JPH11204056A - Color cathode-ray tube and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode ray tube of high luminance and high contrast without increasing the manufacturing cost. SOLUTION: This cathode-ray tube is constituted of the inner face of the face panel 1 and a light selective absorption layer 3 having the same optical properties is formed between only the space between neighboring red-emitting and blue emitting phosphor layers 4R, 4B of red emitting, green-emitting, and blue-emitting phosphor layers 4R, 4G, 4B formed on the inner face of the face panel. A fine cobalt silicate particle pigment is dispersed in the light selective absorption layer 3 and the concentration of the pigment is so set as to suppress the light transmittance in 500-600 m wavelength region to 70% of that in 380-500 nm wavelength region and in 600-730 nm wavelength region.

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 having a light selective absorption layer provided between an inner surface of a face panel and a phosphor layer, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Various methods have been proposed for improving the contrast of a color cathode ray tube. For example, as a commonly used method, a face panel holding a phosphor layer on the inner surface has a light transmittance of 40 to 40%.
There is a method using dark glass of about 45%. In this case, the external light is absorbed by the dark glass, so that the contrast can be improved. However, at the same time, the light emitted from the phosphor screen is also absorbed by the dark glass, so that the luminance is reduced. Also, a method of using a phosphor with a pigment for the phosphor layer is well known. In this method, when the pigment concentration increases, a part of the light emitted from the phosphor layer is absorbed by the pigment, and the luminance also decreases. .

As a method for achieving high contrast while maintaining brightness, tint glass having a relatively high light transmittance (about 50 to 60% light transmittance) is used for a face panel, and three-color fluorescent light is applied to the outer surface thereof. A method of providing a light selective absorption film having a high light transmittance for body light emission and effectively reducing external light reflection has also been considered. This light selective absorption film is usually
It is composed of an inorganic or organic pigment or dye and a binder, but if the light transmittance of the face panel is to be further increased in order to achieve higher luminance, these pigments or dyes are to be suppressed in order to suppress an increase in external light reflection. The concentration needs to be increased. However, when the pigment or dye concentration is increased, the film strength is reduced, and the film is damaged or peeled off, not only deteriorating the appearance but also affecting the image quality.

[0004] As another method, a light selective absorption layer containing a pigment of the same color as the emission color of each color phosphor is provided between the inner surface of the face panel and the three color phosphor layers. Are provided. In this method, since a filter layer made of a light selective absorption layer is provided on the inner surface of the face panel, a decrease in film strength in a high pigment concentration region as seen when the light selective absorption film is provided on the outer surface of the face panel described above. It is not affected and is a very effective method for high brightness and high contrast when combined with a high transmittance face panel.However, in order to provide a filter layer for each phosphor layer for each color, Need to be formed by photoengraving, and then each color phosphor layer must be formed by photoengraving. Therefore, the number of processes is twice as large as in the past, and significant additional equipment is required, resulting in significantly higher manufacturing costs. Disadvantage.

On the other hand, as a filter layer on the inner surface of a face panel which does not require pattern formation, Japanese Patent Application Laid-Open No.
Japanese Patent Application Laid-Open Publication No. H11-163,086 discloses that a single light selective absorption layer made of a mixed component of a blue pigment and a red pigment or a single violet pigment is formed on the entire inner surface of a face panel. By the way, also in the case of this method, as in the case of providing a single light selective absorption film on the outer surface of the face panel, when the light transmittance of the face panel is further increased in order to achieve higher luminance, the increase in external light reflection is reduced. In order to suppress this, it is necessary to increase the concentration of the pigment constituting the light selective absorption layer. In that case, in the method disclosed in Japanese Patent Application Laid-Open No. 7-240156, the luminance performance is impaired by greatly reducing the phosphor emission as mentioned in the publication. When the pigment concentration is set to a low level as shown in the examples of the publication to avoid this, a sufficient contrast cannot be obtained in combination with a face panel having a high transmittance. That is, it is difficult to improve both the luminance performance and the contrast performance by this method.

