength as a cathode ray tube bulb. Become. In addition, it is difficult to obtain a sufficient X-ray absorption coefficient.

  BaO, like SrO, is a component that increases the strain point and thermal expansion coefficient of glass. Moreover, it is also a component which improves X-ray absorption ability. Its content is 0.1 to 9%, preferably 0.1 to 7%. When the content of BaO increases, the strain point of the glass becomes too high, and stress exceeding an allowable range is generated when sealing with a panel or a neck, and it becomes difficult to maintain the strength as a cathode ray tube bulb. Further, the glass tends to be devitrified, making it difficult to mold. On the other hand, if the content is reduced, the strain point and thermal expansion coefficient of the glass become too low, and stress exceeding the allowable range is generated when sealing with the panel or neck, making it difficult to maintain the strength as a cathode ray tube bulb. Become. In addition, it is difficult to obtain a sufficient X-ray absorption coefficient.

  ZnO is a component that increases the strain point and thermal expansion coefficient of glass. Moreover, it is also a component which improves X-ray absorption ability. Its content is 0.1 to 5%, preferably 0.1 to 4%. When the content of ZnO increases, the strain point of the glass becomes too high, and stress exceeding an allowable range is generated when sealing with a panel or a neck, and it becomes difficult to maintain the strength as a cathode ray tube bulb. Moreover, there exists a tendency for the deposit resulting from ZnO to precipitate by volatilization and aggregation. On the other hand, if the content is reduced, the strain point and thermal expansion coefficient of the glass become too low, and stress exceeding the allowable range is generated when sealing with the panel or neck, making it difficult to maintain the strength as a cathode ray tube bulb. Become. In addition, it is difficult to obtain a sufficient X-ray absorption coefficient.

In a composition system containing Al ₂ O ₃ in excess of 5 to 10%, the value of (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ is set to 0.6 to suppress the increase in the strain point and the decrease in the thermal expansion coefficient of the glass. It is important to adjust to 1.6, and a preferable range is 0.6 to 1.3, more preferably 0.62 to 1.1, and still more preferably 0.64 to 1.08. When this value is increased, the strain point of the glass becomes too high, and when the panel or neck is sealed, stress exceeding an allowable range is generated, and it is difficult to maintain the strength as a cathode ray tube bulb. On the other hand, if this value is reduced, the strain point and thermal expansion coefficient of the glass become too low, and stress exceeding the allowable range is generated when sealing with a panel or neck, making it difficult to maintain the strength as a cathode ray tube bulb. Become.

Na ₂ O is a component that adjusts the thermal expansion coefficient and viscosity. Its content is 3-9%, preferably 4-8%. When the Na ₂ O content increases, the thermal expansion coefficient tends to increase, and when sealing with a panel or neck, stress exceeding an allowable range is generated, and it is difficult to maintain the strength as a cathode ray tube bulb. On the other hand, when the content is reduced, the thermal expansion coefficient tends to be low, and when sealing with a panel or neck, stress exceeding an allowable range is generated, and it is difficult to maintain the strength as a cathode ray tube bulb. Moreover, the high temperature viscosity of glass becomes high and melting becomes difficult.

K ₂ O, like Na ₂ O, is a component that adjusts the thermal expansion coefficient and viscosity. Its content is 4-11%, preferably 5-10%. When the content of K ₂ O increases, the coefficient of thermal expansion tends to increase. When sealing with a panel or neck, stress exceeding an allowable range is generated, and it is difficult to maintain the strength as a cathode ray tube bulb. On the other hand, when the content is reduced, the thermal expansion coefficient tends to be low, and when sealing with a panel or neck, stress exceeding an allowable range is generated, and it is difficult to maintain the strength as a cathode ray tube bulb. Moreover, the high temperature viscosity of glass becomes high and melting becomes difficult.

ZrO ₂ is a component that enhances the X-ray absorption ability. Its content is 0-3%, preferably 0-2.5%. When the content of ZrO ₂ increases, the glass tends to be devitrified, and molding becomes difficult.

