KR20020000085A - Mask frame assembly of crt - Google Patents

Abstract

PURPOSE: A mask frame assembly of a CRT is provided to be capable of easily applying tension force to a shadow mask as well as decreasing the thickness of a mask frame, thereby realizing a compact and light CRT and selectively applying the tension force without being distributed, as well as preventing the deformation due to high temperature. CONSTITUTION: A shadow mask(4) has mask holes(4a) for passing through an electron beam emitted from an electron gun. Supporting members(60,60') are welded to long sides of the shadow mask(4) to support the shadow mask(4). Bridges(10,10') are connected between the supporting members(60,60'). Tension adjusting devices(20,20') connect the supporting members(60,60') to control the distance between the supporting members, thereby applying tension force to the shadow mask(4).

Description

Mask frame assembly of cathode ray tube

The present invention relates to a mask frame assembly of a cathode ray tube, and more particularly to a mask frame assembly of a cathode ray tube that can be easily applied to the tension-type shadow mask to reduce the thickness.

In the cathode ray tube, the electron beam emitted from the electron gun has a color discrimination function, and is landed on the fluorescent film through the electron beam through hole of the shadow mask which is spaced apart from the fluorescent film by a predetermined distance, thereby exciting the fluorescent film to form an image.

The screen surface of the conventional cathode ray tube forming the image as described above is designed to have a predetermined curvature in consideration of the deflection trajectory of the electron beam when the electron beam emitted from the electron gun is deflected by the deflection yoke, and thus the shadow mask screen surface It is designed to have a curvature that corresponds to the curvature of. In the conventional cathode ray tube, a shadowing mask is heated by an electron beam, ie, hot electrons, emitted from the electron gun, and a swelling phenomenon occurs in the panel side. This doming phenomenon causes the electron beam not to land on the fluorescent film accurately, and is formed to have a predetermined curvature on the screen surface, so that the viewing angle is narrowed and the image is distorted at the edge of the screen surface.

In order to solve the problems as described above, the planar cathode ray tube having a flat screen surface is formed on a flat plate with a fluorescent film formed thereon and fixed to the panel in a state where a predetermined tensile force is applied to the shadow mask. When a tensile force is applied, the doming can be minimized. In this state, the panel is fixed with a funnel equipped with an electron gun and a deflection yoke.

FIG. 7 illustrates an example of a mask frame assembly in which a shadow mask is mounted in the planar cathode ray tube. The shadow mask frame having the above structure is a model mainly applied to US 5421c380, US 5532546, US 57021a80, and the like filed by Sony of Japan.

In the figure, the shadow mask frame assembly 2 of the conventional planar cathode ray tube is largely divided into the shadow mask 4, the support members 6, 6 'and the rigid members 8, 8'. The supporting members 6 and 6 'are simple beams having an approximately L-shaped cross section, and the material mainly uses an alloy such as chromium-molybdenum steel. An approximately U-shaped rigid member 8, 8 'is welded to the lower ends of both ends of the support members 6, 6'.

The rigid members 8 and 8 'have a hollow square tube shape and are curved at a predetermined distance from the welded ends of the supporting members 6 and 6'. The rigid members 8, 8 'are usually made of a material which is elastic and does not have a high coefficient of thermal expansion.

The shadow mask 4 is attached to the upper surface of the supporting members 6 and 6 ', and the long side end 4a of the shadow mask is welded and attached. At this time, the shadow mask 4 is applied a tensile force in the axial direction of the short side and the rigid member (8) (8 ') is to support the tensile force.

However, when the rigid members 8 and 8 'are usually manufactured in a U-shape to support the tensile force of the shadow mask 4 and assembled to the face panel of the cathode ray tube, the rigid members 8 and 8' are out of the face panel. In order to solve this problem, the face panel has to be thick, the production cost increases, and the appearance of the CRT becomes poor.

In addition, when a tensile force is applied to the shadow mask 4 depending on the elastic force of the rigid members 8 and 8 ', there is a problem that it is difficult to impart a desired tensile force due to its large scattering property.

The present invention is a newly proposed invention to solve the above-described problems of the prior art, and to provide a mask frame assembly of a cathode ray tube that can easily give a tensile force to the shadow mask, and can reduce the thickness of the mask frame. do.

