JPH05299018A - Cathode ray tube - Google Patents

Abstract

PURPOSE:To provide a uniform film thickness while preventing coating unevenness and sticking of foreign matters and to form a smooth coated film by forming the coated film on the outer surface of a cathode-ray tube panel part in a closed state. CONSTITUTION:A cathode-ray tube 14 is fixed with a reinforcing metal fittings 21, and covered with an enclosed container 17 so as to rotate the cathode-ray tube 14 in the arrow mark 22 direction. At the same time, a solution 19 for coated film formation is infected from a supply nozzle 18 to the outer surface 15 of a panel part 1, and by maintaining the rotation for shaking off the solution for a fixed time, the solution 19 is spread over the surface 15 and dried to form a smooth coated film. After that, firing is performed at a fixed temperature for a prescribed time so as to make it a rigid coated film. Since by covering the tube with the container 17, the surface to be coated is overall filled with vapor of a coat-forming material with no influence of a peripheral environment, the coating and drying are uniformly performed, and at the same time sticking of foreign matters can be prevented, and a coated film having a uniform film thickness can be formed without unevenness of coating.

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 in which a film having various functions such as antireflection, antistatic and light selective absorption is formed on the outer surface of a panel portion (face surface) which is an image screen of a cathode ray tube. Regarding tubes.

[0002]

2. Description of the Related Art A cathode ray tube used for displaying a color image (hereinafter referred to as a color cathode ray tube) comprises a panel portion which is an image screen, a neck portion for accommodating an electron gun, and a funnel portion for connecting the panel portion and the neck portion. A deflection device for scanning an electron beam emitted from an electron gun on a phosphor screen coated and formed on the inner surface of the panel is attached to the funnel portion.

The electron gun housed in the neck portion is provided with various electrodes such as a cathode electrode, a control electrode, a focusing electrode and an accelerating electrode, and an electron beam from the cathode electrode is modulated by a signal applied to the control electrode. A desired cross-sectional shape and energy are applied through the focusing electrode and the accelerating electrode so that the fluorescent surface is bombarded. On the way from the electron gun to the fluorescent screen, the electron beam is deflected in the horizontal direction and the vertical direction by the deflecting device provided in the funnel portion, and is deflected in the horizontal and vertical directions by the deflecting device provided in the funnel portion. It forms an image (Japanese Patent Laid-Open No. 59-215640).

Since the outer surface of the panel portion of the cathode ray tube is generally formed in a glossy state, incident external light is strongly reflected by the outer surface, making it difficult to see an image displayed on the outer surface. Further, since the outer surface has a high surface resistance, there is a problem that the display surface is charged with static electricity during operation. Further, as one method for improving the contrast of an image, a face plate colored so as to have specific optical characteristics is used. However, it is not possible to obtain various kinds of optical characteristics by coloring the face plate itself. It is not easy and it is not good in terms of manufacturing cost.

In order to prevent such inconvenience, the present inventors have developed an antireflection film on the outer surface of the panel portion of the cathode ray tube (JP-A-62-136740, JP-A-63-193101).
(See Japanese Patent Laid-Open Publication No. Heisei) and an antistatic film (JP-A-1-186533)
No. 2, JP-A-2-68841), or a coating having a light selective absorption and an antistatic function (JP-A-3-1).
1532). These coatings are formed by spin coating, dip coating, or spray coating of an alcohol solution of Si (OR) ₄ (R is an alkyl group) containing an antireflection material, a conductive material, or a photoselective absorbing material. The above various functions can be obtained by applying one to several layers on the outer surface of the panel portion of the tube and baking. Generally, a coating having fine irregularities is obtained by a spray coating method, and a smooth coating is formed by a spin coating method or a dip coating method.

[0006]

Among the above proposals, in particular, a smooth coating formed by a spin coating method or a dip coating method has a uniform film thickness over the entire outer surface of the panel portion of the cathode ray tube, and However, it was not easy to form with good mass productivity without problems such as coating unevenness and adhesion of foreign matter, and without lowering the manufacturing yield. Further, it is very difficult when the surface to be coated has a large area such as a large-sized cathode ray tube, or when several coats are formed to obtain a desired function.

