JP2003051273A - Glass bulb for color cathode-ray tube, and color cathode- ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a glass bulb for cathode-ray tubes, which can attain lightweight and/or a flat face part through chemical strengthening processing, and can reduce the stresses generated in its sealing part, and moreover to provide a cathode-ray tube which is highly safe using the glass bulb. SOLUTION: This glass bulb for cathode-ray tubes has a panel which has been added with compression stress σc , which is 50 MPa<=|σc |<=250 MPa, to at least either side of a short axis end part or a long axis end part of the outside surface of the face part by the chemical strengthening method, and has the relation t=(tc +tmax )/2 for the average flesh thickness of the face part, which is expressed with a center part flesh thickness tc of the face part and a maximum flesh thickness tmax , and has a flesh thickness tse of the seal edge part of t/tse <=1.4. Furthermore, the glass valve for cathode-ray tubes has the maximum value σVTmax of tensile stresses generated in the face part by making the inside into a vacuum is 20 MPa<=σVTmax <200 MPa.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glass bulb for a color cathode ray tube and a color cathode ray tube used for a television broadcast receiver (hereinafter referred to as a television), a display for a computer and the like.

[0002]

2. Description of the Related Art First, the structure of a color cathode ray tube will be described with reference to the drawings. 1 is a partial cross-sectional view of the entire color cathode ray tube, and FIG. 2 is an enlarged view of the vicinity S of the sealing portion in FIG. In the present invention, the term "cathode ray tube" means a color cathode ray tube unless otherwise specified.

The envelope of the cathode ray tube 1 basically comprises a panel 3 for displaying an image, a funnel-shaped funnel 4 hermetically joined to the panel 3, and a neck 5 for housing an electron gun 17. It is composed of a glass bulb 2. The panel 3 has a substantially rectangular face portion 7 forming an image display surface, and a blend R from the peripheral portion of the face portion 7.
Skirt portion 6 extending substantially vertically through the portion 9.
Composed of and.

An explosion-proof reinforcing band 8 is wound around the outer periphery of the skirt portion 6 for maintaining the panel strength and preventing scattering at the time of breakage. The electron gun 1 is provided on the inner surface side of the face portion 7.
A fluorescent film 12 which emits fluorescence by an electron beam impact from 7.
An aluminum film 13 for reflecting fluorescence emitted from the fluorescent film 12 behind the cathode ray tube (on the funnel 4 side) to the front (on the face portion 7 side) is laminated, and a shadow mask 14 for defining an electron beam irradiation position is provided. To be The shadow mask 14 is fixed to the inner surface of the skirt portion 6 by stud pins 15. In the figure, A indicates a tube axis connecting the center axis of the neck 5 and the center of the panel 3.

As shown in FIG. 2, such a panel 3 is hermetically joined to the seal edge portion 16 'of the funnel 4 by a seal material such as solder glass provided on the seal edge portion 16 which is an end portion of the skirt portion 6. The sealing portion 10 is formed.

The glass bulb 2 for a cathode ray tube having the above structure is
Since it is used as a vacuum container, atmospheric pressure acts on the outer surface, but due to an asymmetrical shape different from the spherical shell, it is in an unstable deformed state, and stress acts on a relatively wide range (hereinafter, glass bulb). The stress generated by applying a vacuum inside is called vacuum stress). When a high tensile vacuum stress is applied to the outer surface, delayed fracture due to the action of moisture in the atmosphere may occur, which may cause a decrease in safety and reliability.

The face portion 7, which is a portion for displaying an image, has the lowest flatness because it has the highest flatness in the cathode ray tube and is most deformed when the inside of the cathode ray tube is decompressed and the atmospheric pressure is applied. . Further, since the face portion 7 is supported by the blend R portion 9 having high rigidity, a high tensile vacuum stress is generated in the vicinity of the blend R portion 9 as the face portion 7 is deformed. Further, since the deformation of the face portion 7 acts as a force for deforming the skirt portion 6 to the outside via the blend R portion 9, a high tensile vacuum stress is also generated in the sealing portion 10.

However, in the case where the sealing portion hermetically joined by the sealing material has the lowest allowable value for the tensile vacuum stress in the glass bulb and the flatness of the sealing surface between the panel and the funnel is low. In this case, the allowable stress value in the sealed portion is lower.

