JP2002060242A - Funnel for cathode ray tube and cathode ray tube using the same - Google Patents

Abstract

[PROBLEMS] To reduce the weight of a CRT as a whole without impairing the impact resistance, pressure resistance, etc. of a funnel. A cathode-ray tube funnel of the present invention, in weight percent, 45% to 60% of SiO _2, 0.1% to 15% of _{Al 2 O 3, 5% ~20} % of Na ₂ O, 15% It is obtained by chemically strengthening glass containing ３０30% of PbO. A cathode ray tube using such a funnel for a cathode ray tube is also provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-strength funnel for a cathode ray tube and a cathode ray tube using the same.

[0002]

2. Description of the Related Art In recent years, the size of a television monitor has been increased, and the weight of a cathode ray tube (hereinafter, simply referred to as "CRT") has been remarkably increased. The greatest cause of this weight increase is the weight of the glass. The glass member occupies about 60% of the entire weight of the CRT set.

A CRT glass member is roughly divided into a panel for projecting a screen, a funnel on the back, and a neck of an electron gun. About 60% of the glass weight is for panels and about 30% is for funnels.

For example, a 36-inch CRT panel has a thickness of 20 mm or more, weighs about 40 kg, and a television set weighs about 70 kg. For this reason, particularly in a Japanese residential environment, not only is it difficult to install a large-screen TV set, but also a large amount of energy and cost are required for delivery and transportation for transferring such a heavy CRT.

[0005] Among such CRT glass members, a conventional funnel is made of PbO to obtain a desired X-ray absorption coefficient.
Is used. Further, a CRT having a vacuum inside needs to have sufficient glass strength, and the funnel has a rounded shape so that the load is not concentrated on a part.

[0006]

However, the bending strength of this type of funnel glass is about 100 MPa.
In order to secure impact resistance, the thickness of the glass should be 3 mm to 1 mm.
It must be as thick as 0 mm. This increases the weight of the funnel, making it difficult to reduce the weight of the CRT.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems. That is, the funnel for a cathode ray tube of the present invention is 45% to 6% by weight.
0% SiO _2, 0.1% ~15% of Al ₂ O _3, 5% ~
It is obtained by chemically strengthening a glass containing 20% of Na ₂ O and 15% to 30% of PbO. A cathode ray tube using such a funnel for a cathode ray tube is also provided.

According to the present invention, as a funnel for a cathode ray tube, while obtaining a sufficient X-ray absorption coefficient, a deep stress-strain layer can be obtained by chemical strengthening to have sufficient strength.

[0009]

Embodiments of the present invention will be described below. The CRT funnel according to the present embodiment includes:
Mainly from the viewpoint of reducing the weight of the CRT, it is characterized in that desired characteristics can be ensured even when the thickness is reduced.

The CRT funnel according to the present embodiment comprises:
45% -60% SiO by weight _Two, 0.1% to 15
% Al_TwoO_Three5% -20% Na_TwoO, 15% -30
% PbO-containing glass obtained by chemical strengthening
It is. This chemical strengthening also causes ion exchange on the surface.
It is done by doing.

[0011] In such a CRT funnel, PbO is contained in the glass in an amount of 15% to 30%.
An X-ray absorption coefficient of at least cm can be obtained. Further, glass having excellent melting properties and chemical strengthening properties can be constituted by the above composition.

In addition to the above composition, Li ₂ O, K ₂ O,
MgO, CaO, SrO, BaO, ZnO, TiO ₂ ,
At least one or a plurality of glass components selected from the group consisting of ZrO ₂ , Sb ₂ O ₃ , and CeO ₂ may be used as optional components.

By including these optional components, the ion exchange efficiency is improved, the thermal expansion coefficient, the glass transition point, the strain point,
Adjustment of the softening point, etc., adjustment of the X-ray absorption coefficient, improvement of the glass meltability, viscosity of the molten glass, chemical durability, and electrical properties can be achieved.

The glass of the funnel for a CRT according to the present embodiment has a bending strength about four times that of the conventional untempered glass. Therefore, the use of the CRT funnel of the present embodiment not only significantly improves the pressure resistance of the funnel, but also makes it possible to reduce the thickness and weight of the funnel.

