JP2002157964A - Shadow mask for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shadow mask for a cathode-ray tube causing no inconvenience such as the deterioration of an image by irregular reflection of an electron beam even when a pseudo bridge is formed in a slot tension type shadow mask. SOLUTION: For attaining the purpose, in the slot tension type shadow mask for the cathode-ray tube, this shadow mask for the cathode-ray tube is characterized in that the pseudo bridge is formed in a slot part, and a lay is formed in the Y axis direction in the pseudo bridge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a tension type shadow mask for a cathode ray tube.

[0002]

2. Description of the Related Art Conventionally, there have been press type and tension type shadow masks for cathode ray tubes.
The need for a one-dimensional tension type has been increasing due to the need to respond to the recent flattening of cathode ray tubes.

[0003] In such a one-dimensional tension type shadow mask, a metal thin film is subjected to an etching process, and a steel plate formed of vertical slit holes formed in a predetermined shape is given a relatively high tension. Aperture grill type, which is used by attaching it vertically to a steel frame in a state, and a steel plate with rectangular holes (slots) similar to the press type, which is attached to a steel frame vertically using a relatively low tension. Slot tension type.

[0004] However, the slot tension type shadow mask has a problem that the steel plate expands due to heat during use, and there is a possibility that mislanding may occur at the outer peripheral portion in the X-axis direction. This is because, in the X-axis direction where no tension is applied, the bridges above and below each slot expand due to heat, and this expansion accumulates and the position in the X-axis direction is greatly shifted. For this reason, a material having a low coefficient of thermal expansion is used, but since the material itself is expensive, improvement in structure has been desired.

As a method of solving such a problem in terms of the structure, a method has been proposed in which the number of bridges is reduced, that is, each slot is a slot elongated in the Y-axis direction. However, when the number of bridges is reduced in this way, the position of the bridge is caught by the naked eye as a line on the screen when used by being attached to a cathode ray tube, and this causes a problem that it causes visual impairment.

In order to solve such a problem, a technique called a pseudo bridge has been proposed. In this method, for example, as shown in FIG. 4, a pseudo bridge 4 composed of convex portions 2 and 2 protruding from both sides and a gap 3 therebetween is provided at a certain interval in the Y-axis direction of each slot 1, By making the passing amount of the electron beam through the pseudo bridge 4 approximately equal to that of the regular bridge 5, shadows of the bridge are formed at intervals of 0.5 to 1.0 mm as in a normal slot type cathode-ray tube, and visual impairment is caused. That is to prevent. on the other hand,
Since the pseudo bridge 4 has the gap 3, even when heat is applied, the pseudo bridge 4 does not expand in this portion in the X-axis direction.
The same effect as when a long slot is provided in the Y-axis direction can be obtained.

However, when such a pseudo bridge is provided, especially when the pseudo bridge is formed on the outer peripheral side in the Y-axis direction, irregular reflection occurs at the convex portion 2 of the pseudo bridge, which adversely affects the image on the CRT. Such a problem may occur. This will be described with reference to FIG.

FIG. 3 (a) shows a slit having a pseudo bridge 4 formed by two openings 6 and two projections 2, 2 formed therebetween and a gap 3 formed therebetween. And a plan view from the side opposite to the electron gun, that is, from the screen side. (B) is a cross-sectional view taken along the line AA ′ of (a). This slit is
When the shadow mask is located at a relatively outer peripheral portion in the Y-axis direction, the incident angle α of the electron beam 7 has a relatively large value. When the incident angle α is relatively large, the electron beam 7 incident from the vicinity of the convex portion 2 of the opening 6 on the mask center side is shielded by the convex portion 2 of the pseudo bridge 4 as shown in FIG. Will be. In this case, there is a problem that the shielded electron beam 7 is irregularly reflected, which adversely affects the cathode ray tube.

[0009]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in view of the above problem. In a slot tension type shadow mask, even if a pseudo bridge is formed, the color due to irregular reflection of an electron beam is reduced. An object of the present invention is to provide a shadow mask for a cathode ray tube which does not deteriorate in purity.

[0010]

In order to achieve the above object, according to the present invention, in a shadow mask for a CRT of a slot tension type, a pseudo bridge is formed in a slot portion. Provided is a shadow mask for a cathode ray tube, characterized in that a crossing in the Y-axis direction is formed in the pseudo bridge.

In the present invention, since the quasi-bridge is formed with an offset in the Y-axis direction, the quasi-bridge has a quasi-electron beam even on the outer peripheral side in the Y-axis direction where the incident angle of the electron beam is relatively large. Irradiation to the convex portion of the bridge does not cause irregular reflection. Therefore, it is possible to prevent the color purity from being deteriorated due to the irregular reflection of the electron beam.

Further, in the invention described in the first aspect, as described in the second aspect, the width of the outer peripheral side edge is larger than the width of the mask center side end portion in the gap on the electron gun side surface of the pseudo bridge. It is preferable that the width of the portion is widened at a rate of 10% to 100%.

