Abstract:
The present invention provides a formed type flat panel made of tinted glass, which is capable of satisfying the UL standard for implosion resistance thereof. The formed type flat panel of the present invention includes a substantially rectangular faceplate having an substantially flat external surface and a curved inner surface; a skirt portion extending backward from a periphery of the faceplate; a corner portion joining the faceplate and the skirt portion. The faceplate has a specially tailored thickness distribution so at to accomplish aforementioned capability.

Description:
FIELD OF THE INVENTION  
         [0001]    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.  
         BACKGROUND OF THE INVENTION  
         [0002]    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.  
           [0003]    Referring to FIG. 1, there is shown a schematic cross sectional view of a formed type flat panel for use in CRTs. The formed type flat panel  10  has a faceplate portion  12 , a skirt portion  14  extending backwards from a periphery of the faceplate portion  12  and connected to a funnel (not shown), and a corner portion  16  (or blend round portion) integrally joining the periphery portion of the faceplate portion  12  with the skirt portion  14 . The faceplate portion  12  is provided with a virtually flat external surface  12   b  and an inner surface  12   a  possessing a curvature considerably greater than that of the external surface  12   b.  And fixed on the skirt portion  14  by stud pins is a formed mask (not shown).  
           [0004]    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.  
           [0005]    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.  
           [0006]    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.  
           [0007]    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.  
           [0008]    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&#39; 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.  
         SUMMARY OF THE INVENTION  
         [0009]    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.  
           [0010]    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 R 1 , R 1  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  
           0.03 D− 5≦ T   1 ≦0.039 D+ 15/( D   0.5 −1.5)+2.54 
           0.0185 D− 6.5≦ T   2 ≦0.0204 D   
           1.3≦ T   1   /T   2 ≦2.1 
           [0011]    wherein T 1  is a periphery thickness of the faceplate, and T 2  is a center thickness of the faceplate.  
           [0012]    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 R 1 , R 1  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  
           0.03 D− 5≦ T   1 ≦0.039 D+ 15/( D   0.5 −1.5)+2.54 
           0.0185 D− 6.5≦ T   2 ≦0.0204 D   
           1.3≦ T   1   /T   2 ≦1.97 
           [0013]    wherein T 1  is a periphery thickness of the faceplate, and T 2  is a center thickness of the faceplate.  
           [0014]    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 R 1 , R 1  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  
           0.03 D −((0.003 D ) 2 −2.54)−5≦ T   1 ≦0.07 D− ((0.004 D ) 4 −2.54)+1.2 
           0.031 D −(0.004 D ) 2   ≦T   2 ≦0.056 D −(0.007 D ) 2 −0.254 
           1.3 ≦T   1   /T   2 ≦2.1 
           [0015]    wherein T 1  is a periphery thickness of the faceplate, and T 2  is a center thickness of the faceplate.  
           [0016]    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 R 1 , R 1  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  
           0.035 D −((0.003 D ) 2 −2.54)−5 ≦T   1 ≦0.07 D −((0.004 D )4−2.54) 
           [0017]    0.031 D −(0.004 D ) 2 −3.5 ≦T   2 ≦0.056 D −(0.007 D ) 2 +1.5 
           1.3 ≦T   1   /T   2 ≦2.1  
           [0018]    wherein T 1  is a periphery thickness of the faceplate, and T 2  is a center thickness of the faceplate.  
       
    
    
