JP3556243B2 - Color picture tube - Google Patents

Description

の場合、
【数２】

となり、
【数３】

の場合、
【数４】

となり、ｒｆ は、
【数５】

となる。
その一例について示すと、
Ｒ１＝１６０７ｍｍ
Ｒ２＝１４１７ｍｍ
Ｓ＝１７．９ｍｍ
である。
【００２４】
一方、有効面１０の内面は、下記数６で表される形状に形成されている。
【数６】

なお、Ａ_４ｉ＋ｊは係数であり、座標の中心（Ｘ＝０、Ｙ＝０）である有効領域の中心では、
Ｚ＝０
であるため、
Ａ_０ ＝０
であり、Ａ_１ 〜Ａ_１５は、それぞれ表１に示す値となる。
【表１】

【００２５】
一例として、図４に有効面の長軸（Ｘ軸）に沿った外面および内面の形状を、図５に有効面の短軸（Ｙ軸）に沿った外面および内面の形状を、図６に有効面の対角軸（Ｄ軸）に沿った外面および内面の形状を、それぞれ実線２６Ｘ ，２６Ｙ ，２６Ｄ を外面形状、破線２７Ｘ ，２７Ｙ ，２７Ｄ を内面形状として示す。
【００２６】
パネル１２の有効面１０を上記のように構成すると、その有効面１０は、図７に示す肉厚分布になる。すなわち、長軸上の肉厚分布は曲線２８Ｘ 、短軸上の肉厚分布は曲線２８Ｙ 、対角軸（Ｄ軸）上の肉厚分布は曲線２８Ｄ となる。その結果、パネル１２の有効面１０の中心Ｏから同一距離における長軸上の点Ｍ１ での肉厚Ｈ１ と対角軸上の点Ｍ２ での肉厚Ｈ２ との差は、図８に示す曲線２９のようになり、また短軸上の点Ｍ３ での肉厚Ｈ３ と対角軸上の点Ｍ２ での肉厚Ｈ２ の差は、曲線３０のようになる。つまり、パネル１２の長軸上の点Ｍ１ と同一距離における短軸上の点Ｍ３ での肉厚Ｈ３ と対角軸上の点Ｍ２ での肉厚Ｈ２ との差は、同一距離における対角軸上の点Ｍ２ での肉厚Ｈ２ と長軸上の点Ｍ１ での肉厚Ｈ１ との差よりも小さく、この関係がパネル１２の有効面１０の中心Ｏから距離の大きい領域、すなわちパネル１２の有効面１０の中心Ｏから長軸方向端部までの距離の１／２以上の領域おいて小さく、数７の関係となっている。
【数７】

