JPH11224613A - Shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent deformation of a mask by impact efficiently without complicating a structure by suspending deformation preventing wire along the back face of the mask between opposite sides of a frame body with an interval the mask. SOLUTION: A deformation preventing wire 40 made of a copper wire or the like is arranged along the back face of a mask 30, and both ends of the deformation preventing wire 40 are inserted into wire holes 32 formed through the suspension edges 33 of the mask 30 and are fixed to a frame body 20 on the outside. The deformation preventing wire 40 is suspended to connect just center positions of opposite sides in the longitudinal direction of the frame body 20. When an impact is applied in the direction perpendicular to the face of a shadow mask 10, the mask 30 gradually curved upward is deformed in the downward curving direction opposite to the non-curving direction into contact with the deformation preventing wire 40. The deformation preventing wire 40 intends to keep its attitude, thus the excessive deformation of the mask 30 by the impact can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask which is incorporated in a cathode ray tube of a color TV or the like and controls passage of a cathode ray.

[0002]

2. Description of the Related Art A shadow mask is provided with a cathode ray passing portion composed of a number of fine holes and slits, and a cathode ray emitted from an electron gun of a cathode ray tube passes through the cathode ray passing portion of the shadow mask and has a front surface. By causing the phosphors of the panel to emit light, a screen is formed as a set of fine light spots.

The general structure of a shadow mask is as follows.
It comprises a rectangular frame made of a steel material or the like, and a mask made of a stainless thin film or the like and formed with a hole or a slit serving as a cathode ray passage portion therethrough. By attaching a thin mask to a highly rigid frame, the positions of the mask and the cathode ray passage portion are accurately maintained. However, when the shadow mask is transported at the production site until it is incorporated into the TV receiver after manufacture, or when the TV receiver with the shadow mask is handled in the sales and distribution process, the shadow mask is moved in a direction orthogonal to the surface of the shadow mask. When a strong impact force is applied, there is a problem that the thin mask is deformed, the position and the shape of the cathode ray passage portion are shifted, and the quality of an image is deteriorated during use.

If the impact force is such that it can be absorbed by the elastic deformation of the mask, the mask deformed by the impact force will be immediately restored to its original shape, so that there is no problem. When a force is applied, the mask undergoes permanent deformation and cannot return to its original shape. Various techniques for preventing the deformation of the mask due to the impact force as described above have been proposed.
For example, there is a technique of increasing the rigidity of the entire mask by forming a reinforcing shape by unevenness such as ribs or steps on the mask, or changing the shape of a cathode ray passage portion formed through the mask. There is a technique for preventing deformation of the mask by increasing the rigidity of the frame and firmly fixing the entire surface of the mask to the frame in a tensioned state.

[0005]

Among the conventional techniques for preventing deformation of a mask, the technique of forming a reinforcing shape by unevenness on a mask is problematic in that it is difficult to form unevenness on a thin mask with an accurate shape. There is. In terms of the function of the mask, the shape and position of the cathode ray passage portion must be accurately set. However, when the mask is formed with irregularities, the shape and position of the cathode ray passage portion are easily shifted. It is difficult to accurately penetrate a fine cathode ray passage portion on a mask having irregularities, and if the mask on which the cathode ray passage portion is formed is subjected to irregularities, the cathode ray passage portion is easily deformed.

In order to increase the rigidity of the frame, it is necessary to use a highly rigid material for the frame or make the frame thicker or thicker, so that the weight of the frame, that is, the weight of the entire shadow mask increases. Frame manufacturing costs are also high. It is difficult to fix the entire surface of the mask to the frame in an evenly tensioned state. Also, during the manufacturing process, the variation in the tensioned state due to the location of the mask increases, and the position and shape of the cathode ray passage portion are likely to be shifted. .

