JPH02100235A - Manufacture of color picture tube - Google Patents

Abstract

PURPOSE:To prevent color purity deterioration such as color shift and color shading by forming an electron absorbing layer precisely and easily in a desired position of a shadow mask within a color picture tube. CONSTITUTION:The formation of electron absorbing layers 33a, 33b on a shadow mask 31 of a color picture tube comprises a step of coating the shadow mask 31 with a sensitizing agent, a step of exposing the sensitizing film in an unnecessary part of the electron absorbing layers 33a, 33b to light to harden said film, and a step of developing and removing the sensitizing film in the non-sensitized part. Further, it comprises a step of coating the electron absorbing layer 33a, 33b, a step of removing the hardened sensitizing film and the electron absorbing layer 33a, 33b present thereon, and a step of subjecting the shadow mask 31 to a thermal treatment. According to such manufacturing method of the color picture image, the electron absorbing layer can be precisely and easily formed in a desired position of the shadow mask. Hence, the displacement of electron beams by dreaming can be effectively corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a method of manufacturing a shadow mask type color picture tube, and particularly to a method of manufacturing the shadow mask.

(Prior art) In general, the shadow mask of a color picture tube is used to prevent doming, which occurs when the picture tube is in the early stages of operation, when a high-brightness image is projected in some areas, and especially when the high-brightness image part is stopped for a certain period of time. It is known that it causes color purity and deteriorates color purity.

With respect to such doming of color picture tubes, proposals have been made to electrostatically correct and reduce the mislanding of electron beams that accompanies doming. For example, JP-A-60-148036 or JP-A-60
Publication No. 195846 discloses a technique in which an electron absorption layer made of lead borate glass containing tin oxide (Sn02) is formed on the electron gun side of a shadow mask, or a low conductivity layer is further provided thereon. ing. Also, JP-A-62-1
Japanese Patent No. 88135 discloses a technique in which an electron absorption layer is provided on the wall surface of each through hole of a shadow mask on the side of the central axis of the shadow mask. That is, as shown in FIG. 5, the electron beam (33) in a state where the shadow mask (34) does not cause the doming phenomenon lands at a predetermined position (33a) on the fluorescent screen (32). Here, if the electron beam density incident on the shadow mask increases,
When the shadow mask is heated and a doming phenomenon occurs, that is, the electron beam (36) in a heated state where the shadow mask is located at (35) moves in the direction of the tube axis (31) as the shadow mask is domed. , the landing point of the electron beam also changes from position (33a) to position (36a).
>Move to. That is, the electron beam that should have landed at the original position (33a) mislanded at the tube axis side position (36a) due to the doming phenomenon, and the amount of mislanding at positions (33a> and (36a)) If the limit of landing margin due to group arrangement is exceeded, color purity will deteriorate.Figure 3 shows the method disclosed in Japanese Unexamined Patent Publication No. 60-1/18036 or Japanese Unexamined Patent Publication No. 60-60.
This is an enlarged view of the vicinity of the through-hole of the shadow mask shown in Publication No. 195846, since an electron absorption layer (33) is formed on the main surface of the shadow mask (31) on the electron gun side. , an electron absorption layer (33
) will be negatively charged.

As a result of this negative charging, an equipotential distribution (3
4) is generated, and due to this decelerating electric field, the electron beam (35) receives a force F in the direction of the arrow in the figure, so that the electron beam (35a) changes its trajectory in a direction away from the tube axis. FIG. 2 is an enlarged view of the vicinity of the through-hole of the shadow mask shown in Japanese Patent Application Laid-Open No. 62-188135@. ) on the wall on the tube axis side (33a).
, (33b) are formed, so that it is negatively charged depending on the electron flow density by an electron beam or secondary electrons from a fluorescent screen or the like. As a result of this negative charging, an electric field similar to an equipotential distribution (34) is generated on the electron gun side of the shadow mask (31) and in the vicinity of the through hole (32), and this electric field causes the electron beam (35) to Since the electron beam (35a) receives a force F in the direction of the arrow in the figure, its trajectory is changed in a direction away from the tube axis.