     Brief Description of the Drawings  
       [0019]    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:  
         [0020]    [0020]FIG. 1 illustrates a schematic cross sectional view of a formed type flat panel for use in CRTs;  
         [0021]    [0021]FIG. 2 presents a schematic top view of the formed type flat panel  20  in accordance with the preferred embodiment of the present invention; and  
         [0022]    [0022]FIG. 3 depicts a cross sectional view taken along the line A-A in FIG. 2. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0023]    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.  
         [0024]    Referring to FIG. 2, there is schematically illustrated a top view of the formed type flat panel  20  in accordance with the preferred embodiment of the present invention. As shown in FIG. 2, the contour of the formed type flat panel  20  is of an approximate rectangular shape having a pair of nearly parallel long sides  18   a,    18   b  and a pair of substantially parallel short sides  20   a,    20   b.  And the formed type flat panel  20  includes a faceplate  12 , which has a central portion  24  serving as an effective picture plane  22 , a periphery portion  26  around the effective picture plane  22 , an external surface  12   b  (shown in FIG. 3) having a radius of curvature R and a curved inner surface  12   a  (shown in FIG. 3) having a radius of curvature R 1 , wherein R is considerably greater than R 1 , so that the external surface  12   b  is substantially flat. And the diagonal length of the effective picture plane  22  is designated as D.  
         [0025]    Referring to FIG. 3, there is schematically described a cross sectional view taken along the line A-A in FIG. 2. The parts corresponding to those of the formed type flat panel  10  shown in FIG. 1 will be designated with the like reference numerals, and description thereof will be omitted for simplicity. As shown in FIG. 3, an inner surface  16   a  of the corner portion  16  forms an arc having a point of tangency with the inner surface  12   a  of the faceplate  12 .  
         [0026]    The thickness of the faceplate  12  at the point of tangency is referred to as a faceplate periphery thickness T 1 . In other words, T 1  is a thickness of the faceplate  12  at the point where the inner surface  12   a  having the radius of curvature R 1  meets the inner surface  16   a  having a radius of curvature R 2 . 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 T 2 .  
         [0027]    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.  
         [0028]    In accordance with the present invention, a formed type flat panel can be made of the tinted glass while satisfying tube makers&#39; standard for brightness uniformity (BU) and the UL standards for implosion resistance, in case dimensions, i.e., the periphery thickness T 1  and the center thickness T 2 , of the formed type flat panel  20  are tailored as a function of the diagonal length D and the radius of curvature R.  
         [0029]    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  12   b  of the faceplate  12  is equal to or greater than 10,000 mm, the periphery thickness T 1 , the center thickness T 2  and the wedge rate (T 1 /T 2 ) need to satisfy the following Eqs. 1-3:  
         0.03 D− 5 ≦T   1 ≦0.039 D +15/( D   0.5 −1.5)+2.54  Eq. 1 
         0.0185 D− 6.5 ≦T   2 ≦0.0204 D   Eq. 2 
         1.3 ≦T   1 /T 2 ≦2.1  Eq. 3 
       EXAMPLE 1  
       [0030]    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.  
                                                             TABLE 1                                       Panel                   Size       Dimension (mm)            PANEL   (Inch)   R (mm)   D   T 1     T 2     T 1 /T 2                 panel 1   32    50,000   760   23.25   13.00   1.79       panel C1   32   100,000   760   31.69   13.00   2.44       panel C2   32   100,000   760   32.69   14.00   2.34       panel C3   32    50,000   760   30.47   12.50   2.44                  
 
         [0031]    [0031]                                                                                             TABLE 2                                       T 1  Range   T 2  Range   T 1 /T 2  Range   Dimension                   (mm)   (mm)   (mm)   Test   Implosion   BU            PANEL   Min.   Max.   Min.   Max.   Min.   Max.   T 1     T 2     T 1 /T 2     Test   Test               panel 1   17.80   32.76   7.56   15.50   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel   17.80   32.76   7.56   15.50   1.30   2.10   ◯   ◯   X   ◯   X       C1       panel   17.80   32.76   7.56   15.50   1.30   2.10   ◯   ◯   X   ◯   X       C2       panel   17.80   32.76   7.56   15.50   1.30   2.10   ◯   ◯   X   ◯   X       C3                    
         [0032]    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.  
         [0033]    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  12   b  of the faceplate  12  is equal to or greater than 10,000 mm, the periphery thickness T 1 , the center thickness T 2  and the wedge rate (T 1 /T 2 ) need to satisfy the following Eqs. 4-6:  
         0.03 D −5 ≦T   1 ≦0.039 D +15/( D   0.5 −1.5)+2.54  Eq. 4 
         0.0185 D −6.5 ≦T   2 ≦0.0204 D   Eq. 5 
         1.3 ≦T   1   /T   2 ≦1.97  Eq. 6  
       EXAMPLE 2  
       [0034]    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.  
                                                             TABLE 3                                       Panel                   Size       Dimension (mm)            PANEL   (Inch)   R (mm)   D   T 1     T 2     T 1 /T 2                 panel 2   29   100,000   676   23.05   12.50   1.84       panel 3   29    50,000   676   23.74   12.50   1.90       panel C4   29   100,000   676   27.46   12.50   2.20       panel C5   29   100,000   676   29.46   14.50   2.03       panel C6   29    32,470   678   24.93   12.50   1.99                  
 
