JP2000285820A - Shadow mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an economical and easily manufactured shadow mask capable of favorably exercising both functions of a mask and a frame. SOLUTION: This shadow mask having a frame comprising a pair of oppositely placed long side frame materials 40 and a pair of short side frame materials 30 connecting the long side frame materials 40 prevents occurrence of an excessive thermal stress and a permanent set to a mask 10 due to a thermal expansion difference of upper and lower frame 42 and 44 even when using invar alloys or the like for the mask 10 and the upper frame 42 and inexpensive steel products or the like for the lower frame 44 by equipping the long side frame materials 40 with the upper frame 42 whereon the mask 10 is bonded and the lower frame 44 supporting the upper frame 42 and allowing relative expansive and contractive deformation in an axial direction of the long side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a shadow mask, and more particularly, to a shadow mask incorporated in a cathode ray tube of a color TV or the like to control passage of a cathode ray.

[0002]

2. Description of the Related Art A shadow mask has a cathode ray passage portion composed of a number of fine holes and slits. By illuminating the body,
The screen is configured as a set of fine light spots.

The general structure of a shadow mask is as follows.
It is composed of a rectangular metal frame, that is, a frame, and a mask made of a thin metal plate and formed with a hole or a slit through which a cathode ray passage portion is formed. By attaching the thin mask to the frame having high rigidity in a tensioned state, the surface state of the mask and the position of the cathode ray passage portion are accurately maintained.

As a material for the mask, an invar alloy having advantages such as excellent electromagnetic properties, little thermal expansion and deformation in a use environment, and easy processing of a cathode ray passage portion is easily used. Often. 2. Description of the Related Art In recent years, as a TV receiver, a so-called flat-panel television having a substantially flat screen has been developed as the size of a screen has been increased. In a cathode ray tube having a large and flat or nearly flat display surface used in such a TV receiver, the mask to be stuck on the shadow mask is also large, and is stuck in a precisely defined surface state close to a flat surface. Must be set up.

[0005]

In the manufacturing process of the cathode ray tube, a large amount of heat may be applied to the shadow mask. For example, there is a step of inserting an internal structural component such as a shadow mask into a front panel of a cathode ray tube, and then sealing a funnel covering a rear portion of the tube main body. In this step, since the glass is partially melted and sealed,
It is heated for about one hour at a high temperature of from ℃ to 480 ℃.

In such a high-temperature heating environment, the shadow mask causes a large thermal expansion. At this time, a difference in thermal expansion occurs due to a difference in a material constituting the shadow mask. For example, if the mask is made of an Invar alloy and the frame is made of iron, the difference in thermal expansion between the Invar alloy and iron is very large and about 10 times. This causes a problem that permanent deformation remains in the mask even after the heat treatment.

[0007] If permanent deformation remains in the mask, the position and shape of the cathode ray passage portion will be displaced, making it impossible to accurately control the passage of the cathode ray, and deteriorating the image quality of the TV screen. When used in the above-mentioned large flat-screen television, there is an extremely high demand for the surface accuracy of the mask and the arrangement accuracy of the cathode ray passage portion, and it is necessary to minimize the deformation due to the difference in thermal expansion as described above.

[0008] In addition, welding is used for attaching the mask to the frame, but there is also a problem that it is technically difficult to weld a thin mask made of Invar alloy to iron or steel. It is technically extremely difficult to weld a large-area thin mask to iron or the like in a precisely defined surface condition. If the mask and the frame are made of the same material, Invar alloy, no difference in thermal expansion occurs and welding is relatively easy. However, the material cost of Invar alloy is about four times higher than iron,
The cost of the cathode ray tube increases. In particular, it is economically burdensome to produce a large-sized frame with an expensive Invar alloy for the large flat-panel television.

If both the mask and the frame are made of iron, the cost is low. However, it is easily deformed due to thermal expansion in a use environment, and the distance between the shadow mask and the phosphor on the front panel changes, and a part of the mask is deformed, so that the passage of the cathode ray cannot be controlled accurately. For this reason,
In order to attach the iron mask to the frame in a tensioned state, it is necessary to apply a much higher tension than in the case where an Invar alloy is used. Specifically, although a mask made of an Invar alloy varies depending on the size of the cathode ray tube, for example, a tension of about 200 kg may be sufficient, but a steel mask requires a tension twice or more as large. In order to receive such a large tension, the strength of the frame must be increased, which increases the bulk and weight of the frame.