Sb ₂ O ₃ is a component that acts as a fining agent. Its content is 0-2%, preferably 0.01-1%. When the content of Sb ₂ O ₃ is increased, the glass tends to be devitrified and molding becomes difficult. Moreover, even if it contains more than predetermined amount, the effect is not acquired notably and raw material cost becomes high.

In addition to the above components, it is possible to add other components as long as the properties of the glass are not impaired. For example, P ₂ O ₅ may be added up to 1% as a component for suppressing devitrification. .

  The cathode ray tube funnel of the present invention is obtained by melting a raw material batch prepared so as to have the above composition range at about 1500 ° C. to vitrify, then forming a gob from this molten glass and supplying it into the mold It can be obtained by press molding.

  Hereinafter, the funnel for a cathode ray tube of the present invention will be described in detail based on examples.

  Tables 1 and 2 show examples (samples Nos. 1 to 7) and comparative examples (samples Nos. 8 to 11) of the present invention. Sample No. Reference numeral 11 denotes a current funnel for a cathode ray tube.

  Each sample in the table was prepared as follows.

  First, a raw material batch is prepared using polishing sludge and glass raw material so as to have the glass composition in the table. Next, the prepared raw material batch was put in a platinum crucible and melted at about 1500 ° C. for 4 hours. In order to obtain homogeneous glass, defoaming was carried out by stirring for 3 minutes using a platinum stirring rod in the middle. Thereafter, the molten glass was put into a mold, formed into a 14-inch cathode ray tube funnel, and then slowly cooled. About each obtained sample, the strain point, the thermal expansion coefficient, and the X-ray absorption coefficient were measured. The results are shown in the table.

As can be seen from the table, the sample No. Each of the samples 1 to 7 had a strain point of 446 to 452 ° C. and a thermal expansion coefficient of 100 to 101 × 10 ⁻⁷ / ° C., which was equivalent to the current funnel. Furthermore, the X-ray absorption coefficient was as high as 66 cm ⁻¹ .

On the other hand, sample No. which is a comparative example. No. 8 has a strain point as low as 436 ° C. and a thermal expansion coefficient as low as 97 × 10 ⁻⁷ / ° C. Nos. 9 and 10 have a high strain point of 456 ° C. or higher. No. 10 has a low thermal expansion coefficient of 97 × 10 ⁻⁷ / ° C. Therefore, when sealing with a panel or a neck, it is expected that stress exceeding the allowable range is generated.

  The strain point was measured based on ASTM C336-71.

  Moreover, about the thermal expansion coefficient, the cylindrical sample of diameter 5.0mm and length 20mm was produced, and the average thermal expansion coefficient in 30-380 degreeC was measured with the dilatometer.

  The X-ray absorption coefficient was obtained by calculating the absorption coefficient for a wavelength of 0.6 mm based on the glass composition and density.

Claims (4)

In a funnel for a cathode ray tube comprising a lead-containing glass having a PbO content of 10 to 30% by mass and an X-ray absorption coefficient at 0.6 cm of 40 cm ⁻¹ or more, the lead-containing glass comprises Al ₂ O ₃ , MgO, CaO, SrO, BaO, ZnO is contained as an essential component, Al ₂ O ₃ content is more than 5 to 10% by mass, and (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ is 0.60 to 1.60. A funnel for a cathode ray tube. Lead-containing glass, by mass _{percentage, SiO 2 43~55%, Al 2} O 3 5 super ~10%, PbO 10~30%, 0.1~5 % MgO, CaO 0.1~6%, SrO 0 .1~9%, BaO 0.1~9%, 0.1~5 % ZnO, Na 2 O 3~9%, K 2 O 3~11%, ZrO 2 0~3%, Sb 2 O 3 0 _{2. The} funnel for a cathode ray tube according to claim 1, comprising a composition of ˜2% and a value of (MgO + CaO + SrO + BaO + ZnO) / Al ₂ O ₃ is 0.60 to 1.60.   The funnel for a cathode ray tube according to claim 1 or 2, comprising a lead-containing glass having a strain point of 437 to 453 ° C. The funnel for a cathode ray tube according to any one of claims 1 to 3, wherein the funnel is made of lead-containing glass having a thermal expansion coefficient of 98 to 102 x ^10-7 / ° C at 30 to 380 ° C.