JPH0676754A - Color cathode-ray tube phosphor screen and formation thereof - Google Patents

Abstract

PURPOSE:To provide a color cathode-ray tube phosphor screen and a manufacturing method thereof, by which a phosphor film of excellent brightness and of high contrast can be provided at low cost. CONSTITUTION:In a color cathode-ray tube phosphor screen in which a phosphor screen containing at least phosphor and pigment is formed on a face plate 22, the phosphor screen comprises a high reflection grain layer 24 formed in the side of the face plate 22 and a phosphor grain layer 27 formed in the side of an electron gun. The density of high reflection grains 23 is higher than that of phosphor grains 26, and the average grain size of the high reflection grains is smaller than that of the phosphor grains 26. At the time of manufacturing the phosphor screen, a slurry, for which a small amount of the high reflection grains 23 are mixed in the phosphor grains 26, is rotated and applied to the inner surface of the panel of a color cathode-ray tube, and the high reflection grain layer 24 is separated from the phosphor grain layer 27 by the difference in the density between the high reflection grains 23 and the phosphor grains 26 at the time of drying the slurry.

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 phosphor screen and a method for forming the same, and more particularly, to improve the brightness and contrast of the phosphor screen, a high reflection function particle layer is provided on the face plate side of an electron gun. The present invention relates to a color cathode-ray tube fluorescent screen having a fluorescent surface on which a fluorescent material layer is disposed, and a method for forming the same.

[0002]

2. Description of the Related Art Conventionally, in order to improve the brightness and contrast of a color cathode ray tube, after forming a red, blue, and green pigment filter layer for each picture element that emits red, blue, and green,
There has been proposed a so-called filter method, which is a method of forming different phosphor layers for emitting respective colors.

FIG. 6 is a cross-sectional view showing one picture element portion of a phosphor screen manufactured by the filter method.

In FIG. 6, 50 is a face plate of a color cathode ray tube, 51 is a black matrix, 52 is a pigment filter layer, 53 is a phosphor layer, and 54 is an aluminum film. The face plate 50 is divided by the black matrix 51, and one of the pixels constitutes one pixel. This one pixel is the face plate 50.
To pigment filter layer 52, phosphor layer 53, aluminum film 54
Are arranged in sequence.

In the above structure, first, in order to form a filter layer 52 of one color, for example, red, a well-known photolithography means (slurry coating of photosensitizer and filter particles → exposure) is applied to a portion corresponding to a red pixel. → Development) to form a red pigment filter layer 52, and then, for the formation of a blue filter layer 52, a blue pigment is formed on a portion corresponding to a blue pixel by using a well-known photolithography means. Form the filter layer 52 and then the green filter layer 5
In order to form No. 2, the green pigment filter layer 52 is formed in the portion corresponding to the green pixel by using the well-known photolithography means (slurry application of photosensitive agent and filter particles → exposure → development). Following this, the red phosphor layer 5
In order to form 3, the red phosphor layer 53 is formed in the portion corresponding to the red pixel by using the well-known photolithography means, and then, for forming the blue phosphor layer 53,
A blue phosphor layer 53 is formed on the portion corresponding to the blue pixel using the same well-known photolithography means, and finally, in order to form the green phosphor layer 53, a portion corresponding to the green pixel is formed. Similarly, a green phosphor layer 53 is formed by using a well-known photolithography means. As described above, in the filter method, the photolithography means needs to be repeatedly performed twice for each color, for a total of six times, and when the pigment filter layer 52 and the phosphor layer 53 are formed. Not only was the manufacturing cost increased, but it was also difficult to achieve practically.

Therefore, in order to improve the above-mentioned points, a method of coating the surface of the phosphor particles with pigment fine particles and laminating the coated phosphor particles to form a phosphor film to improve the contrast, A so-called coating method is also known.

FIG. 7 is a sectional view showing one picture element portion of the phosphor screen manufactured by the coating method.