It is an object of the present invention to provide a shadow mask which can exhibit both functions of a mask and a frame well and can be economically and easily manufactured.

[0011]

A shadow mask according to the present invention is a shadow mask having a rectangular frame attached to the inner wall of a cathode ray tube, and a mask attached to the frame and having a cathode ray passage portion. The frame body is composed of a pair of long side frame members arranged to face each other and a pair of short side frame members connecting the long side frame members. The long side frame material has an upper frame portion on which a mask is stuck,
And a lower frame portion that supports the upper frame portion while permitting relative expansion and contraction in the axial direction. [Cathode ray tube] It is applied to a cathode ray tube used for various ordinary uses. For example, there are a TV receiver, a computer display, and various instrument displays.

The shadow mask of the present invention is suitably used for a cathode ray tube having a large display surface and a flat surface. For example, the present invention is applied to a flat screen television having a large screen exceeding 25 inches. The basic structure of a cathode ray tube is the same as that of a normal cathode ray tube, and a control mechanism for an electron gun and an electron beam is installed in a rear funnel of a cathode ray tube having a funnel shape. A shadow mask is attached to a front panel disposed in front of the rear funnel, and is sealed to the rear funnel. [Shadow Mask] The shadow mask is composed of a mask having a cathode ray passage portion through which a cathode ray passes, and a frame body that supports the mask at a precise position and posture under tension.

The mask has the same material and basic structure as those used in a normal cathode ray tube. The mask may be attached to the frame in a completely flat state, or may be a curved surface that is gently curved in one direction. The material of the mask is generally made of an Invar alloy, but may be made of another low thermal expansion metal material as long as it can function as a mask.

The invar alloy is a low thermal expansion metal mainly composed of iron and nickel, and there are various alloy compositions including, for example, 64% iron.
Are known in which nickel is combined with 36%, and the above composition is further added with cobalt. The thermal expansion coefficient of the Invar alloy is very small, about 1.7 × 10 ⁻⁶ K ⁻¹ , which is about 1/7 compared to about 12 × 10 ⁻⁶ K ⁻¹ of iron.

The frame has a mounting structure such as a metal fitting for mounting and fixing the shadow mask to the inner wall of the cathode ray tube. The frame body has a substantially rectangular overall planar shape, and is composed of a pair of long side frame members arranged opposite to each other and a pair of short side frame members connecting the long side frame members. As described later, the long side frame material needs to have a structure for supporting the mask, but the short side frame material connects the opposing long side frame materials to maintain a constant interval. I just want to keep. Therefore, the material and structure of the short side frame material are not particularly limited in terms of maintaining the shape of the mask after being pasted, and iron or steel molds can be used as they are. [Long side frame material] The long side frame material includes an upper frame portion on which a mask is stuck and a lower frame portion supporting the upper frame portion.

The upper frame portion may be provided with a material and a shape structure suitable for attaching a mask. Not much rigidity is required for the upper frame. Most simply, it may be an elongated strip, and if necessary, may be provided with a shape structure for supporting to a lower frame portion described later. The shape of the upper end surface of the upper frame portion is manufactured according to the surface shape of the mask, and is a straight line or a gentle curved line.

Usually, the upper frame portion is preferably made of the same material as the mask. However, a metal material different from the mask may be used as long as the mask can be easily welded and has the same thermal expansion characteristics as the mask. It can also be used. Specifically, the mask and the upper frame portion can be made of the same Invar alloy. To reduce material costs, the dimensions of the upper frame
It is preferable to make the mask as small as possible within the range where the attachment of the mask and the support to the lower frame portion are possible.

The lower frame supports the mask attached to the upper frame in an accurate position and shape by supporting the upper frame. The tension applied to the mask is transmitted to the lower frame via the upper frame. Therefore, the lower frame portion needs to have a structure that can withstand the tension. Since the tension acts in a direction orthogonal to the axial direction of the lower frame, the lower frame preferably has a structure and a material having high rigidity in the direction orthogonal to the axis.

For the lower frame portion, a metal mold material or a pressed material is used. The material of the lower frame is not restricted like the upper frame,
Metal materials for various structures can be used as long as they have sufficient rigidity to support the mask and the upper frame portion, and materials that are easy to process and manufacture and that are inexpensive are preferable. Specifically, iron or steel is used. [Expansion and Deformation Permitting Means] The long side frame member may be provided with a means for supporting the upper frame portion on the lower frame portion while permitting relative expansion and contraction deformation in the axial direction of the long side.

