JPH083978B2 - 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. 6 is a schematic view 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) to heat and heat the sheer dough mask (2) to thermally expand the sheer dough mask (2). Therefore, by setting the tension and the thermal expansion amount at substantially the same level, the thermal expansion is absorbed by the tension relaxation to suppress the deformation of the shadow mask (2), and the landing error of the electron beam is greatly reduced. It is possible to reduce the number and obtain a screen that is easy to see.

[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 manufactured, the face plate (11) generally made of glass and the skirt part (12) need to be individually processed, resulting in poor productivity. ) And the skirt (12) are welded together, the yield,
We could not avoid problems such as 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 the Problems] In the shear mask type color CRT according to the present invention, the face plate and the skirt are integrally formed by forming the face plate inner surface into a spherical shape, and the center of the face plate is formed. The difference in the gap between the shadow mask and the peripheral portion of the shadow mask is absorbed, and the pitch of the phosphor dots provided on the inner surface of the face plate is almost the same as the pitch in the central portion across the entire screen. It is characterized in that the pitch of the beam passage hole is made continuously smaller as it goes from the central part of the screen to the peripheral part.

[Operation] According to the present invention, by making the inner surface of the face plate a spherical surface, it is possible to easily and accurately perform integral molding by pressing including the skirt portion without causing a swirl phenomenon. Also, the fluorescent surface inside the face plate becomes a spherical surface, and the facing interval with the flat plate-shaped shead mask differs between the central part and the peripheral part, but the pitch of the electron beam passage hole of the shedow mask is changed according to this interval difference. As a result, the interval between the phosphor dots and the screen pitch proportional thereto can be set in a range that does not become unnatural in practical use, and the screen can be easily viewed.

[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,
Detailed explanations thereof are omitted.

In the shear mask type color CRT, the face panel (13) is formed by integrally molding the face plate (11) and the skirt portion (12) with a press. The inner surface of the face plate (11) of the integrated face panel (13) is formed into a spherical surface, as clearly shown in FIG. 2, and the fluorescent surface (11A) is adhered to the 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 it goes from the central part to the peripheral part of 1), the relative size of the inner surface of the face plate (11) to the fluorescent screen (11A) is gradually reduced so as to satisfy a predetermined condition. Hereinafter, a configuration for satisfying the above predetermined condition will be described in detail.

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

An example of a normal dot type fluorescent screen and an in-line beam type CRT will be described. The relationship between the fluorescent screen dot (21) and the screen pitch is as shown in FIG. It is necessary to arrange the R, G, and B phosphor screen dots (21) so that they are correctly aligned, and the interval between the R, G, and B phosphor screen dots (l). Should be one-third of the horizontal triopitches (PH).
Therefore, it is inevitable if the screen pitch (PS) of the cathode ray tube, the interval (S) between the R, G, and B beams of the electron beam (30) emitted from the electron gun, the size of the cathode ray tube, and the deflection angle are determined. Then, the dimension (L) from the deflection center of the electron beam to the shear mask (2), and the dimension (Q) from the shear mask (2) and the fluorescent surface (11A) inside the face plate (11) are determined. At this time, the interval (d0) between the R, G, and B phosphor screen dots (21) at the center of the screen is However, this is the shadow mask (2) and the fluorescent screen (11
When both A) and are flat plates, and the shadow mask (2) is a perfect plane and the face plate (11) inner surface is spherical, the value of (d) is set according to the peripheral portion. If is not made smaller, which 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.

The conditions in Fig. 5 are: L = 184.5mm Q = 6.5mm S = 5.1mm Screen size: Diagonal = 175mm Horizontal = 130mm Vertical = 100mm Radius of curvature of face plate (R) = 10,000mm 15,000mm 20,000mm As is clear from Fig. 5, in this combination, the value of (d) in the case of R 10,000mm on the face plate inner surface is 25% smaller than the center at the worst point at the diagonal end of the screen, Since this (d) is proportional to the screen pitch (PS), the screen pitch is also 25% with respect to the center.
It is necessary to make it small, and R on the inner surface of the face plate
Is 15% when R is 15,000 mm, and 10% when R is 20,000 mm. The lower limit is 10,000 mm R, and a spherical surface of 15,000 mm R or more is desired.

On the other hand, as a problem at the time of press molding of glass, when the inner surface 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. The upper limit is about 20,000 mm R.

From the examination result of the above example, it is desirable to set the radius R of the inner surface of the face plate in the case of a 15-inch CRT to be about 15,000 to 20,000 mm.

That is, the distance (d) between adjacent phosphor dots is the center / peripheral ratio. It is necessary to define the variation amount of R on the inner surface of the face plate and the hole pitch of the shadow mask so that the combination satisfies the condition (1).

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

As is clear from the above equation (2), since the phosphor dot interval (d) and the screen pitch (PS) are in a proportional relationship, the dot interval (d) used in the above description is used.
The ratio between the center and the periphery of the screen pitch (PS)
It 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

[Effects of the Invention] As described above, according to the present invention, by making the inner surface of the face plate a spherical surface, the face panel including the face plate and the skirt portion can be pressed into a press without causing a swirl phenomenon. It is possible to integrally mold by this, thereby improving 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 interval 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 spherical surface of the face plate and the flat-plate shed mask, It is possible to obtain a bright and easy-to-see screen by making corrections by adjusting the electron beam passage hole pits and making simple improvements in the fabrication 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, 0.31mm screen-pitch CRT, and Fig. 6 is a partially cut-away front view of a conventional shadow mask type color CRT. , Fig. 7 is an enlarged cross-sectional view of the main part of Fig. 6 (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, the face plate and the skirt portion are integrally formed by forming the inner surface of the face plate into a spherical shape. Along with absorbing the gap difference between the center portion and the peripheral portion of the face plate and the shear 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 central portion across the entire screen. Pitch of the electron beam passage hole of the above-mentioned shear mask so that it becomes a pitch. A shadow mask type color cathode-ray tube characterized in that it is made smaller continuously from the center of the screen toward the periphery. 2. The pitch of the electron beam passage hole of the shear mask is set to a value which satisfies the condition of 80% or more in the peripheral portion with respect to the screen center in the pitch of the phosphor matrix on the inner surface of the face plate. The shadow mask type color cathode ray tube according to the first item of the range.