JPH05135706A - Color cathode-ray tube and manufacture of fluorescent screen thereof - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a color mixture and a drift by the environmental magnetic field such as geomagnetic field by forming holes of the black matrix film of a dot type fluorescent screen into an elliptic shape having the long axis in the specific direction. CONSTITUTION:Holes 5 of a black matrix film on a glass panel 1 are formed into an elliptic shape having the long axis perpendicular to the shift direction of the landing spot 4 of an electron beam. The opening area of the hole 5 is made equivalent to a conventional circular hole, thus the interval between peripheries of the adjacent elliptic holes in the short axis direction is made longer than that of the circular holes. When the spot 4 is moved by the effect of the environmental magnetic field to collide with the dot of an adjacent different-color phosphor and illuminate it in addition to the dot of a phosphor to be primarily illuminated, its luminescence portion is covered by the black matrix film and invisible to an image observer.

Description

Detailed Description of the Invention

[0001]

[Industrial application] A high-definition color cathode ray tube using a dot-type fluorescent surface, even if the electron beam's fluorescent surface reaching point (beam landing spot) changes due to the influence of the environmental magnetic field such as the earth's magnetic field. The present invention relates to a color cathode ray tube in which color mixing, color misregistration, etc. do not occur and a method for manufacturing a fluorescent surface thereof.

[0002]

2. Description of the Related Art A display terminal (VD) of an information processing system
For high-definition color cathode ray tubes for T), all three electron guns are arranged in a so-called in-line on a horizontal plane passing through the tube axis (the main arrangement of the electron gun array of the current shadow mask type color cathode ray tube is However, a color cathode ray tube in which a dot-shaped shadow mask having a circular hole, and thus a dot-type fluorescent surface is combined, has been often used. Since the color cathode ray tube for the above-mentioned applications is not bound by international standards and the like like the television broadcast picture tube, it is required to increase the number of horizontal scanning lines arbitrarily for each system to improve the definition. There were things. On the cathode ray tube manufacturer side, in order to efficiently deal with such high-mix low-volume products, various efforts have been made.
According to Japanese Patent Laid-Open No. 45343/1993, the vertical arrangement of the holes for passing the shadow mask electron beam is set independently of the horizontal arrangement, and the shape of the holes is defined by a beam trio whose major axis is the electron beam emitted from the three electron guns. After passing through the same hole in the shadow mask, it reaches three points adjacent to each other on the fluorescent surface, which is called a beam trio). There is disclosed a technique of forming an oval shape which decreases in response to a lateral deviation from. By doing so, the existing shadow mask shaping type or the like is diverted, and in a short time, due to the color cathode ray tube for VDT of the system in which the number of horizontal scanning lines different from the conventional one is used, moire beat does not occur, and it is optimal over the entire surface. , It becomes possible to easily design and develop a shadow mask that can realize the closest beam utilization rate. Although this technology is very convenient for manufacturers, it does not consider the effects of the environment of use.

[0003]

There is a so-called environmental magnetic field on the earth due to the earth's magnetic field and electric equipment in the vicinity where current flows, and the electron beam in the color cathode ray tube also exerts its influence (in the electron movement direction and the magnetic field direction). The flight trajectory is bent by the force of the Lorentz orthogonally. In order to suppress the influence of the environmental magnetic field as much as possible, an inner shield is currently provided along the inner surface of the funnel to surround the space where the electron beam in the color cathode ray tube flies and to prevent the environmental magnetic field from entering. Generally, the effect of the inner shield is not sufficient for the magnetic field component in the direction. The Lorentz force due to the tube axis direction component of the environmental magnetic field acts in the direction of the arrow in FIG. 2A, which is a front view of the display screen viewed from the image observer side, and the action causes the fluorescent surface of the electron beam. The arrival point 4 is shown in FIG.
It shifts as shown in FIG. However, FIG. 2B is an enlarged view of the portion A in FIG. 2A. In these drawings, 1 is a panel, 2 is an arrow indicating the movement of the electron beam fluorescent surface reaching point, and 3 is described later. Conventional round holes 4 in the black matrix film are electron beam landing spots (points that reach the fluorescent surface).
It can be seen that when the deviation is large, the adjacent different color phosphor dots are also projected to emit light, and the light emitting portion is likely to be seen through the holes 3 of the black matrix film. If the deviation of the landing spot 4 of the electron beam becomes larger than this, the electron beam also strikes and emits light to the fluorescent dot of another color adjacent to the fluorescent dot that is supposed to emit and emit light. The different color light emitting portion becomes visible through the hole 3 of the black matrix film, causing problems of color mixing and color misregistration.