これに対して、従来のパネルの有効面の肉厚分布は、図９に長軸上の肉厚分布を曲線３２Ｘ 、短軸上の肉厚分布を曲線３２Ｙ 、対角軸上の肉厚分布を曲線３２Ｄ で示すようになっており、同一距離における長軸上の肉厚と対角軸上の肉厚との差は、同一距離における対角軸上の肉厚と短軸上の肉厚との差よりも小さくなっている。これは、対角軸が短軸よりも長軸に接近しているためである。しかし上記実施例に係るパネル１２の有効面１０の肉厚分布は、このように対角軸が短軸よりも長軸に接近していても、上記従来のパネルの有効面の肉厚分布と逆の関係になっている。
【００２７】
パネル１２の有効面１０の肉厚分布を上記のようにすると、パネル１２の有効面１０の外面を平坦にして、外面から映込みが自然に見える違和感のない１つあるいは２つの球面からなる形状にしても、有効面１０の長軸方向の中間部における内面の短軸に平行な方向の断面（Ｙ−Ｚ平行断面）の曲率半径を従来のパネルのそれよりも小さくすることができる。その結果、シャドウマスク１６の同方向の曲率半径も小さくでき、シャドウマスク１６の局部的な熱変形が最も生じやすい長軸方向中間部における色純度の劣化を有効に補正することができる。
【００２８】
一例として、２３インチ１１０度偏向管について、有効面の肉厚分布を図７に示した曲線２８Ｘ 、２８Ｙ 、２８Ｄ にしたことにより、それに対応して形成されるシャドウマスクの熱変形によるミスランディングを約１５％改善することができた。
【００２９】
なお、有効面の肉厚分布を図７に示した曲線２８Ｘ 、２８Ｙ 、２８Ｄ のようにしても、パネルの強度は、ほとんど変わらない。
【００３０】
【発明の効果】
パネルの有効面の中心から同一距離における短軸上のパネルの肉厚、対角軸上のパネルの肉厚および長軸上の肉厚の関係を、短軸上の肉厚＞対角軸上の肉厚＞長軸上の肉厚とし、パネルの実質的に矩形状の有効面の中心から同一距離における短軸上のパネルの肉厚と対角軸上のパネルの肉厚との差が同一距離における対角軸上のパネルの肉厚と長軸上のパネルの肉厚との差よりも少なくとも有効面の中心から長軸上端部までの距離の１／２以上の領域において小さくし、かつパネルの有効面の外面は球面からなるほぼ平坦な面とすると、パネルやシャドウマスクの形状を大幅に変更することなく、その曲面形状を部分的に変更するのみで、パネル外面から映込みが自然に見える違和感のない球面からなるほぼ平坦なパネルに対しても、シャドウマスクの局部的な熱変形に起因する色純度の劣化を有効に補正することができる。
【図面の簡単な説明】
【図１】この発明の一実施例であるカラー受像管のパネルの有効面の形状を説明するための図である。
【図２】この発明の一実施例であるカラー受像管の構成を示す図である。
【図３】上記パネルの有効面に形成される蛍光体スクリーンの説明図である。
【図４】上記パネルの有効面の長軸に沿った外面および内面の形状を示す図である。
【図５】上記パネルの有効面の短軸に沿った外面および内面の形状を示す図である。
【図６】上記パネルの有効面の対角軸に沿った外面および内面の形状を示す図である。
【図７】上記パネルの有効面の長軸、対角軸、短軸上の肉厚分布を示す図である。
【図８】上記パネルの有効面の長軸上の肉厚と対角軸上の肉厚との差および対角軸上の肉厚と短軸上の肉厚との差を示す図である。
【図９】従来のカラー受像管のパネルの有効面の長軸、短軸、対角軸上の肉厚分布を示す図である。
【図１０】従来のカラー受像管のシャドウマスクの局部的な熱変形に起因する色純度の劣化を説明するための図である。
【図１１】図１１（ａ）および（ｂ）はそれぞれ蛍光体スクリーン上に描かれる画像パターンとミスランディングとの関係を説明するための図である。
【符号の説明】
１０…有効面
１２…パネル
１４…蛍光体スクリーン
１５Ｂ ，１５Ｇ ，１５Ｒ …３色蛍光体層
１６…シャドウマスク
１７…マスク本体
１８…マスクフレーム
２２Ｂ ，２２Ｇ ，２２Ｒ …３電子ビーム
２３…電子銃[0001]
[Industrial applications]
The present invention relates to a color picture tube of a shadow mask type, and more particularly to a color picture tube having a panel for preventing deterioration of an image due to thermal deformation of a shadow mask.
[0002]
[Prior art]
In general, a shadow mask type color picture tube has a panel having a skirt portion provided on the outer periphery of a substantially rectangular effective surface having a curved surface, and a funnel-shaped funnel joined to the skirt portion of the panel. A phosphor screen including a three-color phosphor layer that emits blue, green, and red light is formed on an inner surface of an effective surface of the panel, and a large number of phosphor screens are provided inside and facing the phosphor screen. A shadow mask in which a mask body having an electron beam passage hole has a curved surface is disposed. On the other hand, an electron gun that emits three electron beams is disposed in the neck of the funnel. The three electron beams emitted from the electron gun are deflected by a magnetic field generated by a deflection yoke mounted outside the funnel, and the phosphor screen is horizontally and vertically scanned through a shadow mask, thereby forming a color image. It is formed in a structure for displaying.
[0003]
In this color picture tube, in order to display a color image with good color purity on the phosphor screen, three electron beams incident on the phosphor screen through the respective electron beam passage holes of the shadow mask correspond respectively. It is necessary to correctly arrange the three-color phosphor layer and the shadow mask in a predetermined matching relationship so as to land properly on the three-color phosphor layer. For this purpose, it is particularly important to set the distance (q value) between the inner surface of the panel and the shadow mask as designed.
[0004]
However, even if the three-color phosphor layer and the shadow mask are arranged in a predetermined matching relationship, the color picture tube still deteriorates in color purity due to thermal deformation of the shadow mask. That is, in general, the area occupied by the electron beam passage holes in the shadow mask is not more than 1/3 of the entire mask body, and most of the electron beam collides with the shadow mask and heats it. In a normal mask body made of a low-carbon steel sheet containing iron as a main component, the mask expands thermally by heating and causes so-called doming that swells in the direction of the phosphor screen. As a result, the q value changes, the landing position of the electron beam on the three-color phosphor layer changes, and the color purity deteriorates.
[0005]
