JPH044684B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a color picture tube, and in particular to a color picture tube of the shadow mask type, which is designed to reduce deviations in beam landing due to thermal deformation of a mask frame holding a shadow mask. The invention relates to color picture tubes.

[Technical background of the invention and its problems]

As is well known, the shadow mask structure used in a shadow mask type color picture tube consists of a shadow mask ₂₁ whose skirt portion is held by a mask frame 1, and a support structure (not shown), as shown in FIG. The mask frame 1 is the shadow mask 2
It is made of a thick iron plate and is formed into a substantially rectangular shape with an L-shaped cross section so that the strength is greater than that of ₁ .

In this way, in the shadow mask structure consisting of the shadow mask 2 ₁ and the mask frame 1 that holds it, the shadow mask 2 ₁ undergoes thermal deformation due to the impact of the electron beam at the beginning of the operation of the color picture tube, for example, as shown in 2 ₂ . When the electron beam expands, the relative position between the electron beam and the phosphor screen shifts, causing a beam landing shift, and a color shift phenomenon occurs in the color image reproduced on the phosphor screen.

Such displacement of the shadow mask 2 ₁ toward 2 ₂ due to so-called doming should be recovered in approximately a few minutes due to the heating of the mask frame 1 and the operation of the support structure made of bimetal and springs, but it is not completely recovered. does not recover.

The reason for this is that thermal deformation in the mask frame 1 as shown in Fig. 2 was conventionally thought to be an outward elongation in the horizontal axis XX direction and vertical axis Y-Y direction, but in reality the mask frame 1 When examining the thermal deformation of the mask frame 1, as shown in Fig. 3, the long side _1V of the mask frame 1 in the vertical axis Y-Y direction shows an outward displacement _FV as shown by the outer broken line. It was found that the short side 1 _H of is indicated by the displacement F _H in the inward direction, as shown by the inner dashed line. It has been found that stress is applied to the shadow mask ₂₁ in the direction of the horizontal axis XX due to this inward displacement _FH , and that the displaced position ₂₂ of the shadow mask ₂₁ shown in FIG. 1 cannot be recovered.

The factors that cause the inward displacement F _H to occur on the short side 1 _H are the difference in temperature distribution due to the impact of the electron beam in the horizontal axis XX and vertical axis Y-Y directions, and the short side 1 _H of the mask frame 1. It is related to the difference between the radius of curvature R _H of and the radius of curvature R _V of the long side 1 _V.

In other words, the temperature rise of the mask frame 1 depends on the shape and arrangement of the electron beam passage holes 2a (which are designed to have good heat conduction in the vertical direction).
Due to the difference in length between the long side 1 _V and the short side 1 _H , the vertical axis Y-Y direction is faster than the horizontal axis X-X direction _.
is thermally deformed in the displacement F _V direction. At this time, a rotational force is generated in the mask frame 1 around the corner 1c, and an inward displacement _FH is generated in the short side _1H .

This displacement F _H is curvature radius R _H of short side 1 _H is long side 1 _V
It can be easily inferred that the larger the radius of curvature R _V is, the larger it appears.

For example, in the case of a conventional 22-inch color picture tube,
The radius of curvature R _V of the long side 1 _V of the mask frame 1 is approximately
3500mmR, radius of curvature _R of short side _1H is approximately 15000mmR
The length l V in the direction parallel to the horizontal axis X-X of the part from the center of the long side 1 _V , that is, the position where the outer periphery of the long side intersects with the vertical axis Y-Y to the position excluding the corner _1c , is approximately 220 mm. , the shoulder drop d _V of the long side 1 V _in the vertical axis Y-Y direction due to the radius of curvature R _V from the position intersecting this vertical axis Y-Y to the position excluding corner 1c is d _V = R _V −√− _V ² − _V ² 6.92mm ……(1) The center of short side 1 _H , that is, the outer periphery of the short side is the horizontal axis X-X
The length l _H in the direction parallel to the vertical axis Y-Y from the point where it intersects to the point excluding corner 1c is approximately 165
mm, corner 1 from the position intersecting this horizontal axis
The shoulder drop d _H of the short side 1 H due to the radius of curvature R _H of the part up to the position excluding c is _{d H =} R _H −√− _H ² − _H ² 0.91mm ……(2), and the short side of the mask frame 1 is The outer periphery of the side _1H is almost a straight line, and the outer periphery of the long side _1V is formed into a curved surface with a relatively small radius of curvature. As is clear from this, first _, when the long side 1 _V is displaced outward due to the temperature rise, this displacement F _V causes the corner 1 c
A rotational moment is generated around , and the short side _1H is displaced inward ( _FH) .

