KR20020040572A - Color cathode ray tube - Google Patents

Abstract

PURPOSE: To realize a press mask having a large radius of curvature by self-correcting doming. CONSTITUTION: As a material to constitute a shadow mask, a single plate body composed of a compound gradient alloy plate wherein an alloy element has a concentration gradient continually decreasing from one face toward the other.

Description

Color Cathode Ray Tube {COLOR CATHODE RAY TUBE}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask type color cathode ray tube, and more particularly, to a highly reliable color cathode ray tube which improves the material strength of a shadow mask, improves etching property and moldability, and reduces thermal deformation.

Background Art In recent years, flat faced flattening of a panel (face panel) that is an image display surface of a color cathode ray tube used in a display device for an information device and a color receiver is rapidly spreading. In particular, in the case of employing a pressure shaping shadow mask in which curved surfaces with holes in the horizontal and vertical directions are used, the panel of this flat face colored cathode ray tube (flat face tube) has an outer surface substantially close to a plane, It has a much larger curvature than the exterior.

One of the technical problems in designing such a flat face tube is shadow mask strength. The shadow mask is molded to have a curvature close to the curvature of the inner surface of the panel. However, since the flat face tube has a smaller curvature of the inner surface of the panel than the round face tube having an inner and outer surface, the curvature of the shadow mask of the flat face tube is inevitably reduced. Therefore, the temperature of the shadow mask is increased by the collision of the electron beam during operation, making it difficult to hold the strength against thermal deformation due to the so-called domming phenomenon of the surface having the shadow mask hole. It is also difficult to maintain physical strength against dropping, impact, or the like of the shadow mask.

As a material for securing the strength of this kind of shadow mask, a cobalt-added invar material in which cobalt is added to a conventional invar material is used.

Aluminum-kilted steels have been used for the shadow mask material, but invar materials have been used with high definition of the image and flat face of the screen. The cobalt-added invar material used for improving the shadow mask strength can secure about 20% of strength compared to a normal invar material, and can suppress deformation of the shadow mask. However, in a shadow mask in which cobalt is added to an invar material, (1) an increase in cost due to high cobalt, (2) a decrease in etching efficiency due to good corrosion resistance of cobalt, (3) a decrease in workability, and (4) magnetic properties There are disadvantages such as degradation.

It is an object of the present invention to provide a flat face type color cathode ray tube with a shadow mask which alleviates the disadvantages of such a conventional shadow mask.

The representative point of this invention for achieving the said objective is the shadow mask material with which a color cathode ray tube is provided, Comprising: An element for alloy is included in a plate member, The said alloy element contained in the said plate member is the one side of the said plate member. It is formed from iron having a concentration gradient continuously decreasing from the side toward the other side. Representatives of the configuration of the present invention are described as follows.

(1) A vacuum casing comprising a panel coated with a plurality of phosphors on an inner surface, a neck containing an electron gun, and a funnel portion for continuous contact between the panel and the neck, the apparatus being installed close to a phosphor coated on the inner surface of the panel. And a shadow mask having a plurality of openings for color selection,

A concentration gradient in which the material constituting the shadow mask is a single plate member formed of an iron material containing an alloying element, and the alloying element continuously decreases from the phosphor side of the single plate member toward the electron gun side. It was set as the composite warp alloy plate which has a.

(2) When the single plate member which is the composite warp alloy plate contains nickel as an alloying element, the content of the nickel in the vicinity of the surface of the phosphor-side surface of the single plate member is 45 wt% or less. The content of the nickel in the vicinity of the surface of the electron gun side surface of the film was 0 wt% or more.

(3) In the case of (2), in which the single plate member that is the composite warp alloy plate contains nickel as an alloying element, the content of nickel in the vicinity of the surface of the phosphor-side surface of the single plate member is 36 wt. It was assumed that the nickel content in the vicinity of the surface of the electron gun side surface of the single plate member was 16 wt% or less.

(4) The color selection opening formed in the shadow mask was a dot, and the entire shadow mask was a shape independence holding type.

(5) The color selection opening hole formed in the shadow mask was formed in a continuous manner in one direction, and a member was formed in which a tension was applied in the extending direction of the opening hole to a member which forms the opening of the occurrence. .