The change (mislanding) of the landing position of the electron beam with respect to the three-color phosphor layer due to the thermal expansion of the shadow mask differs depending on the image pattern drawn on the phosphor screen and the duration of the image pattern.
[0006]
That is, when an image is drawn on the phosphor screen for a long time, in this case, the shadow mask has a large heat capacity attached not only to the mask body having a large number of electron beam passage holes but also to the periphery of the mask body. Heated to the mask frame. However, mislanding caused by such heating is effectively corrected by attaching an elastic support for supporting the shadow mask to the mask frame via a bimetal as disclosed in Japanese Patent Publication No. 44-3547. Can be. On the other hand, as a mislanding occurring in a short time, there is a local mislanding occurring when a locally high-luminance image is drawn, and a local mislanding occurring when such a locally high-luminance image is drawn. Such a mislanding cannot be corrected by the correction means using the bimetal.
[0007]
That is, as shown in FIG. 10, when a high-luminance image is locally drawn on the phosphor screen 1 by the high-current beam 2, the collision of the high-current beam 2 causes the mask main body 3 as shown by a broken line. Local doming occurs. In this doming portion 4, the electron beam passage hole 5 changes from the position 6a to the position 6b, and when the electron beam 2 is properly landed on the three-color phosphor layer 7 through the electron beam passage hole 5 at the position 6a, The electron beam 2 passing through the electron beam passage hole changed to the position 6b does not land properly on the three-color phosphor layer 7 . However, such a mislanding due to local doming cannot be corrected by the correcting means using bimetal.
[0008]
As shown in FIGS. 11A and 11B, a rectangular frame pattern 9 is generated by a signal generator and the shape, size, and position of the rectangular frame pattern 9 are changed. As a result of examining the relationship with the mislanding, as shown in FIG. 3A, the mislanding caused when the large current beam pattern 10a is drawn over almost the entire surface of the phosphor screen 1 is relatively small. . However, as shown in FIG. 3B, when the large current beam pattern 10b is elongated in the vertical direction, the large current beam pattern 10b is slightly shifted from the peripheral portion of the phosphor screen 1 in the horizontal direction (X-axis direction) to the central portion. It has been found that the mislanding becomes the largest when it is more unevenly distributed.
[0009]
The relationship between the large current beam patterns 10a and 10b and mislanding can be explained as follows.
[0010]
That is, since a television receiver is generally designed so as not to exceed a certain value which is an average anode current of a picture tube, a large pattern such as a large current beam pattern 10a shown in FIG. The current flowing per unit area of the shadow mask is smaller than in the case of a small pattern such as the large current beam pattern 10b shown in FIG. Therefore, the temperature rise of the shadow mask is small. Even if a small pattern such as the large current beam pattern 10b shown in FIG. 11B is located at the center of the phosphor screen 1, mislanding is unlikely to occur even if the shadow mask is thermally deformed. The degree to which thermal deformation of the shadow mask appears on the screen as mislanding increases from the central portion of the phosphor screen 1 to the peripheral portion in the horizontal direction. However, near the periphery of the phosphor screen 1 in the horizontal direction, since the mask frame is attached to the periphery of the mask body, the deformation is small. As a result, the mislanding is maximized slightly in the central part rather than in the peripheral part in the horizontal direction.
[0011]
Particularly in recent color picture tubes, an FS (Flat Square) tube in which an effective surface of a panel is flattened is mainly used. In such a color picture tube, a mask body is also provided corresponding to the effective surface of the panel. Flattened. Therefore, in such a color picture tube, mislanding due to thermal deformation of the shadow mask also increases.
[0012]
Japanese Patent Application Laid-Open Nos. 61-163439 and 61-88427 disclose correction of mislanding of a color picture tube having a flat effective surface of a panel by the shape of a shadow mask. However, it is not possible to sufficiently correct a panel whose effective surface is flattened by merely changing the shape of the shadow mask.
