KR20010018041A - Tension mask of CRT - Google Patents

Abstract

PURPOSE: A tension mask for a color cathode-ray tube is provided to improve a difference in the intervals of electron beam passage holes at the boundary between an effective area and a non-effective area, thereby reducing mask cutting phenomenon due to tension and applying uniform tension. CONSTITUTION: A tension mask(5) includes an effective area(10) corresponding to a fluorescent film realizing images on a panel, a non-effective area(12) surrounding the effective area, and a connection area(11) with a predetermined width placed between the effective area and the non-effective area. The effective area has a plurality of electron beam passage holes(17). The area of the electron beam passage holes per unit mask area is gradually reduced with reaching the boundary between the effective area and the connection area.

Description

Tension mask of color cathode ray tube {Tension mask of CRT}

The present invention relates to a color cathode ray tube, and more particularly, a tension mask that performs the color discrimination function of an electron beam in a cathode ray tube has an effective surface and an invalid surface boundary region due to a stress difference for each region when a tensile force is applied from the outside. The present invention relates to a tension mask for cathode ray tubes for improving a phenomenon in which breakage occurs.

In general, color cathode ray tubes are the most widely used display devices for observation of oscilloscopes, radars, etc., including television receivers.

The color cathode ray tube includes red, green, and blue phosphor pixels having three primary color emission spectra of light, which is an all-optical device that converts image information received as an electrical signal into visual information, graphite as a light absorbing material, and A device that plays a role of reproducing a color image through a fluorescent film made of an aluminum film for improving brightness and transmitting it to human vision. When power for operation is applied, electrons are activated at a cathode of an electron gun and are emitted by an electric field. At this time, the electron beam having the kinetic energy accelerated by the acceleration electrode of several tens of kV is made to be a constant velocity motion and finally hit the fluorescent surface formed in a predetermined pattern on the inner surface of the screen to emit the phosphor to implement the image. At this time, about 75 to 80% of the accelerated electrons are blocked by the mask, which is a color-selective electrode, and only the remaining light passes through the electron beam passing holes formed on the mask surface to reach the screen to emit light.

The blocked electrons are decelerated in a short time so that almost all of the kinetic energy is converted into thermal energy, and the rest are converted into electromagnetic waves and the like to satisfy the law of energy conservation.

On the other hand, the thermal energy converted into kinetic energy thermally expands the mask made of metal, thereby causing displacement of the electron beam through hole at the position, which changes the path of the electron beam incident on the screen, thereby lowering the color purity. This property is called doming, and in order to reduce this phenomenon, recently, a tension mask of a thin film has been used.

Such tension masks counteract thermal strain due to thermal expansion by applying a mechanical strain, that is, a tensile force in advance, and a grill mask that is only stretched in the vertical direction depending on the direction in which the strain is applied, or horizontal / vertical. It is divided into a kind of flat tension mask which stretches in all directions.

On the other hand, the strain applied to the mask can be represented by the following [Equation 1].

Where ε _M and ε _T represent mechanical strain and thermal strain, σ is strain, E is Young, s modulus, α is thermal expansion coefficient, and ΔT is temperature change.

In this case, ε _M and ε _T have opposite signs. In other words, the tension direction is reversed. When ε _M = ε _T, it is the time when domming occurs. Of course, even when ε _M > ε _T , the electron beam through holes formed in the mask may be displaced on the mask surface to balance the repulsive force across the mask, but the color purity may be lower than the above mentioned amount. .

The apparatus shown in FIG. 1 is described as an example of the planar cathode ray tube to which the tension mask is applied.

The flat cathode ray tube forms a front screen and a panel 1 having a fluorescent surface 1a formed on an inner side thereof, and a rear side of the panel 1 which is coupled to a rear side of the panel 1 to form a high vacuum, and to which an internal graphite is coated on an inner surface thereof. The outer container is formed of a funnel (2).

In the neck portion of the funnel 2, an electron gun 3 emitting three electron beams of R, G, and B is enclosed, and an electron beam emitted from the electron gun can be landed on the entire screen on the front side of the electron gun 3. A deflection yoke (4) for deflecting is positioned, and a flat tension mask (5) for screening electron beams is fixed to the rail (6) inside the panel (1) in a state where tensile force is applied thereto. It is located at a constant interval with the.

