JPH0724195B2 - Color picture tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to a shadow mask type color picture tube, and more particularly to a shadow mask.

(Prior Art) Generally, in a shadow mask type color picture tube, a vacuum envelope is composed of a substantially rectangular panel, a funnel-shaped funnel and a neck. And red on the inside of the panel,
A phosphor screen composed of striped phosphor layers that emit green and blue respectively is formed, and three electron beams corresponding to red, green and blue are arranged on the neck in a line along the horizontal axis of the panel. A so-called in-line type electron gun for injecting In addition, at a position close to and facing the phosphor screen, a peripheral portion of the mask frame is supported and a large number of slit-shaped apertures are vertically arranged, and a shadow mask in which a large number of these vertical arrangements are horizontally arranged is elastic. It is supported via a support.

The three in-line electron beams are deflected by a deflection device outside the funnel, scan a rectangular area corresponding to the rectangular panel, and are color-selected through the apertures of the shadow mask to form stripes. It is designed to land on the phosphor layer and reproduce a color image.
That is, as shown in FIG. 4, a rectangular mask frame (7) equipped with a rectangular shadow mask (5) is
It is elastically supported in the panel (1) by four elastic supports (8).

The four elastic supports (8) are made of a metal spring piece (8a), one edge of which is fixed to the outer surface of the outer wall of the mask frame, and the other end of which is fitted to the stud pin (9), and a dissimilar metal is bonded. It consists of a bimetal (8b). However, elastic support (8)
Are arranged for each side of the rectangular mask frame (7), so that when manufacturing a color picture tube or
The shadow mask (5) and the mask frame (7) whose temperature has risen during operation tend to be twisted around their central portions. That is, the corners of the mask frame (7) are easily moved, which is very inconvenient for defining the landing position of the electron beam on the phosphor layer.

Therefore, it is necessary to use a material having a relatively large plate thickness as the material of the mask frame (7). If this plate thickness is large, the frame weight becomes heavy, and the elastic support body is subjected to an external impact. There is a risk that strong force will be applied to the mask and the mask support part may be deformed.

To address such inconvenience, Japanese Patent Application No. 60-10654 has been proposed by the same applicant as the present application. As shown in FIG. 5, this is supported by the corner elastic supports (8) arranged one by one at the corners of the rectangular mask frame (7). By doing so, twisting of the shadow mask, that is, displacement of the landing position due to the twisting is suppressed without increasing the weight of the mask frame. For example, in the case of a 28-inch 110-degree deflection color picture tube, in the case of a shadow mask supporting method as shown in FIG. 4, the mask frame needs to have a thickness of about 1.6 mm, but as shown in FIG. Supporting it at the corners of the (panel) can reduce the thickness of the mask frame to about 0.8 mm. However, the demand for ultra-large color picture tubes has recently increased, and it is about twice as large as the 28-inch display area.
A 42-inch class color picture tube is also being developed. Therefore, as shown in FIG. 5, even if the structure is supported at the corners, the weight of the mask frame must be increased.
The rigidity is weakened, and there is a possibility that the mask may be deformed particularly near the center of the long side.

(Problems to be Solved by the Invention) As described above, in the case of a super-large color picture tube, it is not possible to sufficiently hold the shadow mask and the frame at the predetermined positions only by the structure that supports the shadow mask and the frame at the corners of the panel. In addition, the weight of the frame is too heavy to maintain their rigidity.

An object of the present invention is to provide a color picture tube having a high color purity by using a mask frame having a smaller plate thickness than that of a conventional one even in a large color picture tube without causing twisting or deformation.

[Structure of Invention]

(Means for Solving Problems) According to the present invention, a shadow mask having a frame is attached to the four corners of the elastic support, and second elastic supports are attached to opposite sides of the frame. Both of the elastic supports have at least a movable piece having a predetermined angle with the tube axis, and the angle between the movable piece of the elastic support at the corner and the tube axis is the first. 2 is a shadow mask type color picture tube that is smaller than the angle formed by the movable piece of the elastic support 2 and the tube axis.

(Operation) The provision of the second elastic support and the angle α between the movable piece of the second elastic support and the tube axis are defined by the angle between the movable piece of the elastic support at the corner and the tube axis. By making the angle larger than the angle α, it is possible to uniformly correct the positional deviation of the landing due to the thermal expansion of the shadow mask over the entire screen, and even in a large color picture tube or an elastic support or The twist and deformation of the shadow mask are suppressed.

(Example) Hereinafter, an example of the color picture tube of the present invention will be described in detail with reference to the drawings.