Specifically, it is possible to provide a sliding protrusion at the lower end of the upper frame portion and a sliding groove at which the sliding protrusion can slide at the upper end of the lower frame portion. Sliding of the upper frame with respect to the lower frame allows relative expansion and contraction. However, it is necessary to reliably restrict movement and deformation of the upper frame portion and the lower frame portion in a direction perpendicular to the axis. As the shape and structure of the sliding convex portion and the sliding groove, a sliding structure between members in a normal mechanical device can be adopted. For example, when the sliding protrusion and the sliding groove are T
If it is formed in a letter shape, both can slide smoothly, and the sliding protrusion does not come off from the sliding groove, so that it can easily withstand a load in a direction perpendicular to the axial direction.

The sliding protrusions and the sliding grooves may be formed integrally with the upper frame or the lower frame, or the members constituting the sliding protrusions or the sliding grooves may be formed by the upper frame or the lower frame. It may be adapted to be attached to. The sliding convex portion and the sliding groove may be provided continuously over the entire length of the long side frame material, or may be provided partially. For example, it may be provided only near the center and both ends of the long side frame material.

For example, a receiving piece which forms a sliding groove between the outer surface of the lower frame portion and the outer surface can be provided. The receiving piece can be formed of the same material as the lower frame portion. The receiving piece may be provided in a part of the lower frame portion, for example, only near both ends. As the expansion / contraction deformation permitting means, a sliding pin can be provided in the upper frame portion and a sliding long hole into which the sliding pin is inserted and extends in the axial direction can be provided in the lower frame portion. Since the sliding pin can relatively move within the range of the sliding slot, relative expansion and contraction of the upper frame portion and the lower frame portion can be allowed in that range.

The sliding pin may have a simple rod shape with a circular or square cross section, or a shape having a head such as a bolt or a rivet. The upper frame portion and the lower frame portion may be allowed to move relative to each other at all points in the axial direction to allow expansion and contraction, and it is necessary to prevent occurrence of excessive stress and distortion due to a difference in thermal expansion. Means for permitting expansion and contraction may be provided only at certain locations.

It is preferable that a positioning means is provided so that the upper frame and the lower frame are not displaced from each other even if the upper frame and the lower frame deform. For example, if the upper frame portion is fixed to the lower frame portion at the center in the axial direction, and is supported so as to be relatively movable with respect to the lower frame portion on both sides of the fixed portion, the upper frame portion is relative to the lower frame portion. The displacement can be prevented and the upper frame can be freely expanded and contracted with respect to the lower frame.

The fixing or positioning of the upper frame portion and the lower frame portion can be achieved by spot welding. Such welding for partial fixing or positioning does not cause any problem even if the materials of the upper frame portion and the lower frame portion are different.
Fastening with bolts and rivets is also available. The upper and lower frame portions may be provided with engaging concave and convex portions that can engage with each other. [Easily deformable portion] The lower frame portion is provided with an easily deformable portion that facilitates deformation in the axial direction, thereby absorbing a difference in thermal expansion between the upper frame portion and the lower frame portion by the deformation of the lower frame portion. be able to.

The easily deformable portion is provided only at a portion of the lower frame portion that supports or fixes the upper frame portion and its periphery, and at other portions, the lower frame portion has sufficient rigidity. It is preferable to keep it. As the easily deformable portion, a shape portion, such as a notch, a through hole, a recessed portion, or a thin portion, which reduces mechanical deformation resistance may be provided in a part of the lower frame portion.

As the easily deformable portion, slits which are arranged at a plurality of positions along the axial direction of the lower frame portion and are cut out from the upper end of the lower frame portion to the middle can be used. By forming the slit in the lower frame portion having a rod shape or a frame shape, the portion where the slit is formed is easily deformed in the axial direction. If the slit is formed only halfway in the cross-sectional shape of the lower frame portion, sufficient rigidity can be exhibited in the portion without the slit. Further, at the location where the slit is formed, the deformation in the direction in which the slit narrows or expands, that is, the axial direction of the lower frame portion is facilitated, but the rigidity in the direction orthogonal to the axis does not decrease. This is where there is no slit
This is because a load applied in a direction perpendicular to the axis can be opposed in the entire cross-sectional shape of the lower frame portion.