In order to achieve the above object, a mask frame of a cathode ray tube according to the present invention includes a shadow mask through which an electron beam emitted from an electron gun passes; A support member for supporting the shadow mask; A tension force adjusting device which connects and couples the support members to adjust the distance between the support members, thereby providing a tensile force to the shadow mask; It consists of a configuration including a bridge provided between the support member.

The tension control device is characterized in that the screw rod employing a turn buckles or nuts.

The tensile force adjusting device is characterized in that the thermal expansion coefficient is at least equal to or greater than the bridge.

The thermal expansion coefficients of the shadow mask, bridge, and tension control device are respectively And the distance between the shadow mask and the bridge at a certain temperature If the distance between the tension control device and the bridge ( ) Satisfies the following formula.

The mask frame assembly of the cathode ray tube having the above-described configuration can manufacture the cathode ray tube slim because the entire thickness thereof does not exceed the thickness of the supporting member, and the tensile force of the desired bar on the shadow mask by simply turning the joint or tightening the nut. Can be given.

1 is an exploded perspective view showing a preferred embodiment of the mask frame assembly of the cathode ray tube according to the present invention.

2 is a perspective view showing a turnbuckle according to the present invention;

3 is a side view of a mask frame assembly of a cathode ray tube according to the present invention;

4 is a view showing another example of a contact portion of a turnbuckle and a mask frame according to the present invention.

5 is a graph of thermal expansion rate, thermal expansion amount, and spacing between members of a mask frame assembly according to the present invention;

Figure 6 is a side view showing another embodiment of the mask frame assembly of the cathode ray tube according to the present invention.

Figure 7 is an exploded perspective view showing a mask frame assembly of a conventional cathode ray tube.

** Explanation of symbols for main parts of drawings **

4: shadow mask 4a: mask hole

10,10 ': Bridge 20,20': Tensile force regulator

60,60 ': support member

The structure of this invention is demonstrated in detail, referring an accompanying drawing. For reference, in order to avoid duplication of description, parts consistent with the prior art will be referred to as prior reference numerals.

Example 1

Figure 1 shows an exploded view of a preferred embodiment of the mask frame assembly of the cathode ray tube according to the present invention.

Referring to the drawings, the mask frame assembly of the cathode ray tube includes a shadow mask 4 having a mask hole 4a through which an electron beam emitted from an electron gun passes; Support members (60, 60 ') for supporting the shadow mask (4) by welding the long sides of the shadow mask (4); Bridges (10) (10 ') that are connected in simple contact by pressure between the support members (60, 60'); It is made of a tension force control device 20, 20 'to connect between the support members 60, 60' but to adjust the length to impart a tensile force to the shadow mask (4).

The shadow mask 4 is a component installed in front of the face panel of the cathode ray tube, and as shown in the drawing, a plurality of mask holes 4a through which an electron beam passes are formed. The electron beam passes through the mask hole 4a and strikes the fluorescent surface of the face panel. At the peripheral edge of the shadow mask 4, there is a non-perforated portion 4b in which no mask hole 4a is formed, which is welded to the upper surface of the supporting members 60 and 60 ', which will be described later.

The supporting members 60 and 60 'are a part for supporting the shadow mask 4, and as shown in the drawing, a general cross-section has a' b 'shape. A non-perforated portion 4b in which the mask hole 4a is not formed among the long sides of the shadow mask 4 on the upper surfaces of the vertical portions 60a and 60'a, which are upright from the support members 60 and 60 '. Is welded. The inner shield of the cathode ray tube is attached to the back surface of the horizontal parts 60b and 60'b horizontally extended to the inner side facing the support members 60 and 60 'by a welding method or a hole assembly. do.

The support members 60 and 60 'are provided with tensile force adjusting devices 20 and 20' and bridges 10 and 10 'in a direction facing each other. The primary member to be joined is the tension force control device 20, 20 ′. The tension force adjusting device 20, 20 'and the bridge 10, 10' is installed at both ends of the side of the support members 60, 60 '.

The length of the support members 60 and 60 'is formed to be longer than the long side of the shadow mask 4, and the shadow mask 4 is formed outside the weld joint of the shadow mask 4 and the support members 60 and 60'. The tension force adjusting device 20, 20 'and the bridge 10, 10' is provided in a range that does not overlap with 4).

2 shows the tension control device 20 in a perspective view.