FIG. 2 is a vertical sectional view of a color picture tube according to the present invention. As is apparent from FIG. 2, the vacuum envelope is composed of the substantially rectangular panel (10) and the funnel-shaped funnel (12) and neck (13). Then, a phosphor screen (14) consisting of striped phosphor layers emitting red, green and blue respectively is adhered and formed on the inner surface of the panel (10), and the panel (10) is formed on the neck (13).
A so-called in-line type electron gun (16) is arranged which is arranged in a row along the horizontal axis of the above and emits three electron beams (20) corresponding to red, green and blue. Further, at a position close to and facing the phosphor screen (14), a peripheral portion thereof is supported by a mask frame, and a large number of slit-shaped apertures are arranged in the vertical direction, and the vertical arrangement is arranged in a large number in the horizontal direction. The shadow mask (15) is supported on the inner surface of the panel by a stud pin (19) via an elastic support (18).

The electron beams (20) arranged in three lines are deflected by a deflection device (21) outside the funnel (12) to scan a rectangular area corresponding to the rectangular panel (10), and a shadow mask (15). The colors are selected through the apertures and landed on the striped phosphor layer to reproduce a color image. In addition, the electron beam (20) may not accurately land on the stripe-shaped phosphor layer due to the influence of an external magnetic field such as the earth's magnetism, so that the color purity of the reproduced image is prevented from deteriorating inside the funnel (12). A magnetic shield (22) made of a ferromagnetic metal plate is locked via a mask frame (17).

Further, the supporting structure of the shadow mask and the mask frame will be described in detail with reference to FIGS. 1 and 3.

FIG. 1 is a diagram showing a main part of FIG. That is, the rectangular mask frame (17) equipped with the shadow mask (15) has six elastic supports (18a), (18a), (18).
It is elastically supported in the panel (10) by a), (18a), (18b), and (18b). As shown in FIG. 3, each of the six elastic supports has a movable piece (181) having an angle of α (degrees) with the tube axis (40) and has one edge on the outer surface of the side wall of the mask frame (17). Is stuck. The other end edge is fitted to a metal pin (19) protruding from the inner surface of the side wall of the panel (10). The four corner elastic supports support the mask frame (17) equipped with the shadow mask at the four corners of the panel (10), and the second elastic support (18b) is the mask frame (1).
The mask frame (17) is supported so as to face the center of the long side of (7).

It has been confirmed that such a supporting system makes it possible to use a mask frame having a thickness of 0.8 mm or less even in a 42-inch type color picture tube of 110-degree deflection. That is, the broken line (47) in FIG. 1 indicates the outer dimensions of the mask frame used in the 28-inch type 110-degree deflection color picture tube. ) Has an outer diameter dimension about twice that of the mask frame (47) for 28-inch color picture tube.
That is, the major-axis dimension Lh and the minor-axis outer diameter dimension Lv of the mask frame (17) for the 42-inch color picture tube are about 810 mm and 610 mm, respectively. On the other hand, the outer diameter dimension of the mask frame (47) for 28-inch color picture tube (minor axis direction)
v and the major axis direction lh are about 400 mm and 530 mm, respectively.
It can be seen that the area surrounded by the outer diameter of the mask frame (17) for the inch type color picture tube is more than twice the area surrounded by the outer diameter of the mask frame (47) for the 28 inch type color picture tube. Since the mask frame (17) is supported by four corner elastic supports (18a) at four corners and a pair of second elastic supports (18b) at its long sides, the mask frame (17) The rigidity of 17) is a 28 inch type color picture tube,
The result is equal to or higher than when the mask frame is supported at the four corners. For example, the mask frame for this 42-inch color picture tube is a cold rolled steel plate with a thickness of 0.8 mm, and the weight is about
It is 1.6 kg. However, when the mask frame of the 42-inch type color picture tube is supported by one elastic support at each center of each side as shown in FIG. Twisting occurs at the corners of the frame and the electron beam does not land correctly on the phosphor layer. Therefore, in order to make the rigidity substantially the same as that of the conventional 28-inch color picture tube, the material thickness must be 2.3 mm or more. In this case, the weight is about 4.8 kg, which is about three times that of the present invention. It turned out to be. As described above, the thick and heavy frame is not only disadvantageous in terms of cost and manufacturing, but also the elastic support and the stud pin for supporting the mask frame are large and heavy. It is a double demerit that you cannot get it.

By the way, according to the present invention, the corner of the mask frame, that is,
Although it is premised that the mask frame is supported at the corners of the rectangular panel, the size of the elastic support body is naturally limited because the space is small at the corners. In particular, a spring piece using a slender bimetal which is parallel to the sides of the mask frame is very inconvenient, and a simple elastic support as shown in the embodiments of the present invention is particularly convenient. That is, as shown in FIG. 3, an elastic support (1) having at least a movable piece (181) forming an angle α with the tube axis (40).
When the corner portion of the mask frame (17) is supported by 8), a part of the shadow mask (15) undergoes thermal expansion so as to move from P to P'and is pressed so that the angle α becomes smaller. 15) is P ′ on the phosphor screen (14) side.
It is possible to return to the position of the normal electron beam (20) by moving from the position to the position of Q without using the bimetal.
The angle α between the movable piece (181) of the elastic support (18) and the tube axis (40) has already been filed by the same applicant as this application, but the shadow mask (1
When the material of 5) and the mask frame (17) are the same, it has been found that effective correction is possible by determining by the following formula. That is, tan (α) ≈0.6tan (90−B) (1).