As is well known, a specific hole is formed in a shadow mask of a color cathode ray tube using a dot type fluorescent surface, and a fluorescent film is formed on the back surface of a panel which is to be illuminated by an electron beam passing through the hole. Since the relative position of the light surface with respect to the phosphor dots for a specific primary color must be maintained extremely accurately, currently, a specific shadow mask is attached and combined to a specific panel in the same manner as when using it, and photolithography technology is used to combine them. It forms the light surface. In the current color cathode ray tube, a black matrix film for preventing the reflection of irradiation light from the outside and improving the contrast fills the spaces between the dots of each primary color phosphor. That is, in practice, it is the hole position and shape of the black matrix film that determine the dot position and shape of each primary color phosphor viewed from the image observer. Even if the fluorescent dots are projected by the electron beam and emit light, if they are covered with the black matrix film, they cannot be seen by the image observer. Therefore, in order to suppress the influence of the environmental magnetic field, the hole position and shape of the black matrix film must first be appropriately determined. The black matrix film is formed prior to the application of the photosensitive fluorescent film, and is usually much thinner than the fluorescent film, and the positions and shapes of the holes are accurately determined and formed by exposure.

Conventionally, as an exposure light source for exposing the photoresist film in the step of forming the black matrix film to determine the hole shape and position of the black matrix film, the arc light emitting portion of the long arc ultra high pressure mercury lamp is orthogonal to the arc. A black matrix film is formed into a perfect circle by covering it with a pipe-shaped light-shielding plate with a slit and rotating it around an orthogonal axis passing through the center of the slit to form a point light source. Had formed holes. However, even if a fluorescent surface having a perfect circular hole formed in the black matrix film is used, there is no effect in suppressing color mixing and color shift due to the influence of the environmental magnetic field.

The present invention solves the above-mentioned problems and provides a color cathode ray tube using a dot type fluorescent surface and a method for manufacturing the fluorescent surface, which can prevent color mixing and color shift due to an environmental magnetic field. The purpose is to do.

[0007]

In order to achieve the above object, in the present invention, a shadow mask having a circular opening for passing an electron beam and a black matrix film for improving the contrast are filled between the phosphor dots. In a color cathode ray tube having a dot type fluorescent surface, the electrons of the electron beam scanning the fluorescent surface are caused by the deflection motion toward the panel periphery and the axial component of the environmental magnetic field. With respect to the direction of the Lorentz force acting at a right angle to, the hole shape of the black matrix film is set to an elliptical shape having a major axis in the direction orthogonal to the Lorentz force. However, the opening area of the oval holes of the black matrix film according to the present invention is set to be equivalent to that of the conventional black matrix film having true circular holes.

As a method of manufacturing the fluorescent surface of the color cathode ray tube of the present invention in which the electron beam passage opening is formed in the elliptical shape in the peripheral portion of the black matrix film, the black matrix film on the fluorescent surface is subjected to a photolithography technique. As an exposure light source for forming by, the arc direction of the long arc ultra-high pressure mercury lamp is arranged parallel to the XX axis of the panel,
A tubular light-shielding plate having a slit orthogonal to the arc and covering the arc light emitting portion was used, and this light source was oscillated in the tube axis direction and the Y-Y axis direction of the panel during exposure.

[0009]

The function of the present invention is simply described. The non-aperture area of the black matrix film is increased with respect to the changing direction of the arrival point of the fluorescent surface of the electron beam due to the environmental magnetic field. The variation of the fluorescent beam reaching point of the electron beam due to the tube axis direction component of the environmental magnetic field is in the Y axis direction at both ends of the panel in the XX axis direction, as shown in FIG. Both ends of the panel in the Y-Y axis direction are in the X-axis direction. However, since the direction and strength of the tube axial component of the environmental magnetic field vary variously when the color cathode ray tube is used, the X-axis direction and the Y-axis direction are ± X and ± Y directions. There are both, and the degree of deviation is also variable. In the present invention, the fluorescent surface arrival point of the electron beam is shifted in the direction as described above, and even if the shifted electron beam impinges on the adjacent different color phosphor dots to emit light, the different color emission The part is covered by the black matrix film so that it cannot be seen by the image observer. In the direction in which the electron beam is displaced (the part covered by the film from the peripheral edge to the peripheral edge of the adjacent black matrix film for different color phosphors). The width of the holes in the black matrix film is narrowed so that the area of the light emitting area becomes narrower and the image display becomes darker. The width of the holes in the black matrix film is widened so that the area of the fluorescent dot emitting portion that can be seen from the outer surface of the panel through the holes in the black matrix film, that is, the area of the openings in the black matrix film is Set to be equivalent to the case of the circle.