In particular, in recent years, TV screens have become larger and larger.
The number of TV receivers having a large screen exceeding 28 inches has increased. In addition, there is a demand for flat screens, and the demand for flatter and larger-screen TV receivers is increasing. Therefore, a shadow mask having a large area and as close to a plane as possible is required. As the area of the mask increases and becomes closer to a plane, the aforementioned deformation problem becomes more serious. In addition, it is difficult to manufacture a large-area and nearly flat mask, and the weight of the frame is increased. Therefore, the above-described problems of the conventional deformation prevention technology become more noticeable.

As described above, when the demand for a large screen and flattening is increased, there is a limit to how the conventional deformation prevention technology can cope. It is an object of the present invention to efficiently prevent deformation of a mask due to the above-mentioned impact force without complicating the structure.

[0009]

The shadow mask of the present invention is a shadow mask which is attached to a cathode ray tube and through which a cathode ray passes, and has a frame attached to the cathode ray tube, and a cathode ray passing portion attached to the frame. A mask. The basic structure of the shadow mask is the same as that of a shadow mask attached to an ordinary cathode ray tube.

The frame is made of a highly rigid metal material such as stainless steel. However, it is not necessary to use a material having a particularly high rigidity as compared with a normal shadow mask. The shape of the frame has a predetermined shape such as a rectangular shape in accordance with the size and shape of a cathode ray tube such as a TV receiver. The mask is made of a stainless steel thin plate or the like, and a cathode ray passage portion formed of fine holes and slits is formed through almost the entire surface.

The shadow mask is provided with an over-deformation preventing means for preventing an excessive deformation when an impact force is applied to the mask. [Over-Deformation Prevention Line] The over-deformation prevention line is stretched along the back surface of the mask with a space between the mask and the opposite side of the frame.

When an impact force is applied to the shadow mask and the mask is deformed in a direction orthogonal to the surface, the over-deformation prevention line abuts on the back surface of the mask to absorb the impact energy and excessively deform the mask. Is prevented. The over-deformation prevention wire needs to have a material and a wire diameter having strength or deformation resistance enough to absorb the above-described impact energy. In addition, the over-deformation prevention lines need to be arranged at positions and dimensions that do not obstruct the passage of the cathode rays.

Specifically, a metal wire made of stainless steel, tungsten steel or the like is used as the over-deformation prevention wire. The wire diameter is preferably about 0.01 to 0.5 mm.
If the over-deformation prevention line is stretched in tension between the opposite sides of the frame, the ability to absorb impact energy will increase,
The deformation of the mask can be effectively prevented. The over-deformation prevention line can be arranged so that the mask does not touch the mask when the mask undergoes small deformation or vibration within the elastic deformation range.

The location of the over-deformation prevention line is preferably a place where the deformation of the mask can be efficiently prevented. For example, the over-deformation prevention line is placed so as to come into contact with the mask at the center position where the deformation of the mask is the largest. It is preferable to keep it. Specifically, an over-deformation prevention line can be stretched between the center of the frame side of the frame. The over-deformation prevention line may extend in a direction orthogonal to the frame side of the frame, or may extend in an inclined direction. A plurality of over-deformation prevention lines may be arranged in parallel at intervals. A plurality of over-deformation prevention lines may be arranged so as to intersect. An over-deformation prevention line may be stretched over both the short side and the long side of the rectangular frame.

[Partial fixing means] As an over-deformation preventing means,
Partial fixing means for fixing a pair of positions facing each other on the side of the mask to the outer frame body can be provided. The partial fixing means is made of various kinds of metal materials similar to those used for each structural member of the shadow mask, and has a structure capable of mechanically connecting a part of the mask and a part of the frame. Just do it.

As the partial fixing means, a plate-like partial fixing piece for connecting the connecting piece and the frame by connecting a part of the outer peripheral edge of the mask to the outside to form a connecting piece can be used.
For fixing the connecting piece and the partial fixing piece, and the partial fixing piece and the frame,
Means such as welding are applied. By arranging the partial fixing means at a pair of positions facing each other at the center of the side of the side of the mask, it is possible to efficiently prevent excessive deformation at the center of the mask where deformation is most likely to occur.

