JP2002008556A - Color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color picture tube which prevents the occurrence of color shift, caused by the fact that electron beam hits not only the objected phosphor, but also hits another phosphor due to the effect of terrestrial magnetism or the like, by improving the permissibility of another color hitting by differentiating the diameter of holes on shadow mask through which electron beam passes. SOLUTION: At a shadow mask 9 arranged in a face panel 11, the diameter of an electron beam passing hole 22 is differentiated from that of either one of adjacent holes 22, preferably between the hole on a row in even number and the hole on a row in odd number.

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 which has an increased margin for other color hits of an electron beam, which is affected by geomagnetism or external magnetism.

[0002]

2. Description of the Related Art In general, a color picture tube comprises a glass face panel, a glass funnel-shaped funnel joined to the face panel, and a glass cylinder connected to a small end of the funnel. It has an envelope consisting of a neck with a stem, and a stem is welded to the end of the neck.

[0003] Then, three electron beams emitted from an electron gun arranged in the neck are deflected by a deflection yoke mounted on the outside of the funnel, and a fluorescent light provided on the inner surface of the face panel via a shadow mask. A color image is displayed by scanning the body screen in the horizontal and vertical directions.

That is, as shown in FIG. 3, a funnel 32 made of a glass material and welded through a frit glass is provided on a substantially rectangular face panel 31 made of a glass material. In the neck 33,
An electron gun 35 that emits three electron beams 34 for red (R), blue (B), and green (G) is attached to a stem 36 that is welded to a neck 33.

[0005] An electron beam 34 emitted from the electron gun 35 is deflected by a deflection yoke 37 mounted outside the funnel 32, and is fixed to a frame 38 mounted on the inner wall of the face panel 31. Through 39, it is projected on the R, G, B three-color phosphor screen 40 formed on the inner surface of the face panel 31,
It is configured to display a color image.

The shadow mask 39 has a mask body 41 made of a low-carbon-rolled steel sheet or a low-thermal-expansion material such as an iron-nickel alloy. The mask body 41 has a horizontal direction (MPh) and a vertical direction (MPv). ) At a predetermined pitch (M
In P), a plurality of electron beam passage holes 42 are formed by using a photo etching method or the like.

The shadow mask 39 is also used as a photomask in an exposure process for forming a three-color phosphor screen 40 on the inner surface of the face panel 31. In operation, a predetermined phosphor screen 40 to be illuminated with an electron beam It also has a color selection function for causing the projection 34 to strike.

[0008] Even if the shadow mask 39 extends along the horizontal axis or the vertical axis toward the center and outward of the effective diameter, the diameters of the adjacent electron beam passage holes 42 are limited over the entire surface of the shadow mask 39. Generally, they are formed substantially uniformly. In some cases, there may be a slight difference in the hole diameter between the central portion and the peripheral corner portion, but even in such a case, the hole diameter of the electron beam passage hole 42 within a predetermined single small area includes: Even in this case, the pore size is considered to be uniform since there is little difference.

The arrangement of the electron beam passage holes 42 is M
It is generally set by a mathematical expression composed of functions of Ph and MPv, and uses to be used are classified according to the type of resolution. For example, for a monitor of a recent personal computer, roughly two types of 0.26MP and 0.28MP are adopted. Further, the MPv of the shadow mask 39 of the color picture tube for the monitor is used.
Is set as MPv = about 250 μm as a general design value. The deflection frequency supplied to the deflection yoke 37 is also 31.5 KHz to 94 KHz.
The multi-scan method in which the processing is performed by a single personal computer has become mainstream.

In this case, the scanning line on the monitor side is 600
It can be easily changed within the range from 1 to 1200 lines, and the moiré characteristics and the like, which will be seen on the monitor screen depending on the used deflection frequency, are determined by the color of the phosphor screen 40 which emits light from the color picture tube. It depends on the vertical positional relationship (Pv) between the colors.