When the exposure light source is oscillated reciprocally in the tube axis direction with the exposure light source stopped at the midpoint of the oscillation in the Y-Y direction, the shape of the exposed portion in the peripheral portion of the panel to be exposed has a long axis direction. It becomes an oval shape that faces the center of the panel. If the exposure light source is reciprocally rocked in the Y-Y axis direction while being stopped at the midpoint of the rocking in the tube axis direction, the exposed portion of the exposed panel rocks in the ± Y directions. The effect of enlarging the exposed portion due to the rocking is relatively large in the peripheral portion of the panel and small in the central portion. The actual swing amount is shorter than the width of the slit of the light shielding plate that covers the light source arc.

With the above arrangement, due to the influence of the tube axial direction component of the environmental magnetic field, the electron beam also strikes the different color phosphor dot adjacent to the phosphor dot which is supposed to emit light and partially emits light. At that time, the possibility that the different color light emitting portion is visible from the outside through the holes of the black matrix film is significantly reduced, the tolerance against color mixing and color misregistration is improved, and the white spot uniformity is improved.

[0012]

1 (a) is a front view of a black matrix film in the peripheral portion of the fluorescent surface of a color cathode ray tube of an embodiment of the present invention, and an enlarged view of a portion B at the end of the XX axis is shown in FIG. 1 (b). ). As well understood by comparing FIG. 1A and FIG. 2A, which shows the direction in which the landing spot 4 of the electron beam moves due to the environmental magnetic field, the black matrix film of the color cathode ray tube according to the present invention can be seen. The hole 5 has an oval shape whose major axis is orthogonal to the moving direction of the landing spot of the electron beam. Since the opening area of the oval holes is equivalent to the true circular holes of the conventional black matrix film as described above, the black matrix between the peripheral edges of the adjacent oval holes of the black matrix film. The distance in the minor axis direction covered by the film is longer than the distance between the peripheral edges of the conventional perfect circular holes. Therefore, even if the landing spot of the electron beam moves due to the influence of the environmental magnetic field and hits the dots of the fluorescent substance that should be emitted originally, and also the dots of the adjacent fluorescent substance of different colors, the adjacent spots are also emitted. The light emitting portion of the different color fluorescent material dot is covered with the black matrix film and cannot be seen by the image observer. That is, the tolerance of shooting in other colors is improved.

As for the hole shape of the black matrix film having the oval shape, when the ratio of the long diameter to the short diameter exceeds about 1.15, the distance between the adjacent holes of the black matrix film in the long axis direction. Is too short, and the electron beam landing margin (beam lack, tolerance for other colors) in this direction becomes small, which is not preferable. In order not to deteriorate the image quality in the high definition color cathode ray tube for VDT,
The above-mentioned major / minor diameter ratio of about 1.15 is almost the limit, and it is desirable to keep the ratio below this value. To give an example of specific numerical values, a perfect circular hole having a diameter of 100 μm is formed in a horizontal direction pitch of 162 μ in the black matrix film at the center of the fluorescent surface.
m, the vertical pitch is 280 μm, and when the shortest distance between adjacent true circular holes is 62 μm (the distance between them is covered with a black matrix film), the length / shortness of the four corners of the screen The longest dimension of the hole with the maximum diameter ratio is 10
5 μm, the short diameter dimension is 95 μm, and the long / short diameter ratio is about 1.11.