(6) The color selection opening hole formed in the shadow mask has a slot shape having a long axis in one direction, and the entire shadow mask is tensioned in a shape independence holding type or in the long axis direction or the long axis direction and the short axis direction of the slot opening. The structure was added.

In addition, this invention is not limited to the structure demonstrated by each structure mentioned above and the Example mentioned later, A various deformation | transformation is possible within the scope of the technical idea of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross sectional view of principal parts of a shadow mask for explaining a first embodiment of a color cathode ray tube of the present invention.

Fig. 2 is a perspective view of a shadow mask structure provided in the first embodiment of the color cathode ray tube of the present invention.

3 is an explanatory view of an example of a method for producing a composite warp alloy plate which is a material of a shadow mask used in the color cathode ray tube of the present embodiment.

4 is a perspective view for explaining the structure of the composite warp alloy plate obtained in the manufacturing process of FIG.

5A and 5B show concentration distributions of nickel in the composite warp alloy plate shown in FIG.

Fig. 6 is a cross-sectional schematic diagram illustrating an internal stress distribution of a composite warp alloy plate made of a material of a shadow mask used in the color cathode ray tube of the embodiment of the present invention.

7A, 7B and 7C are schematic explanatory diagrams of the images actually observed on the face panel when the shadow mask formed from the Invar material of the comparative example with the present invention is combined with a flat face panel having a large inner curvature.

8A, 8B and 8C are schematic explanatory diagrams of an image actually observed on the face panel when a shadow mask formed into a cylindrical shape is combined with a flat face panel which is only curved in the horizontal direction.

9A, 9B and 9C are schematic explanatory diagrams of an image actually observed on the face panel when the shadow mask formed from the shadow mask material of the embodiment of the present invention is combined with a flat face panel having a small inner curvature.

10 is a schematic sectional view for explaining an example of the overall configuration of a color cathode ray tube of the present invention.

Fig. 11 is a schematic sectional view for explaining still another example of the entire color cathode ray tube configuration of the present invention.

<Description of the symbols for the main parts of the drawings>

1: Panel

2 neck

3 funnel section

4: phosphor

6: shadow mask

6A: 1st Composition Division

6B: Second Composition Division

7: mask frame

8: suspension spring

60: electron beam through hole

61: periphery

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to drawings of an Example.

1 is a schematic cross-sectional view of an essential part of a shadow mask for explaining a first embodiment of a color cathode ray tube of the present invention, and FIG. 2 is a perspective view of a shadow mask structure provided in the first embodiment of a color cathode ray tube of the present invention.

As shown in Fig. 2, the shadow mask 6 has a periphery that is formed in a curved surface corresponding to the inner surface curvature of the face panel in which the hole AR, which is a main part thereof, will be described later. 61 is welded to the mask frame 7 to form a shadow mask structure. Moreover, the suspension frame 8 is attached to the mask frame 7 for fitting to the stud pin implanted in the inner wall of the skirt part of a face panel (this structure is mentioned later).

The shadow mask material constituting the shadow mask 6 of the present embodiment is based on a steel material containing nickel as an alloying element, and nickel on the fluorescent surface side, which is one side on the side indicated in the Z-axis (tube axis: arrow Z) direction of FIG. It consists of a single plate member which is a composite inclined alloy plate having a first composition portion 6A having a maximum content of 6A and a second composition portion 6B having a minimum content of nickel at an electron gun side which is the other surface on the opposite side to the one surface. do.

Nickel content continuously decreases between a 1st composition part and a 2nd composition part. Thus, the single plate member which continuously reduces an alloying element from one surface side to the other surface side of a single plate member is called a composite inclined alloy plate here.

In Fig. 1, the nickel element as an alloying element of the composite warp alloy plate is schematically represented by ×, and the difference in the nickel content on the fluorescent surface side and the electron gun side in the cross section of the composite warp alloy plate constituting the shadow mask 6 is shown. Is represented by the density of x.

