KR100270386B1 - Color cathode ray tube - Google Patents

Abstract

When the shadow mask is welded to the frame and adopted in the CRT, the skirt part near the position where color shift due to the doming phenomenon occurs is a short skirt part with a short skirt length, and the skirt projection part with the weld part between the frame and the shadow mask. By making the length longer and forming the inclined skirt portion from which the skirt length gradually decreases from the skirt protrusion portion to the short skirt portion, the mechanical strength of the shadow mask is increased, and the shadow mask is easily handled in the manufacture of the brown tube. A color cathode ray tube capable of preventing color shift due to thermal expansion of a shadow mask is provided.

Description

Color cathode ray tube

A cathode ray tube (hereinafter referred to as a color brown tube) used for color image display includes a panel portion which is an image screen, a neck portion for receiving an electron gun, and a funnel portion for connecting the panel portion and the neck portion, wherein the funnel portion is emitted from an electron gun. A deflection device is mounted which draws the electron beam onto the inner surface of the panel.

The electron gun accommodated in the neck portion includes various electrodes such as a cathode electrode, a control electrode, a focusing electrode, an acceleration electrode, and modulates an electron beam from the cathode by a signal applied to the control electrode, and the focusing electrode and the acceleration electrode. The cross-sectional shape and energy required are imparted to each other so that the fluorescent surface is sanded. The electron beam forms an image on the fluorescent surface by being deflected in the horizontal direction and the vertical direction by the deflection device formed in the funnel portion while reaching the fluorescent surface from the electron gun (Japanese Patent Laid-Open No. 59-215640). ).

When the electron beam radiated from the electron gun is color-coded so as to correspond to each color by the shadow mask disposed inside the panel portion, only the electron beam which is rounded to the fluorescent surface is rounded to the shadow mask. The energy of the electron beam becomes thermal energy because the electron beam is rounded off to the shadow mask. This thermal energy causes the temperature of the shadow mask to rise, causing thermal expansion.

Since the shadow mask is formed in a convex dome shape toward the panel and is surrounded by a frame, when the shadow mask causes thermal expansion, the shadow mask bulges toward the fluorescent surface, so-called doming phenomenon occurs.

As a countermeasure for the ming phenomenon, the shadow mask is generally made of an invar material having a low coefficient of thermal expansion. Use bimetal for spring. Shorten the skirt of the shadow mask. Etc. are performed.

When Invar material with a low thermal expansion coefficient is used for the material of a shadow mask, even in the shadow mask which is flat, since Invar material itself has the characteristic of low thermal expansion, the shadow mask can be suppressed from doming.

However, the Invar material, which has a low thermal expansion coefficient of the shadow mask material, has a strong spring phenomenon, and when pressing the shadow mask, spring back occurs in the shadow portion of the shadow mask, which makes it difficult to press the same shape as the designed value. Is caused. Moreover, since Invar material has a high cost, the cost of a CRT also increases.

When using a bimetal bonded with a material having different thermal expansion coefficients to a spring holding the shadow mask sphere, the shadow mask sphere is moved by using the bending of the bimetal material due to temperature fluctuations to balance the purity drift and the environmental temperature drift. In this way, the position where the electron beam passes through the shadow mask is aligned with the position where the electron beam passes.

However, since the bimetallic material is used for the mask spring, when the ambient temperature of the shadow mask sphere rises during the operation of the color receiver, the entire shadow mask sphere moves more than necessary, resulting in a beam landing error. there is a problem.

The shortening of the skirt portion between the welding fixing parts of the shadow mask has a configuration as shown in Japanese Patent Laid-Open No. 4-22048, for example.

Such a shadow mask improves the characteristics of the domming by shortening the skirt between the welding fixing parts than the welding fixing part. However, since the skirt width between the welding fixing parts of the shadow mask is narrow, the strength decreases and the shadow in the manufacturing process is reduced. Handling of the mask sphere becomes difficult.

In particular, for a shadow mask applied to a large cathode ray tube, an intensity such that the shadow mask does not deform is required.

If the skirt width is increased to obtain the strength, the dominant reduction effect is lowered due to thermal expansion of the skirt portion. In addition, there is a problem that deformation or doming phenomenon of the shadow mask sphere causes beam landing shift to degrade color purity.

In addition, in the color display tube used for the color monitor, it is necessary to increase the horizontal scanning player as compared to the color brown tube for the color television, and the heat generation in the shadow mask and the deflection yoke is large. The problem of color shift due to the doming phenomenon caused by the heat generation is a high-definition display cathode ray tube in which the hole pitch of the shadow mask that determines the dot pitch of the fluorescent surface is 0.31 mm or less, or substantially more than 1000 horizontal scan bows. This becomes more prominent and becomes an important problem.

