JP2001057162A - Color picture tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a color picture tube for displaying an image, having good color purity by reducing the positional deviation of a shadow mask in relation to a panel and the deformation of a mask body, due to thermal expansion of a mask frame an by reducing the deformation of a mask frame mounting part of the mask body. SOLUTION: In this color picture tube, slit slots 31, each having a length of 3% or larger of the diagonal effective diameter of a shadow mask, are formed on the edge side of a skirt part 27 in the vicinity of the short axis of a mask body 28, fixing points 33 to a mask frame 29 are formed in the vicinity of the edge of the skirt part 27 on the opposite side of the short axis end to the slit slots, and the distance between the fixing points 33 and the slit slots 31 is set to 1/2 or smaller of the length of the slit slots 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color picture tube and, more particularly, to a color picture tube in which deterioration of color purity caused by displacement or deformation of a mask body with respect to a mask frame due to thermal expansion of the mask frame or the like is reduced. About pipes.

[0002]

2. Description of the Related Art Generally, a color picture tube has an envelope consisting of a substantially rectangular panel and a funnel funnel,
The three electron beams emitted from the electron gun disposed in the neck of the funnel are deflected by the deflection yoke mounted on the outside of the funnel, and are deflected to the inner surface of the effective portion of the panel via a substantially rectangular shadow mask. The phosphor screen formed of the provided three-color phosphor layers is horizontally and vertically scanned to form a color image.

The above-mentioned shadow mask is a color selection electrode for selecting three electron beams emitted from an electron gun so as to properly land on the three-color phosphor layer. As shown in FIG. A large number of electron beam passage holes 2 are provided in an effective surface 1 facing the provided phosphor screen, and a skirt portion 3 is formed on the outer periphery of the effective surface 1 by bending so as to have a thickness of about 0.1 to 0.3 mm. And a substantially rectangular mask frame 5 attached to the skirt portion 3 of the mask body 4, and an elastic support (see FIG. 1) attached to the mask frame 5. (Not shown) is engaged with a stud pin (not shown) provided on the panel to be supported inside the panel.

In order to display an image with good color purity on a phosphor screen in a color picture tube,
It is necessary to prevent the shape change of the shadow mask and to keep the shadow mask within a predetermined allowable range with respect to the panel. Otherwise, the color purity is degraded due to the shape change and position change.

However, the shadow mask is irreversibly deformed due to a difference in thermal expansion between the mask main body 4 and the mask frame 5 due to heating during the manufacturing process of the color picture tube or an attached state, or is deformed due to an external force such as impact or vibration. Great potential. Further, when the phosphor screen is formed by a photo printing method using a shadow mask as an optical mask, if the mask body 4 is displaced with respect to the mask frame 5, the three-color phosphor layer is displaced from an appropriate position, and the electron beam Will not land properly on the three-color phosphor layer, and the color purity will be degraded. During operation of the color picture tube, the mask body 4 and the mask frame 5 thermally expand due to the collision of the electron beam. When the collision time of the electron beam is short, the thermal expansion due to the collision of the electron beam mainly heats the mask main body 4, and the mask main body 4 expands more thermally than the mask frame 5. When the mask main body 4 and the mask frame 5 are made of a material having a similar coefficient of thermal expansion, the mask main body 4 mainly thermally expands at the start of the operation of the color picture tube, and the central portion of the mask main body 4 faces the phosphor screen direction. The so-called doming phenomenon of swelling occurs, and the landing of the electron beam on the phosphor layer shifts, thereby deteriorating the color purity.

As for the deterioration of color purity due to the doming, a mask body 4 made of a low thermal expansion coefficient material such as amber (iron-nickel alloy) to prevent the doming phenomenon has been put to practical use. Normally, in this shadow mask, a mask frame 5 is formed of a cold-rolled steel plate having a larger coefficient of thermal expansion than a mask body 4 made of a material having a low coefficient of thermal expansion.