[0006]

As described above, as a measure for achieving high contrast, the method of using dark glass for the face panel or the method of using a phosphor with pigment reduces the luminance, and the face panel has a disadvantage. In the method in which a light selective absorption film is provided on the outer surface of the above, the film strength is reduced when the concentration of the pigment or dye is increased. Further, in the method of providing a filter layer composed of a light selective absorption layer containing a pigment of the same color as the emission color of each color phosphor between each inner surface of the face panel and each color phosphor layer, manufacturing There is a problem that the cost is significantly increased, and the method of providing a single light selective absorption layer on the entire inner surface of the face panel has a problem that the luminance performance is greatly impaired when the pigment concentration is increased.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a color cathode ray tube having a high brightness and a high contrast without a significant increase in manufacturing cost. This is the purpose of 1. It is a second object of the present invention to provide a manufacturing method capable of easily realizing such a color cathode ray tube.

[0008]

SUMMARY OF THE INVENTION A color cathode ray tube according to the present invention has an inner surface of a face panel and a fluorescent material of two specific colors among three color phosphor layers of red, green and blue formed on the inner surface of the face panel. A light selective absorption layer having the same optical characteristics is provided only between the body layer.

Further, in the light selective absorption layer of the color cathode ray tube according to the present invention, the light transmittance of the phosphor layers of two specific colors for light emission is higher than the light transmittance of the remaining one color phosphor layer for light emission. It has optical characteristics.

Further, in the color cathode ray tube according to the present invention, the phosphor layers provided with the light selective absorption layer are red and blue phosphor layers.

Further, the light selective absorption layer of the color cathode ray tube according to the present invention has a light transmittance in a wavelength range of 500 nm to 600 nm of 380 nm to 500 nm and 600 nm to 600 nm.
The ratio to the light transmittance in the wavelength range of 730 nm is 70% or less.

Further, in the method of manufacturing a color cathode ray tube according to the present invention, a step of forming a light selective absorption layer having a single optical characteristic on the entire inner surface of the face panel; Selectively removing the light selective absorption layer of the phosphor layer other than the region where the two specific color phosphor layers are formed; and forming the two specific color phosphor layers on the remaining light selective absorption layer. And a step of forming a phosphor layer of the remaining one color on the inner surface of the face panel from which the light selective absorption layer has been removed.

In the method of manufacturing a color cathode ray tube according to the present invention, the light selective absorption layer contains an inorganic pigment as a light absorbing substance.

Further, in the method of manufacturing a color cathode ray tube according to the present invention, the inorganic pigment is cobalt silicate.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A color cathode ray tube and a method of manufacturing the same according to the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is a partially enlarged sectional view of a fluorescent screen of a color cathode ray tube according to Embodiment 1 of the present invention. A black light absorbing layer 2 and red, green, and blue three-color phosphor layers 4R, 4G, and 4B are provided on the inner surface of the face panel 1 as in the conventional phosphor screen. The case is different from the conventional case in that the light selective absorption layer 3 having the same optical characteristics is provided only between the inner surface of the face panel 1 and the red and blue phosphor layers 4R and 4B.

Next, a method of manufacturing a color cathode ray tube according to Embodiment 1 of the present invention will be described with reference to FIG. First, as shown in FIG.
The black light absorbing layer 2 patterned by the reversal developing method is formed. Next, a suspension of the following composition 1 in which a fine particle cobalt silicate pigment (average particle diameter: 0.05 μm) is dispersed is applied by spin coating, dried, and then subjected to light selective absorption as shown in FIG. 2 (B). The layer 3 is formed. (Composition 1) Cobalt silicate pigment 6.2 to 12.8% by weight Polycarboxylic acid-based dispersant 3.0% by weight Polyvinyl alcohol 3.0% by weight Sodium dichromate 0.3% by weight Water balance

Next, the light selective absorption layer 3 at the position where the red and blue phosphor layers are to be formed is sequentially exposed and cured through the mask used when forming the black light absorption layer 2, and then washed with water to develop a green color. The light selective absorption layer 3 at the position where the phosphor layer is formed is selectively removed, and as shown in FIG. 2C, the light selective absorption is performed only at the position where the red and blue phosphor layers are formed. The layer 3 is formed. Next, as shown in FIG. 2 (D), red, green and blue 3
The color phosphor layers 4R, 4G, and 4B are formed. At this time, the red and blue phosphor layers 4R and 4B are formed on the light selective absorption layer 3, and the green phosphor layer 4G is formed on the region where the light selective absorption layer 3 is removed.

