JP2003036800A - Color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color cathode-ray tube of which the shadow mask is capable of avoiding localized deformations in the main face due to deformations of its mask frame. SOLUTION: In this a color cathode-ray tube, a mask frame 6 composing a shadow mask structure is reinforced by welding reinforcements 60 on its major side flanges 6LF and minor side flanges 6SF in order to improve stiffness for such deformations as twist and slack.

Description

Detailed Description of the Invention

[0001]

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 having a main surface on which an electron beam passage hole is formed and having a substantially flat surface, which suppresses the surface deformation of the color selection electrode to prevent color shift. The present invention relates to a color cathode ray tube capable of displaying a fine image.

[0002]

2. Description of the Related Art Color cathode ray tubes, such as color televisions,
Widely used in color display monitors for OA equipment terminals. As this color cathode ray tube, the one having a color selection electrode usually called a shadow mask for controlling the collision of a plurality of electron beams emitted from an electron gun onto a fluorescent film is mainly used.

A color cathode ray tube (shadow mask type color cathode ray tube) provided with this color selection electrode (hereinafter referred to as a shadow mask) has a screen having a large number of dot-shaped or stripe-shaped fluorescent films coated on its inner surface. A vacuum envelope is formed by a rectangular panel portion, a substantially tubular neck portion that houses the electron gun, and a substantially funnel-shaped funnel portion that connects the neck portion and the panel portion. In this vacuum envelope, a shadow mask having a large number of electron beam passage holes is closely fixed to the phosphor film and fixed to a frame-shaped support member (hereinafter referred to as a mask frame).

[0004]

Aluminum-killed steel is mainly used as a constituent material of a shadow mask, but a high-definition color cathode ray tube is used to press-form a thin base material. So-called flat masks, whose main surface is a substantially flat surface, have been widely adopted. In the color cathode ray tube using this flat mask, the mask frame is deformed by the application of an external force, so that the main surface of the shadow mask, which is a perforated region, is locally deformed. As a result, the impingement position of the electron beam on the fluorescent film is displaced, and the color purity is deteriorated.

In such a shadow mask, an original plate having a large number of electron beam passage holes formed at predetermined positions by etching is punched into a predetermined shape and then press-shaped to form a main surface having electron beam passage holes, and A panel is formed as a shadow mask assembly by shaping it into a shape that has a skirt portion that is continuous with the periphery of the main surface and that is bent at about 90 degrees in the direction of the electron gun with respect to the main surface, and welds and fixes this to the mask frame. Suspended on the inner wall of the department.

FIG. 11 is a perspective view illustrating an example of the structure of the shadow mask structure. The shadow mask 5 has a rectangular shape having a large number of electron beam passage holes 50 on its main surface, and the periphery of this main surface is bent by about 90 ° toward the electron gun to form a skirt portion 51. A shadow mask assembly (shadow mask structure) is fixed by welding to the mask frame 6. The side wall of the mask frame 6 is provided with a suspension spring 7 having one end fixed and the other end suspended by a stud pin 8 planted on the inner wall of the panel portion.

12A and 12B are explanatory views of the cross-sectional shape of a shadow mask. FIG. 12A shows a cross section of a conventional curved mask, and FIG. 12B shows a cross section of a recent flat mask. Reference numeral 5 in FIG. 12 indicates a shadow mask, and reference numeral 5M indicates a main surface, that is, a perforated region in which an electron beam passage hole is formed.
K is a skirt part. In the case of the conventional curved mask whose main surface has a curved surface shown in FIG. 12A, the shadow mask itself has a deformation resistance, and therefore the shadow mask 5 is applied when an external force is applied to the mask frame. Deformation such as twisting or bending is unlikely to occur, and the main surface is also difficult to deform. However, as shown in (b), the main surface of the flat mask is 5M.
Is nearly flat, and the rigidity of the shadow mask itself is small, so that deformation such as twisting and bending as described above is likely to occur, and deformation of the main surface as described later is likely to occur.

