JP2002100309A - Cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube wherein differences between the central and peripheral transmissivities are small, a contrast is high, dispersions of surface reflected chromaticity is suppressed, and generation of reflected color unevenness can be prevented even if glass wall thickness differences of central and peripheral face parts of a glass panel are large. SOLUTION: A colored film is formed so that the overall transmissivity combined with the glass panel and the colored film becomes higher at a corner part than at the central part of the face part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube used for a television receiver or a display for a personal computer.

[0002]

2. Description of the Related Art FIG. 4A is a partially cutaway explanatory view showing the structure of a general cathode ray tube, and FIG. 4B is a plan view thereof. This cathode ray tube has a glass panel 11 having a fluorescent film 10 on its inner surface, a funnel-shaped funnel 12 behind the glass panel 11, and a neck 1 for accommodating an electron gun.
3 is provided as an envelope. A shadow mask 14 is provided on the inner surface of the glass bulb so as to face the fluorescent film 10, and an electron beam emitted from an electron gun passes through the shadow mask 14 to form the fluorescent film 1.
By irradiating 0, an image is projected on the effective surface 11a of the front portion (hereinafter, referred to as a face portion) of the glass panel 11.

The inside of such a cathode ray tube is in a high vacuum state, and a compressive stress and a tensile stress are generated in the glass bulb. Therefore, when a mechanical shock is applied to the glass bulb, there is a danger of implosion. There is. For this reason, the thickness of the face portion of the glass panel 11 is generally thicker at its peripheral portion 11b than at the central portion 11c in order to maintain sufficient strength as a cathode ray tube, and particularly at the diagonal end portion of the effective surface 11a. The area near 11d (hereinafter referred to as a corner) is the thickest.

[0004] Therefore, the ordinary glass panel tends to have a difference in light transmittance between the central portion and the peripheral portion of the face portion. As a result, the brightness at the peripheral portion, particularly at the corner portion, becomes lower than that at the central portion of the face portion, and the brightness of the image becomes uneven, making it difficult to see.

[0005] The transmittance of the glass constituting the glass panel varies depending on the application. The higher the transmittance of the glass itself constituting the glass panel, the smaller the difference in transmittance due to the difference in thickness between the central portion and the peripheral portion of the face portion, but the contrast decreases.

[0006] From such a background, by using a glass panel made of glass having high transmittance,
Attempts have been made to reduce the transmittance difference between the central region and the peripheral region, and to improve the contrast by attaching a colored glass plate to the face portion with an adhesive.

In recent years, flattening of glass panels has been demanded, and attempts have been made to increase the radius of curvature of the outer surface of the face portion in the diagonal axis direction to 10,000 mm or more. However, since the risk of implosion increases as the radius of curvature of the face portion of the glass panel increases, the radius of curvature in the diagonal axis direction of the outer surface of the face portion of the glass panel is set to 10,000 mm or more as described above. Are designed such that the thickness (te) of the corner portion of the face portion and the thickness (t ₀ ) of the central portion satisfy the expression of 1.2 ≦ te / t ₀ ≦ 4.0. .

However, if the thickness difference between the central portion and the corner portion of the face portion of the glass panel becomes too large, even if the glass panel is made of glass having high transmittance, the transmission of the central portion and the corner portion will not occur. It becomes difficult to sufficiently reduce the rate difference.

Further, the cathode ray tube becomes heavier as the thickness of the face portion of the glass panel becomes larger. However, if a colored glass plate is pasted on the front surface of the cathode ray tube, the weight of the cathode ray tube is further increased, making transport difficult. There is also.

Further, when a colored glass plate is attached to the face portion, bubbles may be mixed into the adhesive at the time of attachment,
Striae may occur, making the image difficult to see. In addition, there is a possibility that the adhesive will deteriorate during use for a long period of time and the colored glass plate will peel off.

Under such circumstances, the applicant of the present invention has disclosed in Japanese Patent Application Laid-Open No. 11-283529 that the thickness of the portion corresponding to the thick portion of the face portion is small and the thickness of the portion corresponding to the thin portion of the face portion is small. A thick colored film is formed on the outer surface of the glass panel where the thickness of the part to be formed is small. This makes it possible to reduce the difference in transmittance due to the difference in thickness between the center and peripheral parts of the face, and propose a cathode ray tube with high contrast. are doing.

[0012]

The emission luminance of the cathode ray tube is also affected by the stripe width of the fluorescent film on the inner surface of the glass panel. In the fluorescent film, the carbon stripe width at the peripheral portion of the fluorescent film is wider than the central portion, that is, the phosphor stripe width at the peripheral portion is narrower than that at the central portion, in order to suppress occurrence of mislanding due to terrestrial magnetism. For,
Light emission luminance is lower at the peripheral portion of the face portion, particularly at the corner portion, than at the central portion, and the periphery of the image looks slightly darker.