FIG. 3 is a diagram for explaining the optical characteristics of the light selective absorption layer 3 of the color cathode ray tube obtained in the first embodiment. In the figure, B indicates the spectral distribution of the relative emission intensity of the blue phosphor layer 4B, which has a main spectral wavelength at about 450 nm. Similarly, G and R indicate the spectral distributions of the relative emission intensities of the green and red phosphor layers 4G and 4R, respectively, at 530 nm and 625 nm, respectively.
Has a main spectral wavelength. In addition, K, L, M and N indicate that the concentration of the cobalt silicate pigment is 6.2% by weight, 7.3%.
The spectral transmittance distributions of the light selective absorption layer 3 when the weight percentage is 9.6 weight% and 12.8 weight% are shown, respectively. Cobalt silicate pigments have an absorption bottom around 500 nm to 600 nm. In the first embodiment, the concentration of the cobalt silicate pigment is changed in four steps, and the average light transmittance in the wavelength range of 500 nm to 600 nm is 380 nm to 500 nm and 6%.
The ratio to the average light transmittance in the wavelength range of 00 nm to 730 nm was changed.

[0020]

[Table 1]

Table 1 summarizes the transmittance characteristics of the light selective absorption layer 3 obtained by changing the concentration of the cobalt silicate pigment. When the concentration of the cobalt silicate pigment is 9.6% by weight,
Of the average light transmittance in the wavelength range of 500 nm to 600 nm,
380 nm to 500 nm and 600 nm to 730 nm
It can be seen that the ratio to the average light transmittance in the wavelength range is about 70%, the ratio is higher than 70% at lower concentrations, and lower than 70% at higher concentrations.

[0022]

[Table 2]

Table 2 shows the evaluation of the characteristics of the color cathode ray tube obtained in the first embodiment assuming that the conventional product is 100. In the first embodiment, the face panel 1 is changed from a conventional low transmittance glass (transmittance of 40%) to a high transmittance glass (transmittance of 75%) in order to increase the luminance, and the face panel 1 is easily compared. A neutral filter having the following composition 2 was provided on the outer surface of the face panel by a well-known sol-gel method, and the rate of improvement in luminance was adjusted to 20%. (Composition 2) Carbon graphite 0.07 to 0.10% by weight Silicon alkoxide 2.0% by weight Water 10.0% by weight Ethanol balance

From Table 2, it can be seen that the light selective absorption layer 3 has a thickness of 500 nm or more.
380 nm-average light transmittance in the wavelength range of 600 nm
When the ratio to the average light transmittance in the wavelength region of 500 nm and 600 nm to 730 nm is higher than about 70% (test tubes 1 and 2), the luminance performance is maintained, but the external light reflection is significantly increased, and the contrast performance is reduced. It turns out that it cannot be maintained. On the other hand, when this ratio is about 70% or less (test tubes 3 and 4), it is recognized that the luminance performance is improved and the contrast performance is maintained or improved. That is, if the above-mentioned ratio is set to about 70% or less, both the luminance and the contrast performance can be improved.

According to the manufacturing method of the first embodiment,
Since the light selective absorption layer 3 provided for the red and blue phosphor layers 4R and 4B is the same, only one application step is required, and the light source is moved to the corresponding phosphor layer exposure position during exposure. By providing a mechanism that allows the light selective absorption layer 3 to be formed in a single exposure step with a single exposure facility. That is, exposure can be performed at the light source position corresponding to the first color, and then the light source can be moved to the light source position corresponding to the second color to perform exposure of the second color. After exposing the light selective absorption layer 3 at the position corresponding to the red and blue phosphor layers 4R and 4B in this way, the light selective absorption at the position corresponding to the green phosphor layer 4G is performed in the washing and developing step. By washing and removing the layer 3, the light selective absorption layer 3 can be formed only at the positions where the red and blue phosphor layers 4R and 4B are formed. Therefore, as compared with the method of providing a filter layer composed of a light selective absorption layer containing a pigment of the same color as the emission color of each color phosphor layer for each color phosphor layer, the manufacturing process is simple and does not require significant additional equipment. In addition, an increase in manufacturing cost can be suppressed low.