The composite inclined alloy plate may be referred to as a single plate member having a continuous alloy region in the middle region of the first metal plate of the first composition part 6A and the second metal plate of the second composition part 6B. However, it is different from the so-called clad plate member which attached two different metal plates of the prior art. In the case of the clad plate member, the content of the alloying element as shown in Fig. 1 does not have an inclination.

Iron and a nickel alloy plate and the 2nd composition part 6B can be used as the iron plate, and the nickel content can be made 0 to the 2nd composition part 6B. Alternatively, the first composition portion 6A may have a high nickel content, the second composition portion 6B may have a low nickel content, specifically, the first composition portion 6A may have an invar material (a nickel content of about 36 wt%). Nickel iron alloy), and the second composition part 6B is made of stainless steel containing about 16 wt% nickel, or the first composition part 6A is made of stainless steel containing about 17 wt% nickel. The second composition 6B can also be made of stainless steel containing about 16 wt% nickel.

The first composition 6A may also be a permalloy (nickel and iron alloy containing about 43 wt% nickel). In consideration of the magnetic properties and the cost of the material, the nickel content is preferably controlled to 45 wt% or less.

The shadow mask 6 of this embodiment is formed by etching an electron beam through hole 60, which is an open hole for color selection, in the composite warp alloy plate. The electron beam passage hole 60 has a dot shape having a large diameter on the fluorescent surface side and a small diameter on the electron gun side. The shadow mask in which the electron beam passage hole 60 is formed is formed into a predetermined shadow mask shape by pressing, welded to the mask frame shown in Fig. 2, and attached with a suspension spring 8 to form a shadow mask structure.

In addition, in the embodiment shown in Fig. 1, the shape of the electron beam through hole 60 is made into a substantially circular dot shape. However, the present invention is not limited thereto, and the shape of the electron beam passing hole is a slot having a substantially rectangular slot shape having a long axis in one direction (usually a vertical deflection direction), or a slit continuous in one direction (usually a vertical deflection direction). Even if it is made into a mold | type (cranium type), it can carry out similarly.

By assembling a color cathode ray tube using the shadow mask of this embodiment and the shadow mask of the present embodiment using the composite warp alloy plate as a shadow mask material, there is a great advantage that cannot be obtained from the following conventional art.

-Since it does not contain expensive metal elements, such as cobalt, or can employ | adopt the material which does not contain nickel in a 2nd composition part, it becomes low in material cost compared with the conventional Invar material.

By not containing good cobalt corrosion resistance, the etching rate in the formation of the electron beam through hole is improved, and the production cost of the shadow mask is reduced.

The electron beam through hole can be etched into the most suitable shape by the concentration ratio in the first and second composition parts of the alloy element of the composite warp alloy plate, and an electron beam through hole having a uniform cross-sectional shape can be formed.

• Since the distribution of the stress generated during the compression molding of the composite warp alloy plate is gradually changed inside the alloy plate, no sudden load is applied to the alloy plate. Therefore, the strength of the composite inclined alloy plate material is 5 to 10 times that of the conventional invar material.

Since the nickel content can be reduced as a whole, the magnetic properties are improved by increasing the permeability and decreasing the coercive force, and the shielding effect of the geomagnetism is improved.

Since the strength of the shadow mask material made of a thin plate is greatly increased, the occurrence of local doming (thermal expansion of the mask curved surface) due to the collision of the electron beam to the surface with the mask hole can be reduced.

3 is an explanatory view of an example of a method for producing a composite warp alloy plate that is a material of a shadow mask used in the color cathode ray tube of the present embodiment. Here, the case where the 1st composition part 6A is made into the invar material (nickel iron alloy containing nickel about 36 wt%), and the 2nd composition part 6B is made into stainless steel containing about 16 wt% nickel is demonstrated. do.

In Fig. 3, 6AA shows a melt of Invar material, 6BA shows a melt of stainless steel containing about 16 wt% of nickel, and these are drawn out as hot waves by the rolling rollers PR1 and PR1 ', and a few steps of the rolling rollers PR2. Hot rolling is carried out in the form of) to be combined.

In this hot rolling step, an alloy layer is formed between the invar material 6A and the stainless steel material 6B containing about 16 wt% nickel, and the nickel content is directed from one side to the other side of the single plate member. It results in a composite warp alloy plate having a continuously decreasing concentration gradient.