[0013]
On the other hand, JP-A-64-17360, JP-A-1-154443, and the like disclose corrections by changing the shape of an effective surface of a panel together with a shadow mask. However, even with such corrections, the color picture tube, which has a panel with an almost spherical effective surface without a sense of incongruity, such as a color picture tube that is being developed recently, looks natural from the outer surface of the panel. Does not provide sufficient correction.
[0014]
[Problems to be solved by the invention]
As described above, in the shadow mask type color picture tube, the area occupied by the electron beam passage holes in the shadow mask is small, and most of the electron beam emitted from the electron gun collides with the shadow mask and heats up. Due to the thermal expansion, the landing position of the electron beam with respect to the three-color phosphor layer changes, and the color purity deteriorates.
[0015]
Among the changes in the landing position of the electron beam with respect to the three-color phosphor layer due to the thermal expansion of the shadow mask, the mislanding caused by heating not only the mask body but also the mask frame attached to the periphery thereof is described in the shadow mask. The correction can be made effectively by attaching the elastic support member for supporting to the mask frame via the bimetal. However, the local mislanding that occurs when a locally high-luminance image is drawn cannot be corrected by the bimetal correcting means. Note that this local mislanding is greatest at a slightly central portion side of the peripheral portion of the phosphor screen.
[0016]
In particular, in an FS tube in which the effective surface of a panel is flattened, such as a recent color picture tube, the mask body is also flattened corresponding to the effective surface of the panel, so mislanding due to thermal deformation of the shadow mask increases. I do. Conventionally, it is known to correct the mislanding of a color picture tube in which the effective surface of the panel is flattened by the shape of the shadow mask, but only by changing the shape of the shadow mask for the panel in which the effective surface is flattened. Then, a sufficient correction cannot be obtained. Further, there is also known a method of changing the shape of the effective surface of the panel together with the shadow mask for correction. However, even if the correction is made by changing the shape of the panel and shadow mask in this way, the effective surface that looks natural from the outer surface of the panel and has no uncomfortable feeling is almost spherical, like a color picture tube that is recently being developed. Sufficient correction cannot be obtained for a color picture tube having a panel.
[0017]
The present invention has been made in view of the above problems, and a shadow mask and a panel for a color picture tube having a substantially spherical panel having an effective surface that does not give a sense of incongruity so that an image looks natural from the outer surface of the panel. It is an object of the present invention to provide a color picture tube which can effectively correct the deterioration of color purity due to local thermal deformation of a shadow mask without largely changing the structure of the color picture tube.
[0018]
[Means for Solving the Problems]
In a color picture tube having a panel having a substantially rectangular effective surface with a curved inner surface, and a phosphor screen formed on the inner surface of the panel in opposition to a shadow mask, a center of the effective surface of the panel is provided. The relationship between the thickness of the panel on the short axis, the thickness of the panel on the diagonal axis, and the thickness on the long axis at the same distance from is: thickness on the short axis> thickness on the diagonal axis> long axis The thickness of the panel on the diagonal axis at the same distance between the panel thickness on the short axis and the panel thickness on the diagonal axis at the same distance from the center of the effective surface of the panel the thickness and small in half or more of the area of the distance from the center of the difference by remote least effective surface of the wall thickness of the panel on the long axis to the long axis upper end, and an outer surface of the effective surface of the panel from the spherical surface It was formed to have a substantially flat surface.
