JPH083977B2 - Shead mask type color CRT - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a shadow mask type color cathode-ray tube using a flat-plate tensioned flat surface, that is, a flattening type shadow selection mask for color selection. .

[Prior Art] FIG. 7 is a block diagram of a conventional flat-tension type shadow mask type color cathode-ray tube disclosed in, for example, JP-A-61-80735.
1) is a face plate using flat glass, (12)
Is a skirt portion, and the face plate (13) is constituted by welding the face plate (11) and the skirt portion (12) through the fritted glass (3) as shown in FIG. (4) is the funnel part,
A neck portion (5) containing an electron gun (not shown) is integrally connected, and the funnel portion (4) and the neck portion (5) are integrally formed through the frit glass (14). It is welded to the skirt (12) of (13). (2) is a flat-shaped color selection sheer mask, which is arranged so as to face the fluorescent screen (11A) formed on the inner surface of the face plate (11) and is uniformly tensioned in the planar direction. A large number of electron beam passage holes (2a) are formed by etching or the like.

 Next, the operation of the above configuration will be described.

Three electron beams of red, green, and blue (hereinafter referred to as R, G, B) emitted from an electron gun (not shown) pass through the electron beam passage hole (2a) of the shadow mask (2),
The fluorescent plate (11A) on the inner surface of the face plate (11) collides with the fluorescent plate to emit a predetermined fluorescent substance. At this time, a part of the electron beam collides with the sheer dough mask (2), and the sheer dough mask (2) is heated and heated to thermally expand. However, since the sheer dough mask (2) is applied with a tension in the plane direction. By setting the tension and the thermal expansion amount to be substantially equal to each other, the thermal expansion is absorbed by the tension relaxation to suppress the deformation of the shadow mask (2) and the electron beam landing error is suppressed. It is possible to obtain a screen that is easy to see with very few.

[Problems to be Solved by the Invention] In the conventional shadow mask type color CRT configured as described above, the face panel (13) holds the flat plate face plate (11) and the shadow mask (2) therein. Since it is divided into the skirt part (12) and processed, the face plate (11) generally made of glass and the skirt part (12) are individually processed, resulting in poor productivity, and the face plate (11) and Since a process of welding the skirt (12) is required, it is difficult to avoid problems such as yield, reliability of product accuracy, and cost.

In addition, it has been practiced in the past to integrally mold a panel having a flat face and a skirt with a press, but in this case, the swath phenomenon, which is the fate of glass molding, cannot be avoided, so the face can be accurately formed. There was a drawback that it could not be flattened.

The present invention has been made to solve the above-mentioned problems, and it is possible to integrally mold by a press to achieve improvement in productivity, yield, and manufacturing precision, and a shadow mask capable of obtaining a high-quality image. The purpose is to provide a color cathode ray tube.

[Means for Solving Problems] In a shadow mask type color cathode-ray tube according to the present invention, the inner surface of the face plate has a radius of curvature in a diagonal axis direction on the screen> a radius of curvature in a horizontal axis> a radius of curvature on a vertical axis. While forming the face plate and the skirt portion integrally so as to form a curved surface having a relationship,
Absorbing the gap between the center portion and the peripheral portion of the face plate and the flat shed mask, the pitch of the phosphor dots provided on the inner surface of the face plate is almost the same as the pitch in the center portion over the entire screen. As described above, the pitch of the electron beam passage hole of the shutter mask is configured to be continuously small as it goes from the central portion of the screen to the peripheral portion.

[Operation] In the present invention in which a flat-plate shear dough mask is used as a premise, the face plate inner surface is made to satisfy the relationship of a radius of curvature in the diagonal axis direction on the screen> a radius of curvature in the horizontal axis direction> a radius of curvature on the vertical axis. By forming a curved surface close to a flat surface, it is possible to accurately perform integral molding by pressing, including the skirt portion, in a state without a swirl phenomenon. Further, since the fluorescent surface on the inner surface of the face plate is a curved surface, the facing distance between the flat shed mask and the fluorescent surface is different between the central portion and the peripheral portion in each axial direction on the screen. By changing the pitch of the electron beam passage hole of the shear mask according to this difference in spacing, the spacing of the phosphor dots and the screen pitch proportional thereto can be adjusted to a range that is not unnatural in practical use. .

[Embodiment] An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a shadow mask type color cathode-ray tube according to an embodiment of the present invention. In FIG.
The same configurations as those of the conventional example shown in the figure are designated by the same reference numerals,
The detailed description thereof is omitted.

In the shear dough mask type color cathode ray tube, the face panel (13) is formed by integrally molding the face plate (11) and the skirt portion (12) with a press. As shown in FIG. 2, the inner surface of the face plate (11) of the integrated face panel (13) has a radius of curvature of each axis on the screen at a radius of curvature on the diagonal axis (RD)>
Curvature radius on horizontal axis (RH)> Curvature radius on vertical axis (RV)
It is formed on a spherical surface, which is one of the curved surfaces satisfying the relationship of, and the fluorescent surface (11A) is adhered and formed on this spherical surface.