Japanese Patent Application Laid-Open No. H11-283529 discloses that the difference in transmittance due to the difference in thickness between the central portion and the peripheral portion of the face portion is reduced by a colored film. Only a cathode ray tube in which the transmittances of the part and the peripheral part are matched is illustrated, and there is no suggestion at all for correcting a decrease in light emission luminance at a corner part of the face part due to a difference in phosphor stripe width.

An object of the present invention is to provide a cathode ray tube in which a colored film is formed on the outer surface of a glass panel to reduce a difference in light emission luminance between a corner portion and a center portion of a face portion.

[0015]

A cathode ray tube according to the present invention is a cathode ray tube in which a colored film is formed on an outer surface of a face portion of a glass panel, and has a total transmittance of a combination of the glass panel and the colored film. The color film is formed so as to be higher at the corners than at the center of the face.

Further, in the cathode ray tube of the present invention, the colored film has a small thickness at a portion corresponding to a thick portion of the face portion of the glass panel, and has a thin film corresponding to a thin portion of the face portion of the glass panel. It is characterized in that the thickness of the portion to be formed is large.

Further, the cathode ray tube according to the present invention is characterized in that the outer surface of the face portion of the glass panel has a radius of curvature in the diagonal axis direction of 10,000 mm or more, and the thickness of the corner portion of the face portion of the glass panel is reduced. te, where t ₀ is the thickness of the central portion, the expression 1.2 ≦ te / t ₀ ≦ 4.0 is satisfied, and the face portion of the glass panel having a colored film formed on the outer surface thereof Transmittance at the corners of the glass (transmittance when the glass panel and the colored film are combined)
Is Te, and the total transmittance of the central portion (central portion) is T ₀ , wherein the formula 1.05 ≦ Te / T ₀ ≦ 1.75 is satisfied, and 1% ≦ Te−T ₀ ≦ It is characterized by satisfying the equation of 10%.

In the glass panel of the present invention, only the glass panel having a two-dimensional distribution of glass thickness, and the entire thickness of the periphery of the face portion gradually becoming thicker than the thickness of the center portion. In addition, the so-called cylindrical type glass panel, in which the glass thickness has a one-dimensional distribution, and the thickness of both ends on the long axis side of the face portion gradually becomes larger than the thickness of the central portion, is included. It is.

[0019]

In the cathode ray tube of the present invention, since the colored film is formed on the outer surface of the glass panel so that the total transmittance at the corners of the face is higher than the total transmittance at the center, the cathode ray tube has The difference in transmittance and the difference in luminance between the corner and the center are reduced, and the brightness of the entire image becomes uniform.

In the colored film used in the present invention, the thickness of the portion corresponding to the thick portion of the face portion of the glass panel (the portion having a narrow phosphor stripe width) is small, and the thickness of the face portion of the glass panel is small. By reducing the thickness of the portion corresponding to the thin portion (the portion where the phosphor stripe width is wide), the total transmittance at the corners of the face portion can be made higher than the total transmittance at the center portion. It becomes possible.
The contrast is also improved by the colored film.

In the present invention, the radius of curvature of the outer surface of the face portion of the glass panel in the diagonal axis direction is 10,000 mm.
In the above case, when the thickness of the corner portion of the face portion of the glass panel is te and the thickness of the central portion is t ₀ in consideration of explosion protection, te / t ₀ is 1.2 or more. In any case, the expression 1.05 ≦ Te / T ₀ ≦ 1.75 is satisfied, the expression 1% ≦ Te−T ₀ ≦ 10% is satisfied, and the brightness of the entire image is substantially equalized. It becomes possible. However, it is not preferable that te / t ₀ is larger than 4.0 because the weight of the cathode ray tube becomes too large.

In the present invention, if the glass panel is made of glass having a low light transmittance, the brightness of the entire display image is reduced. Therefore, the glass is converted to a glass having a high light transmittance, specifically, a thickness of 10.16 mm. In this case, the light transmittance at a wavelength of 550 nm is preferably made of glass having a transmittance of 70% to 91%. On the other hand, if the value of Te / T ₀ is larger than 1.75, the brightness at the corners of the face becomes too large, which is not preferable.