However, although the former method of providing an electron absorption layer on the main surface of the shadow mask on the electron gun side was effective against mislanding at the initial stage of operation of the color picture tube,
It was not possible to sufficiently correct mislanding due to local doming of the shadow mask. In addition, in the latter method, in which an electron absorption layer is also provided on the wall surface on the tube axis side of the through hole of the shadow mask, the electron absorption layer is formed by the following method, so the following is achieved in terms of manufacturing and characteristics. There was a problem like this.

That is, in FIG. 2, before the panel and the funnel are sealed, for example, crystalline lead borate glass dissolved in a butyl acetate alcohol solution containing several percent of nitrocellulose is used in the electron gun of the shadow mask (31). Side main surface (31a
) and the center side wall surface (31b) of the through hole (32), and a shadow mask (31) coated with this crystalline lead borate glass is attached to the panel. After that, the panel and No. 1
Place the tunnel on the designated frame and the maximum temperature will be approximately 400'C.
By passing it through a furnace with a holding time of at least 35 minutes to crystallize the lead borate glass, the conductivity becomes approximately 10-
120-1. A lead borate glass layer with a low conductivity of m-1 is formed on the main surface (31a) of the shadow mask (31) on the electron gun side and on the center side wall surface (31b) of the through hole (32).

This glass layer can be applied by, for example, forming a large number of through holes by ordinary etching means, press-molding, and then spraying. In order to form an electron absorption layer on the main surface of the shadow mask on the electron gun side (small hole side) and the central wall surface of the through hole, conventionally, as shown in FIG. The spray nozzle (40a) is arranged approximately perpendicularly to the shadow mask (31) so that it can move vertically, horizontally, and the spray nozzle (40b) on the screen side (large hole side) The electron-absorbing layer was formed by spray coating the electron-absorbing layer by placing it diagonally from the periphery toward the center.However, when trying to form the electron-absorbing layer on the wall on the center side of the hole using this method, In reality, as shown in FIG. 4, an electron absorption layer (33
c) is formed. Figure 4 shows an enlarged view of the vicinity of the hole in the shadow mask when an electron absorption layer is formed on the main surface on the electron gun side of the shadow mask, the center side wall surface of the hole, and the main surface on the screen side. As shown in the figure, these electron absorption layers are
Due to secondary electrons, it becomes negatively charged depending on the electron flow density.

Along with this negative charging, an electric field like an equipotential distribution (34) is generated on the electron gun side and the screen side of the Shitodo mask (31) and in the vicinity of the through hole (32), and this electric field causes the electron beam (35) to is subjected to a force F that is deflected in the direction of the arrow in the figure.

As can be seen from the figure, the electric field (34a) on the electron gun side of the shadow mask (31) is a deceleration electric field, and also in the area of the through hole (32), as seen by the beam flux passing through the through hole (32). Mislanding due to doming of the shadow mask (31) is prevented by repulsion from the electron absorption layer <33b) formed on the center side wall surface (31b) and suction from the wall surface (33d) opposite to the center side wall surface (31b). deflected in a direction that cancels out. But shadow mask (31)
Since the electric field (34b) on the screen side becomes an accelerating electric field, there is a problem in that the deflection effect that offsets mislanding in the electron gun side region and through-hole region of the shadow mask (31) is reduced.

(Problems to be Solved by the Invention) As described above, in the conventional method, when an electron absorption layer is formed on the electron gun side main surface of the shadow mask in a color picture tube and on the tube axis side wall surface of the through hole, it is difficult to form an electron absorption layer in an undesired place. There was a problem in that an electron absorption layer was formed on the substrate, and as a result, mislanding could not be prevented.

The present invention has been made to solve the above-mentioned problems, and provides a method for manufacturing a color picture tube in which an electron absorption layer can be accurately and easily formed at a desired location of a shadow mask in a color picture tube. It is something.

[Structure of the invention]

(Means for Solving the Problems) When forming an electron absorption layer on a shadow mask of a color picture tube, the present invention includes a process of applying a photosensitive agent to the shadow mask and removing a photoresist film on unnecessary portions of the electron absorption layer. A step of exposing and curing, a step of removing the photoresist film in the unexposed area by phenomenon, a step of applying an electron absorption layer, and a step of removing the cured photoresist film and the electron absorption layer existing thereon. and a step of heat-treating a shadow mask.