That is, when a smooth coating film is formed by the spin coating method, a coating solution (alcohol of Si (OR) ₄ (R is an alkyl group) containing an antireflection material, a conductive material, or a photoselective absorbing material) Solution) on the entire surface to be coated (the outer surface of the panel part of the cathode ray tube), and then the excess solution is shaken off by applying high speed rotation of 100 to 200 rpm to make the solution uniform. Moves to the periphery due to centrifugal force, and the solution is dried by the wind caused by rotation before it scatters, causing ring-shaped unevenness. The influence of wind caused by this rotation is overwhelmingly stronger in the corner portion than in the central portion of the surface to be coated, and there is a problem in that strong coating unevenness occurs particularly in the corner portion. Therefore, the film thickness of the obtained coating is not uniform, and only a nonuniform film having a thin central portion and a thick corner portion can be obtained. Therefore, when a plurality of coatings are formed to obtain an antireflection function, the predetermined characteristics cannot be obtained unless the film thickness of each coating is uniformly controlled, which adversely affects the reflection characteristics. Further, since the surface to be coated is open, it is easy to pick up foreign matter wound up due to sedimentation or rotation on the surface to be coated, and there is a problem if it is dried with the foreign matter attached.

When a smooth film is formed by the dip coating method, the surface to be coated is dipped in a solution for forming a film, and then the solution is dried while the surface to be coated is pulled up as it is, or the surface to be coated is made vertical. Although the solution is dried by standing in the vertical direction, but when the surface to be coated is pulled up as it is, the drying of the solution starts from the pulled up portion, so contrary to the spin coating method, the film thickness in the peripheral part is thin and the central part is It becomes thick. Further, when the solution is dried by erecting the surface to be coated, the solution applied at the time of drying is lowered downward, so that the film thickness of the lower portion at the time of drying is inevitably increased. Also,
If the drying speed is not uniform on the surface to be coated, striped coating unevenness occurs. In the case of this dip coating method as well as the spin coating method, there is a problem if the surface to be coated is dried with foreign matter attached.

The object of the present invention is to solve the above-mentioned problems,
An object of the present invention is to provide a cathode ray tube capable of efficiently forming a coating film having a predetermined function with good yield on the outer surface of the panel portion.

[0010]

In order to achieve the above object, the present invention provides a cathode ray tube in which at least one layer of coating having a predetermined function is formed on the outer surface of a panel portion.
The outer surface is sealed, and the coating solution is applied to the outer surface to provide a cathode ray tube having the coating formed thereon.

[0011]

According to the present invention, the outer surface of the panel portion of the cathode ray tube is hermetically sealed and the coating solution is applied by the spin coating method or the dip coating method, so that it is affected by the wind by the rotation and the surrounding environment. Since the entire surface to be coated is filled with the vapor of the film forming material, coating and drying are performed uniformly,
In addition, since the probability of adhesion of foreign matter is much smaller in the closed state than in the open state, it is possible to form a coating film having a uniform film thickness on the entire surface to be coated and free from coating unevenness and foreign matter attachment.

[0012]

EXAMPLES The cathode ray tube of the present invention will be specifically described below with reference to examples.

FIG. 3 is a schematic constitutional view showing an embodiment of the present invention, in which 14 is a cathode ray tube, 1 is a panel portion, 15 is an outer surface of the panel portion 1, and 16 is an outer surface 15 of the panel portion 1. A film formed of a single-layer or multi-layer thin film containing, for example, SnO ₂ , In ₂ O _3, etc. having various functions such as antireflection, antistatic, and selective absorption of light, 2 is a funnel, 3 is a neck portion,
4 is a fluorescent screen (screen), 5 is a shadow mask, 6 is a magnetic shield, 7 is a deflection yoke, 8 is a purity adjusting magnet, 9 is a center beam static convergence adjusting magnet, 10 is a side beam static convergence adjusting magnet, and 11 is an electron. A gun, Bc is a center beam, and Bs is a side beam.