By arranging the partial fixing means at a plurality of positions on the side of the mask, over-deformation at each position can be efficiently prevented. When the mask has a curved surface due to its functional necessity, it is preferable to provide the partial fixing means at a position where the curved shape is not impaired. For example, in the case of a mask curved in a cylindrical shape, a partial fixing means may be provided at a position facing the axial direction of the cylinder.

The partial fixing means can be fixed to the frame while the pair of positions is pulled outward. Further, even when the mask is not in a pulled state at the time of attachment, it may be attached in a state where a tensile force is generated between the pair of positions and the frame when an external force is applied to the mask in a direction perpendicular to the surface. Good. As for the tensile force applied to the mask by the partial fixing means, the deformation of the mask decreases as the tensile force increases. When the partial fixing means is arranged at a plurality of locations on the mask, the magnitude of the tensile force can be adjusted in accordance with the deformation behavior of the mask at those locations.

In the portion of the mask where the partial fixing means is not attached, the side of the mask may be freely movable. Further, it may be fixed so as not to be displaced with respect to the frame material. [Deformation characteristics of the frame] As a means for preventing over-deformation, the frame has a deformation characteristic such that when a shock is applied in a direction perpendicular to the surface of the shadow mask, the mounting portion of the mask expands outward. It can be.

Deformation characteristics when an impact force is applied to the frame are determined by factors such as the cross-sectional shape such as the position of the center of gravity of the frame or the center of the inertial mass, the mounting position of the mask on the frame, and the support structure of the frame. It is determined by combining factors such as the mounting position with respect to. In general, when a portion having a large mass exists in the outer peripheral portion of the frame, the frame is deformed so as to expand outward.

The above deformation characteristics can be analyzed by numerical calculation from the shape of the frame. By repeating the analysis of the deformation characteristics and the change in the design of the frame, it is possible to design the structure of the frame having the desired deformation characteristics. When the frame has the above-described deformation characteristics, when an impact force is applied in a direction perpendicular to the surface of the shadow mask, the mask is pulled outward along with the deformation of the frame. The force that pulls the mask outward acts in a direction that prevents deformation of the mask in a direction perpendicular to the surface, so that deformation of the mask in a direction perpendicular to the surface is prevented. If the frame is designed so that the deformation becomes larger as the impact force increases, the force for preventing the deformation of the mask appropriately increases or decreases in accordance with the magnitude of the impact force.

If the deformation characteristics are merely adjusted by the structural design of the frame, it is not necessary to add a special member or structural part to the frame or the mask, and in a normal use form,
The same structure and function as the shadow mask having the conventional structure can be achieved.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] The embodiment shown in FIGS. 1 to 3 shows a shadow mask provided with an over-deformation prevention line. The shadow mask 10 having a substantially rectangular shape is composed of a frame 20 made of a steel material or the like, and a thin steel sheet material arranged so as to cover one surface of the frame 20 or the like. Mask 30 provided.

The frame body 20 is made of a steel material having an L-shaped cross section.
It is assembled in a rectangular shape with the L-shaped horizontal sides facing inward. The mask 30 has a gently curved shape such that the center side protrudes upward from the outer peripheral side.
The outer periphery of the mask 30 is bent downward to form a hanging edge 33, and the hanging edge 33 is fixed to the inner surface of the vertical side of the frame 20 by welding or the like.

An over-deformation prevention line 40 made of a steel wire or the like is arranged along the back surface of the mask 30. Both ends of the over-deformation prevention line 40 are inserted through through-holes 32 formed through the hanging edge 33 of the mask 30, and are fixed to the outer frame 20. The over-deformation prevention lines 40 are attached to the frame bodies 20 on both sides in a tension state in which a constant tensile force is applied. There is a certain gap over the entire length between the gently curved surface of the mask 30 and the over-deformation prevention line 40 extending linearly in the horizontal direction.

