JPS587224B2 - color - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube equipped with a three-electron beam in-line type electron gun and formed with a striped phosphor screen. The present invention relates to a color picture tube in which shadow mask surfaces forming through holes both have a single radius of curvature.

An example of a striped screen color picture tube with a three-electron beam in-line electron gun has a structure as schematically shown in FIG.

That is, the picture tube includes a tube consisting of a face plate 1, a cone part 2, and a neck part 3, and an in-line arrangement 3 and an electron gun assembly 4 are installed in the neck part.

Further, a shadow mask 5 is installed inside the face plate at intervals of about 10 mm, and slit-like through holes 6 are arranged on the entire surface of the shadow mask 5, and the direction thereof is aligned with the vertical axis of the screen.

The three color beams emitted from the three in-line electron guns pass through slit-like holes and strike the three-color phosphor screen γ formed in stripes on the inner surface of the face plate, producing color. It generates images.

Conventionally, the color picture tube described above has a structure in which the inner surface of the face plate has a biradiant surface shape and a shadow mask surface has a spherical shape, or a structure in which these shapes are reversed.

The former type of conventional picture tube is schematically shown in FIG. 3 and will be explained.

Figure a shows a cross section along a horizontal plane including the tube axis Z, and the screen 7 is represented by the circumference of a solid line drawn by the shortest radius Rf-min.

Figure b shows a cross section along a vertical plane including the tube axis Z, and the screen 7 is represented by a solid line circumference with a maximum radius Rf-max.

Note that in both cross sections, the shadow mask 5 has a circumference drawn with a radius.

In contrast, in the present invention, it is attempted to make it possible to form both the inner surface of the face plate and the surface of the shadow mask into a spherical shape with a single radius, and to arrange these points at predetermined intervals, generally at equal intervals, over the entire surface of the screen. This is achieved by changing the interval between the holes in accordance with the position of the striped phosphor so that the beam passes through the slit-like holes on the shadow mask surface and impinges on the striped phosphor. .

The picture tube of the present invention thus constructed is characterized by superior explosion-proof characteristics, manufacturing precision, productivity, etc., as compared to the conventional picture tube described above.

Hereinafter, the picture tube of the present invention will be explained in more detail with reference to the drawings.

Center gun G installed on tube axis Z in Fig. 4a
Consider a center beam emitted from zero.

This center beam is deflected by a deflection system, passes through a point Q on the surface of the shadow mask Sm, and then reaches a point P on the surface of the screen Sr.

The intersection of the straight line PQ and the tube axis is the deflection center O of the center beam.
shall be.

This deflection center O moves forward as the deflection angle γ increases, and γ=
The amount of advance from the center of deflection at 0 is called Δp.

Since the distance L from the deflection center 0 to the point P on the screen surface (see b in the same figure) is determined by the position of the point P, the second
It becomes a function of (θ, γf) shown on the screen surface 7 in the figure.

Next, the deflection center of the side beams emitted from the pair of side guns G, G2 is determined.

These side beams are also deflected by the deflection system, and after passing point Q on the shadow mask surface, point P on the screen surface,
, P2 is reached.

The screen surface near point P is approximated by a tangent plane p at point P.

Considering a plane m that includes the center beam deflection center and is parallel to the tangent plane, points S1 and S2 where the straight lines P2Q and PIQ intersect with this plane m are set as the deflection centers of the side beams.

In an ideal deflection system, the deflection centers of three electron guns are 0, S1, and S2.
are on a straight line on the horizontal plane, and os1=082 (=S) holds true for the distance between the three points.

This S becomes a function of (θ, γf) similar to the above-mentioned (θ, γj).

In Fig. 4b, if the value of the distance PQ from the screen surface to the shadow mask surface is expressed as q(θ, γf), then the distance W(
θ, γf) is the through hole interval a(θ, γf), and (θ, γf) is
f) and q(θ, γf).

Furthermore, the distance between the center beam and the side beams δ(θ, γ
f) is expressed as.

In order for the beam spacing to be equal on the screen surface, W (θ, γf) − 3δ (θ, γf) (3)
Therefore, this and equation (1). From (2), the hole spacing a(θ, γf) is given by the following equation.

However, since this equation (4) contains many indeterminate elements, a general solution is that the slit-like through-hole spacing a(
θ, γf) is difficult to determine.

Here, in the present invention, the horizontal circumference of the inner surface of the face plate in a conventional picture tube, that is, a conventional picture tube equipped with a face plate having a dual-emissive inner surface shape and in which the through-hole interval is constant over the entire surface of a spherical shadow mask. With the intention of replacing the two picture tubes with a spherical face plate having an inner surface that corresponds to the inner surface of the picture tube, the hole spacing a(θ, γf) is determined by comparing the two picture tubes.

The picture tube of the present invention will be described with reference to FIG. 3, which shows a conventional picture tube. In the horizontal cross section of FIG. coincides with the solid line circumference of the screen 7.

In the vertical cross section of Figure b, the dotted circumference of screen 1' has the same radius as screen 7' in Figure a, so it only touches the screen 1 of the conventional tube on the tube axis Z; They gradually become more distant as they move away from each other.

