KR100369975B1 - Shadow mask in flat cathode ray tube and methode for bonding thereof - Google Patents

Abstract

The present invention relates to a shadow mask for a flat cathode ray tube and a fixing method thereof. The present invention provides a shadow mask for a flat cathode ray tube having an effective surface formed with a plurality of slits for color discrimination of an electron beam, and an invalid surface continuously extending from the effective surface without a slit to the periphery, and having a welding line formed for attachment to a rail A shadow mask for a flat cathode ray tube and a fixing method thereof are provided, wherein a cutting aid hole of a predetermined shape is formed at each boundary edge of an effective surface and an invalid surface of the shadow mask. According to the present invention, the cutting process of the ineffective surface of the shadow mask is performed quickly and accurately.

Description

SHADOW MASK IN FLAT CATHODE RAY TUBE AND METHODE FOR BONDING THEREOF}

The present invention relates to a planar cathode ray tube, and more particularly, to a shadow mask for a planar cathode ray tube positioned behind a cathode ray tube panel and serving as color screening, and a method of fixing it to a rail at a predetermined distance from the panel.

In general, cathode ray tubes are applied to television receivers, video display devices, and the like. In particular, flat cathode ray tubes have been rapidly increasing in popularity due to the advantage of reducing the distortion of the screen compared to curved CRTs and outputting images close to the true screen.

The configuration and operation of such a planar CRT will be briefly described with reference to FIG. 1 as follows.

It is formed by a flat panel 1 having a safety glass 2 bonded to its front surface and a bulb shaped funnel 3 bonded to a rear surface of the panel by frit glass. Its interior maintains a high vacuum of about 10 ^-7 Torr.

In the inner space formed by the panel 1 and the funnel 3, a square frame rail 4 is joined to the rear surface of the panel 1, and the rail 4 has a slit or air gap shape. The mask 5 in which the micropores 5a are formed innumerably is fixed in the tensioned state.

In addition, the neck portion 3a formed behind the funnel 3 includes an electron gun 6 which emits an electron beam (thermal electrons) according to an image signal of red, green, and blue, and the neck portion 3a. The deflection yoke 8 is formed on the outer side of the N-axis to deflect the electron beam 7 by forming a uniform magnetic field in the vertical / horizontal direction.

The planar CRT having such a configuration includes a phosphor 1a in which electron beams of three primary colors of red, green, and blue are applied to the inner surface of the panel 1 as an image signal of primary color is applied to a cathode (not shown) of the electron gun 6. Emitted towards.

The emitted electron beam 7 is blocked by the shadow mask 5 located on its emission path (about 85%), and the electron beam (about 15%) required for image reproduction passes through the beam of the shadow mask 5. The color image is reproduced by colliding with the final red, green and blue phosphor 1a through the ball 5a.

Looking at the configuration of the shadow mask 5 before attaching to the rail 4 in detail, as shown in Figure 2, the shadow mask 5 is a thin metal plate attached to the rail (4), functionally It can be divided into two parts, the effective surface 5b and the ineffective surface 5c.

The effective surface 5b includes a plurality of beam passing holes 5a for screening colors by passing through the beam 7 from the electron gun 6, and are almost identical to the size of the screen implemented in the color cathode ray tube. The ineffective surface serves as a welding portion for fixing the shadow mask 5 to the rail 4.

A method of actually fixing a shadow mask for a flat cathode ray tube having such a configuration to the rail is briefly described as follows.

When the shadow mask 5 is fixed to the rail 4, the mask is tightly pressed against the surface of the rail 4, and the contact portion between the rail 4 and the shadow mask 5 is fixed by welding. Done. After the completion of the welding process, the ineffective surface 5c of the shadow mask 5 is cut off.

In this case, if the ineffective surface 5c is not cut out, the ineffective surface 5c covers the upper surface of the rail 4, as shown in FIG. It is impossible to weld a damping wire or an inner shield. Further, even if possible, the welding failure of the damping wire or the inner shield occurs due to the interference with the ineffective surface 5c.

As such, there may be various methods for cutting the unnecessary ineffective surface 5c of the shadow mask 5, but the method of manually cutting using a cutting tool such as a cutter is most commonly used.

