JPH06103926A - Cathode-ray tube - Google Patents

Abstract

PURPOSE: To provide a cathode-ray tube to prevent screen image distortion by defining a screen surface curvature and a design reference value of a screen surface to satisfy specific conditions so that the value of the design reference satisfies specific requirements at a predetermined boundary point. CONSTITUTION: A screen surface 11a of a cathode-ray tube 10 is irradiated through a grid-like net 100 by a light source 100. A curvature Z of the surface 11a and a design reference value P of the surface 11a are defined to satisfy the conditions specified by Equation I and Equation II respectively, where the major axis, minor axis and tube axis of the surface 11a are designated as X- axis, Y-axis and Z-axis respectively. When the value P is selected to satisfy an inequality -0.1<=P<0 with the effective boundary surface of an image plane designated as X-X1 and Y=Y1, image distortion formed on the surface 11a is prevented. Equation I: Z=A1 X<2> +A2 X<4> +A3 Y<2> +A4 Y<4> +A5 X<2> Y<2> +A6 X<4> Y<2> +A7 X<2> Y<4> +A8 X<4> Y<4> . Equation II: P=(A5 X<2> Y<2> +A8 X<4> Y<4> )/(A1 X<2> +A2 X<4> +A3 Y<2> +A4 Y<4> +A6 X<4> Y<2> +A7 X<2> Y<4> ) where A1 to A8 are coefficient for each equation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube, and more particularly to a cathode ray tube having an improved outer surface curvature of a panel to prevent distortion of an image formed on a screen.

[0002]

2. Description of the Related Art Generally, looking at the structure of a cathode ray tube, as shown in FIG. 1, a panel 11 having a phosphor screen 11a formed on the inner surface thereof and a neck portion 12a sewn to the panel 11 are formed.
A funnel 12 provided with an electron gun 13 and a deflection yoke 14 is provided inside and outside. And the panel 1
A shadow mask 15 is attached to the inside of the unit 1 so as to be separated from the phosphor screen 11a by a predetermined distance.

A conventional cathode ray tube 10 having such a structure
The electron beam emitted from the electron gun 13 provided on the neck portion 12a of the funnel 12 is deflected by the deflection yoke 14, and the horizontal direction of the phosphor screen 11a, that is, the long axis XX, as shown in FIG. Vertical direction, that is, the short axis YY
Direction is two-dimensionally scanned to form a raster on the phosphor screen 11a.

Since the outer surface of the panel of such a cathode ray tube is formed as a curved surface having a predetermined radius of curvature, when viewing an image formed on the phosphor screen 11a of the panel from the side surface of the panel, the phosphor is formed. There is a problem that the image formed on the edge of the screen 11a seems to be crushed and the viewer cannot get a flat feeling.

In order to solve the above problems, a method of forming a panel in a flat shape has been tried in the past, but the flat panel has the following problems.

1. It is difficult to maintain the structural strength against the vacuum pressure acting inside the cathode ray tube.

2. When the image formed on the phosphor screen surface is viewed from the side, the central portion of the image appears to be recessed.

3. Since the shadow mask is locally heated and thermally expanded by the electron beam emitted from the electron gun, the electron beam is not accurately landed on the phosphor screen and a color mixing phenomenon occurs.

Conventionally, in order to reduce the above-mentioned problems, the curvature of the outer surface of the panel in the diagonal direction can be expressed by a quadratic function, and the curvature by this quadratic function is flat at the corner portion of the panel. There is a region in which the value of the quadratic function becomes negative in order to be converted.

However, the panel for flattening the corner portion of the panel as described above has the following problems.

1. The design of the curvature contour of the outer surface of the panel causes a problem of external light reflection on the outer surface of the panel. In particular, since there are inflection points at the corners of the panel, ambient light radiated to the outer surface of the panel is confused around the inflection points.

2. If there is a region where the quadratic function becomes negative in the diagonal direction of the panel, the mechanical strength of the shadow mask is reduced, and thermal deformation is more likely to occur than in the conventional shadow mask.

As described above, the present inventor, in the process of examining the relationship between the outer surface of the panel and the image and the relationship that the outer light is reflected on the outer surface of the panel, has an irregular curvature on the outer surface of the cathode ray tube. In this case, the curvature of the panel and the state of the image were examined and examined through the following experiments.

That is, as shown in FIG. 3, a grid-like mesh is formed at a position separated by a predetermined distance (about 2 meters) from the outer surface of the panel of the cathode ray tube 10, that is, the outer surface of the panel facing the phosphor screen 11a. 100 is provided, the net 100 is imaged on the outer surface of the panel from the upper surface of the net 100 by using the light source 110, and the distortion of the image is analogized and interpreted by the distortion of the net 100 imaged.