Then, the pitch of the electron beam passage hole (2a) of the shutter mask (2) is the screen, that is, the face plate (1).
As the distance from the central part to the peripheral part of 1) is gradually reduced so that the relative size of the inner surface of the face plate (11) to the fluorescent screen (11A) satisfies a predetermined condition. The configuration will be described in detail below.

That is, in the cathode ray tube shown in FIG.
-The three electron beams (30) of B pass through the common hole (2a) of the shadow mask (2), and are correctly combined with the fluorescent surface (11A) on the inner surface of the face plate (11) to make the dots (21). Form.

An example of a normal dot type phosphor screen and an in-line beam type cathode ray tube will be described. The relationship between the phosphor dot (21) and the screen pitch is as shown in FIG. It is necessary to arrange the R, G, and B phosphor dots (21) so that they are correctly aligned, and the intervals between the R, G, and B phosphor dots (21). (L) needs to be one-third of the horizontal triopitches (PH). Therefore, the screen pitch (P
S), RG of electron beam (30) emitted from electron gun
・ If the spacing (S) of each beam of B, the size of the cathode ray tube, the deflection angle, etc. are determined, the dimension (L) from the deflection center of the electron beam to the shadow mask (2), the shadow mask (2) and the face plate (inevitably 11) Inner phosphor screen (11A)
Dimension (Q) is determined. R at the center of the screen at this time
The interval (d0) between the G and B phosphor dots is This is the case where the shear mask (2) and the inner surface of the face plate (11) face each other in parallel, and the shear mask (2) is flat and the inner surface of the face plate (11) is spherical. In this case, if the value of (d) is not reduced along the periphery, it is a basic condition for designing a cathode ray tube. Can not meet the conditions of.

Therefore, in order to obtain the requirements for satisfying this condition, Fig. 5 summarizes the examination results in the case of a flat-screen cathode ray tube having a diagonal outer shape of 15 inches and a screen pitch of 0.31 mm.

Each condition at this time is: L = 184.5mm Q = 6.5mm S = 5.1mm Screen size: Diagonal = 175mm Horizontal = 130mm Vertical = 100mm Radius of curvature of face plate inner surface R 10,000mm, 15,000mm, 20,000mm Fig. 5 As is clear from the above, in this combination, in the case of R 10,000 mm on the inner face of the face plate, the value of (d) is the worst point at the diagonal end of the screen, which is 25% smaller than the center. Is proportional to the screen pitch (PS), so the screen pitch is 25% to the center as well.
It is also necessary to make it smaller, and if the R of the face plate inner surface is 15,000 mm, the reduction amount is 15%, and if R is 20,000 mm, the reduction amount is 10%. Be done.

On the other hand, from the viewpoint of press molding of glass, when the inner surface of the face plate is flat, there is a problem that it is difficult to obtain flatness accuracy due to a swirl phenomenon due to the pressing die of the press, and it is desirable to add R to the inner surface. The upper limit of R is about 20,000 mm.

For this reason, from the results of the examination of the previous example, it is desirable that the radius R of the inner surface of the face plate in the case of a 15-inch CRT is about 15,000 mm to 20,000 mm.

That is, the distance (d) between adjacent phosphor dots is the center / peripheral ratio. It is necessary to define the amount of change in the inner surface R of the face plate and the hole pitch of the shadow mask so that the combination satisfies the above condition.

In addition, even if the screen size is the same, the relationship between the above (L) and (Q) changes if the screen pitch is different. For example, if the screen pitch becomes large, (S) becomes constant and (Q) becomes large. The ratio of the center and the periphery of the body dot interval tends to be improved.

Since the phosphor dot interval (d) and the screen pitch (PS) are in a proportional relationship from the above formula (2), the ratio between the center and the periphery of the dot interval (d) used in the description so far is the same as the screen pitch. (PS) can be replaced by the ratio of the center to the periphery.

That is, assuming that the central screen pitch (PS0) and the peripheral screen pitch (PS1) are: Becomes

In the above description, the case where the curved surface of the inner surface of the face plate (11) is a spherical surface having a uniform radius of curvature over the entire surface has been described, but if a certain condition is satisfied, the vertical axis, the horizontal axis, the pair of It can be configured with different radii of curvature in the direction of the angular axis. Generally, the screen shape of these cathode ray tubes is a rectangle with an aspect ratio of 4: 3 or 16: 9. Therefore, in the glass bulb as the vacuum container, the stress plate has a maximum stress point on the rectangular axis, that is, the vertical axis or its vicinity, which is the closest distance from the central axis of the tube.

