JP2001155664A - Color cathode ray tube and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode ray tube(CRT) that may be produced at low cost without requiring the processes of increasing the thickness of the transparent conductive layer to reduce the sheet resistance, forming the terminal pad by ultrasonic soldering or conductive frit to ensure electrical connection between the transparent conductive layer and conductive tape, and increasing the number of conductive tapes attached to the periphery of the face panel with the sheet resistance. SOLUTION: A liquid composed of conductive particles and liquid glass is applied to the surface of the face panel 11, and then, a liquid composed of anti-reflection particles and liquid glass over it, which is burned together so as to simultaneously form the transparent conductive layer 15 and anti- reflection coating 16, that electrical conduction of the transparent conductive layer 15 is made through the anti-reflection coating 16.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly, to a color cathode ray tube having a face panel surface treated so as to satisfy an alternating electric field standard such as TCO, and a method of manufacturing the same.

[0002]

2. Description of the Related Art In recent years, it has been considered that electromagnetic waves have an adverse effect on the human body, and there is a concern that an alternating electric field generated mainly by a deflection yoke may adversely affect the human body for a color CRT display monitor. In light of these circumstances, the Swedish National Metrology and Testing Council and the Swedish Central Labor Council (TCO) have stipulated standards for allowable electromagnetic waves leaking from display monitors.

According to the standards of the Swedish Central Labor Council (TCO), among the electromagnetic waves emitted from a display monitor at a point 30 cm from a panel of a color cathode ray tube, an alternating electric field of 2 kHz to 400 kHz (VLF band) is 1 V / m or less. An alternating electric field of 5 Hz to 2 kHz (ELF band) is specified to be 10 V / m or less. Conventionally, in an alternating electric field shield type color cathode ray tube, particularly, 2 kHz to 400 kHz (VLF)
It has been found that it is very difficult to take measures to shield the alternating electric field in the band.

FIG. 5 is a front view and a side view of an example of a conventional color cathode ray tube 50 in which a shielding measure is taken. In the figure, 51 is a face panel, 52 is a protective tape, 53 is an explosion-proof band, 54 is a conductive tape, and 55 is a terminal pad. FIG. 6 is an enlarged sectional view of a portion A of the color CRT 50 of FIG. In the figure, 56 is a transparent conductive film, 57
Is an antireflection film.

[0005] As shown in FIGS. 5 and 6, a transparent conductive film 56 is provided on the surface of the face panel 51.
A terminal pad 55 is provided at one peripheral end, and the terminal pad 55
To earth. The resistance value of the transparent conductive film 56 is 5000 when the horizontal frequency is 30 kHz or more.
When the horizontal frequency is 45 kHz or more, the resistance is 3000 Ω / □ or less.

Next, a method of forming a laminated film on the surface of the face panel 51 of the conventional color cathode ray tube 50 shown in FIGS. 5 and 6 will be described. First, the transparent conductive film 5 is formed on the outer surface of the face panel 51.
As No. 6, a Nesa film mainly composed of tin oxide is formed by atmospheric pressure thermal CVD.
(About 480 ° C.). Since the Nesa film has a higher refractive index than that of the glass of the face panel 51, the surface reflection increases and the image becomes difficult to see. In order to suppress the surface reflection, a silica film having a lower refractive index is formed as an anti-reflection film 57 on the Nesa film. Then apply silica film for about 4
It is fixed by heat treatment at 50 ° C. Before the heat treatment of the silica film, a conductive frit is applied to the peripheral end of the panel 51 and baked simultaneously with the silica film to form the terminal pad 55.

The above-mentioned laminated films 56 and 57 and terminal pads 55
After a black matrix, a phosphor film, and a metal back film are formed on the inner surface of the face panel 51 on which is formed, a shadow mask, an inner shield, a getter, and the like are mounted to seal a funnel coated with graphite inside. Further, an electron gun is mounted on the neck to evacuate the inside. Further, a protective tape 52 and an explosion-proof band 53 for safety are wound around the outer periphery of the face panel 51. After the explosion-proof band 53 is wound, a conductive tape 54 is attached between the terminal pad 55 on the surface of the face panel 51 and the explosion-proof band 53 as shown in FIG. Finally, the deflection yoke is mounted, and final adjustment is performed to complete the conventional color cathode ray tube 50.

[0008]

As described above, in the conventional color cathode ray tube 50, the sheet resistance of the transparent conductive film 56 needs to be 3000Ω / □ to 5000Ω / □ or less. When the thickness of the transparent conductive film 56 is small, it is necessary to increase the conductivity of the film in order to reduce the sheet resistance, but this is technically difficult. Conversely, if the film thickness is increased, the sheet resistance can be reduced, but the cost of the transparent conductive film 56 increases. However, since there is no other method, the sheet resistance has conventionally been unavoidably increased by increasing the film thickness.