In the first embodiment, cobalt silicate is mentioned as an example of the light absorbing material used for the light selective absorption layer 3 provided between the inner surface of the face panel 1 and the red and blue phosphor layers 4R and 4B. However, this light absorbing substance is not limited to cobalt silicate alone, and it goes without saying that pigments having similar properties can be used. Examples of pigments having such properties include ultramarine blue violet and cobalt phosphate. And cobalt phosphate containing lithium.

Embodiment 2 FIG. Next, a case where the light selective absorption layer 3 is provided only for the blue and green phosphor layers 4B and 4G will be described. The phosphor screen structure and the phosphor screen forming step are basically the same as those of the first embodiment except that the phosphor layer on which the light selective absorption layer 3 is to be provided is different and the composition of the light selective absorption layer 3 is different. Since they are the same, detailed description is omitted.

In the second embodiment, the blue and green phosphor layers 4 B, 4 B, 4 B, 4 B, 4 B,
For G, a light selective absorption layer 3 was formed. (Composition 3) Ultramarine 5.3-11.6% by weight Polycarboxylic acid-based dispersant 3.0% by weight Polyvinyl alcohol 3.0% by weight Sodium dichromate 0.3% by weight Water balance

In the second embodiment, similarly to the first embodiment, high transmittance glass (having a transmittance of 75
%) And a neutral filter containing an appropriate concentration of carbon graphite was provided on the outer surface of the face panel, and the luminance improvement rate was adjusted to 20% for evaluation.

[0030]

[Table 3]

Table 3 shows the evaluation of the characteristics of the color cathode ray tube obtained in Embodiment 2 with the conventional product being 100. FIG. 4 is a diagram for explaining the optical characteristics of the light selective absorption layer 3 of the color cathode ray tube obtained in the second embodiment, and corresponds to FIG. 3 for the first embodiment. In FIG. 4, P, Q, R and S indicate that the concentration of ultramarine is 5.3% by weight, 6.8% by weight, 8.4% by weight and 1%.
The spectral transmittance distribution of the light selective absorption layer 3 when the content is 1.6% by weight is shown. From Table 3, it can be seen that both the luminance and the contrast performance can be improved in the density range where the density of ultramarine blue is 8.4% by weight or more (test tubes 3 and 4). In FIGS. 3 and 4, the critical spectral transmittance spectrum capable of improving the luminance performance while maintaining the contrast performance, that is, 9.6% by weight of the cobalt silicate pigment and 8.4% by weight of the ultramarine blue. It can be seen from the comparison of spectra that the bottom of the ultramarine blue spectrum is deeper. That is, in order to obtain an effect equivalent to that of the first embodiment according to the second embodiment, the light selective absorption layer 3 having a darker color than that of the first embodiment must be provided. This is because light in the red region, which is removed by the ultramarine spectrum, has lower luminous efficiency than light in the green region, which is removed by the spectrum of cobalt silicate, and therefore the effect of reducing external light reflection is low. is there.

In the second embodiment, ultramarine is mentioned as an example of the light absorbing substance used for the light selective absorption layer 3 provided between the inner surface of the face panel 1 and the blue and green phosphor layers 4B and 4G. This light-absorbing substance is not limited to ultramarine blue, and it goes without saying that any pigment having similar properties can be used. Examples of pigments having such properties include cobalt aluminate. .

Embodiment 3 Next, a case where the light selective absorption layer 3 is provided only for the red and green phosphor layers 4R and 4G will be described. The phosphor screen structure and the phosphor screen forming step are basically the same as those of the first embodiment except that the phosphor layer on which the light selective absorption layer 3 is to be provided is different and the composition of the light selective absorption layer 3 is different. Since they are the same, detailed description is omitted.