In FIG. 7, 55 is a phosphor particle, 56 is a pigment particle, and the same constituent elements as those shown in FIG. 6 are denoted by the same reference numerals.

The surface of the relatively large phosphor particles 55 is appropriately coated with small pigment particles 56, and the pigment particles 56 are coated with these phosphor particles 55.
Are laminated on the face plate 50, and the aluminum film 54 is arranged on the electron gun side to form a fluorescent film.

According to this coating method, it is possible to manufacture by simply coating the phosphor particles 55 of each color with the pigment particles 56 and then stacking the phosphor particles 55 of each color corresponding to the pixel portion of each color. The cost is low and the feasibility is excellent.

[0011]

However, in this coating method, when the concentration of the pigment particles to be coated is increased in order to improve the contrast of the phosphor screen, light emission in the phosphor film mainly occurs on the electron gun side. Since the light obtained by the light emission is emitted from the fluorescent film after being repeatedly reflected and transmitted inside the fluorescent film, there is a new problem that the brightness of the fluorescent film decreases. .

The present invention eliminates the above-mentioned problems, and an object of the present invention is to provide a color cathode ray tube phosphor screen capable of obtaining a phosphor film having excellent brightness and high contrast at a low cost, and its manufacture. To provide a method.

[0013]

To achieve the above object, the present invention provides a color cathode ray tube fluorescent screen in which a fluorescent screen containing at least a fluorescent substance and a pigment is formed on a face plate. It is composed of a highly reflective particle layer formed on the face plate side and a phosphor particle layer formed on the electron gun side, and the high reflective particles have a higher density than the phosphor particles, and the average particle size of the phosphor particles. A first means having a smaller particle size.

In order to achieve the above-mentioned object, the present invention provides a phosphor slurry of each color having a particle size higher than that of the phosphor and smaller than the average particle size of the phosphor particles. Mixing reflective particles to form a slurry of each color,
The slurry of each color is applied to the inner surface of the panel of the color cathode-ray tube for each color, a shadow mask is fitted after the application of the slurry and exposed, and after the exposure, the shadow mask is removed and development is performed to sequentially form a slurry pattern of each color. And a second means for obtaining a fluorescent screen.

[0015]

According to the first means, since the fluorescent surface has the highly reflective particle layer arranged on the face plate side and the fluorescent particle layer arranged on the electron gun side, the electrons emitted from the electron gun are The beam reaches the highly reflective particle layer through the phosphor particle layer. In this case, since, for example, a bismuth particle layer having a high electron beam reflection efficiency is used as the highly reflective particle layer, the reflection of the electron beam by the bismuth particle layer improves the brightness of the phosphor screen. Further, by coating the bismuth particles with pigment particles, the contrast of the phosphor screen can be improved.

According to the second means, highly reflective particles, such as bismuth particles, in which the phosphor particles of each color have a particle density higher than that of the phosphor and smaller than the average particle diameter of the phosphor particles. To form a slurry of each color, and the slurry is applied to the inner surface of the panel of the color CRT. At the time of this coating, the highly reflective particles (bismuth particles) first settle on the inner surface of the panel, and then the phosphor particles start to settle. Therefore, the highly reflective particle layer is arranged on the face plate side of the fluorescent surface. As a result, the phosphor particle layer is arranged on the electron gun side, and the phosphor screen thus obtained has improved brightness and contrast as described above.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an example of the overall structure of a color cathode ray tube using a phosphor screen according to the present invention.

In FIG. 1, 1 is a panel portion, 2 is a funnel portion, 3 is a neck portion, 4 is a fluorescent screen, 5 is a shadow mask, 6 is a magnetic shield, 7 is a deflection yoke, 8 is a purity adjusting magnet, and 9 is. A center beam static convergence adjustment magnet, 10 is a side beam static convergence adjustment magnet, 11 is an electron gun, Bc is a center beam, and Bs is a side beam.

