JPS6337933B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dot-in-line type color picture tube, that is, a color picture tube in which electron guns are arranged in-line and a shadow mask has a small hole shape.

As has long been known, one of the problems with the landing characteristics of dot-in-line type color picture tubes is that
As stated in No. 50-19909, the pattern of the intersections of the three electron beams on the fluorescent screen does not form the densest structure.

Specifically, in FIG. 1, there is an in-line array of electron guns or electron beams in a direction that coincides with the longitudinal direction of the fluorescent screen 1.
Let the electron guns or electron beams for blue, green, and red be BB, BG, and BR, respectively. Also, as shown in the figure,
The direction of the inline arrangement is the X axis, and the direction perpendicular thereto is the Y axis. A in the figure is an enlarged view of a part of the hole arrangement of the shadow mask 2 corresponding to the fluorescent screen 1, and a broken line B connecting the holes closest to the hole 2a is shown.
coincides with the Y-axis direction. Here, the fluorescent screen 1 is usually formed on a glass panel, and furthermore,
Since the final picture tube is a vacuum container, it is formed into a spherical shape rather than an implosion prevention surface, and the shadow mask 2 facing the fluorescent screen 1 is also formed into a spherical shape.

FIG. 2 shows one hole 2 of the shadow mask (FIG. 1) 2 at each location of the fluorescent screen 1.
This is an exaggerated illustration of the characteristics of the pattern of the arrival points of the trio BB, BG, and BR of the electron beam that passed through a. FIG. 3 shows, as an example, a corner C in the first quadrant of the fluorescent screen 1 shown in FIG.
This is an enlarged view of the electron beam arrival point. In Figure 3, hole 2-1 of shadow mask 2 is shown.
(not shown, the same applies below), the trio of electron beams is B ₁ , G ₁ , R ₁ , and the hole 2 on the right side is
-2 are designated as B ₂ , G ₂ , and R ₂ . Also,
Hole 2-3 is located diagonally below the right side of hole 2-1.
They are B ₃ , G ₃ , and R ₃ . The problem here is that the broken line D made by B ₁ , G ₁ , R ₁ and the broken line E made by B ₂ , G ₂ , R ₂ are R ₁
B There is a difference in level between _{the two} . As a result, for example, in the upper right corner C of the fluorescent screen 1 shown in FIG. 2, the distance between B ₃ and R ₁ becomes abnormally narrow as shown in FIG. 3. This point is one of the disadvantages of the dot-inline type landing characteristics.

FIG. 4 is a diagram corresponding to FIG. 3 in an ideal case. The most dense structure referred to here refers to this state, which resembles a densely packed equilateral triangle. In this case, the fluorescent screen is used most effectively. In other words, the space factor is in good condition.

The above-mentioned Japanese Patent Publication No. 19909/1983 proposes to arrange the holes of the shadow mask as shown in FIG. 5 in order to eliminate the distortion corresponding to FIG. 3. It is true that the hole arrangement F of the above-mentioned Japanese Patent Publication No. 50-19909 can be brought close to the state shown in FIG. 4. However, the problem is that in this case, the peripheral mask hole pitch must be made smaller. That is, in the diagonal direction, the pitch must be reduced in both the X-axis and Y-axis directions. In other words, in order to increase the space factor shown in Figure 3, it is necessary to reduce the pitch in both the X and Y axes. The overall mutual distance becomes smaller. Another problem is that the pattern of the hole array F as shown in FIG. 5 is quite complicated and expensive when making a shadow mask.

On the other hand, due to this problem, for example,
As disclosed in JP-A-34640, JP-A-56-71256, and JP-A-56-41648,
Various hole arrays have been devised, but all of them are one-dimensional hole arrays and have not completely solved the problem.

This invention was made in view of the above-mentioned points, and it is possible to improve the hole arrangement of the shadow mask by two methods that are more effective.
It is a dimensional improvement pattern, and on a fluorescent screen, the minimum interval of the conventional problem (in the example in Fig. 3, R ₁
, G ₁ , B ₂ , B ₃ , and G ₃ ), the shadow mask is also easy to make, and the final result is a color picture tube that can more effectively increase the landing margin. This is what we are trying to provide.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 6 shows the hole arrangement of the shadow mask 2 in a flat state of a color picture tube according to an embodiment of the present invention. A hole 2a is bored at a pitch _a0 in the Y-axis direction from the center of the perforated portion of the mask corresponding to the center of the fluorescent screen 1 shown in FIG. On the X-axis, there are holes 2a located b _2N pitches away from the center in every even numbered row, and the pitch of the holes 2a in the Y-axis direction becomes parallel to the Y-axis as they move away from the X-axis. It is gradually getting smaller. The odd-numbered row is located midway between the even-numbered rows, and the hole positions in the Y-axis direction of the odd-numbered row are, for example, the Mth and M+1th holes in the even-numbered row (Pth row in the X-axis direction) and the holes in the next even-numbered row (P+2 ) is the height of the hole in the odd numbered row (P+1) surrounded by the Mth and M+1th holes.
It is approximately equal to the average of the hole positions. That is, the height of the first hole in the Y direction in the odd row near the X axis is approximately at a position of Y=1/2a ₀ . for example,
To explain the distribution of the holes in the nth row, they are located at a distance of N/2b _2N in the X-axis direction, the initial pitch in the Y-axis direction is an, and the m-th hole in the Y-axis direction The hole pitch is also an.