In this manual cutting method, as shown in Fig. 4A, during cutting of the ineffective surface 5c, the operator usually designates any cutting line by the eye mass at a point about 2.5 mm outward from the welding line w, Accordingly, the ineffective surface 5c is cut.

At this time, it should be noted that the welded portion of the mask 5 and the rail 4 should not fall, foreign matters should not be generated during cutting, and the cutting line should be smooth and parallel to the outer peripheral surface of the rail 4. However, in order to satisfy the above conditions, a high degree of skill is required, otherwise a defect occurs that adversely affects the quality of the product.

Meanwhile, as an alternative for reducing such defects, a method of automatically cutting and cutting the non-effective surface 5c using a laser has been introduced.

In general, it is the ideal working method to cut the laser by moving it in a straight line and it takes less time.However, due to the characteristics of the laser that melts the object to heat, the shadow mask (5) A stop section is generated, which causes the intersections to melt together.

Therefore, in order to compensate for this fatal flaw, a method of moving the laser while drawing an arc near a corner was used as shown in FIG. 4B so that the stop section of the laser does not occur.

However, this cutting method has to continuously calculate and control the movement path of the laser in the corner portion, so the movement speed of the laser is reduced to less than half of the straight portion, which causes a relatively long working time.

In addition, the remaining edge portion 5d after cutting makes it difficult to couple between the rail 4 and the inner shield, and when the edge portion 5d is too large, it protrudes out of the inner shield to reduce the shielding effect of the inner shield. . In addition, the magnetic field of the edge portion of the shadow mask 5 is disturbed by the reduction of the shielding effect, thereby degrading the characteristics of the screen edge portion.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a shadow mask for a planar cathode ray tube and a method of fixing such a shadow mask, in which unnecessary invalid surfaces can be cut quickly and accurately.

1 is a longitudinal sectional view of a general flat CRT.

2 is a top view of a typical flat cathode ray tube shadow mask prior to a cutting process.

3 is a cross-sectional view illustrating a state after a welding process of the shadow mask of FIG. 2.

4A is a perspective view showing an invalid surface cutting process of a shadow mask with a cutting tool.

4B is a perspective view illustrating an invalid surface cutting process of a shadow mask by a laser.

5 is a plan view showing a first embodiment of a shadow mask for a planar cathode ray tube according to the present invention.

6 is a plan view showing a second embodiment of a shadow mask for a planar cathode ray tube according to the present invention.

<Description of main parts of drawing>

5: shadow mask 5a: beam through hole

5b: effective surface 5c: invalid surface

5e: circular cutting aid 5f: elliptical cutting aid

W: welding line L: distance to welding line

According to one aspect of the present invention for achieving the above object, an effective surface formed with a plurality of slits for color discrimination of the electron beam, and continuously extending from the effective surface without a slit to the periphery, forming a welding line for attaching to the rail In a shadow mask for a flat cathode ray tube having an effective surface, a shadow mask for a flat cathode ray tube is provided, wherein a cutting aid hole of a predetermined form is formed at each boundary edge of the effective surface and the invalid surface of the shadow mask.

Here, the cutting aid hole may be circular, when D is the diameter of the circular cutting aid hole, the diameter of the cutting aid hole is in the range of 0.7mm <D <5mm, L is the circular cutting aid hole When the distance between each coordinate axis set at the center of the welding line and the welding line, it is preferable that the center of the cutting aid hole is located within a range satisfying D / 2≤L≤2.5mm.

In addition, the cutting aid hole may be an elongate ellipse, when a is the short axis length of the elliptical cutting aid, b is the long axis length of the elliptical cutting aid, the elliptical cutting aid is 0.25 <a / b <1 It is desirable to satisfy the relationship. More preferably, the short axis length of the cutting aid hole should be within the range of 0.7mm <a, the long axis length of the cutting aid hole is b <5mm, and the center of the cutting aid hole should be a / 2≤L≤2.5. It should be located within the range satisfying mm.