Further, in the conventional color cathode ray tube 50,
In order to secure conduction between the transparent conductive film 56 and the conductive tape 54, it is necessary to form the terminal pad 55 with ultrasonic solder or conductive frit. Further, as the sheet resistance of the transparent conductive film 56 is higher, it is necessary to apply more conductive tape 54 around the face panel 51. From the above, the conventional alternating electric field shield type color cathode-ray tube 50 has been expensive.

The present invention solves such a problem of the conventional color cathode ray tube by selecting the materials of the transparent conductive film and the antireflection film and simultaneously firing them as described below. A color cathode ray tube having an effect is realized at low cost.

[0011]

In order to achieve the above object, a color CRT according to the present invention comprises applying a solution containing conductive particles and water glass to the face panel surface, and further comprising antireflection particles and water glass thereon. The solution is applied, and the two are baked together to simultaneously form the transparent conductive film and the antireflection film, and to form a mixed state of the antireflection film and the transparent conductive film, thereby forming the surface of the antireflection film. In this case, electrical conduction with the transparent conductive film can be obtained.

According to a first aspect of the present invention, there is provided a color cathode ray tube having a laminated film in which at least a transparent conductive film and an antireflection film are laminated in this order on a face panel surface, and the color cathode ray tube is directly adhered to the surface of the antireflection film. The obtained conductive tape secures electrical conduction between the transparent conductive film and the explosion-proof band.

According to a second aspect of the present invention, the transparent conductive film is a film containing ruthenium oxide as conductive particles, a film containing silver as conductive particles, or
It is a film containing palladium as conductive particles or a film containing silver-palladium alloy as conductive particles.

According to a third aspect of the present invention, the antireflection film is a film containing silica as a low refractive index material.

According to a fourth aspect of the present invention, the conductive tape is an aluminum tape or a copper tape.

According to a fifth aspect of the present invention, the transparent conductive film has a sheet resistance of 15000 Ω / □ or less.

According to a sixth aspect of the present invention, the conductive tape is applied only near the center of the long side of the face panel.

According to a seventh aspect of the present invention, the conductive tape is attached only near the center of the short side of the face panel.

According to an eighth aspect of the present invention, a solution containing conductive particles and water glass is applied to the face panel surface, and a solution containing anti-reflection particles and water glass is applied thereon. By performing the batch firing, the transparent conductive film and the antireflection film are formed at the same time, and the transparent conductive film and the antireflection film are in a mixed state without a boundary, and the electric conduction between the transparent antireflection film surface and the transparent conductive film is performed. Is electrically conductive.

According to a ninth aspect of the present invention, the method for applying the solution containing the conductive particles and the water glass and the method for applying the solution containing the antireflection particles and the water glass are spin coating methods. It is characterized by.

[0021]

FIG. 1 is a front view and a side view of a color CRT 10 according to a first embodiment of the present invention. In the figure, 11 is a face panel, 12 is a protective tape, 13 is an explosion-proof band, and 14 is a conductive tape. FIG. 2 is FIG.
FIG. 2 is an enlarged sectional view of a portion A of the color CRT. In the figure, 15 is a transparent conductive film, 16 is an antireflection film, and 17 is a schematic representation of a mixed portion of a transparent conductive film and an antireflection film.

Next, a method of forming a laminated film on the face panel surface of the color cathode ray tube 10 according to the first embodiment of the present invention will be described.
The glass for the face panel 11 has a transmittance of approximately 57% at a wavelength of 546 nm at a thickness of 10.16 mm.

First, in order to form the transparent conductive film 15, a water glass solution having a silica: ruthenium oxide weight ratio of 1:10 and silica and ruthenium oxide fine particles uniformly dispersed therein is applied to a face panel by spin coating. 11 Apply to outer surface. At this time, the average particle size of the ruthenium oxide fine particles is suitably 50 nm or less. The coating film thickness is determined by the desired transmittance and sheet resistance. In this embodiment, the coating film thickness is adjusted to 50% as a result of adjusting the transmittance to 87% and the sheet resistance to 5000Ω / □. became. Unlike the related art, the coating film is not yet fired at this stage.

Next, in order to form the anti-reflection film 16 on the transparent conductive film 15 before firing, a solution containing silica and water glass is applied by spin coating. Here, it is a feature of the present invention that the water glass is used as a common component of the transparent conductive film 15 and the antireflection film 16 which is not present in the prior art. The reason will be described in the next firing step.