The vertical axis in FIG. 7A indicates the hole pitch in the Y-axis direction, and the horizontal axis indicates the coordinates of n hole positions in the X-axis direction. For example, the hole distribution may be expressed as the pitch of the nth row in the X-axis direction as follows.

a ₀ (1-K·n ² ) However, in the above formula, a ₀ is 0.320, and K is 7.59×10 ^-8 The unit is mm.

The vertical axis in Figure 7B is the pitch in the X-axis direction, and the horizontal axis is the
The coordinates of the hole position in the axial direction are shown. The present invention differs from conventionally proposed methods in this respect. That is, the pitch in the X-axis direction is also changed, and the pitch is set to gradually increase toward the edge of the screen.

For example, a specific formula is b _2N = b ₀ (1 + Kin ² ) where, in the above formula, b ₀ is 0.554, K ₁ is 3.06 × 10 ^-7 ,
The unit is mm. (When n = 700, b _2N = 0.637) To give a concrete example, for example, in a 20-inch size, as shown in Figure 8, a trio of electron beams
The inclination of B ₁ , G ₁ , and R ₁ with the X axis is about 3 to 6 degrees,
Generally speaking, "tilt of electron beam trio>tilt of corresponding phosphor trio", so a tilt of about 3 to 4 degrees is preferable. The hole arrangement according to FIG. 7A corrects this slope.

Figure 9A shows the third result obtained by correcting the above slope.
This is to explain how much the interval dimension between B ₃ and R ₁ in the figure has been modified. In the figure, the vertical axis indicates the dimension to be corrected (μm), and the horizontal axis indicates the angle of inclination to be corrected. As is clear from this figure, it is corrected by about 15 μm in accordance with FIG. 7A.

FIG. 9B is for explaining the improvement of the space factor by changing the pitch in the X-axis direction of FIG. 7B. In the figure, the vertical axis represents the percentage increase in the minimum dimension (%), and the horizontal axis represents the percentage increase in pitch (%). As is clear from this figure, the improvement ratio is 1:1 and is proportional to the pitch.
For example, the conventional pitch in the horizontal direction is 0.3×√3×1/2, and if the pitch is increased by 15% to 0.3×√3×1/2×1.15 as in this invention, there is a 15% advantage in the horizontal direction. , the dimensional relationship with the adjacent one is also advantageous by about 4% (about 7 μm in actual size).

Due to the above structure, when compared with Figure 5, the pattern in Figure 5 is formed by a "barrel" in the Y-axis direction and a "pink union" in the X-axis direction. In contrast, in the case of the present invention, the pattern is a "barrel" only in the Y-axis direction, and moreover, the X-axis direction is parallel to the Y-axis. Therefore, the hole arrangement of the shadow mask can be easily made, and the cost increase in the price of the shadow mask can be suppressed as much as possible.

In addition, in the above explanation, on the Y axis and any X=X
In the above explanation, the hole pitch in the Y-axis direction is always constant, but it goes without saying that the hole pitch does not necessarily have to be the same. It is important that the hole arrangement is always parallel to the Y-axis and that the pitch in the X-axis direction increases toward the periphery.

Furthermore, the color picture tube of this invention is often used to project characters, graphs, etc. In such cases, the pitch tolerance in the Y-axis direction is usually around ±25 μm (with a difference of 50 μm). ) is the limit. Also, in the X-axis direction, the limit is 20% increase compared to the center. For example, when the Y-axis direction is 0.300 in the densest structure, the pitch for the X-axis direction is approximately 0.52 mm, and when this value is selected for the center, the periphery increases by 20%, or approximately 0.62, which is the practical limit. I also found out that it is. Pituchi is
In high-resolution picture tubes around 0.300 mm, an improvement of about 7 μm represents a significant improvement, and not only increases the landing margin in the finished tube state, but also significantly improves the yield in making phosphor screens. This is something that can be greatly improved.

Here, the reason for limiting the tolerance in the Y-axis direction to ±25 μm and the 20% increase (1.2 times compared to the center) in the X-axis direction is to assume that the tolerance in the Y-axis direction is ±25 μm. The above, and also,
This is because if the pitch of X ₌

Although the hole pattern above was explained using a flat mask, it is actually formed into a dome shape, and then the relationship with the electron beam is investigated, and the results are fed back to the flat mask, so it is better to discuss the hole pattern using a flat mask. More practical.

