JPH0685298B2 - Shade mask structure manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to a manufacturing apparatus for a sheer mask structure, and more particularly to a sheer mask surface wherever a flat sheer mask is provided for improving the color purity reproduction characteristics of the sheer mask type color picture tube. The present invention relates to an apparatus for manufacturing a shed mask structure that is stretched around a mask frame in a state in which uniform tension (hereinafter simply referred to as uniform tension) is applied in all directions.

[Technical background of the invention and its problems]

Generally, in a shadow mask type color picture tube, red,
The three electron beams corresponding to green and blue pass through one electron beam passage hole of the shed mask, and then irradiate each of the red, green and blue phosphor layers formed on the inner surface of the panel facing the shed mask. Then, each phosphor layer is caused to emit light.

Therefore, in order to perform good color reproduction, it is necessary to accurately land the electron beam that has passed through a large number of electron beam passage holes of the shadow mask on a predetermined phosphor layer.

However, the electron beam has a transmittance of the shadow mask of 15 to 20%, and most of the other electron beams impinge on the shadow mask to heat and expand the shadow mask. This heat expansion becomes extremely large when the anode voltage or the beam current of the color picture tube is increased in order to obtain a particularly bright screen, and as a result, the beam landing position is largely changed and the color purity is deteriorated.

Next, an example of an ordinary shadow mask type color picture tube will be described with reference to FIG.

That is, a panel (1) having a phosphor screen (2) formed by adhering a phosphor layer that emits red, green and blue light on the inner surface,
A shadow mask structure (5) including a shadow mask (3) arranged on the fluorescent screen (2) at a predetermined interval and a mask frame (4) to which the shadow mask (3) is fixed, and the shadow mask structure (5). It is composed of a support structure (6) for supporting the panel pin (6) and an electron gun (9) provided in the neck (8).

In such a color picture tube, the shadow mask (3) is made by press-molding a thin iron plate of 0.1 to 0.2 mm, which is provided with a large number of electron beam passage holes by etching or the like, into a dome shape and has a thickness of 0.5 to 1.5 mm. It is welded and fixed to the mask frame (4) at a plurality of points to form a shed mask structure (5).

As described above, a part of the electron beam (10) emitted from the electron gun (9) passes through the electron beam passage hole of the shadow mask (3) and strikes the phosphor screen (2), so that a predetermined phosphor Allows the layers to emit light, but most of the rest is a shadow mask (3)
To heat the shed mask (3). And
Due to this heating, the temperature of the sheer dough mask (3) rises and expands, and this heat is further transferred from the mask frame (4) and the mask support structure (6) to the panel (1), so that the temperature difference in each part. Occurs, the component is deformed, and a so-called landing error occurs in which the position at which the electron beam (10) is landed on the fluorescent screen (2) through the electron beam passage hole portion is changed from a predetermined position.

The amount of displacement of the landing position is about several tens of μm to 100 μm, which causes deterioration of color purity. Further, as the anode voltage of the color picture tube is increased and the beam current is increased in order to obtain a bright screen, the energy that collides with the shadow mask (3) also increases, resulting in a large landing error and a marked deterioration in color purity.

On the other hand, in order to realize a high-definition image, it is necessary to reduce the mutual interval between the electron beam passage holes of the shadow mask (3) to increase the number of picture elements. This reduces the spacing between the three color phosphor layers deposited on the phosphor screen (2) and the landing margin of each phosphor layer. Therefore, a more accurate color picture tube requires more accurate beam landing.

In order to reduce the beam landing error mentioned above,
Various proposals have been made in the past. For example, the structure of blackening the shadow mask or black coating to improve heat dissipation and reduce the temperature rise, adjustment of the thickness and length of the shadow mask side wall, or the provision of holes, notches, etc. There are structures that reduce the heat capacity to achieve uniform heating, and structures that use low thermal expansion materials such as amber. However, these measures are not sufficient for applications that require high brightness, such as airplanes and vehicles, which are used under bright external light.

RC Robinder's “A High Brightness Shadow−Mask Color CRT for Coc
kbit Displays, Digest of paper of1983 Symposium of
The Society for Information Display 9,5 has announced a color picture tube equipped with an improved sheer mask structure.

The color picture tube comprises a flat sheer dough mask (3) which is tensioned and secured to the mask frame (4) as shown in FIG.