For this reason, in the shadow mask, when the color picture tube is operated for a long time, the mask frame 5 expands more thermally than the mask main body 4 due to the heat transfer from the mask main body 4, which is opposite to the above-mentioned doming phenomenon. The mask main body 4 is pulled by the mask frame 5 and causes a phenomenon that can be called a reverse doming phenomenon. In order to prevent the reverse doming phenomenon from occurring, the mask frame 5 may be formed of a material having a low coefficient of thermal expansion.
Is thicker than the mask body 4, which leads to an increase in cost.

Therefore, in a shadow mask in which the mask body 4 is made of a material having a low thermal expansion coefficient and the mask frame 5 is made of a material having a larger thermal expansion coefficient, as shown in FIG. A notch groove 7 is provided on the open edge side of the tongue piece 8 to form a tongue piece 8, and a mask frame is welded to the tongue piece 8.

In this case, the width a and the length b (length of the cut groove 7) of the tongue piece 8 are

## EQU1 ## The following relationship is established: a <2b, and two points indicated by crosses near the open end of the tongue piece 8 are welded to the mask frame by fixing them to the mask frame. Thus 2
When welding is performed at points, the suppression force against rotation of the mask body with respect to the mask frame about the vertical axis of the plate surface of the skirt portion 3 can be made greater than when welding is performed at one point, and the position of the shadow mask with respect to the panel can be increased. The displacement can be reduced. Further, when a force is applied in a direction perpendicular to the plate surface of the skirt portion 3, that is, when the skirt portion 3 is pulled in a direction perpendicular to the plate surface due to thermal expansion of the mask frame or the like, the tongue piece portion 8 is applied to the tongue piece portion 8. The force is concentrated, and the influence of the tensile force on the entire mask body can be reduced.

The skirt 3 of the mask body is
It has the effect of increasing the curved surface holding strength of the effective surface, and by increasing the width of the skirt portion 3, the curved surface holding strength of the effective surface can be increased. For this reason, in order to improve the visibility, the effective portion of the panel is flattened, and the shadow mask in which the effective surface of the mask body is flattened with the flattening of the panel has a relatively large effective surface. The width of the skirt is larger than that of a conventional mask body having a curvature. However, when the width of the skirt portion is increased, the strength of the tongue piece portion formed in the relationship of Expression 1 is reduced. In addition, the thickness of the mask body is increased by increasing the thickness of the mask body in order to increase the curved surface holding strength of the effective surface, and the tongue piece is easily deformed.

Therefore, in such a shadow mask, as shown in FIG. 7 (b), the fixing point 9 with the mask frame indicated by the mark “x” is separated from the open edge of the skirt portion 3 to substantially reduce the tongue. The mask frame is attached by a method of shortening the length of the piece 8.

By attaching the mask frame in this manner, the strength of the tongue piece 8 of the shadow mask whose effective surface is flattened is prevented from being reduced, and this occurs when an external force such as impact or vibration is applied to the shadow mask. The displacement of the mask body with respect to the mask frame can be reduced. However, when the mask frame is attached as described above, the thermal expansion of the mask frame greatly affects the mask body when the mask body is pulled in a direction perpendicular to the plate surface of the skirt portion 3, and the mask body has The effect of preventing deformation is reduced.

[0013]

As described above, at the start of the operation of the color picture tube, the mask main body is formed of a material having a low coefficient of thermal expansion in order to prevent the doming phenomenon that occurs mainly due to the thermal expansion of the mask main body. Things have been put to practical use. However, if only the mask body is formed of a material having a low coefficient of thermal expansion and the mask frame is formed of a material having a larger coefficient of thermal expansion, when the color picture tube is operated for a long time, the mask is transmitted by heat from the mask body. The mask frame expands more thermally than the main body, and a reverse doming phenomenon occurs that is opposite to the above-described doming phenomenon in which the mask main body is pulled by the mask frame.