Thereafter, cold rolling is performed with the rolling roller PR3 at a predetermined stage to obtain a plate member having a predetermined thickness as a shadow mask material.

FIG. 4 is a perspective view illustrating the structure of the alloy warp alloy plate obtained by the manufacturing process of FIG. 3, wherein the nickel content changes in an oblique manner on one face side and the other face side in the same cross section as in FIG. It shows the state that there is. In addition, the element concentration of nickel is shown by the density of x similarly to FIG.

5A and 5B show a concentration distribution of nickel in the composite warp alloy plate shown in FIG. 4, FIG. 5A shows a distribution curve of nickel concentration, and FIG. 5B shows a cross-sectional schematic diagram of the composite warp alloy plate for explaining FIG. 5A. to be. As shown in Fig. 5A, on one side A side of the composite warp alloy plate, nickel is 36 wt% of Invar itself, and on the other side B side, nickel is stainless steel itself containing about 16 wt% nickel. Phosphorus is 16 wt%. And, between the surface A side and the surface B side, the nickel content gradually decreases from 36 wt% to 16 wt%. Moreover, the form of the distribution curve of nickel concentration shown in FIG. 5A has a thick treatment material at the time of hot rolling and cold rolling, and changes with temperature, rolling speed, and other conditions.

6 is a schematic cross-sectional view for explaining an internal stress distribution of the composite warp alloy plate of the present embodiment. For example, when a pressure as shown by arrow P of FIG. 6 is applied to the composite warp plate manufactured above, the tensile stress shown by arrow SR occurs on the surface A side toward the outside from the pressure application point. On the surface B side, as shown by the arrow PR, a compressive stress in the direction compressing inwardly occurs. The tensile stress SR and the compressive stress PR are continuously decreased in the region between the plane A and the plane B according to the distribution of the nickel element in Fig. 5A, and become approximately zero in the middle. Thus, in the cross section of a plate, it changes gradually from tensile stress SR to compressive stress PR, and distribution of each stress SR and PR becomes substantially symmetrical. Therefore, this composite inclined alloy plate has a function of absorbing external impact.

For this reason, when this composite inclined alloy plate is used as a shadow mask material, it is difficult to shift the relative position of the surface A and the surface B by press molding after electron beam passage hole formation, and it is hard to cause distortion in the shape of the said electron beam passage hole.

When this composite warp alloy plate is used as a shadow mask material, the curvature can be made small and the curved surface of the mask can be easily formed, and the shadow mask of a substantially small curvature can be formed on the inner surface of the face panel close to the plane.

Moreover, although it is preferable to form in the whole shadow mask about the area | region which has the density | concentration gradient from one surface to the other surface in the single plate member of the said alloy element, you may provide it partially according to the use of a color cathode ray tube. .

For example, according to the mechanical properties of the shadow mask or the like against the external impact, or the thermal properties of the electron beam collision, etc., the area AR having the holes of the shadow mask 6 shown in Fig. 2, and the periphery 61 (skirt portion) The concentration gradient region of the alloying element may be provided by selecting from an outer edge portion (region without hole) surrounding the region AR with holes.

Fig. 7A is a shadow mask molded from the Invar material of the comparative example of the present invention, Fig. 7B is a flat face panel having a large curvature of the inner surface, and Fig. 7C is actually observed on the face panel when the shadow mask is combined with the face panel. It is a typical explanatory drawing of the image which becomes.

FIG. 7A shows an area with holes in a shadow mask that are press-molded at an average radius of curvature Rx in the horizontal (along axis) direction of 1600 mm and an average radius of curvature Ry in the vertical (along axis) direction of 1300 mm; Fig. 7B is a region where the outer surface is substantially flat and there is a hole of the face panel having a large curvature on the inner surface, and the thickness Tr in the tubular direction in the corner portion is considerably larger than the thickness Tc in the tubular direction in the center portion (Tr >> Tc). . In this case, if the thickness difference (Tr-Tc) between the panel effective screen corner (diagonal end) and the center is made into diagonal wedge amount Wr, this diagonal wedge amount Wr and panel center thickness Tc The ratio (Wr / Tc) to is 1.2 or more.