As shown in FIG. 1, the over-deformation prevention line 40 is
The frame 20 is stretched so as to connect the positions at the center of the sides facing each other in the longitudinal direction. FIG. 3 shows a state where an impact force is applied. When an impact force is applied in a direction perpendicular to the surface of the shadow mask 10, the mask 30 that has been gently curved upwardly deforms from a direction in which the mask disappears to a direction in which it is curved downwardly. Mask 3
When the mask 0 is deformed so as to protrude downward, the tip of the mask 30 comes into contact with the over-deformation prevention line 40 and attempts to deform further downward. The over-deformation prevention line 40, which is stretched horizontally in a straight line, tries to keep the posture as it is.
It shows the resistance to deformation below zero. As a result, excessive deformation of the mask 30 due to the impact force is prevented.

The over-deformation prevention line 40 is elastically deformed so as to bend downward and extend its entire length by the force applied from the mask 30, so if the above-mentioned impact force is eliminated, the over-deformation prevention line 40 will be elastically restored. This force acts to lift the mask 30 upward, thereby promoting the restoration of the mask 30 to its original shape. Since the mask 30 itself is deformed within the elastic deformation range, the mask 30 returns to the original upwardly curved state promptly by its own restoring force.

In the above embodiment, the mask 30
Was fixedly attached to the inner surface side of the frame body 20, but the mask 30 was fitted so as to cover the outer surface of the frame body 20,
A structure in which the inner surface of the mask 30 is fixed to the outer surface of the frame 20 may be employed. [Second Embodiment] The embodiments shown in FIGS. 4 and 5 show a shadow mask using partial fixing means.

As in the previous embodiment, the frame 20 and the mask 30 constitute the shadow mask 10. Mask 3
The hanging edge 33 of the outer periphery of the frame 0 is fixed to the inner surface of the frame 20. No tensile force is generated between the hanging edge 33 and the frame 20 as in a position of a connecting piece 34 described later. Mask 30
Is formed by cutting out a part of the hanging edge 33 at the center part of the side in the longitudinal direction and extending outward in the horizontal direction to form a small rectangular connecting piece 34. One side of the partial fixing piece 50 made of an L-shaped steel plate is overlapped on the connecting piece 34 and joined by welding or the like. The other piece of the partial fixing piece 50 overlaps the outside of the vertical side of the frame 20 and is joined by welding or the like. When the partial fixing piece 50 is joined to the frame 20, the connecting pieces 34, 34 attached to the opposite sides of the mask 30 are joined to the frame 20 while being pulled outward. In this state, a predetermined tensile force acts between the mask 30 and the frame 20. This tensile force may cause the frame 20 to be deformed to some extent, but does not cause the mask 30 to be excessively deformed.

FIG. 5 shows a state in which an impact force in a direction perpendicular to the plane is applied to the shadow mask having the above-described structure, and the mask 30 tends to be deformed so as to bend downward. However, as described above, since a force is applied to the mask 30 in the horizontal direction toward the frame bodies 20 on both sides in the horizontal direction, the horizontal tensile force is applied to the mask 30.
A resistance to vertical deformation of the

As a result, the deformation of the mask 30 in the vertical direction is reduced as compared with the case where no horizontal tensile force acts as described above. If the deformation of the mask 30 in the vertical direction decreases, permanent deformation hardly remains on the mask 30. [Third Embodiment] The mask 30 of the embodiment shown in FIG.
Attaches the partial fixing means shown in FIGS.

The overall shape of the mask 30 has a substantially rectangular plane shape and a cylindrical surface that is gently curved only in the longitudinal direction. Then, the center positions A and A of the long sides of the opposing side sides of the mask 30 are pulled outward and fixed to a frame (not shown). Specifically, the connecting pieces 34, 34 and the partial fixing pieces 5 (not shown) are located at the center positions A, A.
0 and 50 are arranged.

Further, of the opposing sides of the mask 30, intermediate positions B ₁ and B ₂ between the position A and the outer end thereof.
Also, pull outward and fix to the frame. Therefore, the partial fixing means is divided into three places B on one side.
₂ , A, and B ₁ . However, the tensile force of each partial fixing means is relatively large at the position A,
It is set relatively small at the B ₁ and B ₂ positions. Further, in the positions B ₁ and B ₂ , it may be set so that the pulling force does not substantially work in the mounted state, and a necessary pulling force is generated when an impact force is applied.