In this embodiment, a turn buckle 21 is used as the tension control device 20. The turnbuckle 20 is a substrate having two screw rods composed of a right hand screw 22 on one side and a left hand screw 24 on the other side of the turnbuckle 20 using a joint 26 as a medium. Depending on the direction in which the joint 26 of the turnbuckle 20 is rotated, the overall length may be increased or decreased. As shown in FIG. 1, the turnbuckle 20 has a ring 28 in a ring hole 61, 61 ′ provided at a lower side of a vertical portion 60a, 60 ′ a of the support members 60, 60 ′. To install. The method of fixing the turnbuckle 20 to the support members 60 and 60 'may adopt various methods such as welding, screwing, gear coupling, etc. as well as the ring coupling method.

3 is a cross-sectional view taken in the A-A direction from the exploded perspective view of FIG.

In the figure, a shadow mask 4 is attached to the upper surface of the upper surface of the support members 60 and 60 'and directly above the lower horizontal portions 60b and 60'b of the support members 60 and 60'. The turnbuckle 20 shown in Fig. 2 is fixedly attached to the opposing surfaces of the supporting members 60, 60 '. At this time, the bridge 10 is installed at the upper end at a predetermined interval with the turnbuckle 20. In order to install the bridge 10, bridge grooves 60c and 60'c must be formed as shown in FIG. do.

In this embodiment, the shape of the bridge grooves 60c and 60'c is formed in a cone shape. The bridge grooves 60c and 60'c have an internal shape such that the bridges 11 having sphere-shaped ends can be inserted as shown in FIG. 4 according to the shape of the bridges 10 and 10 '. Various attempts can be made in the form of a spherical bridge groove (60d) having a spherical shape such as to reduce the ease and spread of the work process.

Looking again at the shape of the bridge 10 shown in FIG. 1, except for both ends, the rod 10 has a circular cross section. Both ends of the bridge 10 have a similar cone shape so that they can be inserted into the bridge grooves 60c and 60'c and end portions of the bridge 10 inserted into the bridge grooves 60c and 60'c. Is sharply cut into dots.

As shown in the cross-sectional view of Fig. 3, the cross-sectional angles of the bridge grooves 60c and 60'c are formed to be approximately 1.2 times or more larger than the cross-sectional angles of the insertion portions of the bridges 10 (10 '). The support members 60 and 60 'may be slightly rotatable with the contact portions of the 10' and the bridge grooves 60c and 60'c as axes.

Hereinafter, referring to the cross-sectional view of FIG. 3, a method of selectively providing tensile strength by using the turnbuckle 20, which is a tension control device, will be described.

As shown in the figure, after the bridges 10 and 10 'are inserted into the bridge grooves 60c and 60'c of the support members 60 and 60', both support members 60 and 60 'are arranged in parallel. The hook 28 of the turnbuckle 20 is fixed to the ring hole 61 installed in the vertical portions 60a and 60'a of the support members 60 and 60 '. After fixing the turnbuckle 20, both sides of the long side of the shadow mask 4 are welded to the upper surfaces of the vertical parts 60a and 60'a of the support members 60 and 60 '. In this way, the mask frame assembly has a structurally stable configuration.

In this structure, since the shadow mask 4 is not in a tension state yet, in order to impart the tensile force to the shadow mask 4, the joint 26 in the center of the turnbuckle 20 is tightened. When the joint 26 is turned, the length of the turnbuckle 20 is reduced since the right screw 22 and the left screw 24 are tightened to the center at the same time. As the length of the turnbuckle 20 decreases, the distance between the support members 60 and 60 'at the bottom of the bridge 10 relative to the bridge 10 decreases, and thus the support members 60 and 60 at the upper portion of the bridge 10 are reduced. ') The interval is forced to increase. That is, while the lower end of the bridge 10 receives a compressive force, the upper end of the bridge 10 receives a tensile force.

The above structure is possible because the bridge 10 is inserted into contact with the bridge grooves 60c and 60'c of the support members 60 and 60 'by point coupling. This is because the movement of the support members 60 and 60 'can be caused by the rotational movement of the support members 60 and 60' as the axis of the coupling point between the bridge 10 and the bridge grooves 60c and 60'c. In this way, the operator can easily give the shadow mask 4 a tensile force of a desired bar easily by only tightening or releasing the turnbuckle 20.

The mask frame assembly having the above structure is subjected to a plurality of heat treatment processes in the production process. If the materials of the shadow mask 4, the bridge 10, and the turnbuckle 20 are different from each other, the thermal expansion coefficients of the shadow mask 4, the bridge 10, and the turnbuckle 20 are different. have. When such plastic deformation occurs, even when the shadow mask 4 is cooled, the mask surface changes into a wrinkle shape.