In the convergence adjustment (static convergence) of such a color cathode ray tube, first, the convergence of the two side beams Bs and Bs is taken, and then the center beam Bc and the convergence point of the side beam Bs are concentrated. ing.

FIG. 2 is a partial block diagram showing details of an example of the configuration of the fluorescent screen 4 and the shadow mask 5.

In FIG. 2, 12 is a light-absorbing strip, 13 is a red phosphor strip, 14 is a green phosphor strip, 15 is a blue phosphor strip, 16 is a slit through hole, and 17 is a bridge portion. In addition, the same components as those shown in FIG. 1 are denoted by the same reference numerals.

The fluorescent surface 4 formed on the inner surface of the panel portion 1 has a light-absorbing strip 1 extending vertically without a break.
A plurality of red phosphor strips 13 and green phosphor strips that are arranged in the horizontal direction and have different emission colors between the light absorption strips 12 and extend continuously throughout the vertical direction. 14, a large number of blue phosphor strips 15 are arranged in a fixed order in the horizontal direction. Further, the shadow mask 5 having a curved surface corresponding to the inner surface of the panel portion 1 is arranged face-to-face with the fluorescent surface 4, and each color fluorescent fine strip 13 extends seamlessly over the entire vertical direction. Through 15
Corresponding to the above, the slit strip through hole 1 which is elongated in the vertical direction and is formed in a large number in the vertical direction through the bridge portion 17
6 are provided, and these slit line through holes 16 are arranged in a row at a predetermined pitch in the horizontal direction.

FIG. 3 is a partial configuration diagram showing details of another example of the configuration of the phosphor screen 4.

In FIG. 3, 18 is a red phosphor fine dot, 1
Reference numeral 9 is a green phosphor fine dot, 20 is a blue phosphor fine dot, and 21 is a light absorbing film. Other than that, the same components as those shown in FIG.

The phosphor screen 4 is surrounded by the red phosphor fine dots 18, the green phosphor fine dots 19, the blue phosphor fine dots 20, and the respective phosphor fine dots 18 to 20 arranged in a delta shape. It is composed of a buried light absorption film 21.

The shadow mask 5 is made of a steel plate material and an amber material having a small coefficient of thermal expansion, and is further coated with a material that suppresses thermal expansion, such as bismuth. Is also known. In addition, instead of the slit-shaped through hole 16, there is also one in which a round through hole is used.

Next, FIG. 4 shows an embodiment of the phosphor screen according to the present invention, and is a sectional view showing the structure of one picture element portion on the phosphor screen.

In FIG. 4, 22 is a face plate of a color cathode ray tube, 23 is a bismuth oxide particle forming a highly reflective particle, 24 is a bismuth oxide particle layer forming a highly reflective particle layer, and 25 is a surface of the bismuth oxide particle 23. Coated pigment particles, 26 is a phosphor particle, 27 is a phosphor particle layer, 28 is an aluminum film, and 29 is a black matrix.

The face plate 22 is divided by the black matrix 29, and one of the divided ones constitutes one pixel. This one pixel is coated with pigment particles 25 on the face plate 22. The bismuth oxide particle layer 24, the phosphor particle layer 27, and the aluminum film 28 thus formed are sequentially stacked.

An example of the manufacturing process of the phosphor screen having the above-mentioned structure is as follows.