To summarize this invention, when the direction of the in-line arrangement of the electron gun is defined as the X-axis, and the direction perpendicular to the X-axis including approximately the center of the fluorescent screen is defined as the Y-axis, the hole arrangement of the shadow mask in a flat state is defined as the Y-axis. The direction is always parallel to the Y axis, and the Y
Regarding the pitch in the axial direction, a ₀ is the pitch of the m-th hole counting from the X-axis on the Y-axis, and a 0 is the pitch of the m-th hole counting from the X-axis on the n-th parallel to the Y-axis. anm
Then, compared to the pitch a ₀ on the Y axis, this pitch anm satisfies a ₀ −50 (μm) ≦ anm < a ₀ , and the pitch anm increases as the distance from the Y axis increases. It is gradually getting smaller.

On the other hand, regarding the pitch in the X-axis direction, let b ₀ be the pitch at the center of the screen, and _b be the _pitch at arbitrary ₀ × 1.2, and the above b constitutes a flat mask that gradually increases in size as it moves away from the Y axis,
This flat mask was formed into a curved shadow mask.

In the above configuration, the pitch in the Y-axis direction is gradually decreased within a tolerance range of ±25 μm as the distance from the Y-axis increases, and the pitch in the X-axis direction is
The distance from the axis is gradually increased within the above 20% increase range, so while the horizontal resolution around the screen is slightly reduced, the tilting phenomenon of the electron beam can be corrected and the landing latitude can be increased.

Although there is a problem in that the horizontal resolution around the screen slightly decreases by gradually increasing the pitch of the X-axis, the feature of this invention is that it places more emphasis on securing landing latitude than horizontal resolution. There are characteristics.

In other words, in color picture tubes for displays, the electron beam generally extends in the X-axis direction due to deflection distortion, and the horizontal resolution around the screen always tends to decrease, and the hole pitch of the shadow mask 2 is small. It has two characteristics: the landing margin due to the tilt phenomenon of the electron beam is more critical than the horizontal resolution.

Therefore, it is extremely advantageous to increase the landing latitude even if the horizontal resolution is sacrificed a little in terms of eliminating fatal defects in color picture tubes.

Furthermore, in this embodiment, the hole arrangement of the shadow mask 2 is made into a two-dimensional (X-axis, Y-axis) improved pattern, so the minimum pitch of the holes around the screen can be increased and the space factor can be improved. effective.

Since the present invention has the above-described configuration, the distance between the electron beams on the fluorescent screen is practically the maximum in all directions, so that the space factor in two directions can be improved.
Moreover, by slightly sacrificing the horizontal resolution around the screen, a large landing margin can be obtained with a minimum pitch change range, and a low-cost color picture tube with which shadow masks can be easily created is provided. be able to.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the relationship between the in-line arrangement of the electron gun and the hole arrangement of the shadow mask, and the X and Y axes.
FIG. 2 is a diagram explaining that an electron beam is tilted on a fluorescent screen, FIG. 3 is a diagram explaining details of FIG. 2, and FIG. 4 is a diagram corresponding to FIG. 3 in an ideal case. FIG. 5 is a diagram showing a hole arrangement of a shadow mask for eliminating distortion corresponding to FIG. 3, FIG. 6 is a diagram showing a hole pattern of a shadow mask of a color picture tube according to an embodiment of the present invention, and FIG. A is a diagram showing pitch changes in the Y-axis direction of the present invention, FIG. 7B is a diagram showing pitch changes in the X-axis direction, FIG. 8 is a diagram explaining the tilt of the electron beam trio, and FIG. 9 FIGS. 7A and 7B are diagrams showing the degree to which the distance between adjacent beams has been improved by FIGS. 7A and 7B, respectively. 1... Fluorescent screen, BB, BG, BR... Electron gun, 2... Shadow mask, 2a... Hole. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. The direction of the inline arrangement of the electron guns is the X axis,
When the Y-axis is defined as the perpendicular direction that includes approximately the center of the fluorescent screen, the hole arrangement of the shadow mask in a flat state is always parallel to the Y-axis, and the pitch in the Y-axis direction is , the m-th hole pitch on the Y-axis counting from the X-axis is a ₀ , and the pitch of the m-th hole on the Y-axis counting from the
When the pitch of each hole is defined as amm, this amm
is compared to the pitch a ₀ on the Y axis, a ₀ −50 (μm) ≦ anm < a ₀ , and the above a m gradually becomes smaller as it moves away from the Y axis, and , regarding the pitch in the X-axis direction, let b ₀ be the pitch at the center of the screen, and _b be the _pitch at arbitrary X=X _. ×1.2, and the above b constitutes a flat mask that gradually increases in size as it goes away from the Y axis, and a color image receiving device comprising a shadow mask formed by forming this flat mask into a curved shape. tube.