On the other hand, the electron beam 34 that has passed through the shadow mask 39 strikes the phosphor screen 40. In the phosphor screen 40, three-color phosphor dots 43 of R, G, and B are arranged in a horizontal direction (Ph) and a vertical direction (Pv) at a predetermined pitch (P).
The three spaces are covered with a black light absorbing layer 44.

The Pv of the phosphor dots 43 formed on the inner surface of the face panel 31 is used in the exposure process because the shadow mask 39 and the phosphor screen 40 are arranged at a predetermined interval. Shadow mask 3
The Pv value is about 260 μm, which is larger than the MPv of No. 9.

By the way, when the electron beam 34 is deflected by the deflection yoke 37, for example, the moiré characteristic means that the brightness distribution between scanning lines and the brightness distribution that occur between the scanning lines and the shadow mask 39 depend on the deflection frequency. The electron beam 34 hits the phosphor screen 40 formed on the inner surface of the face panel 31, and refers to luminance unevenness on the screen caused by the emission luminance integrated by Pv. Will look like

Since the moiré characteristic is also affected by the matching with the monitor to be driven, if a monitor or the like is designed based on a color picture tube for which specifications have been set first, the moiré characteristics will be affected at this design stage. In many cases, the moiré characteristics are determined. If, for example, color picture tubes with different Pvs are used in the same monitor halfway, there is a risk that the moiré characteristics may be degraded. The design cannot be changed in the middle stage on the side, and in this case, it is necessary to cope with this by redesigning the monitor side corresponding to the color picture tube to be adopted.

Here, a more detailed description will be given with reference to FIG. 4 which shows a part of the phosphor screen 40 in an enlarged manner.

If Pv is constant, the distance between the phosphor dots 43 in the vertical, horizontal, and vertical directions is
3, one electron beam 34 having a diameter R1 indicated by a broken line in the drawing (in FIG. 4, a case where an R dot having a diameter R2 indicated by a solid line in the drawing is shown) is generated. Assuming that the distance La to Lf until the phosphor dot 43 (G, B) of the other color adjacent to the dot of R is vertically and horizontally adjacent to each other, the other color hitting margin L is defined as the other color hitting margin L. Is the electron beam passage hole 4 of the shadow mask 39
2, the size R1 of the electron beam 34 projected on the phosphor screen 40 formed on the inner surface of the face panel 31 and the size R2 of the dot 43 described above.

The electron beam 34 involved in the color margin L is at least affected by the natural magnetic field (geomagnetism) of the earth and the magnetic field generated from a monitor power supply, a high-voltage circuit, and the like. , The probability of occurrence of color misregistration caused by hitting the dot 43 of another color that is not the target varies.

Furthermore, in recent years, with the progress of higher luminance (higher current) and the development of software such as personal computers, there are more opportunities to use the screen of a color picture tube as a white screen. When the color picture tube is operated in such a situation, the shadow mask 39
Screen 40 through the electron beam passage hole 42
Reaches the shadow mask 3 on the way.
9 collides with the mask body 41 of the
5 is 1/3 or less of the electron beam 34 emitted from the electron beam 5.

As a result, the mask body 41 is heated by the collision of the electron beam 34 and the phosphor screen 4 is heated.
Mask doming swelling in the zero direction (so-called purity drift) occurs, and this mask doming cannot be ignored, and this mask doming also causes a color shift.

Under these circumstances, in order to improve the margin L for other color printing, the size of the dot 43 or the size of the electron beam 34 is reduced, or the MPv and MPh of the shadow mask 39 are changed. A possible method is to increase the distance La to Lf before hitting another color. However, as described above, the change in Pv involves redesign of the monitor, the size of the dot 43 and the size of the electron beam 34. Since reducing the size leads to a decrease in the emission luminance, the only way to secure a constant luminance is to increase the beam current, which results in an increase in purity drift. become.

[0021]

As described above, the electron beam emitted from the electron gun in the color picture tube is deviated from a predetermined color by the magnetic field due to the terrestrial magnetism and the magnetic field generated from the monitor power supply. In addition, an electron beam hits adjacent dots of different colors, causing a color shift and deteriorating image quality.