         [0035]    [0035]                                                                                             TABLE 4                                       T 1  Range   T 2  Range   T 1 /T 2  Range   Dimension                   (mm)   (mm)   (mm)   Test   Implosion   BU            PANEL   Min.   Max.   Min.   Max.   Min.   Max.   T 1     T 2     T 1 /T 2     Test   Test               panel 2   15.28   29.52   6.01   13.79   1.30   1.97   ◯   ◯   ◯   ◯   ◯       panel 3   15.28   29.52   6.01   13.79   1.30   1.97   ◯   ◯   ◯   ◯   ◯       panel   15.28   29.52   6.01   13.79   1.30   1.97   ◯   ◯   X   ◯   X       C4       panel   15.28   29.52   6.01   13.79   1.30   1.97   ◯   X   X   ◯   X       C5       panel   15.28   29.52   6.04   13.83   1.30   1.97   ◯   ◯   X   ◯   X       C6                    
         [0036]    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.  
         [0037]    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  12   b  of the faceplate  12  is equal to or greater than 10,000 mm, the periphery thickness T 1 , the center thickness T 2  and the wedge rate (T 1 /T 2 ) need to satisfy the following Eqs. 7-9:  
         0.03 D− 5 ≦T   1 ≦0.039 D+ 15/( D   0.5 −1.5)+2.54  Eq. 7 
         0.0185 D− 6.5 ≦T   2 ≦0.0204 D   Eq. 8 
         1.3 ≦T   1   /T   2 ≦2.1  Eq. 9  
       EXAMPLE 3  
       [0038]    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.  
                                                                                           TABLE 5                                       Panel                   Size       Dimension (mm)            PANEL   (Inch)   R (mm)   D   T 1     T 2     T 1 /T 2                      panel 4   25    30,000   590   23.66   12.00   1.97       panel 5   25    50,000   590   24.28   12.00   2.02       panel 6   28   100,000   660   22.93   12.50   1.83       panel C7   25    30,000   590   25.16   13.50   1.86       panel C8   25   100,000   590   25.71   13.00   1.98       panel C9   25    53,570   598.9   24.57   12.50   1.97       panel C10   28   100,000   660   28.12   13.50   2.08       panel C11   28   100,000   660   23.93   13.50   1.77                  
 
         [0039]    [0039]                                                                                             TABLE 6                                       T 1  Range   T 2  Range   T 1 /T 2  Range   Dimension                   (mm)   (mm)   (mm)   Test   Implosion   BU            PANEL   Min.   Max.   Min.   Max.   Min.   Max.   T 1     T 2     T 1 /T 2     Test   Test               panel 4   12.70   26.21   4.42   12.04   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel 5   12.70   26.21   4.42   12.04   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel 6   14.80   28.90   5.71   13.46   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel   12.70   26.21   4.42   12.04   1.30   2.10   ◯   X   ◯   ◯   X       C7       panel   12.70   26.21   4.42   12.04   1.30   2.10   ◯   X   ◯   ◯   X       C8       panel   12.97   26.55   4.58   12.22   1.30   2.10   ◯   X   ◯   ◯   X       C9       panel   14.80   28.90   5.71   13.46   1.30   2.10   ◯   X   ◯   ◯   X       C10       panel   14.80   28.90   5.71   13.46   1.30   2.10   ◯   X   ◯   ◯   X       C11                    
         [0040]    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.  
         [0041]    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  12   b  of the faceplate  12  is equal to or greater than 10,000 mm, the periphery thickness T 1 , the center thickness T 2  and the wedge rate (T 1 /T 2 ) need to satisfy the following Eqs. 10-12:  
         0.035 D −((0.003 D ) 2 −2.54)−5 ≦T   1 ≦0.07 D−(( 0.004 D ) 4 −2.54)+1.2  Eq. 10 
         0.031 D −(0.004 D ) 2 −5.5 ≦T   2 ≦0.056 D −(0.007 D ) 2 −0.254  Eq. 11 
         1.3 ≦T   1   /T   2 ≦2.1  Eq. 12  
       EXAMPLE 4  
       [0042]    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.  
                                                                                           TABLE 7                                       Panel                   Size       Dimension (mm)            PANEL   (Inch)   R (mm)   D   T 1     T 2     T 1 /T 2                      panel 7   21    50,000   508   21.08   11.00   1.92       panel C12   21   100,000   505.3   23.32   12.00   1.94       panel C13   21   100,000   508   23.30   13.00   1.79                  
 
