JPS58214268A - Cathode-ray tube for light source - Google Patents

Abstract

PURPOSE:To prevent any blister from developing in the aluminum film of a glass circumference wall during baking process by causing the inner surface of the circumference wall which is continuous with the face section of an encircling vacuum case to have a specified roughness. CONSTITUTION:The inner surface of a circumference wall 12 of an encircling vacuum case is formed rough, like ground glass. The roughness of the ground glass, although it varies according to the grain diameter of a phosphor 3 to be applied to some extent, is recommendably around 5-15mu. In applying the phosphor 3 by the conventional method, since the ground glass part of the inner surface of the circumference wall 12 has a large contact resistance with the phosphor surface, minute grains of the phosphor 3 adhere to the ground glass part. When a part of the minute phosphor grains is caused to adhere to the side wall part 12, pin holes (h) develop at the pointed ends of the fixed minute grains of the phosphor 3 after formation of a lacquer film 8 and an aluminum film 4. As a result, during backing process, the decomposition gas 13 of the lacquer film 8 scatters from the pin holes (h) without causing any blister in the aluminum film 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube for a light source used in display devices and the like.

With the diversification of displays, various giant display devices have been developed. A method suitable for color display and video reproduction is to replace each of the three primary color pictures with a single cathode ray tube, using tens to hundreds of thousands of cathode ray tubes. Such a cathode ray tube is called a light source cathode ray tube, and can also be described as a light emitting device. An example of its structure is shown in FIG. In the figure, (1) is a cylindrical glass tube body constituting the vacuum envelope, and its face (2) is equipped with one type of phosphor that emits green, blue, or red ( 3) is coated. The above phosphor (
An aluminum vapor-deposited film (4) called a so-called metal back is formed on the inner surface of the housing 8), and a graphite film (5) is further applied as an internal coating film for the purpose of electrical conduction. (6) is an electron gun for emitting electrons in response to a signal to cause a phosphor to emit light.

Next, the complete method for manufacturing such a cathode ray tube for a light source is shown in Figure 2 (a).
) to FIG. 20. First, the phosphor (
3) Clean the inner surface of the glass tube body (1) to be broken using an aqueous solution of hydrofluoric acid, hydroxide, an aqueous solution of IJ and pure water. Then, for example, a predetermined amount of an aqueous solution of barium acetate as an electrolyte is injected, and then a suspension of a predetermined phosphor (3) dispersed in an aqueous solution of water glass as an adhesive is injected, and the mixture is allowed to stand for a predetermined period of time. to precipitate the phosphor (3).

This state is shown in FIG. 2a. After the phosphor (3) has been precipitated in this way, the tube body (1) is tilted and the supernatant liquid (1j
) is discharged and dried with dehumidifying air to form a phosphor (3).
The coating is completely completed.

Such a method is generally called a sedimentation method.

After the phosphor (3) is deposited by the above method, the metal backing is performed, but if aluminum is vapor-deposited directly on the phosphor (8), a continuous vapor-deposited film will not be formed. After a very thin organic film was formed on (3), aluminum was vapor-deposited. That is, first, the phosphor surface is wetted with pure water, etc., and most of the phosphor (3) is coated with a water film (γ) as shown in Figure A2 (b), and then acrylic resin is used as the main component. An organic solvent lacquer such as toluene or ethyl acetate is sprayed to completely form a very thin lacquer film (8) on the water film (7). Next, lacquer film (8) on unnecessary areas.
- as shown in figure (c) - by pure water uO) flowing out of the nozzle (9) at a constant pressure. This is a phosphor (3
) If a lacquer film is formed on the unbroken area, the aluminum film deposited on this area will cause so-called blistering during the subsequent baking process, as shown in Figure 6, and will peel off from the glass wall. This is done to prevent.

Next, the fluorescent surface is dried using a dehumidifying air or the like, and a graphite film (5) 1 is applied to a predetermined area and dried in the same manner. Finally, aluminum is vapor-deposited to form an aluminum vapor-deposited film (4), and then the organic material used in forming the fluorescent surface is decomposed and removed by baking at about 400° C. to complete the formation of the fluorescent surface.

The tube body (1) on which the fluorescent surface has been formed is further welded and sealed with an electron gun (6), and then the tube body (1) is evacuated to a full vacuum to activate the electron gun (6). The finished product shown in FIG. 1 is obtained.

In the peripheral wall portion 112) commonly called the skirt portion of the light source cathode ray tube manufactured by the above method, an unnecessary area, that is, a phosphor (It) +l! In areas other than the phosphor screen, the lacquer film (8) is completely removed by pure water (110) flowing out at a constant pressure.
In order to reduce the remaining part of the phosphor (3) f
If you try to trim the area near the first layer with pure water (uo), the pure water may get into the adhered part of the phosphor (3) due to capillary development, or the lacquer film (8) may be pulled and cracked by the pure water. occurs. In order to prevent these inconveniences, if the trimming level with pure water α0) is lowered, the lacquer film (+8) on the peripheral wall will become larger, so the lacquer film (8) will be removed in that area during the above-mentioned baking process. ), the aluminum film (4) deposited in this region blisters as shown in FIG. 6 and peels off from the glass peripheral wall (end).

If this adheres to the upper part of the phosphor (3), the luminous efficiency will decrease, and if it adheres to the electron gun (6), it will cause sparks, etc. 1i1'.

