JPS6319736A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE:To realize stability against external impact, by forming a body for supporting a shadow mask with a mobile piece fitted to a panel pin, and a piece fixed on a mask frame whose thickness is larger than that of the mobile piece and in excess of a specific value. CONSTITUTION:A shadow mask 6 fixed with a mask frame 5 is disposed close to a fluorescent screen 3 mounted on a front panel 2 of an enclosure, to compose a color cathode-ray tube. Namely, an elastic support 20 for supporting the shadow mask 6 is formed by unitedly fixing a bent-shaped mobile piece 22, which can be freely assembled/disassembled and fitted to a pin 15 on the panel 2, and a fixing piece 21, which is 1.5 or more times as thick as the mobile piece 22 and is fixed with the mask frame 5. Color shift of the screen is then prevented from occurring due to thermal expansion of the shadow mask 6 when the cathode-ray tube being in operation, and besides external impact is absorbed. Hence, the cathode ray-tube can be obtained having its screen quality widely stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a color picture tube, and more particularly to a color picture tube with an improved support for supporting a shadow mask.

(Prior Art) Normally, a color picture tube has a phosphor screen made of three-color phosphors on the inner surface of a spherical panel (■) constituting the front part of the envelope (υ), as shown in Figure 15. (2) is formed, and a shadow mask (0) is arranged inside the phosphor screen (2) at a predetermined distance from the phosphor screen (2), and has a spherical mask main body (with a large number of electron beam passage holes) whose peripheral portion is supported by a mask frame (3). It is set up. Thus, the three electron beams (9) emitted from the electron gun (8) arranged inside the neck ■ of the envelope ■ are deflected by the deflection device (10) placed outside the envelope ■. Then, the phosphor screen (3) passes through the electron beam passage hole of the shadow mask (Q).
It is configured to display a color screen by making the light incident on the screen.

By the way, the above-mentioned shadow mask (in the mask body of Q) is usually formed of a steel plate with a thickness of about 0.2 ann, and its peripheral part is supported by a mask frame (c) with a thickness of about 11111, and the mask The area occupied by the electron beam passage hole in the main body (a), that is, the beam transmittance, is 30% or less. Therefore, most of the electron beam (9) emitted from the electron gun (8) impinges on this shadow mask (2) and heats it. By this heating, the spherical shadow mask 0 is heated in the phosphor screen ■ direction and the tube axis (11
), and the electron beam (2) does not properly enter the fluorescent screen (2), causing deterioration in color purity and making it impossible to display a correct color image.

In order to prevent this, Japanese Patent Publication No. 44-3547 discloses that a bimetal piece (13) is attached to the mask frame (■), and the elastic support (14a) attached to this bimetal piece (13) is attached to the inside wall of the panel (■). The panel pin (
15) to prevent mislanding caused by thermal expansion of the shadow mask (2).

However, this bimetal system has the problem that the shadow mask support structure is complicated, and that assembly accuracy tends to vary due to the large number of parts, making it difficult to manufacture color picture tubes with consistent screen quality. Ta.

In order to solve this problem, as shown in Figure 6,
An elastic support (14a) having a different structure from the elastic support (14a)
14b) to the four corners of the mask frame 0 of the rectangular shadow mask 0 to support the shadow mask 0 has been developed. This elastic support (14b) has a dogleg-shaped movable part (14b) that is removably engaged with a fixed piece part (17) and a spring pin (15) attached to the mask frame (2) with the tube axis (11) direction as the longitudinal direction. 18) are bent and molded together to form a wedge-shaped outer shape, or
Alternatively, the fixed piece (17) and the movable piece (18) may be formed separately and fixed together at the wedge-shaped top.

The second elastic support (14b) is heated by the impact of the electron beam, and expands in the direction perpendicular to the tube axis (11) of the shadow mask 0, so that the fixing piece portion of the second elastic support (14b) is (17) is displaced a distance d in the same direction, the wedge-shaped top (19) moves a distance in the direction of the fluorescent screen (■), so based on the displacement of this elastic support (14b),
Mislanding, that is, color shift on the screen due to thermal expansion of the shadow mask (2) can be effectively corrected.