In the convergence adjustment (static convergence) of such a 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.

Although not shown, an inner conductive film made of graphite or the like is deposited on the inner surfaces of the funnel 2 and the neck 3, and the conductive film contains not only graphite but also titanium dioxide or the like for the purpose of suppressing arcing. It controls the resistance value. The conductive film electrically connects a high voltage terminal (not shown) to the electron gun 11.

Hereinafter, the panel portion 1 of the cathode ray tube 14 of the present invention.
The coating film 16 formed on the outer surface 15 will be described.

FIG. 1 is a partial cross sectional view showing an apparatus for forming a coating film 16 on the outer surface 15 of the panel portion 1 of the cathode ray tube 14 by the spin coating method. In the figure, 17 is a hermetic container for hermetically sealing the outer surface 15 of the panel part 1 of the cathode ray tube 14, and 18 is provided so as to penetrate the hermetic container 17 so that the film-forming solution is applied to the outside of the panel part 1 of the cathode ray tube 14. A supply nozzle for supplying to the surface 15, 19 for a film forming solution supplied from the supply nozzle 18, and 20 for discharging the film forming solution applied to the outer surface 15 of the panel portion 1 of the cathode ray tube 14. It is an outlet. The shape of the closed container 17 viewed from above is, for example, a circular shape, and the discharge port 20 is provided over the entire circumference of the circular shape and is connected to the waste liquid pipe. Reference numeral 21 is a reinforcing metal member provided on the cathode ray tube 14, and 22 is an arrow indicating the rotation direction in which the cathode ray tube 14 is rotated by a spin coater (not shown).

The coating solution is, for example,
Antireflection SiO ₂ , Antistatic SnO ₂ , In ₂ O ₃
Si (OR) ₄ containing fine particles (OR is an alkyl group)
Alcohol solution was used.

Next, a method for forming the coating film 16 having a predetermined function on the outer surface 15 of the panel portion 1 of the cathode ray tube 14 by the spin coating method using the apparatus shown in FIG. 1 will be described.

First, the outer surface 15 of the panel portion 1 of the cathode ray tube 14 is cleaned with an alkaline cleaner. Next, the cathode ray tube 14 is fixed to a spin coater (not shown) by using, for example, the reinforcing metal fitting 21 of the cathode ray tube 14, and the hermetically sealed container 17 is covered on the outer surface 15 of the panel portion 1 of the cathode ray tube 14 to form the hermetically sealed container 17 After being fixed by an appropriate means, for example, 100r
The cathode ray tube 14 is rotated at a speed of pm as shown by an arrow 22, and at the same time, the film forming solution 19 is supplied to the nozzle 1.
8 onto the outer surface 15 of the panel portion 1 of the cathode ray tube 14. The coating film was shaken off at a constant speed for a certain period of time, or at the same time when the film-forming solution spreads over the entire surface to be coated (outer surface 15), the coating film was dried by further shaking at a higher speed to form a smooth film. Further, in the case of forming several coats, the coat of the first layer was completely dried and then the coating liquid of the second layer was supplied and coated in the same manner to form a multilayer film. Then, this coating film was baked at a constant temperature for a predetermined time to form a strong film.

FIG. 2 is a partial cross sectional view showing an apparatus for forming a coating film by the dip coating method. In the figure, 23 is a solution tank for filling the film forming solution 19, 24 is a closed container for sealing the outer surface 15 of the panel portion 1 of the cathode ray tube 14, and 25 is provided so as to penetrate the closed container 24, A supply nozzle for supplying the film forming solution 19 to the solution tank 23, and a discharge pipe 26 for discharging the film forming solution 19 which overflows at a predetermined level.