The colored film of the present invention can be formed by a sputtering method, a spin coating method, or a spray coating method.
For example, when a film is formed by a sputtering method, a shielding plate for adjusting the amount of the sputtered material attached between the glass panel and the target is provided, or sputtering is performed while adjusting the moving speed of the glass panel. When the colored film is formed on the outer surface of the face part by the method, the film thickness of the part corresponding to the thick part of the face part is thin, and the film thickness of the part corresponding to the thin part of the face part of the glass panel It is possible to obtain a thick colored film.

The sputtering method will be described in more detail. For example, as shown in FIG.
16a corresponding to the vicinity of the center of the face 11a
A method in which a mesh-shaped metal shielding plate 16 having a large opening and a small opening in a portion 16b corresponding to the vicinity of the corner of the face portion 11a is sputtered while moving in front of the target 15 together with the glass panel 11 is applied. it can.

As another method, as shown in FIG. 2, the interval between the glass panel 11 and the target 15 near the center of the face 11a of the glass panel 11 is wide, and the face A pair of metal shielding plates 17, 17 having a shape such that the interval between portions corresponding to both ends in the short axis direction of the short side of 11 a is reduced, and both ends of the face portion 11 a of the glass panel 11 in the long axis direction The moving speed when passing near the target 15 in front of the target portion is high, and conversely, the target 1 is located near the center portion of the face portion 11a.
A method in which sputtering is performed while moving the glass panel 11 so that the moving speed when passing in front of 5 is reduced can be applied.

When a colored film is formed by the spin coating method, the temperature of the thin portion of the face portion of the glass panel is rotated while the temperature of the thin portion is higher than the temperature of the thick portion. What is necessary is just to apply a colored coating solution dropwise to the center of the outer surface, and to dry it. Since the applied amount of the colored coating liquid increases as the temperature of the glass panel increases, the thickness of the formed colored film increases from the thicker portion to the thinner portion of the face portion of the glass panel.

Further, when a colored film is formed by the spray coating method, a colored coating solution is spray-coated on the face of the glass panel using a spray coating device. At this time, the spray coating device is moved in the long axis direction of the glass panel (and also in the short axis direction as necessary), and the moving speed is
If the speed is slower in the thinner part of the face part and faster in the thicker part of the face part, the thickness of the coloring film formed from the thicker part to the thinner part of the face part of the glass panel becomes larger. It gets thicker.

Such a colored film forming operation can be performed on the face portion of the panel after the glass panel is sealed in a funnel and the cathode ray tube is assembled, and as shown in FIGS. As described above, it can be performed on the glass panel before sealing with the funnel.However, the latter forms the film on the glass panel alone, so the film forming equipment does not become excessive and the workability is improved. Good and preferred.

As the material of the colored film in the present invention, any material can be used as long as it has a function of lowering the transmittance of the glass panel and can obtain a desired film thickness. For example, when the sputtering method is adopted, Ti
N, TiO ₂ , Nd ₂ O ₃ , NiO, NbN and the like are suitable. In particular, a colored film made of TiN is preferable because it has excellent heat resistance, low specific resistance, and can be formed relatively easily. When spin coating or spray coating is employed, Au, Ag, Pt, Pd, Rh, Cu, F
e, Ni, Co, Sn, In, Ru, Ti, Al, Ta
Metal fine particles such as these, compounds containing these metals, or various organic pigments can be used.

The thickness of the colored film varies depending on the film material used, the form of the panel glass, and the like. The thickness at the center of the face portion is 50 to 10,000 ° and the thickness at the corner portion is 1 to 5000 °. It is appropriate to do.

Further, in the present invention, in addition to the above-mentioned colored film, a dielectric film having a different refractive index (for example, SiO ₂ , Si ₃
N ₄ , Nb ₂ O ₅ , SnO ₂ , Al ₂ O ₃ , AlN, AlO
N, SiON) may be laminated to form a multilayer film of two or more layers, so that antireflection performance and the like can be imparted. For example, a colored film made of TiN (for example,
The center film thickness is 1200 膜厚 and the peripheral film thickness is 900Å).
When an iO ₂ film (e.g., a film thickness of 900 °) is laminated, a multilayer film having excellent conductivity and antireflection properties can be obtained, and a Si ₃ N ₄ film (e.g., a film thickness of 500 °) is provided between the TiN film and the SiO ₂ film.
By interposing Å), a multilayer film having excellent heat resistance can be obtained, whereby the change in reflectance after heat treatment of the multilayer film is reduced.

When a multilayer film of five or more layers is formed by laminating the above-mentioned colored film and dielectric film, even if a glass panel is made of glass having a high light transmittance, the surface reflectance is remarkably reduced. This suppresses the rise in reflectance and prevents the image from appearing double.

