Patent Grant
6998768
The present invention relates to a formed type flat panel for use in a cathode ray tube (CRT); and more particularly, to a tinted formed type flat panel, satisfying the UL (Underwriters Laboratories Inc.) standard for implosion resistance thereof.
Nowadays, flat panels have been widely employed in color cathode ray tubes (CRTs) intended for use in television sets, computer monitors or the like, replacing the conventional spherical/parabolic panels, for enhanced visibility and reduction of glare due to reflection of external light.
Referring to
In contrast to the formed type flat panel, a tension type flat panel made of tinted glass uses a tension mask as a shadow mask. The tension type flat panel has a low wedge rate. That is, both external and inner surfaces are virtually flat, thus difference in thickness between a center portion and periphery portion of a faceplate portion thereof is considered negligible.
The formed type flat panel, however, has high wedge rate, and thus there exists a non-uniformity in light transmittance (or absorption) between the periphery portion and the central portion thereof. Consequently, it further leads to non-uniform brightness of image displayed thereon. To overcome such non-uniformity in brightness, intensity of brightness is increased over the entire faceplate portion of the formed type flat panel by making the formed type flat panel with clear glass, and in addition, coating the external surface of the faceplate portion in a manner that the high light absorption takes place in the central portion of the formed type flat panel while low absorption takes place in the periphery portion thereof.
Such a method described above, however, has some drawbacks as follows. First, the additional panel coating process incorporated in a procedure for fabricating the formed type flat panel inevitably raises the manufacturing cost.
Moreover, production of clear glass for clear formed type flat panels required in some applications alternately shares the glass melting furnace used for producing tinted glass gob for tinted formed type flat panels. Accordingly, such sharing process suffers from a tank color conversion loss, which occurs during a transition from one process to another, i.e., switching from a process for making clear glass gob for clear formed type flat panels to a process for making tinted glass gob for tinted tension type flat panels or vice versa. In practice, it takes several days to make such transition resulting in a significant loss of productivity.
Various efforts in making the formed type flat panel with the tinted glass have been attempted. However, the light transmittance of the formed type flat panel made of tinted glass is less than that of the formed type flat panel made of clear glass, accordingly arriving at an approach of making the thickness of the entire faceplate portion thinner than that of the faceplate portion made of clear glass so as to satisfy the tube makers' standard for brightness. While satisfying the brightness standard, such product made of tinted glass being thinner fails to meet the implosion resistance of the formed type flat panel.
It is, therefore, an object of the present invention to provide a tinted formed type flat panel while satisfying the UL (Underwriters Laboratories Inc.) standard for implosion resistance thereof.
In accordance with a preferred embodiment of the present invention, there is provided a formed type flat panel made of tinted glass, including: a substantially rectangular faceplate including an effective picture plane, an external surface having a radius of curvature of R being equal to or greater than 10,000 mm and a curved inner surface having a radius of curvature R1, R1 being smaller than R; a skirt portion extending backward from a periphery of the faceplate; a corner portion joining the faceplate and the skirt portion; wherein a diagonal length D of the effective picture plane is equal to or greater than 700 mm, or equal to or greater than 550 mm but less than 665 mm, and
0.03D−5≦T1≦0.039D+15/(D0.5−1.5)+2.54
0.0185D−6.5≦T2≦0.0204D
1.3≦T1/T2≦2.1
wherein T1 is a periphery thickness of the faceplate, and T2 is a center thickness of the faceplate.
In accordance with another preferred embodiment of the present invention, there is provided a formed type flat panel made of tinted glass, including: a substantially rectangular faceplate including an effective picture plane, an external surface having a radius of curvature of R being equal to or greater than 10,000 mm and a curved inner surface having a radius of curvature R1, R1 being smaller than R; a skirt portion extending backward from a periphery of the faceplate; a corner portion joining the faceplate and the skirt portion; wherein a diagonal length D of the effective picture plane is equal to or greater than 665 mm but less than 700 mm, and
0.03D−5≦T1≦0.039D+15/(D0.5−1.5)+2.54
0.0185D−6.5≦T2≦0.0204D
1.3≦T1/T2≦1.97
wherein T1 is a periphery thickness of the faceplate, and T2 is a center thickness of the faceplate.
In accordance with still another preferred embodiment of the present invention, there is provided a formed type flat panel made of tinted glass, including: a substantially rectangular faceplate including an effective picture plane, an external surface having a radius of curvature of R being equal to or greater than 10,000 mm and a curved inner surface having a radius of curvature R1, R1 being smaller than R; a skirt portion extending backward from a periphery of the faceplate; a corner portion joining the faceplate and the skirt portion; wherein a diagonal length D of the effective picture plane is equal to or greater than 500 mm but less than 550 mm, and
0.03D−((0.003D)2−2.54)−5≦T1≦0.07D−((0.004D)4−2.54)+1.2
0.031D−(0.004D)2≦T2≦0.056D−(0.007D)2−0.254
1.3≦T1/T2≦2.1
wherein T1 is a periphery thickness of the faceplate, and T2 is a center thickness of the faceplate.
