JPH06310050A - Cathode-ray tube and formation of phosphor screen thereof - Google Patents

Abstract

PURPOSE:To provide a bright and high contrast phosphor film free from emission nonuniformity at the low cost by providing phosphor particles or high reflection particles of large average particle size in the side of an electron gun, and by providing the phosphor particles or high reflection particles of small average particle size in the side of a face plate. CONSTITUTION:A face plate 22 is divided by a black matrix 2, and each divided part forms a picture element. For one picture element, a high reflection particle layer 24 of small average particle size, for which the face plate 22, is coated with a pigment 25, is provided, and a phosphor particle layer 27 of large average particle size, and an aluminum film 28 are layered thereon in the order. A phosphor layer of small average particle size may be formed instead of the high reflection particle layer 24.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube and a method for forming a fluorescent screen thereof, and more particularly, in order to improve the brightness and contrast of the fluorescent screen, a high reflection function particle layer is provided on the face plate side and the electron gun side The present invention relates to a cathode ray tube having a phosphor screen on which phosphor layers are arranged, and a method for forming the phosphor screen.

[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,
A method of forming a phosphor layer of each color that emits each color, that is, a so-called filter method has been proposed.

FIG. 7 is a cross-sectional view showing one picture element portion of the fluorescent screen manufactured by the filter method.

In FIG. 7, 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 2, the green pigment filter layer 52 is formed on the portion corresponding to the green pixel by using the same well-known photolithography means. 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. 8 is a sectional view showing one picture element portion of the phosphor screen manufactured by the coating method.

In FIG. 8, 55 is a phosphor particle, 56 is a pigment particle, and the same constituent elements as those shown in FIG. 7 are designated 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. . Further, each color phosphor layer has a different emission luminance, and in particular, a phosphor layer having a high luminous efficiency, for example, a green phosphor layer, has uneven scattering due to reflection and transmission inside the film, and uneven emission on the entire phosphor screen. There is a problem that occurs.

The present invention is intended to eliminate the above-mentioned problems, and an object thereof is to obtain a fluorescent film which is excellent in brightness, has no uneven light emission on the screen, is smooth, and has a high contrast. An object of the present invention is to provide a possible cathode ray tube and a fluorescent screen forming method thereof.

[0013]

In order to achieve the above object, the present invention provides a phosphor screen including a phosphor picture element pattern on a face plate on the inner surface of a panel and an electron gun for emitting an electron beam to the phosphor screen. In the cathode ray tube comprising at least, the phosphor screen 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 particle is the phosphor particle. A phosphor particle layer having a first phosphor picture element pattern having a higher density and a smaller average particle size, and particularly a phosphor picture element pattern having a high luminous efficiency, both the face plate side and the electron gun side are phosphor particle layers. And a second phosphor picture element pattern whose average particle size is smaller in the particle layer formed on the face plate side than in the particle layer formed on the electron gun side.
Equipped with the means.

In order to achieve the above object, the present invention provides a phosphor slurry having a particle size higher than that of the phosphor particles in the slurry and smaller than the average particle size of the phosphor particles. Reflective particles are mixed to form a slurry of a predetermined color, and particularly for phosphor slurries having a high luminous efficiency, phosphor particles having different average particle diameters, for example, large-diameter phosphor particles having a small specific gravity and small particles having a large specific gravity are used. The second means is provided in which the phosphor particles are mixed to form the phosphor slurry, and the slurry is applied to the inner surface of the panel of the cathode ray tube to form a slurry pattern to obtain the phosphor screen.

[0015]

According to the first means, the phosphor picture element pattern on the phosphor screen has the highly reflective particle layer arranged on the face plate side and the phosphor particle layer arranged on the electron gun side.
The electron beam emitted from the electron gun 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. For a phosphor pixel pattern having a particularly high luminous efficiency, a phosphor particle layer having a large specific gravity and a small average particle size is arranged on the face plate side, and a phosphor particle having a small specific gravity and a large average particle size is arranged on the electron gun side. Since the layers are arranged, the electron beam emitted from the electron gun reaches the small particle layer through the large particle layer. In this case, since the phosphor layer made of a substance having a large electron beam scattering property is used as the small particle layer, the light emission of the fluorescent surface becomes uniform due to the electron beam scattering property of the small particle layer, which causes uneven emission. It is possible to obtain a smooth fluorescent film.