By appropriately setting the notch depth and width of the slit and the interval between the slits, the deformation characteristics of the lower frame portion can be adjusted. Specifically, the lower the notch depth, the wider the slit, and the smaller the interval between the slits, the easier the lower frame portion is to be deformed in the axial direction.
Further, when the ratio of the slit to the entire length of the lower frame portion increases, the rigidity in the direction perpendicular to the axial direction also decreases. Therefore, the arrangement structure of the slit is designed to maintain the rigidity necessary for supporting the mask.

The slits may be arranged with the same shape and interval over the entire length of the lower frame portion, or the arrangement shape may be changed depending on the location. Normally, thermal stress and distortion due to a difference in thermal expansion between the lower frame portion and the upper frame portion become larger as approaching both ends with reference to the center in the axial direction. Therefore, it is effective to provide easily deformable portions for absorbing the difference in thermal expansion near both ends in the axial direction.

The notch depth of the slit can be made deeper at both ends than at the center in the axial direction of the lower frame portion. As a result, the deformation of the lower frame portion is increased at both ends where the slit is deep, and the difference in thermal expansion can be efficiently absorbed. The same effect can be achieved even if the interval between the slits is made narrower at both ends than the axial center of the lower frame portion.

Both the depth and the interval of the slit may be made deeper and narrower at both ends with respect to the axial center of the lower frame. The slits may be provided only near both ends in the axial direction of the lower frame portion. When the easily deformable portion as described above is provided, the upper frame portion and the lower frame portion may be joined over the entire length, or may be partially joined.

The long side frame member can be provided with both the above-mentioned elastic deformation permitting means and the easily deformable portion.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [T-shaped expansion / contraction deformation permitting means] The shadow mask shown in FIGS. 1 and 2 is composed of a mask 10 and a frame 20. The mask 10 is made of a thin sheet material of an Invar alloy, has a rectangular shape as a whole, and has a fine circular or oblong cathode ray passage hole 1 over almost the entire surface except the periphery.
2 are arranged.

The frame 20 has a substantially rectangular shape as a whole, and a pair of long side frame members 4 which are disposed to face each other and support the mask 10.
0 and a pair of short-side frame members 30 that connect and support the opposing long-side frame members 40 while maintaining a constant interval. The long side frame member 40 is made of the same Invar alloy as the mask 10, and is made of an upper frame portion 42 having side edges of the mask 10 adhered by welding or the like, and a mold steel material, and slides on the upper frame portion 42. And a lower frame portion 44 that supports as possible. Lower frame part 44
Is welded to a short-side frame member 30 made of a U-shaped cross section steel to form a rectangular frame 20.

As shown in detail in FIG. 2, the lower end of the upper frame portion 42 is a sliding convex portion 43 having a T shape (arranged in an inverted T shape in the figure). At the upper end of the lower frame portion 44,
A T-shaped slide groove 45 into which the slide protrusion 43 is inserted is provided, and the slide protrusion 43 and the slide groove 45 are fitted to each other. As a result, the upper frame portion 42 can freely slide in the axial direction with respect to the lower frame portion 44, and its movement is reliably restricted in the direction perpendicular to the axis. The upper frame 42 does not come off the lower frame 44.

As shown in FIG. 1, at the center of the long side frame member 40 in the longitudinal direction, the upper frame portion 42 and the lower frame portion 44
6 for fixing. Therefore, in a normal state, the upper frame portion 42 or the mask 10 does not move or shift with respect to the lower frame portion 44. When attaching the mask 10 to the upper frame portion 42 at the time of manufacturing the shadow mask, the mask 10 is attached in a state where the mask 10 is strongly tensioned in the short side direction. Therefore, a restoring force of the mask 10 is applied to the upper frame portion 42 in a direction orthogonal to the axial direction, and this force is applied from the upper frame portion 42 to the short side frame member 30 via the lower frame portion 44.
Supported by

In the above-described embodiment, in the manufacturing process of the cathode ray tube, if there is a large change in the temperature environment of the shadow mask, the mask 10 and the upper frame portion 42 made of the Invar alloy, and the lower frame portion 44 made of steel A difference in thermal expansion occurs between the two. For example, when heated to a high temperature, the lower frame portion 4 having a larger coefficient of thermal expansion than the mask 10 and the upper frame portion 42 side.
4 will grow much more. However, lower frame 4
4, the mask 10 and the upper frame 42 can be freely moved relative to each other in the axial direction. It can freely expand and contract on both sides, and can prevent the occurrence of excessive thermal stress and permanent deformation.