Therefore, in this shadow mask, a notch groove is provided on the open edge side of the skirt portion of the mask body to form a tongue piece, and two points of the tongue piece are welded as fixing points to the mask frame. Thus, the mask frame is attached to the mask body. When the mask frame is attached in this manner, the rotation suppressing force of the mask body with respect to the mask frame about the axis perpendicular to the plate surface of the skirt portion can be made larger than when welding is performed at one point. Also, when the skirt is pulled in the direction perpendicular to the plate surface due to thermal expansion of the mask frame, etc., the force concentrates on the tongue piece,
The influence of the tensile force on the entire mask body can be reduced.

However, in a shadow mask in which the effective surface is flattened to be incorporated into a panel in which the effective portion is flattened in order to improve visibility, the skirt portion of the mask main body is formed in order to increase the strength of holding the curved surface of the mask main body. Because the width of the tongue is large, the strength of the tongue piece decreases. In addition, the thickness of the mask body is increased by increasing the thickness of the mask body in order to increase the strength of retaining the curved surface of the effective surface, and the tongue piece is easily deformed.

For this reason, in such a shadow mask, the fixing point of the mask body to the mask frame is separated from the open edge of the skirt portion, and the mask frame is attached by a method of substantially shortening the length of the tongue piece. ing. However, when the mask frame is attached in this manner, the mask frame thermally expands, and when the mask body is pulled in a direction perpendicular to the plate surface of the skirt portion, the influence on the mask body is increased, and the mask body is deformed. There is a problem that the prevention action is reduced.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is possible to reduce the displacement of a mask main body due to a positional shift of a shadow mask with respect to a panel and the thermal expansion of the mask frame, and to attach the mask main body to the mask frame. It is an object of the present invention to configure a color picture tube that displays an image with good color purity by reducing the deformation of the section.

[0018]

(1) A substantially rectangular shadow mask is arranged to face a phosphor screen provided on an inner surface of an effective portion of a substantially rectangular panel. A substantially rectangular mask body in which a number of electron beam passage holes are provided, a skirt portion is bent on the outer periphery of the effective surface facing the phosphor screen, and a plurality of cut grooves are provided in the skirt portion. When,
In a color picture tube comprising a mask frame attached to the mask body with the vicinity of the cut groove of the skirt portion as a fixed point, the cut groove has a length of 3% or more of the diagonal effective diameter of the shadow mask near the short axis of the mask body. This cut groove does not have a fixing point with the mask frame on the short axis end side, but has a fixing point with the mask frame near the edge of the skirt portion opposite to the short axis end. The distance between the fixing point and the cut groove was set to be not more than の of the length of the cut groove.

(2) In the color picture tube of (1),
One or at least two cut grooves are provided on the short axis of the mask body with the short axis of the mask body interposed therebetween, and the mask frame is attached to these cut grooves at two fixed points. Is set to 2/3 or more of the width of the skirt portion and 1/5 or less of the minor axis diameter of the effective surface of the mask body.

(3) A substantially rectangular shadow mask is disposed facing the phosphor screen provided on the inner surface of the effective portion of the substantially rectangular panel, and this shadow mask passes through a large number of electron beams. A substantially rectangular mask body in which a hole is provided and a skirt portion is bent and formed on the outer periphery of the effective surface facing the phosphor screen, and the skirt portion is provided with a plurality of cut grooves, In a color picture tube comprising a mask frame attached to the mask body with the vicinity of the cut groove as a fixed point, the cut groove is formed near the major axis of the mask body at a length of 3% or more of the diagonal effective diameter of the shadow mask. The cut groove has no fixed point with the mask frame on the long-axis end side, but has a fixed point with the mask frame near the edge of the skirt portion on the opposite side of the long-axis end. The distance between the groove and the cut groove was set to be not more than の of the length of the cut groove.

(4) In the color picture tube of (3),
At least two notches are provided on the long axis of the mask body with one or the long axis of the mask body interposed therebetween, and the mask frame is attached to these notches at two fixed points. Is set to 2/3 or more of the width of the skirt portion and 1/5 or less of the minor axis diameter of the effective surface of the mask body.

(5) In the color picture tube according to any one of (1) to (4), the length of the cut groove is set to 40% or more of the width of the skirt.