[0019]
[Action]
As described above, the relationship between the thickness of the panel on the short axis, the thickness of the panel on the diagonal axis, and the thickness on the long axis at the same distance from the center of the effective surface of the panel is the thickness on the short axis. > a wall thickness of the relationship on the thickness> major axis on the diagonal axis, the thickness of the panel on the wall thickness and the diagonal axis of the panel on the short axis at the same distance from the center of the effective surface of the panel Area where the difference from the difference between the panel thickness on the diagonal axis and the panel thickness on the long axis at the same distance is at least 1/2 of the distance from the center of the effective surface to the upper end of the long axis. small and, and the outer surface of the effective surface of the panel when a substantially flat surface constituted by the spherical surface in the curvature of the cross section parallel to the short axis of the panel inner surface in large major axis on the intermediate portion of the local thermal deformation of the shadow mask Reduce the radius so that the distance between the inner surface of the panel and the shadow mask Degradation of color purity due to local thermal deformation of the shadow mask, even for panels that have a nearly flat effective surface consisting of a spherical surface that can be kept constant and that looks natural from the outer surface of the panel and has no uncomfortable feeling Can be effectively corrected.
[0020]
【Example】
Hereinafter, the present invention will be described based on embodiments with reference to the drawings.
[0021]
FIG. 2 shows a color picture tube as one embodiment. The color picture tube comprises a panel 12 having a skirt portion 11 provided around a substantially rectangular effective surface 10 and a funnel-shaped funnel 13 integrally joined to the skirt portion 11 of the panel 12. The envelope. The outer surface of the effective surface 10 of the panel 12 has a spherical shape with a predetermined curvature described later and the inner surface also has an aspherical concave surface with a predetermined curvature described later without any unnatural feeling that the reflection is natural from the outer surface. On the inner surface of the effective surface 10 of the panel 12, a phosphor screen 14 made of a three-color phosphor layer that emits blue, green, and red light is formed. As shown in FIG. 3, the three-color phosphor layers 15B, 15G, and 15R respectively extend in the major axis (X-axis) direction with the minor axis (Y-axis) direction passing through the center of the effective surface 10 of the panel 12 as the longitudinal direction. Consists of parallel stripes. A substantially rectangular shadow mask 16 is arranged inside the panel 12 so as to face the phosphor screen 14. The shadow mask 16 includes a mask main body 17 having a predetermined curvature in which a number of electron beam passage holes are formed, and a mask frame 18 attached to a peripheral portion of the mask main body 17. Are supported by a stud pin 19 attached to the mask frame 18 and an elastic support member 20 attached to the mask frame 18 and engaged with the stud pin 19. On the other hand, an electron gun 23 that emits three electron beams 22B, 22G, and 22R arranged in a line in the same horizontal plane is disposed in the neck 21 of the funnel 13.
[0022]
Then, the three electron beams 22B, 22G, and 22R emitted from the electron gun 23 are deflected by a magnetic field generated by a deflection yoke 24 mounted outside the funnel 13, and the phosphor screen is passed through a shadow mask 16. 14 is formed in such a structure that a color image is displayed on the effective surface 10 by performing horizontal and vertical scanning.
[0023]
The outer surface of the effective surface 10 of the panel 12 is composed of a combination of two spherical surfaces having different radii of curvature, and as shown in FIG. 1, the central axis of the panel 12, that is, the central axis of the effective surface 10 (coincides with the tube axis). Assuming that the Z-axis, the radius of curvature near the center of the effective surface 10 of the panel 12 is R1, the radius of curvature of the peripheral portion of the panel 12 is R2, and the distance of the spherical surface of the peripheral portion from the center of the effective surface 10 of the panel 12 is S,
(Equation 1)