In this shadow mask by compression molding, as shown in Fig. 7C, the screen looks concave as it moves from the center of the panel to the periphery. As the viewing direction, the center of the screen is convex, and an image with little flatness is observed.

FIG. 8A shows a shadow mask molded into a cylindrical surface shape, FIG. 8B shows a flat face panel which is curved only in the horizontal direction from the inner surface, and FIG. 8C shows actually observed on the face panel when a shadow mask is combined with the face panel. It is a schematic diagram of an image.

Fig. 8A shows a shadow mask (so-called color-of-currency) whose average radius of curvature Rx in the horizontal (long axis) direction is 2000 mm and the radius of curvature Ry in the vertical (along axis) direction is infinite (∞). 8B is an effective screen area of the face panel having an outer surface that is substantially flat and having curvature only in the horizontal direction of the inner surface, wherein the thickness Tr in the tube axis direction of the corner portion is the thickness in the tube axis direction of the center portion. Significantly greater than (Tc) (Tr >> Tc). In this case, the ratio (Wr / Tc) of the diagonal wedge amount Wr to the panel center thickness Tc is 1.0 or more.

The shadow mask formed in this cylindrical surface shape is a so-called tension mask which is tensioned in the vertical direction as shown in Fig. 8A, and cannot have curvature in the tension direction. Therefore, the radius of curvature is almost infinity with respect to the tension direction of the shadow mask of the inner surface of the face panel, that is, the vertical direction is approximately straight.

For this reason, by the refraction of the glass material which comprises a face panel, as shown in FIG. 8C, the center part of a face panel curves in concave shape in a vertical direction, and is observed.

Fig. 9A is a shadow mask molded from the shadow mask material of this embodiment, Fig. 9B is a flat face panel having a small inner curvature, and Fig. 9C is an image actually observed on the face panel when the shadow mask is combined with the face panel. A schematic explanatory diagram of.

9A shows an area with holes in the shadow mask which are press-molded with an average radius of curvature Rx in the horizontal (along axis) direction of 5000 mm and an average radius of curvature Ry in the vertical (along axis) direction of 4000 mm, Fig. 9B is a screen area with a hole in the face panel having a substantially flat outer surface and a curvature of the inner surface smaller than Fig. 7B, wherein the thickness Tr in the tube axis direction of the corner portion is slightly larger than the thickness Tc in the tube axis direction of the center portion (Tr). > Tc).

In this embodiment, the design of the cathode ray tube with the conditions for appearing optically flat becomes possible as a ratio. That is, the shadow mask of this embodiment has a strong physical strength, and since the material has a bimetallic action and the shadow mask itself has a dominant correction function, the shadow mask has an average radius of curvature Rx along its horizontal (long axis) direction. ) And the average curvature radius Ry in the vertical (along the short axis) directions can be compressed to a shape close to one plane with 3000 mm or more, respectively.

Therefore, the difference (corner wedge amount Wr) between the thickness Tr of the corner portion and the thickness Tc of the center portion of the face panel shown in Fig. 9B can be made small, and the optical distance ( The optical distance LcTc between LrTr and the thickness Tc of the center portion becomes approximately equal. And the image of the observed image can also be made substantially flat as shown in FIG. 9C. In this case, the ratio (Wr / Tc) between the corner wedge amount Wr and the panel center thickness Tc is set to 0.8 or less.

In addition, since the thickness of the periphery of the face panel can be reduced, high brightness of the image is facilitated and luminance uniformity over the entire screen is improved.

In addition, when the shadow mask material of this embodiment is applied to the tension mask of Fig. 8A, the curvature can be formed by increasing the curvature radius in the horizontal direction, so that the curvature radius in the horizontal direction on the inner face panel can be also large. As shown in Fig. 9B, it is possible to reduce the thickness of the face panel periphery to improve the luminance characteristics of the display screen.