(6) In the color picture tube according to any one of (1) to (5), the outer surface of the effective portion of the panel is a flat surface or a flattened curved surface having a slight curvature.

[0024]

FIG. 1 shows a color picture tube according to an embodiment of the present invention. This color picture tube has a substantially rectangular flattened panel 12 in which a skirt portion 11 is provided around an effective portion 10 whose outer surface is a flat surface or a curved surface having a slight curvature, and a funnel-shaped funnel 13. And an envelope consisting of: On an inner surface of the effective portion 10 of the panel 12, a phosphor screen 14 including a three-color phosphor layer that emits blue, green, and red light is provided. A substantially rectangular shadow mask 15 is disposed opposite the phosphor screen 14, and an elastic support 16 attached to a mask frame, which will be described later, is engaged with a stud pin 17 provided on the panel 12. Is supported by the inside of the panel 12. On the other hand, an electron gun 21 for emitting three electron beams 20B, 20G, and 20R is provided in the neck 19 of the funnel 13. The three electron beams 20B, 20G, and 20R emitted from the electron gun 21 are deflected by a deflection yoke 23 mounted outside the funnel 13, and the phosphor screen 14 is horizontally and vertically scanned through the shadow mask 15. As a result, a structure for displaying a color image is formed.

As shown in FIG. 2, the shadow mask 15 has an effective surface 25 facing the phosphor screen provided on the inner surface of the panel, which is flattened in correspondence with the inner surface of the effective portion of the panel. 25, a large number of electron beam passage holes 26 are provided.
A substantially rectangular mask body 28 having a plate thickness of about 0.1 to 0.3 mm formed by bending a mask body 7 and a substantially rectangular mask frame 29 attached to the skirt portion 27 of the mask body 25 Consists of

In particular, in this embodiment, the attachment of the mask frame 29 to the mask body 25 is performed as shown in FIG.
(A) shows the short axis (y-axis) end of the mask main body 28, and (b) shows the long axis (x-axis) end thereof. Are provided with two cut grooves 31, and the two cut grooves 31 form a tongue piece 32 on the short axis and the long axis. Then, the tongue piece 32, that is, the cut groove 31,
Two points indicated by crosses near the edges of the skirt 27 opposite the short axis end and the long axis end are fixed points 3 with the mask frame 29.
3 and the mask frame 29 on the tongue piece 32
It does not have a fixed point.

Further, in this embodiment, as shown in FIG. 4, the structure of the mask frame attaching portion is such that the interval between the fixing points 33 is A, the length of the cut groove 31 is B, and the cut groove 31 is fixed to the cut groove 31. When the distance from the point 33 is C, the width of the skirt portion 27 at the cut groove 31 is D, and the effective diagonal diameter of the shadow mask is RD, D is at least 3% of RD, that is, D ≧ (3/100) × RD B is 40% or more of D, that is, B ≧ (40/100) × DC ≦ (１ ／) × B A ≧ (2/3) × D and A ≦ (1 / 5) × RD.

The cut groove 34 on the long axis between the pair of cut grooves 31 shown in FIG. 3B is formed by pressing a flat plate-shaped shadow mask manufactured by a photo-etching method into a mask body. It is a notch for positioning at the time.

The distance A between the fixed points 33, the length B of the cut groove 31, the distance C between the cut groove 31 and the fixed point 33, the width D of the skirt 27 at the portion where the cut groove 31 is formed, and the diagonal of the shadow mask When the effective diameter RD is shown for a color picture tube having an aspect ratio of the effective portion of the panel of 16: 9 and a diagonal size of 76 cm, A = 30.6 mm B = 13.5 mm C = 6.0 mm D = 30.0 mm RD = 629.0 mm, and the width D of the skirt portion at the cut groove forming portion is (3/100) × RD = (3/100) × 718.6 = 21.6 mm, which is 3% or more of RD. ing.

The length B of the cut groove is (40/100) × D = (40/100) × 30.0 = 12.0 mm, which is 40% or more of D.