Further, in the case of a conductive anti-reflection film including two or more colored films, variation in the surface reflection chromaticity can be obtained by changing the thickness of the at least two colored films at the center and the corner of the face. There is an advantage that it can be suppressed. In other words, if there is only one colored film whose thickness has been changed,
The difference in film thickness between the center part and the corner part of the face part becomes very large, and the surface reflection characteristics change between the center part and the corner part due to the interference effect between the coloring film and the antireflection film, and the difference in the surface reflection chromaticity Reflection color unevenness is likely to occur, but if two or more colored films are used, the difference in film thickness between the central part and the corner part of each colored film can be reduced, and the surface reflection chromaticity at the central part and the corner part can be reduced. Differences can be suppressed. By the way, in order to correct the difference in the chromaticity of the surface reflection, the thickness of the center portion and the corner portion of the face portion of the dielectric film may be changed, but the manufacturing conditions become complicated and the surface reflection is completely completed. It is difficult to suppress chromaticity variations.

[0034]

The present invention will be described below in detail based on examples and comparative examples.

(Example 1) FIG. 3 is a partially cutaway schematic explanatory view showing a cathode ray tube (21 inches) of the present invention, in which a glass panel 11, a funnel 12, and a neck 13 are sealed in a glass bulb. , Fluorescent film 10, shadow mask 1
4 and an electron gun.

The face of the glass panel 11 of this cathode ray tube
Thickness (t) at the center (center) of the ₀) Is 10mm,
The wall thickness (te) of the corner part is 15mm, and the outer surface of the face part
The radius of curvature in the diagonal axis direction of the surface is 100000 mm
Yes, the glass transmittance at the center of the face is 80%,
The glass transmittance of the toner part is 70%.

On the outer surface of the face of the glass panel 11, a colored film 18 made of conductive silver / palladium is formed.
0 °, and the film thickness at the corner is 270 °.

This cathode ray tube was manufactured by the following method.

First, the glass panel 11 was set on a spin coater so that the outer surface faced upward. Thereafter, the temperature of the corner portion of the face portion of the glass panel 11 is about 37 ° C. and the temperature of the central portion thereof is about 50 ° C. using a heater.
With the glass panel 11 heated to about 1
While rotating at a speed of 00 rpm, a silver / palladium colored coating solution (solid content 0.2
5%), a glass panel 1
A colored film 15 was applied and formed on the entire outer surface of the face portion of No. 1.

When the transmittance of the glass panel 11 with the colored film thus obtained was measured, the total transmittance (T ₀ ) at the center of the face portion was 40%, and the total transmittance (Te) at the corner portion was 46%. A cathode ray tube was manufactured using this glass panel 11, and the luminance ratio between the center of the image and the corner was measured. As a result, corner / center = 0.99.

Example 2 Using the same glass panel as in Example 1, a cathode ray tube having a three-layer film formed on its outer surface was manufactured. The three-layer film is composed of a Si ₃ N ₄ film, a Ti film from the glass side.
An N film and a SiO ₂ film are stacked in this order. The thickness of the central portion of the TiN film is 1200 °, and the thickness of the corner portion is
900Å. Further, the Si ₃ N ₄ film and the SiO ₂ film provide antireflection performance and heat resistance performance, and these films have a uniform film thickness throughout, and
Å and 600Å.

The Si ₃ N ₄ film, TiN film and SiO ₂ film of this glass panel were produced by the following method.

Using a magnetron sputtering film forming apparatus, T
For the iN film, a metal mesh-shaped shielding plate as shown in FIG.
On the outer surface of the face portion of No. 1, a colored film having a different thickness at the central portion and the corner portion was formed. For the Si ₃ N ₄ film and the SiO ₂ film, a dielectric film having a uniform film thickness is formed by performing sputtering using the same magnetron sputtering film forming apparatus without using the above-described shielding plate. did.

When the transmittance of the glass panel with a film thus obtained was measured, the total transmittance (T ₀ ) at the center portion of the face portion was 50%, and the total transmittance (Te) at the corner portions was 50%.
Was 57%, and the luminance ratio between the center of the image and the corner of the cathode-ray tube using this glass panel was measured.

The glass panel 11 was placed in a box-type electric furnace, and was subjected to a heat treatment at 450 ° C. for 60 minutes.
Was measured, the surface reflectance was as low as 1.0%, indicating that it had excellent antireflection properties.

Comparative Example 1 A colored film was formed under the same conditions as in Example 1 except that a colored coating solution was dropped on the outer surface of the glass panel while the temperature of the corner of the face was heated to about 40 ° C. Was formed on the glass panel.