On the other hand, according to another aspect of the present invention, a tensile force of a predetermined size or more in each axial direction is applied to a shadow mask having a cutting aid hole at each corner of the boundary between the effective surface and the invalid surface using the aspect of the present invention. Adding; Aligning the tensioned shadow mask on a rail attached to the panel such that the beam passthrough coincides with the fluorescent surface of the panel; Securing the shadow mask to a rail by welding the invalid surface along the effective surface; And separating a portion of the ineffective surface from the fixed shadow mask by cutting between the beam through holes, thereby providing a method of fixing a shadow mask for a flat cathode ray tube.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention in which the above objects can be specifically realized are described with reference to the accompanying drawings. In describing the present embodiment, the same name and the same reference numerals are used for the same configuration and additional description thereof will be omitted below.

5 shows a first embodiment of a shadow mask for a planar cathode ray tube according to the present invention, and FIG. 6 shows a second embodiment of the shadow mask. The structure of the shadow mask of the present invention will be described in detail with reference to these accompanying drawings.

First, as shown in FIGS. 5 and 6, the shadow mask 5 according to the present invention has the effective surface 5b and the effective surface including a plurality of beam passing holes 5a as a whole, as in the conventional shadow mask. It consists of an ineffective surface 5c extending continuously from 5b to the periphery thereof. The ineffective surface 5c includes a welding line W formed when the shadow mask 5 is fixed by welding the shadow mask 5 to the rail 4, and the welding line W is preferably the effective surface 5b. Is formed at a certain distance from the boundary of the effective surface (5b) so as not to interfere with.

Under this basic structure, the shadow mask 5 according to the present invention has a predetermined shape of cutting aid holes 5e and 5f formed at four corners of the boundary formed between the effective surface 5b and the ineffective surface 5c. It is made to include more. More specifically, the cutting aid holes 5e and 5f are located outside the welding line W formed at the boundary between the effective surface 5b and the ineffective surface 5c. In the cutting operation of the non-effective surface 5c by the laser by the cutting auxiliary holes 5e and 5f, the non-effective surface 5c can be cut only by the linear movement of the laser.

First, as shown in FIG. 5, in the shadow mask according to the first embodiment of the present invention, the cutting auxiliary holes 5e may be formed in a circular shape.

Here, in order to increase the efficiency of the cutting operation, the larger the size, that is, the diameter (D) of the cutting auxiliary hole (5e) is advantageous. However, when the cutting aid hole 5e having a predetermined size or more is formed in the tension mask shadow mask 5 for the planar cathode ray tube, the stress is concentrated around the maximum principal stress and the yield stress exceeds the yield stress. 5) the probability of tearing increases. Therefore, it is important to determine the maximum diameter at which the stress generated around the cutting aid hole 5e when the tensile force is applied becomes less than the yield stress. In practice, in the shadow mask for flat cathode ray tubes, according to the stress analysis results, when the diameter of the cutting aid hole 5e becomes 5 mm or more, the possibility of tearing of the shadow mask 5 during tension increases. In addition, when the diameter of the cutting auxiliary hole (5e) is less than the laser diameter (0.7mm), melting may occur during the cutting operation and the cutting line may occur to deviate from the cutting auxiliary hole (5e).

Therefore, the diameter of the circular cutting aid hole 5e according to the first embodiment is preferably present in the following 0.7 mm &lt; D &lt; 5 mm range.

In addition, in addition to the size of the above-described cutting auxiliary hole 5e for proper cutting operation, the position of the cutting auxiliary hole 5e should be considered.

As shown in FIG. 5, it may be assumed that the cutting line by the laser generally passes through the center of the cutting auxiliary hole 5e. More specifically, it can be seen that the cutting line is formed along a local Cartesian coordinate axis set at the center of each cutting auxiliary hole 5e. Under this assumption, the distance L represents the distance between each rectangular coordinate axis set at the center of the circular cutting aid hole 5e and the welding line W, and approximately the width of the remaining ineffective surface 5c after the cutting operation. This can be

In this case, the cutting auxiliary hole 5e may not be formed at a position substantially interfering with the welding line W. For this purpose, the distance L should be greater than or equal to a predetermined size. That is, as shown in FIG. 5, when the distance L is at least 1/2 of the diameter D of the cutting aid hole 5e, that is, the radius d or more, the welding line W does not interfere. It may be located at an appropriate point. If the distance L corresponding to the width of the remaining ineffective surface 5c is larger than a predetermined size, more specifically, 2.5 mm, welding of the inner shield or damping wire is impossible as described above.

