KR100671756B1 - Panel for cathode ray tube - Google Patents

Abstract

The present invention relates to a windshield for a cathode ray tube. The windshield of the present invention comprises a face portion, a skirt portion extending rearward from the edge of the face portion and having a seal edge having a compressive stress layer formed by physical strengthening, and a blend round portion connecting the face portion and the skirt portion. . The compressive stress (σ) ranges from 5 MPa < 17 < 17 MPa so that the stress on the inner and outer surfaces of the seal edge can have sufficient breakdown time against external mechanical impact, and the compressive stress range of the first and second long sides of the seal edge is Greater than short side According to the present invention, in the windshield formed with a compressive stress layer by physical reinforcement, the stress distribution of the skirt portion is improved to withstand external mechanical shocks well, and thus, it has an effect of having a safer shape during explosion proof testing.

Description

Front glass for cathode ray tube {PANEL FOR CATHODE RAY TUBE}

1 is a cross-sectional view showing a glass bulb for a cathode ray tube composed of a front glass and a rear glass, a neck,

Figure 2 is a rear view showing the position of the stress measuring portion and the first to fourth corner portion of the windshield,

Figure 3 is a rear view of the windshield to test the stability by giving a random scratch on the inner surface of the first to fourth corner portion of the windshield in order to apply a mechanical impact,

Figure 4 is a perspective view showing the damage form of the first to fourth corner portion of the windshield generated by the mechanical impact.

♣ Explanation of symbols for the main parts of the drawing ♣

10: glass bulb 12: windshield

14: Face part 16: Seal edge

18: skirt part 20: blend round part

22, 24: first and second long sides 26, 28: first and second short sides

30 ° 36: first to fourth corner portions 38: rear glass

40: neck

The present invention relates to a cathode ray tube windshield (Panel), and more particularly to a cathode ray tube windshield for improving the stress magnitude of the skirt portion of the windshield to maintain a safe form even mechanical impact.

Glass Blubs for Cathode Ray Tubes used in the manufacture of color televisions and computer monitors are basically three components: windshields through which images are projected, conical funnels, and tubular necks. ) The windshield, back glass and neck are all made of glass, and in particular the windshield and back glass are produced by press molding a molten glass mass called a gob in a desired size and shape.

Referring to the configuration of the glass bulb for the cathode ray tube based on FIG. 1, the front glass 12 of the glass bulb 10 has a face portion 14 for displaying an image and a rear portion from the edge of the face portion 14. A skirt portion (Skirt Portion 18) having a seal edge (Extension 16) extending to the face, and a Blend Round Portion (20) connecting the face portion 14 and the skirt portion 18. .

As shown in FIG. 2, the windshield 12 is formed into a substantially rectangular shape having a first long side 22, a second long side 24, a first short side 26, and a second short side 28. The windshield 12 has first to fourth corner portions 30, 32, 34, and 36.

Referring back to FIG. 1, the conical rear glass 38 is bonded to the seal edge 16 of the skirt 18, and the neck 40 is bonded to the vertex of the rear glass 38. Tube 42 is windshield

The center of the face part 14 of 12 and the center of the neck 40 are shown. A shadow mask 44 having a plurality of holes in the skirt portion 18 of the windshield 12 is supported by a stud pin 46, and the neck 40 is provided through a hole of the shadow mask 44. An electron gun 48 which emits an electron beam with an imaging phosphor coated on an inner surface of the face portion 14 is provided.

The blend round portion 20 connecting the face portion 14 and the skirt portion 18 of the windshield 12 has the maximum vacuum tensile stress due to the pressure difference between the inside and the outside of the glass bulb 10. This working area has a fragile structure. In addition, since the glass is weak in tensile stress due to its characteristics, the glass bulb 10 has a maximum vacuum tensile stress of not more than one third less than the breakdown strength of the glass bulb 10 in consideration of the long life of the cathode ray tube. It has been designed to be.

Recently, as the size and planarization of the cathode ray tube increases, the thickness and weight of the glass bulb 10 are inevitably increased. Therefore, in order to reduce the weight of the glass bulb 10, the shape of the windshield 12 is improved to alleviate or reduce the vacuum tensile stress distribution due to the pressure difference.

On the other hand, the glass bulb for cathode ray tube of U.S. Patent No. 5,445,285 forms a compressive stress layer on the surface of the windshield by physically strengthening method to improve glass strength, and consequently to cope with the maximum vacuum tensile stress caused by the pressure difference between the inside and outside of the glass bulb The technique which prevents thermal breakage during the manufacture of a glass bulb and fatigue destruction after completion is proposed. Moreover, the technique which prescribed | regulated the relational expression between a compressive stress and a tensile stress is proposed in the glass bulb for cathode ray tubes of Unexamined-Japanese-Patent No. 11-96941.

However, according to the range of compressive stresses by the physical reinforcement methods proposed in these prior arts, the mechanical strength of the glass is improved by the compressive stress, but inevitably an increase in strain energy results in the failure of the glass bulb. Shrinkage, that is, serious problems in which explosion-proof properties such as explosive shrinkage and scattering of windshield and rear glass are degraded, and spontaneous breakage may occur due to surface defects generated in a specific portion of the glass bulb due to unbalance of stress.

Moreover, in the windshield manufactured by the physical strengthening method, the temporal stress formed when molded from the product is controlled in a slow cooling furnace and cooled to room temperature. In the prior art in which the compressive stress is formed on the surface, the windshield could not have a uniform stress distribution. In particular, in the blend round part of the windshield, the distribution of air flow in the heated slow cooling furnace is different between the face area and the skirt area. Could not keep shape. In addition, there was a problem that the explosion-proof characteristics of the UL standard (Underwriters Laboratories Inc.) is reduced.