In the above embodiment, the deformation in the central portion of the mask 30 where the deformation in the direction perpendicular to the plane due to the impact force is greatest is strongly suppressed by the partial fixing means attached to the central position A, When the deformation is reduced, the intermediate position B at which the deformation is the next largest
Deformation of ₁ and B ₂ can also be suppressed by the partial fixing means, so that deformation of the entire mask 30 can be effectively suppressed. [Fourth Embodiment] The embodiment shown in FIG. 7 prevents the mask from being over-deformed by the deformation characteristics of the frame 20.

As shown in FIG. 7A, the basic structures of the mask 30 and the frame 20 are the same as those of the above-described embodiments, and are the same as those of a normal shadow mask. But,
As shown in FIG. 7B, when an impact force is applied to the shadow mask 10 in a direction perpendicular to the plane, the cross-sectional shape of the frame 20 is rotated from the inside to the outside so that L
Deforms so that the upper end of the vertical side of the character is curved outward.

With the deformation of the frame 20, the mask 30 joined to the inside of the vertical side of the frame 20 is pulled outward. The mask 30 attempts to deform so as to bend downward due to the impact force as described above, but the horizontal pulling force applied from the frame 20 generates a resistance to the downward deformation. ,
Excessive downward deformation is prevented. [Deformation Model of Shadow Mask] FIG. 8 shows a wire frame model for analyzing the deformation state of the shadow mask 10. Such a wire frame model is created by inputting the shape data of the shadow mask 10 into deformation analysis software of a computer.

The deformation behavior when various loads are applied to the wire frame model can be analyzed on computer data. The deformation behavior is analyzed by paying particular attention to the deformation amount between the center point P ₀ of the mask 30 and the middle point P ₁ between the center point P ₀ and the outer peripheral end on the longitudinal diameter. FIG. 9 shows the deformation behavior of a normal shadow mask 10 without any special over-deformation prevention means.

The whole of the mask 30 is curved downward like a lens, and the peripheral portion supported by the frame 20 has little deformation, but the central point P ₀ farthest from the supporting point.
Is the largest deformation. The intermediate point P ₁ is less than the center point P ₀ is deformed in significant amounts downwards. When such a large deformation occurs, the shape of the mask 30 does not return to its original shape even when the impact force is lost, and permanent deformation remains.

When the stress generated at each point of the mask 30 was analyzed at the same time as the analysis of the deformation behavior, it was found that a large stress was generated around the supporting portion of the frame 20 where the deformation of the mask 30 was not allowed. Was. In particular, the mask 30
A maximum stress is generated in a region X immediately inside the outer short side of the outer periphery. This is consistent with the location where permanent deformation is likely to occur when an impact force is applied to the actual shadow mask 10, and supports that the analysis of the deformation behavior and stress is close to the actual behavior.

FIG. 10 is a graph showing the deformation behavior over time. At the same time as the impact force is applied, the amount of deformation increases rapidly, and after the amount of deformation reaches a maximum value, it can be seen that the deformation is progressing in a direction to return to the original shape due to the reaction force. FIG. 11 shows the partial fixing piece 5 shown in FIGS.
The deformation behavior when an impact force in a direction perpendicular to the plane is applied to the shadow mask 10 having 0 is shown.

Although the entire mask 30 is deformed so as to bend downward, the portions which are pulled by the frame members 20 on both sides by the partial fixing pieces 50, that is, the rectangular mask 30 is moved in the longitudinal direction. On the center line where the light beam is divided into two, the downward deformation is sufficiently suppressed. The amount of deformation of the center point P ₀ on the center line is also small. At any point,
The amount of deformation of the mask 30 remains within the elastic deformation range, and there is no place where permanent deformation occurs. Although not shown,
The generated stress in the vicinity of the outer short side of the mask 30 is also very small.