FIGS. 13A and 13B are explanatory views of the modification of the flat mask. FIG. 13A is a plan view and FIG. 13B is a sectional view taken along the line AA of FIG. Shadow mask (flat mask)
5 has a slight non-hole portion 5F around the main surface 5M, and a skirt portion 5K is bent in the electron gun direction outside the non-hole portion 5F. Since the shadow mask 5 is held by welding the skirt portion to the mask frame 6, when external force is applied to the mask frame 6 to cause twisting or bending, the shadow mask 5 as indicated by an arrow in FIG. Main surface of 5M
The local part of is deformed into a concave shape.

As described above, the shadow mask 5 is welded to and held by the mask frame 6, but external force is applied to the shadow mask via the mask frame. 14A and 14B are explanatory views of a mask frame that has been conventionally used. FIG. 14A is a plan view and FIG. 14B is a sectional view taken along line AA of FIG. The mask frame 6 is a frame-shaped member,
Long side 6 that roughly matches the outer shape of the shadow mask skirt
It has L and a short side 6S, and has a flange (long side flange 6LF, short side flange 6SF) which is bent in a direction substantially parallel to the plane of the shadow mask 5 on the side of the electron gun on the side wall. The skirt portion of the shadow mask is welded to the inner walls of the short side 6S and the long side 6L on the side of the fluorescent film. A frame opening 6H for passing an electron beam is formed inside the flange.

FIG. 15 is an explanatory diagram of the deformation that occurs in the mask frame. This deformation of the mask frame causes local deformation on the main surface of the shadow mask described in FIG. In FIG. 15, 6L is the long side of the mask frame, and 6L
S is the short side of the mask frame, 6P is an imaginary line showing the flat surface of the mask frame surface, 6D is the imaginary line of the deformed mask frame surface, D is the deformation direction, and ZZ is the tube axis direction orthogonal to the mask frame surface. Indicates.

FIG. 15 (a) is an explanatory view of the twist deformation, and shows the twist deformation in the D direction at each of the four corners of the mask frame. Particularly, the plate thickness of the mask frame used for the flat mask is about 1.6 mm,
The plate thickness of the shadow mask welded to this mask frame is about 0.12 mm to 0.26 mm. The mechanical strength of such a thin mask frame is very small. Therefore, when the mask frame is twisted, the shadow mask is deformed as shown in FIG. 13 due to the deformation of the mask frame.

FIG. 15 (b) shows the case where the deformation in the direction of the arrow D occurs at one corner of the mask frame. Also,
FIG. 15C shows the case where the opposite corners of the short side 6S are similarly deformed, that is, twisted. The deformation of the shadow mask causes the deformation of the shadow mask as described with reference to FIG. One of the problems is to avoid such deformation of the shadow mask.

Incidentally, as a disclosure of a countermeasure against the deformation of the shadow mask structure, Japanese Patent Laid-Open No. 49-11256.
6, JP-A-63-271849, JP-A-1
No. 169847, JP-A-9-35657,
Etc. can be mentioned. However, these publications focus on the structure of the shadow mask itself, and do not take measures against deformation of the mask frame.

An object of the present invention is to provide a color cathode ray tube provided with a mask frame having a structure for avoiding deformation of the main surface of the shadow mask.

[0015]

To achieve the above object, the present invention provides a structure for suppressing deformation such as twisting or bending by attaching a reinforcing material to a flange of a mask frame constituting a shadow mask structure. To improve the strength.
The typical configuration of the present invention is as follows.

That is, according to the present invention, there is provided a vacuum envelope having a substantially rectangular panel portion having a fluorescent film formed on the inner surface thereof, a neck portion accommodating an electron gun, and a funnel portion connecting the neck portion and the panel portion. A substantially rectangular shape having a skirt portion that is formed into a frame shape by bending from the periphery of the long side and the short side of the main surface facing the fluorescent film and having a plurality of electron beam passage holes formed, and bending toward the neck portion. A color cathode ray tube comprising a frame-shaped mask frame for holding a color selection electrode and a skirt portion of the color selection electrode by welding, the mask frame being substantially the same as the outer shape of the skirt portion of the color selection electrode. A side wall having a long side and a short side for welding the skirt portion of the color selection electrode to the fluorescent film side, and bent in a direction substantially parallel to the plane of the color selection electrode on the electron gun side of the side wall. With flange , Characterized by comprising a reinforcing member which is fixed to the flange extends continuously in the short side and the long side.