Therefore, the cutting aid hole 5e is preferably positioned so that its center is within a range satisfying D / 2? L? 2.5 mm.

On the other hand, the shape of the cutting aid is ideally circular as in the first embodiment, but it is also possible to have an ellipse as shown in Figure 6 showing a second embodiment of the present invention.

Here, the edge portion where the cutting auxiliary hole 5f is located, as described above, acts simultaneously with the X-axis force and the Y-axis force on the entire coordinates of the shadow mask 5 during the stretching, and the beam passage hole 5a. The Y-axis elastic modulus (Eyy) is larger than the X-axis elastic modulus (Exx) due to the geometrical characteristics of the shadow mask 5 such as the array direction. Therefore, since it is possible to withstand a greater force in the Y-axis direction, when the beam through hole 5f has an elliptic shape, the beam-passing hole 5f should be substantially longer in length in the Y-axis direction than the X-axis length. In addition, since the Y-axis elastic modulus is substantially 3-4 times larger than the X-axis elastic modulus, the elliptical cutting auxiliary hole 5f has a relationship between the short axis length (a) and the long axis length (b) of 0.25 <a /. It is preferable that it is formed so as to satisfy the relationship of b <1.

In addition, in the size of the elliptical cutting auxiliary hole (5f), the long axis length (b) is less than 5mm in order to prevent excessive stress concentration, and the short axis length (a) is 0.7mm in order to prevent the problem of pressing during cutting Larger is preferred. Since the selection criteria are the same as those of the circular cutting aid hole 5e according to the first embodiment of the present invention, detailed description thereof will be omitted.

Also, in the position of the elliptical cutting auxiliary hole 5f, first, as shown in FIG. 6, since the short axis of the cutting auxiliary hole 5f is closest to the welding line, the length L is the elliptical cutting. It should be at least 1/2 of the short axis length a so that the auxiliary hole 5f does not interfere with the welding line W. In addition, as described above, the length L should be 2.5 mm or less so that the inner shield can be stably attached to the rail 4. Therefore, it is preferable that the elliptical cutting aid hole 5f according to the second embodiment of the present invention is positioned so that its center is within a range satisfying a / 2≤L≤2.5mm.

As described above, the shadow mask for a planar cathode ray tube according to the present invention has a configuration in which an invalid surface can be cut quickly and accurately, and a method of substantially fixing a shadow mask having such a configuration to the rail is as follows. Can be explained.

First, the shadow mask 5 for the planar cathode ray tube is subjected to a tensile force of a predetermined size.

The tensile force is added by holding and pulling each axial clearance of the ineffective surface 5c with a predetermined gripping means, and with respect to the long axis (X axis) and short axis (Y axis) directions of the shadow mask 5. It is applied uniformly throughout. This tensile force prevents welding deformation from occurring in the shadow mask 5 and prevents the doming phenomenon caused by the collision of the electron beam during operation.

The tensioned shadow mask is then aligned and positioned on a rail attached to the panel.

In the alignment step, the beam passing hole 5a in the effective surface 5b is actually aligned with the fluorescent surface 1a of the panel 1 by a predetermined positioning means so that the screen can be accurately realized. do.

After the alignment step, the shadow mask is fixed on the rail by welding.

The welding process is performed so that deformation due to thermal stress and residual stress does not occur in the shadow mask 5, whereby a weld line W is formed on the ineffective surface 5c.

After completion of the welding step, a part of the ineffective surface 5c is finally separated from the shadow mask 5.

In the cutting step, the non-effective surface 5c has an appropriate width by cutting between the cutting aid holes 5e and 5f with a laser. As described above, the cutting process by the cutting aids 5e and 5f may be quickly performed by the linear motion of the laser. By using the appropriately positioned cutting aids 5e and 5f, the cutting process can be made precisely so that the ineffective surface 5c has a uniform width as a whole.