The present invention has been made in view of such a problem, and has been made in consideration of any one of the adjacent electron beam passing holes of the shadow mask, more specifically, the diameter of the electron beam passing hole of the shadow mask. Is an even column and an odd column, so that even column> odd column or even column <odd column,
The distance La to Lf between the vertically adjacent phosphor dots can be increased without changing Pv, and even if the electron beam emitted from the electron gun in the color picture tube is affected by the magnetic field, other unintended objects can be obtained. An object of the present invention is to provide a color picture tube capable of improving a margin L before hitting a color, thereby preventing color misregistration.

[0023]

SUMMARY OF THE INVENTION The present invention provides a rectangular face panel, a funnel connected to the face panel, a three-color phosphor screen formed on the inner surface of the face panel, and A shadow mask disposed in the face panel facing the phosphor screen at a predetermined interval; and electrons arranged in the funnel that emits an electron beam that passes through the shadow mask and strikes the phosphor screen. Equipped with a gun,
The shadow mask is provided with a plurality of electron beam passage holes for passing an electron beam, and at least one of the adjacent electron beam passage holes is arranged so that the diameter of at least one electron beam passage hole is different. Is a color picture tube.

The electron beam passage holes may have different diameters between electron beam passage holes adjacent to each other in the vertical direction, or have the same hole diameter in each column direction, and have the same diameter between the odd and even rows. The hole diameters are different from each other.

With this configuration, the distance Pv between adjacent phosphor dots of the three-color phosphor formed on the inner surface of the face panel can be increased without changing the distance.
An object of the present invention is to provide a color picture tube that can increase the margin for other color L and prevent color shift affected by a magnetic field.

[0026]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a color picture tube which is one embodiment of the present invention. This color picture tube has a funnel-shaped funnel 12 made of a glass material which is welded via frit glass to a substantially rectangular face panel 11 made of a glass material. An electron gun 15 that emits three electron beams 14 for red (R), blue (B), and green (G) has a stem 1 welded to a neck 13.
6 is attached.

The electron beam 14 emitted from the electron gun 15 is deflected by a deflection yoke 17 mounted on the outside of the funnel 12 and fixed on a frame 18 mounted on the inner wall of the face panel 11. 19, it is projected on the R, G, B three-color phosphor screen 20 formed on the inner surface of the face panel 11,
It is configured to display a color image.

The shadow mask 39 has a thickness of 0.1 m.
The horizontal (MPh) and vertical (MPh) directions are applied to a mask body 41 made of a low-carbon rolled steel sheet such as aluminum-killed steel having a diameter of about m to 0.3 mm or a low-thermal-expansion material such as an iron-nickel alloy.
In v), a plurality of electron beam passage holes 42 are formed at a predetermined pitch (MP) by using a photo-etching method or the like.

The diameter of the electron beam passage hole 22 of the shadow mask 19 is changed between an odd-numbered row and an even-numbered row, and the hole diameter is changed, for example, in an even-numbered row. The hole diameter of the odd-numbered rows or the hole diameter of the even-numbered rows <the hole diameter of the odd-numbered rows is set, and the electron beam passage holes 22 belonging to the same row are set to the same diameter.

The shadow mask 19 is also used as a photomask in an exposure process for forming a three-color phosphor screen 20 on the inner surface of the face panel 11, and a predetermined phosphor screen 20 to emit light during operation.
In addition, it also has a color selection function for causing the electron beam 14 to strike.

The electron beam 14 having passed through the shadow mask 19 formed as described above is applied to the phosphor screen 2.
Fire at 0. This phosphor screen 20 has R, G,
The three-color phosphor dots 23 of B are arranged at a predetermined pitch (P) in the horizontal direction (Ph) and the vertical direction (Pv), and a black light absorbing layer 24 is provided between the phosphor dots 23. Covered.