In order to form a coating film by the dip coating method using the apparatus shown in FIG. 2, the outer surface 15 of the panel portion 1 of the cathode ray tube 14 which has been cleaned with an alkaline cleaner is sealed as in the spin coating method. After being immersed in the film forming solution 19 in the solution tank 23 installed in the container 24, the film was pulled up at a constant speed, applied and dried to form a smooth film on the outer surface 15. Further, when forming a multilayer film, as in the case of the spin coating method, the second layer was formed after the first layer solution was dried. Then, it was baked at a constant temperature for a predetermined time to form a strong coating. In addition, in the present embodiment, the case where the surface to be coated is immersed is described, but it goes without saying that the surface to be coated may be vertically erected, immersed, and then coated and dried.

The coating film formed by using the apparatus shown in FIGS. 1 and 2 is a uniform film over the entire surface and has no defects such as coating unevenness and adhesion of foreign matter, and has excellent antireflection, antistatic or light selective absorption functions. I had. That is, in each of the above embodiments, the outer surface 15 of the panel portion 1 of the cathode ray tube 14 is sealed with the closed container 17 or 24 and the coating solution is applied by the spin coating method or the dip coating method. Because the vapor of the film-forming material fills the entire surface to be coated without being affected by wind or the surrounding environment due to
Since the drying is performed uniformly and the probability that foreign matter adheres is overwhelmingly smaller in the closed state than in the open state, the film thickness on the entire surface to be coated is uniform, and there is no uneven coating or foreign matter adhesion. A film having a function can be formed. Moreover,
The above method is excellent in mass productivity.

FIG. 4 shows an example of the electron gun 11, and G3 and G4 constituting a bipotential type main lens.
FIG. 3 is a cross-sectional view of electrodes in a horizontal direction and a vertical direction. In the figure, 111 is the outer peripheral portion of the G3 electrode, 121 is the outer peripheral portion of the G4 electrode, and 13 is the cup electrode. Reference numeral 112 denotes an astigmatism correction electrode provided inside the outer peripheral portion 111 of the G3 electrode, and 122 denotes an astigmatism correction electrode provided inside the outer peripheral portion 121 of the G4 electrode. The electrode plate 112 has a hole 114 through which the central beam passes, the holes 113 and 113 'through which the outer beam passes, and the electrode plate 122 has a hole 124 through which the central beam passes and a hole through which the outer beam passes. 12
3, 123 'are provided in a line. In this example,
Openings 113, 113 ', 114, 123, 123'12
Reference numeral 4 is an ellipse, and the shapes and dimensions of the corresponding openings on the G3 side and the G4 side are the same. Outer hole 11
3, 113 ', 123, 123' and the central aperture 114,
If the shape and size of 124 are the same, the lens focusing action in the horizontal direction of the main lens formed on the outside becomes stronger, so the horizontal diameter of the outer opening is made larger than the inner diameter of the central opening in the horizontal direction. Equalize the strength of focusing action in both horizontal and vertical directions.

FIG. 5 shows that, in the embodiment shown in FIG. 4, the outer peripheral portions 111 and 121 have a horizontal diameter h = 20.0 mm, a vertical diameter v = 9.4 mm, and the central holes 114 and 124 in the vertical direction. Diameter a ₁ = 8.4 mm, retreat amount of electrode plate 112 d ₁ = 1.5
mm, eccentricity S = 6.6 mm, central aperture 11
The ratios of the focus distances in both the horizontal and vertical directions to the horizontal direction diameter b ₁ of 4, 124 are obtained by computer simulation.

The term "horizontal or vertical focus distance" as used herein means that an electron beam emitted from one point on the central axis at a certain emission angle and passing through the horizontal or vertical symmetry axis of the central aperture is focused by the main lens. The distance until it crosses the central axis again is measured from the end surface of the G3 electrode on the G4 electrode side. The distance from the end face to the fluorescent screen is set to 340 mm, the emission points at which the emission angles match this value of 340 mm are obtained, respectively, and the electron beam is emitted at the same emission angle from the intermediate point between these emission points. .. FIG. 5 shows the ratio of the focus distances in both the horizontal and vertical directions at this time. As can be seen from the figure, if the horizontal diameter of the central aperture is b ₁ ≈5.5 mm, the vertical and horizontal focus distances will match, and the focusing strength in both directions will be equal, so astigmatism will be reduced. Can be removed.

