JP2675696B2 - Method of forming antistatic film for cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION This invention, antistatic of shadow Kyokusenkan
The present invention relates to a film forming method .

[0002]

2. Description of the Related Art In recent years, the voltage applied to the phosphor screen of a cathode ray tube, that is, the accelerating voltage of an electron beam, has increased with the increase in size of color cathode ray tubes and the improvement in brightness performance and focus performance. For example, in a conventional 21-inch class color cathode ray tube, the voltage applied to the phosphor screen is 2
The voltage was about 5 to 27 KV, but in recent large-sized color cathode ray tubes of 30 inches or more, a high voltage of 30 to 34 KV is applied.

Therefore, especially when the power supply of the television set is turned on and off, the outer surface of the face plate portion of the color cathode ray tube is charged up, and dust in the air adheres to the outer surface of the face plate portion. Contamination is likely to be conspicuous, and as a result, it has been a cause of deteriorating the luminance performance and the like of the color cathode ray tube.

Further, a discharge phenomenon may occur when a viewer approaches the outer surface of the face plate portion that has been charged up, and the viewer may feel uncomfortable.

FIG. 7 is a graph showing changes in the surface potential of the face plate portion when the power is turned on and off. A characteristic curve L in the drawing is a change characteristic of the surface potential when the power is turned on, and the characteristic curve is also shown. L1 is the change characteristic of the surface potential when the power is off.

As described above, in order to eliminate the charge-up phenomenon on the outer surface of the face plate portion, a smooth transparent conductive film for preventing electrification is formed on the outer surface of the face plate portion so that the charge escapes to the ground side. Antistatic-treated cathode ray tubes have come into use in recent years.

FIG. 6 is a view for explaining the antistatic mechanism of the antistatic cathode ray tube, and 6 is an electron gun (not shown).
A neck portion, a deflection yoke, a funnel portion, a face plate portion, a high voltage button 5 and a deflection power source via a lead wire 7a.
The electron gun is connected to a driving power source via a lead wire 6a, and the high voltage button 5 is connected to a high voltage power source via a lead wire 5a.

In the cathode ray tube having the above-mentioned structure, the face plate portion 4 is prevented from being charged by forming the smooth transparent conductive film 1 for preventing charging , especially on the outer surface of the face plate portion 4.

Next, the operation of the above configuration will be described. First, an electron beam emitted from an electron gun built in the neck portion 6 is electromagnetically deflected by the deflection yoke 7, and a high voltage is applied to the fluorescent surface provided on the inner surface of the face plate portion 4 via the high pressure button 5. To accelerate the electron beam,
As the phosphor screen was excited to emit light by energy by taking out the optical output.

In the above-mentioned antistatic treatment type cathode ray tube 3, as shown in FIG.
As shown in, a smooth transparent conductive film 1 is formed on the outer surface of the face plate portion 4, and the transparent conductive film 1 is grounded so that the charge is always released to the ground to prevent the charge-up. There is no adverse effect such as dust adhesion.

In the antistatic cathode ray tube 3, the metal explosion-proof band 8 wound around the side wall of the face plate portion 4 and the transparent conductive film 1 are electrically connected by the conductive tape 12, and the metal explosion-proof band 8 is formed. It is configured to be connected to the ground 10a via the ground wire 10 which is hooked on the mounting ear 9 of.

Here, if the smooth transparent conductive film 1 as shown in FIG. 6 is not formed on the outer surface of the face plate portion 4, the high voltage applied to the inner fluorescent surface of the face plate portion 4 is applied. As a result, the outer surface of the face plate portion 4 is charged up as described above, and it is needless to say that adverse effects such as dust adhesion may occur.

Characteristic curves M and M shown by broken lines in FIG.
FIG. 1 is a diagram showing a potential change characteristic of the outer surface of the face plate portion 4 when the power source of the antistatic cathode ray tube 3 is turned on and off, and it can be seen that the charge-up is significantly smaller than that of the conventional one. .

Since the smooth transparent conductive film 1 formed on the surface of the face plate portion 4 is required to have a certain degree of hardness and adhesiveness that poses no practical problems, silica (SiO 2) is generally used.
₂ ) Forming a system film.

