JPH0883574A - Cathode-ray tube - Google Patents

Abstract

PURPOSE: To improve brightness, resolution and the service life of a fluorescent screen by making the unmber of phosphor particle layers 3.0 to 4.0 the fluorescent screen. CONSTITUTION: An electron gun 13 to emit, control, accelerate and focus an electron beam 4 is housed inside a neck 15 to constitute a vacuum envelope, and a fluorescent screen 3 is formed on an inside surface of panel glass 1 so that the layer number of the phosphor particles becomes 3.0 to 4.0. A screen 20 is almost perpendicularly arranged on a front surface, and is magnified by a projecting lens 23 arranged through a coupler 22 reproduced on the fluorescent screen 3 formed on the inside surface of the panel glass of a PPT 21, and it is projected on the screen 20. Here, when the layer number of phosphor particles is larger than 4.0, the entrance of the electron beam does not reach up to a lower layer, and the phosphor particles of an upper layer are diffused or reflected. When the layer number of phosphor particles is less than 3.0, burning of the panel glass 1 is caused, and the service life is reduced.

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 more particularly to a cathode ray tube having a fluorescent film having high brightness and high resolution and long life characteristics.

[0002]

2. Description of the Related Art Generally, a cathode ray tube for displaying a single color or a color is an electron beam on a fluorescent film which emits light of a predetermined color formed by coating on the inner surface of a panel glass which is an image display surface constituting a vacuum envelope. Is irradiated to form an image of a predetermined color.

In recent years, so-called color cathode ray tubes have become the mainstream of cathode ray tubes, and most monitors for consumer equipment such as color television receivers, personal computers, and other information terminal devices employ color cathode ray tubes. There is.

The above-mentioned color cathode ray tube has a phosphor film in which phosphors of three colors are formed in a mosaic shape on the inner surface of the panel glass, and by irradiating each of these phosphor mosaics with an electron beam, a color image is obtained. Is displayed.

A projection type cathode ray tube (PRT) used in a projection type television receiver has three colors (generally red R, green G,
The structure is such that a three-color cathode ray tube having a phosphor film that emits each of blue B) is used, and the emission images of these three cathode ray tubes are optically overlapped to form a full-color image.

In various types of cathode ray tubes as described above, the fluorescent film is formed by applying fluorescent particles having a predetermined color to the inner surface of the panel glass in a plurality of layers, and the fluorescent film is coated with an electron beam emitted from an electron gun. When irradiated, if the layer of the phosphor particles forming the phosphor film is thick, the electron beam does not penetrate to the lower layer, and absorbs light emitted from the phosphor particles in the upper layer or scatters the brightness of the display image. It reduces the resolution.

Particularly, the projection type cathode ray tube is required to have much higher brightness and resolution than the direct-viewing type cathode ray tube, and the deterioration of the brightness and the resolution greatly affects the display image quality.

Regarding the prior art of this kind, the thickness of the fluorescent film and the particle size of the phosphor particles are disclosed in, for example, Japanese Patent Application Laid-Open No. 5-159717, and regarding the projection type cathode ray tube, for example, Japanese Patent Application Laid-Open No. Sho 60. -200216 can be mentioned.

[0009]

As described above, with respect to the brightness and resolution of the cathode ray tube, it is ideal that the fluorescent film formed on the panel glass emits all light. The larger the number of layers, the more the electron beam does not reach the phosphors in the lower layer, resulting in deterioration of the brightness and resolution.

FIG. 8 is a schematic cross-sectional view for explaining the light emission of a fluorescent film in a conventional cathode ray tube, 1 is a panel glass,
2 is a phosphor particle, 3 is a phosphor film, 4 is an electron beam, and 5 is light emission of the phosphor.

For example, when a ZnS type phosphor is used,
Its density is about 4.1, and the acceleration voltage of the electron beam is 30-
When the voltage is 35 kV, the penetration distance of the electron beam 4 into the fluorescent film 3 is 5 to 8 μm.

Conventionally, phosphor particles 2 having an average particle diameter d of 4 to 10 μm or more are used, and the number of layers is set to about 2 to 3 in order to almost satisfy the packing density and obtain the maximum brightness. The film thickness D of the film 3 is 8 to 10 μm.