[0009]

A television using a cathode ray tube is disadvantageous in that it is heavier than a plasma display or a liquid crystal display, and therefore, there is a demand for a lighter glass bulb. Further, in recent years, a cathode ray tube having a face portion with higher flatness is desired in order to reduce distortion of an image as much as possible and improve visibility. But,
Such flattening of the face portion increases the asymmetry of the glass bulb shape and causes an unstable deformed state, so that the tensile vacuum stress generated in each portion increases. In addition, since the amount of glass used for reducing the weight is smaller than in the conventional case, higher deformation energy is accumulated in the glass bulb, and the possibility of breakage is increased.

Therefore, if the panel is thinned and the face portion is made flat to reduce the weight, the tensile vacuum stress generated in the face portion is significantly increased as described above. In order to solve the above problems, a strengthening method for applying a compressive stress to the panel surface has been developed so far.

Conventionally, as a means for reducing the weight of a glass bulb for a cathode ray tube, as shown in Japanese Patent No. 2904067, a physical strengthening method or the like is used to form the glass bulb on the surface of the panel by about 1/6 of that of glass. It has been put to practical use to form a compressive stress layer having a thickness. However, it is impossible to uniformly quench a panel or funnel having a three-dimensional structure and an uneven thickness distribution. As a result, a large tensile residual stress is generated together with the compressive stress due to the non-uniform temperature distribution. Therefore, the magnitude of the compressive stress is limited to about 30 MPa at most, and the large compressive stress cannot be applied. It was That is, when the physical strengthening method is used, the degree of weight reduction of the glass bulb is limited because the applied compressive stress is relatively small.

On the other hand, it is known that the surface of a glass bulb is strengthened by a chemical strengthening method to reduce the weight. This method is a method in which specific alkali ions in the glass are replaced with larger ions at a temperature below the strain point, and a compressive stress layer is formed on the surface by increasing the volume. For example, Na ₂
It is obtained by immersing a strontium-barium-alkali-alumina-silicate glass containing 5 to 8% of O and 5 to 9% of K ₂ O in a melt of KNO ₃ at about 450 ° C. In case of chemical strengthening method, 50MPa to 3
This is advantageous over weight reduction over physical strengthening in that a large compressive stress of about 00 MPa can be obtained and it is difficult to form unnecessary tensile stress.

Since the above-mentioned chemical strengthening method is usually carried out during the panel manufacturing process, that is, after being subjected to press molding and polishing, a high compressive stress can be applied to the face portion and the skirt portion. However, the sealing part is provided by attaching the shadow mask or the like to the inside of the panel and then welding the sealing edge part of the panel and the sealing edge part of the funnel with a sealing material such as solder glass. The compressive stress cannot be applied by the chemical strengthening method, and the difference in strength between the face portion and the sealing portion becomes wider.

On the other hand, by applying a high compressive stress to the face portion by the chemical strengthening method, it becomes possible to tolerate a higher tensile vacuum stress than before, and as a result, the face portion is made significantly thinner and lighter in weight. be able to. However, if the face portion is made as thin as possible on the basis of the compressive stress value given by the chemical strengthening method, the amount of deformation of the face portion is increased, so that the tensile vacuum stress generated in the sealing portion is further increased.

The sealing portion is formed by sealingly joining the panel and the funnel with the sealing material as described above.
The fired body of the sealing material such as solder glass has a strength of 60 to 70% as compared with the panel, and the strength of the sealing portion is considered to be the weakest in the glass bulb due to the strength of the sealing material. Become. Further, no compressive stress is applied to the sealed portion by the chemical strengthening method.

As a result, when a tensile vacuum stress is generated in a glass bulb using a thin panel in which a compressive stress layer is formed by the chemical strengthening method, the tensile vacuum stress within the allowable range is applied to the face portion of the panel. However, since there is a problem that the sealing portion reaches the upper limit of the allowable range, the face portion cannot be thinned as much as possible, which is a cause of hindering weight reduction.