In this case, it is preferable to use water glass having the same characteristics. This is because the components of the transparent conductive film 15 and the antireflection film 16 are mutually diffused through the water glass, as described later. However, if the characteristics of both the water glasses are the same, the mutual diffusion is more reliably performed. is there. The coating method is preferably a spin coating method. As the application conditions in the spin coating method, it is preferable to lower the viscosity and concentration of the material so that the antireflection film 16 has a higher number of rotations at the time of application and shake-off than the transparent conductive film 15. .
This is to make the antireflection film 16 as thin as possible at the shoulder portion of the face panel 11. By doing so, conduction between the conductive tape 14 and the transparent conductive film 15 becomes more reliable.

Next, the face panel 11 to which these two types of coating were applied was baked at 450 ° C. for 30 minutes to obtain the transparent conductive film 1.
5 and the antireflection film 16 are fixed to the panel surface. Simultaneous firing of the transparent conductive film 15 and the antireflection film 16 in this manner is a feature of the present invention not found in the prior art. As described above, since the transparent conductive film 15 and the antireflection film 16 contain water glass, which is a common component, when both coating films are simultaneously fired, the interface between the transparent conductive film 15 and the antireflection film 16 melts. Both components are mixed via water glass.

Further, at the time of baking, the release path of the gas is formed in the antireflection film 16 due to the release of the water glass decomposition gas from the lower transparent conductive film 15. It also functions as a conductive path reaching the surface of the prevention film 16. Then, when the conductive tape 14 is stuck on the surface of the antireflection film 16, electrical continuity between the transparent conductive film 15 and the conductive tape 14 is secured. This function is the same as that of the terminal pad 55 in the conventional color cathode ray tube 50.
Therefore, the terminal pad 55 of the conventional color CRT 50 is not necessary in the color CRT 10 of the present invention. This is a characteristic of the color cathode ray tube 10 of the present invention.

After a black matrix, a phosphor film, and a metal back film are formed on the inner surface of the face panel 11 on which the above-mentioned laminated films 15 and 16 are formed, a shadow mask, an inner shield, a getter, and the like are attached to the inside. Seal with graphite coated funnel. Further, an electron gun is mounted on the neck to evacuate the inside. Further, a protective tape 12 and an explosion-proof band 13 for safety are wound around the outer periphery of the face panel 11. After winding the explosion-proof band 13, a conductive tape 14 is attached between the anti-reflection film 16 on the surface of the face panel 11 and the explosion-proof band 13, as shown in FIG. Finally, the deflection yoke is mounted, and final adjustment is performed to complete the color cathode ray tube 10 of the first embodiment of the present invention.

Since the color cathode ray tube 10 of the first embodiment of the present invention shown in FIG. 1 is of type 17, the long side of the face panel 11 is about 370 mm and the length of the conductive tape 14 (along the long side of the face panel 11). Length) is 150 mm, and the width of the conductive tape 14 is 30 mm. Therefore, (length of conductive tape 14 / long side of face panel 11) = 150
/370=40.5%.

Next, with reference to FIG. 3, the dependence of the alternating electric field on the size of the conductive tape and the position of application thereof (experimental results of the inventor) will be described. In the figure, 3A to 3G indicate the types of experiments. In the figure, reference numeral 31 denotes a conductive tape stuck to the long side of the face panel, 32 denotes a conductive tape stuck to the short side of the face panel, and 33 denotes a terminal pad. Common to this experiment, the color CRT is 17 type,
The sheet resistance of the transparent conductive film is 5000Ω / □, and 10
000Ω / □. The values below the figures indicate the values of the alternating electric field, a) when the sheet resistance is 5000Ω / □, and b) when the sheet resistance is 10,000Ω / □.

The following can be understood from the experimental results.
(1) When the sheet resistance is 5000Ω / □, it is sufficient if the conductive tape is applied only near the center of the long side of the face panel or only near the center of the short side. At that time, the length of the conductive tape along the side of the face panel is 50 mm
Is enough. At this time, the ratio of the conductive tape to the long side of the face panel was 50 mm / 370 mm = 13.5%, and the ratio of the conductive tape to the short side of the face panel was 50 mm / 280 m.
m = 17.9%. The method of sticking to only two opposing sides is advantageous for production efficiency and automation.

(2) When the sheet resistance is 10000 Ω / □, it is sufficient that the conductive tape is applied only near the center of the long side of the face panel. Then, of the conductive tape,
A length of 150 mm along the side of the face panel is sufficient. There is no experiment in which a 150 mm conductive tape was applied only to the short side of the face panel.
/ M or less is estimated. At this time, the ratio of the conductive tape to the long side of the face panel is 150 mm / 370 m.
m = 40.5%, and the ratio of the conductive tape to the short side of the face panel is 150 mm / 280 mm = 53.6%. However, even for conductive tapes of the same length, the effect of reducing the effect is greater when applied to the long side, and the effect is greater when applied to the center of the side.