Of the long and short sides of the mask frame,
At least the mass of the reinforcing material provided on the long side is larger in the central portion than the end portion on the short side side, or the flange is provided with a recess for mounting the reinforcing material. The shape of this recess matches the shape of the reinforcing material to be attached.

Further, a step portion for mounting a reinforcing material is formed on the flange or an inclined portion is provided. Alternatively, the reinforcing material is discontinuous at the central portion on the short side. The reinforcing material is attached to the electron gun side of the flange, and this reinforcing material is used as a mounting member for the inner shield.

With such a structure, it is possible to avoid deformation of the main surface of the shadow mask, suppress electron beam collision errors, and obtain a color cathode ray tube with more stable performance.

It is needless to say that the present invention is not limited to the above-mentioned constitution and the constitution of the embodiments to be described later, and various modifications can be made without departing from the technical idea of the present invention.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described in detail with reference to the drawings of the embodiments. FIG. 1 is a plan view of a mask frame constituting a shadow mask structure for explaining a first embodiment of the present invention. In the figure, reference numeral 6
Is a mask frame, and is composed of a rectangular frame-shaped member having a long side 6L and a short side 6S that substantially match the outer shape of the skirt portion of the shadow mask. The mask frame 6 has a side wall 6LW having a long side 6L and a side wall 6SW having a short side 6S and a skirt portion of a shadow mask welded to the fluorescent film side.

On the electron gun side of the side wall 6LW and the side wall 6SW, there are provided flanges 6LF and 6SF bent inward in a direction substantially parallel to the plane of the shadow mask.
An opening 6H through which an electron beam passes inside surrounded by 6SF
Is formed. A reinforcing member 60 is fixed to the electron gun side, which is the back surface of the flanges 6LF and 6SF. The reinforcing member 60 is made of the same iron-based material as the mask frame 6, and has a flange 6L.
F and 6SF have the same rectangular sectional shape in the longitudinal direction.

The reinforcing material 60 is welded and fixed to the flanges 6LF and 6SF at several places. Welded parts are indicated by crosses. In the present embodiment, the reinforcing member 60 is a pair of U-shaped members that are discontinuous at the substantially central portion of the short side 6SW. The reinforcing material 6
It is needless to say that 0 is not limited to such a discontinuous member, and may be a square-shaped member that circulates on the back surface of the flanges 6LF and 6SF. This also applies to each of the following embodiments.

FIG. 2 is a partial cross-sectional view taken along line aa of FIG. 1, showing a shadow mask welded to the phosphor screen side of the side wall of the mask frame. Although FIG. 2 shows the long side, the cross section of the reinforcing material attachment portion on the short side is also the same, so only the long side will be described here. A recess 6 formed by pressing is formed on the back surface (electron gun side) of the flange 6LF of the mask frame.
G is formed, and a reinforcing material 60 having a shape that matches the inner shape of the recess 6G is attached to the recess 6G and welded. Weld points are indicated by crosses. The reinforcing member 60 of this embodiment is wide in the surface direction of the flange.

With this structure, the rigidity of the mask frame is improved, and deformation such as twisting and bending due to the application of external force is suppressed. Therefore, the above-described deformation of the shadow mask 5 is prevented.
Further, since the recess 6G is formed in the flange 6LF, the rigidity of the mask frame itself is improved, and the deformation as described above is suppressed in synergy with the effect of the reinforcing member. Further, the inner shield 9 that shields the geomagnetism and the like can be attached to the reinforcing member 60. According to the present embodiment, the deformation of the main surface of the shadow mask is avoided, and the collision error of the electron beam is suppressed,
A color cathode ray tube with more stable performance can be obtained.

FIG. 3 is a plan view of a mask frame constituting a shadow mask structure for explaining the second embodiment of the present invention. 4 is a partial cross-sectional view taken along the line aa of FIG. 3, showing a shadow mask welded to the phosphor screen side of the side wall of the mask frame. Similar to FIG. 2, FIG. 4 shows only the long side of the mask frame, but the cross section of the reinforcing material attachment portion on the short side is also the same, so only the long side will be described here. 3 and 4 that are the same as those in FIGS. 1 and 2 indicate the same functional parts.