Here, the angle β is substantially the angle formed by the electron beam (20) and the tube axis (40) flying to the transmission hole at the outermost effective end of the shadow mask near the elastic support (18). Is. Therefore, when the corner elastic supports are provided in the diagonal portions of the 110-degree deflection type color picture tube as described above, the angle β = 55 ° and the angle α are optimally 48 ° from the above formula (1).
Further, as in the present invention, the angle of the movable piece of the second elastic support that supports the opposite sides of the mask frame is set to an angle that moves the shadow mask by the same amount as the elastic support at the corner. Must. That is, in the case of the embodiment shown in FIG. 1, since the second elastic support member supports the mask frame at the center of the long side portion, the mask outer diameter lm has a mask diagonal diameter larger than the vertical diameter. The amount pressed by the corner elastic support is small, and it is necessary to increase the angle α accordingly. However, this angle α need only be corrected by the difference in the outer diameter lm of the mask, and the angle α of the second elastic support in FIG.
Good correction was obtained by setting it to 62 °.

However, similarly to the present invention, for the purpose of using a mask frame having a relatively small thickness, one elastic member is provided for each of two opposite sides of the rectangular mask frame as shown in FIG. 6 (a). A support (48b) is provided, and two elastic supports (48a) are provided for each of the other two opposite sides.
The above-mentioned arrangement is already disclosed in JP-A-60-109144. With this arrangement, 2 on the side
Since individual elastic supports (elongate spring pieces in the embodiment) are arranged, as shown in FIG. 6 (b), the elastic support (48a) mounting position represented by hm, hs, hg is elastic. Support (48
a), it is troublesome that the difference in the thermal expansion characteristics due to the difference in the materials of the panel (41) and the mask frame (47) must be fully taken into consideration, and this poses a very disadvantageous problem in terms of industrial quantity. In this respect, according to the present invention, since the mask frame is always supported at the corners thereof, even in a 42-inch super-large color picture tube, only one pair of elastic supports is provided on the other side, and the mask frame is made thin. It can be said that the purpose is to be achieved, there is almost no annoyance as in the prior art, and the mass productivity is high. Even if the present invention is adopted and two or more elastic supports are to be arranged on one side of the mask frame, it is not the conventional elongated spring piece, but the one shown in FIG. If an elastic member having at least a movable piece that makes an angle α with the tube axis as shown is used, the mask frame and the elastic support shown in FIG. Distance hs from body attachment to stud pin center
Since it becomes zero, the mounting position can be determined more easily than in the past.

〔The invention's effect〕

According to the present invention, not only can the thin material of the mask frame for mounting the shadow mask be used, but also the twisting of the mask frame during manufacturing or use of the color picture tube can be reduced, and industrial mass productivity can be improved. Rich and good color purity characteristics can be obtained, and the effect is remarkable especially in a large color picture tube.

[Brief description of drawings]

FIG. 1 is a front view of a main part showing an embodiment of a color picture tube of the present invention, FIG. 2 is a sectional view of a color picture tube illustrating an embodiment of the present invention, and FIG. 3 is a color picture of the present invention. An enlarged cross-sectional view of an essential part of an embodiment of the picture tube, FIGS. 4 and 5 are front views of the essential part for explaining a conventional color picture tube, and FIG. 6 (a) is a main part of the conventional color picture tube. Front view, FIG. 6 (b) is FIG. 6 (a)
FIG. (10) …… Panel, (12) …… Funnel, (13) ……
Neck, (14) …… phosphor screen, (15) …… shadow mask, (16) …… electron gun, (17) …… mask frame, (18) …… elastic support, (18a) …… corner Part elastic support, (18b) ... second elastic support, (181) ... movable part.

Claims (1)

[Claims] 1. A substantially rectangular panel, a vacuum envelope in which a funnel-shaped funnel and a neck are connected to each other, and a phosphor screen provided on the inner surface of the neck for exciting and emitting light. An electron gun for emitting a plurality of electron beams and a shadow mask having a substantially rectangular frame suspended and supported at four corners of the panel by a plurality of corner elastic supports so as to closely face the phosphor screen. In the color picture tube provided, a second elastic support is provided on opposite sides of the shadow mask.
The shadow mask is suspended and supported in the panel by the elastic support member and the corner elastic support member, and the elastic support member includes at least a movable piece that makes an angle with the tube axis.
A color picture tube characterized in that the angle formed by the movable piece of the elastic support at the corner and the tube axis is smaller than the angle formed by the movable piece of the second elastic support and the tube axis.