(Function) According to this method of manufacturing a color picture tube, it is possible to easily form exactly one electron absorption layer at a desired location on the shadow mask, thereby making it possible to more effectively suppress the displacement of electron beams due to doming. A color picture tube that can be corrected can be obtained.

(Example) An embodiment of the present invention will be described below.

FIG. 1 shows a cross-sectional view of a color picture tube according to the present invention. As is clear from FIG. 1, the vacuum envelope is composed of a panel (1) whose front portion has a substantially rectangular outer shape, a funnel-shaped funnel (2), and a neck (3). A fluorescent screen (4) consisting of a striped phosphor layer that emits red, green, and blue light is adhered to the inner surface of the panel (1), and the neck (3) of the panel (1) Arranged in a row along the horizontal axis, red,
A so-called in-line electron gun (6) that emits three electron beams (5) corresponding to green and blue is provided.

In addition, at a position close to and facing the fluorescent screen (4),
A shadow mask (31) having a curved effective surface in which a large number of slit-like through holes are arranged vertically and a large number of vertically arranged holes are arranged horizontally is supported and fixed by a mask frame (8). Rough mask frame (8
) is supported within the panel by being locked by a stud pin (10) embedded in the inner wall of the upright end of the panel (1) via an elastic member (9).

Three in-line arrayed electron beams (5) are deflected by a deflection device (12) external to the funnel (2) and scan a rectangular area corresponding to the rectangular panel (1) and a shadow mask. By passing through the through hole (31), the light is selected and lands on the striped phosphor layer, thereby reproducing a color image.

In addition, the electron beam is affected by external magnetic fields such as the earth's magnetism, so it may not land accurately on the striped phosphor layer.In order to prevent the color purity of the reproduced image from deteriorating, a ferromagnetic material is installed inside the funnel (2). A magnetic shield (11) made of a metal plate is secured via a frame (8).

The shadow mask (31) disposed close to and facing the fluorescent screen (4) has a coefficient of thermal expansion of 1.2xlO-5/
It is formed from a thin plate with a thickness of 0.1 mm to 0.3 mm made of so-called cold-rolled steel whose main component is iron. As shown in FIG. 2, the wall surface is coated with an electron absorption layer (33al (33b
) are sealed and bonded by high-temperature heat treatment.

Next, a method for forming this electron absorption layer will be explained.

After the shadow mask on a flat plate with holes is cut into a predetermined shape, its peripheral edge is held between a blank holder and a die, and the main surface with the holes is cut into a predetermined curved surface by an upper punch and a lower knockout. The peripheral edge portion is then bent and formed, for example, along the tube axis direction as a skirt portion for supporting and fixing the main surface of the mask.

A photosensitive agent, for example, a photosensitive solution consisting of alkali milk caseinate and ammonium dichromate, is applied to both sides of the shadow mask thus formed, and dried to form a photosensitive resin film (hereinafter referred to as a resist film). ).

Here, the methods of applying the photosensitive liquid include dipping method, spray method,
A spin method may be considered, but a dipping method is most appropriate in consideration of uniformity of the film, simplification of process equipment, etc.

Next, as shown in FIG. 7(a), the resist film applied to the shadow mask (31) is exposed and cured by an ultra-high pressure mercury lamp (50) placed at the upper center of the shadow mask (31). FIG. 7(b) is an enlarged cross-sectional view of the part marked A in FIG. The resist film (39a) on (31a) and the resist film (39b) on the center side wall surface (31b) of the through hole are not exposed.
The resist film (39
Resist film (39d) on the wall surface (31d) opposite to C)
) will be exposed.

Here, FIG. 7(C) is an enlarged perspective view of the part marked 8 in FIG. 7(a) from the upper center of the shadow mask (31). At this time, if the exposure lamp is used as a point light source,
Since the lamp light (51) enters from the direction of the central axis of the shadow mask, not all of the resist film (39d) coated on the opposite wall surface (31d) is exposed, as shown in the figure, but some of the resist film (39d) is not exposed. There will be parts that are not.

