JPH05128979A - Color cathode-ray tube - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a color cathode ray tube in which a color shift does not appear even when an impact or a vibration is applied from the outside. A brazing material for a color cathode ray tube having a shadow mask structure in which a shadow mask (11) having a large number of vertical grid elements arranged in parallel is attached to and held by a mask frame (10) by applying vertical tension. Then, the damper wire (13) previously coated with is installed by applying tension so as to intersect and closely adhere to the grid element body, and then the damper wire (13) and the grid element body are fixed by heat treatment. [Effect] Even if an external shock or vibration is applied to the color cathode ray tube, a large amplitude vibration does not occur in the shadow mask.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, even when subjected to vibration or shock from the outside, changes the amplitude of the relative position of the grid element of the shadow mask relative to the fluorescent surface formed on the inner surface of the panel due to the vibration or shock. The present invention relates to a color cathode ray tube which is extremely suppressed so that adverse effects such as color shift do not appear on a screen display.

[0002]

2. Description of the Related Art In a shadow mask type color cathode ray tube, as is well known, a fluorescent surface in which dots or stripes of fluorescent materials of three primary colors are repeatedly arranged in a predetermined order is provided on a back surface of a face plate portion of a panel. A shadow mask provided with an opening for passing an electron beam on the electron gun side is installed facing the fluorescent surface, and an electron gun for emitting a dedicated electron beam for each of the three primary colors is provided, and a specific opening of the shadow mask is provided. Since the specific primary color electron beam that has passed through the section intersects the shadow mask surface at a different predetermined angle for each primary color, after passing through the shadow mask, it is projected onto the dots or stripes of the specific primary color phosphor on the fluorescent surface. It is designed to strike and emit light.

In a color cathode ray tube used for a normal color television broadcast receiver, the number of pixels constituting one frame (however, one set of red, blue and green fluorescent bodies is included) is about 300,000 according to international standards. Therefore, as a shadow mask material, a mild steel plate having a plate thickness of about 0.2 mm or an iron-nickel alloy has been conventionally used. Since such a shadow mask has a sufficient plate thickness and is difficult to bend, even if the color cathode ray tube receives an external vibration or shock, there is almost no possibility that the relative position of the shadow mask with respect to the fluorescent surface changes. There was no problem if the periphery was fixed to a tough frame-shaped mask frame. However, a display terminal (VDT) of an information processing system is gradually required to have a color cathode ray tube having a high definition, and on the other hand, a color television broadcast of a high definition image called a so-called ADTV or HDTV is realized. It's getting closer.
In such a so-called high-definition color cathode ray tube, a number of pixels which is about several times the number of pixels defined by the current color television broadcasting standard is required, and the number of electron beam passage openings provided in the shadow mask is accordingly increased. I also have to do a lot.

Three electron guns dedicated to each primary color of the shadow mask type color cathode ray tube (strictly refer to an electron beam emitting portion, and a focusing electron lens and the like having a large diameter for three electron beams are commonly used. It doesn't matter)
Except in the very beginning, the method of arranging in a horizontal plane including the tube axis is mainly put into practical use. This is because so-called self-convergence can be expected.

While the electron guns are arranged in the same manner as described above, the methods are different for the fluorescent surface and the shadow mask. On the fluorescent surface, there are one in which dots of three primary color phosphors are repeatedly arranged in a predetermined order, and one in which stripes of three primary color phosphors continuous in the vertical direction are repeatedly arranged in a predetermined order. The shadow mask also has a circular shape for the electron beam passage opening, and the opening is vertically long, depending on whether the fluorescent body on the fluorescent surface is dot-shaped or stripe-shaped.
There are those in which lateral connecting portions are provided at a plurality of positions in the vertical direction for reinforcement, and those in which the vertical grid element bodies are arranged in parallel and arranged in parallel in the horizontal direction.

As described above, since the number of pixels is relatively small for television reception, the fluorescent surface in which the vertical stripes of the fluorescent body are arranged side by side and the vertical direction at a plurality of vertical positions in the horizontal direction. The most commonly used is a shadow mask in which electron beam passage openings having a lateral coupling portion for reinforcement are arranged at different positions in adjacent openings. This is because the image looks good and is easy to manufacture. Such a shadow mask has a material thickness of 0.20 m as described above.
Since it has sufficient self-shape retention at about m, it is usually sufficient to fix its peripheral portion to a durable mask frame, and it has been practically used without any problems.