[Purpose of the invention]

The present invention has been made in view of the above-mentioned problems, and provides a color image receiving system having a shadow mask structure with extremely little landing deviation by slightly changing the shape of the mask frame without complicating the manufacturing process or method. The purpose is to provide a tube.

[Summary of the invention]

That is, the present invention provides a color image receiving device that includes at least a shadow mask structure consisting of a shadow mask that is disposed at a predetermined distance from a phosphor screen formed on the inner surface of a panel, and a mask frame that holds the skirt portion of this shadow mask. In a pipe, the panel, shadow mask, and mask frame are approximately rectangular in shape with long sides perpendicular to the vertical axis and short sides perpendicular to the horizontal axis, and the position where the outer periphery of the long side of the mask frame intersects with the vertical axis. The length of the part in the direction parallel to the horizontal axis from to the position excluding the corner is l _V , the radius of curvature of the part from the position where it intersects with this vertical axis to the position excluding the corner is R _V , and the length of the long side due to this radius of curvature is The shoulder drop in the vertical direction is _dV , and the length in the direction parallel to the vertical axis from the position where the outer periphery of the short side of the mask frame intersects with the horizontal axis to the position excluding the corner is _lH , and this horizontal axis and The radius of curvature of the part from the intersection point to the point excluding the corner is R _H ,
The horizontal shoulder drop of the short side due to this radius of curvature is d _H
When R _H < R _V , d _V = A × l _V , d _H = B × l _H , where A and B satisfy 0.010 to 0.035. This is a color picture tube characterized by a shape that approximates the radius of curvature, especially when the radius of curvature is bent in multiple stages.

[Embodiments of the invention]

Next, one embodiment of the color picture tube of the present invention will be described with reference to FIGS. 4 and 5.

That is, the color picture tube has a red color on the inner surface of the panel 9.
A phosphor screen 10 on which phosphor layers of three colors of green and blue are regularly deposited in the vertical axis Y-Y direction is provided, and a shadow mask structure is provided opposite to this phosphor screen 10 at a predetermined distance. ing. The skirt portion of the shadow mask 12 ₁ of this shadow mask structure is held by the mask frame 11. This mask frame 11 has a first side 11 substantially perpendicular to the tube axis.
₁ , and a second side ₁₁₂ extending from the panel 9 side of this first side ₁₁₁ in the direction of the fluorescent screen 10.
₁₂ , the skirt portion of the shadow mask ₁₂₁ is welded and held at a plurality of welding points. and,
A support structure 13 is attached to this second side 11 ₂ to be engaged with a panel pin (not shown) of the panel 9. The panel 9, the shadow mask ₁₂₁ , and the mask frame 11 each have a substantially rectangular shape. Taking the mask frame 11 as an example, as shown in FIG. 11 _V , short side 11 _H in the direction perpendicular to the horizontal axis
The shadow mask ₁₂₁ , which has a substantially rectangular shape with .

The open end surface of the panel 9 is the funnel 1.
4, and this funnel 14 has a horizontal axis
A net 16 housing an electron gun 15 that emits three electron beams 17 arranged in a row in the -X direction is welded.

When such a color picture tube is driven, the three electron beams 17 emitted from the electron gun 15 impinge on each phosphor layer of the phosphor screen 10 through the electron beam passage hole 12a of the shadow mask ₁₂₁ , producing a color image. However, most of this electron beam 17 collides with the shadow mask 12 ₁ and heats the shadow mask 12 ₁ . Therefore, a so-called doming phenomenon occurs in which the shadow mask 12 ₁ is displaced to the position 12 ₂ at the beginning of the operation. The heat that displaces the shadow mask ₁₂₂ heats the long side _11V of the mask frame 11, so that an outward displacement _FV is generated on the long side _11V , and an inward displacement _FH is generated on the short side _11H . Acting is a conventional mask frame 11
However, in this embodiment, these displacements F _V ,
The mask frame 11 is characterized in that the outer peripheral shape of the mask frame 11 is shaped as follows so as to reduce _FH .

The present inventors conducted various experiments using the cut-and-try method, and obtained the following results.

