JP2001023537A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a cylindrical shadow mask with a tensile force applied in a vertical direction of a screen from vibrating to generate a color drift due to an external vibration. SOLUTION: A color cathode-ray tube has a cylindrical shadow mask 11, and is provided with multiple incisions 12 on parts in the left and right ends of a screen, and vibration damping bodies 13 held by the incisions 12. This constitution damps vibration of the cylindrical shadow mask 11.

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 (dots) in an iron or iron-nickel alloy thin plate.
Is called a dot type shadow mask, and a shadow mask having a rectangular electron beam passage hole (slot) 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 high rigidity and can hold its shape independently, and does not require a special shape holding mechanism.

However, recently, there has been a tendency that the screen of a color cathode ray tube is made to have a part of a cylindrical surface close to a plane (hereinafter, "part of the cylindrical surface" is referred to as a "cylindrical surface") or a complete plane to make the screen easier to see. is there. For this purpose, the shape of the shadow mask must be changed from a spherical surface to a cylindrical surface or a plane.However, unlike a spherical surface mask, a shadow mask of a cylindrical surface or a plane has a low rigidity and cannot hold its shape by itself. Requires a holding mechanism. One example is an attempt to apply tension to a shadow mask and hold the shadow mask on a mask frame, as disclosed in Japanese Patent Application Laid-Open No. 8-77936.

[0004] If the shadow mask is not a cylindrical surface but a flat surface, the flat surface has a lower rigidity than the cylindrical surface, so that the mechanism for holding the shadow mask becomes extremely complicated. Furthermore, since the focus and convergence around the screen are greatly deteriorated, a deflection yoke, electronic lens,
It is necessary to greatly improve the focus circuit and the like. For this reason, a flat surface is not always better than a cylindrical surface, and a cylindrical surface is often more practical because it has a 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, when the shadow mask is a cylindrical surface (hereinafter referred to as a cylindrical shadow mask), the axis of the cylindrical surface is set. A tension can be applied in the direction along (the vertical direction of the color CRT screen, hereinafter referred to as the vertical direction), but in the direction perpendicular thereto (the horizontal direction of the color CRT screen, hereinafter referred to as the horizontal direction). It is impossible to apply tension, and it is also difficult to fix the left and right ends. If the left and right ends are forcibly fixed, wrinkles will occur in the shadow mask, causing large color misregistration and impractical.

However, if the left and right ends of the cylindrical shadow mask are not fixed but are free ends, the shadow mask resonates with external vibration from a speaker or the like and produces color misregistration even if strong tension is applied in the vertical direction. Not practical.

As means for preventing the resonance of the cylindrical shadow mask described above, JP-A-8-77936, JP-A-9-284767 and JP-A-9-274868 disclose a method for preventing the resonance of the cylindrical shadow mask. A structure for abutting a vibration damper is disclosed.

However, in the structure disclosed in the above-mentioned publication, it is necessary to manufacture a vibration damping body having a complicated shape, fix it to the mask frame with high accuracy, and abut against the shadow mask. In addition to the cost increase, an increase in weight 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 CRT having a cylindrical shadow mask capable of preventing resonance 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 a plurality of cuts are formed in portions corresponding to the left and right edges of the screen of the shadow mask; The vibration of the cylindrical shadow mask is attenuated by providing the vibration attenuator sandwiched between the cuts.

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. And a plurality of cuts in a portion corresponding to the left and right ends of the screen of the shadow mask, and a vibration attenuator sandwiched between the plurality of cuts.

According to a second aspect of the present invention, the notch and the vibration damper are fixed by welding.

According to a third aspect of the present invention, the notch and the vibration damper are welded to each other in a state where tension in the vertical direction of the screen is applied to portions of the shadow mask corresponding to left and right ends of the screen. It is characterized by being fixed.

According to a fourth aspect of the present invention, when the notch and the vibration damping member are fixed by welding, a tension is applied to a portion corresponding to a left and right end of the screen of the shadow mask in a vertical direction of the screen. Is different from the strength of the tension when the shadow mask is fixed between a pair of parallel flat plates corresponding to the upper and lower ends of the screen of the mask frame.

According to a fifth aspect of the present invention, the vibration damping body is one of a square, a rectangle, a circle, an ellipse, and a triangle each having a schematic cross section, and the length is the shadow mask. The bar is substantially equal to the vertical direction of the screen.

[0016]

According to the first aspect of the present invention, a plurality of cuts are provided in portions corresponding to the left and right ends of the screen of the shadow mask, and a vibration damping body is sandwiched between the plurality of cuts.
Since a weight having a large inertial mass is attached to the left and right ends of the shadow mask, the resonance frequency moves to a lower side than that of a simple shadow mask. By appropriately selecting the mass of the vibration attenuator, the resonance frequency of the shadow mask can be moved out of the frequency range of the speaker, which is mainly a problem. Thus, even if the cylindrical shadow mask is applied with tension only in the vertical direction and fixed by welding to the mask frame, the resonance and color misregistration of the shadow mask can be reduced to practically acceptable levels.

