JP2000353476A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the amplitude of a resonance with an external vibration by increasing the rigidity of both end parts of a shadow mask, by forming both ends of the cylindrical shadow mask corresponding to lateral ends of a screen plane into nearly circular arc shapes. SOLUTION: A shadow mask 11 is shaped into a cylindrical surface by being welded at welding points 14 to cylindrical end faces of a pair of parallel flat plates on vertical ends of a mask frame 12. Lateral ends of the pair of parallel flat plates corresponding to the vertical ends of the mask frame 12 are formed into nearly circular arc-shaped parts 13 while both ends of the shadow mask 11 corresponding to the lateral ends are formed into nearly circular arc-shaped parts 15 similar to the nearly circular arc-shaped parts 13 of the mask frame 12. This increases the rigidity of the lateral ends of the shadow mask 11 and correspondingly decreases a resonance amplitude, and therefore, a resonance with an external vibration can be prevented to the extent that color slippage becomes insignificant without fixing the lateral ends of the shadow mask 11 or applying vibration damping bodies on the lateral ends of the shadow mask 11, and the color shift becomes imperceptible if it occurs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube having a shadow mask having a vibration damping function.

[0002]

2. Description of the Related Art A color CRT widely used at present is a so-called shadow mask color CRT. As is well known, a shadow mask generally has a large number of circular or rectangular electron beam passage holes in an iron or iron-nickel alloy thin plate. The shadow mask having the through holes is called a slot type shadow mask. Conventionally, both dot-type shadow masks and slot-type shadow masks have often been press-molded into spherical shapes. This is because a spherical shadow mask has a high rigidity and can hold its shape by itself, so that a special shape holding mechanism is not required.

However, recently, the screen of a color cathode ray tube is formed to be a part of a cylindrical surface close to a plane from a conventional spherical surface (hereinafter, "a part of the cylindrical surface" is abbreviated as a "cylindrical surface") or a complete flat surface, so that the screen is more easily viewable. Tend to try. For this purpose, the shape of the shadow mask must be changed from a spherical surface to a cylindrical surface or a flat surface.However, unlike a spherical shadow mask, the shadow mask of a cylindrical surface or a flat surface has a low rigidity and cannot hold its shape by itself. Cost. As one example, there is an attempt to apply a tension to a cylindrical shadow mask and hold the shadow mask on a mask frame as disclosed in JP-A-8-77936.

If the shadow mask is not a cylindrical surface but a flat surface, the rigidity of the flat shadow mask is lower than that of the cylindrical shadow mask, so that the mechanism for holding the shadow mask becomes extremely complicated. In addition, focus around the screen,
Since the convergence is greatly deteriorated, it is necessary to greatly improve the deflection yoke, the electronic lens, the focus circuit, and the like in order to solve the problem. Therefore, a flat shadow mask is not always advantageous compared to a cylindrical shadow mask, and a cylindrical shadow mask is often more practical because of its better balance between cost and performance.

[0005]

Since the current shadow mask has a very small thickness and a low rigidity of the material itself in order to increase the resolution, a shadow mask having a cylindrical surface (hereinafter referred to as a cylindrical shadow mask) is used. ) Tension can be applied in the direction along the axis of the cylindrical surface (vertical direction of the color CRT screen, hereinafter referred to as the vertical direction), but it can be applied in a direction perpendicular to it (horizontal direction of the color CRT screen; ), It is impossible to apply tension and it is difficult to even fix the left and right ends. Forcibly fixing the left and right ends causes wrinkles in the shadow mask, causing color misregistration and not practical.

However, if the left and right ends of the cylindrical shadow mask are completely free ends, the shadow mask resonates with external vibration from a speaker or the like to produce a color shift even when tension is applied in the vertical direction, so that the shadow mask is also practically used. do not become.

As means for preventing the above-mentioned resonance of the cylindrical shadow mask, JP-A-8-77936, JP-A-9-284767 and JP-A-9-274868 disclose the right and left ends of the cylindrical shadow mask. Discloses a structure in which a vibration attenuator is brought into contact.

However, in the structure disclosed in the above publication, it is necessary to fabricate a vibration damping body having a complicated shape, and to fix it to a mask frame with high precision, and abut against a shadow mask. It requires a considerable increase in cost and a weight increase is inevitable.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to provide a high-quality color cathode-ray tube having a cylindrical shadow mask capable of reducing resonance to a practical level with an inexpensive and lightweight structure.