When the heating step is completed and the temperature returns to the normal temperature environment, the mask 10 and the upper frame portion 42 return to the original state. Also at this time, since the positions of the upper frame portion 42 and the lower frame portion 44 are determined by fixing with the welding portion 46, there is no fear of causing a positional shift. [Expansion and Deformation Permitting Means of Pin and Slot] The shadow mask shown in FIGS. 3 and 4 has the same basic structure as that of the above-described embodiment, but differs in the structure of the expansion and contraction permitting means.

The upper frame portion 42 on which the mask 10 is stuck has a long and narrow strip shape, and a long hole 52 extending in parallel with the axial direction penetrates near both ends in the axial direction. The lower frame portion 44 is formed by bending a steel plate material by press working, and as shown in FIG. 4, the cross section is substantially J-shaped, and the tip of the lower side is folded back to the vertical side, and the cross section is triangular. It forms a closed space. This shape can exhibit high rigidity against a force that attempts to deform the lower frame portion 44 in a direction perpendicular to the axis.

The upper part of the outer peripheral side surface of the lower frame part 44 is
2 are arranged on the inner peripheral side surface. At the center of the vertical side of the lower frame portion 44, near both ends in the axial direction, a sliding pin 54 is attached so as to protrude outward. Sliding pin 5
4 is inserted into the long hole 52 of the upper frame portion 42. A head 5 having a diameter larger than the width of the long hole 52 is provided at the tip of the sliding pin 54.
5 so that the upper frame 42 is sandwiched between the head 55 and the outer surface of the lower frame 44.

As shown in FIG. 3, a welding portion 46 for welding the upper frame portion 42 and the lower frame portion 44 is provided at the center of the long side frame member 40 in the axial direction. The frame 42 and the lower frame 44 are completely fixed. In the above embodiment, similarly to the description of the above embodiment, when the shadow mask is heated, the lower frame portion 44 extends in the axial direction of the long side frame member 40 with respect to the upper frame portion 42 and the mask 10, Absorbs the difference in thermal expansion and prevents excessive thermal stress and permanent deformation. [Expansion and Deformation Permitting Means by Receptacle] The embodiment shown in FIGS. 5 and 6 has the same basic structure as that of the above-described embodiment, but differs in the structure of the expansion and contraction allowing means.

A receiving piece 62 is attached near both ends of the lower frame portion 44. As shown in detail in FIG.
It has an L-shaped cross section, and the lower end is fixed to the outer surface of the lower frame portion 44. A sliding groove 64 is formed between the vertical side of the receiving piece 62 and the outer surface of the lower frame portion 44. The lower end of the upper frame portion 42 is inserted into the sliding groove 64 of the receiving piece 62 and is guided so as to be freely slidable. As shown in FIG. 5, at the center of the long side frame member 40, the upper frame portion 42 and the lower frame portion 44 are fixed by the welding portion 46. [Easily Deformable Portion] The embodiment shown in FIGS. 7 and 8 has the same basic configuration as that of the above embodiment, and has an easily deformable portion in the lower frame portion.

As shown in FIG. 8, the lower frame portion 44 is made of a die steel material having a right-angled triangular cross section, and has a slit 72 formed by a vertical notch extending from the upper end to halfway in the height direction.
A large number are provided at intervals along the axial direction of the lower frame portion 44. The upper frame portion 42 is made of the same Invar alloy as the mask 10, and is arranged above the outer surface of the lower frame portion 44 in which the slit 72 is formed. As shown in FIG. 7, the upper frame portion 42 is fixedly joined to the lower frame portion 44 by welding portions 46 provided at three locations near the center and both ends in the axial direction of the upper frame portion 42.

According to the above-described embodiment, when the shadow mask is subjected to a heat treatment to cause a difference in thermal expansion between the mask 10 and the upper frame portion 42 and the lower frame portion 44, the mask 10 and the upper The lower frame portion 44 can be deformed to some extent according to the frame portion 42. More specifically, the material of the lower frame portion 44 tends to expand significantly by heating and heating, but since the upper frame portion 42 does not expand so much, the expansion of the lower frame portion 44 is suppressed by deformation by the slit 72.