in the case of,
(Equation 2)

Becomes
(Equation 3)

in the case of,
(Equation 4)

And rf is
(Equation 5)

It becomes.
As an example,
R 1 = 1607 mm
R 2 = 1417 mm
S = 17.9 mm
It is.
[0024]
On the other hand, the inner surface of the effective surface 10 is formed in a shape represented by the following Expression 6.
(Equation 6)

Note that A _{4i + j} is a coefficient, and at the center of the effective area which is the center of the coordinates (X = 0, Y = 0),
Z = 0
Because
A ₀ = 0
, And A _{1 to} A ₁₅ are the values shown in Table 1, respectively.
[Table 1]

[0025]
As an example, FIG. 4 shows the shapes of the outer surface and the inner surface along the long axis (X axis) of the effective surface, FIG. 5 shows the shapes of the outer surface and the inner surface along the short axis (Y axis) of the effective surface, and FIG. The shapes of the outer surface and the inner surface along the diagonal axis (D axis) of the effective surface are indicated by solid lines 26X, 26Y, and 26D as outer surfaces, and broken lines 27X, 27Y, and 27D as inner surfaces.
[0026]
When the effective surface 10 of the panel 12 is configured as described above, the effective surface 10 has a thickness distribution shown in FIG. That is, the thickness distribution on the long axis is curve 28X, the thickness distribution on the short axis is curve 28Y, and the thickness distribution on the diagonal axis (D axis) is curve 28D. As a result, the difference between the thickness H1 at the point M1 on the long axis and the thickness H2 at the point M2 on the diagonal axis at the same distance from the center O of the effective surface 10 of the panel 12 is represented by a curve shown in FIG. 29, and the difference between the thickness H3 at the point M3 on the short axis and the thickness H2 at the point M2 on the diagonal axis is as shown by a curve 30. That is, the difference between the thickness H3 at the point M3 on the short axis at the same distance as the point M1 on the long axis of the panel 12 and the thickness H2 at the point M2 on the diagonal axis is the diagonal axis at the same distance. The difference between the thickness H2 at the upper point M2 and the thickness H1 at the point M1 on the long axis is smaller than the difference between the thickness H1 and the center H of the effective surface 10 of the panel 12, that is, the area of the panel 12 It is small in a region equal to or more than の of the distance from the center O of the effective surface 10 to the end in the long axis direction, and has the relationship of Expression 7.
(Equation 7)

