JPH02306524A - Shadow mask body structure for color image-receiving tube - Google Patents

Abstract

PURPOSE:To avoid chromatic misconvergence due to thermal expansion of a shadow mask by using a high expansion material to a frame which supports and reinforces the shadow mask, and a low expansion material to a spring for fixing the frame to a panel, and converting the expansion difference due to temp. into motion of a moving point at the tip of a spring. CONSTITUTION:A spring 1 to fix a frame 2 for supporting and reinforcing a shadow mask 10 to a panel 8 is made from a low expansion material such as Invar material, and the spring part is connected with one edge of an L-shaped supporting part, which is secured at its two ends to the frame 2 made of a high expansion material such as ferric material by means of welding. Accordingly the L-shaped supporting part widens to <ABC when the frame 2 expands with bombardment of electron beam to cause increase in the distance A-C, where A, C are securement points of the spring 1 with frame 2, B is the bent point of the L-shaped supporting part, and D is the point of motion of the spring 1. This changes the angle of the spring part connected with the supporting part to cause downward movement of the point of motion D.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a shadow mask structure for a color picture tube.

[Conventional technology]

Conventionally, this type of shadow mask structure has a shadow mask structure with a large number of microholes arranged in order to select and irradiate the three color phosphors formed on the inner surface of the picture tube panel with the corresponding electron beams. I am using it.

As shown in FIGS. 5(a) and 5(b), the shadow mask structure includes a shadow mask 10 in which a large number of microholes for color selection are arranged, and the shadow mask 10 fixed by a method such as welding. Frame 2 to increase strength,
A spring is used to fix the mask frame assembly, which is a combination of the shadow mask 10 and the frame 2, to the panel 8 on which a fluorescent film is formed while maintaining a constant distance, and the inner surface of the panel 8 is used to prevent thermal expansion of the shadow mask 10. The bimetal 6 has the function of adjusting the distance between the surface of the shadow mask 10 and the surface of the shadow mask 10 to appropriately correct the relationship between the electron beams irradiated onto the phosphor.

Alternatively, as shown in FIGS. 6(a) and 6(b), instead of the bimetal, a material obtained by welding a high-expansion material 5 and a low-expansion material 4, which are generally called ordinary joint metal, butt against each other, may be used. It has the same correction function as .

FIG. 5(a) shows a method of providing a position adjustment function for correcting color shift due to thermal expansion of the cover.

Bimetal 6 such as that shown in Figures 6 (a) and (b)
Generally, parts made of a material called ordinary bonding metal are used. These parts have the disadvantage that they are expensive due to special manufacturing methods, increasing the manufacturing cost of the shadow mask structure.

SUMMARY OF THE INVENTION An object of the present invention is to provide a shadow mask structure for a color picture tube that is inexpensive to manufacture and capable of correcting color shift caused by thermal expansion of the shadow mask.

[Means to solve the problem]

The present invention provides a panel, a fluorescent film formed on the inner surface of the panel, a shadow mask arranged at regular intervals on the inner surface of the panel, a frame for supporting and reinforcing the shadow mask, and a frame fixed to the panel. In a shadow mask structure for a color picture tube having a spring for
A high expansion material is used for the frame, and a low expansion material is used for the spring.

[Example] Next, an example of the present invention will be described with reference to the drawings.

1(a) and 1(b) are a front view and a sectional view of a first embodiment of the present invention, and FIG. 2 is a diagram of the operating principle of the first embodiment of the present invention.

In the first embodiment, as shown in FIGS. 1(a) and 1(b), the spring 1 is made of a low-expansion material such as Invar material, and the spring portion is attached to one side of an L-shaped support part. The L-shaped support part i is fixed at both ends to a frame 2 made of a high expansion material such as iron using a method such as welding.

Next, the operation will be explained using FIG. 2. Points A and 0 shown in FIG. 2 represent the fixing points of the spring and frame of the first embodiment, point B represents the bending point of the L-shaped support, and point D represents the operating point of the spring.

The shadow mass 10 and the frame 2 generate heat and expand due to the collision with the electron beam. Due to the expansion of frame 2, A
- As the distance between points C increases, the L-shaped support expands <ABC. As a result, the spring connected to one side of the L-shaped support also changes its angle, moving the operating point downward. The amount of movement in xmm is the thermal expansion coefficient of the frame material of 2. The thermal expansion coefficient of the spring material is β, <ABC is θ, E
When D is L mm and B=B, if there is a temperature change of 6°C, it can be expressed as θ θ 1 □) (1).

To give a specific example, L = 4Qmm, a = 12 x 10-', β =
I
Then, if X = 0.038 mm and θ = 150°, then x = 0.082 mm.

As can be seen from the measurement example, θ
is determined, and the color shift can be corrected.

The above description and explanatory drawings are examples of the first embodiment of the present description, and the shape of the low expansion material spring, etc. is not limited to the above configuration.

3(a) and 3(6) are a front view and a sectional view of the second embodiment of the present invention, and FIG. 4 is a diagram of the operating principle of the second embodiment of the present invention.

In the second embodiment, as shown in 5E(a) and (c),
The spring 1 is made of a low expansion material such as Invar material, and the frame 2 is made of a high expansion material such as iron. The frame 2 is provided with a slit as shown by the thick line, and the two fixed ends cut into rod shapes are positioned symmetrically with respect to each other. Spring 1 is attached to both free ends of these two rods.
be welded together to bind them together.

Next, the principle of operation will be explained with reference to FIG. The rod-shaped fixed ends A and B of the frame become A' and B due to thermal expansion.
' respectively. The free ends of the rods also try to extend in the radial direction, but because the distance between the sigma are restricted, they sag inward as shown in FIG. At this time, since the two rods are installed in point-symmetrical positions, the position C'D' of the free end after thermal expansion moves in the rotational direction around the intermediate point 0. As a result, the spring attached to the tip of the rod-shaped portion also rotates around the zero point, and the operating point E moves, making it possible to correct color shift due to thermal expansion of the shadow mask.

In this example, since the spring does not have a bending point,
There is an advantage that the strength of the spring can be made stronger than that of the first embodiment.

〔Effect of the invention〕

As explained above, the present invention uses a high-expansion material spring and a low-expansion material in the frame and fixes them at two or more points, thereby converting the difference in expansion due to temperature into movement of the operating point of the spring tip. This has the effect of correcting color shift caused by thermal expansion of the shadow mask of a color picture tube.

[Brief explanation of drawings]

1(a) and 1(b) are a front view and a sectional view of the first embodiment of the present invention, FIG. 2 is a diagram of the operating principle of the first embodiment of the present invention, and FIG. 3(a), (b) is a front view and a sectional view of the embodiment of the present invention shown in FIG. 2, FIG. 4 is a diagram of the operating principle of the second embodiment of the present invention, and FIGS. A front view and a sectional view of an example of a shadow mask structure for a color picture tube. FIGS. 6(a) and 6(b) are a front view and a sectional view of another example of a conventional shadow mask structure for a color picture tube. 1...Low expansion material spring, 2...Frame, 3...Welding point, 4...Low expansion material, 5...High Expansion, (α) Mo6 27L-m (b) Fig.

Claims (1)

[Claims] A panel, a fluorescent film formed on the inner surface of the panel, a shadow mask arranged at regular intervals on the inner surface of the panel, a frame for supporting and reinforcing the shadow mask, and a frame for fixing the frame to the panel. 1. A shadow mask structure for a color picture tube comprising a spring, wherein the frame is made of a high expansion material, and the spring is made of a low expansion material.