As an example of the method for forming the silica-based smooth transparent conductive film 1, as functional groups, --OH group, --OH
An alcohol solution of silicon (Si) alkoxide having an OR group or the like is applied uniformly and evenly on the outer surface of the face plate portion 4 of the cathode ray tube by a spin coating method or the like, and then baked at a relatively low temperature (for example, 100 ° C. or lower). The method of processing is adopted.

The smooth transparent conductive film 1 formed by such a method is porous and has a silanol group (≡S).
Since it has i-OH), it can adsorb moisture in the air to reduce the surface resistance.

However, such a conventional transparent conductive film 1 is used.
When subjected to baking treatment at high temperature,
After the H group is eliminated, since also eliminates moisture incorporate in a porous, surface resistance is increased, since not be obtained conductive predetermined exactly, low temperature baking is required, therefore, the strength of the film Not very strong.

Further, when it is left in a dry environment for a long time, the water content in the porous material escapes and the surface resistance value increases with time.
Ri, also, once the moisture takes disconnect from the porous in,
Again, conductivity is not restored because it is difficult to penetrate.

[0019] Thus, conventional transparent conductive film 1 had a significant drawback in terms of temporal stability of the film strength and surface resistivity.

In order to improve such a difficulty, it has been attempted to impart conductivity by binding a metal atom such as zirconium (Zr) to the alkoxide structure in the coating solution, but it is expected to be greatly improved. I couldn't do that.

As means for fundamentally solving these disadvantages, fine particles of tin oxide (SnO ₂ ) or indium oxide (In ₂ O ₃ ) are mixed and dispersed in the alcohol solution of silicon alkoxide as a conductive filler. , Trace amount of phosphorus (P) for imparting semiconductor properties
Alternatively, there is a method in which a coating liquid containing antimony (Sb) is uniformly applied to the outer surface of the face plate portion 4 of the cathode ray tube and the baking treatment is performed at a relatively high temperature (for example, 100 to 200 ° C.).

According to the above method, a smooth transparent conductive film having a strong film strength and a surface resistance value which does not change with time under any environment can be obtained.

However, in the color cathode ray tube which has been subjected to the antistatic treatment by forming the smooth transparent conductive film whose surface resistance value does not change with time as described above, the image quality of recent color television receivers can be improved. strong demand and to, by coloring the transparent conductive film, the request to improve the contrast and emission color of the color cathode ray tube, were those not cope adequately.

Therefore, there is a strong demand for high image quality of color television receivers and the need to color this transparent conductive film.
More, improve the contrast and light-emitting color tone of the color cathode-ray tube
In order to meet such demands , a color cathode ray tube has been developed in which a photoselective absorption film having an antistatic function is used as an antistatic conductive film .

This light selective absorption film is used as an antistatic conductive film.
A color cathode ray tube that uses a conventional coating liquid to obtain a transparent conductive film as a base material is mixed with an organic or inorganic dye or pigment to form a light selective absorption coating liquid, It is applied and formed on the outer surface of the face plate portion of the color cathode ray tube by the same spin coating method or the like.

FIG. 3 shows the constitution of Yoko light selective absorption film with a color cathode ray tube, other than shown to light selective absorption film 2 in the figure,
The same configuration as the conventional antistatic treatment cathode ray tube 3 shown in FIG.

FIG. 5 is a diagram for explaining the optical characteristics of the light selective absorption film 2. A characteristic curve B in the drawing is a blue-emitting sulfide-based phosphor on the phosphor screen of the color cathode ray tube, for example, with silver. The relative emission intensity spectrum distribution characteristics of the active zinc sulfide phosphor (ZnS: Ag) are shown, and the main spectrum wavelength is about 450 nm.

Characteristic curve G shows the relative emission intensity spectrum distribution characteristic of a green-emitting sulfide-based phosphor, for example, gold, copper, and aluminum co-activated zinc sulfide phosphor (ZnS: Au, Cu, AI). It has a dominant spectral wavelength at about 535 nm. Similarly, the characteristic curve R shows the relative emission intensity spectrum distribution characteristic of a red-emitting rare earth-based phosphor, for example, a europium-activated yttrium oxysulfide phosphor (Y ₂ O ₂ S: Eu), and the main spectrum wavelength is about 626 nm. Have.

Characteristic curves II and III are shown in the face plate portion 4 where the fluorescent surface of the color cathode ray tube is formed.
The characteristic curve II is a clear type with a spectral transmittance of about 85% in the visible light range, and the characteristic curve II is a characteristic curve.
III shows the spectral transmittance distribution of the tint type face plate portion 4 of 50%.