However, in a high-definition tube, it is desirable to reduce the thickness of the shadow mask material because it is necessary to make openings at a short pitch. This is because a thin material is convenient in order to accurately form the electron beam opening according to a desired dimension by the etching method and to shorten the working time and improve mass productivity. .. Currently, materials up to about 25 μm are used as materials for shadow masks. Since a shadow mask made of such a thin material cannot be expected to retain its own shape, the shadow mask material must be attached to a durable mask frame by applying tension. At that time, if the shadow mask has a circular opening, tension may be applied in either the vertical or horizontal direction, but the opening is vertically long, especially if the vertical grid elements are arranged in parallel. In this case, when the tension is applied in the horizontal direction, the opening may be deformed, so that the tension can be applied only in the vertical direction. On the other hand, when a shadow mask in which vertical grid elements are arranged side by side is used, the diameter of the electron beam is quite large, and the display screen is detailed when the dot-type fluorescent surface and the circular-hole shadow mask are combined. The black gap between the upper and lower pixels, which can be seen when seeing, is not visible, and the display looks neat.
Although there are such advantages, this type of shadow mask can apply tension only in the vertical direction, so make the panel shape almost flat and combine it with a flat shadow mask, or The panel surface has a curved curved surface in the horizontal section and a linear curved surface in the vertical section (the cylindrical surface is in practical use), and a shadow mask stretched in a similar curved shape is used in combination.

In any of the above cases, a shadow mask in which vertical grid elements made of a thin material of about 25 μm are juxtaposed is used in the middle when the length of the grid elements in the vertical direction is considerable. If it is used without any support, the grid element body will continue for a while if the color cathode-ray tube is impacted or vibrated from the outside even if it is stretched with sufficient tension in the length direction (vertical direction). Vibration is likely to occur. On the other hand, since the color fluorescent surface is formed on the back surface of the face plate part of the hard panel made of glass,
The color cathode ray tube moves in the same way as an external shock or vibration. Therefore, the relative position between the opening of the shadow mask and the phosphor stripe of the fluorescent film fluctuates in an oscillating manner, and if the vibration width is large, a color shift occurs in the displayed image.

Since the color misregistration is ugly to the person who is viewing the image, in order to prevent the vibration that is continuously generated for a while for the grid element body or the shadow mask, it has hitherto been intersected with and closely contacted with the grid element body. As described above, the damper wire for damping the vibration within a short time is attached by applying tension via a leaf spring. As the damper wire, a thin and relatively strong tungsten wire having a wire diameter of about 10 to 30 μm is mainly used. Various proposals have heretofore been made regarding the mounting method of such a damper wire, for example, Japanese Patent Application Laid-Open No. 53-132.
Japanese Patent No. 259 discloses a technique in which the tension applied to the damper wire is reduced at high temperatures, and the tension recovers and becomes stronger at low temperatures.

[0010]

In the above technique, when a tungsten wire is used as the damper wire, the coefficient of thermal expansion of the tungsten wire is smaller than that of mild steel generally used as a material for a grid element, and at the time of high temperature. Oxides with a large friction coefficient are generated on the surface of the grid element body and the surface of the damper wire, respectively, and as a result, the two are fixed to each other at the contact portion, and the grid element interval is different at the points along the damper wire. It is intended to prevent the color misregistration that occurs because the deformation occurs shorter than the portion and the deformation remains as it is even when the temperature returns to a low temperature.

However, even by various proposals regarding the conventional installation method of the damper wire, the continuous vibration due to the external shock or vibration of the grid element body or the shadow mask is still sufficiently (to a worrisome degree). It couldn't be damped (so that the color shift didn't appear).

The present invention solves the above-mentioned problems of the related art, and receives a shock or vibration from the outside while using a shadow mask made of a thin material in which vertical grid elements are arranged in parallel to form an opening for passing an electron beam. It is an object of the present invention to provide a color cathode ray tube in which no noticeable color misregistration appears.