An object of the present invention is to provide a color cathode ray tube which has a strength that is not deformed, has a low degree of deformation, and a reduction of the occurrence of beam landing errors.

(Initiation of invention)

When the shadow mask is welded to the frame and mounted on the CRT, shortening only the skirt portion near the position where color shift due to the doming phenomenon occurs and lengthening the other skirt portion increase the mechanical strength of the shadow mask, and thus the impact It is possible to provide a color cathode ray tube that is not deformed and that the shadow mask at the time of manufacturing a brown tube can be easily handled and that color shift due to thermal expansion of the shadow mask can be prevented.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a color cathode ray tube in which the occurrence of beam landing errors accompanying thermal expansion of a shadow mask sphere is reduced, and the strength reduction of the shadow mask is suppressed.

1 is a cross-sectional view of a cathode ray tube of the present invention,

2 is a schematic sectional view of a shadow mask sphere of the present invention;

3 is a schematic view of the shadow mask of the present invention as viewed from the panel side toward the cathode;

4 is a schematic diagram of a long edge portion showing an embodiment of a shadow mask sphere according to the present invention;

5 is a schematic cross-sectional view of a part of a shadow mask sphere showing a reduction effect of a ming phenomenon according to the present invention;

6 is a schematic view of a long edge portion showing another embodiment of the shadow mask sphere according to the present invention;

7 is a schematic view of a long edge portion showing another embodiment of the shadow mask sphere according to the present invention;

(The best form to carry out invention)

A color cathode ray tube having a shadow mask structure formed by welding and fixing a skirt portion of a shadow mask to a frame, the color cathode ray tube having a skirt portion and a skirt protrusion having the longest skirt length of the frame portion. What is necessary is just to have the inclined skirt part in which the skirt length becomes short gradually as it goes to a corner part in at least one part of the said skirt part.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described using drawing. In addition, it demonstrates with the same code | symbol to the same part.

1 is a cross-sectional view showing a schematic configuration of a cathode ray tube of the present invention, (1) a panel portion, (2) a funnel portion, (3) a neck portion, (4) a fluorescent surface (screen), (5) A shadow mask sphere having a shadow mask for color screening, (51) a panel pin for supporting the shadow mask sphere (5), (6) a magnetic shield for blocking the funnel space from the external magnetic field, (7) A deflection device (deflection yoke) for scanning the electron beam emitted from the electron gun on the fluorescent surface formed on the inner surface of the panel, (8) a purity adjustment magnet, (9) a center beam static convergence adjustment magnet, and (10) a side beam star Tick-combusence adjusting magnet, 11 is an electron gun, B is an electron beam.

The red, green, and blue electron beams B are deflected in the horizontal and vertical directions by the deflection yoke 7 disposed in the funnel portion 2 while reaching the fluorescent screen 4 from the electron gun. The electron beam B is color-coded so as to correspond to each color by a shadow mask disposed inside the panel portion, and each fluorescent surface emits light by forming a light on each panel to form an image on the panel surface.

2 is a schematic cross-sectional view of the shadow mask sphere 5 of the present invention, the shadow mask surface having an electron beam through hole is upward, and FIG. 3 shows the shadow mask of the present invention when viewed from the cathode side toward the panel portion 1. It is a schematic diagram. The shadow mask structure 5 includes a shadow mask 12 having a plurality of electron beam through holes for color selection, a frame 13 holding the shadow mask 12, and a mask holding the frame 13 in the panel. A spring 14 is provided, and the mask spring 14 disposed in the shadow mask sphere 5 is joined to and held by the panel pin 51 formed on the panel portion 1.

There is a welding fixing part of the shadow mask 12 and the frame 13 in the skirt portion near the position where the short axis passing through the center of the shadow mask 12 and the shadow mask long edge part intersect, and the center of the shadow mask 12 is located. There is also a welding fixing part of the shadow mask 12 and the frame 13 in the skirt part near the position where the constriction and shadow mask short edge part intersect, and the welding fixing part is also in the skirt part of a corner part.

Doming phenomenon is likely to occur in the middle portion between the short axis and the short edge of the shadow mask 12, and a large amount of doming does not occur near the short axis.

FIG. 4 is a schematic diagram showing the side surface of the long edge portion of the shadow mask 12 having the shadow mask surface 15 upward as an embodiment of the present invention.