In accordance with still another preferred embodiment of the present invention, there is provided a formed type flat panel made of tinted glass, including: a substantially rectangular faceplate including an effective picture plane, an external surface having a radius of curvature of R being equal to or greater than 10,000 mm and a curved inner surface having a radius of curvature R1, R1 being smaller than R; a skirt portion extending backward from a periphery of the faceplate; a corner portion joining the faceplate and the skirt portion; wherein a diagonal length D of the effective picture plane is less than 500 mm, and
0.035D−((0.003D)2−2.54)−5≦T1≦0.07D−((0.004D)4−2.54)
0.031D−(0.004D)2−3.5≦T2≦0.056D−(0.007D)2+1.5
1.3≦T1/T2≦2.1
wherein T1 is a periphery thickness of the faceplate, and T2 is a center thickness of the faceplate.
The above and other objects and features of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:
A formed type flat panel 20 in accordance with a preferred embodiment of the present invention will now be described with reference to the accompanying drawings.
Referring to
Referring to
The thickness of the faceplate 12 at the point of tangency is referred to as a faceplate periphery thickness T1. In other words, T1 is a thickness of the faceplate 12 at the point where the inner surface 12a having the radius of curvature R1 meets the inner surface 16a having a radius of curvature R2. The center of the faceplate 12 is a point where an extended axis of a neck (not shown) meets the faceplate 12 and also a point where two diagonals of the effective picture plane 22 intersect. The thickness at the center of the faceplate 12 is referred to as a faceplate center thickness T2.
A tinted glass for use in fabricating a tinted formed type flat panel in accordance with the present invention yields a light transmittance of about 52.5±5% when having a thickness of 11.43 mm.
In accordance with the present invention, a formed type flat panel can be made of the tinted glass while satisfying tube makers' standard for brightness uniformity (BU) and the UL standards for implosion resistance, in case dimensions, i.e., the periphery thickness T1 and the center thickness T2, of the formed type flat panel 20 are tailored as a function of the diagonal length D and the radius of curvature R.
That is, in order to fabricate a formed type flat panel formed of tinted glass, where the diagonal length D is equal to or greater than 700 mm and the radius of curvature R of the external surface 12b of the faceplate 12 is equal to or greater than 10,000 mm, the periphery thickness T1, the center thickness T2 and the wedge rate (T1/T2) need to satisfy the following Eqs. 1–3:
0.03D−5≦T1≦0.039D+15/(D0.5−1.5)+2.54 Eq. 1
0.0185D−6.5≦T2≦0.0204D Eq. 2
1.3≦T1/T2≦2.1 Eq. 3
A tinted 32 inch formed type flat panel (made of tinted glass) (panel 1), which satisfies Eqs. 1 to 3, was made and tested under the UL impact test (or UL standard for implosion resistance). The results are listed in Tables 1 and 2. In addition, the tables further include results for comparative formed type flat panels (panels C1 to C3) made of clear glass.
As indicated in Tables 1 and 2, the formed type flat panel (panel 1), which satisfies Eqs. 1 to 3, also satisfies both of the UL standard for implosion resistance and the BU standard. However, the comparative formed type flat panels (panels C1 to C3), which do not satisfy at least one of Eqs. 1 to 3, do not satisfy the BU standard.
Further, in order to fabricate a formed type flat panel formed of tinted glass, where the diagonal length D is equal to or greater than 665 mm but less than 700 mm, and the radius of curvature R of the external surface 12b of the faceplate 12 is equal to or greater than 10,000 mm, the periphery thickness T1, the center thickness T2 and the wedge rate (T1/T2) need to satisfy the following Eqs. 4–6:
0.03D−5≦T1≦0.039D+15/(D0.5−1.5)+2.54 Eq. 4
0.0185D−6.5≦T2≦0.0204D Eq. 5
1.3≦T1/T2≦1.97 Eq. 6
Two tinted 29 inch formed type flat panels (made of tinted glass) (panels 2 and 3), which satisfy Eqs. 4 to 6 were made and tested under the UL impact test (or UL standard for implosion resistance). The results are listed in Tables 3 and 4. In addition, the tables further include results for comparative formed type flat panels (panels C4 to C6) made of clear glass.
As indicated in Tables 3 and 4, the formed type flat panels (panels 2 and 3), which satisfy Eqs. 4 to 6, also satisfy both of the UL standard for implosion resistance and the BU standard. However, the comparative formed type flat panels (panels C4 to C6), which do not satisfy at least one of Eqs. 4 to 6, do not satisfy the BU standard.