However, in the cathode ray tube developed by Hitachi, Ltd. of Japan, which was measured by the above-mentioned method, the shadow of the net 100 imaged as shown in FIG. 4 is horizontal and vertical to some extent in the center of the screen surface. However, it can be seen that distortion appears sharply at the edges on both sides. In the cathode ray tube developed by Toshiba Corporation of Japan, as shown in FIG. 5, the afterimage projected on the screen surface is generally distorted at the center and the peripheral portion of the screen surface.

In the cathode ray tube as described above, when the viewer views an image formed on the screen of the cathode ray tube from the front side of the cathode ray tube, the distortion of the image is not severe, but the viewer sees the image from the side of the screen surface. When viewing, there was a problem that the image formed in the peripheral portion of the screen surface was distorted. In addition, the reflection of external light was intense on the screen surface, and a vivid image could not be viewed.

[0017]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a cathode ray tube capable of preventing an image formed on a phosphor screen from being distorted depending on a viewing angle of a viewer.

Another object of the present invention is to provide a cathode ray tube in which distortion of an image due to external light emitted from the periphery of a screen is prevented and a viewer does not feel anxiety even when viewing from any direction. It is to be.

[0019]

In order to achieve the above object, the present invention comprises a panel having a screen surface and a funnel in which the electron gun is sewn to the panel and sewn to the panel. in becomes Te cathode ray tube, X-axis and long axis of the panel, the minor axis Y-axis, the tube axis as a Z-axis, the curvature of the outer surface of the panel when the coefficient a ₁ to a _8, the following (1 )
formula,

Z = A ₁ X ² + A ₂ X ⁴ + A ₃ Y ² + A ₄ Y ⁴ + A
₅ X ² Y ² + A ₆ X ⁴ Y ² + A ₇ X ² Y ⁴ + A ₈ X ⁴ Y ⁴

Approximately, the design reference value of the outer surface of the panel is expressed by the following equation (2),

[0022]

[Equation 2]

When the value of P is defined at the boundary points (X = X1) and (Y = Y1) of the effective screen, the inequality −0.1 ≦
The feature is that P <0 is satisfied.

Another feature of the present invention is the radius of curvature R of the panel.
Is the effective diagonal length × 1.167, the X-axis radius of curvature of the panel, the Y-axis radius of curvature and the inequality RX <7R,
A grid-like net is provided on the front surface of the panel satisfying RY <7R so as to be separated by a predetermined distance, and a light source is provided on the front surface of the net, and an image is projected on the outer surface of the panel by the light emitted from the light source. When the bending degrees of the panel with respect to the vertical and horizontal axes are ΔX and ΔY and the vertical and horizontal lengths of the panel are L _X and L _Y , the panel satisfying the following formula is provided.

-0.01 <ΔY / L _X <0.01,-
0.01 <ΔX / L _Y <0.01

[0026]

By forming the curvature of the outer surface of the panel so that the lattice-shaped shadow pattern imaged on the outer surface of the panel is not distorted, it is possible to prevent the image formed on the screen of the panel from being disturbed by external light.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A typical cathode ray tube is a panel having a phosphor screen on its inner surface as shown in FIG. 1, and is sewn to the panel. An electron gun and a deflection yoke are provided inside and outside the neck portion of the panel. And a funnel. Here, in order to develop a panel in which image distortion and image interference due to reflection of external light are eliminated, the inventor of the present invention has a major axis of the X axis, a minor axis of the Y axis, and a tube axis of the Z axis. Then, when A _{1 to} A ₈ are used as the coefficients, the curvature formula of the outer surface is mixed with the elements of the quadratic equation and the quartic equation in consideration of the axial symmetry, and the following equation (1) is an approximate equation. ,

Z = A ₁ X ² + A ₂ X ⁴ + A ₃ Y ² + A ₄ Y ⁴ + A
₅ X ² Y ² + A ₆ X ⁴ Y ² + A ₇ X ² Y ⁴ + A ₈ X ⁴ Y ⁴

Approximately represented by the above-mentioned approximate expression (1)
The coefficients A _{1 to} A ₈ of are selected arbitrarily, and these coefficients are substituted into the above-mentioned approximate expression, and the outer surface curvature of the panel represented by the image of the grid-like net as shown in FIG. In order to obtain the outer surface curvature of the panel in which the pattern is not distorted, that is, the curvature of the outer surface of the panel that allows the viewer to feel a flatness, the setting criterion of the coefficient is expressed by the following equation (2),

[0030]

[Equation 3]

Was set by Then, as a result of an experiment while changing the coefficients A1 to A8 of the equation (2), the P
Boundary points ((X = X1), (Y =
Y1): X and Y are the X axis and Y from the center of each panel
It is the distance in the axial direction, X1 is half the X-axis effective screen length of the screen surface, and Y1 is half the Y-axis effective screen length. ) Has a coefficient that satisfies the inequality −0.1 ≦ P <0, distortion of the shadow pattern imaged on the outer surface of the panel facing the phosphor screen can be minimized, and the image formed on the phosphor screen can be minimized. You can prevent it from being distorted.