Reference numeral 16 denotes a welded portion between the shadow mask 12 and the frame 13, and 17 denotes a skirt protrusion for welding with a welded portion 16 at the skirt long edge of the shadow mask 12 (hereinafter, referred to as a long portion). Edge protrusions), 18 are skirt protrusions for welding (hereinafter, corner protrusions) with welded portions at the corner portions of the shadow mask, and 19 are between the long edge protrusions 17 and the corner protrusions 18. FIG. The short skirt portion 20, which is located at, is located between the long edge protrusion 17 and the corner protrusion 18, and the inclined skirt portion adjacent to the long edge protrusion 17, and 23 is one edge of the shadow mask. The central axis in the direction L6 is the length in which the inclined skirt portion from the skirt central axis 23 with the protrusion is formed.

The skirt length of the long edge protrusion 17 of the shadow mask 12 corresponds to L1, the skirt length of the corner protrusion 18 corresponds to L2, and the long edge of the position where the doming characteristic of the middle portion between the short axis and the short edge becomes a problem. The length of the skirt is L3, the length of the skirt of the slanted skirt 20 is L4, the corner projection 18 and the long edge of the position where the problem of the dominant characteristics of the middle part of the short axis and the short edge where L3 is positioned is a problem. If the skirt length of the intermediate part with the corresponding position is L5, the relationship is L1> L4> L2≥L5≥L3.

That is, the inclined skirt portion 20 having the skirt projection portion 17 having the longest skirt length of the welding fixing portion between the skirt portion and the frame, and the skirt length being gradually shortened adjacent to the skirt projection portion 17 is provided. And a short skirt portion 19 having a skirt length shorter than the skirt length of the skirt projection portion 17 adjacent to the other end of the inclined skirt portion 20.

In addition, the dominant phenomenon is likely to occur in the middle portion between the short axis passing through the center of the shadow mask 12 and the short edge, and near the short axis, that is, near the long edge protrusion 17 having the welding fixing part 16. Since a large amount of troublesome doping does not occur, the short skirt portion 19 is formed at the middle of the long edge protrusion 17 and the corner protrusion 18 at least on the skirt long edge, thereby reducing the dominant phenomenon. Can be obtained.

Further, in order to reduce the dominant phenomenon from the middle of the long edge protrusion 17 and the corner protrusion 18 to the protrusion 18, it is preferable to form a short skirt portion 19 having a substantially constant skirt length. The short skirt portion 19 is not limited to the corner portion from the middle of the long edge protrusion portion 17 and the corner protrusion portion 18, and may be a short skirt portion at least in the vicinity of the dominant phenomenon.

If the inclined skirt portion 20 is formed up to a position beyond the midpoint between the long edge protrusion portion 17 and the corner protrusion portion 18, the area of the skirt portion is increased to cause a dominant phenomenon. Therefore, at least one part from the long edge protrusion 17 to the intermediate point between the long edge protrusion 17 and the corner edge protrusion 18 may have an inclined skirt portion in which the skirt length gradually changes.

For example, in the shadow mask 12 used for the diagonal color screen of 66 cm color, the material is aluminide (AK), plate thickness is 0.25 mm, L1 is 25 mm, L2 is 13 mm, L3 is 10 mm, When L6 at the long edge is set to 160 mm, on the two long edges, two points at the 110 mm position are restrained from the short axis, and the shadow mask 12 is placed on its own weight with the shadow mask surface 15 facing up. Stress was investigated. As a result, the shadow mask having the inclined skirt portion 20 is reduced about 35% in the vertical stress and about 96% in the tangential stress, as compared with the shadow mask without the inclined skirt portion 20.

At this time, the maximum value of the electron beam shift amount was about 60 µm three minutes after the start of operation. On the other hand, the maximum value of the electron beam shift in a color brown tube using a conventional shadow mask, i.e., a shadow mask which does not apply a skirt protrusion, a short skirt and an inclined skirt, was about 176 mu m five minutes after the start of operation. The color brown tube using the shadow mask applied with the skirt protrusion, the short skirt and the slanted skirt can significantly improve the shift amount of the electron beam compared to the color brown tube using the conventional shadow mask, and visually reduce the electron beam to a value without any problem. The shift amount of can be suppressed.

In addition, the shadow mask without the inclined skirt portion 20 causes deformation at about 100 mm from the short axis, and the deformation can be suppressed by forming the inclined skirt portion 20.

In FIG. 4, the inclined skirt portion in which the skirt length decreases linearly from the skirt center axis 23 to the short skirt portion 19 is described. However, a flat portion may be formed near the vertex of the protrusion.

