JPS60157136A - Color picture tube - Google Patents

Abstract

PURPOSE:To improve color purity in an in-line dot type color picture tube by specifying the voltage applied to the frame of the shadow mask and the voltage applied to the inner sheid. CONSTITUTION:An in-line dot type color picture tube 29 is formed by containing a phosphor screen 31, shadow mask 32, frame 25 that supports the shadow mask 35, an inner sheild 36 supported on the frame 35. In addition, voltage Ef is applied to the frame 35 and voltage Es is applied to the inner shield 36. A convex lens 40 made of an equipotential surface 39 is formed between the frame 35 and the inner sheild 36 so as establish a relationship of Ef>Es between both. As a result, by adjusting Ef and Es to a proper value, the inclination between an electron beam trio 46 and a phosphor dot trio is corrected to be made to approach to a regular hexagon and color purity can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color picture tube, and more particularly to an in-line array electron gun, a perforated shadow mask with a circular electron beam passage hole, and a support for the shadow mask. Relating to improving the color purity of a color picture tube (hereinafter referred to as an inline dot type color picture tube) comprising at least a frame, an inner shield, and a phosphor screen consisting of a trio of phosphor dots corresponding to a circular electron beam passage hole. It is something.

[Technical background of the invention and its problems]

The most common color picture tube is a striped color picture tube, which is a combination of an in-line array electron gun, a phosphor stripe, and a phosphor stripe trio, which is mainly used for home use, but particularly high resolution is required. Inline point type color picture tubes are the mainstream color picture tubes for displays.

In the case of this inline dot type color picture tube, unlike the striped color picture tube, the landing characteristics in both the horizontal and vertical directions affect color purity, and the dot pitch is small to obtain high resolution, resulting in good color quality. Obtaining purity is difficult compared to striped color picture tubes.

Further, in an in-line dot type color picture tube, the phosphor screen is generally rectangular, and the arrangement direction of the in-line electron guns corresponds to its long axis, that is, the horizontal axis direction.

In this in-line dot type color picture tube, the three electron beams corresponding to the red, green, and blue phosphor dot trios passing through one circular electron beam passage hole in the shadow mask are mainly transmitted through the phosphor screen, which is spherical. Because of this, the horizontal axis (x
), the phosphor screen defined by the vertical axis (y) (
For example, in the vicinity of the diagonal axis end (A) of 11), the electron beam trio (1
6) will collide. Therefore, the phosphor dot trio (17) is also necessarily formed at a position where the electron beam trio (16) collides obliquely, and the relationship between the two is as shown in (18). In this case, the maximum value of the angle (θ) is approximately 5°.

As a method for improving the deterioration of color purity caused by the inclination of the electron beam trio (16) and the phosphor dot trio (17) mentioned above, for example, Japanese Patent Publication No. 19909/1982 and Japanese Patent Application Laid-Open No. 34640/1989 disclose As shown in FIG. 2, the horizontal alignment lines (24) of the circular electron beam passage holes (23) formed in the shadow mask (22) are formed into an appropriate barrel shape, and the vertical alignment lines (24) are formed into an appropriate barrel shape. 25) into an appropriate bottle cushion shape to obtain the shape shown in Fig. 2(b).
) As shown in FIG.
An electron beam trio (26) and a phosphor dot trio (27) shown with diagonal lines are formed at positions corresponding to FIG.
The relationship between the two is shown in (28). By adopting the structure as shown in FIG. 2, it is possible to improve the color purity.

However, this color picture tube has the following problems.

That is, in general, in an inline dot type color picture tube, the arrangement of the electron beams that impinge on the phosphor screen, which minimizes the possibility of mislanding, is a regular hexagonal arrangement, and the electron beam passage holes in the horizontal direction of the shadow mask are arranged in a regular hexagonal arrangement. Even if the color purity is improved by making the horizontal alignment lines (24) barrel-shaped, the barrel shape of the horizontal alignment lines (24) becomes stronger toward the periphery of the phosphor screen. As a result, the arrangement of electron beams on the phosphor screen has a large difference from the regular regular hexagonal arrangement, and the improvement in color purity at the periphery of the phosphor screen is no longer sufficient.

(Object of the Invention) The present invention has been made in view of the above-mentioned problems, and by adjusting the voltage applied to the frame and inner shield of an inline dot type color picture tube, a convex lens is inserted between the frame and the inner shield. The object of the present invention is to provide a color picture tube which can prevent deterioration of color purity due to inclination on the phosphor screen of an electron beam trio by the action of the convex lens.

[Summary of the invention]

That is, the present invention provides an in-line array electron gun, a shadow mask having a large number of circular electron beam passage holes, a frame supporting this shadow mask, an inner shield disposed close to this frame, and a circular electron beam In a color picture tube equipped with at least a phosphor screen consisting of a trio of phosphor dots corresponding to a beam passage hole, the relationship Ez>Es between the voltage Ef applied to the frame and the voltage ES applied to the inner shield. This is a color picture tube characterized in that it has a frame and an inner shield to form a predetermined convex lens.

[Embodiments of the invention]

Next, one embodiment of the color picture tube of the present invention is shown in FIGS. 3 to 7.
This will be explained using figures.

That is, the color picture tube (29) has a face plate (3).
0) A phosphor screen (31) is formed on the inner surface of the phosphor screen (31), and shadow masks (32) arranged at predetermined intervals on the phosphor screen (31) have a large number of circular electron beam passage holes (33). are provided regularly.