The problem can be solved by adjusting the installation position of the tension force adjustment device by the formula described below.

5 shows the relationship between the coefficient of thermal expansion, the amount of thermal expansion and the spacing of the members. In the drawing, l represents the length of the short side of the mask frame, and T is the temperature increase of the mask frame assembly. Is the thermal expansion coefficient of the shadow mask 4, Is the thermal expansion coefficient of the bridge 10, Is the thermal expansion rate of the tension control device 20, the length of each member is increased by thermal expansion is as follows.

When the distance d ₁ between the shadow mask 4 and the bridge 10 is set, the distance d ₂ between the bridge 10 and the tension adjusting device 20 which can prevent plastic deformation from occurring is It is determined as follows.

When the tension force control device 20 is installed by d ₂ determined as described above, the tension force applied to the shadow mask 4 can be kept constant regardless of the change in temperature.

Example 2

Figure 6 is a side cross-sectional view of the mask frame assembly using another embodiment of the tension force adjustment device 20 related to the present invention.

Referring to the drawings, the shadow mask 4, the support members 60, 60 ', and the bridge 10 of the mask frame assembly are not different from those of FIG. 1, but the turnbuckle 20 is used as the tension adjusting device 20. There is a difference installed by employing the screw rod 200 and the nut 202, rather than).

When the screw rod 200 is installed, one side is fixedly coupled to the support member 60 'and the other side is fitted with a nut 23a from the outside of the support member 60 to be variable. When the screw rod 200 is fixedly coupled to the support member 60 ', a simple coupling method such as a welding method or a groove is formed to be engaged. The threaded end of the screw rod 200 is drawn out to the outside through the hole (60e) of the support member and by tightening the nut 202 to the end of the drawn screw rod 200, the turnbuckle (Fig. 1) It plays the same role as 20).

The screw rod 200 of the above embodiment is also installed at a position that can satisfy the distance d ₂ between the bridge 10 and the tension adjusting device 20 calculated by the drawing and the equation of FIG.

In the first embodiment and the second embodiment, the bridge 10 and the tension adjusting device 20, 200 are one pair at both ends of the short sides of the supporting members 60, 60 'within the range of not overlapping with the shadow mask 4. Since the tensile force of the two sides are not exactly matched, the deformation may occur in the shadow mask (4). Accordingly, all of the tensile force adjusting devices 20 and 200 can be manually operated, but it is desirable to secure quality reliability by additionally adopting a tensile amount measuring device and an electronic control device.

The mask frame assembly of the cathode ray tube having the same structure as the above-described embodiments can reduce the overall thickness of the frame, resulting in a slim manufacture of the cathode ray tube and the cathode ray tube, and can provide a tensile force more easily. .

The thickness and weight of the mask frame assembly can be reduced to reduce the thickness and weight of the cathode ray tube, and can selectively provide a tensile force without scattering the tensile strength, and prevent deformation of the shadow mask due to high temperature.

Claims (8)

A shadow mask through which an electron beam emitted from the electron gun passes; A support member for supporting the shadow mask; A tension force adjusting device which connects and couples the support members to each other, but adopts screws to adjust a gap between the support members; Mask frame assembly of the cathode ray tube, characterized in that it comprises a bridge installed between the support member. 2. The mask frame assembly of claim 1, wherein the tension control device is a turnbuckle. 2. The mask frame assembly of claim 1, wherein the tension adjusting device is a screw rod and a nut combination. The mask frame assembly of claim 1, wherein the bridge is in point, line, or surface contact with the support member but is not fixedly bonded. The mask frame assembly of claim 1, wherein the tensile force adjusting device has a larger coefficient of thermal expansion than the bridge. The method of claim 1, wherein the thermal expansion coefficients of the shadow mask, the bridge, and the tension control device are respectively And the distance between the shadow mask and the bridge at a certain temperature If the distance between the tension control device and the bridge ( ) Is a mask frame assembly of a cathode ray tube, characterized in that: 5. The mask frame assembly of claim 4, wherein the bridge has a larger volume of the bridge groove of the support member than the bridge contact portion to enable the support member to move. 5. The mask frame assembly of claim 4, wherein the bridge is in linear, circular or spherical surface contact.