This is because the slit 72 that divides the lower frame portion 44 in the axial direction makes it easier for the lower frame portion 44 to be deformed in the axial direction, particularly the upper portion where the slit 72 exists. In other words, even if the lower frame portion 44 is made of a steel material that is not easily deformed as a material, the lower frame portion 44 is easily deformed by the slit 72, and a certain degree of deformation is allowed following the mask 10 made of the Invar alloy and the upper frame portion 42,
Excessive thermal stress and permanent deformation due to the difference in thermal expansion do not occur in the mask 10 and the upper frame portion 42. When the temperature is returned to room temperature after the heating is completed, the difference in thermal expansion between the mask 10, the upper frame portion 42, and the lower frame portion 44 disappears, and the deformation of the lower frame portion 44 that has been deformed to absorb the difference in thermal expansion is also reduced. Return to

The lower frame portion 44 is easily deformed to some extent in the axial direction by the slit 72, but the rigidity in the direction perpendicular to the axial direction does not decrease so much. this is,
This is because the intermediate portion where the slit 72 is not formed maintains a triangular cross-section that is not easily mechanically deformed, and the slit 72 does not reduce the rigidity. as a result,
Since the mask 10 is kept in tension, the mask 10 can sufficiently withstand a force applied to the upper frame portion 42 in a direction perpendicular to the axial direction of the long side frame member 40. [Modification of Slit] The embodiment shown in FIG. 9 is different from the above embodiment in the arrangement structure of the slit.

In the embodiment shown in FIG.
2 are arranged along the axial direction of the lower frame portion 44, but the depth D differs depending on the location. Lower frame part 44
At the center of the slit 72, the depth D of the slit 72 is the shallowest. As going from the center to the left and right sides, the depth D of the slit 72 gradually increases, and the slits 72 at both ends are the deepest. The width of the slit 72 and the interval between the slits 72 are equal.

In the above embodiment, the depth D of the slit 72
The deeper the portion, the easier the lower frame portion 44 is to be deformed in the axial direction, so that both ends are more easily deformed in the axial direction than the center of the lower frame portion 44. The above-mentioned difference in thermal expansion becomes larger as the upper frame portion 42 becomes more outward from the center fixed to the lower frame portion 44. Therefore, in order to absorb the difference in thermal expansion by deformation of the lower frame portion 44, the lower frame portion 44 is required. The larger the outside, the closer to the ends, the greater the deformation. Therefore, as described above, if the arrangement structure of the slit 72 that is more easily deformed toward the outside is provided,
The effect of absorbing the thermal expansion difference can be efficiently exhibited.

In the embodiment shown in FIG.
2 are the same in depth and width, but the distance from one slit 72 to the next slit 72, ie, the pitch P
However, it is wide at the center in the axial direction of the lower frame portion 44 and narrows toward the outside. The smaller the interval between the slits 72, the higher the deformability of that portion. Accordingly, the lower frame portion 44 is more likely to be deformed on the outer side where the interval between the slits 72 is narrower than on the center where the interval between the slits 72 is wider. As a result, the thermal expansion difference can be efficiently absorbed as described above.

Although not shown, it is also possible to change both the depth D and the interval P of the slit 72 arranged in the lower frame portion 44 from the center in the axial direction to the outside. [Combination of easy deformation part and expansion / contraction deformation permitting means] FIG.
The embodiment shown in FIG. 9 has the same basic configuration as the above embodiment, and an easily deformable portion by the slit 72;
It has both a sliding convex part 43 and a means for permitting expansion and contraction by a sliding groove 45.

The arrangement structure of the slit 72 is the same as that of the embodiment shown in FIGS. 7 and 8, and the configuration of the sliding projection 43 and the sliding groove 45 is the same as that of the embodiment shown in FIGS. Description is omitted. The welding portion 46 for fixing the upper frame portion 42 to the lower frame portion 44 may be provided only at the center in the axial direction, or may be provided at a plurality of positions in the axial direction. In the above embodiment, the mask 10, the upper frame 42 and the lower frame 4
The difference in thermal expansion from the lower frame portion 4 is caused by both the action of the upper frame portion 42 sliding and extending with respect to the lower frame portion 44 and the lower frame portion 44 being deformed in accordance with the expansion of the upper frame portion 42. Will be absorbed.