Further, in the above configuration, only a slight design change is made to the existing shadow mask, so that the weight increase and the cost increase are not so significant.

Further, in the case of a configuration in which the vibration damping member is simply sandwiched between the cuts, it cannot be said that there is no danger that the vibration damping member will be slightly displaced over a long period of time and the resonance frequency of the shadow mask will change accordingly. However, when the notch and the vibration damping body are fixed by welding after the vibration damping body is sandwiched as in the second invention, the above-mentioned fear is eliminated and reliability is further improved.

Further, as in the third invention, when the notch and the vibration damping member are fixed by welding in a state where tension in the vertical direction of the screen is applied to portions corresponding to the left and right ends of the screen of the shadow mask, the vibration damping member is formed. Since the vertical tension is applied to the shadow mask from above, a shadow mask having a different resonance frequency can be realized even with the use of the vibration damping body having the same inertial mass.

Further, as in the fourth invention, the strength of the tension applied vertically to the left and right ends of the shadow mask by the vibration attenuator and the shadow mask is fixed between a pair of upper and lower parallel flat plates of the mask frame. If the strength of the tension is different, two different tensions are applied to the shadow mask, so that a shadow mask having a different resonance frequency in a wider range can be realized even if a vibration damper having the same inertial mass is used.

As described in the fifth aspect, the specific shape of the vibration damping member is one of a square, a rectangle, a circle, an ellipse, and a triangle, each of which has a rough cross section, and the length is a shadow. A rod that is substantially equal to the vertical direction of the mask is preferable because the above-mentioned effect is sufficiently obtained, design and manufacture are easy, and the cost is low.

[0022]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a perspective view and an enlarged view of a part A before assembling for explaining the structure of a shadow mask structure 10 mounted on a first embodiment of a color cathode ray tube according to the present invention, and FIG.
It is a perspective view after assembling. In the figure, reference numeral 11 denotes a shadow mask, 12 denotes cuts on the left and right ends of the shadow mask, 1
3 is a vibration damper, 14 is a cut 12 and a vibration damper 13
, A welding point, 15 is a slot, 16 is a mask frame,
Reference numeral 17 denotes a welding point between the shadow mask 11 and the mask frame 16. 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 CRT.
The screen is located above the perspective view. The material of the shadow mask 11 is an Invar alloy (36% nickel-iron alloy), and the materials of the vibration damper 13 and the mask frame 16 are 13% chrome stainless steel.

The manufacturing process of the shadow mask structure 10 of this embodiment will be described below.

As shown in FIG. 1, cuts 12 are formed in the left and right ends of the shadow mask 11 on which the slot 15 has been processed by pressing. Next, the cuts 12 are opened alternately, and the vibration damping body 13 is inserted into the gap, and the cut 1 is cut.
Then, the vibration damping body 13 is sandwiched by the closed cut 12. In this embodiment, the shape of the vibration damping body 13 is a flat bar having a rectangular cross section with a small thickness and a length substantially equal to the vertical direction of the shadow mask 11. In addition, as for the shape of the vibration damping body 13, a bar whose cross section is one of a rough square, a circle, an ellipse, and a triangle and whose length is substantially equal to the vertical direction of the shadow mask is the same as that of the present embodiment. Advantageous effects are obtained, design and manufacture are easy, and the cost is low, which is preferable.

Next, while applying a vertical tension to the left and right ends of the shadow mask 11, the cut 12 and the vibration damper 1 are applied.
3 is point-welded at a welding point 14. It is desirable that the tension at this time be different from the tension applied to the shadow mask 11 when the shadow mask 11 is later welded to the mask frame 16. The reason is that when two different tensions are applied to the shadow mask 11, the resonance frequency of the shadow mask 11 can be changed over a wide range. This is because it becomes easy to remove.

Next, as shown in FIG. 2, while applying vertical tension to the upper and lower ends of the shadow mask 11 to which the vibration damping body 13 is fixed by welding, the vicinity of the upper and lower ends of the shadow mask 11 is welded to the mask frame 16. At 17 point welding. The shadow mask 11 has a cylindrical shape following the welding surface of the mask frame 16. Thus, the shadow mask structure 10 of the present embodiment is completed.

After that, the color CRT of the present invention is completed by mounting the shadow mask structure 10 on the color CRT by a usual method.