[0013]

In order to achieve the above object, according to the present invention, a mask frame is constructed by vertically tensioning a shadow mask in which a plurality of vertical grid elements are arranged in parallel and arranged in parallel in the horizontal direction. In a color cathode ray tube equipped with a shadow mask structure attached and held to a shadow mask structure, a thin wire previously coated with a brazing material is applied to the shadow mask structure by applying tension so as to intersect and adhere to the grid element body. After that, by heat treatment, the grid element body and the thin wires were fixed to each other with a brazing material.

[0014]

Function: Before, the manufacturing technology for large glass bulbs for cathode ray tubes had not been sufficiently developed, and so-called implosion accidents frequently occurred. Therefore, the face plate portion of the valve panel has a curved surface (mainly a spherical surface) that is convex outward. However, over the years after the start of television broadcasting, experience in manufacturing large numbers of glass bulbs has led to advances in implosion prevention technology and advances in glass bulb manufacturing technology. Valves are also becoming practical. When a color cathode ray tube is used, it is a cathode ray tube having a flat face plate portion that a normal image observer can easily see the image. Therefore, in recent years, due to the progress of the valve manufacturing technology, even large-sized pipes having gradually a flat or nearly flat face plate have become mainstream.

If the face plate portion of the glass bulb panel becomes flat, the shadow mask is inevitably flat or nearly flat. Therefore, a large shadow mask made of thin material, in which a number of vertical grid elements are arranged in parallel and arranged in parallel in the horizontal direction, is stretched in a flat plane, and the continuous continuation caused by external impact or vibration is used. It is necessary to damp such vibrations sufficiently rapidly (so that annoying color shift does not appear). Conventionally, damper wires have been attached so as to intersect and closely adhere to the grid element body for the above purpose, but when the tension state of the shadow mask becomes flat and becomes large, the shadow mask The damper wire can be brought into contact with the grid element body with a sufficient pressure at a position near the horizontal end of the shadow mask, but it becomes difficult to apply a sufficient pressure at a position near the center of the shadow mask. It is self-evident that the damper wire is effective because it is in contact with the grid element body with sufficient pressure, and otherwise it is not effective.

Since the cathode ray tube receives various impacts and vibrations from the outside, the grid element should also have various vibration directions. Of the vibrations, the color shift does not occur if only in the longitudinal direction of the grid element body, that is, the longitudinal vibration. The cause of color misregistration is vibration in a direction perpendicular to the length direction of the grid element, that is, lateral vibration. However, since the grid elements are fixed to the tough mask frame at both ends, longitudinal vibration is generated along with lateral vibration. In the case of the color cathode ray tube of the present invention, the damper wire is
Although it is fixed to the grid element at the intersection with the grid element, the resistance to flexural deformation cannot be considered because it is thin, and the elasticity of the leaf spring that is attached to the mask frame mainly by applying tension to the damper wire at both ends It acts by force to return it to its original position. When the damper wire is pressed against the grid element body as in the conventional case, the damper wire and the grid element body slide on each other at the contact part, and at that time, frictional force acts and the vibration energy is consumed. It is considered that the vibration width is suppressed and attenuated. Therefore, in the case of a completely flat shadow mask, it is difficult for the damper wire to contact the grid element with sufficient pressure except in the peripheral area. In some cases, the grid element may vibrate with a large amplitude in the central portion of the display image, resulting in a noticeable color shift. In the case of the present invention, since the damper wire and the grid element are fixed to each other at the intersection, the energy cannot be attenuated by the frictional force at the sliding portion. However, it has been confirmed by the present inventors that, when the present invention is carried out, when the color cathode ray tube is subjected to an impact or vibration from the outside, a color shift is less likely to appear than in the past. When the damper wire and the grid element are fixed by brazing,
The flow of the wax is different in the vicinity of each fixed point, the inertial mass of that point of the damper wire during lateral vibration is changed variously, and there is a similar flow of wax in the vicinity of each fixed point in the grid element, After all, although the original resonance frequency (vibration mode) of the partial vibration system formed by the grid element and the damper wire is different in the vicinity of each fixed point, they are actually connected to each other and are forced to have the same phase. Since it is forced to vibrate at, it seems that many vibration systems restrain each other and the amplitude is suppressed. Therefore, in the case of the present invention, the term "damper wire" is somewhat inappropriate, but it is in accordance with the conventional practice. Even if the grid element body is slightly deformed, the color shift does not always occur, and it depends on the vibration direction, but if the amplitude is less than a certain threshold value, the color shift does not occur. Even if the grid element continues to vibrate, there is no problem as long as its amplitude is below the threshold value that causes color shift. In reality, when deformed, there is no material that causes no internal energy loss, so the vibration energy in the shadow mask will soon disappear unless continuously supplied from the outside.