[0052]

According to the shadow mask of the present invention, even if the material of the mask is different from that of the frame in consideration of necessary functions and various conditions such as material cost, the shadow mask is generated by a heat treatment due to a difference in coefficient of thermal expansion of the material. The difference in thermal expansion between the members can be efficiently absorbed, and it is possible to prevent excessive stress and permanent deformation from occurring in the mask due to the difference in thermal expansion, thereby preventing the performance of the cathode ray tube and the image quality of the TV receiver from deteriorating.

In particular, if an invar alloy having the same thermal expansion characteristics is used for the material of the mask and the upper frame, and a low-cost material such as iron is used for the lower frame, the shadow mask function is not impaired. The manufacturing cost of the entire mask can be significantly reduced.

[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 an enlarged sectional view of a main part.

FIG. 3 is a side view showing another embodiment.

FIG. 4 is an enlarged sectional view of a main part.

FIG. 5 is a side view showing another embodiment.

FIG. 6 is an enlarged sectional view of a main part.

FIG. 7 is a perspective view showing another embodiment.

FIG. 8 is an enlarged sectional view of a main part.

FIG. 9 illustrates another embodiment, a side view from the inside out.

FIG. 10 is a perspective view showing another embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Mask 12 Cathode ray passage hole 20 Frame 30 Short side frame material 40 Long side frame material 42 Upper frame part 43 Sliding convex part 44 Lower frame part 45 Sliding groove 46 Welding part 52 Sliding long hole 54 Sliding pin 62 Receiving Piece 72 slit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Ayumu Takakuwa 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5C031 EE08 EE11

Claims (12)

[Claims] 1. A shadow mask comprising: a rectangular frame attached to an inner wall of a cathode ray tube; and a mask affixed to the frame and having a cathode ray passage portion, wherein the frame is a pair of opposingly arranged frames. A long-side frame member and a pair of short-side frame members connecting the long-side frame member, wherein the long-side frame member is positioned relative to an upper frame portion to which the mask is attached, in the axial direction of the long side. A shadow mask comprising: a lower frame portion that supports the upper frame portion while permitting a proper expansion and contraction deformation. 2. As means for allowing the expansion and contraction deformation,
The shadow mask according to claim 1, wherein the upper frame portion includes a sliding protrusion, and the lower frame portion includes a sliding groove in which the sliding protrusion can slide. 3. The shadow mask according to claim 2, wherein the sliding convex portion and the sliding groove have a T-shaped cross section. 4. The shadow mask according to claim 2, wherein the sliding groove is formed between a receiving piece protruding from an outer surface of the lower frame portion and an outer surface of the lower frame portion. 5. As means for allowing the expansion and contraction deformation, a slide pin is projected from the upper frame portion, and the slide pin is inserted into the lower frame portion and extends in the axial direction of the lower frame portion. The shadow mask according to claim 1, further comprising a moving slot. 6. The apparatus according to claim 1, wherein the upper frame portion is fixed to the lower frame portion at the center in the axial direction, and is supported on both sides of the fixing portion so as to be relatively movable with respect to the lower frame portion. The shadow mask described in Crab. 7. A shadow mask comprising: a rectangular frame attached to the inner wall of a cathode ray tube; and a mask affixed to the frame and having a cathode ray passage portion, wherein the frame is a pair of oppositely disposed frames. A long-side frame member, and a pair of short-side frame members connecting the long-side frame member, wherein the long-side frame member has an upper frame portion to which the mask is attached, and a lower frame for fixing the upper frame portion. Department and
A shadow mask in which the lower frame portion includes an easily deformable portion that facilitates deformation in an axial direction. 8. The shadow mask according to claim 7, wherein the easily deformable portions are slits which are arranged at a plurality of positions along the axial direction of the lower frame portion, and are cut out from the upper end of the lower frame portion to the middle. 9. The shadow mask according to claim 8, wherein the notch depth of the slit is deeper at both ends in the axial direction of the lower frame than at the center. 10. The shadow mask according to claim 8, wherein an interval between the slits is smaller at both ends in the axial direction of the lower frame portion than at a center. 11. The upper frame portion is made of a material having substantially the same thermal expansion property as the mask, and the lower frame portion is made of a material having a different thermal expansion property from the upper frame portion and the mask.
0. The shadow mask according to any one of 0. 12. The upper frame portion is made of an invar alloy,
The shadow mask according to claim 1, wherein the lower frame portion is made of iron.