The interval A between the fixed points is And 以上 or more of D, and (５) × RD = (５) × 629.0 = 125.8 mm, which is 以下 or less of RD.

The distance C between the cut groove and the fixed point is And B is 以下 or less of B.

When the shadow mask 15 is configured as described above, the following effects can be obtained.

(A) Compared with the conventional shadow mask in which the mask frame is attached to the tongue piece (see FIG. 7), the mask frame 29 is attached with the high strength part near the cut groove 31 as a fixed point, so that the mask frame The displacement of the mask body can be reduced.

(B) The mask body 28 is pulled by the thermal expansion of the mask frame 29, and the force perpendicular to the skirt portion 27 and the distance between the fixed points 33 are increased at the fixed point 33 of the mask body 28 with the mask frame 29. Even if a horizontal force is applied, the cut groove 31 is interposed between the two fixing points 33, so that the fixing point 33 and its vicinity are only partially deformed in the resultant direction of the horizontal and vertical forces. And
The effect of the tensile force by the mask frame 29 on the mask body 28 can be reduced. That is, as compared with the conventional shadow mask (see FIG. 7B) attached to a position near the open edge of the tongue piece, the mask body when the fixed point 33 and its vicinity are pulled by the mask frame 29. 28 can be reduced.

(C) Compared with a conventional shadow mask (see FIG. 7) in which a mask frame is attached to a tongue piece, the interval between fixed points can be increased, and a mask centered on an axis perpendicular to the skirt portion 27 is provided. The rotation suppressing force of the mask body with respect to the frame can be increased, and the displacement of the shadow mask 15 with respect to the panel 14 can be reduced.

Next, different shapes of the cut grooves of the mask body will be described. FIG. 5 (a) shows a total of four cut grooves 31 symmetrically provided on both sides of the short axis or long axis of the mask body, and a short axis end or length near the outer cut groove 31 is provided. Two points indicated by crosses in the vicinity of the edge of the skirt portion 27 on the opposite side of the shaft end are fixed points 33 to the mask frame. FIG. 5B shows two cut grooves 31 symmetrically inclined with respect to the edge of the skirt portion 27 on both sides of the short axis or long axis of the mask body, and the cut grooves 31 are provided. Two points indicated by crosses near the edge of the skirt portion 27 on the opposite side of the short axis end or the long axis end are fixed points 33 to the mask frame. Even with this configuration,
A shadow mask having the same effect as the above embodiment can be formed.

FIG. 5C shows one cut groove 31 having a substantially rectangular shape on the short axis or long axis of the mask body.
FIG. 5D shows a single trapezoidal cut groove 31, FIG.
(E) is provided with one triangular cut groove 31, and two points indicated by crosses near the edge of the skirt portion 27 on the opposite side of the short axis end or long axis end near each cut groove 31. This is a fixed point 33 to the mask frame. Even with such a configuration, a shadow mask having the same effect as the above embodiment can be obtained.

In the above embodiment, the color picture tube in which the effective portion of the panel is flattened and the effective surface of the mask body of the shadow mask is flattened corresponding to the flattening of the panel has been described. However, the present invention can also be applied to a shadow mask for a color picture tube in which the outer surface of the effective portion of the panel has a relatively large curvature.

[0040]

When the shadow mask is configured as described above, the displacement of the shadow mask with respect to the panel can be reduced. Also, during the manufacturing process of the color picture tube or the operation of the color picture tube, the deformation of the mask body caused by the mask body being pulled by the thermal expansion of the mask frame can be reduced,
It can be a color picture tube that does not easily deteriorate color purity, and in order to improve visibility in particular, the effective surface is flattened corresponding to a panel whose outer surface is a flat surface or a curved surface with a slight curvature. When applied to a color picture tube having a shadow mask, a great effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a color picture tube according to an embodiment of the present invention.

FIG. 2A is a plan view showing a configuration of a shadow mask of the color picture tube, and FIG. 2B is a sectional view thereof.