In the reinforcing material 60 of this embodiment, the reinforcing material 60 installed on the flange 6LF on the long side 6LW side is the long side 6LW.
It is wide in the center. Its schematic shape is a U-shape similar to that of the first embodiment. The stress such as the twist of the mask frame 6 is maximum in the central portion on the long side 6L side. In accordance with this, the reinforcing material 60 is widened in the central portion of the long side 6LW. The height in the tube axis direction may be increased by changing the width.

This embodiment prevents the shadow mask 5 from being deformed as described above. Further, since the recess 6G is formed in the flange 6LF, the rigidity of the mask frame itself is improved, and the deformation as described above is suppressed in synergy with the effect of the reinforcing member. Further, as in the first embodiment, the reinforcing member 60 may be provided with the inner shield 9 that shields the earth's magnetism and the like. This makes it possible to avoid deformation of the main surface of the shadow mask, suppress electron beam collision errors, and obtain a color cathode ray tube with more stable performance.

FIG. 5 is a sectional view of an essential part of a mask frame which constitutes a shadow mask structure for explaining the third embodiment of the present invention, and shows a sectional view similar to FIG. 2 or FIG. In this embodiment, the step 6T is formed on the flange 6LF of the mask frame, and the reinforcing material 60 is attached to the step 6T. Other configurations are the same as those of the first and second embodiments. Also according to the present embodiment, the deformation of the mask frame is suppressed due to the improvement of the rigidity of the mask frame itself due to the step 6T, the deformation of the main surface of the shadow mask is avoided, and the electron beam impingement error is suppressed and more stable performance is achieved. It is possible to obtain a color cathode ray tube. In this embodiment, the inner shield is mainly attached directly to the flange 6LF.

FIG. 6 is a sectional view of an essential part of a mask frame which constitutes a shadow mask structure for explaining a fourth embodiment of the present invention, and shows the same sectional view as FIG. 2, FIG. 4 or FIG. In this embodiment, the mask frame flange 6LF has two
A step 6T 'is formed on the step, and a reinforcing material 60 is formed on the step 6T'.
Is attached. This reinforcement 60 is a flange 6L
It has a cross-sectional shape that conforms to the two steps 6T ′ formed in F. Other configurations are the same as those of the first to third embodiments. Also in this embodiment, the deformation of the mask frame is suppressed due to the improvement of the rigidity of the mask frame itself due to the two steps 6T ′, the deformation of the main surface of the shadow mask is avoided, and the collision error of the electron beam is suppressed. A color cathode ray tube with more stable performance can be obtained. In this embodiment, the inner shield is the flange 6LF and the reinforcing material 60.
It is attached to either or both.

FIG. 7 is a sectional view of an essential part of a mask frame which constitutes a shadow mask structure for explaining a fifth embodiment of the present invention, and is a sectional view similar to FIGS. In this embodiment, a sloped surface 6C is formed at a transition portion between the flange 6LF and the long side 6LW of the mask frame, and the reinforcing material 60 is formed on the sloped surface 6C.
Is attached. Other configurations are the first and second
It is similar to the embodiment. Also according to the present embodiment, the deformation of the mask frame is suppressed due to the improvement in the rigidity of the mask frame itself due to the slope 6T, the deformation of the main surface of the shadow mask is avoided, and the mistaken collision of the electron beam is suppressed, resulting in more stable performance. It is possible to obtain a color cathode ray tube. In addition,
In this embodiment, the inner shield is mainly the flange 6.
Attached directly to LF.

FIG. 8 is a sectional view of an essential part of a mask frame which constitutes a shadow mask structure for explaining a sixth embodiment of the present invention, and is a sectional view similar to FIGS. 2 to 7. In this embodiment, a reinforcing material 60 'having a circular cross section is used instead of the reinforcing material having a rectangular cross section in the first embodiment. Flange 6
The LF has a concave portion 6G 'having a curved surface that matches the outer shape of the reinforcing member 60'. It should be noted that instead of the reinforcing member 60 ′, a hollow member as shown in FIG. Also according to the present embodiment, the deformation of the mask frame is suppressed due to the improvement of the rigidity of the mask frame itself due to the concave portion 6G ′, the deformation of the main surface of the shadow mask 5 is avoided, and the collision error of the electron beam is suppressed to be more stable. It is possible to obtain a color cathode ray tube having the above performance. In this embodiment, the inner shield is the flange 6LF and the reinforcing material 60.
It is attached to either or both. Similar to FIG. 3, the reinforcing member 60 ′ and the recess 6G ′ can have a larger deformation preventing effect by increasing the size at the central portion of the long side.