Of course, use an ultra-high pressure mercury lamp (50) with a shadow mask (
31) by moving it upward away from the opposite wall surface (31).
The entire surface of the resist film (39d) coated on 1d) can be irradiated with lamp light (51), but if the ultra-high pressure mercury lamp (50) is placed too far away from the shadow mask (31), the lamp light (51) ) enters the shadow mask (31) at an angle close to parallel to the tube axis (52), so the resist film (39b) on the center side wall surface (31b) is also irradiated. Therefore, as shown in FIG. 7(a), it is appropriate to use a long light source for the ultra-high pressure mercury lamp (50).
Its length ([p) should be 1/4 or more of the short side length (LV) of the shadow mask (31), and the height (H) of the shadow mask (31) should be set at the top center of the shadow mask (31). 1/8 to 1/8 of the length ([h) in the long side direction of the mask (31)
It is preferable to reduce the amount to 1/2. By doing this, the resist film (39a) on the small hole side main surface (31a) of the shadow mask (31) and the resist film (39b) on the center side wall surface (31b) of the through hole are not exposed to light. In the entire region of the shadow mask (31), the resist film (39c) on the main surface (31c) on the large hole side and the resist film (39d) on the opposite wall surface (31d) can be exposed.

However, the ultra-high pressure mercury lamp (50) has a shadow mask (
31) Shadow mask (3
Since the lamp light (51) is irradiated at a substantially right angle near the center of 1), the resist films on both wall surfaces of the through hole are exposed.

Next, the resist film is decomposed with hot water, etc., but the resist film (39
a) and the resist film (3) on the center side wall surface (31b) of the through hole.
9b) was removed and the resist film (3
9C) and the resist film (39d) on the opposite wall surface (31d).
) remains attached to the shadow mask (31).

Then, as shown in Figure 6, the small holes of the shadow mask (31) are filled with crystalline lead borate glass dissolved in acetic butyl alcohol solution containing several percent of nitrocellulose. A spray nozzle (40a) disposed on the side and a spray nozzle (40b) disposed diagonally from the periphery toward the center of the shadow mask (31) are used to spray and dry the large hole side. At this time, the spray nozzle (40b) on the large hole side may be arranged so as to be approximately perpendicular to the curved surface of the shadow mask (31).

Next, the resist film is exposed to light using a decomposing agent such as sulfamic acid, and the crystalline lead film attached thereto is 1
! ! Remove the di-salt glass, then the maximum temperature is 400°
The main surface (31a) on the small hole side of the shadow mask (31) is crystallized by passing it through a furnace with a holding time of 35 minutes or more at C to crystallize the lead-filled M salt glass.
and an electron absorption layer (33a) only on the center side wall surface (31b),
(33b) can be formed.

Here, the process of removing the photosensitive resist film and the lead-borate glass on it using a decomposing agent is omitted, and the resist film is incinerated by directly inputting it into a heat treatment process after coating the lead-borate glass. Although it is possible to remove unnecessary lead borate glass by using a method, in order to completely remove it, it is still preferable to provide a step that uses a decomposing agent.

However, as mentioned above, when exposing the resist film, the resist film on both the left and right walls of the through hole (32) is exposed near the center of the shadow mask (31), so as a result, the resist film on both the left and right walls of the through hole (32) is exposed. No electron absorption layer is formed, and it is formed only on the main surface on the electron gun side. However, the displacement of the electron beam caused by doming of the shadow mask is hardly a problem near the center of the shadow mask, and it is sufficient to have an electron absorption layer on the main surface on the electron gun side, and There's no need.

The thus completed shadow mask (31) is assembled with a panel and subjected to a screen forming process.

First, an azide-based resist film is formed on the inner surface of the panel, and exposed to light using an ultra-high pressure mercury lamp through the through hole (32) of the shadow mask (31). After developing the resist film, graphite is applied, dried, and developed using a decomposing agent to form light-absorbing stripes at predetermined positions on the inner surface of the panel.