In addition, this fast and accurate cutting operation reduces the working time of the cutting process, which overall increases the efficiency of the shadow mask fixing operation itself.

On the other hand, since the fixed shadow mask 5 has a shape in which the corners are substantially recessed by the cutting aids 5e and 5f, the fixing operation of the inner shield, which is a post-process of the fixing operation, is easily performed. In addition, since the width of the remaining portion of the ineffective surface 5c is accurate and constant, the inner shield fixing operation is more easily and accurately performed. In addition, the magnetic shielding capability of the inner shield is improved by such an accurate fixing operation, thereby preventing deterioration of the screen characteristics of the edge portion.

Although only a few embodiments have been described herein above, it will be apparent to those skilled in the art that the present invention may be embodied in many other specific forms without departing from the spirit and scope thereof. Therefore, the above-described embodiments are to be considered as illustrative and not restrictive, and thus, the invention is not limited to the above detailed description, but may vary within the scope of the appended claims and their equivalents.

When explaining the effect of the present invention.

First, the cutting operation during the series of shadow mask fixing operations can be efficiently performed by the present invention.

In the shadow mask according to the present invention, the cutting process is performed quickly only by the linear motion of the laser, and is accurately performed so that the remaining invalid surface has a uniform width as a whole. This rapid and accurate cutting operation thus reduces the working time of the cutting process and also increases the efficiency of the shadow mask fixing operation itself as a whole.

Secondly, by using the shadow mask according to the present invention, the post process of the fixing operation is easily performed.

That is, the fixing operation of the inner shield is made easy and accurate by the shape of the fixed shadow mask, that is, the uniform width of the recessed edge portion and the non-effective surface residual portion. In addition, the magnetic shielding ability of the inner shield is improved by such an accurate fixing operation, and thus, there is an additional effect of preventing deterioration of the screen characteristics of the edge portion.

Claims (9)

An effective surface having a plurality of slits for color discrimination of the electron beam, A shadow mask for a flat cathode ray tube having a non-effective surface extending continuously from the effective surface to the periphery without a slit and forming a welding line for attaching to a rail, And a cutting aid is formed at the edge of the boundary of the effective and ineffective surfaces of the shadow mask. The method of claim 1, The shadow mask of the planar cathode ray tube, characterized in that the cutting aid hole is circular. The method of claim 2, When D is the diameter of the circular cutting aid, A shadow mask for flat cathode ray tubes, characterized in that the diameter of said cutting aid hole exists in the range of 0.7 mm <D <5mm. The method of claim 2, When L is the distance between each coordinate axis set at the center of the circular cutting aid and the weld line and D is the diameter of the circular cutting aid, A shadow mask for a flat cathode ray tube, characterized in that the center of the cutting aid is located within a range satisfying D / 2≤L≤2.5mm. The method of claim 1, The shadow mask for a flat cathode ray tube, characterized in that the cutting aid is an elongate ellipse. The method of claim 5, a is a shorter length of the elliptical cutting aid, when b is the long axis length of the elliptical cutting aid, The shadow mask for a flat cathode ray tube, characterized in that the elliptical cutting auxiliary hole satisfies the relationship of 0.25 <a / b <1. The method of claim 6, A shadow mask for a flat cathode ray tube, characterized in that the short axis length of said cutting aid hole exists in the range of 0.7mm <a <5mm, and the long axis length of the cutting aid hole exists in the range of 0.7mm <b <5mm. The method of claim 7, wherein A shadow mask for a flat cathode ray tube, characterized in that the center of the cutting aid is located within a range satisfying a / 2≤L≤2.5mm. Applying a tensile force of at least a predetermined magnitude in each axial direction to the shadow mask having cutting aid holes at each boundary edge between the effective and ineffective surfaces; Aligning the tensioned shadow mask on a rail attached to the panel such that the beam passthrough coincides with the fluorescent surface of the panel; Securing the shadow mask to a rail by welding the invalid surface along the effective surface; And And separating a portion of the non-effective surface from the fixed shadow mask by cutting between the beam passing holes.