JP3466760B2 - Color picture tube - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask holding means for a color picture tube, and more particularly to a color picture tube having a shadow mask which is held by being applied with tension.

[0002]

2. Description of the Related Art A color picture tube has a panel having a fluorescent surface formed on its inner surface and an envelope made of a funnel connected to the panel. The fluorescent surface formed on the inner surface of the panel is red.
It is composed of a plurality of phosphor layers emitting green and blue respectively, and an electron gun that emits a plurality of electron beams corresponding to the emission colors is arranged at the neck portion of the funnel. Further, a shadow mask structure having a color selection function is arranged inside the panel between the electron gun and the fluorescent screen, and an image is reproduced by deflecting and scanning the electron beam in the horizontal and vertical directions.

In recent years, there has been an increasing demand for the flatness of the screen of a color picture tube from the viewpoint of viewability.
Further, color picture tubes used for computer displays and the like are required to have higher resolution. In order to increase the resolution of the color picture tube, it is necessary to reduce the aperture pitch of the shadow mask to achieve high definition, but since the apertures of the shadow mask are opened by etching, in order to achieve high definition. It is better that the mask material is thinner. On the other hand, from the viewpoint of mechanical strength of the mask, it is desired that the mask has a large plate thickness, and there are contradictory requirements for the plate thickness of the mask material.

In view of the above, a method has been proposed in which tension is applied to a flat mask having a relatively thin plate to hold it on the mask frame. This is for fixing and holding the peripheral portion to the mask frame in a state in which tension is applied to a flat shadow mask body having a large number of holes formed therein, and various methods of tension holding have been proposed. ing.

The first method has a structure as shown in FIG. 5 (a). This color picture tube has a panel 2 having a phosphor screen 1 formed on the inner surface thereof and a funnel 3 connected to the panel 2. The fluorescent surface 1 formed on the inner surface of the panel is composed of a plurality of fluorescent layers that emit red, green, and blue respectively, and the neck portion 4 of the funnel 3 corresponds to the emission color. An electron gun 5 that emits a plurality of electron beams is arranged. Further, the shadow mask 6 having a color selecting function has its upper and lower sides parallel to the horizontal (X axis) fixed to the frame 7, and the holder 8 fixed to the frame 7.
Is fitted to a stud pin (not shown) embedded in the side wall of the panel 2 to be disposed inside the panel 2 between the electron gun 5 and the fluorescent screen 1.

The holder 8 is made of a bimetal in which metals having different coefficients of thermal expansion are combined, and the heat of the shadow mask 6 caused by the electron beam bombardment is applied to the frame 7.
When it is transmitted through the holder 8, as shown in FIG.
Is deformed, and the shadow mask 6 is pushed out toward the phosphor screen 1 side. By moving the shadow mask 6 in this manner, the hole positions before and after the thermal expansion are corrected so as to be on the electron beam orbit, and the deterioration of the color purity is suppressed.

The second method, as shown in FIG. 6, is to fix the shadow mask 6 to which the stress σ is applied to the frame 7, and the distortion due to the stress σ indicated by the arrow in advance is applied to the shadow mask 6 at room temperature. By canceling out the dimensional variation of the shadow mask 6 due to thermal expansion and the variation of the strain amount due to the variation of the stress acting on the shadow mask 6, the dimensional variation of the shadow mask due to the temperature rise is compensated. This is to prevent the deterioration of image quality.

[0008]

However, in the method of using a holder made of bimetal as shown in FIG. 5, it takes a certain amount of time for heat to be transferred to the bimetal and to be thermally expanded, and until the bimetal is thermally expanded. There is a problem that the deterioration of color purity is not corrected during the time of.

On the other hand, ordinary iron materials and alloys used for shadow masks have temperature dependence of both thermal expansion coefficient and elastic coefficient, and in the case of the method shown in FIG. 6, the operation of the color picture tube. It is not possible to keep the amount of strain constant over the entire temperature range over time. Further, if the coefficient of thermal expansion and the coefficient of elasticity are both small with respect to temperature, it will be a special metal, and there will be a problem that the cost of the color picture tube will increase.

In view of the above problems, the present invention is capable of responsively preventing color purity deterioration due to temperature rise of the shadow mask without being affected by the temperature dependence of the shadow mask material. Intended to provide a tube.

[0011]

The present invention has been made in order to solve the above problems, and a panel having a phosphor screen formed on the inner surface thereof, a first axis and a second axis orthogonal to the first axis are provided.
A shadow mask for selecting the color of the electron beam emitted from the electron gun and projecting it onto the phosphors of the respective colors on the phosphor screen. A frame having a pair of mask fixing parts whose sides parallel to the first axis are fixed, and the shadow mask is fixed in a state where tension in the second axial direction is applied, and a fitting part thereof. In a color picture tube including a holder that supports the frame by fitting a support pin provided in the panel to the support panel, a support member is fixed between opposite end portions of the pair of mask fixing portions. Is
The holder is provided substantially at the center in the longitudinal direction of the support member, and the center portion of the support member is located closer to the phosphor screen than both end portions thereof is a color picture tube.