The area of the phosphor dot 23 is changed in accordance with the diameter of the electron beam passage hole 22 provided in the above-described shadow mask 19. The dot diameter of the even-numbered rows> the dot diameter of the odd-numbered rows or the dot diameter of the even-numbered rows <the dot diameter of the odd-numbered rows is set.

A more detailed description will be given with reference to FIG. 2 showing a part of the phosphor screen 20 on an enlarged scale.

The Pv of the phosphor dots 23 formed on the inner surface of the face panel 11 is, for example, 260 μm. Since the shadow mask 19 and the phosphor screen 20 are arranged at a predetermined interval, the Pv Mask 1
The Pv value is larger than Pv of 9, for example, 250 μm.

In other words, the irradiation state of the electron beam 14 during operation, which is projected on the phosphor screen 20 on the inner surface of the face panel 11 through the shadow mask 19, is equal to the diameter R.
1, the dot diameter of the phosphor dots 23 actually formed by the exposure apparatus is in the state of the diameter R2 shown by the solid line, and is smaller than the dot diameter R2 of the phosphor dots 23. The beam 14 is formed so that the beam diameter R1 is larger.

Here, when Pv is constant, the distance between the phosphor dots 23 in the vertical and horizontal directions changes depending on the dot size of the phosphor dots 23, and one electron beam having a diameter R1 indicated by a broken line in the drawing. Reference numeral 14 (in FIG. 2, a case where an R dot having a diameter R2 indicated by a solid line is shown) is a phosphor dot 23 (G, B) of another color adjacent to the R dot. Distance La to L
If f is the margin L for other color, the margin L for other color is
Is determined by the size R1 of the electron beam 14 projected on the phosphor screen 20 formed on the inner surface of the face panel 11 through the electron beam passage hole 22 of the shadow mask 19 and the size R2 of the phosphor dot 23 described above. In the present invention, the distance between the phosphor dots 23 vertically adjacent to each other without changing Pv, ie, the shadow mask 1
9 by changing the diameter of the electron beam passage holes 22 for each row,
For example, by setting the hole diameter of the even-numbered row> the hole diameter of the odd-numbered row, or the hole diameter of the even-numbered row <the hole diameter of the odd-numbered row, and by setting the hole diameters in the same row to be constant, La to Lf is widened. Phosphor dots 23 formed by an exposure device
, And the beam diameter R1 of the electron beam 14 projected on the phosphor screen 20 on the inner surface of the face panel 11 through the shadow mask 19 can be reduced.

Here, Pv is 260 μm, and Ph is 2
When the margin L of the other colors was measured between the conventional example and the present invention at 30 μm, the results shown in Table 1 were obtained.

[Table 1] In the case of the conventional example, the dot size of the phosphor dots 43 is set to 1
When the electron beam size is set to 00 μm and the electron beam size is set to 160 μm, as shown in Table 1, the other color hitting margins L between the dots 43 are 23 Lc and Lf adjacent to each other on the same column.
μm, and La, L between the phosphor dots 43 on the other rows.
b, Ld, and Le were each 21 μm. These values are shown in parentheses in Table 1 as the reference value 1.00.

On the other hand, in the case of the present invention, one of the even-numbered rows and the odd-numbered rows has the same size as the conventional one, and the dot size of the phosphor dots 23 in the other row is 95 μm.
m, the beam size of the electron beam 14 is 152 mm, and in the case of Example 1 in which both the dot and beam size in the other row are set smaller than in the conventional case, Lc and Lf are 3
2 μm, other La, Lb, Ld, Le
It was 0 μm. This indicates that Lc and Lf exhibit a multi-color margin allowance L of 1.39 times, and La, Lb, Ld and Le 1.55 times that of the related art.

Similarly, in Example 2 of the present invention in which the dot size of the phosphor dots 23 was 90 μm and the electron beam size was 144 μm, Lc and Lf were 41 μm, and L
a, Lb, Ld, and Le each became 39 μm. These Lc and Lf are 1.78 times higher than those of the prior art, and La and Lf.
For b, Ld, and Le, it is possible to set the other color hitting margin L to 1.86 times.