[0017]

1 is a schematic sectional view of a shadow mask type color cathode ray tube according to the present invention, in which 1 is a neck tube, 2 is a funnel, 3 is a panel, 4 is a valve, 5 is a face plate portion of the panel, 6 is a fluorescent surface, 7 is a shadow mask structure, 8 is an electron gun, and 9 is an electron beam. Fluorescent surface 6 is 3
It has a complicated fine structure in which dots or stripes of primary color phosphors are sequentially arranged in a predetermined order, and the fluorescent surface is a specific color formed by uniformly covering the entire back surface of the face plate part of the panel. Formed by photolithography technology that removes unnecessary parts after irradiating light passing through a shadow mask opening arranged opposite to a photosensitive film containing a fluorescent substance to solidify the necessary parts and fixing them to the glass surface of the panel. It For that purpose, the panel 3 is manufactured until all dots or stripes of each color phosphor on the fluorescent surface are formed as desired.
Must be separate from the funnel. The panel 3 is composed of a face plate portion 5 facing the image observer and a panel skirt portion bent at a substantially right angle around the face plate portion 5, and after the fluorescent surface is formed on at least the entire back surface of the face plate portion of the panel as described above. Then, the end face of the panel skirt portion and the end face of the funnel 2 are welded with a low melting point glass to complete the bulb 4. The electron beams 9 are emitted from three dedicated electron guns for a specific color arranged on a horizontal plane passing through the tube axis corresponding to each primary color. As described above, the electron beams for a specific color emitted from the three electron guns for a specific color arranged at different positions respectively pass through the specific electron beam passage opening of the shadow mask when passing through the shadow mask. And intersect at different angles. Therefore, even if the three electron beams pass through the specific electron beam passage openings of the shadow mask together, the three electron beams that have passed through the openings and are narrowed and narrowed there are different trajectories. To land on the dots or stripes of the phosphors of different specific colors forming the fluorescent surface to emit light.

FIG. 2 is a perspective view of a shadow mask structure used in one embodiment of the present invention. A shadow mask 11 in which a plurality of grid elements in the vertical direction are parallel to each other and are arranged in parallel in the horizontal direction.
Is attached to a mask frame 10 composed of a pair of horizontal frame sides 10a and 10b and vertical left and right arm portions 10c and 10d facing each other in a state in which tension is applied in the vertical direction. ing. The color cathode ray tube of the present invention is a high definition tube, and the shadow mask 11 has a plate thickness of 25 μm.
It is made of a mild steel plate of m and has a large number of vertical slits arranged in the horizontal direction by photolithography. When the shadow mask material is thin as described above, the slit forming work by the photolithography technique can be easily performed within a short time, and the welding work to the horizontal frame side of the mask frame is also easy. The slit width, that is, the electron beam passage opening width is shorter than the pitch between the slits. Therefore, the shadow mask 11 absorbs the kinetic energy of a large number of electrons that have been blocked from moving due to collision with the grid element body without passing through the openings among the moving electrons forming the electron beam, and heat is generated to raise the temperature. .. Even when the shadow mask is thermally expanded due to temperature rise, it is necessary to apply sufficient tension when the shadow mask 11 is initially attached to the mask frame 10 so that the shadow mask is not loosened and the desired shape can be maintained. Therefore, when installing, the horizontal frame edge 10a
And the vertical distance between 10b is
With the pressure applied from the outside to the mask frame 10 so that the mask frame 10 is contracted by a predetermined amount by the elastic deformation of 10d, the upper and lower peripheral portions of the shadow mask 11 are aligned with the horizontal frame side 10
After seam welding to a and 10b, the above pressure is removed so that the shadow mask 11 is tensioned by the elastic restoring force of the mask frame 10. A grid element or shadow mask having a length equal to or higher than the height of the display screen in the vertical direction and formed of a thin material with a plate thickness of about 25 μm should be applied with sufficient tension as it is as described above. Even if the cathode ray tube is stretched, when the cathode ray tube receives an impact or a vibration from the outside, it is likely to cause continuous vibration. In order to prevent or damp such vibration of the shadow mask, two damper wires 13 are applied to each other by a leaf spring 12 so as to intersect and closely contact the grid element body, and the left and right arms of the mask frame It is attached to the parts 10c and 10d. In this embodiment, the horizontal frame sides 10a and 10b of the mask frame are curved with a radius of curvature of 4000 mm so that the damper wire is in close contact with the entire surface of the shadow mask. In the present invention, unlike the conventional case, the diameter is 15 μm.
The surface of the damper core wire made of the tungsten wire is previously coated with a hard solder made of an aluminum alloy having a composition of Al 90% and Si 10% to a thickness of about 10 μm. This hard solder can be melted by heating at about 520 ° C. and the damper wire 13 can be fixed to the grid element body.