Next, the operation of this color picture tube will be briefly described. That is, the shadow mask (3) is fixed to the mask frame (4) in a state where tension is applied in the surface direction. In this state, internal stress commensurate with the applied tension is remarkable in the shear mask (3). When the picture tube is operated as described above, the shadow mask (3) thermally expands. In the picture tube having the stretched shadow mask (3), the thermal expansion is absorbed by the internal stress relaxation of the shadow mask (3). Therefore, the shear mask (3) does not deform until the internal stress is completely relieved. Therefore, a picture tube with a small beam landing error can be realized.

As can be seen from the above description, the larger the applied tension at the time of fixing to the mask frame (4), the larger the internal stress of the shear mask (4), and the difference in landing word does not occur up to high brightness. It is desirable to apply to (3). Since the upper limit of this applied tension is determined by the breaking strength of the shear mask (3),
It is an important problem to control the tension of the stretched sheave mask (3) to a predetermined value. Therefore, a means for detecting the tension applied to the shadow mask (3) is required. However, there is no effective means for detecting the applied tension of the shear mask (3) in a non-destructive manner.

[Object of the Invention]

INDUSTRIAL APPLICABILITY The present invention can provide a high-luminance color picture tube without deterioration in color purity by realizing a manufacturing apparatus for a sheer mask structure having means for nondestructively detecting the applied tension of a sheer mask to which a tension is applied in the surface direction. It is an object.

[Outline of Invention]

That is, the resonance frequency detector is arranged so as to form a capacitor between the tension mask and the shear mask, the capacitance change due to the vibration of the shear mask is detected, the resonance frequency of the shear mask is determined, and the applied tension is determined. This is a manufacturing apparatus for a sheer mask structure that stretches the sheer mask on a mask frame when the tension reaches a predetermined value.

Example of Invention

Next, one embodiment of the manufacturing apparatus for the sheer mask structure of the present invention will be described with reference to FIGS.

That is, the circular openings (22), (23) having an inner diameter ( _DH ) in the center
, And a pair of presser plates (15) and (16) having rubber plates (17) and (18) attached to the opposing surfaces thereof, in which electron beam passage holes are regularly provided on the entire surface. The peripheral part of (13 ₁ ) is clamped and fixed. The rubber plates (17) and (18) are provided to prevent the shear mask (13 ₁ ) from moving when a tension is applied to the shear mask material (13 ₁ ).

On the other hand, the pressing plate support plate (24) (15), but on the surface of oppositely arranged cylindrical frame (25) is provided in (16), an outer diameter (D _R of the cylindrical frame (25) ) Is selected so as to be smaller than the inner diameter ( _DH ) of the circular openings (22) and (23) of the holding plates (15) and (16), and when the support plate (24) is moved in the axial direction. ,
The cylindrical frame (25) is inserted into the circular openings (22) and (23) with a predetermined gap. In addition, the cylindrical frame (2
The height of 5) is that the presser pin (28) is inside this cylindrical frame (25).
The height of the welded part (14 ₁ ) of the mask frame (14) fixed by is set to be slightly lower than the height. A resonance frequency detector (32) is fixed on the support plate (24) corresponding to the axis of the cylindrical frame (25). The upper part of the resonance frequency detector (32) is composed of a metal plate (32 ₁ ), and the metal plate (32 ₁ ) is lowered parallel to the surface of a shadow mask portion (13 a) described later and at a predetermined interval. It is designed to form a capacitor.

A support rod (29) is fixed to the base (31). The support rod (29) can move the support plate (24) in the axial direction, and also holds the shear mask material (13 ₁ ) to the holding plate (15). ), (1
6) It is designed to be sandwiched and fixed between them. Further base (3
Vertical movement by moving the support plate (24) between the support plate (24) and the support plate (24) to bring the holding plates (15), (16) and the support plate (24) close to and away from each other using hydraulic pressure or air pressure. Feeder (30)
Is provided.

Next, a process of forming a shed mask structure with this shed mask manufacturing apparatus will be described with reference to the same drawings.

First, Shiyadoumasuku material as shown in FIG. 2 (13 ₁₎ through the support rod (29) holding plate (15) is sandwiched and fixed between (16). Support plate at this point (24) is lowered to the extent that the cylindrical frame (25) and the weld of the mask frame (14) (14 ₁₎ top and Shiyadoumasuku material is slightly spaced apart.