The present invention has been made to solve the above-mentioned conventional problems, and an object of the present invention is to provide a cathode ray tube for a light source in which blistering of the aluminum film on the glass peripheral wall does not occur during the baking process.

Hereinafter, embodiments of the invention will be described with reference to all the drawings.

In FIG. 4, the glass tube body (1) has a circumferential wall (b) continuous from its face portion (2) whose inner surface has a predetermined length, for example, the diameter of the glass tube body (1) is about 25 mm. If the length is approximately 20-1), 6 μm to 80 μmR
It is formed to have a roughness of Z.

That is, a part of the phosphor is coated on the peripheral wall part (commonly called the skirt part) other than the phosphor-coated part of the face part (2) of the light source cathode ray tube, and a lacquer film ( 8), which enables the dispersion of decomposed gas.

In other words, part of the particulate phosphor is adhered to the peripheral wall portion of the face portion other than the portion to which the phosphor is adhered.

Conventionally, a cylindrical glass tube with a diameter of about 2.5 m has a part to which a phosphor (3), called a face part (2), is attached on either side, and the peripheral wall of the tube is a straight pipe, so the face part ( 2)
Since the glass surface is perpendicular to the peripheral wall and has no irregularities, it is a smooth surface, so it was not possible to adhere the phosphor to the peripheral wall using the sedimentation method. The inner surface of the portion (12) is formed to have an uneven roughness, that is, a ground glass shape.

There are various ways to make the inner surface of the peripheral wall (support) into a ground glass state, such as etching in an aqueous hydrofluoric acid solution or sandblasting, but in this example, the ground glass state was obtained by sandblasting. did.

The size of the unevenness of the ground glass varies somewhat depending on the particle size of the phosphor (3) to be adhered, but it is preferably around 5 to 15 μm. Also, the dimensions of the ground glass portion are from the face to 20W, and the side wall beyond that remains the same as before, with no irregularities and a smooth surface.

The method for depositing the phosphor is the same as the conventional method; first, the inner surface of the tube body (1) to which the phosphor (3) is to be completely deposited is injected with an aqueous solution of hydrofluoric acid, and then an aqueous solution of barium acetate is injected into the entire tube. After injecting 0.05% of the total liquid volume, the predetermined phosphor (3) and Sif2mN in the water glass aqueous solution are injected into the tube line ri, the amount Ll,
A suspension of a mixed fraction adjusted to 7% was injected and allowed to stand for about 15 minutes to precipitate the phosphor (3). In this case, the contact resistance with the surface of the phosphor is small on the ground glass inner surface of the peripheral wall, so that the phosphor fine particles adhere thereto. After the phosphor is precipitated, the tube body (1)
to complete the deposition of the phosphor (3). At this time, the particulate phosphor is adhered to and remains on the peripheral wall side. Subsequent lacquer film (8) formation step, aluminum film (4)
) The forming process is no different from the conventional method.

When a part of the particulate phosphor adheres to the side wall portion (2) as described above, as shown in FIG. A pinhole (h) will be formed at the tip. Therefore, during the baking process, the decomposition gas (from) of the lacquer film scatters through the pinholes (h) without causing blisters to the luminium film.

The above embodiment describes a straight tube type negative ray tube for a light source having a diameter of approximately 25 sides, but the cathode ray tube for a light source according to the present invention may have a face portion having various shapes as long as it has the entire peripheral wall as a light source element. It can be applied to things. Also,
Fluorescent material on the surrounding wall? As a temporary adhesion method, it can be applied to all precipitation coatings other than the combination of barium acetate and water glass.

As explained above, according to the cathode ray tube for a light source according to the present invention, blistering of the lumenium film on the side wall due to decomposition gas of the lacquer film in the baking process is eliminated, and the aluminum film is removed in the subsequent process. Problems such as lower brightness of the fluorescent surface due to peeling and sparks caused by adhesion to the electron gun are eliminated, making a significant contribution to improving process yield and reliability.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of an example of a cathode ray tube for a light source, and Figure 2 (
Figures a) to 2(0) are explanatory diagrams of the manufacturing process of a cathode ray tube for a light source, Figure 6 is a cross-sectional view of the main part showing the blistered state of the aluminum film after the baking process, and Figure 4 is a diagram showing the process of manufacturing a cathode ray tube for a light source. FIG. 5 is an enlarged view of the peripheral wall of such a negative ray tube made into ground glass and coated with a phosphor. The phosphor is coated on the peripheral wall and the decomposition gas of the lacquer film causes blisters on the aluminum film during the baking process. FIG. 2 is an explanatory diagram showing a state in which the particles scatter without causing any damage. (1)... Glass tube body, (2)... Face portion, (3)... Fluorescent body (support)... Surrounding wall portion. - Agent Shinichi Kuzuno (1 other person) 11th m 2nd a) Figure 2 (b)

Claims (1)

[Claims] (1) A cathode ray tube for a light source, which has a fluorescent surface on at least one face portion of the tube body of a glass tube constituting a vacuum envelope, and has an electron gun sealed on the other end, and has a fluorescent material on the face portion. In a cathode ray tube for a light source, which is coated with sedimentation coating, the inner surface of the peripheral wall of the vacuum envelope continuous from the face part f: 3μ
A cathode ray tube for a light source, characterized in that the unevenness is formed to have a roughness of m to 80 μm RZ.