The lower the spectral transmittance of the face plate portion 4, the more disadvantageous the fluorescent screen luminance performance of the color cathode ray tube.
This is clear from the relationship with the relative emission intensity spectrum distribution of the B, G, and R phosphors. However, external light incident on the fluorescent surface of the color cathode ray tube can be effectively removed, which is advantageous in contrast performance. For this reason, in recent color television receivers, the tint type face plate portion 4 is often used from the viewpoint of importance of image quality.

A characteristic curve I in the figure shows an example of the spectral transmittance distribution characteristic of the light selective absorption film 2 provided to improve the contrast performance, and the main spectrum of the spectral distribution of the relative emission intensities of G and R. of wavelength between 535～626Nm, when the portion close to the main spectrum wavelength is an absorption peak a of the light selective absorption film 2 this, to become disadvantageous on brightness performance of the color cathode ray tube, the half-width and the like of the absorption band Taking this into consideration, the absorption peak A of the absorption band is usually placed within the range of 570 to 610 nm.

This is because the light of the wavelength in this range coincides with the region where the human eye has a relatively high visibility, so that the external light (white light)
This is because it is preferable in terms of contrast performance that the light in this region among the components can be absorbed and removed.

That is, regarding the optical characteristics of the conventional light selective absorption film 2, the visual sensitivity of the human eye is relatively high, and the light flux emitted from the phosphor screen is minimally affected by 570 to 61.
The absorption peak A of the absorption band is placed in the range of 0 nm so as to effectively absorb outside light and improve the contrast performance while maintaining the brightness performance of the phosphor screen.

It is very important to select an organic or inorganic dye or pigment having such optical characteristics.
Characteristic curve I is an example in which an absorption peak A in the absorption band is provided at 580 nm.

As described above , in the light selective absorption film , the organic or inorganic dye or pigment mixed in the base paint has a relatively broad optical light absorption characteristic, and therefore, among the light emitted from the fluorescent surface, for example, tails of the long wavelength side of the main spectrum wavelength green light emission, and in Rukoto sub-peak portion of the short wavelength side of the main spectrum wavelength red emission is absorbed by the light selective absorption film, at the same time the improvement of the light emission color it can be carried out.

[0036] Figure 4 is a partially enlarged cross-sectional view of the faceplate of the color cathode ray tube having a light selective absorption film, light selective absorption film 2 formed on the external surface surface of the faceplate portion 4 Porous Dye particles or molecules 13 in the silica-based film 14
Are formed in a dispersed form.

[0037]

[Problems to be Solved by the Invention] Conventional antistatic conductive material
When forming a film, even if it is a transparent conductive film, an optical selection is performed.
Even in the case of selective absorption film, it was applied to the face plate part.
The coating liquid was heated by infrared rays using an electric heating furnace .
Therefore , the heat efficiency is poor, which requires huge power costs.
Was. Further, since faceplate portion is a curved surface, the heating becomes uneven, and Tsu disadvantage mower that quality antistatic Yoshirubeden film can not be uniform.

[0038] The present invention has been made to solve the above problems, an inexpensive manufacturing cost, yet providing an antistatic film forming method of the cathode ray tube quality can <br/> uniform To aim.

[0039]

To achieve the above object, according to an aspect of, the present invention is coated with a sheet re <br/> mosquito system coating liquid on the outer surface of the faceplate portion and thus bake hardenability to the radiofrequency thermal This
By this, a porous antistatic conductive film is formed .

[0040]

SUMMARY OF] According to the present invention, more baking hard silica-based coating liquid that has been applied to the outer table <br/> surface of the faceplate portion in the radiofrequency thermal
To heat the inside of the face plate part,
The thermal efficiency is good, and the manufacturing cost such as the power cost can be significantly reduced as compared with the conventional baking process using an electric heating furnace.
Furthermore, since it is possible to uniformly heat, antistatic Yoshirubedenmaku <br/> quality of that Do uniform over the entire film.

[0041]

An embodiment of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. 1 is a high frequency heating for explaining an embodiment of the present invention.
It is the schematic which shows an apparatus .

[0042] In the figure, 15 is a high frequency generator order to generate a high-frequency, 16 generated by the high frequency generator 15
Waveguide 11 the waveguide 16 for guiding the high frequency obtained by
A color cathode ray tube installed in the opening portion of the other end of the.