In the third embodiment, red and green phosphor layers 4R, 4R, 4C are used by using a suspension having the following composition 4 containing inorganic fine yellow pigment (particle diameter: 0.012 μm).
For G, a light selective absorption layer 3 was formed. (Composition 4) Yellow pigment 3.5-6.6% by weight Polycarboxylic acid dispersant 3.0% by weight Polyvinyl alcohol 3.0% by weight Sodium dichromate 0.3% by weight Water balance

In the third embodiment, the first and second embodiments are also used.
Similarly to the above, a high transmittance glass (75% transmittance) is used for the face panel 1 and a neutral filter containing a suitable concentration of carbon graphite is provided on the outer surface of the face panel 1 to improve the luminance improvement rate by 20%. %.

[0036]

[Table 4]

Table 4 shows the evaluation of the characteristics of the color cathode ray tube obtained in Embodiment 3 assuming that the conventional product is 100. FIG. 5 is a view for explaining the optical characteristics of the light selective absorption layer 3 of the color cathode ray tube obtained in the third embodiment, and corresponds to FIG. 3 for the first embodiment. In FIG. 5, T, U, V and W represent the light selective absorption layer 3 when the concentration of the yellow pigment is 3.5% by weight, 4.7% by weight, 5.8% by weight and 6.6% by weight. Are shown. Table 4 shows that both the luminance and the contrast performance can be improved in the concentration range (test tubes 3 and 4) where the concentration of the yellow pigment is 5.8% by weight or more. 3 and 5, the limit spectral transmittance spectrum capable of improving the luminance performance while maintaining the contrast performance, that is, 9.6% by weight in the cobalt silicate pigment
And the spectrum of 5.8% by weight of the yellow pigment, it can be seen that the bottom of the spectrum of the yellow pigment is deeper. That is, in order to obtain an effect equivalent to that of the first embodiment by the third embodiment, the first embodiment
Must be provided with a light selective absorption layer 3 of a darker color. This is similar to the case of the second embodiment, compared to the light in the green region that is removed by the spectrum of cobalt silicate.
This is because light in the blue region, which is removed by the spectrum of the yellow pigment, has lower luminosity and therefore has a lower effect of reducing external light reflection.

In the second and third embodiments, the light selective absorption layer 3 of a dark color required for improving the luminance performance while maintaining or improving the contrast performance.
Is provided, the face surface of the cathode ray tube has a slight color tone defined by each light selective absorption layer 3. That is, in the case of the second embodiment, the face surface is slightly bluish, and in the case of the third embodiment, it is slightly yellowish. On the other hand, in order to express pure black which is important for the display performance of the cathode ray tube, it is desirable that the face surface be as achromatic as possible. Therefore, the method of Embodiment 1 in which the light selective absorption layer 3 is provided on the red and blue phosphor layers 4R and 4B which do not require the dark light selective absorption layer 3, is most desirable.
In the case where the body color of the face surface does not matter, the luminance performance can be improved while maintaining or improving the contrast performance by the methods of the second and third embodiments.

[0039]

According to the color cathode ray tube of the present invention, the inner surface of the face panel and the phosphor layers of two specific colors of the three color phosphor layers of red, green and blue formed on the inner surface of the face panel are provided. Since the light selective absorption layer having the same optical characteristics is provided only between the two, a color cathode ray tube having high brightness and high contrast can be provided without a significant increase in manufacturing cost.

In the color cathode ray tube according to the present invention, the light selective absorption layer has a light transmittance for the light emission of the phosphor layers of two specific colors, and a light transmittance for the light emission of the remaining one color phosphor layer. Since it has optical characteristics higher than the ratio, it is possible to effectively reduce external light reflection without significantly impairing the light emission of the phosphor layer, so that high luminance and high contrast can be effectively achieved.

Further, according to the color cathode ray tube of the present invention, since the phosphor layers provided with the light selective absorption layer are the red and blue phosphor layers, the external light reflection component in the green wavelength region having high visibility can be reduced. Thus, the effect of reducing external light reflection can be enhanced. Also, since a dark light selective absorption layer is not required, the body color of the face surface can be maintained achromatic, which is suitable for expressing pure black, which is important for the display performance of a cathode ray tube. .