On the other hand, the thickness distribution on the effective surface of the conventional panel is shown in FIG. 9 as a curve 32X on the long axis, a curve 32Y on the short axis, and a thickness distribution on the diagonal axis. Is shown by a curve 32D, and the difference between the thickness on the long axis and the thickness on the diagonal axis at the same distance is the thickness on the diagonal axis and the thickness on the short axis at the same distance. Is smaller than the difference. This is because the diagonal axis is closer to the long axis than the short axis. However, even when the diagonal axis is closer to the long axis than the short axis, the thickness distribution of the effective surface 10 of the panel 12 according to the above embodiment is different from that of the conventional panel. The relationship is reversed.
[0027]
When the thickness distribution of the effective surface 10 of the panel 12 is set as described above, the outer surface of the effective surface 10 of the panel 12 is flattened, and the shape formed by one or two spherical surfaces which looks natural from the outer surface without a sense of incongruity. In any case, the radius of curvature of the cross section in the direction parallel to the short axis of the inner surface (the YZ parallel cross section) at the intermediate portion of the effective surface 10 in the long axis direction can be made smaller than that of the conventional panel. As a result, the radius of curvature of the shadow mask 16 in the same direction can be reduced, and the deterioration of the color purity in the middle portion in the major axis direction where local thermal deformation of the shadow mask 16 is most likely to occur can be effectively corrected.
[0028]
As an example, for a 23-inch 110-degree deflection tube, the thickness distribution of the effective surface is set to the curves 28 X, 28 Y, and 28 D shown in FIG. Mislanding could be improved by about 15%.
[0029]
Even when the thickness distribution of the effective surface is represented by the curves 28 X, 28 Y, and 28 D shown in FIG. 7, the strength of the panel hardly changes.
[0030]
【The invention's effect】
The relationship between the thickness of the panel on the short axis, the thickness of the panel on the diagonal axis, and the thickness on the long axis at the same distance from the center of the effective surface of the panel is expressed as: thickness on the short axis> diagonal axis thick> the thickness of the long axis, the difference in thickness of the panel on the wall thickness and the diagonal axis of the panel on the short axis Metropolitan at the same distance from the center of the substantially rectangular effective surface of the panel Is smaller than the difference between the thickness of the panel on the diagonal axis and the thickness of the panel on the long axis at the same distance, at least in a region at least half the distance from the center of the effective surface to the upper end of the long axis. and the outer surface of the effective surface of the panel is substantially flat surface constituted by the spherical surface, without significantly changing the shape of the panel and the shadow mask, only by changing the curved shape partly, film from the panel outer surface Even a nearly flat panel consisting of a spherical surface that looks natural and looks natural The degradation of color purity due to local thermal deformation of the mask can be effectively corrected.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining a shape of an effective surface of a panel of a color picture tube according to an embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a color picture tube according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram of a phosphor screen formed on an effective surface of the panel.
FIG. 4 is a diagram showing shapes of an outer surface and an inner surface along a long axis of an effective surface of the panel.
FIG. 5 is a diagram showing shapes of an outer surface and an inner surface along a short axis of an effective surface of the panel.
FIG. 6 is a diagram showing shapes of an outer surface and an inner surface along a diagonal axis of an effective surface of the panel.
FIG. 7 is a view showing a thickness distribution on a long axis, a diagonal axis, and a short axis of an effective surface of the panel.
FIG. 8 is a diagram showing a difference between a thickness on a long axis and a thickness on a diagonal axis and a difference between a thickness on a diagonal axis and a thickness on a short axis in the effective surface of the panel. .
FIG. 9 is a view showing a thickness distribution on a long axis, a short axis, and a diagonal axis of an effective surface of a panel of a conventional color picture tube.
FIG. 10 is a view for explaining deterioration of color purity due to local thermal deformation of a shadow mask of a conventional color picture tube.
FIGS. 11A and 11B are diagrams for explaining the relationship between an image pattern drawn on a phosphor screen and mislanding. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Effective surface 12 ... Panel 14 ... Phosphor screen 15B, 15G, 15R ... 3 color phosphor layer 16 ... Shadow mask 17 ... Mask main body 18 ... Mask frame 22B, 22G, 22R ... 3 electron beam 23 ... Electron gun

Claims (1)

In a color picture tube having a panel in which the inner surface of a substantially rectangular effective surface has a curved surface, and a phosphor screen is formed on the inner surface of the panel in opposition to a shadow mask,
The relationship between the thickness of the panel on the short axis, the thickness of the panel on the diagonal axis, and the thickness on the long axis at the same distance from the center of the effective surface of the panel,
Thickness on the short axis> Thickness on the diagonal axis> Thickness on the long axis
And
The difference between the thickness of the panel on the short axis and the thickness of the panel on the diagonal axis at the same distance from the center of the effective surface of the panel is the thickness of the panel on the diagonal axis and the long axis at the same distance. The difference from the thickness of the upper panel is smaller than at least a half of the distance from the center of the effective surface to the upper end of the long axis, and the outer surface of the effective surface of the panel is substantially flat and spherical. Color picture tube characterized by having a smooth surface .

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