Next, another embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 shows a shadow mask structure 2 mounted on a color CRT according to a second embodiment of the present invention.
A perspective view before assembling for explaining the structure of FIG.
FIG. 4 is a perspective view of the shadow mask structure 20 after assembly. In the figure, 21 is a shadow mask, 22 is a cut in the left and right ends of the shadow mask, 23 is a vibration damping body, 24 is a welding point between the cut 22 and the vibration damping body 23, 25 is a slot, 26 is a mask frame, and 27 is a shadow mask 21. And the welding point of the mask frame 26. The X direction indicates the horizontal direction of the screen of the CRT, and the Y direction indicates the vertical direction of the screen of the CRT. The screen is located above the perspective view. The material of the shadow mask 21 is an invar alloy (36% nickel-iron alloy), the vibration damping body 2
3 and the material of the mask frame 26 are 13% chrome stainless steel.

The manufacturing process of the shadow mask structure 20 of this embodiment will be described below.

As shown in FIG. 3, cuts 22 are formed in the left and right ends of the shadow mask 21 on which the slot 25 processing has been completed by pressing. Next, the cuts 22 are opened alternately, and the vibration damping body 23 is inserted into the gap, so that the cuts 2 are formed.
2 is closed so as to return to its original position, and the vibration damping body 23 is clamped by the closed cut 22. In this embodiment, the vibration attenuator 23 is a rod having a circular cross section and a length substantially equal to the vertical direction of the shadow mask 21. In addition, as the shape of the vibration attenuator 23, a bar whose cross section is one of an approximate square, rectangle, ellipse, or triangle and whose length is substantially equal to the vertical direction of the shadow mask is the same as that of the present embodiment. Advantageous effects are obtained, design and manufacture are easy, and the cost is low, which is preferable.

Next, while applying a vertical tension to the left and right ends of the shadow mask 21, the cut 22 and the vibration damper 2 are applied.
3 is point-welded at a welding point 24. It is desirable that the tension at this time be different from the tension applied to the shadow mask 21 when the shadow mask 21 is later welded to the mask frame 26. The reason is that when two different tensions are applied to the shadow mask 21, the resonance frequency of the shadow mask 21 can be changed over a wide range. This is because it becomes easy to remove.

Next, as shown in FIG. 4, while applying vertical tension to the upper and lower ends of the shadow mask 21 to which the vibration damper 23 is fixed by welding, the vicinity of the upper and lower ends of the shadow mask 21 is welded to the mask frame 26. At 27, point welding is performed. The shadow mask 21 has a cylindrical shape following the welding surface of the mask frame 26. Thus, the shadow mask structure 20 of the present embodiment is completed.

After that, the color CRT of the present invention is completed by mounting the shadow mask structure 20 on the color CRT by a usual method.

[0034]

As described above, according to the present invention, it is possible to provide a high-quality color cathode-ray tube which realizes the prevention of vibration of a cylindrical shadow mask to which tension is applied in the vertical direction of the screen with an inexpensive and lightweight configuration.

[Brief description of the drawings]

FIG. 1 is a perspective view and a partially enlarged view of a shadow mask assembly mounted on a color cathode ray tube according to a first embodiment of the present invention before assembly.

FIG. 2 is a perspective 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 and a partially enlarged view of a shadow mask assembly mounted on a color cathode ray tube according to a second embodiment of the present invention before assembly.

FIG. 4 is a perspective view after assembling a shadow mask structure mounted on a color cathode ray tube according to a second embodiment of the present invention;

[Explanation of symbols]

 10, 20 Shadow mask structure 11, 21 Shadow mask 12, 22 Notch 13, 23 Vibration damper 14, 24 Welding point 15, 25 Slot 16, 26 Mask frame 17, 27 Welding point

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. A color cathode ray tube comprising: a plurality of cuts in portions corresponding to left and right ends of a screen of a shadow mask; and a vibration attenuator sandwiched between the plurality of cuts. 2. A color cathode ray tube according to claim 1, wherein said cuts and said vibration damper are fixed by welding. 3. The method according to claim 2, wherein the notch and the vibration damping member are fixed by welding in a state in which tension in a vertical direction of the screen is applied to portions corresponding to left and right ends of the screen of the shadow mask. Characteristic CRT. 4. The method according to claim 3, wherein the strength of the tension applied in the vertical direction of the screen to a portion corresponding to the left and right ends of the screen of the shadow mask when the cut and the vibration damping body are fixed by welding is: A color cathode ray tube, wherein the shadow mask has a different tension strength when fixed between a pair of parallel flat plates corresponding to upper and lower ends of a screen of the mask frame. 5. The screen according to claim 1, wherein said vibration damper has a cross section of one of a square, a rectangle, a circle, an ellipse, and a triangle, each of which has a schematic length. A color cathode-ray tube characterized by being a rod almost in the same direction.