The chemically strengthened glass forming the stress-strain layer by ion exchange on the surface has the advantage that high strength can be obtained even with a thin plate. Also, unlike physical enhancement,
Even with a glass having a complicated shape such as a funnel, a stress-strain layer on the surface can be uniformly formed.

Further, in the present embodiment, even if the same strength is obtained, the thickness of the funnel can be reduced as compared with the conventional case, and the thermal shock resistance can be improved. Therefore, for example, at the time of frit joining between the panel and the funnel, the heating or cooling rate can be increased, so that the production tact can be improved and the production cost can be reduced.

The glass used in the CRT funnel of the present embodiment has an X-ray absorption coefficient of 62 / cm or more,
In addition, an alkali component is appropriately contained so that a stress-strain layer can be obtained by ion exchange.

Here, various components and a preferable composition range of the glass applied in the present embodiment will be described.

SiO ₂ is a basic component of glass.
%, The chemical durability deteriorates and the glass is apt to be devitrified. On the other hand, if it exceeds 60%, the viscosity of the glass becomes high and melting becomes difficult. Therefore, the content of SiO ₂ is 45% to 60%, preferably 50% to 55%.

Al ₂ O ₃ is a component for improving the devitrification resistance, chemical durability and ion exchange efficiency of glass.
If it is less than 1%, these effects are not obtained, and if it exceeds 15%, devitrification tends to occur. Therefore, the content of Al ₂ O ₃ is 0.1% to 15%, preferably 5% to 10%.

Na ₂ O improves the meltability of the glass and forms a stress-strain layer on the glass surface by being ion-exchanged mainly with K ions during the ion exchange treatment at the glass surface layer, thereby strengthening the glass. It is a component for performing. Na
_{If 2} O is less than 5%, the meltability deteriorates, and if it exceeds 15%, the devitrification resistance and the chemical durability decrease. Therefore, Na
The content of ₂ O is 5% to 15%, preferably 5% to 10%.
%.

PbO is a component having a large X-ray absorption coefficient and improving the melting property of glass, but if it is less than 15%, the X-ray absorption coefficient will be small, and if it exceeds 30%, devitrification resistance and bending strength will be exceeded. Decrease. Therefore, the content of PbO is 15% to 30%, preferably 20% to 25%.

Li ₂ O, K ₂ O, MgO, CaO, Sr
_{O, BaO, ZnO, TiO 2} , ZrO 2, Sb 2 O 3, C
eO ₂ is obtained by melting glass, glass viscosity, devitrification resistance, X
It can be appropriately contained for the purpose of improving the linear absorption coefficient, the ion exchange efficiency, the thermal expansion coefficient, the glass transition point, the strain point, the softening point, and the like, and for the purpose of fining.

Preferably, Li ₂ O + K ₂ O is 5% to 10%.
%, MgO + CaO + SrO + BaO + ZnO is 5% or more
10%, TiO ₂ + ZrO ₂ is 0% to 5%, and Sb ₂ O ₃ is 0.1% to 0.5%.

The ion exchange is performed by immersing the glass in an alkali molten salt. The composition of the molten salt used in the ion exchange and the processing temperature are appropriately selected according to the composition of the glass to be subjected to the ion exchange. Then, after holding for a predetermined time, the glass is taken out and washed.

Whether or not the glass is chemically strengthened can be determined by examining the distribution of metal ions contained in the vicinity of the glass surface. That is, the depth distribution of a metal ion having a larger ionic radius (for example, an alkali metal ion) and a depth distribution of a metal ion having a smaller ionic radius (for example, an alkali metal ion) are examined.

The ratio of (density of metal ions having a larger ionic radius) / (density of metal ions having a smaller ionic radius) is larger than that of a deep portion of glass (for example, a portion having a depth of half the thickness of glass). If the portion closer to is larger and the bending strength is higher, it can be understood that chemical strengthening by ion exchange has been performed.

Next, examples and comparative examples of the CRT funnel of the present invention will be described. FIG. 1 is a diagram illustrating Examples 1 to 6 and Comparative Example 1.