Next, the operation will be described. At the time of sorting the shadow mask 12 so as to correspond to each color, the temperature of the shadow mask 12 is raised by the electron beam B which has fallen on the shadow mask 12 to cause thermal expansion.

The electron beam B does not step in the skirt portion of the shadow mask 12. Therefore, heat generated in the shadow mask 12 is transferred to the skirt portion by the heat conduction to raise the temperature of the skirt portion.

The skirt length of the short skirt section 19 is formed shorter than the skirt length L1 of the long edge projection 17. By shortening the skirt length, the volume of the skirt portion is reduced and the heat radiation area is reduced, so that the temperature of the shadow mask 12 is likely to rise. The thermal expansion of a skirt part becomes large by the one corresponded to this temperature rise.

For this reason, the difference between the temperature rise of the shadow mask surface 15 where the electron beam is dead and heat is generated and the temperature rise of the skirt portion 13 becomes small, and the entire shadow mask 12 is thermally expanded.

FIG. 5 is a schematic diagram showing a part of the shadow mask 12 of the present invention and a reduction effect of the ming phenomenon, and the dotted line 121 denotes the shadow mask 122 before thermal expansion and the shadow mask after thermal expansion.

The long edge protrusion 17 has a weld 16, which is fixed to the frame 13 by the weld 16.

The frame 13 has a larger heat capacity than the shadow mask 12 and takes time to thermally expand. On the other hand, since the shadow mask 12 is thin, the thermal conductivity is good, and therefore only the shadow mask 12 is thermally expanded. The shadow mask has a long length of the skirt of the long edge protrusion 17 having the welded portion 16, and is formed in a mechanically weak state by a half edge, etc., and the welded portion 16 is located below the protrusion, and the shadow mask The tolerance 121 in the frame outer diameter direction, which is a direction in which the external shape of the shadow mask is enlarged, can be large, and thermal expansion is performed like the shadow mask 122.

In other words, the tolerance in the frame outer diameter direction is large, so that the thermal expansion component of the effective surface portion of the shadow mask 12 is not absorbed by doming, but the component absorbed directly by enlargement of the appearance is increased, thereby reducing the amount of doming. Can be reduced.

In addition, since the skirt portion other than the welding fixing part is short, thermal expansion to the fluorescent surface is small, and the amount of domming can be reduced.

When the short skirt portion is increased, the strength against the stress of the shadow mask becomes weak, and the extreme change in the skirt length also causes deformation when stress is applied. Since the skirt length of the inclined skirt portion gradually becomes the skirt length of the short skirt, the strength of the skirt portion also changes gradually, and stress does not concentrate.

FIG. 6 shows another embodiment of the present invention, in which the same reference numerals are given to the same parts as those of FIG. 4.

The shadow mask 12 has a short skirt portion 19 and a long edge protrusion 17, and an inclined skirt portion adjacent to the long edge protrusion 17 has a curved portion 21 whose skirt length is curvilinearly reduced. . By forming in this way, the area of the skirt becomes small, the heat radiation amount is reduced, and the landing error of the electron beam caused by the dominant phenomenon can be suppressed, and the stress length is gradually changed from the short axis to the middle of the intensity. It can disperse, it can prevent the deformation of the shadow mask.

For example, in the shadow mask 12 used for the diagonal color screen of 66 cm color, the material is aluminide (AK), plate thickness is 0.25 mm, L1 is 25 mm, L2 is 13 mm, L3 is 10 mm, When L6 at the long edge is set to 160 mm, on the two long edges, two points at the 110 mm position are restrained from the short axis, and the shadow mask 12 is placed on its own weight with the shadow mask surface 15 facing up. Stress was investigated. As a result, the shadow mask using the inclined skirt portion 21 with the bent portion is reduced by about 24% in the vertical stress and about 70% in the tangential stress, compared to the shadow mask without the inclined skirt portion 21 with the curved portion. It is alleviated.

In addition, the maximum value of the electron beam movement amount at this time became about 58 micrometers after 3 minutes from the start of operation. On the other hand, the maximum value of the electron beam shift in a color brown tube using a conventional shadow mask, that is, a shadow mask which does not apply the skirt protrusion, the short skirt and the inclined skirt, was about 176 m after five minutes from the start of operation. The color brown tube using the shadow mask applied with the skirt protrusion, the short skirt and the slanted skirt can significantly improve the electron beam shift amount compared to the color brown tube using the conventional shadow mask, and visually reduce the electron beam to a value without any problem. The shift amount of was able to be suppressed.

In addition, the shadow mask without the inclined skirt portion 21 is deformed at about 100 mm from the short axis, and the deformation can be suppressed by forming the inclined skirt portion 21.