Next, when the vertical feed device (30) is operated as shown in FIG. 3, the support plate (24) moves in the direction of approaching the holding plates (15) and (16), and the shear mask material (13 ₁ ) Due to the relationship between the pressing plates (15) and (16) and the cylindrical frame body (25), a uniform tension is applied in the entire circumferential direction while being bent at the outer periphery of the top of the cylindrical frame body (25). The shadow mask material in the cylindrical frame (25) at this time is referred to as shadow mask portion (13a).

In this step, when the shear mask portion (13a) is forcibly vibrated and its vibration frequency is continuously changed, the shear mask portion (13a) vibrates with a large amplitude at its resonance frequency. This vibration causes the shadow mask area (13
Since the capacitance of the capacitor to be formed by a) the metal plate (32 ₁₎ is changed can be known resonance frequency of Shiyadoumasuku site by detecting this capacitance change in the resonant frequency detector (32) (13a). That is, there is a relationship of T = k · f ² between the applied tension T and the resonance frequency f, as can be seen from the membrane vibration theory, and the applied tension is obtained from the resonance frequency f. Here, k is a constant determined by the material, shape, and size of the shadow mask portion (13a). A known one such as an electromagnet can be used for the forced vibration, and it can be incorporated in the resonance frequency detector (32).

In this way, when the predetermined tension is applied to the shadow mask portion (13a), the welded portion (14) of the mask frame (14)
_The ribbon mask (26) corresponding to ( ₁ ) is aligned with the weld mask portion (13a) on the weld mask portion (13a) and densely welded at the welding point (27) to complete the shear mask structure.

In the above-described embodiment, the case where the vibration frequency of the shadow mask portion (13a) is continuously changed has been described.
It is also possible to automatically detect the resonance frequency by causing the vibrating means to feed back the detected capacitance change. By detecting the applied tension in a non-contact manner, it is possible to always apply a predetermined tension without causing damage such as deformation to the shear mask.

Further, although the vertical feed device is used as the device, it goes without saying that a press machine or the like may be used.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide an apparatus for manufacturing a sheer mask structure that can easily manufacture a good quality sheer mask structure to which uniform tension is applied in advance so as to prevent a landing error due to thermal expansion of the sheer mask.

[Brief description of drawings]

1 to 3 are views showing an embodiment of a manufacturing apparatus for a sheave mask structure according to the present invention. FIG. 1 is a perspective view of an essential part, and FIG. 2 is a state before a uniform tension is applied to a shed mask material. FIG. 3 is a cross-sectional view showing a state in which a uniform tension is applied to the sheer mask material and is sandwiched and fixed between the mask frame and the ribbon frame. FIG. 4 is a cross-sectional view of a conventional sheer mask type color picture tube. FIG. 5 is a sectional view for explaining the main part of another example of the conventional shade mask type color picture tube. 3 …… Shead mask, 13 ₁ …… Shed mask material 13a …… Shed mask part, 15, 16 …… Holding plate 24 …… Support plate, 25 …… Cylindrical frame 27 …… Welding point, 28 …… Holding pin 29 …… Support rod, 30 …… Vertical feed device 31 …… Base, 32 …… Resonance frequency detector 32 ₁ …… Metal plate

Claims (1)

[Claims] 1. A pair of holding plates which hold a peripheral edge portion of a sheer mask material having electron beam passage holes regularly and which has an opening at the center, and a support plate which is opposed to the holding plates. And a holding pin for supporting a cylindrical frame body having an outer diameter smaller than the opening of the holding plate and a mask frame provided inside the cylindrical frame body, and a resonance frequency. A detector and at least a moving mechanism for moving the holding plate and the supporting plate relatively close to and away from each other, and when the holding plate and the supporting plate come close to each other, the holding plate and the tubular frame body are used to At least the shear mask portion of the shear mask material is vibrated, the resonance frequency is detected by the resonance frequency detector, and a predetermined tension is applied, and then a predetermined portion of the shear mask portion is reattached to the mask frame. Manufacturing apparatus Shiyadoumasuku structure, characterized in that is configured so as to be able to secured clamped by down-like frame.