[0010]

In order to achieve the above object, the present invention relates to a color cathode ray tube having a cylindrical shadow mask, wherein both ends corresponding to the left and right edges of the screen of the cylindrical shadow mask are formed into a substantially arc shape. By doing
By increasing the rigidity of both ends of the shadow mask and reducing the resonance amplitude with external vibration, color misregistration can be achieved without fixing the left and right ends of the shadow mask or abutting the vibration attenuator on the left and right ends of the shadow mask. It is characterized in that resonance is reduced to an extent that there is no problem.

According to a first aspect of the present invention, there is provided a mask frame formed by connecting and holding a pair of parallel flat plates corresponding to upper and lower ends of a screen of a color CRT and a pair of parallel flat plates corresponding to left and right ends of the screen. A shadow mask is fixed by applying tension between a pair of parallel flat plates corresponding to upper and lower ends of the screen of the mask frame, and the shape of the shadow mask is a cylindrical surface of an axis parallel to the vertical direction of the screen of the color cathode ray tube. The left and right ends of a pair of parallel flat plates corresponding to the upper and lower ends of the screen of the mask frame form a substantially arcuate portion, and both ends corresponding to the left and right ends of the screen of the shadow mask are the mask frame. Characterized in that it is formed into a substantially circular arc shape similar to the substantially circular arc-shaped portion.

According to a second aspect of the present invention, in the shadow mask, both ends of the shadow mask corresponding to the right and left ends of the screen are formed into a pair of substantially arc-shaped portions corresponding to upper and lower ends of the screen of the mask frame. It is characterized in that the parallel flat plate is fixed to a substantially arc-shaped portion at the left and right ends.

According to a third aspect of the present invention, a bent portion is provided at a tip of a substantially arc-shaped portion at both ends corresponding to the left and right ends of the screen of the shadow mask. .

According to a fourth aspect of the present invention, the bent portion of the shadow mask is a plurality of bent portions two or more times.

A fifth aspect of the present invention is characterized in that the shadow mask has embossed portions at both ends corresponding to the right and left ends of the screen, which are formed in a substantially circular arc shape.

[0016]

With the above configuration, even when the cylindrical shadow mask is tensioned only in the vertical direction and fixed by welding to the mask frame, the rigidity of the left and right ends of the shadow mask is high and the resonance amplitude is low. The resonance with external vibration can be reduced to the extent that there is no problem with color deviation without fixing the left and right ends of the camera or touching the vibration attenuating body to the left and right ends of the shadow mask, causing perceived color deviation do not do. Also, by welding and fixing the roughly circular arc-shaped portions at both left and right ends of the shadow mask to the roughly circular arc-shaped portions at both right and left ends of the mask frame, the rigidity of both ends of the shadow mask is made higher, the resonance amplitude is made lower, and the color is reduced. The displacement can be further reduced.

Further, in the above-described configuration, only a slight design change is made to the existing mask frame or shadow mask, so that weight increase and cost increase are extremely small.

[0018]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view showing the structure of a shadow mask structure 10 mounted on a color cathode ray tube according to a first embodiment of the present invention before assembly. FIG. 2 is a perspective view showing the shadow mask structure 10 after assembly. Direction front view and XX 'sectional view,
1 is a shadow mask, 12 is a mask frame, 13 is a substantially arc-shaped portion at the left and right ends of the mask frame 12, 14 is a welding point between the shadow mask 11 and the mask frame 12, and 15 is a substantially arc at the left and right ends of the shadow mask 11. It is a forming part. The X direction indicates the horizontal direction of the screen of the color CRT, and the Y direction indicates the vertical direction of the screen of the color CRT. The screen of the color CRT is located above the perspective view. The material of the shadow mask 11 is an Invar alloy (36% nickel-iron alloy), and the material of the mask frame 12 is 13% chrome stainless steel.