Further, the supporting member is characterized in that it is formed by a plate-like elastic body which is convexly curved toward the phosphor screen side. Further, the mask fixing portion is provided with a holder including a fitting portion into which the support pin on the inner surface of the panel is fitted, a fixing portion fixed to the mask fixing portion, and an elastic portion between the fitting portion and the fixing portion. It is characterized by being.

[0013]

According to the above-described structure, the shadow mask is held in a state in which tension is applied in one direction. However, when the shadow mask thermally expands due to electron beam bombardment, tension is applied to the shadow mask. The elastic force applied to the frame to apply it increases the distance between the mask fixing portions. Since the support member is fixed between the mask fixing portions and the holder is fixed in the center thereof, the mask fixing portion side which is both ends of the supporting member and the holder are provided due to the increase in the distance between the mask fixing portions. The distance in the tube axial direction from the center part is smaller. At this time, since the holder fixed to the support member is fitted to the support pin inside the panel, it does not move in the tube axis direction. Therefore, the expansion of the distance between the mask fixing portions due to the thermal expansion is
The mask fixing portion is moved to the phosphor screen side along the tube axis direction.

Generally, when the aperture of the shadow mask moves in a direction away from the tube axis due to thermal expansion, the aperture is positioned on a predetermined electron beam orbit by combining movement toward the phosphor screen side. It is possible to correct the deterioration of color purity by moving the shadow mask. Also in the present invention, it is possible to correct the color purity deterioration by moving the shadow mask as described above, and the thermal expansion of the shadow mask increases the distance between the mask fixing portions, and moves toward the phosphor screen side in relation to the holder position. Immediately leading to the movement of the mask, the responsiveness is improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the overall structure of a color picture tube according to the present invention, and particularly, schematically shows the arrangement state of a shadow mask structure inside a color picture tube. The entire structure of the color picture tube according to the present invention is the same as that shown in FIG. 5 of the related art except for a frame and a holder for holding a shadow mask. It has an envelope composed of the funnel 3 connected to the. The fluorescent surface 1 on the inner surface of the panel 2 is red,
An electron gun 5 which is composed of a plurality of phosphor layers which emits green and blue respectively, and which emits a plurality of electron beams corresponding to the emission colors is arranged in the neck portion 4 of the funnel 3. Further, inside the panel 2 between the electron gun 5 and the fluorescent screen 1, a shadow mask 6 having a color selecting function is arranged via a frame 10 and holders 15 and 16.

As shown in FIG. 2, the frame 10 includes a pair of mask fixing portions 11 and 12 to which the sides of the shadow mask 6 parallel to the X axis are fixed, and opposite end portions of the mask fixing portions 11 and 12. The support members 13 and 14 are provided between the two. The support members 13 and 14 are formed of a plate-shaped elastic body that is convexly curved toward the fluorescent screen side. Further, the holder 15 is provided at the center of the supporting members 13 and 14 in the longitudinal direction, but since the supporting members 13 and 14 are curved, the central portion 18a of the supporting members 13 and 14 has both ends 1 thereof.
It is located closer to the phosphor screen than 8b. Further, the mask fixing portions 11 and 12 are also provided with a holder 16. The holder 16 is a fixing portion fixed to the fitting portion 16a fitted to the support pin on the inner surface of the panel and the mask fixing portions 11 and 12. 16b, fitting portion 16a, and fixing portion 16b
The elastic portions 16c are provided between the fixing portions 16a and the mask fixing portions 11 and 12, and the fixing portions 16a move toward the fluorescent screen side when the distance between the fitting portions 16a and the mask fixing portions 11 and 12 becomes small. In addition, the holder 15 provided on the support members 13 and 14 described above.
Need only have a structure capable of supporting the frame 16 inside the panel, and does not need to have the elastic movement function of the holder 16 provided in the mask fixing portions 11 and 12.

Next, the operation of the present invention will be described with reference to the drawings. As shown in FIG. 3A, consider a state in which an electron beam impinges on a shadow mask held under tension. If the shadow mask does not thermally expand due to the energy of the electron beam, it remains in the state of FIG. 3A, and the electron beam is landed at a predetermined position P ₁ on the phosphor screen, but when the shadow mask thermally expands, The elastic force applied to the frame to apply tension to the shadow mask increases the distance between the mask fixing portions 11 and 12.
A curved support member 1 is provided between the mask fixing portions 11 and 12.
3, 14 are fixed, and the holder 15 is attached to the central portion 18a.
Since the mask fixing portions 11 and 12 are fixed, the curvature of the supporting members 13 and 14 is relaxed due to the increase in the distance between the mask fixing portions 11 and 12, and the tube axial direction distance between the central portion 18a and both end portions 18b is changed from Z _1. It changes so as to decrease to Z ₂ . At this time, since the holder 15 fixed to the support members 13 and 14 is fitted to the support pin inside the panel, it does not move in the tube axis direction. Therefore, the expansion of the distance between the mask fixing portions due to the thermal expansion moves the mask fixing portion toward the phosphor screen side along the tube axis direction by the distance (Z ₁ -Z ₂ ).