FIG. 3A is a view showing a mounting structure of a mask frame to a mask main body near a short axis of the shadow mask, and FIG. 3B is a mounting structure of a mask frame to a mask main body near a long axis. FIG.

FIG. 4 is a view for explaining dimensions of a configuration of a mask frame attaching portion of the mask main body.

FIGS. 5 (a) to 5 (e) are views showing configurations different from the mask frame mounting portion of the mask main body.

FIG. 6A is a perspective view showing a configuration of a shadow mask of a conventional color picture tube, and FIG. 6B is a sectional view thereof.

FIG. 7A is a view showing a mounting structure of a mask frame to a mask body of a conventional shadow mask, and FIG.
(B) is a figure which shows the attachment structure of the mask frame with respect to the mask main body with a wide skirt part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Effective part 12 ... Panel 14 ... Phosphor screen 15 ... Shadow mask 25 ... Effective surface 26 ... Electron beam passage hole 27 ... Skirt part 28 ... Mask main body 29 ... Mask frame 31 ... Cut groove 33 ... Fixed point

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Murai 1-9-2 Harara-cho, Fukaya-shi, Saitama Pref. Inside the Toshiba Fukaya Plant (72) Inventor Masayo Inoue 1-9-1, Harara-cho, Fukaya-shi, Saitama No. 2 F-term in Toshiba Fukaya Plant (reference) 5C031 EE04 EE11

Claims (6)

[Claims] 1. A substantially rectangular shadow mask is disposed opposite a phosphor screen provided on an inner surface of an effective portion of a substantially rectangular panel, and the shadow mask includes a large number of electron beam passage holes. A substantially rectangular mask body in which a skirt is bent and formed on an outer periphery of an effective surface facing the phosphor screen, and a plurality of cut grooves are provided in the skirt; and a cut in the skirt. In a color picture tube comprising a mask frame attached to the mask body with the vicinity of the groove as a fixed point, the cut groove has a length of at least 3% of the diagonal effective diameter of the shadow mask near the short axis of the mask body. The cut frame has no fixed point with the mask frame on the short axis end side, and the mask frame is located near the edge of the skirt portion on the opposite side of the short axis end. It has a fixed point of the one gap between the fixed point and the cut grooves of the length of the notches
/ 2 or less. 2. One or at least two cut grooves are provided on the short axis of the mask body with the short axis of the mask body interposed therebetween, and the mask frame is attached to these cut grooves at two fixed points, 2. The color picture tube according to claim 1, wherein the distance between the two fixed points is at least 2/3 of the width of the skirt portion and at most 1/5 of the minor axis diameter of the effective surface of the mask body. 3. A substantially rectangular shadow mask is disposed facing a phosphor screen provided on an inner surface of an effective portion of the substantially rectangular panel, and the shadow mask is formed with a large number of electron beam passage holes. A substantially rectangular mask body in which a skirt is bent and formed on an outer periphery of an effective surface facing the phosphor screen, and a plurality of cut grooves are provided in the skirt; and a cut in the skirt. In a color picture tube comprising a mask frame attached to the mask body with the vicinity of the groove as a fixed point, the cut groove has a length near the major axis of the mask body of 3% or more of a diagonal effective diameter of the shadow mask. The cutout groove has no fixed point with the mask frame on the long axis end side, and the mask frame is located near the edge of the skirt portion on the opposite side of the long axis end. It has a fixed point of the one gap between the fixed point and the cut grooves of the length of the notches
/ 2 or less. 4. One or at least two cut grooves are provided on the long axis of the mask body with the long axis of the mask body interposed therebetween, and the mask frame is attached to these cut grooves at two fixed points; 4. The color picture tube according to claim 3, wherein the distance between the two fixed points is not less than 2/3 of the width of the skirt portion and not more than 1/5 of the minor axis diameter of the effective surface of the mask body. 5. The length of the cut groove is 40 times the width of the skirt.
%. The color picture tube according to any one of claims 1 to 4, wherein 6. A color picture tube according to claim 1, wherein the outer surface of the effective portion of the panel is a flat surface or a flattened curved surface having a slight curvature.