The skirt portion (34) of this shadow mask (32) is supported by a frame (35).
), an inner shield (36) is disposed in close proximity to the inner shield (36) and supported by, for example, a frame (35) via an insulator (not shown). Also, an inline array electron gun (38) is installed inside the neck (37), and this inline array electron gun (
The electron beam trios (46) emitted from the phosphor screen (38) are projected onto the phosphor dot trios of the phosphor screen (31) through circular electron beam passage holes (33). Furthermore, a voltage Ef is applied to the frame (35), and a voltage E is applied to the inner shield (36).
S is applied such that Ef>Es, and an equipotential surface (3) is created between the frame (35) and the inner shield (36).
A convex lens (40) consisting of (9) is formed.

With this structure, the electron beam trio (46) from the in-line electron gun (38) is subjected to a focusing effect in the area of the inner shield (36) and to a diverging effect in the area of the frame (35). Also, Ef>Es
By setting the applied voltage and the electron beam trio (
The force received from the equipotential surface (39) of the electron beam trio (46) is stronger in the area of the inner shield (36) where the electron beam trio (46) has a lower velocity.

That is, the electron beam trio (46) is connected to the phosphor screen (
31), the convex lens (40
), the electron beam directed toward the outside of the phosphor screen (31) is subjected to a force that is deflected toward the inside of the phosphor screen (31). Therefore, the electron beam trio (4) without the convex lens (40) shown in FIG.
6'), the change that the electron beam undergoes when it enters the electron beam passage hole becomes larger as the electron beam is located toward the outside of the phosphor screen (31). As a result, on the phosphor screen (31), the R electron beam is displaced in the direction of arrow (42) compared to the G electron beam, and the B electron beam is displaced in the direction of arrow (43) compared to the G electron beam. However, in the diagram, G
The electron beam is shown without displacement.

Therefore, by setting the strength of the convex lens (40) to an appropriate value while maintaining the relationship Ef>Es between the voltage Ef of the frame (35) and the voltage Es of the inner shield (36), as shown in FIG. As shown in (b), it is now possible to arrange the electron beam trios (46) almost in parallel on a straight line (X+) along the horizontal axis (X), and as shown in FIG. It has become possible to approximate a regular regular hexagon, and the margin against mislanding can be greatly improved. [Effects of the invention] As mentioned above, the voltage Ef applied to the frame and the voltage applied to the inner shield By setting the relationship Ef>Es to an appropriate value, it is possible to make the electron beam trio close to a regular hexagon, and as a result, the phosphor dot trio also becomes a regular hexagon. As a result, a color picture tube with good color purity can be provided.

[Brief explanation of the drawing]

Fig. 1 C13) is a plan view showing the phosphor screen surface of a conventional color picture tube, Fig. 1<i> is an enlarged explanatory view of the main part of the pass in Fig. 1, and Fig. 2 (b) is a plan view showing the phosphor screen surface of a conventional color picture tube. A plan view showing the shadow mask of the color picture tube in FIG. 2(b) is a plan view showing the shadow mask of the color picture tube in FIG.
), and FIGS. 3 to 7 are views showing one embodiment of the color picture tube of the present invention, and FIG. 3 is a sectional view,
Fig. 4 is an explanatory diagram showing a convex lens formed between the frame and the inner shield, Fig. 5 is an explanatory diagram showing the focusing and diverging effects of the electron beam by the convex lens, and Fig. 6 (a) is a case without the convex lens. FIG. 6(b) is an explanatory diagram showing the effect of a convex lens on the electron beam trio, FIG. 6(b) is an explanatory diagram showing the electron beam trio corrected by the convex lens, and FIG. 7 is an illustration showing the arrangement of the electron beam trio group on the phosphor screen. It is an explanatory diagram. 11, 31...phosphor screen 16, 46.46'...electron beam tray 17th...
Phosphor dot holes No. 22 and 32 Shadow masks 23, 33...Circular electron beam passage hole 35...Frame 36...Inner shield 38...Inline array electron gun 40...Convex lens Agent Patent attorney I Top - Male No. 1 Figure ta><b) Figure 2 (cL) Name: Color Picture Tube 3, Relationship with the Amendment Case Patent Applicant (307) Toshiba Corporation 4, Agent Address: 1.44 No. 4-41-11 Kamata, Ota-ku, Tokyo - Tsunoda Building Valid Patent Office phone number 736-3558 April 4, 1980 (Shipping date: April 24, 1980)
6. Column 7 for a brief explanation of the drawings in the specification to be amended, page 9, lines 16 to 17 of the specification of the contents of the amendment:
・, FIG. 1(a) is an enlarged explanatory view of the main part of FIG. 1(a), FIG. 2(b) is an enlarged explanatory view of the main part of FIG.
Enlarged explanatory diagram of the main parts of a), Penalty 21)...'' is corrected. that's all

Claims (1)

[Claims] An in-line array electron gun, a shadow mask having a large number of circular electron beam passage holes, a frame that supports the Shadrama and Suffu, an inner shield placed close to this frame, and the circular electron beam passage hole. In a color picture tube comprising at least a phosphor screen consisting of a trio of phosphor dots corresponding to the holes, a relationship E+>Es between the voltage Ef applied to the frame and the voltage ES applied to the inner shield. A color picture tube, characterized in that the frame and the inner shield form a predetermined convex lens.