The size of the phosphor dots 23 is set to 85 μm.
m, Example 3 of the present invention in which the electron beam size was 136 μm
In the case of the above, Lc and Lf are 50 μm and other L
a, Lb, Ld, Le are 48 μm, and Lc, Lf are 2.17 times as compared with the conventional one, and other La, Lb, Ld, Le
As a result, a margin L of 2.29 times other colors could be secured.

From Table 1, in the case of Example 1 of the present invention,
By reducing the phosphor dot size by 5 μm,
The effect is 55 times, and in Example 2, the phosphor dot size is 1
By reducing the size of the phosphor dot by 0 μm and 1.86 times, and by reducing the phosphor dot size by 15 μm as in Example 3, approximately 2.
It is possible to improve the margin L of other colors by three times.

By reducing the diameter of the electron beam passage hole 22 of the shadow mask 19, there is a concern that the brightness of the whole screen may be reduced. By mixing the electron beam passage holes 22 having different diameters of the electron beam passage holes 22 constituting the mask 19, it is possible to configure the structure without significantly affecting the reduction in luminance of the entire screen. Rather, preventing the color misalignment due to the electron beam 14 hitting the phosphor dot 23 of another color other than the intended purpose can further reduce the influence on the screen quality.

Further, toward the peripheral corner direction with respect to the screen center, for example, the size of the electron beam passing holes 22 in the even-numbered rows of the shadow mask 19 is reduced, and the size of the electron beam passing holes 22 in the odd-numbered rows is gradually increased. , The moiré phenomenon can be made less noticeable or the brightness distribution can be made constant. If the hole diameter of the electron beam passage holes 22 is optimally arranged over the entire screen, the center of the screen and the peripheral corners can be obtained. Not only the part,
It is possible to cope with such moiré phenomena and uniform luminance distribution.

Further, in the above description, the shadow mask 19
And the phosphor dots 23 have been described as being of the dot type. However, even in the case of the stripe type, similar effects can be expected in the horizontal direction, and the present invention is not limited to these embodiments. It goes without saying that various applications and modifications are possible.

[0046]

According to the present invention, without changing the distance between the phosphor dots, the diameter of the electron beam passage holes of the shadow mask can be reduced to at least one, preferably even, number of adjacent electron beam passage holes. By setting the relationship of odd-numbered columns or even-numbered columns <odd-numbered columns, it is possible to prevent color hits caused by a magnetic field and purity drift, to improve color unevenness, and to improve image quality. A possible color picture tube can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for explaining a configuration of a color picture tube according to the present invention.

FIG. 2 is an enlarged plan view showing a part of a shadow mask constituting the color picture tube.

FIG. 3 is an explanatory diagram for explaining a configuration of a conventional color picture tube.

FIG. 4 is an enlarged plan view showing a part of a shadow mask constituting the color picture tube.

[Description of Signs] 11: Face panel 12: Funnel 14: Electron beam 15: Electron gun 19: Shadow mask 20: Phosphor screen 22: Electron beam passage hole

Claims (3)

[Claims] 1. A rectangular face panel, a funnel connected to the face panel, a three-color phosphor screen formed on an inner surface of the face panel, and a predetermined distance from the phosphor screen A shadow mask disposed in the face panel facing the electron gun, and an electron gun disposed in the funnel that emits an electron beam that passes through the shadow mask and strikes the phosphor screen. The mask is provided with a plurality of electron beam passage holes for passing an electron beam, and at least one of the neighboring electron beam passage holes is arranged so that the diameter of at least one electron beam passage hole is different. Color picture tube. 2. The color picture tube according to claim 1, wherein said electron beam passage holes have different diameters between electron beam passage holes which are vertically adjacent to each other. 3. The color picture tube according to claim 1, wherein the electron beam passage holes have the same hole diameter in each column direction, and have different hole diameters between odd-numbered rows and even-numbered rows. .