According to the color cathode ray tube of the present invention, the light selective absorption layer has a light transmittance in a wavelength range of 500 nm to 600 nm of 380 nm to 500 nm and 60 nm.
Since the ratio to the light transmittance in the wavelength range of 0 nm to 730 nm is 70% or less, the effect of reducing external light reflection can be increased, and both the luminance and the contrast performance can be obtained even when a face panel having a high transmittance is used. Can be reliably improved.

Further, according to the method of manufacturing a color cathode ray tube according to the present invention, a step of forming a light selective absorption layer having a single optical characteristic on the entire inner surface of the face panel; Selectively removing the light selective absorption layer of the color phosphor layer other than the region where the specific two color phosphor layers are formed; and forming the specific two color phosphor layer on the remaining light selective absorption layer. And a step of forming a phosphor layer of the remaining one color on the inner surface of the face panel from which the light selective absorption layer has been removed, so that the manufacturing process is simple and there is no need to add significant equipment. A color cathode ray tube having high luminance and high contrast can be obtained without a significant increase in manufacturing cost.

Further, according to the method for manufacturing a color cathode ray tube according to the present invention, since the light selective absorption layer contains an inorganic pigment as a light absorbing material, the light selective absorption layer receives the light during the manufacturing process of the color cathode ray tube. A color cathode ray tube which is stable to a heat treatment temperature of 500 to 500 ° C., is stable to electron beams and X-rays received during the operation of the color cathode ray tube, and has a desired light selective absorption characteristic. be able to.

According to the method of manufacturing a color cathode ray tube according to the present invention, since the inorganic pigment is cobalt silicate, a light selective absorption layer having desired optical characteristics can be easily formed.

[Brief description of the drawings]

FIG. 1 is a partially enlarged cross-sectional view of a phosphor screen of a color cathode ray tube according to Embodiment 1 of the present invention.

FIG. 2 is a process chart showing a method for manufacturing a color cathode ray tube according to Embodiment 1 of the present invention.

FIG. 3 is a diagram showing optical characteristics of a light selective absorption layer of the color cathode ray tube obtained in the first embodiment of the present invention.

FIG. 4 is a diagram showing optical characteristics of a light selective absorption layer of a color cathode ray tube obtained in Embodiment 2 of the present invention.

FIG. 5 is a diagram showing optical characteristics of a light selective absorption layer of a color cathode ray tube obtained in Embodiment 3 of the present invention.

[Explanation of symbols]

1 face panel, 2 black light absorbing layer, 3
Light selective absorption layer, 4R red phosphor layer, 4G green phosphor layer, 4B blue phosphor layer.

Claims (7)

[Claims] 1. The same optical characteristics are provided only between an inner surface of a face panel and a phosphor layer of two specific colors among red, green, and blue phosphor layers formed on the inner surface of the face panel. A color cathode ray tube comprising a light selective absorption layer having the same. 2. The light selective absorption layer according to claim 1, wherein the light transmittance of the phosphor layer of two specific colors is higher than that of the remaining one phosphor layer. The color cathode ray tube according to claim 1. 3. The color cathode ray tube according to claim 1, wherein the phosphor layer provided with the light selective absorption layer is a red and blue phosphor layer. 4. The light selective absorption layer has a thickness of 500 nm to 600 n.
The ratio of the light transmittance in the wavelength range of m to the light transmittance in the wavelength ranges of 380 nm to 500 nm and 600 nm to 730 nm is 70% or less. The color cathode ray tube as described. 5. A step of forming a light selective absorption layer having a single optical property on the entire inner surface of the face panel;
A step of selectively removing the light selective absorption layer other than the region where the two specific color phosphor layers are formed from the green and blue three color phosphor layers; A step of forming a phosphor layer of two specific colors and a step of forming a phosphor layer of one remaining color on the inner surface of the face panel from which the light selective absorption layer has been removed. A method for manufacturing a cathode ray tube. 6. The method for producing a color cathode ray tube according to claim 5, wherein the light selective absorption layer contains an inorganic pigment as a light absorbing substance. 7. The method for producing a color cathode ray tube according to claim 6, wherein the inorganic pigment is cobalt silicate.