JPS60257040A - Producing method for light source cathode-ray tube - Google Patents

Abstract

PURPOSE:To prevent a blister on the aluminum film of a circumferential wall of glass, by beginning to heat a tube main body after raising the temperature of it to the preset degree by the remaining heat of the preceding heating, not heating the said body immediately when it is carried in a firing room. CONSTITUTION:After a tube main body 1 is carried in a firing room 33 and screened by a parting door 37, the tube main body 1 is heated by the remaining heat of the preceding heating, and the regular heating is delayed by timer-control. In this way, it is prevented that a blister is made on an aluminum film in the baking precess, because a temperature rising curve around the temperature of 200-300 deg.C, where a large quantity of decomposed gas is scattered, is made gentle, and the decomposed gas is scattered little by little.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for manufacturing a cathode ray tube for a light source used in a display device or the like.

[Prior Art] With the diversification of displays, various giant display devices have been developed. For example, as a means suitable for color display and moving image reproduction, there is a method that replaces each of the picture elements of the three primary colors with a single cathode ray tube, and uses tens 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 element. An example of its structure is shown in FIG.

In Fig. 1, (1) is the cylindrical glass tube body that constitutes the vacuum envelope, and on the inner surface of its face (2) is a fluorescent screen that emits green, blue, or red light ( 3)
is formed. On the inner surface of the phosphor screen (3), there is an aluminum vapor deposited film (4) called a metal back.
is formed, and a graphite film (5) is further applied as an internal conductive film for the purpose of electrical conduction. (8)
is an electron gun that emits electrons in response to a signal to cause the fluorescent screen (3) to emit light.

Next, a method for manufacturing a cathode ray tube for a light source is shown in Figure 2 (a).
), , (b), and (c). As shown in FIG. 2(a), first, the inner surface of the glass tube body (+) on which the phosphor (3a) is to be coated is coated with a hydrofluoric acid aqueous solution.
Wash using a water-resistant sodium aqueous solution and pure water.

Next, 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 (3a) dispersed in an aqueous solution of water glass as an adhesive is injected for a predetermined period of time. It is left standing to allow the phosphor (3a) to settle. After precipitation of the phosphor (3a), slowly tilt the tube body (+) to drain the clear liquid and dry it with dehumidifying air to prevent the phosphor (3a) from adhering to the face part (2). Complete. This method is generally called the precipitation method, and after the phosphor (3a) is deposited by this precipitation method, a metal back is applied, which involves directly depositing aluminum on the phosphor screen (3). Then, since a continuous vapor deposition film is not formed, a very thin organic film is formed on the second side of the phosphor screen (3) for filming, and then aluminum is vapor-deposited.

That is, as shown in Fig. 2(b), first the fluorescent screen ・(3
) is wetted with pure water, etc., and most of the phosphor (3a) is covered with a water film (7), and then an organic solvent lacquer such as toluene or ethyl acetate containing acrylic resin as the main component is sprayed. , very thin lacquer coating 11 on -1- of water nri (7)! (
8). Next, a lacquer coating (8) is applied using a nozzle (
Pure water (21) is jetted out at a constant pressure from the hole (23) in
0). This is because when a lacquer film (8) is formed on an area where the phosphor (3a) is not coated, the aluminum evaporated film (4) deposited on this area causes blisters during the subsequent baking process, and the peripheral wall (22) This is done to prevent it from peeling off.

Next, the phosphor screen (3) is dried using a dehumidifying air or the like, and a graphite film (5) is applied to a predetermined area, which is similarly dried. Finally, perform aluminum vapor deposition, Aluminum Vapor Deposition 11! After forming (4), the organic material used in forming the phosphor screen is decomposed and removed by a baking process in which it is heated to 400 to 420° C., thereby completing the formation of the phosphor screen (3). The tube body (1) on which the phosphor screen (3) has been formed is further sealed with the electron gun (6) shown in Figure 1, and then the inside of the tube body (1) is evacuated to release electrons. Activate the gun (6) to obtain a light source cathode ray tube.