The present invention has been made in view of the above problems, and it is possible to reduce the weight and / or the face portion by applying a high compressive stress by the chemical strengthening method without lowering the strength of the sealing portion. An object of the present invention is to provide a glass bulb for a cathode ray tube capable of achieving flatness and a highly safe cathode ray tube using the glass bulb for a cathode ray tube.

[0018]

In order to achieve the above object, the present invention is a glass bulb for a color cathode ray tube comprising a panel, a funnel connected to the panel, and a neck, wherein the panel has a rectangular shape. Of the face portion and a skirt portion that forms a side wall of the face portion and has a seal edge portion at the end portion, and 50 MPa is applied to at least one of the short axis end portion and the long axis end portion of the outer surface of the face portion.
A compressive stress σ _{c of} ≦ | σ _c | ≦ 250 MPa is applied by the chemical strengthening method, and the average thickness t of the face portion represented by the central thickness t _c of the face portion and the maximum thickness t _max of the face portion. = (T _c + t _max ) / 2 and the wall thickness t _se of the seal edge portion have a relationship of t / t _se ≦ 1.4, and are generated in the face portion by applying an internal vacuum. maximum value σ _{VTma x} of tensile stress, 20MPa ≦ σ _VTmax
Provided is a glass bulb for a color cathode ray tube, which is <200 MPa. Further, the present invention provides a color cathode ray tube characterized by using the glass bulb.

In the glass bulb for color cathode ray tube, the compressive stress σ _c is 50 MPa ≦ | σ _c | ≦ 200 MPa
It is more preferable if Furthermore, 80 MPa ≦ | σ _c
| ≦ 150 MPa, maximum value of tensile stress σ _VTmax
Is more preferably 20 MPa ≦ σ _Vtmax ≦ 100 MPa, since high industrial productivity can be obtained. Also,
In the glass bulb for color cathode ray tube of the present invention, the average thickness t of the face portion and the thickness t _{se of the} seal edge portion are
It is preferable that the ratio of t / t _se to be 0.5 ≦ t / t _se ≦ 1.0, because further weight reduction can be achieved without generating high tensile vacuum stress in the sealed portion.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
A glass bulb for a color cathode ray tube is referred to as a bulb and a glass panel is referred to as a panel.

In the present invention, the outer surface of the panel is a surface of the surface of the panel which is the outer side when the bulb is formed, and the inner surface is the back surface of the outer surface, and the phosphor is The surface to be applied, which is the inner surface when the valve is formed.

As shown in the plan view of the face portion of FIG. 3, among the axes passing through the center 21 of the face portion 7, the axis parallel to the short side 22 of the face portion is the short axis 23 of the face portion and the face portion. The axis parallel to the long side 24 is the long axis 25 of the face portion. In the panel of the present invention, 50 MPa is applied to at least the end 27 of the short shaft 23 (hereinafter referred to as the short shaft end) or the end 28 of the long shaft 25 (hereinafter referred to as the long shaft end) on the outer surface of the face portion. It is characterized in that a layer having a compressive stress σ _c of ≦ | σ _c | ≦ 250 MPa is formed by a chemical strengthening method. The short axis end portion 27 refers to a position where the short axis 23 intersects with the effective screen edge (viewing area edge) 26 and its vicinity, and the long axis end portion 28 refers to the long axis 25 when the effective screen edge. 26 and the vicinity thereof. In the present invention, the “rectangular face portion” includes one having a radius (curvature radius) at a corner as shown in the plan view of the face portion in FIG. It also includes a shape in which the short side 22 and / or the long side 24 is non-linear. That is, it means a substantially rectangular shape.

As a method for strengthening glass, a physical strengthening method is widely used. As described above, a compressive stress that can be applied by a physical strengthening method to a panel or funnel having a three-dimensional structure and an uneven thickness distribution. │σ _c │ is up to 30M
It was about Pa, and high compressive stress could not be applied. That is, when the physical strengthening method is used, since the compressive stress applied is relatively small, the degree of weight reduction of the glass bulb has been limited. However, in the case of the chemical strengthening method, a compressive stress | σ _c | of 300 MPa at maximum can be applied, which is suitable for weight reduction of the valve.