Next, a slurry in which phosphor particles, for example blue phosphor particles, are added to a photosensitive resin liquid is applied to the inner surface of the panel, and exposed and developed in the same manner to form blue luminescent stripes. Thereafter, a screen is formed by sequentially forming green and red light emitting phosphor strips in the same manner. The panel structure completed as described above is
A color picture tube is obtained by joining the funnel and frit glass, sealing the exhaust, and going through a predetermined process.

The results of experiments conducted by the present inventors regarding the purity drift characteristics of the 28-inch color picture tube thus obtained are as follows.

As the reproduced screen patterns, the full white pattern shown in FIG. 8 and the partially white pattern shown in FIG. 9 were used. In Figure 9, the horizontal width i
A 00 m long strip (51) is reproduced on the screen so that it is positioned in two places on the left and right, each spaced 180# from the center.

The remaining part is black, ie, a non-luminescent part. X marks indicate measurement points. Table 1 shows the measurement results of the amount of beam movement. The measurement conditions are anode voltage Eb = 29kV, cathode current IK is 1500μ in pattern (A) and 1600μ in pattern (B).
I made it eight.

Table 1 In the same table, the comparative amount (A) refers to the amount of tin oxide (8 holes 02
) is a 28-inch color picture tube with an electron-absorbing element made of lead-bolate glass.
This is a 28-inch color picture tube in which an electron absorption layer is formed on the center side wall surface of the through hole of the shadow mask and on the main surface on the fluorescent screen side using the conventional manufacturing method shown in the figure. Therefore, it was confirmed that the purity drift characteristics of the color picture tube produced by the manufacturing method of the present invention are better than those of the conventional color picture tube and the color picture tube obtained by the conventional manufacturing method. This is because the method for manufacturing a color picture tube of the present invention forms the electron absorption layer only in the portion necessary for doming the shadow mask, thereby more effectively correcting the displacement of the electron beam.

Although crystalline lead borate glass is used as the electron absorption layer in the present invention, the object of the present invention can also be sufficiently achieved using other materials such as zirconia alkoxide compounds, ZrSi (octla), etc. Can be done.

(Effects of the Invention) As described above, according to the present invention, colors such as color shift and color unevenness can be sufficiently prevented over the entire screen not only during the initial operation of a color picture tube but also during localized or short-time large currents on the screen. A color picture tube that can prevent purity deterioration can be obtained.

[Brief Description of the Drawings] Fig. 1 is a schematic cross-sectional view of a color picture tube for explaining the present invention, and Fig. 2 is an enlarged view of the shadow mask through hole obtained by the manufacturing method of the present invention. FIGS. 3 and 4 are schematic diagrams illustrating electrostatic deflection of a beam, and FIGS. 3 and 4 are schematic diagrams illustrating electrostatic deflection of a beam, with enlarged through holes of a shadow mask obtained by a conventional manufacturing method. FIG. A schematic diagram to explain the movement of an electron beam due to doming. Figure 6 is a schematic diagram of spray coating an electron absorption layer on a shadow mask. Figure 7 (a) is a diagram showing the exposure of a resist film coated on a shadow mask. Schematic diagram when
FIG. 7(b) is a schematic diagram showing an enlarged view of the shadow mask through hole in FIG. 7(a), and FIG. 7(C) is a perspective view showing an enlarged view of the shadow mask through hole in FIG. 7(a). Figures 8 and 9
The figure is a reproduced image pattern diagram illustrating the purity drift characteristics of a color picture tube obtained by the manufacturing method of the present invention. Agent Patent attorney Nori Ken Yudo Takehana Kikuo Figure 1 → V knowledge side S2 Figure Figure

Claims (1)

[Claims] (1) A phosphor screen, an electron gun that emits an electron beam that selectively causes the phosphor of the screen to emit light;
A method for manufacturing a color picture tube, comprising: a shadow mask disposed close to the screen, having a large number of through holes, and having an electron absorption layer on its surface, the shadow mask having a large number of through holes. a step of forming the shadow mask into a predetermined shape; a step of forming a photosensitive resin layer on the surface of the shadow mask; a step of exposing and curing the photosensitive resin layer; a step of removing an unexposed portion of the transparent resin layer; and a step of forming an electron absorption layer on the surface of the shadow mask.
A method for manufacturing a color picture tube, comprising the step of heat-treating the shadow mask.