In addition, since the tension mask shown in Fig. 8A has a door-like pattern in which the color selection opening holes are continuous in one direction, the grid-shaped grid connecting the door-shaped color selection opening holes may vibrate by an impact or the like. . Therefore, in order to prevent this vibration, a thin wire along the major axis (X axis) is attached to the outer side of the tension mask curved surface. However, when the composite warp alloy material according to the present embodiment is applied to the tension mask, the material strength is considerably stronger than that of the conventional Invar material. Therefore, the vibration preventing wire may not be mounted on purpose.

As described above, since the press mask can be made close to the plane, the face panel can also be suitably designed with its inner surface close to the plane. Then, the reflected light from the inner surface of the panel due to the difference in thickness between the center portion and the peripheral portion of the panel of FIG. 7B can be reduced without the need of antireflection means such as an inner surface filter film. Further, by making the inner surface of the panel close to the plane, the periphery of the face panel can also be made thin, so that the weight of the panel and the cost of the color cathode ray tube can be reduced.

In addition, even for a color cathode ray tube using a so-called tension mask which is tensioned in one direction (usually a vertical direction), the radius of curvature of the inner surface of the face panel orthogonal to the one direction (generally the horizontal direction) of the applied face panel is greatly increased. Since the thickness of the peripheral part of the panel can be reduced, it is possible to suppress the reflected light from the panel inner surface, reduce the weight of the panel, and reduce the cost of the color cathode ray tube.

Further, when the average radius of curvature Ry along the short axis (Y axis) of the press mask of this embodiment of Fig. 9A is 10000 mm or more, the inner surface of the press mask of this embodiment is shown in Fig. 8B instead of the tension mask. This cylindrical surface type can be used for a face panel having a large inner radius of curvature in the long axis (X-axis) direction.

In addition, since the shadow mask material of the present embodiment is the above-described composite warp alloy plate, and has a bimetallic action itself, the shadow mask material has a bimetallic action, so that the design can be appropriately corrected even for partial doming of the mask curved surface, for example, local doming by window pattern display. Becomes possible.

Conventional shadow mask structures have coped with suspension springs attached to the mask frame to compensate for the thermal expansion of the mask frame due to the doming of the curved surface of the mask by electron beam collision and the increase in ambient temperature. In this embodiment, the shadow mask itself can perform the dope correction by the bimetal action of the shadow mask itself. For this reason, the design of the suspension spring may be specified for the thermal expansion correction of the mask frame, and the design margin of the entire shadow mask structure is improved. In addition, it is possible to provide a high-brightness and high-definition color cathode ray tube capable of operating in a high current region that is hardly dope corrected in the related art.

In addition, in the above embodiment, a nickel iron alloy material containing iron as a base material and containing nickel as an alloying element has been described. However, the present invention is not limited to this, and is not limited to chromium or an iron alloy material containing nickel and chromium. For example, it can carry out similarly using the iron alloy containing various stainless steel and other alloy elements.

In addition, in the said Example, content of the same alloy element (for example, nickel) was changed into the 1st composition part and the 2nd composition part. However, the present invention is not limited thereto, and the alloy composition is different in the first composition portion and the second composition portion, and the content of the alloying element in the first composition portion is gradually decreased from one surface of the plate member to the other surface. It is good also as a structure which content of the alloying element of 2 composition part gradually decreases toward the one surface from the other surface of a board member. For example, even if the alloy element of a 1st composition part is nickel and the alloy element of a 2nd composition part is silicon, the effect similar to the said Example is exhibited.

It is a schematic cross section explaining an example of the whole structure of the color cathode ray tube of this invention. This color cathode ray tube is a panel (face panel) 1 having a plurality of phosphors coated on its inner surface, a neck 2 containing the electron gun 11, and a panel 1 and a neck 2 continuously contacting each other. It has a vacuum casing which consists of an approximately funnel-shaped funnel part 3.

The phosphor 4 of three colors is apply | coated to the inner surface of the panel 1, and the shadow mask 6 which has many opening holes for color selection in proximity to this phosphor 4 is provided. Reference numeral 5 denotes a shadow mask structure, and the shadow mask 6 constituting the shadow mask structure has a plurality of electron beam through holes which have been etched to the above-described composite warp alloy plate, and is fixed by welding to the mask frame 7. .