As is well known, the shadow mask 11 is welded to the cylindrical end surfaces of a pair of parallel flat plates at the upper and lower ends of the mask frame 12 at the welding point 14 at the time of assembling to form a cylindrical surface. However, in the present embodiment, the mask frame 1
The left and right ends of a pair of parallel flat plates corresponding to the upper and lower ends of the screen 2 form a substantially arc-shaped portion 13, and both ends corresponding to the left and right ends of the screen of the shadow mask 11 are similar to the roughly arc-shaped portion 13 of the mask frame. Since the left and right ends of the shadow mask 11 are formed to have a higher rigidity and a correspondingly lower resonance amplitude as compared with a simple straight line as in the related art, since they are formed into a substantially circular arc-shaped portion 15. Even if the left and right ends of the shadow mask 11 are not fixed or the vibration attenuator is not brought into contact with the left and right ends of the shadow mask 11, resonance with external vibration can be prevented to the extent that color shift does not pose a problem. No color shift occurs. Both ends corresponding to the left and right edges of the screen of the shadow mask 11 are substantially arc-shaped portions 1 of the mask frame.
It is possible to form the substantially circular arc-shaped portion 15 similar to 3 before and after the shadow mask 11 is welded to the mask frame 12 at the welding point 14, but the shadow mask 11 is welded to the mask frame 12. If the left and right ends of the shadow mask 11 are formed into a substantially arc-shaped portion 15 before the shadow mask 11 is welded to the mask frame 12, misalignment does not easily occur when the shadow mask 11 is fitted to the mask frame 12. Further, since only the upper and lower ends of the screen are welded and the left and right ends are free ends, wrinkles do not occur on the shadow mask 11 as when the left and right ends are also fixed. Further, the invention of this embodiment is realized by small-scale design changes of the shadow mask 11 and the mask frame 12, and does not require special parts and does not require high processing accuracy, so that the weight and cost of the shadow mask structure 10 are increased. Is slight.

FIG. 3 is a perspective view showing a structure of a shadow mask structure 20 mounted on a color cathode ray tube according to a second embodiment of the present invention before assembling. FIG. 4 is a perspective view showing the shadow mask structure 20 after assembling. FIG. 10 is a front view in the direction of arrow A and a cross-sectional view taken along line XX ′.
Denotes a substantially circular arc-shaped portion at the left and right ends of the mask frame 22, 24 denotes a welding point between the shadow mask 21 and the mask frame 22, and 25 denotes a substantially circular arc-shaped portion at the left and right ends of the shadow mask 21.

According to this embodiment, the substantially arc-shaped portions 25 at the left and right ends of the shadow mask 21 which are not welded and fixed in the first embodiment are also replaced by the substantially arc-shaped portions 23 at the left and right ends of the mask frame 22. By welding and fixing to
The rigidity of both ends of the shadow mask 21 can be made higher than in the first embodiment, and the resonance amplitude can be reduced to further reduce the color shift.

FIG. 5 is a perspective view showing the structure of a shadow mask structure 30 mounted on a color cathode ray tube according to a third embodiment of the present invention before assembling. FIG. 6 is a perspective view showing the shadow mask structure 30 after assembling. FIG. 3 is a front view in a direction A and a cross-sectional view along the line XX ′.
Is a mask frame, 33 is a substantially arc-shaped portion at the left and right ends of the mask frame 32, 34 is a welding point between the shadow mask 31 and the mask frame 32, 35 is a roughly arc-shaped portion at the left and right ends of the shadow mask 31, and 36 is This is a bent portion (twice the number of times of bending) provided at the end of the substantially arc-shaped portion 35 at both ends corresponding to the left and right ends of the screen of the shadow mask 31.

According to this embodiment, since the bent portions 36 are provided at the ends of the substantially circular arc-formed portions 35 at both ends corresponding to the left and right ends of the screen of the shadow mask 31, the left and right rough circles of the shadow mask 31 are provided. The arc-shaped portion 35 has higher rigidity as compared with the first embodiment, and therefore the resonance amplitude of the shadow mask 31 is lower. For this reason, the color shift due to the resonance of the shadow mask 31 can be more reliably prevented. It should be noted that as the number of times the bending portion 36 is bent is as large as possible, the rigidity of the substantially arc-shaped portion 35 increases, and the effect of reducing the resonance amplitude of the shadow mask 31 increases. In this embodiment, as in the second embodiment, it is of course possible to weld and fix the substantially arc-shaped portions 35 at the left and right ends of the shadow mask 31 to the substantially arc-shaped portions 33 at the left and right ends of the mask frame 32, as in the second embodiment. This further increases the effect of reducing the resonance amplitude of the shadow mask 31.

FIG. 7 is a perspective view showing a structure of a shadow mask structure 40 mounted on a color CRT according to a fourth embodiment of the present invention before assembling. FIG. 8 is a perspective view showing the shadow mask structure 40 after assembling. FIG. 4 is a front view in the direction A and a cross-sectional view along the line XX ′,
Is a mask frame, 43 is a substantially arc-shaped portion at the left and right ends of the mask frame 42, 44 is a welding point between the shadow mask 41 and the mask frame 42, 45 is a roughly arc-shaped portion at the left and right ends of the shadow mask 41, 46 is A plurality of embosses are provided on the substantially arc-shaped portion 45 at the left and right ends of the shadow mask 41.