         [0043]    [0043]                                                                                             TABLE 8                                       T 1  Range   T 2  Range   T 1 /T 2  Range   Dimension                   (mm)   (mm)   (mm)   Test   Implosion   BU            PANEL   Min.   Max.   Min.   Max.   Min.   Max.   T 1     T 2     T 1 /T 2     Test   Test               panel 7   13.00   22.25   6.12   15.55   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel   12.93   22.42   6.08   15.53   1.30   2.10   X   ◯   ◯   ◯   X       C12       panel   13.00   22.25   6.12   15.55   1.30   2.10   X   ◯   ◯   ◯   X       C13                    
         [0044]    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.  
         [0045]    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  12   b  of the faceplate  12  is equal to or greater than 10,000 mm, the periphery thickness T 1 , the center thickness T 2  and the wedge rate (T 1 /T 2 ) need to satisfy the following Eqs. 13-15:  
         0.035 D −((0.003 D ) 2 −2.54)−5 ≦T   1 ≦0.07 D −((0.004 D ) 4 −2.54)  Eq. 13 
         0.031 D −(0.004 D ) 2 −3.5 ≦T   2 ≦0.056 D −(0.007 D ) 2 +1.5  Eq. 14 
         1.3 ≦T   1   /T   2 ≦2.1  Eq. 15 
       EXAMPLE 5  
       [0046]    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.  
                                                                                           TABLE 9                                       Panel                   Size       Dimension (mm)            PANEL   (Inch)   R (mm)   D   T 1     T 2     T 1 /T 2                      panel 8   10   57,260   203.8   15.22   8.80   1.73       panel 9   15   50,000   355.6   17.69   10.00   1.77       panel 10   15   50,000   355.6   17.19   9.50   1.81       panel 11   17   57,260   406.7   20.38   11.00   1.85       panel 12   17   57,260   406.7   21.56   10.50   2.05       panel C14   17   57,260   406.7   23.70   11.00   2.15       panel C15   17   57,260   406.7   23.20   10.50   2.21       panel C16   19   57,260   457.2   25.60   11.00   2.33                  
 
         [0047]    [0047]                                                                                                                                               TABLE 10                                       T 1  Range   T 2  Range   T 1 /T 2  Range   Dimension                   (mm)   (mm)   (mm)   Test   Implosion   BU            PANEL   Min.   Max.   Min.   Max.   Min.   Max.   T 1     T 2     T 1 /T 2     Test   Test                    panel 8   5.14   17.97   2.80   11.81   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel 9   8.85   23.34   5.50   15.22   1.30   2.10   ◯   ◯   ◯   ◯   ◯       panel   8.85   23.34   5.50   15.22   1.30   2.10   ◯   ◯   ◯   ◯   ◯       10       panel   10.29   24.01   6.46   16.17   1.30   2.10   ◯   ◯   ◯   ◯   ◯       11       panel   10.29   24.01   6.46   16.17   1.30   2.10   ◯   ◯   ◯   ◯   ◯       12       panel   10.29   24.01   6.46   16.17   1.30   2.10   ◯   ◯   X   ◯   X       C14       panel   10.29   24.01   6.46   16.17   1.30   2.10   ◯   ◯   X   ◯   X       C15       panel   11.66   23.36   7.33   16.86   1.30   2.10   X   ◯   X   ◯   X       C16                    
         [0048]    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.  
         [0049]    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.  
         [0050]    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.