The shadow mask 6 is curved with a large radius of curvature in both the horizontal and vertical directions. Z-axis (tube axis), the axis orthogonal to the minor axis (Y axis: direction of arrow Y in the drawing) of the shadow mask 6 that is orthogonal to and passes through the center Om of the hole area. If the depression amount in the Z-axis direction from the center Om of the holed area at any point (x, y) in the holed area of the mask 6 is Zm, the shadow mask 6 The curved shape of is generally defined by the following equation.

Zm = A1x ² + A2x ⁴ + A3y ² + A4y ⁴ + A5x ² y ² + A6x ² y ⁴ + A7x ⁴ y ² + A8x ⁴ y ⁴ (A1 to A8 are coefficients)

The desired curved shape can be obtained by determining the coefficients A1 to A8 of this equation.

In addition, although the said curved shape was defined taking the shadow mask 6 as an example, the effective screen area of the panel 1 can also be defined similarly.

The curved surface according to the above formula is often an aspheric shape, the radius of curvature is different depending on the arbitrary position of the curved surface. Therefore, the curvature (curvature radius) of the shadow mask can be defined as the average curvature radius described in Fig. 9A as follows.

Ry = (Zv ² + V ² ) / 2Zv

However, Ry is the average radius of curvature (mm) along the minor axis (Y axis) of the hole area, V is the distance orthogonal to the Z axis from the center (Om) of the hole area to the end along the Y axis. (mm), Zv represents the amount of depression (mm) in the Z-axis direction between the center (Om) of the region where the hole is located and the end along the Y-axis.

In addition, the mean radius of curvature is defined as an example along the short axis (Y axis) of the region having the shadow mask hole, but may be defined along the long axis (X axis) or diagonally in the same manner. The effective screen area of the panel 1 can also be defined in the same manner.

The magnetic shield 10 is fixed to the electron gun side of the mask frame 7, and is suspended by the stud pins 9 placed on the inner wall of the skirt of the panel 1 via the suspension spring 8.

The deflection yoke 13 is externally mounted on the neck side of the funnel, and the three electron beams B emitted from the electron gun 11 are deflected in the horizontal direction and the vertical direction (arrow Y direction in the drawing), and the fluorescent surface 4 An image is formed on the image. In addition, the code | symbol 12 is self-correction apparatuses, such as purity correction and convergence correction, and the code | symbol 14 is a width band.

With the color cathode ray tube constructed in this way, it is possible to obtain a high brightness and high definition color image display in which color variations due to the shadowing of the shadow mask curved surface are suppressed.

FIG. 11 is a schematic sectional view for explaining another example of the overall configuration of the color cathode ray tube of the present invention, and the same reference numerals as those in FIG. 10 correspond to the same functional parts. This color cathode ray tube has a substantially funnel-shaped panel in which a plurality of phosphors are coated on an inner surface thereof, a neck 2 accommodating the electron gun 11, and a continuous contact between the panel 1 and the neck 2. Although it has the vacuum casing which consists of the funnel part 3, the inner surface of the panel 1 has a large curvature radius in a horizontal direction, and the curvature radius of a vertical direction (arrow Y direction of a figure) is infinite.

The shadow mask 6, which is a color selection electrode provided in this color cathode ray tube, has a large radius of curvature in the horizontal direction, and the vertical direction has a radius of curvature or infinitely larger than the horizontal direction.

The shadow mask 6 is tensioned and fixed to the mask frame 7. However, you may fix to a mask frame in the state hold | maintained magnetic shape without applying tension. Even when it is fixed to the mask frame in the state of holding the magnetic shape without applying tension, the domming is corrected by the bimetal function of the shadow mask, and color deviation and the like are reduced.

With the color cathode ray tube constructed in this way, it is possible to obtain high brightness and high definition color image display in which color variation due to doming is suppressed.

As described above, according to the representative configuration of the present invention, since the material of the shadow mask, which is the color selection electrode, does not contain expensive metal elements such as cobalt, or by adopting a material that does not contain nickel or the like on one surface side, In comparison with the conventional Invar materials, the material cost is reduced, the etching property in the formation of the electron beam through-holes is improved, and the electron beam through-holes can be etched into a suitable shape by the ratio of the alloy region of the composite warp alloy plate. It is possible to form an electron beam passing hole having a uniform cross-sectional shape.