According to this embodiment, since the embossments 46 are provided in the substantially arc-shaped portions 45 at both ends corresponding to the left and right ends of the screen of the shadow mask 41, the shadow mask 41 is provided.
The substantially arc-shaped portions 45 at both left and right sides of the shadow mask 41 have higher rigidity as compared with the first embodiment, so that the resonance amplitude of the shadow mask 41 is lower. For this reason, the color shift due to the resonance of the shadow mask 41 is more reliably prevented. In this embodiment, as in the second embodiment, the substantially circular arc-shaped portions 45 at the left and right ends of the shadow mask 41 are also provided with the mask frame 42.
It is, of course, possible to weld and fix to the substantially arc-shaped portions 43 at the left and right ends, thereby further reducing the shadow mask 4.
1 is more effective in reducing the resonance amplitude.

[0026]

As described above, according to the present invention, it is possible to provide a high-quality color cathode-ray tube in which the vibration of a cylindrical shadow mask to which a tension is applied in the vertical direction of the screen is reduced with a low-cost and lightweight structure. it can.

[Brief description of the drawings]

FIG. 1 is a perspective view before assembling a shadow mask structure mounted on a first embodiment of a color cathode ray tube of the present invention.

FIG. 2 is a perspective view, a front view, and a cross-sectional view after assembling a shadow mask structure mounted on the first embodiment of the color cathode ray tube of the present invention.

FIG. 3 is a perspective view before assembling a shadow mask structure mounted on a color cathode ray tube according to a second embodiment of the present invention;

FIG. 4 is a perspective view, a front view, and a cross-sectional view of a shadow mask assembly mounted on a color cathode ray tube according to a second embodiment of the present invention after assembly.

FIG. 5 is a perspective view before assembling a shadow mask structure mounted on a color cathode ray tube according to a third embodiment of the present invention;

FIG. 6 is a perspective view, a front view, and a cross-sectional view after assembling a shadow mask structure mounted on a color CRT according to a third embodiment of the present invention;

FIG. 7 is a perspective view before assembling a shadow mask structure mounted on a fourth embodiment of the color cathode ray tube of the present invention.

FIG. 8 is a perspective view, a front view, and a sectional view of a shadow mask assembly mounted on a color CRT according to a fourth embodiment of the present invention after assembly.

[Explanation of symbols]

10, 20, 30, 40 Shadow mask structure 11, 21, 31, 41 Shadow mask 12, 22, 32, 42 Mask frame 13, 23, 33, 43 Schematic arc-shaped portion 14, 24, 34, 44 of mask frame Welding points 15, 25, 35, 45 Approximately arc-shaped portion of shadow mask 36 Bent portion of shadow mask tip 46 Emboss of shadow mask

Claims (5)

[Claims] 1. A mask frame comprising a pair of parallel flat plates corresponding to upper and lower ends of a screen of a color cathode ray tube and a pair of parallel flat plates corresponding to left and right ends of a screen connected and held, wherein a shadow mask is formed of the mask frame. In a color cathode ray tube, wherein a tension is applied between a pair of parallel flat plates corresponding to the upper and lower ends of the screen and the shadow mask is formed as a part of a cylindrical surface of an axis parallel to a vertical direction of the screen of the color cathode ray tube. The left and right ends of a pair of parallel flat plates corresponding to the upper and lower ends of the screen of the mask frame form substantially arc-shaped portions, and both ends corresponding to the left and right ends of the screen of the shadow mask are similar to the generally arc-shaped portions of the mask frame. A color CRT characterized by being formed into an arc shape. 2. The left and right ends of a pair of parallel flat plates corresponding to upper and lower ends of a screen of the mask frame, wherein portions of both ends corresponding to the left and right ends of the screen of the shadow mask correspond to upper and lower ends of the screen. A color cathode ray tube fixed to a substantially arcuate portion of the above. 3. A color cathode ray tube according to claim 1, wherein a bent portion is provided at a tip of a substantially arc-shaped portion at both ends corresponding to the left and right ends of the screen of the shadow mask. 4. The color cathode ray tube according to claim 3, wherein the bent portions of the shadow mask are two or more bent portions. 5. The color cathode ray tube according to claim 1, wherein the shadow mask has embossed portions at both ends corresponding to the left and right ends of the screen, which are formed in a substantially arc shape.