In the case where a gap is formed in the pseudo bridge in which the crossing is formed in the Y-axis direction, the gap is formed on the side where the crossing is formed, that is, on the mask center side, because the thickness of the steel sheet is reduced due to the crossing. Etching for forming is easy to proceed, and on the other hand, the outer peripheral side is less affected by crossing, so that the thickness of the steel sheet is large, and it is relatively difficult to form voids. For this reason, when etching is performed in the same manner, there is a possibility that a problem that a gap on the outer peripheral side is not formed may occur. Therefore, the width on the outer peripheral side is 20% to the width on the mask center side in the gap on the electron gun side surface of the pseudo bridge.
The above-mentioned disadvantages are prevented by forming the film wide at a rate of 100%.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The shadow mask for a cathode ray tube according to the present invention will be described in detail below. The present invention is applied to a slot tension type shadow mask for a cathode ray tube. As shown in FIG. 5, the slot tension type shadow mask for a cathode ray tube is composed of a cathode ray passing portion 10 composed of a number of fine rectangular holes (slots) and a skirt portion 11. As shown in FIG. 6, such a slot tension type shadow mask for a cathode ray tube is welded to a rectangular frame 12 made of steel or the like in a tension state, and unnecessary portions are cut off and fixed at a predetermined position inside the panel surface of the cathode ray tube. Is done. The cathode ray emitted from the electron gun of the cathode ray tube passes through the cathode ray passage portion of the shadow mask to cause the phosphor on the entire panel to emit light, whereby an image is displayed on the panel as an aggregate of fine light spots.

The present invention is characterized in that the pseudo bridge provided in such a slot of the shadow mask is formed with an offset in the Y-axis direction. Here, the pseudo bridge is provided at a constant interval in the Y-axis direction of each slot as described above, and includes two convex portions protruding from both sides and a gap provided therebetween. It is. Forming a cross-over in the Y-axis direction on the pseudo bridge means that a cross-over in the Y-axis direction is formed on the convex portion of the pseudo bridge.

Here, the Y-axis direction is the longitudinal direction of the slot and indicates the direction in which tension is applied. In the present invention, the X-axis direction is
The direction on the shadow mask plane is perpendicular to the Y axis, and the Z axis direction is a direction perpendicular to the shadow mask plane.

Hereinafter, the shadow mask of the present invention will be described.
This will be described with reference to the drawings. FIG. 1A is a plan view of a slot portion of the shadow mask of the present invention as viewed from the screen side, and FIG. 1B is a cross-sectional view taken along the line BB ′. In the example of this figure, an example is described in which a pseudo bridge 4 composed of two convex portions 2 and 2 and a gap 3 formed therebetween is formed between two opening portions 6. According to the present invention, as described above, the projection 2 of the pseudo bridge 4
It has a feature in that a crosswise stitch in the axial direction is formed.

In the present invention, the convex portion 2 of the pseudo bridge 4
Forming a cross-over in the Y-axis direction means that the outer etching portion 8 on the outer peripheral side in the Y-axis direction of the convex portion 2 on the screen side (opposite side to the electron gun) surface and the inner etching portion 9 on the Y-axis direction mask center side. The width, that is, the relationship of the length in the Y-axis direction, means that the inner etching portion 9 is formed to be longer. Here, the outer etched portion 8 indicates a portion between the Y-axis direction outer peripheral end a of the convex portion 2 and the Y-axis outer peripheral end b of the screen-side steel plate surface 10 in the convex portion 2. On the other hand, the inner etched portion 9 indicates a portion between the Y-axis direction mask center side end c of the projection 2 and the Y-axis direction mask center side end d of the screen-side steel plate surface 10 in the projection 2.

As described above, the convex portion 2 of the pseudo bridge 4
By forming the offset in the axial direction, as shown in FIG. 1B, the electron beam can pass through the outer peripheral portion in the Y-axis direction where the incident angle α of the electron beam 7 is relatively large without being shielded. Therefore, irregular reflection does not occur, and the problem of deterioration of color purity does not occur.

In the present invention, in general, the pseudo bridge closer to the outer peripheral portion in the Y-axis direction is formed so that the difference between the width of the inner etched portion and the width of the outer etched portion becomes larger. No axial offset is formed.

When the cross-section in the Y-axis direction is formed in the convex portion of the pseudo bridge as described above, the outer etching portion 8 and the inner etching portion 9 of the convex portion 2 are formed as shown in FIG.
The thickness of the inner etched portion 9 is much smaller than that of the outer etched portion 8. Therefore, when the void 3 is formed by etching in a portion having such a shape, the inner etched portion 9 can easily penetrate to form the void 3, but the outer etched portion 8 hardly penetrates. If it cannot penetrate, there may be a problem that the effect as a pseudo bridge cannot be obtained.