Next, the operation of the heating device will be described with reference to FIGS. 1 and 3. The high frequency generated by the high frequency generator 15 is applied to the outer surface of the conductive film for antistatic by the waveguide 16.
Silica coating liquid is guided to the full Esupureto portion 4 which is coated comprising. Therefore, the power of the high frequency generator 15 is gradually increased so that the outer surface temperature of the face plate portion 4 becomes 10
By heating to 0 to 200 ° C., silica
System coating liquid is kicked <br/> baking the face plate portion as a conductive film for preventing charging.

Next, an antistatic conductive material by high frequency heating
The experimental results of the relationship between baking time and the film strength of the film are shown in Table 1.

[0045]

[Table 1]

As an experimental condition, a face plate portion coated with an antistatic conductive film was cut into pieces of about 5 cm × 5 cm, and a household microwave oven having a working frequency of several MHz to several hundred MHz was used as a high frequency generator. Using. Processing time is 0,3,8,10 minutes, piece temperature is 25,70,
The temperature was 113 and 140 ° C.

As is clear from the results shown in Table 1, the outer surface of the piece rose to 140 ° C. and the JI
The pencil hardness based on S was 5H, and the film was hardened to the extent that scratches were not made up to 20 times in the abrasion test with a plastic eraser. Furthermore, the film strength was constant over the entire outer surface of the piece, and the film was uniformly cured.

By performing high-frequency heating as described above, efficient and uniform heating can be performed, the manufacturing cost is lower than that of conventional electric furnace heating, and further, the antistatic conductor is used.
It became possible to make the quality of the electrolytic film uniform over the entire film.

[0049] EXAMPLE 2 FIG. 2 is a schematic diagram showing an apparatus of a large number, form of arranging in parallel a radiofrequency NetsuSo location shown in FIG.

As shown in the figure, the film does not serve as an antistatic conductive film.
That silica coating liquid color cathode ray tube which is coated successively under the waveguide high frequency Ru guided <br/> by the belt conveyor 17, by conveying, as in Example 1, less production cost, and quality has become possible Rukoto obtain a uniform antistatic Yoshirubeden film over the entire film.

[0051] Particularly, in Example 2, since the color cathode ray tube 11 on the belt co Nbeya 17 has a configuration in which are sequentially conveyed, baked Tsukesho management time in each waveguide is short,
Once having passed through all of the waveguide, previously adjusted to the transport rate and the cumulative amount of heat as silica based coating solution of the faceplate outer table surface can be sufficiently baked as antistatic Yoshirubedenmaku.

As described above, antistatic conductive material using high frequency heating
It has been described baking treatment of the membrane, and an antistatic conductive film
As a result, the same effect can be obtained for both the transparent conductive film and the light selective absorption film .

[0053] Further, not containing a conductive filler or a dye porous silica-based anti-glare processing Hodoko Sumono, and porous silica-based antistatic treatment type anti-glare processing Hodoko Sumono, further, optical even with <br/> to shall provide a low reflection film according to the interference film, it is of course possible to obtain the same effect.

[0054]

As is evident from the foregoing description, according to the present invention, since using a high-frequency heating in baking of antistatic Yoshirubedenmaku can manufacturing cost is inexpensive, and the quality uniform.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a high-frequency heating device for explaining an embodiment of the present invention.

2 is a schematic diagram showing an apparatus arranged in parallel radiofrequency NetsuSo location of Figure 1 for illustrating another embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a color cathode ray tube using a light selective absorption film as an antistatic conductive film .

FIG. 4 is a partially enlarged cross-sectional view of a face plate portion of a color cathode ray tube including a light selective absorption film .

FIG. 5 is a diagram showing optical characteristics of a light selective absorption film.

FIG. 6 is a diagram showing a configuration of a conventional antistatic color cathode ray tube.

FIG. 7 is a diagram showing changes in the surface potential of the face plate portion when the power source of the color cathode ray tube is turned on and off.

[Explanation of symbols]

11 Color cathode ray tube with light selective absorption film 15 High frequency generator 16 Waveguide 17 Belt conveyor

Claims (1)

(57) [Claims] 1. A silica-based material on the outer surface of the face plate portion.
Along with applying the coating liquid, it is baked and cured by high frequency heating,
A method for forming an antistatic film for a cathode ray tube , characterized in that a porous antistatic conductive film is formed .