Furthermore, in order to further clarify the relationship between the picture tube of the present invention and the conventional picture tube, their main elements are listed in Tables I and H below.

Is the conventional pipe as shown in Table I? The radius of curvature of the inner surface of the biradiant face plate is R7+(θ), the radius of curvature of the spherical shadow mask surface is Rm, and the distance between the face plate and the shadow mask (on the tube axis) is q.

, the constant through hole spacing is set to a, and in the picture tube of the present invention, the radius of curvature of the inner surface of the spherical face plate is set to R72 as shown in Table H, and Rm and q are set to the same values as above. be.

Comparing both picture tubes above, the function L(θ
, γf), and q(θ, γf).

It can be said that (θ, γf) is determined by the radius of curvature of the face plate and the deflection system.

Although there is a slight difference in this radius of curvature between Rf+(η) and Rf2 of each tube, it is negligible compared to the difference in q(θ, γf).

Also, both tubes use a common deflection system (θ, γf
) has the same function for both the conventional pipe and the pipe of the present invention.

Next, S(θ, γf) is determined by the deflection system and the electron gun, but since these are also common, S(θ, γf) is the same function for both tubes.

Here, when formula (4) is rewritten for the conventional picture tube (subscript 1) and the picture tube of the present invention (subscript 2), formulas (5) and (6) are obtained.

In this equation (7), qI(θ, γf)−, q2(θ, γf
) cannot be easily determined, so as an approximation of these, q′I(θ, γ7) and q6(
θ, γf) are defined.

That is, in FIG. 5, when M is the intersection of a straight line parallel to the tube axis passing through point F on the inner surface of the face plate, which is at a distance of γf from the tube axis Z, and the shadow mask surface, the above qi(θ, γf ), q'2(θ, γf).

Since the value of the distance FM on the tube axis is qo as described above, the following equation holds true.

In the picture tube of the present invention, both the inner surface of the face plate and the surface of the shadow mask are spherical, so q6(θ, γf
) is a function q'2(γf) of only γf,
From equations (8), (9), and (10), q′, (θ, γf),
q'2(γf) is expressed as follows.

As can be seen, the hole spacing is expressed by equation (13) (
Since it is determined as a function of θ, γf), it can be easily obtained.

Next, as shown in the right column of Table I as a specific example, Rm=8
15.0, qo=9.1, a1=0.80 (unit: mm)
The picture tube of the present invention corresponding to the conventional type 19 color picture tube has R72=814.0 (the value of R7r(θ) on the horizontal axis at θ=90°), Rm=815.0.
0, q0 = 9.1, and the actual values of a2 (θ, γf) of the main area on the shadow mask surface of such a picture tube are as obtained from Figs. 6 and 7. It is.

In other words, the hole spacing on the horizontal axis is 0.8 m, the same as in conventional pipes.
m, but on the vertical axis it increases as you move away from the center and becomes 0.8 x 1.1 mm at the periphery.
The area around the diagonal axis is 0.8 x 1.04 mm.

As is clear from the above, according to the present invention, it is possible to design a color picture tube in which both the inner surface of the face plate and the surface of the shadow mask have a spherical shape with a single radius of curvature, thereby improving the productivity of the face plate and shadow mask. , explosion-proof properties, and manufacturing precision can be improved.

Furthermore, since the slit-like holes of the shadow mask can be aligned over the entire surface of the shadow mask so as to correspond well to the striped phosphors on the screen of the face plate, beam landing is excellent, and the margin at the periphery is excellent. This makes it possible to easily adjust color purity and generate high-quality images, which is extremely effective in practice.

[Brief explanation of the drawing]

Figure 1 is a horizontal longitudinal cross-sectional view of a general example of an in-line three-electron gun type striped screen color picture tube, Figure 2 is a plan view of the screen, and Figures 3 a and b show the inner surface as a bi-radial surface and a spherical surface. 4a and 4b are explanatory views of the color picture tube according to the present invention and an enlarged view of the main parts thereof. 5 is another explanatory diagram of the color picture tube of the present invention same as the above, and FIG. 6 is a curve diagram showing the interval value of the slit-like through holes in the main part on the shadow mask of the color picture tube of the present invention same as the above. The figure is a local distribution diagram of slit-like holes on the shadow mask surface (first quadrant). 8m...Shadow mask, Sr...Screen, a(θ
, γf)... Distance between adjacent slit-like holes on the Sm surface, W
(θ, γf)... Distance between adjacent center beams on the Sr surface.

Claims (1)

[Claims] 1. A color picture tube comprising a face plate and a shadow mask facing the same, and 3 an electron beam in-line type electron gun, including a screen in which striped phosphors are arranged on the inner surface of the face plate, and a shadow mask having a large number of slit-like through holes arranged and corresponding to the striped phosphor;
Each of the slit-like through holes has a single radius of curvature, and the slit-like through holes are arranged at equal intervals on the horizontal axis passing through the center of the shadow mask, and at increasing intervals on the vertical axis toward the periphery. Color picture tube.