According to the second means, highly reflective particles, such as bismuth, having a particle size higher than that of the phosphor particles in the slurry and smaller than the average particle size of the phosphor particles in the phosphor slurry. A slurry of a predetermined color is formed by mixing particles, and particularly for a phosphor having a high luminous efficiency, a plurality of phosphor particles having different average particle diameters are mixed to form the phosphor slurry, and this slurry is It is applied to the inner surface of the cathode ray tube panel. Then, 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, so that the highly reflective particle layer is arranged on the face plate side of the fluorescent surface. Then, the phosphor particle layer is arranged on the electron gun side. In the case of the phosphor having a high luminous efficiency, small particles having a large specific gravity and a small average particle diameter first settle on the inner surface of the panel, and then large particles having a small specific gravity and a large average particle diameter settle. Therefore, in this phosphor, a small particle layer is arranged on the face plate side, and a large particle layer is arranged on the electron gun side.The phosphor screen thus obtained has improved brightness as described above, and The contrast is improved, and a smooth fluorescent film with no uneven light emission can be obtained.

[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 an electron gun,
9 is an electron beam.

Next, FIG. 2 is a partial configuration diagram showing details of an example of the configuration of the phosphor 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 continuously in the vertical direction.
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 has a red phosphor fine dot 1
8, a green phosphor fine dot 19, a blue phosphor fine dot 20, and a light absorption film 21 filling the periphery of each of the phosphor fine dots 18 to 20.

The shadow mask 5 is made of a steel plate material, an amber material having a small coefficient of thermal expansion, or the like, and is 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 using a round through hole.

Next, FIGS. 4 and 5 show an embodiment of the phosphor screen according to the present invention and are sectional views 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. The one pixel is coated with the 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.

Further, in FIG. 5, reference numeral 32 is a small-diameter phosphor particle, 33 is a small-diameter phosphor particle layer, and FIG.
The same components as those shown in are denoted by the same reference numerals.
In FIG. 5, the bismuth oxide particle layer 24 shown in FIG. 4 is not formed, and instead, a small-diameter phosphor particle layer 33 is laminated between the face plate 22 and the phosphor particle layer 27. It is configured.

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 stripe pitch 0.75 mm) having a fluorescent screen diagonal dimension of 59 cm, and then, on the face plate 22, Sulfide green phosphor (eg ZnS: Cu, Au, Al) particles having an average particle size of 7 μm has an average particle size of 2 μm.
The slurry obtained by mixing 10 wt% of the rare earth green phosphor (for example, Y ₂ O ₂ S: Tb) particles in a weight ratio is spin-coated, and after the coated slurry is dried, a shadow mask is fitted to perform exposure. After exposure, 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 blue phosphor particles having an average particle size of 8.5 μm are added with an average particle size of 2.5 μm.
The bismuth oxide particles of m were mixed with the blue pigment (cobalt aluminate) at a weight ratio of 0.8 wt% and the bismuth oxide particles were mixed at 10 wt% at a weight ratio, and the slurry was spin-coated, and the applied slurry was used. After the drying, a shadow mask is fitted and exposure is performed. After the exposure, the shadow mask is removed, development is performed with pure water at 40 ° C., and drying is performed to form a blue slurry pattern. Then, to the red phosphor particles having an average particle size of 8.7 μm,
0.8 weight ratio to bismuth oxide particles with an average particle size of 2.8 μm
A slurry obtained by mixing 10 wt% of the bismuth oxide particles coated with wt% red pigment (red iron oxide) in a weight ratio is spin coated, and after the coated slurry is dried, a shadow mask is fitted to perform exposure, and exposure is performed. later,
The shadow mask is removed, development is performed with pure water at 40 ° C., and further drying is performed to form a red slurry pattern.

The green, blue, and red slurry patterns thus obtained each have a specific gravity (3.9 to 4.8) of the phosphor particles 26 when the slurry is dried after spin coating. ), A small-diameter phosphor particle 32 or a bismuth oxide particle 23 having a larger specific gravity (7.2) is first deposited on the face plate 22, and a smaller-diameter phosphor particle layer 33.
Alternatively, the bismuth oxide particle layer 24 is formed, and then the phosphor particles 26 are deposited on the small-diameter phosphor particle layer 33 or the bismuth oxide particle layer 24 to form the phosphor particle layer 27. As a result, As a result, a phosphor screen having the small-diameter phosphor particle layer 33 or the bismuth oxide particle layer 24 on the face plate 22 side and the phosphor particle layer 27 on the electron gun 8 side is obtained.