Here, in order to make the panel highly safe,
The compressive stress | σ _c | at the position of at least one of the short axis end and the long axis end of the outer surface of the face part is 50
It is necessary to set it to MPa or more, but the compressive stress | σ _c |
When it exceeds 50 MPa, when the panel is broken, the compression stress layer peels off and becomes finer, causing various problems in safety and production. Therefore, the value of the compressive stress is 50
MPa ≦ | σ _c | ≦ 250 MPa.

The above-mentioned chemical strengthening method is the following method. Generally, in silicate glass, elements of alkali and alkaline earth are irregularly introduced as network modifying ions in the network skeleton composed of Si-O bonds. Then, among the network-modifying ions, by utilizing the characteristic that monovalent cations can move inside the glass relatively freely, the alkali ions in the glass surface layer are exchanged with monovalent cations having a larger ionic radius in the external medium. can do. As a result, a larger ion enters into the escaped position of the alkali ion while compressing the surrounding mesh structure to generate a compressive stress. For example, N
A method of immersing strontium-barium-alkali-alumina-silicate glass containing 5 to 8% of a ₂ O and 5 to 9% of K ₂ O in a melt of KNO ₃ at about 450 ° C. (in the present invention, "Dip type ion exchange method") and the like are known. The chemical strengthening method of the present invention is not limited to the dip type ion exchange method.

In the present invention, the difference in rigidity between the face portion and the skirt portion (however, the rigidity of the face portion <
It has been found that transmission of deformation from the face portion to the sealing portion can be suppressed by further increasing the rigidity of the skirt portion) compared to the conventional one. When the difference in rigidity between the face portion and the skirt portion becomes large, the stress generated in the face portion increases, but the face portion cannot be destroyed because a high compressive stress can be applied by the above-mentioned chemical strengthening method. On the other hand, since the skirt portion has a relatively higher rigidity than the face portion, it is possible to suppress the generation of stress in the sealing portion.

Specifically, with respect to the thickness of the seal edge portion
By reducing the face wall thickness ratio,
The difference in rigidity between the skirt and the skirt can be increased.
It In addition, between the center part of the face part and the part other than the center part
Considering the difference in wall thickness, the central wall thickness t of the face part_c, Fe
Maximum wall thickness t_maxAverage of face part when
The wall thickness is t = (t_c+ T_max) / 2 and seal edge
Thickness of the part is t_seThen, the above “seal edge thickness”
The ratio of the average thickness of the face portion to _seTable
To be done.

In the present invention, t / t_seThe value of is smaller than before
That the above value is 1.4 or less
It is a feature. t / t_seValue of exceeds 1.4
And the face part is thick and the panel is heavy
Not allowing tensile vacuum stress generated in the face part
Even if there is still room for the upper limit of the range
The tensile vacuum stress generated at the welded part is at the upper limit of the allowable range.
Reach On the other hand, t / t_seIs less than 1.4
And because the above problems can be solved,
The part can be made as thin as possible to reduce the weight of the panel.
It Said t / t _seValue of 0.5 ≤ t / t_se≤1.0
If there is, it is caused by the deformation of the face part
Force is not transmitted to the skirt, so high tension is applied to the sealing part.
Thins the face without generating elastic vacuum stress
Because it is possible to reduce the weight further.
preferable.

Further, in the valve of the present invention, the inside is evacuated.
Tensile stress generated in the face part of the panel,
That is, the maximum tensile vacuum stress generated in the face
Value σ _VTmaxIs 20 MPa ≦ σ_VTmax<200 MPa
It is characterized by In the present invention, the vacuum is
A state of high vacuum.

In the above valve, σ _VTmax is 200M
If it is Pa or more, the valve may cause delayed fracture, so it is preferably less than 200 MPa, and if it is less than 20 MPa in view of safety, it is not possible to achieve thinness and weight reduction, so Σ
_VTmax is 20 MPa or more and less than 200 MPa. Further, the σ _VTmax is 20 MPa ≦ σ _Vtmax ≦ 100 MP
It is more preferable that it is a in terms of industrial productivity.

By using the valve having the above-mentioned structure, it is possible to manufacture a lightweight cathode ray tube having high safety such as strength and reliability.