In addition, the inclined portion located between the protruding portion and the short skirt portion may include both a portion where the skirt length gradually decreases and a portion where the skirt length decreases linearly. You can get it.

7 shows another embodiment of the present invention, in which the same reference numerals are given to the same parts as in FIG. 4.

The shadow mask 12 has a short skirt portion 19, a long edge protrusion 17, and an inclined skirt portion 20 adjacent to the long edge protrusion 17, and the long edge protrusion 17 and the inclined skirt portion. A notch 22 is provided between the 20. By forming in this way, the area of the skirt becomes small, the amount of thermal radiation is reduced, and the landing error of the electron beam caused by the dominant phenomenon can be suppressed, and the stress length is gradually changed from the short axis to the middle part. It can disperse, it can prevent the deformation of the shadow mask.

For example, in the shadow mask 12 used for the diagonal color screen of 66 cm color, the material is aluminide (AK), plate thickness is 0.25 mm, L1 is 25 mm, L2 is 13 mm, L3 is 10 mm, When L6 at the long edge is set to 160 mm, two points at the 110 mm position are restrained from the short axis on two long edges, and the shadow mask 12 is held up by the weight of the shadow mask 12. The stress was investigated. As a result, the shadow mask using the inclined skirt portion 20 having the notched portion 22 is reduced by approximately 37% in the vertical stress compared to the shadow mask without the inclined skirt portion 20 having the curved portion, and in tangential stress. It is about 94% reduced.

In addition, the maximum value of the electron beam movement at this time became about 62 micrometers after 3 minutes from the start of operation. On the other hand, the maximum value of the electron beam shift in a color brown tube using a conventional shadow mask, i.e., a shadow mask which does not apply a skirt protrusion, a short skirt and an inclined skirt, was about 176 mu m five minutes after the start of operation. The color brown tube using the shadow mask with the skirt protrusion, the short skirt and the slanted skirt can significantly improve the shift amount of the electron beam compared to the color brown tube using the conventional shadow mask, and visually reduce the electron beam to a value without any problem. The shift amount of was able to be suppressed.

In addition, the shadow mask without the inclined skirt portion 20 having the notch portion 22 is deformed at about 100 mm from the short axis, and the notch portion 22 is formed by forming the inclined skirt portion 20. Strain can be suppressed.

As mentioned above, although the long edge skirt part was demonstrated, you may form a short edge protrusion part, a short skirt part, and the inclined skirt part also in the skirt short edge part of the shadow mask 12 which is not shown in the same way as the skirt long edge part.

In addition, although the case where the welding part was arrange | positioned near the skirt center was demonstrated, it is not limited to this, The welding part with the frame of a shadow mask is a protrusion part, and has the inclined skirt part which shortens a skirt length adjacent to this protrusion part, It is sufficient to have a short skirt portion of a skirt length shorter than the skirt length of the skirt projection portion adjacent to the other end of the inclined skirt portion.

By forming the inclined skirt portion from the protrusion to the short skirt portion, the strength against stress is strengthened. By forming in this way, the area of the skirt is small, the amount of heat radiation is reduced, and the intensity of stress can be dispersed by gradually changing the skirt length from the short axis to the middle, whereby the deformation of the shadow mask can be prevented.

In addition, the dominant phenomenon of the shadow mask can be suppressed and the landing error of the electron beam caused by the dominant phenomenon can be suppressed to the extent that there is no problem at all visually. In addition, it is possible to obtain a shadow mask having a strength that does not have any problem in manufacturing a CRT.

As described above, the color cathode ray tube according to the present invention has a shadow mask, and is suitable for a color cathode ray tube using a shadow mask which causes an electron beam to round the shadow mask and causes color shift due to thermal expansion of the shadow mask.

Claims (5)

A color cathode ray tube having a shadow mask structure formed by welding a skirt portion of a shadow mask to a frame, the skirt protrusion having a skirt length of the welding fixing portion between the skirt portion and the frame being the longest. And a short skirt portion adjacent to the other end of the inclined skirt portion, the short skirt portion having a shorter skirt length than the skirt protrusion portion. The color cathode ray tube according to claim 1, further comprising a portion of the inclined skirt portion of which the skirt length decreases linearly. The color cathode ray tube according to claim 1, wherein the slanted skirt portion having a curvilinear decrease in skirt length is provided in part. The color cathode ray tube according to any one of claims 1 to 3, wherein a notch portion is provided between the inclined skirt portion and the skirt protrusion portion. The color cathode ray tube according to claim 1, wherein the skirt projection is located on at least one of the long edge side and the short edge side.