In the present invention, in order to avoid such a problem, in the pseudo bridge in which the crossing in the Y-axis direction is formed, the width of the gap on the surface on the electron gun side relative to the width of the end on the mask center side is determined. It is preferable to form the width of the outer peripheral end portion wide. Thereby, the etching amount of the outer etching portion 8 can be increased, and a problem that the void 3 does not penetrate when the gap 3 is formed in the outer etching portion 8 can be prevented.

FIG. 2 shows the surface of the steel plate on the electron gun side of the pseudo bridge 4 portion. The width e of the end of the gap 3 on the outer peripheral side in the Y-axis direction is larger than the width f of the end on the mask center side. This shows a large state.

In the present invention, the width of the outer peripheral end of the pseudo bridge is 10% to 100% wider than the width of the Y-axis direction mask center side end in the gap on the electron gun side surface. It is preferably formed, especially 20
It is preferably formed to be wide at a rate of up to 30%, especially 20 to 25%.

In this case, the shape of the gap 3 may be such that the width is linearly widened from the mask center side to the outer peripheral side as shown in FIG. If the width e of the outer peripheral end of the gap 3 in the Y-axis direction is finally formed to be wider than the width f of the end of the mask center side by the above-described ratio, the shape of the gap 3 therebetween is particularly limited. Not something.

The present invention is not limited to the above embodiment. The above embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and has the same effect. Within the technical scope of

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The shadow mask for a cathode ray tube according to the present invention will be specifically described below with reference to embodiments.

(Example 1: Offset of pseudo bridge in Y-axis direction) In a shadow mask for a cathode ray tube of 29 inches, the width of the inner etching portion 9 at a position where the incident angle α of the electron beam in the Y-axis direction is 35 °. (A) is set to 71 μm, and the width (B) of the outer etched portion 8 is set to 20 μm.
An offset in the Y-axis direction was formed (see FIG. 7). In addition, at the position where the incident angle α was 15 °, 25 °, and even 30 °, a shift in the Y-axis direction was formed. Table 1 below summarizes the width (A) of the inner etching portion 9 and the width (B) of the outer etching portion 8 at this time. The thickness of the steel sheet in this case was 100 μm.

[0029]

[Table 1]

The CRT using the shadow mask was of good quality without color purity deterioration due to irregular reflection of the electron beam.

(Embodiment 2: Surface Shape on the Side of Electron Gun in Gap of Pseudo Bridge) At the position where the incident angle α in the Y-axis direction is 35 °, when the width of the gap 3 is about 50 μm, FIG. As shown in the figure, the width e of the end of the gap 3 on the outer peripheral side in the Y-axis direction on the surface of the steel plate on the electron gun side is set to 100.
By setting the width to μm and the width f on the mask center side to 80 μm, the cut surface with few protrusions could be formed by giving an inclination.

[0032]

As described above, in the present invention, since the pseudo bridge is formed with a cross in the Y-axis direction,
Even at the outer peripheral portion in the Y-axis direction where the incident angle of the electron beam is relatively large, the electron beam does not irradiate the convex portion of the pseudo bridge and does not cause irregular reflection. Therefore, it is possible to prevent a problem such as disturbance of an image caused by irregular reflection of the electron beam.

[Brief description of the drawings]

FIG. 1 shows an example of a pseudo bridge in a shadow mask for a cathode ray tube of the present invention, wherein (a) is a plan view,
(B) is a sectional view taken along the line BB '.

FIG. 2 is a schematic plan view showing an electron gun side surface of a gap of a pseudo bridge in the shadow mask for a cathode ray tube of the present invention.

3A and 3B show an example of a pseudo bridge of a shadow mask for a cathode ray tube, wherein FIG. 3A is a plan view and FIG.
FIG. 4 is a cross-sectional view taken along the line -A ′.

FIG. 4 is a plan view for explaining a pseudo bridge.

FIG. 5 is a schematic plan view for explaining a slot tension type shadow mask.

FIG. 6 is a schematic perspective view showing an attached state of a slot tension type shadow mask.

FIGS. 7A and 7B are schematic views for explaining a cross-over in the Y-axis direction formed in the first embodiment, where FIG. 7A is a plan view and FIG.
It is a cross-sectional view.

FIG. 8 is a schematic plan view for explaining a second embodiment.

[Explanation of symbols]

 1 ... Slot 2 ... Protrusion 3 ... Void 4 ... Pseudo bridge 6 ... Opening

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Makita 1-1-1, Ichigaya-Kagacho, Shinjuku-ku, Tokyo F-term in Dai Nippon Printing Co., Ltd. (reference) 5C031 EE02 EF05 EF06 EF07 EF09

Claims (2)

[Claims] 1. A shadow mask for a CRT according to claim 1, wherein a pseudo bridge is formed in a slot portion, and a crossing in the Y-axis direction is formed in said pseudo bridge. 2. The width of an outer peripheral end portion of the pseudo bridge is 10% to 100% wider than a width of a mask center end portion in a gap on an electron gun side surface of the pseudo bridge. The shadow mask for a cathode ray tube according to claim 1, wherein