The present invention will now be described in more detail based on the value of P obtained by experiment while changing the coefficient of the equation (2).

FIGS. 6 to 24 were obtained by simulating the pattern of the appearing shadows by imaging a grid-like net on the curved surface of the panel obtained by changing the coefficient of the equation (1).

<Experiment 1> In designing a 29-inch cathode ray tube panel, the distance from the center of the panel to the X-axis direction is 270.4, and the distance from the center of the panel to the Y-axis direction is 202. When the value is 8, the coefficient P is obtained by substituting the coefficient into the equation (2) as shown in Table 1 below.

[0035]

[Table 1]

When the value of P in Table 1 is 0.0, the distortion state of the shadow imaged on the outer surface of the panel has a barrel shape as shown in FIG.

When the value of P is -0.025,
The distortion of the shadow pattern imaged on the outer surface of the panel is shown in FIG.
As shown in FIG. 3, the image formed on the phosphor screen of the panel was not distorted when it was completely removed by the viewer.

When the value of P is -0.1, the mesh pattern imaged on the outer surface of the panel is finely distorted into a pincushion shape at the edge of the panel as shown in FIG. The image formed on the body screen appeared distorted at its edges.

As can be seen from Experiment 1, the value of P is -0.1.
It has been found that the pattern of nets imaged on the panel is not distorted when it has a larger value.

<Experiment 2> In designing a 29-inch panel, X1 and Y1 which are boundary points that define an effective screen.
When the respective values are 270.4 and 202.8, the coefficient shown in Table 2 below is substituted into the equation (2) to obtain the value of P.

[0041]

[Table 2]

In Table 2, the value of P is -3.80303 × 1.
With 0 ⁻² , the pattern of shadows imaged on the outer surface of the panel has an undistorted grid, as shown in FIG. In this panel, the image formed on the phosphor screen was not distorted, and the image interference due to reflection of external light did not occur.

When the value of P in Table 2 is -0.110335, the mesh pattern imaged on the outer surface of the panel is distorted into a pincushion type at the edge of the panel as shown in FIG. . In such a panel, the image formed on the phosphor screen was distorted on the outer surface of the panel, and image interference due to external light appeared fine at the edge of the panel.

When the value of P in Table 2 is -0.182854, the pattern of the shadow imaged on the outer surface of the panel is pincushioned on the entire outer surface except the central portion of the panel as shown in FIG. And the distortion of the image formed on the phosphor screen also appeared on the entire outer surface of the panel except the central portion.

In Table 2, the value of P is 7.41864 × 10.
^-2 , the shadow imaged on the outer surface of the panel is
The image formed on the phosphor screen was distorted sharply in the shape of a barrel at the edge of the outer surface of the panel as shown in FIG.

When the value of P in Table 2 is 0.0, the lattice-shaped shadow imaged on the outer surface of the panel is distorted into a barrel shape at the edge of the outer surface of the panel as shown in FIG. The edges of the image formed on the phosphor screen appeared distorted.

As can be seen from Experiment 2, the value of P is -0.
By setting the coefficient to have a value of −3.80303 × 10 ⁻² which is greater than 1, a curvature of the panel is obtained in which the pattern of shadows imaged on the outer surface of the panel is not distorted and the phosphor screen of this panel is Not only does the formed image not appear distorted, but also the image is prevented from being disturbed by external light emitted from the outside of the panel.

<Experiment 3> In designing a 29-inch panel, X1 and Y1 which are boundary points that define an effective screen.
When the values are set to 270.4 and 202.8, respectively, the coefficients shown in Table 3 are substituted into the equation (2) to obtain the value of P as shown in Table 3.

[0049]

[Table 3]

In Table 3, the value of P is -2.23943 x 1
With 0 ^-2 , the pattern of shadows imaged on the outer surface of the panel has an undistorted grid, as shown in FIG.