For example, a black matrix 29 is formed by a known method on the face plate 22 on the inner surface of the panel of a color cathode ray tube (horizontal pitch: 0.75 mm) having a fluorescent screen size of 59 cm, and then the average particle diameter of 8 is formed on the inner surface of the panel.
The slurry obtained by mixing 10 μm of the bismuth oxide particles having an average particle diameter of 2 μm in a weight ratio with the green phosphor particles of μm is spin-coated, and after the applied slurry is dried, a shadow mask is fitted to perform exposure, and exposure is performed. After that, the shadow mask is removed, development is performed with pure water at 40 ° C., and drying is performed to form a green slurry pattern. Subsequently, the bismuth oxide particles having an average particle diameter of 8.5 μm and the bismuth oxide particles having an average particle diameter of 2.5 μm coated with a blue pigment (cobalt aluminate) at a weight ratio of 0.8 wt% are prepared. A slurry obtained by mixing 10 wt% in a weight ratio is spin coated, and after the coated slurry is dried, a shadow mask is fitted to perform exposure, and after the exposure, the shadow mask is removed and development is performed with pure water at 40 ° C. Further, it is dried to form a blue slurry pattern. Then, the red bismuth oxide particles having an average particle size of 8.7 μm and the bismuth oxide particles having an average particle size of 2.8 μm coated with red pigment (red iron oxide) at a weight ratio of 0.8 wt% were mixed in a weight ratio. The slurry obtained by mixing 10 wt% was spin-coated, and after the slurry was dried, a shadow mask was fitted to perform exposure, and after the exposure, the shadow mask was removed and development was performed with pure water at 40 ° C., followed by drying. By doing so, a red slurry pattern is formed.

The phosphor screen having the green, blue, and red slurry patterns thus obtained has a specific gravity (3.9%) of the phosphor particles 26 when the slurry is dried after spin coating.
To 4.8), bismuth oxide particles 23 having a specific gravity (7.2) higher than that of bismuth oxide are first deposited on the face plate 22 to form a bismuth oxide particle layer 24, and then phosphor particles 26 are applied to the face plate. Since the phosphor particle layer 27 is formed by depositing on the surface 22, the phosphor surface having the bismuth oxide particle layer 24 on the face plate 22 side and the phosphor particle layer 27 on the electron gun 11 side is obtained. To be

After the fluorescent screen is formed, the color cathode ray tube is manufactured by using the same process as a normal manufacturing process.

As described above, according to this embodiment, when the color cathode ray tube is used, the electron beam emitted from the electron gun 11 is reflected by the bismuth oxide particle layer 24, so that the brightness of the phosphor screen is improved, Further, the pigment particles 25 coated on the bismuth oxide particles 23 can improve the contrast of the phosphor screen.

FIG. 5 shows another embodiment of the phosphor screen according to the present invention, which is also a sectional view showing the structure of one picture element portion on the phosphor screen.

In FIG. 5, 30 is a small diameter bismuth oxide particle, 31 is a large diameter bismuth oxide particle, and
The same components as those shown in FIG. 4 are designated by the same reference numerals.

The small-diameter bismuth oxide particles 30 are
Pigment particles 25 are coated on the surface, and small-sized bismuth oxide particles 3 coated with pigment particles 24
0 forms the bismuth oxide particle layer 24. On the other hand, the large-diameter bismuth oxide particles 31 are not coated with the pigment particles 25 and are mixed in the phosphor particles 26 to form the phosphor particle layer 27 together with them.

An example of the manufacturing process of the phosphor screen having the above structure is as follows.