The lens focusing action at this time is 1 mm.
It has the same strength as a cylindrical bi-potential lens with a diameter of 8 mm, which is abutted at an interval of.

When h = 20.0 mm and S = 6.6 mm, this is L = h−2 × S (L = limit value of aperture diameter, h =
The value is larger than the limit value of 6.8 mm for the electrode opening portion, which is restricted by the horizontal diameter of the opening, S = eccentric distance of the opening portion.

FIG. 6 shows the outer openings 113 and 11 in the embodiment shown in FIG.
The relationship between the value of the horizontal direction diameter b ₁ of 3 ', 123, 123' and the horizontal spot movement distance of the outer electron beam on the fluorescent screen is obtained by computer simulation. 7 kV was applied to the G3 electrode and 25 kV was applied to the G4 electrode, and the distance from the end of the G3 electrode on the G4 electrode side to the phosphor screen was 340 mm. Since the outer electron beam and the central electron are separated by 6.6 mm in the horizontal direction, the spot movement distance required to obtain the STC is 6.6 mm. In order to leave the gap, it is often designed to be about 6.1 mm. To secure this movement distance,
The value of b ₁ is 5.8 mm.

FIG. 7 is a cross-sectional view of an essential part of another embodiment of the electron gun of the cathode ray tube of the present invention, showing a vertical cross section of the G3 electrode. Openings 41, 4 provided in the electrode 112
1'and 42 have a shape in which the end points of two arcs are connected by two parallel straight lines. Although the spot shape on the fluorescent screen is worse than that of an elliptical opening, it has an advantage that it can be easily and accurately machined because the opening is composed of an arc and a straight line. Also in this embodiment, the horizontal diameter of the opening is smaller than the vertical diameter.

FIGS. 8 and 9 are sectional views showing the essential parts of still another embodiment of the electron gun of the present invention. The G3 electrode and the G4 electrode, respectively.
It is a figure which shows the vertical cross section of an electrode. Central aperture 5
2, 62 have an axis of symmetry in the vertical direction but the outer openings 51,
51 ', 52, 52' do not have a vertical symmetry axis.
The outer holes 51, 51 ', 52, 52' have the same major axis,
It is a combination of two ellipses with different minor axes.
The outer openings 51, 51 'of the three electrodes are smaller than the minor axis of the ellipse combined to the outside. When the outer aperture of the G3 electrode is formed in such a shape, the force for concentrating toward the center of the electron beam becomes stronger than in the case where the aperture is one ellipse like 113 and 113 'in FIG. Even if the diameter in the direction is made smaller, the STC can be obtained.

On the contrary, in the G4 electrode, 61, 61 'in FIG.
As described above, if the outer opening is formed by combining two ellipses whose minor axis of the inner ellipse is smaller than that of the outer ellipse,
The force to concentrate the electron beam toward the center becomes stronger.

As described above, if the outer openings are made asymmetric with respect to the vertical direction, the concentration force on the electron beam increases, and S
It becomes easy to take TC. Also, if your concentration is too strong,
If the aperture of FIG. 8 is used on the G4 electrode side and the aperture of FIG. 9 is used on the G3 electrode side, the concentration can be weakened.

According to the present invention, a cylindrical electrode having the maximum diameter that is possible when the main lenses corresponding to the three colors of red, green and blue are arranged in parallel on the same horizontal plane while the outer shape of the electron gun is restricted is provided. Since the main lens having a weaker focusing effect than that in the case of abutting can be configured, there is an effect that the focusing characteristics of the cathode ray tube can be remarkably improved.

Further, the G3 electrode and the G which constitute the main lens
Since the STC can be obtained by appropriately selecting the retreat amount of the electrode plate and the shape of the hole formed in the electrode plate without deviating the central axis of the outer hole formed in the four electrodes. At the time of assembly, jigs having the same diameter and the same axis can be used for the G3 electrode and the G4 electrode, and the assembling accuracy can be improved.