On the other hand, the flat tension mask 5 is formed of a metal plate of a thin film (about 0.025mm or less) and has a structure in which a plurality of slot-shaped electron beam through holes 7 extending in a vertical direction and the like are arranged. Long edges) and both side edge portions in the horizontal direction (short side) are stretched by the rails 6 to be stretched and welded to the rails 6.

Figure 2 shows the shape of a conventional tension mask (5), the conventional flat tension mask is a vertical pitch (Pv) and horizontal pitch (Ph) and vertical bridge constant number of passing holes (7) so that the electron beam can pass through The effective surface 10 which forms the V and the horizontal bridge H, and the non-effective surface 12 in which the through-hole 7 is not formed but the end is welded and fixed to the rail 6 are formed, Although the through hole 7 is formed between the effective surface 10 and the non-effective surface 12 to minimize the stress imbalance when a tensile force is applied to the mask, a fluorescent film 1a is formed on the inner surface of the panel 1 corresponding thereto. ) Is divided into a connection surface 11 which is not formed.

In the figure, reference numeral 5a denotes a welded portion that is coupled to the rail 6.

3 shows the area distribution per unit area of the electron beam through hole 7 according to the position in the conventional tension mask, and shows the area from the center of the mask to the welded portion 5a of the mask by position.

According to the above-described conventional technique, the area of the through hole 7 per unit area of the tension mask appears the same on the effective surface 10 but decreases rapidly on the connecting surface 11 to minimize the stress imbalance. It can be seen from Figure 3 that the disappearance at (12). In other words, the vertical bridge (V) between each through hole 7 in the connecting surface 11 is rapidly increased toward the outside.

However, in the tension mask according to the prior art, the tension force F is welded to the rail 6 by pulling it outward in a direction perpendicular to each side of the mask. As a result, at the boundary between the connection surface 11 where the vertical bridges V between the respective through holes 7 become large and the effective surface 10 where the through holes 7 have the same vertical bridge V, the stress is reduced. An unbalance and a sudden change in the elastic modulus occur, so that the bridge through which the through hole 7 vertically divides the through hole of the mask between the first and third rows of the effective surface 10 is broken, so that There was a problem that the loss in production.

The present invention has been invented to solve the problems of the prior art as described above to alleviate the change of the vertical spacing of the discontinuous abrupt through hole at the boundary between the effective surface and the connection surface of the tension mask to reduce the mask rupture phenomenon due to the tensile force The purpose of the present invention is to reduce the amount of tension and thereby allow a more uniform and higher tensile force to be applied in the manufacture of the tension mask.

1 is a perspective view of a mask separation of a typical flat cathode ray tube.

2 is a front view of a tension mask according to the prior art.

3 is an electron beam through hole distribution according to mask positions according to the related art.

4 is an electron beam passage hole distribution for each mask position according to an exemplary embodiment of the present invention.

5 is a front view of a tension mask according to the embodiment.

6 is an electron beam passage hole distribution for each mask position according to another embodiment of the present invention.

*** Explanation of symbols for the main parts of the drawing ***

1: panel, 2: funnel, 3: electron gun, 4: deflection yoke, 5: tension mask

5a: welded portion, 6: rail, 10: effective surface, 11: connecting surface, 12: invalid surface

17: electron beam through hole

The present invention for achieving the above object is an effective surface of the center side corresponding to the fluorescent film to implement the image, the non-effective surface extending along the outer edge of the effective surface, located between the effective surface and the non-effective surface In the tension mask for color cathode ray tube comprising a connecting surface having a predetermined width, and having a plurality of electron beam through holes formed in at least the effective surface:

The area of the electron beam through-hole per unit area of the mask is characterized in that the area gradually decreases toward the connecting surface side from the outside of the effective surface.

On the other hand, the electron beam through hole region extends to the connection surface; The area of the electron beam through hole is preferably reduced gradually toward the boundary with the ineffective surface.

On the other hand, it is preferable that the effective surface width at which the electron beam through hole area per mask unit area is reduced is similar to the width of the connection surface.

In this way, it can be seen that the change in the vertical spacing of the discontinuous abrupt through-holes at the boundary between the mask effective surface and the connecting surface is reduced, so that more uniform and more tensile force can be applied.

As a result, there is an advantage that the fracture phenomenon at the time of mask tension can be prevented.

And, there may be a plurality of embodiments of the present invention, hereinafter will be described in detail with respect to the most preferred embodiment.

Hereinafter, exemplary embodiments of the tension mask according to the present invention will be described in detail with reference to the accompanying drawings.