However, due to its structure, this elastic support (14b) has the problem that when an external impact is applied to the color picture tube, the relative positional relationship between the shadow mask 0 and the phosphor screen ■ changes easily, resulting in deterioration of screen quality. There is a point.

(Problems to be Solved by the Invention) As described above, the shadow mask has a fixed piece that is fixed to the mask frame with the tube axis direction as the longitudinal direction, and a dog-shaped movable piece that is detachably locked to the panel. When supported by a wedge-shaped elastic support with one piece, it is possible to effectively correct color shift on the screen due to thermal expansion of the shadow mask.
On the other hand, it is vulnerable to external shocks, and there is a problem that the relative positional relationship between the shadow mask and the phosphor screen changes, easily deteriorating the screen quality.

This invention was made in order to solve the above-mentioned conventional problem, and it is a color picture tube that supports a shadow mask with the wedge-shaped elastic support. The purpose is to create a stable structure.

[Structure of the invention]

(Means for Solving the Problem) A shadow mask, in which the peripheral part of the mask body is supported by a mask frame, is mounted on the inner surface of the panel, facing the fluorescent screen formed on the inner surface of the panel, and is detachably attached to the panel using an elastic support. In a color picture tube to be fixed, the elastic support is removably engaged with a fixing piece fixed to the mask frame and extending with the tube axis direction as the longitudinal direction, and the panel, and the tip end is attached to the fixing piece. It consists of a movable piece fixed to one end, and the thickness of the fixed piece is 1.5 times or more that of the movable piece.

(Function) When an elastic support is constructed by fixing two elastic pieces consisting of a fixed piece and a movable piece, deformation of the elastic support that occurs when receiving an external impact can be locally concentrated, and By making the thickness of the fixed piece at least 1.5 times the thickness of the movable piece, the effect of one local deformation can be increased, and a color picture tube that is resistant to external shocks can be obtained.

(Example) The present invention will be described below based on an example with reference to one drawing.

The overall configuration of the color picture tube is the same as that of a conventional color picture tube except for the support means for the shadow mask, so a description thereof will be omitted and the main parts will be explained below with reference to FIG. 1.

The shadow mask 0 is composed of a spherical mask body (A) with a substantially rectangular outer shape, in which a large number of electron beam passage holes are arranged in a predetermined relationship, and a mask frame 0 that supports the peripheral skirt portion. , the above mask frame 0
The mask body (A) is formed on the inner surface of the panel ■ by an elastic support (20) that is attached along the outside of the four corners of the panel ■ and removably engaged with a panel pin (15) provided on the inner wall of the panel ■. It is supported so as to face and be spaced apart from the phosphor screen (2).

Therefore, the elastic support body (20) is arranged in the tube axis direction (11
) is bent into a dogleg shape, consisting of a strip-shaped fixing piece (21) made of an elastic member fixed to the outside of the mask frame ■ in the longitudinal direction, and an elastic member detachably locked to the panel pin (15). The distal end of the movable piece (22) is connected to the fixed piece (21).
It is integrally fixed to one end of the phosphor screen (1) by means such as welding, and has a wedge-shaped outer shape. Therefore, this elastic support (20) has a plate thickness of, for example, 0.4 g.
For the + movable piece (22).

The fixed piece (21) is formed to have a thickness of about 0.6 to 1.2 nm, and has a thickness that is 1.5 times or more that of the movable piece (22).

By the way, the elastic support (20) configured as described above
Similar to the conventional elastic support shown in FIG. 6, the shadow mask 0 corrects the displacement due to thermal expansion of the shadow mask 0 heated by the impact of the electron beam.

That is, focusing on one electron beam passage hole (24) of the shadow mask 0, assuming that the shadow mask 0 heated by the electron beam impact is freely displaced, the electron beam passage hole (24) is aligned with the tube axis. It moves to a point (24a) far away from (11) in the direction orthogonal to it, but since the elastic support (20) has a wedge-shaped apex angle of angle α,
As shown by a point (24b), a part of the free displacement of the shadow mask 0 is converted in a direction to bring it closer to the phosphor screen (2). As a result, the mislanding caused by the thermal expansion of the shadow mask 0 is corrected, and a correct color image without color shift is displayed on the phosphor screen (2).