FIG. 9 is a sectional view of a main part of a mask frame which constitutes a shadow mask structure for explaining a seventh embodiment of the present invention, and is a sectional view similar to FIGS. 2 to 8. In this embodiment, a reinforcing material is directly welded to the back surface of the flange 6LF, and the recesses and the like as in each of the above embodiments are formed on the flange 6L.
Not in LF. When the material of the mask frame is improved so that the concave portion is not required, this structure can also obtain a sufficient deformation preventing effect.

FIG. 10 is a sectional view for explaining an example of the overall structure of the color cathode ray tube of the present invention. Panel 1 and neck 2
The funnel portion forms a vacuum envelope. A fluorescent film 4 is coated on the inner surface of the panel portion 1, and a shadow mask 5 having a large number of electron beam passage holes is provided in proximity to the fluorescent film 4. The shadow mask 5 is fixed to a mask frame 6, and a free end of a suspension spring 7 whose one end is fixed to an outer wall of the shadow mask 5 is locked to a stud pin 8 planted in the inner wall of the panel portion 1.

On the electron gun side of the mask frame 6, an inner shield 9 for shielding the earth's magnetism and the like is attached. Further, reference numeral 10 is an anode button, 11 is an internal conductive film, 12 is a deflection yoke for deflecting an electron beam horizontally and vertically, and 13 is three electron beams 14 (a center electron beam and two side electron beams). Is an electron gun that fires.

The electron beam B emitted from the electron gun 13 is deflected in two directions, horizontal and vertical, by a deflection yoke 12 attached to a transition portion between the neck portion 2 and the funnel portion 3, and a shadow mask which is a color selection electrode. An image is formed by striking the fluorescent film 4 through the electron beam passage hole 5 of FIG. The illustrated color cathode ray tube is a flat type shadow mask type color cathode ray tube. The panel portion 1 has a substantially flat outer surface and a concave inner surface. The shadow mask 5 is formed by pressing a shadow mask base material into a predetermined curved surface, and is curved according to the inner surface shape of the panel unit 1. Even though the outer surface of the panel portion 1 is substantially flat, the inner surface of the panel portion 1 and the shadow mask 5 are curved because the method of manufacturing the shadow mask 5 by the press molding technique is simple and low cost. Is.

The shadow mask 5 has a substantially rectangular perforated region (main surface) in which a large number of electron beam passage holes are formed, and has different radii of curvature along the major axis, along the minor axis and along the diagonal. . This is to achieve both the flatness of the screen as a color cathode ray tube and the maintenance of the mechanical strength of the shaped shadow mask. The curved surface shape of the illustrated shadow mask 5 is an aspheric surface whose radius of curvature gradually decreases from the center of the main surface toward the periphery along the major axis, along the minor axis and along the diagonal. For example, the radius of curvature Rx along the major axis is between 1450 mm and 1250 mm, the radius of curvature Ry along the minor axis is between 2000 mm and 1300 mm, and the radius of curvature Rd along the diagonal is between 1600 mm and 12 mm.
It varies in the range of 50 mm.

The curvature of this aspherical shadow mask can be defined by the following equation (1) as an equivalent curvature radius Re. Re = (z ² + e ² ) / 2z (1) where e: distance from the center of the main surface of the shadow mask to an arbitrary peripheral position in the direction perpendicular to the tube axis (mm) z : Amount of depression (mm) in the tube axis direction from the center of the main surface of the shadow mask at any of the above peripheral positions. As described above, the feeling of flatness is impaired along the major axis even if the radius of curvature is slightly smaller than the minor axis. However, the equivalent radius of curvature may be 1250 mm or more.