The diameter of the tungsten wire used for the damper core wire is about 10 to 20 μm, the thickness of the brazing material coating layer is about 5 to 10 μm, and the outer diameter after coating is 30 at maximum.
It is desirable to stop at about μm. This is because although it is thin, the electron beam is blocked by the damper line, a black shadow line appears on the display screen, and this black shadow line is confused with a part of the display depending on the type of display screen, which is an obstacle. Is.

As described in the section of the operation, in the shadow mask according to the present invention, even if the cathode ray tube receives an impact or a vibration from the outside, the shadow mask is composed of a large number of partial vibration systems having different resonance points. By virtue of the mutual drafting of those vibration systems, the amplitude is suppressed below the threshold value and the occurrence of color shift is prevented. The method of attaching the damper wire to the conventional shadow mask is different from the method of acting to suppress the amplitude by depleting the energy of vibration.

[0021]

As described above, according to the present invention, even if an external shock or vibration is applied to the color cathode ray tube, the shadow mask does not generate a large amplitude vibration, and therefore the color shift does not appear. ..

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a shadow mask type color cathode ray tube according to the present invention.

FIG. 2 is a perspective view of a shadow mask structure used in an embodiment of the present invention.

[Explanation of symbols]

1 ... Neck tube, 2 ... Funnel, 3 ... Panel, 4
… Valve, 5… faceplate part of panel, 6…
Fluorescent surface, 7 ... Shadow mask structure, 8 ... Electron gun,
9 ... Electron beam, 10 ... Mask frame, 10a,
10b ... Horizontal frame side, 10c, 10d ... Vertical arm part, 11 ... Shadow mask, 12 ... Leaf spring, 13
… Damper wire.

Front page continued (72) Inventor Hideo Tanabe 3300, Hayano, Mobara-shi, Chiba Hitachi Mobara factory (72) Inventor Masaki Shinoda 3300, Hayano, Mobara, Chiba Hitachi Ltd. Mobara factory (72) Invention Yuichi Kijima 3300 Hayano, Mobara-shi, Chiba Hitachi Ltd. Mobara factory

Claims (2)

[Claims] 1. A color cathode ray tube having a shadow mask structure in which a plurality of shadow masks in which vertical grid elements are arranged in parallel and arranged in the horizontal direction are attached to and held in a mask frame by applying a tension in the vertical direction, After applying a plurality of thin wires pre-coated with a brazing material to the shadow mask structure by applying tension so as to intersect and adhere to the grid element body, the grid element body and the thin wires are brazed by heat treatment. A color cathode ray tube characterized by being fixed by a material. 2. A brazing material for covering the thin wire is a hard brazing material made of an aluminum alloy.
The described color cathode ray tube.