Further, in order to fabricate a formed type flat panel formed of tinted glass, where the diagonal length D is equal to or greater than 550 mm but less than 665 mm, and the radius of curvature R of the external surface 12b of the faceplate 12 is equal to or greater than 10,000 mm, the periphery thickness T1, the center thickness T2 and the wedge rate (T1/T2) need to satisfy the following Eqs. 7–9:
0.03D−5≦T1≦0.039D+15/(D0.5−1.5)+2.54 Eq. 7
0.0185D−6.5≦T2≦0.0204D Eq. 8
1.3≦T1/T2≦2.1 Eq. 9
Tinted formed type flat panels (made of tinted glass) (panels 4 and 6), which satisfy Eqs. 7 to 9 were made and tested under the UL impact test (or UL standard for implosion resistance). The results are listed in Tables 5 and 6. In addition, the tables further include results for comparative formed type flat panels (panels C7 to C11) made of clear glass.
As indicated in Tables 5 and 6, the formed type flat panels (panels 4 and 6), which satisfy Eqs. 7 to 9, also satisfy both of the UL standard for implosion resistance and the BU standard. However, the comparative formed type flat panels (panels C7 to C11), which do not satisfy at least one of Eqs. 4 to 6, do not satisfy the BU standard.
Further, in order to fabricate a formed type flat panel formed of tinted glass, where the diagonal length D is equal to or greater than 500 mm but less than 550 mm, and the radius of curvature R of the external surface 12b of the faceplate 12 is equal to or greater than 10,000 mm, the periphery thickness T1, the center thickness T2 and the wedge rate (T1/T2) need to satisfy the following Eqs. 10–12:
0.035D−((0.003D)2−2.54)−5≦T1≦0.07D−((0.004D)4−2.54)+1.2 Eq. 10
0.031D−(0.004D)2−5.5≦T2≦0.056D−(0.007D)2−0.254 Eq. 11
1.3≦T1/T2≦2.1 Eq. 12
A tinted 21 inch formed type flat panel (made of tinted glass) (panel 7), which satisfies Eqs. 10 to 12 was made and tested under the UL impact test (or UL standard for implosion resistance). The results are listed in Tables 7 and 8. In addition, the tables further include results for comparative formed type flat panels (panels C12 to C13) made of clear glass.
As indicated in Tables 7 and 8, the formed type flat panel (panel 7), which satisfies Eqs. 10 to 12, also satisfies both of the UL standard for implosion resistance and the BU standard. However, the comparative formed type flat panels (panels C12 to C13), which do not satisfy at least one of Eqs. 4 to 6, do not satisfy the BU standard.
Further, in order to fabricate a formed type flat panel formed of tinted glass, where the diagonal length D is less than 500 mm, and the radius of curvature R of the external surface 12b of the faceplate 12 is equal to or greater than 10,000 mm, the periphery thickness T1, the center thickness T2 and the wedge rate (T1/T2) need to satisfy the following Eqs. 13–15:
0.035D−((0.003D)2−2.54)−5≦T1≦0.07D−((0.004D)4−2.54) Eq. 13
0.031D−(0.004D)2−3.5≦T2≦0.056D−(0.007D)2+1.5 Eq. 14
1.3≦T1/T2≦2.1 Eq. 15
Tinted formed type flat panels (made of tinted glass) (panels 8 and 12), which satisfy Eqs. 13 to 15, were made and tested under the UL impact test (or UL standard for implosion resistance). The results are listed in Tables 9 and 10. In addition, the tables further include results for comparative formed type flat panels (panels C14 to C16) made of clear glass.
As indicated in Tables 9 and 10, the formed type flat panels (panels 8 to 12), which satisfy Eqs. 13 to 15, also satisfies both of the UL standard for implosion resistance and the BU standard. However, the comparative formed type flat panels (panels C14 to C16), which do not satisfy at least one of Eqs. 13 to 15, do not satisfy the BU standard.
As described above, the tinted formed type flat panel in accordance with the preferred embodiment of the present invention eliminates a need for the coating process required in manufacturing a formed type flat panel made of clear glass and the tank color conversion loss, inevitably lowering the manufacturing costs.
While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10-2002-0011017 | Feb 2002 | KR | national |
| 10-2003-0009699 | Feb 2003 | KR | national |
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|---|---|---|---|
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| 6566802 | Jeong | May 2003 | B1 |
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| 6639345 | Inoue et al. | Oct 2003 | B1 |
| 6677702 | Kim et al. | Jan 2004 | B1 |
| 6680567 | Sugawara et al. | Jan 2004 | B1 |
| Number | Date | Country | |
|---|---|---|---|
| 20030164669 A1 | Sep 2003 | US |