FIG. 10 is a partially cutaway perspective view showing an essential part of another embodiment of the electron gun of the present invention. The electrode plates 133 and 143 are
For the central beam, an elliptical aperture 1 similar to the polar plate of FIG.
35 and 145 respectively, the elliptical aperture is cut in half for the side beams on both sides, and the portions in contact with the outer peripheral electrodes 131, 141 at both left and right ends are removed.
The passage of the central beam is surrounded by the holes 135 and 145 formed in the plates 133 and 143, respectively, while the passages of the side beams on both sides are formed by the plates 133 and 143.
Are partially surrounded by the end portions of, and the remaining portions are surrounded by the outer peripheral electrodes 131 and 141. With such a configuration, the diameter of the main lens for the side beam can be maximized, and since the area of the electrode plate is small, it is easy to increase the flatness and the elliptical aperture that requires high accuracy. There is an advantage that processing is easy because there are few molded parts. d ₃ and d ₄ indicate the amount of retreat, and either the same or different values are adopted.

In the embodiment of FIG. 10, the shape of the aperture is an ellipse, but if the diameter of the aperture in the vertical direction is larger than the diameter in the horizontal direction, astigmatism can be removed by using other shapes.

Further, as shown in FIG. 11, the electrode plates 133,
Astigmatism can also be eliminated by a structure in which 143 is curved and the retreat amount of the polar plate is continuously changed. At this time, the vertical diameters of the openings 135 and 145 are not necessarily larger than the horizontal diameter. When the electrode plate 133 of the G3 electrode is convex toward the G4 electrode side as shown in the drawing, the horizontal focusing force can be strengthened, and conversely, when the electrode plate of the G4 electrode is convex toward the G3 electrode side, vertical focusing is possible. You can strengthen your strength.

Further, as shown in FIG.
It is also possible to correct the astigmatism by providing protrusions 137 and 147 around 5, 145 and adjusting the protrusion amount of the protrusions. In this case as well, the vertical diameter of the opening need not be larger than the horizontal diameter.

11 and 12, it is possible to correct astigmatism while leaving the apertures as perfect circles. In this case, in the case of non-circular apertures, both parts machining and electrode assembly are performed. It has the advantage of being easier than.

According to this embodiment, the halo generated in the inner direction of the side beam can be removed, the effective aperture diameter of the electron gun main lens can be sufficiently enlarged, and the focus characteristic of the color picture tube is remarkably improved. There is an effect that can be done. Further, since the areas of the electrode plates of the main lens facing each other are small, it is easy to obtain flatness during processing, and further, there are advantages that molding is easy because there are relatively few processing points.

Of course, the electron gun of the present invention can be applied to the main lens of the above-mentioned bipotential type or any other type. Further, in the above description, the example in which the present invention is applied to both of the pair of electrodes forming the main lens has been described, but the same effect can be obtained by applying the present invention to only one of the electrodes.