In Table 3 above, the value of P is -6.282764 x 1
When it was 0 ^-2 , the net pattern imaged on the outer surface of the panel was pincushion-type distorted at the edge of the panel as shown in FIG.

When the value of P in Table 3 is -0.122161, the pattern of the shadow imaged on the outer surface of the panel is pincushioned on the entire outer surface except the central portion of the panel as shown in FIG. It was distorted into the form of.

When the value of P in Table 3 is 0.0, the pattern of the shadow imaged on the outer surface of the panel was distorted into a barrel shape at the edge of the outer surface of the panel as shown in FIG.

When the value of P in Table 3 is 0.1221609, the lattice-shaped shadow imaged on the outer surface of the panel is the edge of the entire outer surface excluding the central portion of the panel as shown in FIG. It was severely distorted into a barrel form.

As can be seen from Experiment 3, the value of P is -0.
When the coefficient is set to have −2.23943 × 10 ⁻² greater than 1, the outer surface curvature of the panel is obtained in which the shape of the shadow imaged on the outer surface of the panel is not distorted, and the phosphor of this panel is also obtained. The image formed on the screen was distorted and invisible, and the viewer was able to feel a flatness with respect to the outer surface of the panel when viewing the image formed on the screen of the panel. When the value of P is greater than 0, the shadow pattern imaged on the outer surface of the panel is severely distorted, and the viewer cannot perceive the flatness when viewing the image.

<Experiment 4> In designing a 20-inch panel, X1 and Y1 which are boundary points defining an effective screen.
Were set to 200 and 150, respectively, the coefficients shown in Table 4 were substituted into the above-mentioned equation 2 to obtain the value of P as shown in Table 4.

[0057]

[Table 4]

In Table 4, the value of P is -3.09353 x 1
With 0 ^-2 , the pattern of shadows imaged on the outer surface of the panel has an undistorted grid, as shown in FIG.

When the value of P in Table 4 was -0.104158, the mesh pattern imaged on the outer surface of the panel was distorted into a pincushion type at the edge of the panel as shown in FIG.

When the value of P in Table 4 is -0.155457, the pattern of the shadow imaged on the outer surface of the panel is pincushioned on the entire outer surface except the central portion of the panel as shown in FIG. It was distorted into the form of.

When the value of P in Table 4 is 0.0, the shadow pattern imaged on the outer surface of the panel was distorted into a barrel shape at the outer surface edge of the panel as shown in FIG.

When the value of P in Table 4 is 0.1041579, the lattice-shaped shadow imaged on the outer surface of the panel is the entire outer surface edge except the central portion of the panel as shown in FIG. It was severely distorted into barrel form.

As can be seen from Experiment 4 described above, the value of P is −
When the coefficient is set to have −3.09353 × 10 ⁻² greater than 0.1, the shape of the shadow imaged on the outer surface of the panel appears as undistorted, and also the phosphor screen of this panel. The image formed on the image was distorted and invisible, and no interference by external light occurred.

As can be seen from the above experiment, -0.1
When the coefficient that satisfies the value of P that is equal to or more than 0.0 and is smaller than 0.0 is set, the lattice-shaped shadow imaged on the outer surface of the panel is not distorted, and as a result, the image formed on the screen of the panel is distorted. Can be prevented from appearing. In addition, even if the outer surface of the panel is formed into a curved surface, it is possible to feel a flat feeling.

In the process of conducting the above-mentioned experiment, the present inventor determined the radius of curvature R of the panel to be the effective diagonal length × 1.16.
7, when the X-axis radius of curvature of the panel and the Y-axis radius of curvature satisfy the inequalities RX <7R and RY <7R, a grid-like net 100 is formed on the outer surface of the panel as shown in FIG. When the ratio of the distortion degree of the shadow pattern and the length of the major axis and the minor axis of the panel has a certain range, the panel is formed on the phosphor screen even though the outer surface of the panel is curved. There is no distortion of the image and it is possible to prevent the image from being disturbed by external light. This will be described in more detail. As shown in FIG. 24, the major axis of the panel, that is, the length in the X-axis direction is L _X, and the minor axis of the panel, that is, the length in the Y-axis direction is L _Y.
And the maximum bending degree in the vertical direction with respect to the Y axis and the maximum bending degree in the horizontal direction with respect to the X axis of the image irradiated on the outer surface of the panel are ΔX and ΔY, respectively, the maximum bending degree ΔX is the Y axis direction of the panel. When the value obtained by dividing the length L _Y by the length L _Y and the maximum bending degree ΔY by the length L _X in the X-axis direction of the panel is within the range of −0.01 to 0.01, the phosphor screen is formed. The displayed image is not distorted even when viewed from any direction, and the viewer can be comforted.