When the distance between the mask fixing portions 11 and 12 increases, a compressive force is applied to the holder 16 and the fitting portion 16
The distance between a and the fixed portion 16b decreases from Y ₁ to Y ₂ , and the fixed portion 16b moves to the phosphor screen side. Therefore, without affecting the movement of the shadow mask,
The top and bottom of the frame can be held stably.

Generally, when the aperture moves away from the tube axis due to thermal expansion, that is, when the shadow mask is in the state of 6a in FIG. Land on position P ₂ and the color purity deteriorates. Therefore, by moving the shadow mask to the state of 6b, it is possible to position the aperture on the electron beam trajectory shown by the broken line before the predetermined thermal expansion, and the electron beam can be landed at the predetermined position P _1. It is possible to correct the color purity deterioration. Also in the present invention, it is possible to correct the color purity deterioration by moving the mask as described above, the thermal expansion of the mask increases the distance between the mask fixing portions, and the mask to the phosphor screen side in relation to the holder position. Immediately connected to the movement, the responsiveness becomes good.

The shadow mask as described above can be manufactured as follows. That is, FIG.
As shown in (a), the mask fixing portion 1 of the frame 10
A supporting member 1 made of an elastic body by applying a compressive force F to the members 1 and 12.
1 and 12 are greatly curved in a state that they are convex toward the phosphor screen side,
In this state, the shadow mask 6 is attached to the mask fixing portions 11 and 12
Compressive force F applied to the mask fixing part after welding and fixing to
To cancel. By doing so, the tension T can be applied to the shadow mask 6 by the elastic force of the support members 11 and 12, as shown in FIG.

As described above, by using the curved elastic body as the support member, not only a predetermined tension can be applied to the shadow mask by the elastic force, but also the change of the curvature degree is changed in the axial direction of the frame. It becomes possible to easily convert it into movement.

Although the supporting member is formed of a plate-like elastic body in the above-described example, the frame structure for applying tension to the shadow mask is not limited to the above structure, and the distance between the tension applying means and the mask fixing portion is not limited to the above structure. The mechanism for converting the expansion of the above into a movement in the tube axis direction may be separately configured.

[0023]

As described above, according to the present invention,
It is possible to correct the deterioration of color purity without causing a time delay after the shadow mask causes thermal expansion. Further, even if a shadow mask material having a relatively large coefficient of thermal expansion is used, the frame can be moved in accordance with the coefficient of thermal expansion, so that it is possible to appropriately correct the color purity deterioration regardless of the material.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing the structure of a color picture tube according to the present invention.

FIG. 2 is a schematic perspective view showing a frame structure of the color picture tube of FIG.

FIG. 3 is a diagram for explaining the operation of the present invention, in which (a) shows a state before thermal expansion of the shadow mask, and (b).
Indicates the state when the thermal expansion of the shadow mask occurs.

FIG. 4 is a diagram schematically illustrating a method for manufacturing a mask structure for a color picture tube according to the present invention, in which (a) shows a frame state before welding and fixing the shadow mask, and (b) shows welding the shadow mask to the frame. It is a figure which shows the state of tension when fixed.

5A and 5B are schematic diagrams showing a configuration of a conventional color picture tube, FIG. 5A is a sectional view, and FIG. 5B is a schematic diagram for explaining the operation of a bimetal type holder.

FIG. 6 is a diagram showing another example of a mask structure of a conventional color picture tube.

[Explanation of symbols]

6 ... Shadow mask 10 ... Frame 11, 12 ... Mask fixing part 13, 14 ... Support member 15, 16 ... Holder 18a ... central part of support member 18b ... Both ends of the supporting member

Claims (3)

(57) [Claims] 1. An electron gun comprising: a panel having a phosphor screen formed on its inner surface; and a substantially rectangular flat plate member having a first axis and a second axis orthogonal to the first axis. A shadow mask for color-selecting the emitted electron beams to impinge on each color phosphor on the phosphor screen, and a pair of mask fixing portions to which sides of the shadow mask parallel to the first axis are fixed. The frame is fixed to the shadow mask in a state where the tension in the second axial direction is applied, and the supporting pin provided in the panel is fitted to the fitting portion to support the frame. In a color picture tube including a holder, a support member is fixed between the opposite end portions of the pair of mask fixing portions, and the holder is provided substantially at the center in the longitudinal direction of the support member. , The central part of the supporting part Color picture tube, characterized in that located in the phosphor screen side from both ends thereof. 2. The color picture tube according to claim 1, wherein the support member is formed of a plate-shaped elastic body that is convexly curved toward the fluorescent screen side. 3. The mask fixing portion includes a fitting portion into which a support pin on the inner surface of the panel is fitted, a fixing portion fixed to the mask fixing portion, and an elastic portion between the fitting portion and the fixing portion. 3. A holder is provided, wherein the holder is provided.
A color picture tube according to any one of 1.