The color cathode ray tube of the present invention can provide a high-definition color cathode ray tube capable of avoiding the deformation of the main surface and displaying a stable image by including the shadow mask structure of the above-mentioned embodiment. Note that the present invention is not limited to the above configuration, and various modifications can be made without departing from the concept of the present invention described in the claims.

[0040]

As described above, according to the typical embodiment of the present invention, it is possible to prevent the local deformation of the main surface of the shadow mask due to the deformation of the mask frame and display a stable image. A high-definition color cathode ray tube can be provided.

[0041]

[Brief description of drawings]

FIG. 1 is a plan view of a mask frame constituting a shadow mask structure according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view taken along the line aa of FIG.

FIG. 3 is a plan view of a mask frame constituting a shadow mask structure for explaining a second embodiment of the present invention.

4 is a partial cross-sectional view taken along the line aa of FIG.

FIG. 5 is a cross-sectional view of a main part of a mask frame forming a shadow mask structure according to a third embodiment of the present invention.

FIG. 6 is a cross-sectional view of a main part of a mask frame which constitutes a shadow mask structure according to a fourth embodiment of the present invention.

FIG. 7 is a sectional view of a main part of a mask frame constituting a shadow mask structure for explaining a fifth embodiment of the present invention.

FIG. 8 is a sectional view of an essential part of a mask frame constituting a shadow mask structure for explaining a sixth embodiment of the present invention.

FIG. 9 is a sectional view of a main part of a mask frame constituting a shadow mask structure for explaining a seventh embodiment of the present invention.

FIG. 10 is a sectional view illustrating an example of the overall configuration of a color cathode ray tube according to the present invention.

FIG. 11 is a perspective view illustrating a configuration example of a shadow mask assembly.

FIG. 12 is an explanatory diagram of a cross-sectional shape of a shadow mask.

FIG. 13 is an explanatory diagram of a modification of the flat mask.

FIG. 14 is an explanatory diagram of a mask frame that has been conventionally used.

FIG. 15 is an explanatory diagram of deformation that occurs in the mask frame.

[Explanation of symbols]

5 ... Shadow mask, 6 ... Mask frame, 6L ... Long side. 6S ... ・ Short side, 6LW ...
.... Sidewalls on long side, 6SW ... Sidewalls on short side, 6L
F ... Long side flange, 6SF ... Short side flange, 6H ... Aperture through which electron beam passes, 6
0 ... Reinforcement material.

Claims (8)

[Claims] 1. A vacuum envelope having a substantially rectangular panel portion having a fluorescent film formed on an inner surface thereof, a neck portion accommodating an electron gun, and a funnel portion connecting the neck portion and the panel portion, and the fluorescent film. A substantially rectangular color selection electrode having a frame-shaped skirt portion that is bent in the neck portion direction from the peripheral edges of the long sides and short sides of the main surface facing each other and having a plurality of electron beam passage holes formed therein; A color cathode ray tube comprising a frame-shaped mask frame for holding the skirt portion of the color selection electrode by welding, wherein the mask frame has a long side that substantially matches the outer shape of the skirt portion of the color selection electrode. A side wall having a short side for welding the skirt portion of the color selection electrode to the fluorescent film side, and a flange bent on the electron gun side of the side wall in a direction substantially parallel to the plane of the color selection electrode. , On the flange Color cathode ray tube characterized by comprising a reinforcing material constant to extend continuously to the short side and the long side. 2. The color cathode ray tube according to claim 1, wherein the mass of the reinforcing material provided on at least the long side is larger at the central portion than at the short side end portions. 3. The color cathode ray tube according to claim 1, wherein the flange has a recess for mounting the reinforcing material. 4. The color cathode ray tube according to claim 1, wherein the flange has a step portion for mounting the reinforcing material. 5. The color cathode ray tube according to claim 1, wherein the flange has an inclined portion for mounting the reinforcing material. 6. The color cathode ray tube according to claim 1, wherein the reinforcing member has a discontinuous central portion on the short side. 7. The color cathode ray tube according to claim 1, wherein the reinforcing material is provided on the flange side of the electron gun. 8. The color cathode ray tube according to claim 7, wherein the reinforcing material is a member for attaching the inner shield.