As shown in FIG. 3, in the method described above, the baking process is different from that for ordinary cathode ray tubes. In other words, the intermittent drive firing process as shown in FIG. 3 is performed for the purpose of reducing the size of the objects to be fired, mass processing, reducing the installation area and volume of the furnace, and saving energy.

In FIG. 3, the tube body (1) on which the aluminum vapor deposited film (4) has been formed is placed on a baking jig (31), placed at the baking furnace entrance (32), and placed in the baking chamber (33) in units of several hundred tubes. ) by a drive belt (313). At this time, the partition doors (37), (37), (
3? ) simultaneously moves upward and is released. When the tube body (1) is placed in the firing chamber (33) by transportation, the partition door (
37), (37), and (3?) are all lowered to their original positions, and firing begins from there. The firing temperature curve at this time is shown in FIG. 4(a). The tube body (1) thus fired for a predetermined period of time is then conveyed to the cooling chamber (34) by the drive belt (3B). At this time, it goes without saying that the partition doors (37), (3?), and (37) move upward and are in the open state. At the same time, the next several hundred tube bodies (1) placed at the inlet (32) are placed in the firing chamber (33), and are then fired in the same manner as described above. At this time, the tube body (1) of the firing chamber (34) is cooled for the same time as the firing process is performed. When the firing process is completed in this way, the tube body (1) of the cooling chamber (34) is transferred to the outlet (35), and the tube body (1) of the firing chamber (33) is transferred to the outlet (35).
) enters the baking chamber (34), and the tube body (1) at the inlet (32) enters the baking chamber (33), and the same process is repeated to complete the baking process.

As shown in FIG. 5, the thermal decomposition characteristics of an ordinary organic coating mainly composed of acrylic resin generate a large amount of decomposed gas at temperatures of 200 to 300°C. However, with the current baking process, as can be seen from the temperature curve in Figure 4 (a),
Since the temperature is raised much more severely than in a normal cathode ray tube, many thermal decomposition gases from the lacquer coating remaining on the peripheral wall (22) of the tube body (1) are generated. As a result, the peripheral wall of the tube body (1) (see Fig. 2 (C) f!
- As shown in Figure 6, the aluminum vapor deposited film (4) of (22) has blistered and the surrounding wall of the glass (22)
). Because fluorescent screen (3)
In the part where the phosphor (3a) is adhered, there are countless protrusions of the phosphor (3a) particles, and the aluminum evaporated film (4) has innumerable pinholes due to the protrusions. Therefore,
At the phosphor (3a) adhered part, the decomposed gas of the lacquer film (8) is diffused through the aforementioned pinhole, but the surrounding wall ffl (22
), there is almost no adhesion of the phosphor (3a), and the lacquer film (8) is directly deposited on the glass wall soil, and the aluminum evaporated film (4) is further deposited on top of it, so rapid decomposition occurs. Due to gas diffusion, aluminum vapor deposition film (4)
This can lead to blisters.

Due to the causes mentioned above, the aluminum vapor deposited film (4) causes blisters, peels off from the glass peripheral wall (22), and if this sticks to the phosphor screen (3), the luminous efficiency may decrease or If the electron gun (6) is old, it may cause problems such as causing sparks.

[Summary of the Invention] The present invention was made in order to eliminate the drawbacks of the prior art described in section 2, and is to relax the heating temperature rise curve in the intermittent drive firing method in the baking process. In other words, in the past, heating started immediately when the tube body was brought into the firing chamber;
Even if it is heated, do not heat it immediately, but let it rise to a certain temperature by preheating from the previous heating.1 When the predetermined temperature is reached, heating will start, causing blistering of the aluminum film on the glass peripheral wall. An object of the present invention is to provide a method for manufacturing a cathode ray tube for a light source.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to the drawings. In addition, in the following explanation, the same 1 as the prior art described in -
The explanation regarding the minutes will be omitted.