Next, an example of a specific method for forming the black matrix film according to the present invention by the photolithography technique will be described. The black matrix film is formed by first forming a photoresist film on the back surface of the glass panel, and exposing the photoresist film with light that has passed through the electron beam passage opening of the shadow mask. However, the exposure operation is repeated three times by changing the light source position in correspondence with the in-line arranged three electron gun. After that, only the portion solidified by exposure is left and the unexposed portion is removed by a developing operation. A black matrix film liquid made of pure graphite is applied over the entire surface, dried once, and then the photoresist film is peeled off from the panel glass surface by an etching solution, and is adhered on it together with the photoresist film by a so-called lift-off method. The black matrix film in the affected area is lifted and partially removed. As a result, only the black matrix film in the portion in direct contact with the panel glass surface remains. Since the black matrix film is formed as described above, the shape of the oblong holes of the black matrix film according to the present invention is determined during the exposure operation. The light source used for this exposure work is, for example, as shown in FIG. 3, a long arc ultra high pressure mercury lamp covered with a tubular light shielding plate having a slit orthogonal to the arc axis, and the arc axis direction is taken along the line XX of the panel.
The one arranged parallel to the axial direction is used without being rotated.
In FIG. 3, 1 is a panel to be exposed, 6 is an ultra-high pressure mercury lamp, and 7
Is an arc light emitting portion, and 8 is a tubular light shielding plate. Further, FIG. 4 is a view for explaining the direction in which the ultra-high pressure mercury lamp is swung, in which the mercury lamp for a light source is reciprocally rocked in the YY direction and the tube axis direction, that is, the ZZ direction reciprocated in FIG. It is shown that the movement 10 is performed. When the Y-axis swing 9 is performed, the light source is fixed at the midpoint position of the Z-axis swing 10. Conversely, when the Z-axis swing 10 is performed, the light source is swung in the Y-axis direction. It is performed with the center fixed at 9. Either the Y-axis direction swing 9 or the Z-axis direction swing 10 may be prioritized. Further, the same effect can be obtained even if the reciprocal swing exposure method is changed to the stepwise movement exposure method. When using a long arc ultra high pressure mercury lamp as a light source by covering it with a tubular shading plate with slits, there is a problem that only a small part of the total light emission is used, but since it is AC lighting, the power supply is simple and the light emission center position changes. Is excellent in that it does not require a light source position correction means corresponding thereto, and has a relatively long life, and in the case of the light source according to the present invention, since it is not rotated, it is easy to supply cooling water.

[0015]

As described above, according to the present invention, the fluorescent beam reaching point of the electron beam varies due to the influence of the tube axial direction component of the environmental magnetic field, and even if the electron beam is supposed to emit fluorescence. In addition to the body dots, even if the adjacent different color phosphor dots that should not be made to emit light are also made to emit light,
The light emitting portion of the different color phosphor dots is covered with the black matrix film and is not visible to the image observer. That is, the color cathode ray tube according to the present invention has an improved electron beam landing margin (immunity margin for other colors).

[Brief description of drawings]

1 (a) is a front view of a black matrix film around a fluorescent surface of a color cathode ray tube according to an embodiment of the present invention, FIG.
FIG. 1B is an enlarged view of an XX axis end B portion in FIG.

2 (a) is a front view of a display screen in which a direction in which a fluorescent plane arrival point (beam landing spot) of an electron beam changes due to an influence of an environmental magnetic field is indicated by an arrow, and FIG. 2 (b) is FIG. It is an enlarged view of the A section in (a).

FIG. 3 is a diagram showing a light source obtained by covering a long arc ultra-high pressure mercury lamp used for an exposure operation with a tubular light shielding plate with a slit in the present invention, and a position with respect to an exposure target panel.

FIG. 4 is a diagram illustrating a direction in which an ultra-high pressure mercury lamp as a light source is swung in the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Panel, 2 ... Arrow which shows movement of an electron beam fluorescent surface reaching point, 3 ... True circular hole of a conventional black matrix film, 4 ... Landing spot of an electron beam, 5 ... Hole of the black matrix film according to the present invention , 6 ... Ultra-high pressure mercury lamp, 7 ... Arc light emitting part, 8 ... Tubular shading plate, 9 ...
Reciprocating rocking in the Y-Y direction, 10 ... Reciprocating rocking in the tube axis direction, that is, the Z axis direction.

Claims (2)

[Claims] 1. A color cathode ray tube having a shadow mask having an opening for passing an electron beam and a dot type fluorescent surface in which spaces between fluorescent dots are filled with a black matrix film. With respect to the direction of the force acting on the electrons of the beam at a right angle due to the deflection motion toward the peripheral portion of the panel and the axial component of the environmental magnetic field, the hole shape of the black matrix film is changed to the above-mentioned force. A color cathode ray tube having an elliptical shape having a long axis in a direction orthogonal to. 2. A method for producing a fluorescent surface of a color cathode ray tube, comprising: a shadow mask having an opening for passing an electron beam; and a dot-type fluorescent surface in which spaces between fluorescent dots are filled with a black matrix film. As an exposure light source for forming a matrix film by photolithography technology,
Long arc The direction of the arc of the ultra-high pressure mercury lamp is indicated by X on the panel.
-This is arranged parallel to the X-axis, and the arc light-emitting part is covered with a tubular light-shielding plate having a slit orthogonal to the light-emitting part. This light source is reciprocated in the tube axis direction and the Y-Y axis direction of the panel during exposure. A method for manufacturing a fluorescent surface of a color cathode ray tube, which is characterized in that it is rocked.