The inequality of the above relationship is as follows.

-0.01 <ΔY / L _X <0.01,-
0.01 <ΔX / L _Y <0.01

Explaining the relationship between the outer surface of the panel and the inequality in detail, the values of ΔY / L _X and ΔX / L _Y are −
When it has a value smaller than 0.01, it means that the shadow of the lattice mesh, that is, the shadow formed in the X-axis and Y-axis directions of the outer surface of the panel is severely bent outward from the center of the outer surface of the panel. . This shows that the surface of the panel is swelling, and the screen appears to be severely distorted in the peripheral portion, and external light incident on the surface of the panel from the surroundings is also confused in this portion.

When the values of ΔY / L _X and ΔX / L _Y are larger than 0.01, the image of the grid-like net, that is, the shadow formed on the outer surface of the panel in the X-axis and Y-axis directions. Is strongly bent from the edge of the outer surface of the panel toward the center. This indicates that the surface of the panel is dented, and the screen looks very crushed in the peripheral area, and external light incident on the surface of the panel from the surroundings is also confused in this area.

[0070]

As described above, in the cathode ray tube of the present invention, the outer surface of the panel has a curvature that does not distort the image pattern formed by projecting the grid mesh, and is formed on the phosphor screen of this panel. Even when the viewer views the image from any direction, the image formed on the phosphor screen can be prevented from being distorted and prevented from being disturbed by external light.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a general cathode ray tube.

FIG. 2 is a front view of the cathode ray tube panel shown in FIG.

FIG. 3 is a perspective view of an apparatus for imaging the shadow of a grid mesh on the outer surface of a panel of a cathode ray tube.

FIG. 4 is a plan view showing a distorted state of an image formed on a screen surface of a conventional cathode ray tube.

FIG. 5 is a plan view showing a distorted state of an image formed on the screen surface of a conventional cathode ray tube.

FIG. 6 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 7 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 8 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 9 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 10 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 11 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 12 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 13 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 14 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 15 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 16 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 17 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 18 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 19 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 20 is a plan view showing an image pattern in which a cathode ray tube is projected with an image of a grid-like net on the outer surface of the panel according to various curvatures of the panel.

FIG. 21 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 22 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 23 is a plan view showing an image pattern in which a cathode ray tube is formed by projecting an image of a grid-like net on the outer surface of the panel by various curvatures of the panel.

FIG. 24 is a plan view showing the bending degree of the image pattern of the grid-like net projected on the panel outer surface of the cathode ray tube according to the present invention and the lengths of the major and minor axes of the panel.

[Explanation of symbols]

 10 Cathode Ray Tube 11 Panel 11a Phosphor Screen 12 Funnel 12a Funnel Neck 13 Electron Gun 14 Deflection Yoke 15 Shadow Mask 100 Lattice Net 110 Light Source

[Equation 4]

Claims (2)

[Claims] 1. A panel having a screen surface,
A cathode ray tube having a funnel in which an electron gun is sewn to this panel and an electron gun is sewn into its neck portion, wherein the major axis of the screen surface is the X axis, the minor axis is the Y axis, and the tube axis is the Z axis.
When the axis is used and A _{1 to} A ₈ are used as the coefficients, the curvature of the outer surface of the panel is Z = A ₁ X ² + A ₂ X ⁴ + A ₃ Y ² + A ₄ Y ⁴ + A ₅ X ² Y ² + A ₆
It is approximately expressed as X ⁴ Y ² + A ₇ X ² Y ⁴ + A ₈ X ⁴ Y ^4, and the design standard value of the screen surface is expressed by When the value of P is defined as the boundary point (X =
X1) and (Y = Y1) satisfy the inequality -0.1≤P <0. 2. A panel having a screen surface,
A cathode ray tube comprising a funnel in which an electron gun is sewn on a neck portion of the panel, the radius of curvature of the panel being an effective diagonal length × 1.167.
In such a case, a grid-like net is separated by a predetermined distance from the front surface of the panel in which the radius of curvature of the X-axis and the radius of curvature of the Y-axis of the panel are all less than 7 times the radius of curvature of the panel. A light source is provided in front of this net, and the degree of bending of the image projected on the outer surface of the panel by the light emitted from the light source with respect to the vertical and horizontal axes of the panel is ΔX, ΔY. When the vertical and horizontal lengths are L _X and L _Y , -0.01 <ΔY / L _X <0.01, -0.01 <ΔX
A cathode ray tube comprising the above panel satisfying / L _Y <0.01.