That is, the axis x-x parallel to the horizontal axis X-X from the position where the outer periphery of the long side of the mask frame 11 intersects with the vertical axis Y-Y to the position excluding the corner 11c.
The length in the direction is l _V , the vertical drop of the long side 11 V due to the radius of curvature R _V from the position intersecting this vertical axis Y-Y to the position excluding the corner 11 _c is d _V , and the short side Vertical axis Y- of the part from the position where the outer circumference intersects with the horizontal axis X-X to the position excluding corner 11c
Let l _H be the length in the direction parallel to Y, and let d _H be the drop in the vertical direction of the long side 11 H due to the radius of curvature R _H from the point where it intersects with this horizontal axis _XX to the position excluding the corner 11c. In this case, when the following relationships exist: d _V 0.02l _V . . . (3) d _H 0.02l _H .

In other words, the outer circumference of the mask frame is R _V = d _V ² + l _V ² /2d _V ...(5) R _H = d _H ² +l _H ² /2d _V ...(6), so it is different from the color picture tube shown in the conventional example. In the case of a similar 22-inch color picture tube, d _V = 2.0mm, R _V 12100mmR, d _H = 1.65mm, R _H 8250mmR, and contrary to the conventional relationship of R _H ≫ R _V , the relationship of R _H ≪ R _V It becomes a relationship.

Further generalizing this value from experimental results, the displacement
The conditions for canceling the rotational moment due to F _V are (3),
In equation (4), d _V =A×l _V (7) d _H =B×l _H (8) holds true when A and B are in the range of 0.010 to 0.035. If the mask frame shape is configured according to the above conditions, the inward displacement F _H of the short side of the mask frame will not occur, and the thermal deformation of the shadow mask at the beginning of its operation described above can be recovered in a short time. I understand.

In the above embodiment, the outer periphery of the mask frame is described as having a curved shape, but it goes without saying that even if the mask frame is made into a multi-stage bent shape, the same effect can be obtained as long as the approximate shape satisfies the above-mentioned relationship. .

〔Effect of the invention〕

As described above, according to the present invention, it is possible to prevent undesired deformation of the long and short sides of the mask frame at the initial stage of operation of the color picture tube, thereby significantly reducing beam landing deviation due to thermal deformation of the shadow mask. The industrial value is extremely large.

[Brief explanation of drawings]

1 to 3 are diagrams showing a shadow mask structure consisting of a shadow mask and a mask frame used in a conventional color picture tube. FIG. 1 is an explanatory diagram showing thermal deformation of the shadow mask, and FIG. Explanatory rear view showing the shape, 3rd
The figure is an explanatory view showing the deformation of the long side and short side of the mask frame, FIGS. 4 and 5 are views showing an embodiment of the color picture tube of the present invention, and FIG. 4 is an explanatory sectional view. FIG. 5 is a rear view of the shadow mask structure. 1, 11...mask frame, 1 _V , 11 _V ...
Long side, 1 _H , 11 _H ...Short side, 1c, 11c...Corner, 2 ₁ , 2 ₂ , 12 ₁ , 12 ₂ ...Shadow mask, 2a, 12a...Electron beam passage hole, R _V
...Radius of curvature of the long side, R _H ...Radius of curvature of the short side.

Claims (1)

[Scope of Claims] 1. At least a shadow mask structure comprising a shadow mask disposed opposite to a phosphor screen formed on the inner surface of the panel at a predetermined distance, and a mask frame that holds the skirt portion of this shadow mask. In the color picture tube, the panel, the shadow mask, and the mask frame have a substantially rectangular shape with a long side perpendicular to the vertical axis and a short side perpendicular to the horizontal axis, and the outer periphery of the long side of the mask frame is The length in the direction parallel to the horizontal axis of the part from the position where it intersects with the vertical axis to the position excluding the corner is l _V , the radius of curvature of the part from the position where it intersects with this vertical axis to the position excluding the corner is R _V , this The shoulder drop in the vertical direction of the long side due to the radius of curvature is _dV , and the length in the direction parallel to the vertical axis from the position where the outer periphery of the short side of the mask frame intersects with the horizontal axis to the position excluding the corner is l _H , R _H is the radius of curvature of the part from the point where it intersects with this horizontal axis to a position excluding corners, and d _H is the shoulder drop in the horizontal direction of the short side due to this radius of curvature, then R _H < R _V , d _V = A × l _V , d _H =
A color picture tube characterized in that it has an outer peripheral shape satisfying B×l _H , where A and B satisfy 0.010 to 0.035. 2. The color picture tube according to claim 1, wherein the radius of curvature is an approximate shape when the mask frame is bent in multiple stages.