(3) Since the presence or absence of the terminal pad 33 has almost no effect on the value of the alternating electric field, no terminal pad is required.

Next, the dependency of the alternating electric field on the sheet resistance of the transparent conductive film 15 will be described with reference to FIG. The condition of the conductive tape 14 in this experiment is shown in 3G of FIG.
The conductive tape 14 having a length of 150 mm is used for the face panel 11.
It is pasted near the center of the long side. The figure shows that the conductive tape is 1
It can be seen that at 50 mm, the sheet resistance is allowed up to about 15000 Ω / □. This value is three to five times the conventional value.

[0035]

As described above, in the color CRT of the present invention, a solution containing conductive particles and water glass is applied to the face panel surface, and a solution containing anti-reflection particles and water glass is applied thereon. The transparent conductive film and the antireflection film were simultaneously formed by firing both at once, so that electrical conduction with the transparent conductive film could be obtained directly from the surface of the antireflection film.

As a result, the sheet resistance required for the transparent conductive film could be approximately 3 to 5 times that of the conventional color cathode ray tube. In addition, terminal pads, which are necessary in the conventional color cathode ray tube, are no longer necessary. Thus, a color cathode ray tube having a sufficient alternating electric field shielding effect was realized at low cost.

[Brief description of the drawings]

FIG. 1 is a front view and a side view of a color CRT according to a first embodiment of the present invention.

FIG. 2 is a partially enlarged cross-sectional view of the color CRT according to the first embodiment of the present invention.

FIG. 3 is a front view showing the size of the conductive tape of the color cathode ray tube of the present invention, the sticking position, and the alternating electric field.

FIG. 4 is a graph showing the relationship between the alternating electric field and the sheet resistance of the color cathode ray tube of the present invention.

FIG. 5 is a front view and a side view of a conventional color CRT.

FIG. 6 is a partially enlarged sectional view of a conventional color CRT.

[Explanation of symbols]

 10, 50 Color cathode ray tube 11, 51 Face panel 12, 52 Protective tape 13, 53 Explosion-proof band 14, 54 Conductive tape 15, 56 Transparent conductive film 16, 57 Antireflective film 17 Mixed part of transparent conductive film and antireflective film 31 Conductive tape on long side of face panel 32 Conductive tape on short side of face panel 33, 55 Terminal pad

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2K009 AA04 AA10 BB02 CC03 CC09 DD02 EE03 5C028 AA01 AA09 AA10 5C032 DD04 DE01 DE05 DG01 DG02 5G435 AA00 AA16 BB02 CC12 GG33 HH03 HH12 KK05

Claims (9)

[Claims] 1. A color cathode ray tube having a laminated film in which at least a transparent conductive film and an antireflection film are laminated in this order on a face panel surface, wherein the conductive tape directly adhered to the antireflection film surface comprises the transparent conductive film. A color cathode-ray tube characterized by ensuring electrical continuity between the protection band and the explosion-proof band. 2. The color cathode ray tube according to claim 1, wherein the transparent conductive film contains a film containing ruthenium oxide as conductive particles, a film containing silver as conductive particles, or palladium as conductive particles. A color cathode ray tube comprising a film or a film containing a silver-palladium alloy as conductive particles. 3. The color cathode ray tube according to claim 1, wherein the antireflection film is a film containing silica as a low refractive index material. 4. The color cathode ray tube according to claim 1, wherein said conductive tape is an aluminum tape or a copper tape. 5. The color cathode ray tube according to claim 1, wherein the transparent conductive film has a sheet resistance of 15,000 Ω / □ or less. 6. The color cathode ray tube according to claim 1, wherein the conductive tape is applied only near a center of a long side of the face panel. 7. The color cathode ray tube according to claim 1, wherein the conductive tape is applied only near a center of a short side of the face panel. 8. The transparent conductive film by applying a solution containing conductive particles and water glass to the face panel surface, applying a solution containing anti-reflection particles and water glass on the face panel, and firing both at once. And the anti-reflection film are simultaneously formed, the transparent conductive film and the anti-reflection film are in a mixed state without a boundary, and electrical conduction from the anti-reflection film surface to the transparent conductive film is possible. Manufacturing method of color CRT. 9. The method for manufacturing a color cathode ray tube according to claim 8, wherein the method of applying the solution containing the conductive particles and the water glass, and the method of applying the solution containing the antireflection particles and the water glass,
A method for producing a color cathode ray tube, which is a spin coating method.