JPH0744012B2 - Color picture tube - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bimetal type in which one side edge having a welding line along the longitudinal direction as a boundary is made of a metal having a high expansion coefficient and the other side edge is made of a metal having a low expansion coefficient. The present invention relates to a color picture tube in which a shadow mask and a mask frame mounted with the leaf spring are elastically supported in a face panel by using a leaf spring.

2. Description of the Related Art In a shadow mask type color picture tube, in order to elastically support a mask frame on which a shadow mask is mounted in a face panel, three or four leaf springs are provided between the mask frame and the face panel. It is common practice to sprinkle between them. In this case, the fixing region that is one end edge in the longitudinal direction of each leaf spring is fixed to the outer surface of the side wall of the mask frame by welding,
The pin protruding from the inner surface of the side wall of the face panel is fitted into the hole provided at the tip of the remaining movable region.

By the way, the shadow mask mounted on the mask frame is subject to electron beam bombardment during the operation of the tube to become a high temperature and thermally expands. As a result, the position occupied by the aperture in the shadow mask, especially in the peripheral portion, moves, and it becomes difficult for the electron beam that has passed through this aperture to faithfully excite the predetermined phosphor dots or phosphor strips to emit light, causing a so-called color shift. . Therefore, a bimetal type leaf spring is used to slightly move the shadow mask whose temperature has risen to the phosphor screen side.In a color picture tube configured in this way, the shadow mask heat It is possible to almost completely prevent the occurrence of color shift due to expansion.

Referring to FIGS. 3 and 4 showing a conventional bimetal type leaf spring, the leaf spring 1 has a fixing region 4 welded to an outer surface of a side wall of a mask frame 3 on which a shadow mask 2 is mounted on one end edge in the longitudinal direction. A hole 6 is provided at the tip of the remaining movable area 5. The hole 6 fits and engages the tip of the pin protruding from the inner surface of the side wall of the face panel (not shown), and the one side edge 8 with the weld line 7 along the longitudinal direction as a boundary is made of a metal having a high expansion coefficient. The other side edge 9 is made of a low expansion coefficient metal. And this leaf spring 1
As the temperature rises, it distorts into the shape shown by the broken line in FIG. 4, but since the hole 6 engages with the pin, it rotates about this pin as a rotation support shaft and is fixed in the fixing region 4. The mask frame 3 and the shadow mask 2 that are present are pushed up toward the phosphor screen surface side. 4a indicates a welding point.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention By the way, in a small-sized color picture tube, the amount of thermal strain required for the bimetal type leaf spring as described above is extremely small. However, even for a small color picture tube, a short leaf spring cannot be used to elastically support the mask frame.
Therefore, it is conceivable to reduce the difference in thermal expansion coefficient between the two metals or increase the spring width. However, considering the weldability and spring constant, it is extremely difficult to select two metals in an appropriate combination. It becomes difficult.

It is most preferable to use 18Cr-8Ni stainless steel having a good spring property as the high expansion coefficient metal and to widen the width of the high expansion coefficient metal on the side of the welding point where the bending stress becomes large.

Therefore, it is an object of the present invention that a relatively long leaf spring can be used and the desired heat can be obtained even when the relative materials of the high expansion coefficient metal and the low expansion coefficient metal are the same as in the conventional case. It is an object of the present invention to provide a color picture tube having a mask support structure capable of obtaining distortion characteristics and thereby biasing the shadow mask toward the phosphor screen surface by an appropriate amount.

Means for Solving the Problems A color picture tube according to the present invention is a color picture tube in which a mask frame is supported on a face panel by a leaf spring made of bimetal in which a high expansion coefficient metal and a low expansion coefficient metal are joined by welding. The leaf spring includes a fixed region fixed to the outer surface of the side wall of the mask frame, and a movable region adjacent to the fixed region and fixed to the side wall of the face panel. In order that both ends of the welding line joining the low expansion coefficient metal intersect two side edges along the longitudinal direction of the movable region,
The welding line is located only in the movable area.