Moreover, when the elastic support body (20) is configured as described above,
The shadow mask (2) can be stably supported against external impact. FIG. 2 is a diagram for explaining the effect of the elastic support (20) on this external impact, in which (A) and (B) are conventional elastic supports formed in the same shape, and (C) The figure shows the elastic support (
20). In these figures, the mark Δ indicates the fixed part with the mask frame ■, and assuming that the external impact is transmitted to the elastic support via the panel pin (15),
The impact force is indicated by an arrow (26). The impact force actually applied to a color picture tube is not constant in magnitude or direction, but the above case can be representative when considering the deformation of an elastic support.

In Figures (A) or C), if the thickness of the movable piece (or movable piece part) is the same, then the fixed piece part (17) and the movable piece part (18) shown in Figure (A) can be folded. In a conventional elastic support of constant plate thickness formed by bending, the arrow (
The deformations shown in (a) to (f) occur, and the magnitude is (d)
〉(b)〉(a)〉(c)〉(e)〉(f) The amount of deformation in (b) is particularly large, and the entire elastic support is deformed greatly. On the other hand, in the case of the elastic support shown in FIG. A)〉(E)〉〉(C), especially compared to the elastic support shown in Figure (A), the amount of deformation of (E) and (E) becomes larger, and the amount of deflection of the branch body becomes larger. becomes smaller. Furthermore, in the elastic support (20) of this embodiment in which the fixed piece (21) shown in Figure (C) is thicker than the movable piece (22) and is fixed together, (d) 〉(b)〉(e)Misaki(he)〉(
C), the deformation of the fixed portion (29) is very small, and the amount of deformation in (E) and (F) is larger than that of the elastic support shown in (B).

In other words, when a fixed piece and a movable piece are fixed to form an elastic support, the angle between the fixed piece and the movable piece changes greatly, and the overall amount of deflection becomes small. If the plate thickness is thicker than that of the movable piece, the change in the angle between the fixed piece and the movable piece will be even larger, and the overall amount of deflection can be further reduced. It can be an elastic support.

Normally, shock resistance tests for color picture tubes are performed using acceleration tests or vibration tests, taking into account vibrations applied during transportation, shocks applied during receiver assembly, etc. 6 Table 1
In this example, the thickness of the movable piece (22) is 0.4 m, and the thickness of the fixed piece (22) is 0.4 m.
An elastic support (2) with a thickness of 0.5 to 1.8 mm
0) shows the results of an acceleration test of a color picture tube supporting a shadow mask 0. The test was evaluated using the commonly used visual evaluation of white uniformity.

Table 1 In this table 1, ◎ is extremely good, 0 is practical, Δ
Although it is practical, it shows that it is close to the limit, and from this test result, the plate thickness of the fixed piece (21) is changed to that of the movable piece (22).
It can be seen that if the thickness is 1.5 times or more than the plate thickness, a color picture tube that is stable against external shocks can be obtained.

Note that even if the fixed piece (21) has a plate thickness of 1.8 m+ or more with respect to the movable piece (22) with a plate thickness of 0.4 mm, the external Wr
Stability against attacks hardly changes. Furthermore, the above test was conducted using a movable piece (22) with a plate thickness of 0.4 m.

Even if the thickness of this movable piece (22) is 0.4 m or more,
If the thickness of the fixing piece (21) is correspondingly increased, a color picture tube that is also stable against external shocks can be obtained.

However, as the thickness of the movable piece (22) increases, it becomes difficult to attach and detach the shadow mask 0 when forming the phosphor screen, and furthermore, due to the excessive load applied to the shadow mask 0, Conversely, if the thickness of the movable piece (22) is made thinner, shadow mask 0 will be easier to attach and detach, and shadow mask 0 will not be deformed, but as the spring strength decreases, , the stability against external impact decreases.

As described above, if the elastic support body supporting the shadow mask 0 is composed of the fixed piece (21) and the movable piece (22) and they are fixed together to form a wedge shape, the shadow mask 0 can be shadowed during operation of the color picture tube. Part of the thermal expansion displacement in the direction orthogonal to the tube axis (11) of mask 0 is converted into displacement in the direction of the fluorescent screen ■, thereby effectively correcting the color shift on the screen caused by the thermal expansion of the shadow mask ■. Moreover, by reducing the amount of deflection of the entire elastic support body against external impact, and in particular by making the thickness of the fixed piece (21) at least 1.5 times the thickness of the movable piece (22), The color picture tube can be made stable against external g959.