FIG. 13 shows a front view (a), a side view (b), a rear view (c) and a plan view (d) of an electron gun of another embodiment having first to sixth grids. In the figure, 1111 is the first grid, 1112 is the second grid, 1113 is the third grid.
A grid, 1114 is a fourth grid, 1115 is a fifth grid, 1116 is a sixth grid, and 1119 is a cathode. This electron gun uses a plurality of main lenses to obtain good focus characteristics. In order to obtain a bright and high-resolution image, it is necessary to increase the value of the anode voltage Eb, and usually Eb is 25 to 35 kV. The focus voltage Ec ₃ is about 30% of Eb, the applied voltage Ec ₂ of the second grid 1112 is about 400 to 700V, the first grid 1111 is grounded, and the cathode 1119 has a voltage of 200V or less corresponding to the brightness of each pixel. The voltage Ek for the signal is applied. Further, 1127 is a third grid power supply line, 1128 is a fifth grid power supply line, and the third grid power supply line 1127 is shown in FIG.
As shown in (b) and (c), one end 1127a is fixed to the third grid 1113, and a part of the intermediate portion 1127b extends substantially parallel to a plane orthogonal to the tube axis.
7c, and the bent portion 1127c is the third grid 111.
3, the intermediate portion between the back surface of the bead glass 1120 and the inner wall surface of the neck tube (not shown) is passed within the overall length 1 in the tube axis direction, and the other end 1127d is connected to a stem lead (not shown). This causes the same operation as the shield wire. Meanwhile, the third grid 11113 and the fifth grid 111
The fifth grid feeder line 1128 for connecting to FIG.
As shown in (a) and (b), one end 1128a is the third grid 1113 and the other end 1128d is the fifth grid 1113.
A bent portion 1128 which is fixed to each of 15 and extends a part of the intermediate portion 1128 substantially parallel to a plane orthogonal to the tube axis.
c, the bent portion 128c is symmetrically arranged within the overall length 1 of the third grid 1113 in the tube axis direction and on the same plane orthogonal to the tube axis with the bent portion 1127c and the tube axis interposed therebetween. The glass 120 is passed through an intermediate portion between the back surface of the glass 120 and the inner wall surface (not shown) of the neck tube, and the same action as the shield wire is performed. That is, power supply lines 1127C, 1128C
Since they are placed symmetrically in the same plane that is sandwiched by the tube axis and orthogonal to the tube axis, arc discharge suppression effect, etc. can be achieved over the entire circumference in the neck tube as compared with the case where the shield wire is placed on only one side. It has the excellent feature of exhibiting.

Further, as in the present embodiment, both bent portions 1127c and 1128c are symmetrically arranged within the entire length of the third grid in the tube axis direction and sandwiching the tube axis, whereby the number of arc discharge occurrences can be reduced. Compared with the conventional one, it can be reduced to a fraction or less, and the dark current value can be similarly reduced to a fraction or less. That is, in terms of shielding the bead glass and the neck tube wall from the anode voltage, it is better to provide a bent portion near the electrode to which the anode voltage is applied. It is also possible that arc discharge easily occurs. On the other hand, if the bent portion of the focus voltage applying power supply line is too close to the second grid electrode side, the focus voltage is a high voltage, which is as high as the anode voltage. Therefore, the bent portion of the focus voltage applying power supply line and the second grid electrode, etc. The risk of generating arc discharge with the low-voltage applying electrode becomes large.

Regarding the position of the bent portion of the focus voltage applying power supply line, the bent portion was examined based on various experiments based on various effects such as arc discharge suppressing effect, dark current suppressing effect, and electrode assembly workability. Is optimally provided at a position facing the side surface within the overall length 1 of the third grid in the tube axis direction.

According to this embodiment, since both ends of the power supply line are fixed to the electrodes and the like, there is no fear of becoming a source of stray electrons, and there are effects of preventing arc discharge and suppressing dark current.

Next, FIG. 14 shows details of an example of the fluorescent screen 4 and the shadow mask 5. The fluorescent screen 4 formed on the inner surface of the panel portion has a light absorbing strip 224 extending vertically without a cut. A large number of these are arranged in the horizontal direction, and
A plurality of fluorescent strips 225R (red), each of which has a different luminescent color from each other and which extends seamlessly over the entire vertical direction,
A large number of 25G (green) and 225B (blue) are arranged in a fixed order in the horizontal direction, and are arranged corresponding to the fluorescent screen 4 with a curved surface corresponding to the inner surface of the panel, and are arranged over the entire vertical direction. The slit-shaped through holes 228, which are elongated in the vertical direction corresponding to the fluorescent strips 225 extending without cuts, and which are formed in large numbers through the bridge portion 229 in the vertical direction, are arranged in a row at a predetermined pitch in the horizontal direction. The shadow mask 5 is shown.