For example, a black matrix 29 is formed by a known method on the face plate 22 on the inner surface of the panel of a color cathode ray tube (horizontal pitch 0.75 mm) having a phosphor screen size of 59 cm, and then green phosphor particles having an average particle size of 8 μm. In addition, the average particle size is 2 μm (small diameter) at a weight ratio of 80 wt.
%, Average particle size 8 μm (large diameter) 20 wt%
% Bismuth oxide particles containing 10% by weight
A mixed slurry is prepared, and the slurry obtained here is spin-coated on the inner surface of the panel. Next, the applied slurry is dried, and then a shadow mask is fitted and exposure is performed. After the exposure, the shadow mask is removed and the shadow mask is removed.
By developing with pure water at 0 ° C. and further drying, a green stripe-shaped slurry pattern is formed. Next, the blue phosphor particles having an average particle diameter of 8.5 μm and those having an average particle diameter of 2.3 μm (small diameter) coated with 0.8 wt% of a blue pigment (cobalt aluminate) are used. Bismuth oxide particles containing 90% by weight and an average particle size of 8.5 μm (large diameter) at 10% by weight,
A slurry mixed in a weight ratio of 10 wt% is prepared, and the slurry obtained here is spin-coated on the inner surface of the panel. Next, the applied slurry is dried, and then a shadow mask is fitted to perform exposure, and after the exposure, the shadow mask is removed, development is performed with pure water at 40 ° C., and further drying is performed to form a blue stripe shape. Form a slurry pattern. Further, the red phosphor particles having an average particle diameter of 8.7 μm and the particles having an average particle diameter of 2.3 μm (small diameter) are in a weight ratio of 0.1.
Bismuth oxide particles containing 90% by weight of a red pigment (red iron oxide) coated in an amount of 8% by weight and 10% by weight of an average particle size of 8.5 μm (large diameter) in a weight ratio of 10% by weight. A mixed slurry is prepared, and the slurry obtained here is spin-coated on the inner surface of the panel. Next, the applied slurry is dried, and then a shadow mask is fitted to perform exposure, and after the exposure, the shadow mask is removed and development is performed with pure water at 40 ° C.
A red stripe-shaped slurry pattern is formed by drying.

The green, blue, and red stripe-shaped slurry patterns thus obtained have the same phosphor screen as in the above-described Examples, when the slurry was spin-coated and then dried.
First, the small diameter bismuth oxide particles 30 are first deposited on the face plate 22 to form the bismuth oxide particle layer 24, and then the large diameter bismuth oxide particles 31 and the phosphor particles 26 are deposited on the face plate 22. Since the phosphor particle layer 27 is formed by deposition, a phosphor screen having the bismuth oxide particle layer 24 on the face plate 22 side and the phosphor particle layer 27 on the electron gun 11 side is obtained.

Also in this embodiment, after the phosphor screen is formed, a color cathode ray tube is manufactured by using the same process as a normal manufacturing process.

As described above, also in this embodiment, when the color cathode ray tube is used, the electron beam emitted from the electron gun 11 is reflected by the bismuth oxide particle layer 24, so that the brightness of the phosphor screen is improved and the electrons are emitted. It is difficult for the lines to reach the face plate 22, and the level of browning of the face glass is improved. Further, the pigment particles 25 coated on the bismuth oxide particles 23 can improve the contrast of the phosphor screen.

The brightness, contrast, manufacturing cost, and browning of the face glass obtained by each of the above examples are compared with the phosphor screen of the coating method which has been widely used conventionally. First of
Shown in the table.

[0045]

[Table 1]

As is clear from this table, the phosphor screen according to the present embodiment has the effect that the brightness and contrast can be considerably improved at substantially the same cost as the phosphor screen of the coating system which has been widely used conventionally. There is also a secondary effect that the browning characteristics of the face glass are also improved.

In each of the above-mentioned embodiments, the most suitable bismuth particles are used as the highly reflective particles, but the present invention is limited to those using bismuth particles as the highly reflective particles. But particles made of other similar materials, such as rare earth oxides or sulfides,
Zirconium, molybdenum, tungsten, lead alone,
Alternatively, oxides or compounds thereof can be used. Further, although the embodiment has been described with respect to the color cathode ray tube, it goes without saying that the application can be performed more easily if it is applied to a cathode ray tube in which a fluorescent film is produced by sedimentation coating like a projection tube.

When comparing the density of the highly reflective particles and the density of the phosphor particles, it is preferable that the difference is large,
In the case where sufficient brightness and contrast can be obtained, such as a small color cathode-ray tube, if highly reflective particles with a density not much different from the density of the phosphor particles are used, the light emission of the phosphor pattern of each color becomes uniform, The texture of the display screen becomes smooth.

