JPS60177534A - Color picture tube - Google Patents

Abstract

PURPOSE:To suppress doming of a shadow mask in the initial stage of an action by making the curved surface of the shadow mask to be corrugated centering around the tube axis while being in the shape of a shell where a ridge of the wave passes through the tube axis or by the tube axis. CONSTITUTION:The curved surface of a shadow mask is corrugated consisting of a ridge and a valley centering around the tube axis while a wave ridge is symmetrically formed so as to pass through the tube axis or pass by the tube axis while lying on the rectangular opposite angle of the whole frame. Thereby, mislanding generated due to thermal deformation of the shadow mask can be sharply suppressed while improving deterioration of color purity such as color slipping off and color unevenness from the initial stage of an action extending over long hours.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color picture tube, and particularly to a shadow mask thereof.

[Technical background and problems of the invention]

In general, a color picture tube has an envelope typically made of glass, as shown in Figure 1, consisting of a substantially rectangular panel (a funnel-shaped funnel (2) and a neck (3)). The inner surface of the panel is provided with a striped phosphor screen (4) that emits red, green and blue light respectively, while the net (3) is provided with a striped phosphor screen (4) that emits red, green and blue light, arranged in a row along the horizontal axis of the panel. A so-called in-2-in type electron gun (6) that emits three electron beams corresponding to , green, and blue is installed inside the screen (4) and the electron gun (6). A shadow mask (5) in which a large number of slit holes are arranged vertically in close proximity to and opposite to the frame A (7), and a large number of slit holes are arranged in a horizontal direction.
Supported through. In such a color picture tube, three in-line arrays of electron beams are deflected by a funnel (2) and an external deflection device (not shown) VC, which forms a substantially rectangular panel (1) with a corresponding rectangular shape. The colors are sorted through the slit holes of the shadow mask (5) so as to scan the area, and the striped phosphors are emitted with corresponding emitted light to reveal a color image. Here, the number of pitches in which the slit holes of the shadow mask are arranged in the horizontal direction must be % of the pitch number of the striped phosphors.

Therefore, normally the effective electron beam passing through the slit hole is A
The remaining electron beams impinge on the shadow mask and heat the shadow mask up to about 80° C. in some cases. Nyadou mask with slit holes (
5) The main body is generally made of a thin plate with a thickness of 0.1 to 0.3 mm mainly composed of iron with a relatively large coefficient of thermal expansion, and the peripheral part is surrounded by a strong mask frame (7) with a thickness of about 1 mm. is fixed. The electron beam that hits the main body of the shadow mask (5) heats and expands the shadow mask, changing the distance between the phosphor screen and the shadow mask (hereinafter referred to as the q value), and when the change in the q value exceeds a permissible value, the electron beam The beam does not correspond accurately to the striped phosphor, resulting in so-called mislanding and deteriorating color purity.

In order to prevent this, as shown in VC Publication No. 44-3547, the mask frame is fixed to the panel side wall via a bimetal, and the entire shadow mask is moved toward the screen to substantially reduce the change in the q value. A method has been adopted to keep it within an acceptable range. However, since the heat capacity of the mask frame is larger than that of a shadow mask, the heating process first heats the center of the shadow mask, the periphery, and the mask frame. moves in a dome shape, causing local q-value changes. That is, the problem is that the color purity deteriorates until the bimetallic action becomes stable.

As is well known, the amount by which the central portion of the shadow mask is deformed into a dome shape is greater when the curvature of the curved surface of the shadow mask is smaller. In other words, the larger the radius of curvature (hereinafter referred to as mask-R) of the cross section of the shadow mask curved surface, that is, the flatter it is, the larger the amount of deformation (hereinafter referred to as the amount of doming) is, and the easier it is to cause deterioration of color purity.

Therefore, it is convenient to increase the curvature of the Nyadoku mask (
A method to reduce the deterioration of color purity is to reduce the mask size.

Conventionally, in a shadow mask type color picture tube having a striped phosphor screen, the horizontal slits of the shadow mask opposite to the stripes are The interval is gradually increased in the end direction of the horizontal axis, and the curvature of the shadow mask in the cross section of the horizontal axis is increased.

However, increasing the stripe spacing at the horizontal axis end of the screen degrades the resolution, which is uniquely determined by the stripe spacing, and as a result, this appears as a deterioration in the sharpness of the peripheral area of the color picture tube screen. Put it away. Therefore, in the conventional technology, the design has to be made with a compromise between the deterioration of resolution in this vicinity and the amount of deterioration of color purity due to doming of the shadow mask.

[Purpose of the invention]

The present invention line has been developed in view of the above points, and it sufficiently suppresses the 9 beam 2nding deviation across the entire screen and for a long period of time from the initial stage of operation, and suppresses color purity deterioration such as color deviation of the image. It is an object of the present invention to provide a picture tube in which resolution deterioration in the periphery of the screen due to the expansion of the stripe interval is reduced.

[Summary of the invention]

In the present invention, the curved surface of the shadow mask of a color picture tube is shaped like a wave with the tube axis as the center, and the ridge of the wave is shaped like a shell passing near the tube axis or the moving axis. A color picture tube that can suppress mask doming.