Therefore, the phosphor particles that emit light are shaded in the figure, and each of the emitted lights is absorbed or scattered by the phosphor particles in the lower layer that does not emit light and the panel glass 1
Exit from. As a result, the brightness and resolution of the display image are reduced.

In order to reduce the film thickness of the fluorescent film, the particle size of the phosphor particles used in the above-mentioned prior art is set to 1/3 to 2/3 of the penetration distance of the electron beam corresponding to the film thickness of the fluorescent film. By doing so, the phosphor particles are almost irradiated with the electron beam.

However, when the particle size of the phosphor particles is made small, the luminous efficiency thereof is deteriorated and the packing density becomes high, so that the acceleration voltage of the electron beam needs to be made high.

The thinner the thickness of the fluorescent film, the less scattering and absorption of light in the fluorescent film and the better the resolution, but the shorter the brightness and the life, the thinner the fluorescent film is. Is limited.

In the prior art, efforts have been made to improve the brightness and resolution of this type of cathode ray tube by means of improving the electron gun and increasing the anode voltage. Therefore, there is a problem that the life of the phosphor is shortened. there were.

An object of the present invention is to solve the above-mentioned problems of the prior art and to maintain a required film thickness, high brightness and high resolution,
Another object of the present invention is to provide a cathode ray tube having a long-life fluorescent film.

[0019]

In order to achieve the above object, the first invention according to claim 1 is such that the phosphor particles are formed on the inner surface of the panel glass 1 as shown in the schematic sectional view of FIG. Two
In a cathode ray tube having a fluorescent film 3 formed by forming a plurality of layers, the number of the phosphor particle layers constituting the fluorescent film is set in the range of 3.0 to 4.0. .

A second aspect of the present invention is a projection type cathode ray tube having a fluorescent film formed by forming a plurality of green fluorescent substance particle layers on the inner surface of a panel glass. The number of phosphor particle layers constituting the above is 3.0 to 4.
It is characterized in that it is within the range of 0.

Further, a third invention according to claim 3 is
The phosphor film according to the first or second invention is a pigmented Y ₃ (Al, Ga) ₅ O ₁₂ ; Tb [P53 (G
a)] and Zn ₂ SiO ₄ ; Mn [P1] in a weight ratio of 93:
It is characterized in that it is composed of phosphor particles mixed in 7.

[0022]

When the number of layers of the phosphor particles forming the phosphor film formed on the panel glass is large, the penetration of the electron beam does not reach the lower layer, and the phosphor particles in the upper layer emit light in various layers. The light is scattered, reflected, or absorbed by the light, resulting in a decrease in brightness.

Further, when the number of layers of the phosphor particles is large, the phosphor material is deteriorated to lower the brightness, and when the number of layers of the phosphor particles is small, the panel glass is burnt (browning) and the life is shortened. To do.

FIG. 2 is an explanatory view of the relationship between the thickness of the PRT fluorescent film having a green fluorescent film and the brightness characteristics.

In the figure, Y ₃ (Al, Ga) with pigment is added.
₅ O ₁₂ ; Tb [P53 (Ga)] and Zn ₂ SiO ₄ ; M
The relative brightness was evaluated by using four types of fluorescent film thicknesses in which the particle size of the phosphor particles obtained by mixing n [P1] at a weight ratio of 93: 7 was 5 μm, 7 μm, 9 μm, and 11 μm.

In the above evaluation, a 7-inch PRT in which the fluorescent film was formed at a high density by a centrifugal sedimentation method was used, and the anode voltage (Eb): 28 kV and the cathode current (Ik): 350 μ.
A, luminance measurement area: Measured at 110 × 90 mm ² .

As is clear from this evaluation result, the film thickness of the fluorescent film is approximately 17.5 μm, 24.5 μm, and 3 respectively.
Good luminance characteristics are shown at 1.5 μm and 38.5 μm, that is, in the range of 3 to 4 layers having a peak at about 3.5 layers.

FIG. 3 is an explanatory diagram of the relationship between the number of layers of phosphor particles forming the PRT phosphor film having a green phosphor film and the luminance maintenance ratio.