[0032]

Example: Aspect ratio 16: 9, face effective screen diagonal diameter 860.0 mm, face maximum diagonal diameter 912.
0 mm, outer radius of curvature of face 17000.0 m
m, the inner radius of curvature of the face portion is 9400.0 mm, the height of the skirt portion is 120.0 mm, and seven types of panels having different face wall thicknesses and seal edge wall thicknesses are manufactured. It was set to 1-3.
At this time, as the glass material, those manufactured by Asahi Glass Co., Ltd. shown in Table 1 were used. The face wall thickness and the seal edge wall thickness of the examples and comparative examples are all designed so that the allowable stress value at the sealing portion is 8.5 MPa.

[0033]

[Table 1]

Next, the panels of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 were immersed in a KNO ₃ melt for 4 hours.
It was heated at 50 ° C. for 6 hours, and subjected to the chemical strengthening treatment by the above-mentioned dip type ion exchange method to form a compressive stress layer on the surface. Further, the panel of Example 3 was immersed in a KNO ₃ melt and heated at 440 ° C. for 12 hours, and the panel of Example 4 was immersed in a KNO ₃ melt and 440 ° C. ×.
After heating for 24 hours, chemical strengthening treatment was performed by a dip type ion exchange method to provide a compressive stress layer on the surface. Comparative Example 3
For the panel (1), cooling air was blown after the molding to generate strain, and then the temperature was adjusted in a slow cooling furnace so that the strain was not completely removed, and slow cooling was performed to provide a compressive stress layer. Table 2 below shows the values of the compressive stress value | σ _c | given to the short axis end of each example.

Subsequently, after measuring the mass of each panel, the funnel and each of the above panels were further sealed by using a sealing material (trade name: ASF-1307R) manufactured by Asahi Glass Co.
The bulb was formed by firing at 0 ° C. for 35 minutes for hermetically sealing and connecting the funnel and neck together. Then, when the inside of the valve is in a vacuum state and the tensile vacuum stress generated in the sealed portion is the allowable stress value of the sealed portion (8.5 MPa), the tensile force generated in the minor axis end portion of the face portion. The maximum value σ _VTmax of the _elastic vacuum stress was measured.

In the following Table 2, the thickness of the face center: t _c (mm), the maximum thickness of the face: t _max (mm), the average thickness of the face: t (mm) = (t _c + t _max ) /
2. Seal edge thickness: t _se (mm), t / t _se , compressive stress value applied to the minor axis end of the panel outer surface: σ
_c | (MPa), allowed the face portion stress value: σ _Af (MPa), the allowable stress values at the sealing portion: σ _As (MPa), the panel Mass: m _p (kg), tensile properties generated in the sealing portion Vacuum stress: σ _VTs (Mpa)
And maximum tensile vacuum stress generated in the face: σ
_VTmax (MPa) is shown.

In this example, the compressive stress value σ _c
Was measured as follows. As one of the stress measurement methods for glass, there is a method for measuring by utilizing the property that the difference in refractive index in the principal stress direction generated when glass receives a force is proportional to the stress difference. When linearly polarized light is passed through stressed glass, the transmitted light is decomposed into component waves having polarization planes orthogonal to each other in the directions of the principal stresses and having different velocities. After passing through the glass, the respective component waves lag one behind the other, and the refractive index of the glass also differs in each principal stress direction depending on the velocity of the component waves. Since the stress difference of glass is proportional to the difference in refractive index, so-called birefringence, the stress can be measured if the phase difference of the component waves is known.

The stress is measured by transmitting light to the glass cross section having residual stress by a polarization microscope using this principle and measuring the phase difference of the component vibrating in the main stress direction after the transmission. At this time, a polarizer is arranged before passing through the glass, and a plate having a phase difference after passing through the glass and an analyzer for detecting polarized light are arranged. Examples of plates having a phase difference include Berek compensator, Babinet compensator, and quarter-wave plate. By using these, a dark line can be created so that the phase difference in the region to be measured becomes zero, so that the stress value can be known from the adjustment amount of the compensator.

Further, instead of the various compensators described above, a sensitive color plate having an optical path difference of about 565 nm and changing the interference color by a slight change in the optical path difference is used, whereby a small amount of light is transmitted after passing through the glass. The interference color depending on the phase difference due to refraction can be represented, and the color can make the level of stress distinguishable. Utilizing this property,
The glass cross section is observed and the thickness of the stress layer is measured. In addition,
In this example, a Berek compensator was used as the plate having a phase difference.