The colored film formed on the outer surface of the glass panel has a thickness of 550 ° at the center of the face portion and 300 ° at the corner portion, and the transmittance thereof is measured. Both the total transmittance (T ₀ ) at the center and the total transmittance (Te) at the corners were 40%. A cathode ray tube was manufactured using this, and the luminance ratio between the center of the image and the corner was measured. As a result, the ratio of corner / center = 0.88, and the luminance difference was larger than that in Example 1.

Comparative Example 2 A three-layer film was formed on the outer surface of the face of the same glass panel as in Example 1 by performing sputtering using a magnetron sputtering film forming apparatus. The three-layer film was formed by stacking a Si ₃ N ₄ film, a TiN film, and a SiO ₂ film in this order from the glass side. The thickness of the TiN film is 1200 ° at the center and 1000 ° at the corners, and the Si ₃ N ₄ film and the SiO ₂ film have a uniform thickness over the entire surface, each being 500 °. 600 °.

When the transmittance of the glass panel with the film was measured, the total transmittance (T ₀ ) at the center of the face portion was 50%, and the total transmittance (Te) at the corner portion was 49%. When the luminance ratio between the center and the corner of the image of the cathode ray tube using the panel was measured, the corner / center =
0.87, which is larger than that in Example 2.

The transmittance of the above-mentioned glass panel is determined by the luminous average transmittance of a wavelength of 380 to 780 mm measured by a spectrophotometer, and the surface reflectance is measured using an instantaneous multi-reflectometer. ° Specular reflection was measured, and the luminance ratio was measured using a luminance meter.

[0051]

As described above, the cathode ray tube of the present invention uses a glass panel having different thicknesses at the center part and the corner part of the face part, but also uses the colored film to form the center part and the corner part of the face part. Since the difference in transmittance due to the difference in transmittance and the difference in the width of the phosphor stripe between the center and the corner is corrected, the difference in brightness between the center and the corner of the image is reduced, and the brightness of the entire image becomes uniform.

Further, since the cathode ray tube of the present invention has a colored film formed on the outer surface of the glass panel, the weight increase is remarkably small as compared with the case where a colored glass plate is used, and the cathode ray tube is used for a long time. A good image surface can be maintained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a sputtering method suitable for producing a cathode ray tube of the present invention.

FIG. 2 is an explanatory view showing another example of the sputtering method suitable for producing the cathode ray tube of the present invention.

FIG. 3 is a schematic explanatory view, partially broken away, showing a structure of a cathode ray tube of the present invention.

FIG. 4 (a) is a partially cutaway schematic explanatory view showing the structure of a general cathode ray tube, and FIG. 4 (b) is a plan view thereof.

[Description of Signs] 11 Glass panel 11a Effective face of face portion 11c Center portion of face portion 11d Corner portion of face portion 12 Funnel 13 Neck 15 Target 16, 17 Shielding plate 18 Colored film

Continued on the front page F term (reference) 4G059 AA07 AB05 AB09 AB11 AC04 AC08 DA01 DA02 DA03 DA04 DA05 DA06 DA07 DA08 DA09 DB09 EA01 EA04 EA05 EA12 EB04 GA01 GA02 GA04 GA12 GA14 5C032 AA02 BB05 DD02 DE01 DF01 DF03 DF05 DF05

Claims (6)

[Claims] 1. A cathode ray tube in which a colored film is formed on an outer surface of a face portion of a glass panel, wherein a total transmittance of a combination of the glass panel and the colored film is higher at a corner portion than at a central portion of the face portion. A cathode ray tube comprising a colored film formed as described above. 2. The colored film has a small thickness at a portion corresponding to a thick portion of a face portion of a glass panel, and a colored film has a small thickness at a portion corresponding to a thin portion of a face portion of a glass panel. 2. The cathode ray tube according to claim 1, wherein the cathode ray tube is thick. 3. The cathode ray tube according to claim 1, wherein the outer surface of the face portion of the glass panel has a radius of curvature in a diagonal axis direction of 10,000 mm or more. 4. When the thickness of the corner portion of the face portion of the glass panel is te and the thickness of the central portion is t ₀ , 1.2.
Cathode ray tube according to claim 1, characterized by satisfying the ≦ te / t ₀ ≦ 4.0 equation. 5. The overall transmittance of the corner portion of the face portion of the glass panel colored film on the outer surface of which is formed Te, the total transmittance of the central portion when the _{T 0, 1.05 ≦ Te / T} 0
The formula satisfies the following expression: ≤1.75.
5. The cathode ray tube according to any one of 4. 6. The cathode ray tube according to claim 1, wherein the following expression is satisfied: 1% ≦ Te−T ₀ ≦ 10%.