In the figure, similar to the evaluation of the brightness characteristics,
Pigmented Y ₃ (Al, Ga) ₅ O ₁₂ ; Tb [P53
(Ga)] and Zn ₂ SiO ₄ ; Mn [P1] in a weight ratio of 9
The particle size of the phosphor particles mixed at 3: 7 is 5 μm, 7 μm,
Regarding the number of layers of four types of fluorescent films of 9 μm and 11 μm, 200
This is an evaluation of the luminance retention rate after 0 hour running.

Similarly, in the above evaluation, a 7 type PRT in which the fluorescent film was formed at a high density by the centrifugal sedimentation method was used, and the anode voltage (Eb): 28 kV and the cathode current (Ik): 35.
The measurement was performed at 0 μA and a luminance measurement area of 110 × 90 mm ² .

From the results of this evaluation, the number of layers in the phosphor film using the phosphors having all the above-mentioned particle diameters is 3.0 to
Good characteristics are exhibited within the range of 4.0, and especially the number of layers is 3.5.
It can be seen that the best brightness is shown in the vicinity.

Burning of the panel glass due to the electron beam penetrating the fluorescent film becomes remarkable when the number of layers is 3.0 or less, and when the number of layers is 4.0 or more, heat dissipation in the fluorescent film is reduced to promote deterioration of the phosphor. I will let you.

From the above, regardless of the particle size of the phosphor particles, both the relative brightness and the brightness retention rate are favorable when the number of layers is within the range of 3.0 to 4.0, particularly around 3.5. It is clear that the brightness, resolution and lifetime of the phosphor screen can be obtained.

That is, according to each of the above-described configurations of the present invention, the brightness and resolution are improved, the life of the phosphor is extended, and high-quality image display can be ensured for a long period of time.

Although the above description has been made on the green fluorescent film, the present invention can be similarly applied to the fluorescent films of other colors, and is not limited to the projection type cathode ray tube but of other types. It goes without saying that it can also be applied to a cathode ray tube.

[0036]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 4 is a partial sectional view for explaining the structure of a projection type cathode ray tube which is one embodiment of the cathode ray tube according to the present invention, in which 1 is a panel glass, 3 is a fluorescent film, 4 is an electron beam. 6 is a funnel, 7 is a deflection yoke, 8 is a convergence yoke, 9 is a centering magnet, 10 is a focus magnet, 11 is an electromagnetic lens, 12 is a beam alignment magnet, 13 is an electron gun, 14 is an electrostatic auxiliary lens, and 15 is a neck. Is.

This projection type cathode ray tube (PRT) is a composite focusing type in which an electromagnetic lens and an electrostatic lens are used in combination. The upper side is a half sectional view of the main part and the lower side is a half side view of the main part.

In FIG. 1, an electron gun 13 for radiating, controlling, accelerating and focusing the electron beam 4 is housed inside a neck 15 which constitutes a vacuum envelope, and the inner surface of the panel glass 1 is, for example, green. Is formed so that the number of layers of the phosphor particles is 3.5.

A deflection yoke 7 for horizontally and vertically deflecting the electron beam 4 is attached around the funnel 6. Further, the free spot positions of the convergence yoke 8 and the electron beam 4 for adjusting the misconvergence (color misregistration) with the image reproduced by another PRT are successively adjusted adjacent to the side of the neck 15 of the deflection yoke 7. A centering magnet 9 and a focus magnet 10 forming an electromagnetic lens 11 for focusing the electron beam 4 are attached.

Further, a beam alignment magnet for aligning the central axis of the electromagnetic lens 11 formed by the focus magnet 10 with the passage axis of the electron beam 4 is provided on the outer periphery of the neck 15 in which the electron gun 13 is housed. 12 is attached.

FIG. 5 is an enlarged view of the main part of the panel glass portion of the projection type cathode ray tube shown in FIG. 4, in which 16 is a frit seal for joining the panel glass and the funnel, and 17 is a high voltage supplied to the fluorescent screen. For the anode cap, 18 is a contact spring, 19 is a tension band, and FIG.
The same reference numerals as in FIG. Reference numeral 31 denotes a multilayer interference film for effectively emitting the light from the fluorescent film 3, and only the light from the fluorescent film 3 that is emitted substantially perpendicular to the panel glass 1 is transmitted to allow the front surface of the panel glass to pass. The light output taken in by the projection lens disposed at is increased. Further, 32 is a metal back, which electrically connects the anode cap 17 and the metal back 32.