[0049]

As described above, according to the present invention, the fluorescent surface is composed of the highly reflective particle layer 24 formed on the face plate 22 side and the fluorescent particle layer 26 formed on the electron gun 11 side. By doing so, the brightness of the fluorescent screen can be improved by the reflection of the electron beam by the highly reflective particle layer 24. Further, by coating the high reflection particle layer 24 with the pigment particles 25, it is possible to improve the contrast of the phosphor screen.

[Brief description of drawings]

FIG. 1 is a cross-sectional configuration diagram showing an example of the overall structure of a color CRT using a phosphor screen according to the present invention.

FIG. 2 is a partial configuration diagram showing details of an example of a configuration of a fluorescent screen and a shadow mask of the color cathode ray tube shown in FIG.

FIG. 3 is a partial configuration diagram showing details of another example of the configuration of the fluorescent screen of the color CRT shown in FIG.

FIG. 4 shows an embodiment of a phosphor screen according to the present invention, and is a cross-sectional view showing the structure of one picture element portion on the phosphor screen.

FIG. 5 shows another embodiment of the phosphor screen according to the present invention, and is a cross-sectional view showing the structure of one picture element portion on the phosphor screen.

FIG. 6 is a cross-sectional view showing one picture element portion of a phosphor screen manufactured by a conventional filter method.

FIG. 7 is a cross-sectional view showing one pixel portion of a phosphor screen manufactured by a conventional coating method.

[Explanation of symbols]

1 Panel Part 2 Funnel Part 3 Neck Part 4 Fluorescent Surface 5 Shadow Mask 6 Magnetic Shield 7 Deflection Yoke 8 Purity Adjusting Magnet 9 Center Beam Static Convergence Adjusting Magnet 10 Side Beam Static Convergence Adjusting Magnet, 11 Electron Gun 12 Light Absorption Fine Strips 13 Red Fine phosphor strip 14 Green fine phosphor strip 15 Blue fine phosphor strip 16 Slit strip Through hole 17 Bridge part 18 Red fine phosphor spot 19 Green fine phosphor spot 20 Blue fine phosphor spot 21 Light absorption film 22 Color cathode ray tube Face plate 23 Bismuth oxide particles forming highly reflective particles 24 Bismuth oxide particle layer forming highly reflective particle layers 25 Pigment particles coated on the surface of bismuth oxide particles 23 Phosphor particles 27 Phosphor particle layers 28 Aluminum film 29 Bu Click matrix 30 bismuth oxide particles of bismuth oxide particles 31 large diameter of the small diameter

Claims (6)

[Claims] 1. A color cathode ray tube fluorescent screen in which a fluorescent screen containing at least a fluorescent substance and a pigment is formed on a face plate, the fluorescent screen being on a highly reflective particle layer formed on the face plate side and on an electron gun side. And a high-reflectance particle having a higher density than the phosphor particles and having a particle size smaller than the average particle size of the phosphor particles. CRT fluorescent screen. 2. The color CRT fluorescent screen according to claim 1, wherein the highly reflective particles are bismuth oxide particles. 3. The fluorescent screen of a color cathode ray tube according to claim 1, wherein the highly reflective particles are coated with pigment particles on their surfaces. 4. A slurry of each color is formed by mixing highly reflective particles having a density higher than that of the phosphor and having a particle diameter smaller than the average particle diameter of the phosphor particles in the phosphor slurry of each color. , The slurry of each color is applied to the inner surface of the panel of the color CRT for each color, a shadow mask is fitted and exposed after the application of the slurry, and after the exposure, the shadow mask is removed and development is performed to sequentially form a slurry pattern of each color. A method for forming a phosphor screen of a color cathode ray tube, characterized in that the phosphor screen is formed to obtain a phosphor screen. 5. The method for forming a phosphor screen of a color cathode ray tube according to claim 4, wherein the highly reflective particles are bismuth oxide particles. 6. The method for forming a fluorescent screen of a color cathode ray tube according to claim 4, wherein the high-reflecting particles are coated with pigment particles on their surfaces.