The present invention has been made to solve the problems of the prior art as described above, the object of the present invention is to control the compressive stress range of the skirt portion safe to maintain the form of the windshield in the original state from the external mechanical impact It is to provide a windshield for the cathode ray tube.

A feature of the present invention for achieving the above object is a skirt portion having a face portion, a seal edge extending rearward from the edge of the face portion and having a compressive stress layer formed by physical reinforcement, and the face portion and the skirt portion. In the cathode glass tube windshield composed of the blend round portions to be connected, the compressive stress (σ) is in the range of 5 MPa < σ < 17 MPa so that the stress on the inner and outer surfaces of the seal edge can have a sufficient breakdown time even from an external mechanical impact. The seal glass has a compressive stress range of the first and second long sides greater than the short side in the windshield for cathode ray tubes.

The compressive stress? Range of the seal edge is 5 MPa < σ < 12 MPa.

Hereinafter, a preferred embodiment of the windshield for cathode ray tube according to the present invention will be described in detail.

Referring to FIG. 1, in the embodiment of the present invention, the compressive stress value of the seal edge 16 of the windshield 12 is controlled by the holding temperature and time in the slow cooling furnace and the cooling rate of the scud part 18. The stress values applied to the inner and outer surfaces were adjusted. The stress of the scud part 18 measured the area | regions (A) and (B) shown in FIG. 2 by the Senarmont method.

In the stress distribution of the seal edge 16 physically strengthened according to the heat treatment conditions, the first and second long sides 22 and 24 having a relatively large length are generally compared to the first and second short sides 26 and 28. The stress is large. By varying the heat treatment conditions in the slow cooling furnace by position, the stress distribution around the skirt portion 18 and the first to fourth corner portions 30 ?? 36 was made different.

On the other hand, a scratch test was carried out to find the extent to which the windshield 12 corresponds to external mechanical shock. In the scratch test, as shown by the arrows in FIG. 3, the first and fourth corner portions 30 are applied after the scratches are arbitrarily applied to the inner surfaces of the first to fourth corner portions 30 ?? 36. 36) records the time when the glass is broken and cannot take the form of the windshield 12. Figure 3 shows a scratch test to apply a mechanical impact optionally in the direction of the arrow on the inner surface according to the stress magnitude of the skirt portion 18 according to the present invention. In tests such as explosion proof, external shocks are dynamic tests that occur quickly for a short time.

As shown in FIG. 4, in the process of applying the predetermined compressive stress to the windshield 12, the magnitude of the tensile stress due to temporary torsion in the skirt portion 18 of the windshield 12 is applied to the given compressive stress magnitude. It is proportional to, and as a result, shows a fracture form that occurs in the first to fourth corner portions 30 ?? 36 of the windshield 12 during the scratch test.

The present invention forms a compressive stress layer by physical reinforcement on the seal edge 16 of the windshield 12, and compressive stress (σ) so that the stress of the seal edge 16 can have a sufficient time even in the external mechanical impact The windshield 12 of which the range of 5 MPa <σ <17MPa was manufactured. When the compressive stress of the seal edge 16 is less than 5MPa, the compressive stress applied to the entire glass bulb 10 is small, so that the stress is similar to that of the slow cooling product, so that the reinforcing effect is not seen. It occurs around the first to fourth corner portions 30 ?? 36 and is likely to break due to inadvertent mechanical shock. As a heat treatment method to control the temperature between the strain point at the transition temperature of the glass to have a stress distribution as shown in the example in Table 1.

Table showing compressive stress distribution of seal edges according to Examples 1, 2, 3 and Comparative Example 4 Zone (A) Zone (B) First long side First short side Second long side 2nd short side First long side First short side Second long side 2nd short side Example 1 9 7 9 5 6 6 6 5 Example 2 12 11 12 10 6 6 6 6 Example 3 17 14 17 13 11 12 10 11 Comparative Example 4 27 19 27 18 17 17 17 14

Table showing scratch break time according to compressive stress distribution of seal edges according to Examples 1, 2, 3 and Comparative Example 4 division 1st corner part 2nd corner part Third corner part 4th corner part Example 1 Not broken Not broken Not broken Not broken Example 2 After 300 seconds Not broken Not broken Not broken Example 3 After 300 seconds After 300 seconds 300 seconds After 300 seconds Comparative Example 4 0 sec 0 sec 0 sec 0 sec

As can be seen from Table 1 and Table 2, when the stress of the skirt portion 18 is excessively high, the first to fourth corner portions 30 ?? 36 are immediately broken even when a mechanical shock is applied with a slight force. As shown in Examples 1, 2, and 3, when the compressive stress around the skirt portion 18 and the first to fourth corner portions 30 ?? 36 is adjusted, the shape of the windshield 12 can be maintained even for a relatively long time. It has a safe form, such as keeping or breaking.

As described above, according to the cathode ray tube windshield according to the present invention, in the windshield in which the compressive stress layer is formed by physical reinforcement, the stress distribution of the skirt portion is improved, so that it can withstand external mechanical shocks and is more safe in explosion proof testing. It has the effect of having a form.

Claims (3)

The windshield for cathode ray tube comprising a face portion, a skirt portion extending rearward from the edge of the face portion and a seal edge having a compressive stress layer formed by physical strengthening, and a blend round portion connecting the face portion and the skirt portion. To The compressive stress (σ) is in the range of 5 MPa &lt; The windshield for cathode ray tube, characterized in that the range is larger than the short side. delete The cathode glass tube windshield according to claim 1, wherein the seal stress has a compressive stress range of 5 MPa &lt;

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