[Embodiments of the invention]

The present invention will be explained in detail below based on examples.

Since the overall configuration of the color picture tube to which the present invention is applied is the same as that shown in FIG. 1, the explanation of the overall configuration will be omitted and will not be repeated.

First, in describing embodiments of the present invention, the basic concept thereof will be explained.

As shown in FIG. 2(a), in a general color picture tube using a Yato mask having an approximately spherical curved surface, the shadow mask (5) is damaged by electron beam heating at the initial stage of operation as described above. Doming is performed toward the inner surface of the panel as shown by the dotted line. In other words, the domed shadow mask (8) has a substantially spherical curved surface with a larger curvature in the convex direction of the curved surface of the shadow mask (5) at room temperature.
What is important here is that the shadow mask (5) is thermally deformed in the direction of the curved surface of the shadow mask (5) before operation at room temperature, in this case in the convex direction.

Also, as shown experimentally in Section 21), electron gun (6)
In the force 2 picture tube with a convex shadow mask (9) arranged between the sides, it can be confirmed that doming occurs in the direction of the electron gun (6).

From the above point of view, if multiple uneven surfaces are superimposed on the curved surface of the conceptual V-Koha/Yado mask, it is possible to disperse the amount of thermal deformation of the entire shadow mask, in other words, the amount of doming between the λ clean side and the electron gun side. Dera 9 can reduce the amount of doming of the entire shadow mask.

Based on this idea, Japanese Patent Laid-Open No. 53-52054 also makes a proposal as shown in FIG. 3. In other words, it has a parallel wavy surface surrounded by two wavy sides and two other sides, and is partially supported by support means attached to a plurality of points of inflection along the wavy two sides. This is the Nyadou mask that was supported. However, in a general 2-picture tube, the phosphor arrangement of the screen must be regularly dense, and the pitch p and q value of the apertures in the shadow mask must maintain a predetermined relationship. That is, funnel shape,
Based on the combination of the electron gun structure and the deflection device configuration, the relationship between the pitch and the q value remains approximately proportional at any position on the shadow mask and screen surface.

In other words, at a position where the q value is large, it is necessary to enlarge the aperture pitch of the shadow mask at the corresponding position. Also, if the aperture pitch and curved surface of the shadow mask are specified,
Correspondingly, the curved surface of the inner surface of the panel also needs to be roughly aligned with the curved surface of the shadow mask so that q(IE%) is approximately constant.

Furthermore, since the electron beam is deflected by a simple increase toward the periphery of the tube axis, the shadow mask that defines the position of the electron beam and the inner surface of the panel where the electron beam lands are also deflected from the tube axis to the periphery. It goes without saying that it is advantageous for mass production if the change is simple.

Therefore, in the shadow mask channel shown in Fig. 3, the hole pitch of the shadow mask is very complicated (approximately proportional to the q value), and the shape of the shadow mask from the tube axis to the periphery and the panel Since the distance between the electron beam and the phosphor screen changes in an extremely complicated manner, it becomes extremely difficult to match the electron beam to the phosphor screen. Further, a complicated structure in which the inflection point is used as a support part is disadvantageous in terms of mass production. Therefore, although such a structure is theoretically possible, it is completely undesirable for mass-produced products.

FIG. 4 is a schematic diagram showing an embodiment of a shadow mask applied to the color picture tube of the present invention designed based on the above basic viewpoint. This is a turn diagram of contour lines in the axial direction. In other words, the curved surface of the shadow mask is wavy, consisting of ridges and valleys centered on the tube axis, and the ridges of the waves extend across the entire frame through the tube axis or near the tube axis. It is symmetrically formed so that it lies on the diagonal of a rectangle.

As shown in FIGS. 6 and 7, the curved surface of this shadow mask includes the tube axis (two axes) and has multiple angles θ from the vertical axis (Y axis).
A rough curved surface whose cross section on the plane is an arc of radius Rm.The typical curved surface formula is Rmtθl=A + B Oos
It is expressed as 2θ+00os4θ. Furthermore, the curved surface type of the inner surface of the panel was also the same as above. 1 with a relatively flat screen
The first example shows the application to a 9-inch 90° deflection color picture tube.
Shown in the table.

In Table 1, the conventional shadow mask means that the horizontal pitch of the apertures of the shadow mask is 0.70 mm at the center.
, and the peripheral area is 9.84 aoa.

The horizontal pitch of the openings of the shadow mask in the embodiment is 0 at the center, and the pitch is 7 om, and the other pitches are uniquely determined by the distance (q value) between the inner surface of the panel and the mask.

In this embodiment, since the inner surface of the panel is also changed to match the curved surface of the shadow mask, the horizontal pitch of the shadow mask in the horizontal peripheral portion is approximately 0.84 mm, which is approximately the same as in the conventional example.

Of the thermal deformations of the shadow mask, local doming is the most significant and tends to impair image quality and color purity. In the striped screen color picture tubes most commonly used, vertical landing changes can be ignored. Therefore, as shown in Fig. 8, for example, to monitor the operation of a 19-inch square picture tube, a high-voltage 26 KV power source current 900 μ゛A1 white band-shaped signal αυ with a width of 80 mm is placed on a black background. On the other hand, it is generally known that the color purity of an image ζ vertically located in the middle of the horizontal axis is most likely to deteriorate. FIG. 9 schematically shows the thermal deformation pattern of the conventional shadow mask at this time.

That is, Fig. 9 shows the thermal deformation state at room temperature, and Fig. 9 bJ shows the thermal deformation state at high temperature corresponding to Fig. 8.
FIG. 8(b) shows that the temperature of the shadow mask portion opposite to the white signal portion α of the image shown in FIG. 8 has increased to about 80°0, causing local doming of about 800 μm.

FIG. 10 shows the thermal deformation pattern of the shadow mask shown in FIG. 4. The image signal pattern is the same as the image in FIG. In FIG. 10, a point P on the shadow mask facing the center of the white signal portion aυ on the horizontal axis (X axis)
indicates that the thermal liquid level increases by about 200 μm in the direction away from the phosphor screen, and the position Q of the maximum thermal displacement is outside the area on the shadow mask opposite to the white signal part I, and is located between the white signal part aυ and the tube axis. is at the midpoint of , and its maximum thermal displacement is
It was confirmed through experiments and structural analysis calculations that the thickness of the phosphor screen was approximately 500 μIn.

r+=t, the amount of thermal displacement of the shadow mask at point V in the ito diagram (approximately 200 μm) is greater than that of the conventional shadow mask (
The maximum variation of the shadow mask of the present invention is approximately 500μ! n is 65% or less of that of the conventional shadow mask9, and the maximum displacement point Q of the shadow mask of the present invention is in the direction from the white signal area Uυ to the center of the shadow mask where the amount of mislanding relative to the amount of mask displacement is generally small. It slips away.

Therefore, the deterioration in color purity of the received image as shown in FIG. 8 can be significantly improved. It goes without saying that deterioration in color purity at the initial stage of operation due to other images, for example, all-white image signals, can also be significantly improved.

In addition, the pitch of the shadow mask can be made into almost the same pattern as the conventional one by making the inner surface of the panel and the curved surface of the shadow mask into a wave shape centered on the tube axis, and manufacturing of the shadow mask is also relatively easy. It's easy to do.

〔Effect of the invention〕

As described above, according to the present invention, by making the inner surface of the panel and the curved surface of the shadow mask wave-shaped with the ridge passing through the tube axis, thermal deformation of the shadow mask, which has been considered extremely difficult to prevent, can be prevented. It is possible to significantly suppress the occurrence of erroneous 2nd-ordering, and it is possible to improve color purity O-deterioration such as color shift and color unevenness for a long time from the initial stage of operation.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing the schematic structure of a shadow mask type color picture tube, Figures 2(a) and 2Φ) are schematic diagrams for explaining the doming of the shadow mask, and Figure 3 is a schematic diagram of the shadow mask. A schematic configuration diagram showing an example, FIG. 4 is a pattern diagram showing a curved surface of a shadow mask applied to an embodiment of the present invention, FIG. 5 is a pattern diagram showing the contour purity of FIG. 4,
6 and 7 are schematic diagrams for explaining the cross-sectional shape of the shadow mask shown in FIG. 4, FIG. 8 is a schematic diagram for explaining the signal pattern, and FIGS. 9(a) and 9 (b) is a pattern diagram explaining thermal deformation of the shadow mask,
FIG. 10 is a % pattern diagram for explaining thermal deformation of the shadow mask shown in FIG. 4. (Panel (2)...Funnel (3)...
・Neck (4)...Phosphor screen (5)...
Shadow Mask (6)...Electron Gun (7)...Mask Frame Agent Patent Attorney Noriyuki Chika (and 1 other person) No. 1
Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 γ Figure 7 Figure 8/1 Figure 9

Claims (1)

[Scope of Claims] 1) An envelope in which a substantially rectangular panel, a funnel-shaped funnel, and a neck are connected, a phosphor screen formed on the inner surface of the panel, and a phosphor screen disposed inside the neck, the screen being disposed inside the neck. A collar comprising an electron gun that emits a plurality of electron beams that cause excited light emission, and a shadow mask that is located between the screen and the first section gun and is arranged close to and opposite to the screen and has a large number of apertures arranged. In the picture tube, at least the curved surface of the shadow mask among the curved surfaces of the inner surface of the panel and the shadow mask has a wave shape consisting of ridges and valleys centered on the tube axis, and the ridges of the waves extend along the tube axis or near the tube axis. A color picture tube characterized by the passage of light. 2) The force 2-picture tube according to claim 1, wherein the wave ridges of the shadow mask periodically apply spinal pressure in the radial direction of the circumference centered on the tube axis. 3) Claims 1 and 2, characterized in that the radial period of the circumference of the wavy ridges on the inner surface of the panel and/or the curved surface of the shadow mask is approximately equal around the tube axis. Color picture tube as described. 4) Claim 1, characterized in that the wave-shaped ridges or troughs are located on at least one or more of the vertical axis, horizontal axis, and diagonal axis, or on one or more of the vicinity of the three axes. Color picture tube as described.