In addition, since the nickel content can be reduced as a whole, the magnetic properties are improved, the shielding effect of the geomagnetism is improved, the strength of the thin plate as a shadow mask material is greatly increased, and the occurrence of local doming can also be reduced. As a result, it is possible to provide a color cathode ray tube with high brightness and high definition.

Claims (20)

A panel coated with a plurality of phosphors on the inner surface, a neck containing an electron gun, and a vacuum casing comprising a funnel portion for continuous contact between the panel and the neck; A shadow mask having a holed area consisting of opening holes for color selection of The material constituting the shadow mask is a plate member formed of an iron material containing an alloying element, and the compound gradient alloy having a concentration gradient in which the element for alloying continuously decreases from the phosphor side to the electron gun side of the plate member. Color cathode ray tube, characterized in that the plate. The color cathode ray tube according to claim 1, wherein the holed area of the shadow mask is curved along the long axis, and the average radius of curvature is 3000 mm or more. The color cathode ray tube according to claim 1, wherein the alloying element is nickel. The content of the nickel in the vicinity of the surface of the phosphor-side surface of the plate member is 45 wt% or less, and the content of the nickel in the vicinity of the surface of the electron gun side surface of the plate member is 0 wt% or more. Color cathode ray tube, characterized in that. The nickel content in the vicinity of the surface of the phosphor side of the plate member is 36 wt% or less, and the nickel content in the vicinity of the surface of the electron gun side surface of the plate member is 16 wt% or more. Color cathode ray tube, characterized in that. The color cathode ray tube according to claim 1, wherein the alloying element is chromium. The color cathode ray tube according to claim 1, wherein the alloying elements are nickel and chromium. The color cathode ray tube according to claim 1, wherein the color selection opening formed in said shadow mask is dot-shaped. The color cathode ray tube according to claim 1, wherein the color selection opening formed in the shadow mask is a continuous type in one direction. The color cathode ray tube according to claim 1, wherein the color selection opening formed in said shadow mask is a slot type having a long axis in one direction. It has a panel coated with a plurality of phosphors on the inner surface, a neck containing an electron gun, and a vacuum casing consisting of a funnel portion for continuous contact between the panel and the neck, and are installed in close proximity to the phosphor coated on the inner surface of the panel. A shadow mask having a holed area consisting of opening holes for color selection of The material constituting the shadow mask is a single plate member formed of iron containing an alloying element, and the content of the alloying element contained in the single plate member is smaller in the electron gun side than the phosphor side of the single plate member. Color cathode ray tube characterized by the above-mentioned. 12. The color cathode ray tube according to claim 11, wherein the holed area of the shadow mask is curved along the long axis, and the average radius of curvature is 3000 mm or more. The color cathode ray tube according to claim 11, wherein the alloying element is nickel. The content of the nickel in the vicinity of the surface of the phosphor-side surface of the single plate member is 45 wt% or less, and the content of the nickel in the vicinity of the surface of the electron gun side surface of the single plate member is 0 wt%. The color cathode ray tube characterized by the above. The nickel content in the vicinity of the surface of the phosphor-side surface of the single plate member is 36 wt% or less, and the nickel content in the vicinity of the surface of the electron gun side surface of the single plate member is 16 wt. Color cathode ray tube, characterized in that more than%. The color cathode ray tube according to claim 11, wherein the alloying element is chromium. The color cathode ray tube according to claim 11, wherein the alloying elements are nickel and chromium. A panel coated with a plurality of phosphors on the inner surface, a neck containing an electron gun, and a vacuum casing comprising a funnel portion for continuous contact between the panel and the neck; A shadow mask having an opening for color selection of The material constituting the shadow mask is a single plate member formed of iron containing an alloying element, and the alloying element included in the single plate member is different from one side of the single plate member. Colored cathode ray tube. 19. The color cathode ray tube according to claim 18, wherein one side of the single plate member is the phosphor side, and the other side of the single plate member is the electron gun side. 19. The color cathode ray tube according to claim 18, wherein the alloying element on one side of the single plate member is nickel and the alloying element on the other side of the single plate member is silicon.