Next, other embodiments will be described.

The elastic support (20) shown in FIG. 3 has a movable piece (22) provided with a reinforcing portion (30). The elastic support (20) absorbs the stress applied to the elastic support due to an external impact from a portion of the movable piece (22) other than the portion where the reinforcing portion (30) is formed.
In particular, it can be concentrated in the part where it is fixed to the fixing piece (21), and it can be made into a necessary elastic support that can easily attach and detach the shadow mask when forming the phosphor screen.

Note that this reinforcing portion (30) is a dogleg-shaped movable piece (22).
A similar effect can be obtained by providing it only on one side.

The elastic support (20) shown in Fig. 4 is an example in which a fixed piece (21) is provided with a recessed hole (31) for welding to the mask frame of the shadow mask. It is attached to the mask frame, but the fixing piece (21
) When the thickness of the plate increases, especially in the case of laser welding, a high output laser welding device is required.

Furthermore, when performing resistance welding, it is necessary to increase the pressure on the welding electrode, which not only shortens the life of the electrode, but also increases the size of the electrode, making it difficult to perform the welding work. However, if the recessed hole (31) is provided as described above and the plate thickness is locally thinned within a range that does not affect the spring strength of the fixing piece (21), the required welding can be easily performed.

Note that the same effect can be obtained even if a groove is formed instead of such a recessed hole (31).

〔Effect of the invention〕

In a color picture tube, a shadow mask, in which the peripheral part of the mask body is supported by a mask frame inside the phosphor screen formed on the inner surface of the panel, is removably fixed to the panel by an elastic support. The body is made up of a fixed piece that is fixed to the mask frame and extends with the tube axis direction as the longitudinal direction, and a movable piece that is removably engaged with the panel and whose tip is fixed to one end of the fixed piece. If the thickness of the fixed piece is at least 1.5 times that of the movable piece, the color of the screen that is caused by thermal expansion of the shadow mask due to the impact of the electron beam during operation of the color picture tube can be reduced. It is possible to provide a stable color picture tube that can effectively correct misalignment and that does not deteriorate the screen quality against vibrations and shocks applied during transportation of the color picture tube or when assembling the picture receiver.

[Brief explanation of drawings]

Figures 1 to 4 are detailed explanatory diagrams of this invention.
The figure is a cutaway sectional view showing the main structure of a color picture tube according to an embodiment, and Figures 2 (A) to 2C are views showing the effect of the elastic support in comparison with the effect of a conventional elastic support. , FIG. 3 is a diagram of an elastic support in another embodiment, FIG. 4 is a diagram of an elastic support in another embodiment, and FIG. 5 is a sectional view showing the overall structure of a conventional color picture tube. , FIG. 6 is a cutaway sectional view showing the main structure of a conventional color picture tube having a wedge-shaped elastic support. ■... Panel ■... Fluorescent screen)... Mask body 0... Mask frame 0... Shadow mask (11)... Tube shaft (20)... Elastic support (21) ...Fixed piece (22)...Movable piece
(30)...Reinforcement part (31)...Concave hole agent Patent attorney Inoue-Male No. 1 Figure 41!1 ′□X @21!1 @Figure 6

Claims (3)

[Claims] (1) an envelope having a panel on the front surface; a shadow mask in which the peripheral part of the mask body facing the phosphor screen formed on the inner surface of the panel is supported by a mask frame; an elastic support member that is removably engaged with a panel to support the shadow mask; a fixed piece that is fixed to the mask frame and extends in the tube axis direction; It consists of a movable piece that is removably engaged with the panel and whose tip end is fixed to one end of the fixed piece, and the plate thickness of the fixed piece is 1.5 times or more that of the movable piece. A color picture tube characterized by: (2) The color picture tube according to claim 1, wherein the movable piece of the elastic support has a reinforcing portion except in the vicinity of the portion where it is fixed to the fixed piece. (3) The color picture tube according to claim 1, wherein the fixing piece of the elastic support has a thin portion for welding to the mask frame.