Further, as another shape of the phosphor screen 4, as shown in FIG. 15, dot-shaped phosphor fine dots 226R (red), 226.
It has G (green), 226B (blue), and a light absorption film 227 filling the surroundings.

The shadow mask 5 is made of a steel plate material, an amber material having a small thermal expansion coefficient, or the like. Further, although not shown, the shadow mask 5 may be covered with, for example, bismuth, which suppresses thermal expansion. Further, instead of the slit-shaped through hole 228, a round through hole is also used.

Although the present invention has been specifically described based on the above embodiment, the present invention is not limited to the above embodiment and can be variously modified without departing from the scope of the invention. is there. For example, in FIGS. 1 and 2, it is desirable that the outer surface 15 of the panel portion 1 of the cathode ray tube 14 be completely sealed, but the effect of the present invention can be obtained even if the outer surface 15 is not necessarily completely sealed. For example, the supply nozzle 1 of FIG.
8, there may be a gap in the penetrating portion of the discharge nozzle 26, the supply nozzle 25 of FIG. Further, it goes without saying that the solution or coating applied to the outer surface 15 of the panel portion 1 of the cathode ray tube 14 can be applied to various solutions and coatings other than those shown in the above embodiment.

[0051]

As described above, according to the present invention,
Since the outer surface of the panel part of the cathode ray tube is sealed to form a coating film, the thickness of the entire surface to be coated is uniform, and there is no coating unevenness or foreign matter adhesion defects such as anti-reflection, antistatic or light selective absorption. It is possible to provide a cathode ray tube having a smooth coating film having various excellent functions on the outer surface of the panel portion.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional configuration diagram showing a positional relationship between a cathode ray tube and a closed container when a coating film is formed by a spin coating method which is an embodiment of the present invention.

FIG. 2 is a partial cross-sectional configuration diagram showing an arrangement relationship between a cathode ray tube and a closed container when a coating film is formed by a dip coating method which is another embodiment of the present invention.

FIG. 3 is a sectional view showing an embodiment of the color cathode ray tube of the present invention.

FIG. 4 is a sectional view showing a request for an electron gun of the present invention.

5 is a characteristic diagram of the electron gun shown in FIG.

FIG. 6 is a characteristic diagram of the electron gun shown in FIG.

FIG. 7 is a desired cross-sectional view of another example of the electron gun of the present invention.

FIG. 8 is a desired sectional view of still another example of the electron gun of the present invention.

FIG. 9 is a desired sectional view of still another example of the electron gun of the present invention.

FIG. 10 is a partially cutaway perspective view of still another example of the electron gun of the present invention.

FIG. 11 is a partially cutaway perspective view of still another example of the electron gun of the present invention.

FIG. 12 is a partially cutaway perspective view of still another example of the electron gun of the present invention.

FIG. 13 is a front view, a side view, a rear view and a plan view of still another example of the electron gun of the present invention.

FIG. 14 is a partially cutaway perspective view showing a demand for an example of a fluorescent screen and a shadow mask of the present invention.

FIG. 15 is a plan view showing a demand for another example of the phosphor screen of the present invention.

[Explanation of symbols]

1 ... Panel part, 2 ... Funnel part, 3 ... Neck part, 14
... cathode ray tube, 15 ... outer surface of panel portion, 16 ... coating having various functions, 17 ... closed container on outer surface of panel portion, 1
8 ... Solution for supplying film for forming film, 19 ... Solution for forming film, 20 ... Discharge port for solution for forming film, 21 ... Reinforcing metal fitting for cathode ray tube, 22 ... Arrow, 23 ... Solution tank for forming film, 24
... hermetically sealed container on the outer surface of the panel portion, 25 ... coating film forming solution supply nozzle, 26 ... overflow solution discharging pipe.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takao Kawamura 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory

Claims (1)

[Claims] 1. A cathode ray tube in which at least one layer of coating having a predetermined function is formed on the outer surface of a panel portion, the outer surface is sealed, and a solution for forming the coating is applied to the outer surface. A cathode ray tube having the above coating film formed thereon.