Therefore, in the case of using a flat shed mask as a premise as in the present invention, it is desirable to bring the face plate as close to a plane as possible, and the radius of curvature of the face surface is as small as possible within a range not impairing the flatness. It is better to do. That is, regarding the radius of curvature of the face plate, it is desirable to reduce the radius of curvature of a portion where a large amount of stress is applied during vacuum.

Therefore, in order to balance the flatness and strength of the face plate, the inner surface of the face plate must satisfy the relationship of the radius of curvature on the screen in the direction of the diagonal axis> the radius of curvature in the direction of the horizontal axis> the radius of curvature on the vertical axis. To form a curved surface close to a flat surface.

That is, the radius of curvature (RH) of the vertical axis with the smallest distance from the center of the screen is minimized, and the radius of curvature of the diagonal axis (R
D) is the largest compound curved surface. In this case, reduce (RH) of the face plate inner surface in the vertical axis direction,
Providing a difference in wall thickness from the outer surface not only creates a flutter on the outer surface, but also reinforces the vertical axis, which has the weakest strength as a cathode ray tube, and is a very effective means.

The radius of curvature of each axis on the screen (RD), (RH), (R
It is also possible to make a difference in V) so that each axis is combined so as to satisfy the above formula (5).

For example, in Figure 6, the radius of curvature (RV) of the vertical axis is 10,000.
mm, the radius of curvature (RH) of the horizontal axis is 15,000 mm, and the radius of curvature (RD) of the diagonal axis is 25,000 mm. It goes without saying that the middle part of each of these axes needs to be able to smoothly connect the curved surfaces of each axis.

[Advantages of the Invention] As described above, according to the present invention, the inner surface of the face plate satisfies the relationship of the radius of curvature in the diagonal axis direction on the screen> the radius of curvature in the horizontal axis direction> the radius of curvature on the vertical axis. By forming a curved surface close to a flat surface like this, it is possible to integrally form a face panel composed of a face plate and a skirt portion by a press without causing a swirl phenomenon. It is possible to improve productivity, process yield, and manufacturing accuracy. In addition, by using a flat plate-shaped shearing mask to which tension is applied in the plane direction, thermal expansion of the shearing mask is absorbed by tension relaxation to suppress doming of the shearing mask and the landing error can be greatly reduced. it can. In addition, the difference in the facing distance between the central part of the screen and the peripheral part, that is, the unnatural arrangement of the phosphor dots, which occurs with the combination of the curved surface of the face plate and the flat shadow mask, It is possible to obtain a bright and easy-to-see screen by correcting it by adjusting the pitch of the electron beam passage hole and making a simple improvement in manufacturing process.

As described above, it is possible to provide a color cathode ray tube having excellent image quality and cost.

[Brief description of drawings]

FIG. 1 is a partially cutaway front view of a shadow mask type color cathode-ray tube according to an embodiment of the present invention, FIG. 2 is an enlarged cross-sectional view of an essential part, and FIG. 3 is a diagram illustrating the relationship between a fluorescent screen dot and a screen pitch. FIG. 4 and FIG. 4 are explanatory views of the configuration of the main part, and FIG.
Fig. 6 is a graph showing the correlation between the spherical radius of the face plate and the phosphor dot spacing in the case of a 15-inch, 0.31 mm screen-pitch CRT. Fig. 6 shows the radius of curvature of each axis on the screen. FIG. 7 is a graph showing the correlation between the spherical radius of the face plate inner surface and the phosphor dot spacing in the case of a cathode ray tube. FIG. It is an expanded sectional view of a part. (11) …… Face plate, (11A) …… Phosphor screen, (1
2) …… skirt part, (2) …… shallow mask, (2
a) ... electron beam passage hole, (4) ... funnel part,
(5) …… Net section. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (2)

[Claims] 1. A flat plate-like color selection, which faces a face plate and an inner surface of the face plate, and is provided with a tension in a plane direction so that thermal expansion due to collision of an electron beam can be absorbed by tension relaxation. In a color cathode-ray tube having a sheer dough mask for use and a skirt portion holding the sheer dough mask and the face plate, an inner surface of the face plate is set such that a curvature radius in a diagonal axis direction on a screen> a curvature radius in a horizontal axis direction> a vertical axis. While forming the face plate and the skirt portion integrally so as to form a curved surface having the relationship of the upper radius of curvature, the gap difference between the center portion and the peripheral portion of the face plate and the shear mask is The phosphor dots on the inner surface of the face plate are absorbed and the entire area of the screen is centered. The shadow mask type color cathode-ray tube is characterized in that the pitch of the electron beam passage hole of the shear mask is made continuously smaller by going from the center to the periphery of the screen so that the pitch is almost the same as the pitch in the above. . 2. A pitch of the electron beam passage hole of the shear mask is set to a value which satisfies a condition of 80% or more in the peripheral portion with respect to the center of the screen in the pitch of the phosphor matrix on the inner surface of the face plate. Range 1st
The shadow mask type color cathode ray tube described in the item.