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 9 emitted from the electron gun 8 is reflected by the bismuth oxide particle layer 24 in the pixel portion having the red and blue slurry patterns. Therefore, the brightness of the phosphor screen is improved and the electron beam 9 is less likely to reach the face plate 22, so that 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. On the other hand, in the pixel portion having a green slurry pattern having a high luminous efficiency, the green phosphor particles 3 made of a rare earth element having a large electron beam scattering property are formed on the small-diameter phosphor particle layer 33.
2 is formed, it is possible to obtain a smooth fluorescent film with uniform emission of light on the phosphor screen due to the electron beam scattering property of the small-diameter phosphor particle layer 33.

Next, FIG. 6 shows another embodiment of the phosphor screen according to the present invention, which is also a cross-sectional view showing the structure of one picture element portion on the phosphor screen.

In FIG. 6, 30 is a small diameter bismuth oxide particle, 31 is a large diameter bismuth oxide particle, 34 is a phosphor particle layer in which the large diameter bismuth oxide particle 31 is mixed,
In addition, 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-diameter bismuth oxide particles 3 coated with pigment particles 25
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 34 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 stripe pitch 0.75 mm) having a fluorescent screen diagonal dimension of 59 cm, and then an average particle diameter of 7 μm.
Sulfide green phosphor (for example, ZnS: Cu, Au, A
l) Particles are mixed with rare earth green phosphor (for example, Y ₂ O ₂ S: Tb) particles having an average particle diameter of 2 μm in a weight ratio of 10 wt% to prepare a slurry, and the slurry obtained here is applied to the inner surface of the panel. Apply by spin coating. Next, the applied slurry is dried, and then a shadow mask is fitted to perform exposure. 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 green striped slurry. Form a pattern. Then, the average particle diameter of 2.3 μm is added to the blue phosphor particles having the average particle diameter of 8.5 μm.
(Small diameter) bismuth oxide particles coated with 0.8% by weight of blue pigment (cobalt aluminate) in weight ratio of 90% by weight, average particle diameter of 8.5 μm (large diameter) in weight ratio Bismuth oxide particles containing 10 wt% are mixed in a weight ratio of 10 wt% to prepare a slurry, 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. Furthermore, red phosphor particles having an average particle size of 8.7 μm and bismuth oxide particles having an average particle size of 2.3 μm (small diameter) coated with 0.8 wt% of red pigment (red iron oxide) by weight ratio are used in the weight ratio. A bismuth oxide particle containing 90 wt% and an average particle size of 8.5 μm (large diameter) in an amount of 10 wt% by weight is mixed to prepare a slurry, and the slurry obtained here is used as the panel. Spin coating on the inner surface. Next, the applied slurry is dried, and then a shadow mask is fitted to perform exposure. 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 red striped slurry. Form a pattern.

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.
The small-diameter phosphor particles 32 or the small-diameter bismuth oxide particles 30 are first deposited on the face plate 22 to form the small-diameter phosphor particle layer 33 or the bismuth oxide particle layer 24, and then the large-diameter bismuth oxide particles. Since the particles 31 and the phosphor particles 26 are deposited on the small-diameter phosphor particle layer 33 or the small-diameter bismuth oxide particle layer 24 to form the phosphor particle layers 27 or 34, the small-diameter fluorescent particles are formed on the face plate 22 side. Body particle layer 33 or bismuth oxide particle layer 2
4. A phosphor screen in which the phosphor particle layer 27 or 34 is arranged on the electron gun 8 side can be 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 the present embodiment, when the color cathode ray tube is used, the electron beam 9 emitted from the electron gun 11 is reflected by the bismuth oxide particle layer 24 in the pixel portion having the red and blue slurry patterns. Therefore, the brightness of the phosphor screen is improved, and the electron beam 9 is less likely to reach the face plate 22, so that the browning level of the face glass is improved. Further, the pigment particles 25 coated on the bismuth oxide particles 30 can improve the contrast of the phosphor screen. Furthermore, in the picture element portion formed of a green slurry pattern having a high luminous efficiency, due to the electron beam scattering property of the small-diameter phosphor particle layer 33, the phosphor screen has a uniform light emission and a smooth fluorescent film having no uneven light emission is formed. Obtainable.