Further, σ _VTs and σ _VTmax are strain gauges KFG-5-120-D1 manufactured by Kyowa Denki Co., Ltd. at desired positions.
6-11 was attached and measured.

[0041]

[Table 2]

Compared to the product of Comparative Example 3 provided with a compressive stress layer by the physical strengthening method, the products of Examples 1 to 4, Comparative Example 1 and Comparative Example 2 provided with a compressive stress layer by the chemical strengthening method have an outer surface. It was possible to apply a high compressive stress and to reduce the mass by 20% or more. In particular, regarding the products of Examples 1 and 2 in which the value of t / t _se was 1.4 or less, the face portion was compared with Comparative Examples 1 and 2 in which t / t _se > 1.4. Since the wall thickness can be reduced, it is possible to reduce the weight by about 30% as compared with Comparative Example 3. Also, t
The product of Example 3 in which / t _se is 0.9 and the compressive stress value | σ _c | is 160 MPa can achieve a weight reduction of about 33%.
The product of Example 4 in which / t _se was 0.8 and the compressive stress value | σ _c | was 240 MPa could achieve a weight reduction of about 39%.

[0043]

EFFECT OF THE INVENTION The valve of the present invention ensures that the strength of the sealing portion is ensured by setting the ratio of the wall thickness of the face portion of the panel to the seal edge portion within a suitable range, while the tension generated in the face portion is maintained. Since the compressive stress that cancels the maximum value of the elastic vacuum stress is given to at least the short axis end or the long axis end of the outer surface of the face part of the panel by the chemical strengthening method, the face part can be thinned to the maximum extent, As a result, a lightweight valve can be provided. Further, by using the bulb, it is possible to provide a lightweight and safe cathode ray tube.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the configuration of a cathode ray tube.

FIG. 2 is an enlarged explanatory view showing the vicinity of the sealing portion.

FIG. 3 is a plan view showing a face portion.

[Explanation of symbols]

1: Cathode ray tube 2: Glass bulb 3: Panel 4: Funnel 5: neck 6: Skirt part 7: Face part 10: Sealing part 21: Center of face 23: Face part short axis 25: Face long axis 27: Face part short axis end part 28: Face long axis end

Claims (5)

[Claims] 1. A glass bulb for a color cathode ray tube comprising a panel, a funnel connected to the panel, and a neck, wherein the panel comprises a rectangular face portion and a side wall of the face portion at an end thereof. A skirt having a seal edge, and 50 MPa ≦ | σ _c | ≦ 25 on at least one of the short axis end and the long axis end of the outer surface of the face section.
A compressive stress σ _{c of} 0 MPa is applied by the chemical strengthening method, and the average thickness t of the face portion represented by the central thickness t _c of the face portion and the maximum thickness t _max of the face portion t =
_{(T c + t ma x)} / 2 and the seal edge portion of the wall thickness t _se
And t have a relationship of t / t _se ≦ 1.4, and the maximum value σ _{VT max of} tensile stress generated in the face portion when the inside is evacuated is 20 MPa ≦ σ _VTmax <2
A glass bulb for a color cathode ray tube, which has a pressure of 00 MPa. 2. The compressive stress σ _c is 50 MPa ≦ | σ _c | ≦
It is 200 MPa, The glass bulb for color cathode ray tubes of Claim 1 characterized by the above-mentioned. 3. The compressive stress σc is 80 MPa ≦ | σ _c | ≦
150 MPa, the maximum value of the tensile stress σ _VTmax
Is 20 MPa ≤ σ _Vtmax ≤ 100 MPa, the glass bulb for a color cathode ray tube according to claim 2. 4. The ratio t / t _se between the average thickness t of the face portion and the thickness t _se of the seal edge portion is 0.5 ≦ t / t.
_{se 1} ≤ 2, wherein _se ≤ 1.0
Alternatively, the glass bulb for a color cathode ray tube according to claim 3. 5. A color cathode ray tube comprising the glass bulb for a color cathode ray tube according to any one of claims 1 to 4.