(Examples 1 to 6, Comparative Example 1) Formulation in which raw materials such as oxides, hydroxides, carbonates, nitrates, chlorides and sulfates were weighed and mixed so as to have the composition shown in FIG. The raw materials were placed in a heat-resistant container such as a platinum crucible, heated to 1400 ° C., melted, stirred, homogenized and clarified, and then poured into a mold. After the glass was solidified, it was transferred to an electric furnace heated near the annealing point of the glass, and gradually cooled to room temperature.

A test piece was prepared from the obtained glass block and subjected to ion exchange. Ion exchange is 380
The glass sample was immersed in a potassium nitrate molten salt maintained at a temperature of from ℃ to 460 ° C for a predetermined time, and then taken out and washed.

FIG. 1 shows various measurement data of various glass samples (Examples 1 to 6, Comparative Example) corresponding to the glass composition.

The X-ray absorption coefficient is as follows:
m X-rays are incident, the transmitted dose at a position 50 mm away from the opposite surface to the incident is measured, and the absorption coefficient is calculated. The bending strength of the ion-exchanged sample was measured according to JIS-
It was measured according to the three-point bending test of R1601.

The glass samples of Examples 1 to 6 all have a bending strength of 250 MPa or more, and have a sufficient strength and an X-ray absorption coefficient of 60 / cm or more.
Thereby, while having an X-ray absorption coefficient necessary for CRT, a sufficient intensity can be obtained.

On the other hand, in the glass sample of Comparative Example 1,
Although the flexural strength has a high value of 300 MPa, the X-ray absorption coefficient is as low as 28 / cm, so that it cannot be used as a funnel for a cathode ray tube.

[0035]

As described above, the present invention has the following effects. That is, the impact resistance can be improved by realizing the high strength of the funnel for a cathode ray tube, and the weight can be reduced by reducing the glass thickness by utilizing the improvement of the pressure resistance. This makes it possible to reduce the weight of the entire cathode ray tube. In addition, it becomes possible to improve the thermal shock resistance of the glass in the frit sealing step to improve the productivity of the cathode ray tube.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example and a comparative example.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masataka Mitoku 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Masamichi Okada 6-35, Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Mitsuo Hashimoto 6-7-35 Kita Shinagawa, Shinagawa-ku, Tokyo Sony Corporation (72) Inventor Tadashi Watanabe 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo Hoya Co., Ltd. (72) Inventor Yoichi Hachiya 2-7-5 Nakaochiai, Shinjuku-ku, Tokyo F-term in Hoya Corporation (reference) 4G059 AA07 AC16 HB03 HB14 4G062 AA03 BB01 BB04 DA05 DA06 DB02 DB03 DB04 DC01 DD01 DE01 DE02 DF04 EA02 EB03 EB04 EC01 EC02 EC03 ED01 ED02 ED03 EE01 EE02 EE03 EF01 EF02 EF03 EG01 EG02 EG03 FA01 FA10 FB01 FB02 FC01 FC02 FC03 FD01 FE01 FF01 FG01 FH01 FJ01 FK10 FL01 FL02 GA01 GB01 GC01 GD01 GE01 HH01 HH03 HH05 HH07 HH09 HH11 HH13 HH15 HH17 HH20 JJ01 JJ03 JJ05 JJ07 JJ10 KK01 KK03 KK05 KK07 KK10 MM25 NN14 NN33 5C032 AA02 BB10

Claims (5)

[Claims] 1. A weight%, 45% to 60% of SiO _2, 0.1% to 15% of _{Al 2 O 3, 5% ~20} % of Na ₂ O, 15% to 30% of PbO, the A funnel for a cathode ray tube, which is obtained by chemically strengthening glass contained therein. 2. The funnel for a cathode ray tube according to claim 1, wherein the chemical strengthening is to form a stress-strain layer on the surface of the glass by ion exchange. 3. The glass has an X-ray absorption coefficient of 62 / c.
2. The funnel for a cathode ray tube according to claim 1, wherein the length is at least m. 4. In addition to the components constituting the glass panel for a cathode ray tube according to claim 1, Li ₂ O,
K ₂ O, MgO, CaO, SrO, BaO, ZnO, T
A funnel for a cathode ray tube comprising at least one or a plurality of glass components selected from the group consisting of iO ₂ , ZrO ₂ , Sb ₂ O ₃ , and CeO ₂ . 5. A cathode ray tube using the funnel for a cathode ray tube according to claim 1. Description: