JPH05314921A - Color picture tube - Google Patents

Abstract

PURPOSE:To prevent degradation of picture quality by forming a band-like bead part on an effective face of a shadow mask main body with a crossing angle of 20 deg. or more with respect to an electron beam passing hole row. CONSTITUTION:In an effective face 23 of a shadow mask 20, a bead part 25 crossing an electron beam passing hole row 22 in the vertical axis direction with an angle of 20 deg. or more is formed, and the bead part 25 is protruded at least 0.1mm from an effective face 23 in the peripheral part thereof. With this constitution, mechanical strength of the effective face 23 is reinforced in the horizontal axis direction as well as in the vertical axis direction to reduce arrangement turbulence of a three-color phosphor layer as well as incident position variation of three-electron beams 8B, 8G, 8R, so as to form a required color picture tube without degrading picture quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube, and more particularly to a color picture tube having a strip-shaped bead portion formed on its effective surface in order to improve the mechanical strength of a shadow mask.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 10, a color picture tube has an envelope composed of a rectangular spherical panel 1 and a funnel-shaped funnel 2 integrally joined to the panel 1. On the inner surface of 1, there is formed a phosphor screen 3 composed of a three-color phosphor layer which emits blue, green and red light. Further, a rectangular shadow mask 4 is arranged inside the phosphor screen 3 so as to face the phosphor screen 3. The shadow mask 4 has an effective surface formed into a curved surface with a predetermined curvature and having a large number of electron beam passage holes formed in a predetermined arrangement, and the effective surface has a rectangular shape facing the phosphor screen 3. It comprises a mask body 5 and a mask frame 6 attached to the periphery of the mask body 5. on the other hand,
An electron gun 9 that emits three electron beams 8B, 8G, and 8R is arranged in the neck 7 of the funnel 2.

The shadow mask 4 uses the phosphor screen 3 to emit the three electron beams 8B, 8G and 8R emitted from the electron gun 9.
The three electron beams 8B emitted from the electron gun 9 are for selecting so as to correctly enter the three-color phosphor layer of
8G and 8R are deflection yokes mounted on the outside of the funnel 2.
The phosphor screen 3 is deflected by a magnetic field generated by 10 and then selected by the shadow mask 4 to horizontally and vertically scan the phosphor screen 3, thereby displaying a color image on the phosphor screen 3.

With respect to such a color picture tube, the flattening of the screen has recently progressed, and the effective surface of the shadow mask 4 is also flattened accordingly. Therefore, when the electron beams 8B, 8G, and 8R collide with the shadow mask 4 and are heated to cause thermal expansion, so-called doming occurs in which the effective surface largely bulges toward the phosphor screen 3 side, and the three-color phosphor layer. The incident positions of the three electron beams 8B, 8G, and 8R with respect to are changed, and the image is significantly deteriorated.

As a means for suppressing the doming of the shadow mask 4, the applicant of the present invention has previously formed a belt-shaped bead portion 12 on the effective surface to form a mask body 5 as shown in FIG.
I applied for a color picture tube that suppresses doming by increasing the mechanical strength of.

However, since the bead portion 12 is formed with the horizontal axis (x axis) direction orthogonal to the tube axis (z axis) as the longitudinal direction, it is reinforced in the horizontal axis direction, but the tube axis and the horizontal direction are reinforced. In the vertical axis (y-axis) direction orthogonal to the axis, there is not much reinforcement effect, and there is a problem that doming cannot be sufficiently suppressed.

In order to reinforce in the vertical axis direction, a band-shaped bead portion whose longitudinal direction is in the vertical axis direction may be formed, but in this case, there are the following problems. That is, as in the black stripe type color picture tube which is widely used at present, an electron beam passage hole array composed of a plurality of electron beam passage holes arranged in a line in the vertical axis direction is called this electron beam passage hole array. In a color picture tube having a shadow mask arranged in a plurality of columns in the horizontal axis direction orthogonal to each other, and a phosphor screen consisting of a striped three-color phosphor layer in the vertical direction, in the vertical axis direction to the effective surface of the shadow mask. When a strip-shaped bead portion having a lengthwise direction is formed, the strip-shaped bead portion disturbs the arrangement of the three-color phosphor layer formed corresponding to the electron beam passage hole array by the photo printing method using the shadow mask. .. Further, the incident position of the electron beam on the three-color phosphor layer changes. Therefore, the appearance of the phosphor screen and the quality of the image drawn on the phosphor screen are significantly deteriorated.

[0008]

As described above, in order to suppress the doming of the shadow mask due to the collision of the electron beam, a strip-shaped bead portion is formed on the effective surface of the mask body with the horizontal axis as the longitudinal direction. There is a shadow mask that reinforces its mechanical strength. However, with this shadow mask, a sufficient reinforcing effect is obtained in the horizontal axis direction of the shadow mask, which is the longitudinal direction of the band-shaped bead portion, but in the vertical axis direction orthogonal to the horizontal axis direction that is the longitudinal direction,
There is a problem that there is not much reinforcement effect and doming is not sufficiently suppressed.

In order to reinforce in the vertical axis direction, a band-shaped bead portion having a longitudinal direction in the vertical axis direction may be formed, but a shadow mask of a black stripe type color picture tube which is now widely used practically. As described above, a color image in which an electron beam passage hole array composed of a plurality of electron beam passage holes arranged in a line in the vertical axis direction is arranged in a plurality of rows in the horizontal axis direction orthogonal to the electron beam passage hole array. In the tube, by photo printing using a shadow mask,
Since the arrangement of the three-color phosphor layer formed corresponding to the electron beam passage hole array is disturbed and the incident position of the electron beam on the three-color phosphor layer is changed, the appearance of the phosphor screen and the phosphor screen The quality of the image drawn in is severely degraded.

The present invention has been made in view of the above-mentioned problems, and the appearance of the phosphor screen and the phosphor can be obtained even if the strip-shaped bead portion having the reinforcing effect is formed in the horizontal and vertical axis directions of the shadow mask. It is an object to construct a color picture tube which does not deteriorate the quality of an image drawn on a screen.

[0011]

A curved surface having a predetermined curvature in which an electron beam passage hole array composed of a plurality of electron beam passage holes arranged in a line is arranged in a plurality of rows in a direction orthogonal to the electron beam passage hole array. In a color picture tube having a shadow mask consisting of a mask body having an effective surface facing the phosphor screen formed on the inner surface of the panel, and a mask frame attached to the peripheral portion of the mask body,
A band-shaped bead portion was formed on the effective surface of the mask body at an intersection angle of 20 ° or more with respect to the electron beam passage hole array.

Further, the strip-shaped bead portion is 1/100 to 3 / of the distance between the effective surface of the shadow mask and the inner surface of the panel.
It was formed with 100 steps.

Further, the strip-shaped bead portion is formed with a step of 0.1 mm from the effective surface of the shadow mask.

Furthermore, the band-shaped bead portion is formed into a curved surface having a radius of curvature of 1/10 or less of the radius of curvature of the effective surface of the peripheral portion of the bead portion.

[0015]

As described above, when the strip-shaped bead portion is formed on the effective surface of the mask main body at a crossing angle of 20 ° or more with respect to the electron beam passage hole array, the horizontal bead direction is orthogonal to the tube axis.
The vertical axis direction can be reinforced, and the disturbance of the stripe-shaped three-color phosphor layer formed corresponding to the electron beam passage hole array of the shadow mask and the incidence position of the electron beam on the three-color phosphor layer can be improved. It is possible to reduce the change and obtain a color picture tube which does not deteriorate the appearance of the phosphor screen or the quality of the image drawn on the phosphor screen.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on embodiments with reference to the drawings.

(Embodiment 1) FIG. 1 shows a color picture tube which is a first embodiment of the present invention. This color picture tube has an envelope composed of a rectangular spherical panel 1 and a funnel-shaped funnel 2 integrally joined to the panel 1.
On the inner surface of 1, there is formed a phosphor screen 3 composed of a three-color phosphor layer which emits blue, green and red light. The three-color phosphor layer is composed of elongated stripes in the vertical axis direction orthogonal to the tube axis. Inside the panel 1, a rectangular shadow mask 20 which will be described later is provided so as to face the phosphor screen 3.
Are arranged. On the other hand, in the neck 7 of the funnel 2, an electron gun 9 for emitting three electron beams 8B, 8G, 8R is arranged. Then, the three electron beams 8B, 8G, 8R emitted from the electron gun 9 are deflected by the magnetic field generated by the deflection yoke 10 mounted on the outer side of the funnel 2, and the phosphor screen 3 is projected through the shadow mask 20. A structure for displaying a color image is formed by performing horizontal and vertical scanning.

The shadow mask 20 is shown in FIGS.
, A plurality of electron beam passage holes formed in a curved surface with a predetermined curvature and arranged in a line in the vertical axis direction.
An effective surface in which an electron beam passage hole array 22 made up of 21 is arranged in a plurality of rows in the horizontal axis direction orthogonal to the electron beam passage hole array 22.
The mask 23 has a rectangular mask body 24 having an effective surface 23 facing the phosphor screen 3 and a mask frame 25 attached to the periphery of the mask body 24. A curved bead portion 26 is formed on the effective surface 23 so as to project toward the phosphor screen and extend through the central portion of the effective surface 23 toward the corner portion. In the illustrated shadow mask 20, two strip-shaped bead portions 26 are formed on the effective surface 23. Each bead portion 25 is, in the central portion of the mask body 23, orthogonal to the electron beam passage hole array 22 in the vertical axis direction,
The electron beam passage hole array 22 is obliquely intersected with the electron beam passage hole array 22 so that the crossing angle θ becomes smaller toward the periphery.

Thus, the effective surface 23 of the shadow mask 20
The bead part that extends in the direction of the corner through the central part
When 26 are formed, the horizontal and vertical components of the bead portion 26 cause an effective surface not only in the horizontal axis direction but also in the vertical axis direction.
It will reinforce the mechanical strength of 23. However, this bead portion 26 is formed by a photo printing method using a shadow mask,
The arrangement of the three-color phosphor layers in a striped shape elongated in the vertical axis direction of the phosphor screen 3 formed corresponding to the electron beam passage hole array 22 is disturbed, and the position of incidence of the three electron beams on the three-color phosphor layer. In order not to change the above, it is necessary to optimize the intersection angle θ of the bead portion 26 with respect to the electron beam passage hole array 22 and the protrusion height h of the bead portion 26 from the effective surface 23.

Among the optimized conditions, the protrusion height h of the bead portion 25 from the effective surface 23 is determined by the arrangement of the stripe-shaped three-color phosphor layers and the incidence position of the three-electron beam on the three-color phosphor layers. The assembling error of the color picture tube, especially the allowable error range for the distance q from the inner surface of the panel to the effective surface of the shadow mask, that is, 2/100 to 3/100 or less of the distance q from the inner surface of the panel to the effective surface of the shadow mask. is necessary. On the other hand, the minimum protruding height of the bead portion 25 is required to have a reinforcing effect of maintaining the mechanical strength of the effective surface 23 at a required size.

With respect to the protrusion height h of the bead portion 25 from the effective surface 23, FIG. 4 shows an experimental result of investigating the influence of the bead portion protrusion height h on the purity drift (PD). As can be seen from the curve 28 showing the relationship between the protrusion height h of the bead portion and the degree of improvement of the purity drift, if the bead portion protrudes at least 0.1 mm from the effective surface of the peripheral portion of the bead portion, Purity Drift 10
% Or more, and a sufficient reinforcing effect can be obtained.

The electron beam passage hole array 22 of the bead portion 25
For the intersection angle θ with, the visual distinction level (BC level) for the disturbance of the arrangement of the three-color phosphor layer was divided into 10 levels in FIG. 5, and the non-defective level that does not impair the quality of the phosphor screen was determined as 5. The test results are shown. The intersection angle θ
From the curve 29 showing the relationship between the visual sense level and the visual sense discrimination level, it was found that the intersection angle θ with the electron beam passage hole array that does not impair the quality of the phosphor screen is 20 ° or more.

From the above results, on the effective surface 23 of the shadow mask 20, a bead portion 25 that intersects the electron beam passage hole array 22 in the vertical axis direction at an angle of 20 ° or more is formed, and the bead portion 25 is formed. By projecting at least 0.1 mm from the peripheral effective surface 23, the mechanical strength of the effective surface 23 is reinforced not only in the horizontal axis direction but also in the vertical axis direction. 3 electron beam 8B, 8G for body layer,
It is possible to reduce the change in the incident position of 8R and obtain a required color picture tube that does not deteriorate the image quality.

The shadow mask 20 having the bead portion 25 on the effective surface 23 is formed by using a flat plate-shaped flat mask in which a predetermined electron beam passage hole is formed, as shown in FIG. Molded surface with the same curved surface as
A die 33 having a molding surface 31a and a bead molding die 32 attached to the molding surface 31a, and a molding surface 31b having the same curved surface as the curved surface of the effective surface.
It can be molded by using a press molding die including a punch 35 having a concave groove 34 corresponding to the bead molding die 32 on the molding surface 31b.

(Embodiment 2) FIG. 7 shows a shadow mask of the second embodiment. In this shadow mask, a bead portion 26 having a curved surface with a small radius of curvature r is formed on an effective surface 23 having a radius of curvature Ry in which a plurality of vertical electron beam passage holes are arranged in the horizontal axis. It is formed so as to intersect the row of through holes at an angle of 20 ° or more. Even when the bead portion 26 having a curved surface with a small radius of curvature r in the cross section is formed on the effective surface 23 in this manner, the protruding height from the effective surface 23 is the same as the above because of the mechanical strength reinforcement of the effective surface 23. As described in the embodiment, 0.1 mm or more is required.

In particular, like the bead portion 25 of this example, the cross section is a curved surface having a small radius of curvature r, and the bead portion 25 is formed.
Is formed with the effective surface 23 and a clear inflection point as shown by points 37a and 37b, the radius of curvature r of the bead portion 25 is
By setting r ≦ Ry / 100 with respect to the radius of curvature Ry of the effective surface 23 at the peripheral portion of the bead portion 25, the arrangement of the three-color phosphor layers is disturbed,
Also, it is possible to reduce the change in the incident position of the three-electron beam with respect to the three-color phosphor layer and to obtain a required color picture tube that does not deteriorate the image quality.

When the bead portion 25 does not have a clear inflection point with respect to the effective surface 23, r ≦ Ry / 10 is set, and the arrangement of the three-color phosphor layers is disturbed and the three-color phosphor layers are disturbed. (3) Disturbance of the incident position of the three electron beams can be reduced, and a required color picture tube that does not deteriorate the image quality can be obtained.

(Embodiment 3) FIG. 8 shows a shadow mask of a third embodiment. This shadow mask has a pin cushion defined by a curved boundary line 38 extending in the four corner directions from the central portion of an effective surface 23 in which a plurality of vertical electron beam passage hole rows are arranged in the horizontal axis direction. The bead portion 26 in the shape of a circle is formed. Effective surface of this bead part 26
The boundary line 38 with 23 is 20 ° with respect to the electron beam passage hole array.
They intersect at the above angles. Also, the effective surface 23 of the bead portion 26
The protrusion height from is 0.1 mm or more.

Even if such a bead portion 26 is formed on the effective surface 23 of the shadow mask, the arrangement of the three-color phosphor layer is disturbed and the three-electron beam is incident on the three-color phosphor layer as in the above embodiment. It is possible to reduce the change in the position and obtain a required color picture tube that does not deteriorate the image quality.

(Embodiment 4) FIGS. 9A and 9B show a shadow mask of a fourth embodiment. Of these, Figure 9
The shadow mask of (a) is a shadow mask in which the effective surface 23 is a composite curved surface of two radii of curvature Ry1 and Ry2, and an inflection point is provided at the connection between the curved surface of curvature radius Ry1 and the curved surface of curvature radius Ry2. The strip-shaped bead portion 26 having 37 is formed.

The shadow mask of FIG. 9B is also a shadow mask in which the effective surface 23 is a compound curved surface having two curvature radii Ry1 and Ry2, and the effective surface 23 has a curvature radius Ry1 and a curvature radius Ry2. The bead portion 26 having a radius of curvature r is formed at the connecting portion with the curved surface of the
Where r ≦ Ry1 / 100 and Ry2 / 100.

Even if such a bead portion 25 is formed on the effective surface 23 of the shadow mask, the disorder of the arrangement of the three-color phosphor layer and the change of the incident position of the three-electron beam on the three-color phosphor layer are reduced. Thus, it is possible to obtain a required color picture tube that does not deteriorate the quality of the image.

[0033]

When the strip-shaped bead portion is formed on the effective surface of the mask body of the shadow mask at an intersection angle of 20 ° or more with respect to the electron beam passage hole array formed on the effective surface, it is orthogonal to the tube axis. It is possible to reinforce not only in the horizontal axis direction but also in the vertical axis direction, and it is possible to suppress the doming of the shadow mask caused by the collision of the electron beam, and also to form the stripe-shaped 3 corresponding to the row of electron beam passage holes of the shadow mask. The disturbance of the color phosphor layer and the change of the incident position of the electron beam on the three-color phosphor layer can be reduced so that the quality of the image is not deteriorated.

In particular, the strip-shaped bead portion is 1 / of the distance between the effective surface of the shadow mask and the inner surface of the panel with respect to the effective surface.
100 to 3/100 steps or 0.1 mm with effective surface
The desired color picture tube can be easily constructed by forming the curved surface with a radius of curvature of 1/10 or less of the radius of curvature of the effective surface in the peripheral portion of the bead portion.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube which is a first embodiment of the present invention.

2 (a) is a plan view showing the structure of the shadow mask, FIG. 2 (b) is a front view thereof, and FIG. 2 (c) is a side view thereof.

FIG. 3 is a diagram showing a relationship between an electron beam passage hole array on an effective surface of the shadow mask and a bead portion.

FIG. 4 is a diagram showing a relationship between a bead portion of an effective surface of the shadow mask and a purity drift.

FIG. 5 is an intersection angle of a bead portion with respect to an electron beam passage hole array on an effective surface of the shadow mask and three of a phosphor screen.
It is a figure which shows the relationship with the visual sense determination level with respect to the disturbance of a color fluorescent substance layer.

6 (a) and 6 (b) are views of a press-molding die for forming a bead portion on an effective surface.

FIG. 7 is a drawing for explaining the structure of the shadow mask of the second embodiment of the present invention.

8A is a plan view for explaining the structure of a shadow mask according to a third embodiment of the present invention, and FIG. 8B is a side view thereof.

9 (a) and 9 (b) are views for explaining the structure of the shadow mask of the fourth embodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a conventional color picture tube.

FIG. 11 is a view showing a structure of a shadow mask in which a bead portion is formed on an effective surface, which was previously applied.

[Explanation of symbols]

 1 ... Panel 3 ... Phosphor screen 8B, 8G, 8R ... 3 Electron beam 9 ... Electron gun 20 ... Shadow mask 21 ... Electron beam passage hole 22 ... Electron beam passage hole array 23 ... Effective surface 24 ... Mask body 25 ... Mask frame 26 ... Bead part

Claims (4)

[Claims] 1. An effective surface formed of a curved surface having a predetermined curvature in which a plurality of electron beam passage hole rows, which are arranged in a row, are arranged in a direction orthogonal to the electron beam passage hole row. In a color picture tube provided with a shadow mask consisting of a mask body facing a phosphor screen formed on the inner surface of the panel and a mask frame attached to the peripheral portion of the mask body, the effective surface of the mask body is A color picture tube, characterized in that band-shaped bead portions are formed which intersect at an intersection angle of 20 ° or more with an electron beam passage hole array. 2. A strip-shaped bead portion is formed at an intersection angle of 20 ° or more with respect to the electron beam passage hole array, and 1/100 to 3 of the distance between the effective surface of the shadow mask and the inner surface of the panel.
The color picture tube according to claim 1, wherein the color picture tube is formed with a step difference of / 100. 3. The strip-shaped bead portion is formed at an intersection angle of 20 ° or more with respect to the electron beam passage hole array, and the bead portion is formed with a step of 0.1 mm from the effective surface of the shadow mask. The color picture tube according to claim 1, wherein 4. A band-shaped bead portion is formed at an intersection angle of 20 ° or more with respect to an electron beam passage hole array, and the bead portion is 1/1 of a radius of curvature of an effective surface of a peripheral portion of the bead portion.
The color picture tube according to claim 1, wherein the color picture tube is formed on a curved surface having a radius of curvature of 0 or less.