Operation With this configuration, the thermal working length of the leaf spring can be set regardless of the mechanical working length only by selecting the length (tilt angle) of the welding line. In other words, the leaf spring can be set. The length of the shadow mask can be made constant, and the shadow mask can be biased to the phosphor screen surface side by an appropriate amount with a leaf spring having a predetermined thermal strain characteristic.

EXAMPLES Next, the present invention will be described with reference to the illustrated examples.

As shown in FIG. 1, a bimetal type leaf spring 10
Is made by joining a high expansion coefficient metal and a low expansion coefficient metal by welding, and one end is welded to the outer surface of the side wall of the mask frame 3 to which the shadow mask 2 is attached at a welding point 11. As a result, the leaf spring 10 is formed with a fixed region 12 that is substantially immovable from the one end edge to the welding point 11. Leaf spring 10 has a fixed area
A movable region 13 is formed adjacent to 12. Movable area 13
A hole 14 is provided at the tip of the leaf spring 10, and the other end of the leaf spring 10 is fixed to the face panel by inserting the hole into a pin protruding from the inner surface of the side wall of the face panel. And high expansion coefficient metal 15 and low expansion coefficient metal 16
Both ends of the welding line 17 with the movable area 13 of the leaf spring 10
The weld line 17 is located only in the movable region 13 so as to intersect the two side edges along the longitudinal direction of the. The thermally actuated length 18 of the leaf spring 10 is the length from one end of the weld line 17 to the center of the hole 14, from the weld point 11 to the leaf spring.
Mechanical working length up to the center of 10 holes 14 less than 19.

FIG. 2 shows another example of the bimetal type leaf spring 10, in which the weld line 17 between the high expansion coefficient metal 15 and the low expansion coefficient metal 16 is shorter than that in FIG. The thermally actuated length 19 of the leaf spring 10 is the same as that in FIG. 1, but the thermally actuated length 18 is shorter than that in FIG.

In this way, by using leaf springs of the same size and changing the length of the welding line 17 arbitrarily, both metal 1
It is possible to obtain a bimetal type leaf spring having a desired thermal strain characteristic without changing the combination of the materials of 5, 16 and thereby completely prevent the occurrence of color misregistration due to thermal expansion of the shadow mask.

EFFECTS OF THE INVENTION As described above, according to the present invention, by merely changing the length of the welding line of two metals of the bimetal type leaf spring, it is possible to give this spring an arbitrary thermal strain characteristic, and to provide a shadow mask which is thermally expanded. The leaf spring can be moved according to the amount of thermal expansion, and a relatively long leaf spring can be used. Therefore, the mechanical operating length is not shortened and there is no restriction on the selection of the material of the two metals. Excellent effect when applied to color picture tubes. In addition, the present invention is 14
It is possible to share the leaf spring with color picture tubes of various sizes such as inch, 19 inch, 25 inch, 33 inch, and for various purposes such as TV, computer display, etc. Since a leaf spring having a constant outer shape can be used, there is also an effect such that the manufacturing efficiency of the leaf spring can be improved by sharing the manufacturing jig and the packing material.

[Brief description of drawings]

FIG. 1 is a side view of a main part of a color picture tube embodying the present invention, FIG. 2 is a side view of a leaf spring of the same picture tube, and FIG. 3 is a partial perspective view of a conventional color picture tube. The figure is a side view of the leaf spring of the same color picture tube. 2 ... Shadow mask, 3 ... Mask frame, 10 ...
Leaf spring, 12 ... fixed area, 13 ... movable area,
15 …… High expansion coefficient metal, 16 …… Low expansion coefficient metal, 17 …… Welding line.

Claims (1)

[Claims] 1. A color picture tube in which a mask frame is supported on a face panel by a leaf spring made of bimetal in which a high-expansion metal and a low-expansion metal are joined by welding. In the color picture tube, the leaf spring is a sidewall of the mask frame. A fixed area fixed to the outer surface and a movable area adjacent to the fixed area and fixed to the side wall of the face panel, which is a welding line for joining the high expansion coefficient metal and the low expansion coefficient metal. A color picture tube characterized in that the welding line is located only in the movable area so that both ends intersect two side edges along the longitudinal direction of the movable area.