The fluorescent film 3 shown in the figure is formed by the number of layers according to the present invention described above, and by this fluorescent film structure, a fluorescent film having long brightness, resolution and long life is formed to form a high quality image. .

FIG. 6 is an external view of a projection type color television receiver using a cathode ray tube according to this embodiment, and FIG. 7 is a schematic sectional view for explaining the internal structure of FIG. 6, where 20 is a screen and 21 is a screen. PRT, 22 is a coupler, 23 is a projection lens, and 24 is a mirror.

In each of the figures, the screen 20 is arranged substantially vertically on the front surface, and a projection lens in which an image reproduced on a fluorescent film formed on the inner surface of the panel glass of the PRT 21 is installed via a coupler 22. It is enlarged by 23 and projected on the screen 20 by the mirror 24.

The PRT 21 is provided with three units in charge of image signals of three colors (R, G, B), and the images of the respective colors from the three PRTs 21 are superimposed on the screen 20 to form a color image. Reproduce. The fluorescent film of PRT21 is formed by the number of layers described above.

According to the above-described embodiment, it is possible to provide a projection type color television receiver capable of ensuring high-quality image display in which the brightness and resolution are improved and the life of the phosphor is long, for a long period of time.

[0048]

As described above, according to the present invention,
Regardless of the particle size of the phosphor particles, in both the relative brightness and the brightness maintenance ratio, the brightness and resolution of the phosphor film are good when the number of layers is within the range of 3.0 to 4.0, particularly around 3.5. It is possible to provide a cathode ray tube having a long life and a long life of the phosphor, and it is possible to secure high-quality image display for a long period of time.

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating a structure of a fluorescent film of a cathode ray tube according to the present invention.

FIG. 2 is an explanatory diagram of a relationship between a thickness of a PRT fluorescent film having a green fluorescent film and a luminance characteristic.

FIG. 3 is an explanatory diagram of a relationship between the number of layers of phosphor particles forming a PRT fluorescent film having a green fluorescent film and the luminance retention rate.

FIG. 4 is a partial cross-sectional view for explaining the structure of a projection type cathode ray tube which is one example of the cathode ray tube according to the present invention.

5 is an enlarged view of a main part of a panel glass portion of the projection type cathode ray tube shown in FIG.

FIG. 6 is an external view of a projection type color television receiver using a cathode ray tube according to the present embodiment.

7 is a schematic cross-sectional view illustrating the internal structure of FIG.

FIG. 8 is a schematic sectional view illustrating light emission of a fluorescent film in a conventional cathode ray tube.

[Explanation of symbols]

 1 Panel Glass 2 Phosphor Particles 3 Fluorescent Film 31 Multilayer Interference Film 32 Metal Back 4 Electron Beam 5 Emitted Light 6 Funnel 7 Deflection Yoke 8 Convergence Yoke 9 Centering Magnet 10 Focus Magnet 11 Electromagnetic Lens 12 Beam Alignment Magnet 13 Electron Gun 14 Electrostatic Auxiliary lens 15 Neck 16 Frit seal 17 Anode cap 18 Contact spring 19 Tension band.

Claims (3)

[Claims] 1. A cathode ray tube having a fluorescent film formed by forming a plurality of fluorescent substance particle layers on the inner surface of a panel glass, wherein the number of fluorescent substance particle layers constituting the fluorescent film is 3.0 to 3.0.
A cathode ray tube characterized in that it is within a range of 4.0. 2. A projection type cathode ray tube having a fluorescent film formed by forming a plurality of green fluorescent substance particle layers on the inner surface of a panel glass, wherein the number of fluorescent substance particle layers constituting the fluorescent film is 3 .0 to
A cathode ray tube characterized in that it is within a range of 4.0. 3. The phosphor film according to claim 1, wherein the phosphor film is pigmented Y ₃ (Al, Ga) ₅ O ₁₂ ; Tb [P53.
(Ga)] and Zn ₂ SiO ₄ ; Mn [P1] in a weight ratio of 9
A cathode ray tube comprising phosphor particles mixed at 3: 7.