As shown in FIG. 12, the change in the amount of deformation over time shows that the amount of deformation at both the center point P ₀ and the intermediate point P ₁ is significantly smaller than that of FIG. You can see that. Moreover, deformation of the easily center point P ₀ deformation preventing function acts directly by the partial fixing piece 50 is adapted rather less than the amount of deformation of the intermediate point P _1, the effect of preventing deformation by the partial fixing piece 50 Is large.

[0043]

The shadow mask of the present invention is provided with an over-deformation preventing line and a part fixing means, and an over-deformation preventing means by using a frame having specific deformation characteristics.
When a large impact force is applied to the shadow mask in a direction perpendicular to the plane, the problem that the mask is excessively deformed and cannot be returned to the original shape can be prevented.

In particular, since the over-deformation prevention line uses only a wire having a relatively simple shape and the structure of the partial fixing means is simple, the structure of the shadow mask becomes complicated, and the original function of the shadow mask is reduced. Less disturbing.
If only the deformation characteristics of the frame are designed, the basic structure and manufacturing are completely the same as those of the conventional ordinary shadow mask.

[Brief description of the drawings]

FIG. 1 is a perspective view of a shadow mask representing an embodiment of the present invention.

FIG. 2 is a sectional view of the upper figure.

FIG. 3 is a sectional view in an impact load state.

FIG. 4 is a perspective view of a shadow mask showing another embodiment.

FIG. 5 is a sectional view of the upper figure.

FIG. 6 is a schematic structural perspective view of a mask showing another embodiment.

FIG. 7 illustrates another embodiment when a shadow mask is not loaded.
(a) and cross-sectional view under impact load (b)

FIG. 8 is a perspective view showing a wireframe model of a shadow mask.

FIG. 9 is a perspective view of a wire frame model under an impact load when there is no over-deformation prevention means.

FIG. 10 is a diagram showing a relationship between a time lapse and a displacement at the time of an impact load in the upper diagram.

FIG. 11 is a perspective view of a wire frame model under an impact load when there is an over-deformation prevention means.

FIG. 12 is a diagram showing a relationship between a time lapse and a displacement at the time of an impact load in the upper diagram.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Shadow mask 20 Frame 30 Mask 31 Cathode ray passage part 32 Through hole 34 Connection piece 40 Over-deformation prevention line 50 Partial fixing piece

Claims (8)

[Claims] 1. A shadow mask attached to a cathode ray tube and through which a cathode ray passes, comprising: a frame attached to the cathode ray tube; a mask attached to the frame having a cathode ray passage portion; An over-deformation preventing line extending between opposing sides of the frame body at an interval from the mask. 2. The shadow mask according to claim 1, wherein the over-deformation prevention line is stretched between center portions of frame sides of the frame. 3. A shadow mask attached to a cathode ray tube and through which cathode rays pass, comprising: a frame attached to the cathode ray tube; a mask attached to the frame having a cathode ray passage portion; A shadow mask comprising: a part fixing means for fixing a pair of opposing positions to the outer frame. 4. The shadow mask according to claim 3, wherein the partial fixing means fixes the pair of positions to the frame while pulling the pair of positions outward. 5. The partial fixing means fixes the mask to the frame in a state where a tensile force is generated between the pair of positions and the frame when an external force is applied to the mask in a direction perpendicular to a plane. The shadow mask according to claim 3. 6. The mask according to claim 3, wherein said partial fixing means is arranged at a pair of positions facing each other at a center of a side of said mask.
5. The shadow mask according to any one of 5. 7. The shadow mask according to claim 3, wherein said partial fixing means is arranged at a plurality of positions on a side of said mask. 8. A shadow mask attached to a cathode ray tube and through which a cathode ray passes, comprising: a frame attached to the cathode ray tube; and a mask attached to the frame and having a cathode ray passage portion, wherein the frame is A shadow mask having a deformation characteristic of deforming so that a mounting portion of the mask expands outward when an impact force is applied in a direction perpendicular to the surface of the shadow mask.