The brightness, contrast, manufacturing cost, and browning of the face glass obtained by each of the above examples are compared with the fluorescent screen of the coating system which is widely used in the past. 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 small-diameter phosphor particles or high-reflection particles with the density of the phosphor particles, it is preferable that the difference is large, but it is possible to obtain sufficient brightness and contrast like a small color cathode ray tube. In such a case, if the highly reflective particles having a density not so different from the density of the phosphor particles are used, the light emission of the phosphor pattern of each color becomes uniform, and the texture of the display screen becomes smooth.

[0049]

As described above, according to the present invention, the fluorescent screen is composed of the highly reflective particle layer formed on the face plate side and the phosphor particle layer formed on the electron gun side. Therefore, the brightness of the phosphor screen can be improved by the reflection of the electron beam by the highly reflective particle layer. Further, by coating the highly reflective particle layer with pigment particles, it is possible to improve the contrast of the phosphor screen. Further, for the phosphor layer having high luminous efficiency, the phosphor layer is composed of a small particle layer having a large specific gravity formed on the face plate side and a large particle layer having a small specific gravity formed on the electron gun side. Thus, it is possible to obtain a smooth fluorescent film in which the light emission from the fluorescent screen is uniform due to the scattering of the electron beam by the small particle layer, and which has no unevenness.

[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 is a cross-sectional view showing an example of a phosphor screen according to the present invention and showing a configuration of another picture element portion on the phosphor screen.

FIG. 6 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. 7 is a cross-sectional view showing one picture element portion of a phosphor screen manufactured by a conventional filter method.

FIG. 8 is a cross-sectional view showing one picture element portion of a phosphor screen manufactured by a conventional coating method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Panel part 2 ... Funnel part 3 ... Neck part 4 ... Phosphor screen 5 ... Shadow mask 6 ... Magnetic shield 7 ... Deflection yoke 8 ... Electron gun 9 ... Electron beam 1 ... Light absorption strip 13 ... Red phosphor strip 14 ... Green phosphor fine strip 15 ... Blue phosphor fine strip 16 ... Slit strip Through hole 17 ... Bridge part 18 ... Red phosphor fine spot 19 ... Green phosphor fine spot 20 ... Blue phosphor fine spot 21 ... Light absorption film 22 ... Face plate of color CRT 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 26 ... Phosphor particles 27 ... Phosphor particle layer 28 ... Aluminum film 29 ... Black matrix 30 ... Small diameter bismuth oxide particles 31 ... Large diameter bismuth oxide particles 32 ... Small diameter phosphor particles 33 Phosphor particle layer mix small diameter of the phosphor particle layer 34 ... bismuth oxide particles having a large diameter.

Claims (2)

[Claims] 1. A cathode ray tube comprising at least a phosphor screen including a phosphor picture element pattern on a face plate on an inner surface of a panel and an electron gun for emitting an electron beam to the phosphor screen, wherein the phosphor screen is an electron gun. A first phosphor having a first phosphor particle layer formed on a side thereof and a high reflection particle layer made of high reflection particles having an average particle size smaller than that of the phosphor particles of the first phosphor particle layer formed on a panel side. A second phosphor particle layer is formed on the pixel pattern and / or the electron gun side, and the second phosphor particle layer is formed on the panel side.
A fluorescent tube having a second phosphor picture element pattern formed by forming a third phosphor particle layer composed of phosphor particles having an average particle size smaller than that of the phosphor particles in the phosphor particle layer. 2. A high-reflectance particle having a density higher than that of the phosphor particles in the slurry and smaller than the average particle diameter of the phosphor particles is mixed in a phosphor slurry of a predetermined color. A phosphor screen is obtained by applying a first slurry and / or a second slurry formed by mixing a plurality of phosphor particles having different average particle sizes to the inner surface of a panel of a cathode ray tube to form a slurry pattern. A method for forming a fluorescent screen of a cathode ray tube, characterized in that