In addition, in drawing used for description, about the component similar to the prior art, the same code | symbol is attached | subjected, and the overlapping description may be abbreviate | omitted.

4 is a view showing the distribution of electron beam through hole area for each mask position according to an embodiment of the present invention, Figure 5 is a view showing the through hole formation state of the tension mask according to the embodiment, Figure 6 is another embodiment Figure showing the electron beam through hole area distribution according to the mask position according to.

The tension mask 5 according to the exemplary embodiment includes an ineffective surface 12 including an effective surface 10, a connection surface 11, and a rail welding portion 5a, and includes an electron beam through hole 17 per unit area. As shown in FIG. 4, the area is constant at the center of the effective surface 10, and gradually decreases from about 5 mm from the boundary with the connecting surface 11 to the ineffective surface (the end of the connecting surface 11). It disappears at the boundary with 12).

That is, to change the area of the through hole 17 is to inversely change the vertical bridge (V) between the through holes, as shown in Figure 5 the horizontal bridge (H) between the through holes If it is made constant and the vertical bridge V between the passing holes is gradually increased from the outside of the effective surface 10 to the connecting surface 11, the through holes 17 are not formed when the mask is tensioned. The elastic modulus or stress of the ineffective surface 12 can be evenly transmitted to the effective surface 10.

In general, when the area of the passage hole 17 per unit area becomes small, the amount of electron beam passing through the passage hole becomes proportionally smaller, so that the phosphor formed on the inner side of the panel cannot be sufficiently emitted, which lowers the luminance at the corresponding area. Can be imported. Therefore, since the area that does not matter even if the area of the through hole 17 per unit area becomes small is 5 mm from the end of the effective screen, the area of the through hole gradually decreases from about 5 mm from the end of the effective surface 10. It is preferable to form.

In addition, the spacing of the connecting surface 11 is about 5 mm, so that the formation of the through hole at the end of the effective surface 10 is similar to the extent of decreasing the area of the through hole. To make it happen or to change.

However, moiré, which is an interference fringe generated by the vertical gap between the scanning line of the electron beam and the mask, is to be changed in changing the vertical bridge V.

And as another embodiment for changing the area of the through hole 17 per unit area as described above, while maintaining the vertical bridge (V) of the through hole equal to the size of the horizontal bridge (H) gradually toward the outside There may be a method of increasing or increasing the vertical bridge (V) at the same time, in addition to the horizontal pitch (Ph) is gradually reduced and the horizontal bridge (H) of the through hole 17 is the same, or the horizontal pitch (Ph) Increasing the horizontal bridge (H) while maintaining the same) can have the same effect, it is possible to form a combination of these enumerations.

In addition, in another embodiment of the present invention, as shown in the area distribution diagram shown in FIG. 6, the effective surface 10 in a state in which the electron beam passage hole 17 is not formed in the ineffective surface 12 and the connecting surface 11. It is formed so as to reduce the area of the through hole per unit area outside the), it is possible to reduce the discontinuous and sudden stress change at the boundary between the ineffective surface 12 and the effective surface (10).

On the other hand, while a specific embodiment of the present invention for the change in the area of the through hole per unit area has been described and illustrated above, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments should fall within the appended claims of the present invention.

As described above, the present invention gradually decreases the area of the through hole per unit area in the mask effective surface from the outside, thereby improving the change in the spacing of the abruptly abrupt electron beam through hole at the boundary between the connecting surface and the effective surface, thereby There is an advantage that can prevent the breakage phenomenon.

This also allows more uniform and more tensile force to be applied on the tension mask.

Claims (3)

An effective surface of the center side corresponding to the fluorescent film that implements an image on the panel, an invalid surface extending along the outer edge of the effective surface, and a connection surface having a predetermined width positioned between the effective surface and the invalid surface; In the tension mask for color cathode ray tube, in which a plurality of electron beam passing holes are formed at least in the effective surface: The area of the electron beam through-hole per mask unit area, the area of the color cathode ray tube tension mask, characterized in that the area gradually decreases toward the boundary with the connection surface from the outside of the effective surface. The method of claim 1, The electron beam through hole region extends to the connection surface; The area of the electron beam through hole per unit area of the mask is gradually reduced toward the border with the ineffective surface, the tension mask for color cathode ray tube. The method of claim 1, The effective surface width of the electron beam through-hole area per unit area of the mask is reduced is similar to the width of the connecting surface, the tension mask for color cathode ray tube.