A feature of the embodiment of the present invention is that in the intermittent drive firing processing method, the start of heating in the firing chamber (see FIG. 3) (33) is delayed by timer control. In other words, after the tube bodies (I)'' are carried into the firing chamber (33) and blocked by the partition door (37), the tube bodies (1) are heated by the previous heating preheating, and the full-scale heating is started by a timer. Heating is delayed by control to a temperature range of 2° to 300'C that dissipates into the natural enemy of decomposed gas shown in Figure 5. - The rising curve is made gentler, and the decomposed gas is dispersed little by little, and the heating is performed in the baking process. This eliminates blisters on the aluminum coating.

That is, in the conventional technology, the tube body (1) is heated immediately after being brought into the firing chamber (33), but in this embodiment, the tube body (1) is heated immediately after being brought into the firing chamber (33). After loading,
No heating was applied for 10 minutes, only preheating was performed, and full-scale heating was applied after the tube body (1) reached t o -150'0. Heating temperature t at this time
The lh line is shown in FIG. 4(b).

Note that the other manufacturing steps 1-1 are the same as those in the prior art described in 2), so the explanation thereof will be omitted. In addition, in the above example, the start of heating in the firing chamber was delayed for 10 minutes, but if the time is shorter than this, the effect of preventing blistering of the aluminum vapor-deposited film will be reduced, and if the time is long, the effect will be even more effective. However, this example had the disadvantage of increasing the processing time, so this example was the best.

Although a gas firing furnace was used in this embodiment, a similar effect can be obtained using an electric firing furnace. Furthermore, the baking process of the intermittent drive baking process can be applied not only to the baking process for cathode ray tubes for light sources, but also to other cathode ray tubes.

[Effects of the Invention] According to the invention described above, in the baking process, the rate of dissipation of the decomposed gas of the lacquer film is reduced, the occurrence of blistering of the aluminum vapor deposition film is eliminated, and the phosphor screen due to peeling of the aluminum vapor deposition film is eliminated. Defects such as reduced brightness and sparks are eliminated, improving process yield and reliability.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an example of a cathode ray tube for a light source. Figures 2 (a) to (C) are explanatory diagrams of the conventional manufacturing process of cathode ray tubes for light sources, Figure 3 is a simplified diagram showing an intermittent drive firing furnace, Figure 4 is a heating temperature curve, and Figure 5 is a lacquer FIG. 6 is a graph showing the decomposition rate of the coating film, and is a simplified diagram showing the blistering state of the aluminum vapor deposited film. (1)...Pipe body, (2)...Face part, (3)
... Fluorescent screen, (4) ... Metal back, (8) ...
・Lacquer coating, (31)...Baking jig, (33)...
- Firing chamber, (34)...cooling chamber. Note that the same reference numerals in the figures indicate the same or equivalent parts. - Agent Masuo Oiwa Figure 3 Figure 4 Figure 11 60-257040 (b) 51st Figure 6

Claims (1)

[Claims] (1) A phosphor screen is formed on the inner face of at least one end of the glass tube body that constitutes the vacuum envelope, and a lacquer film made of an organic solvent containing acrylic resin as the main component is formed on the phosphor screen. Then, after applying a metal back to the lacquer coating mentioned above, a firing chamber and a cooling chamber are provided, each having an independent chamber, and the tube body is placed on the firing chamber, and the tube body is sequentially and intermittently transferred from the firing chamber to the cooling chamber. In the method for manufacturing a cathode ray tube for a light source, in which the lacquer coating Q is decomposed and removed by an intermittent drive heating and firing furnace, the firing chamber heating step of the intermittent drive heating and firing furnace is performed after the tube body is placed in the heating step. A method for manufacturing a cathode ray tube for a light source, characterized in that a heating operation is started after a predetermined period of time has elapsed.