Glass panel for a cathode ray tube

Abstract

A glass panel for a cathode ray tube including a substantially rectangular face portion and a skirt portion. Further constituting a side wall of the face portion, a compressive stress layer having a thickness of at least {fraction (1/10)} of the thickness of the face portion, is formed on each of the inner and outer surfaces of a useful screen area of the face portion, so as to satisfy 0.4≦σ di /σ ci ≦1.0, where σ ci is the compressive stress on the inner surface at the center of the useful screen area, and σ di is the compressive stress on the inner surface in the vicinity of ends of diagonal axial lines of the useful screen area.

What is claimed is:  
     
       1. A glass panel for a cathode ray tube comprising: 
       a substantially rectangular face portion having a radius of curvature which satisfies the equation:  
       
         
               0 ≦z≦r   2 /(   1 × 10     4 ),  
         
       
         where r is a distance  ( mm )  on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance  ( mm )  from the end point to a tangential plane at the center of the useful screen area ; and  
       a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer having a thickness of at least {fraction (1/10)} of a thickness of the face portion, and which satisfies a compressive stress ratio:  
       
         
           0.4≦σ di /σ ci ≦1.0,  
         
       
       where σ ci  is a compressive stress on the inner surface at a center of the useful screen area, and σ di  is a compressive stress on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area. 
     
     
       2. The glass panel for a cathode ray tube according to  claim 1 , wherein the compressive stress σ di  is within a range of 5.0≦|σ di |≦25.0 (MPa). 
     
     
       3. The glass panel for a cathode ray tube according to  claim 1 , wherein the face portion has a radius of curvature which satisfies the equation: 
       
         
           0≦z≦r 2 /(1×10 4 ),  
         
       
       where r is a distance (mm) on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance (mm) from the end point to a tangential plane at the center of the useful screen area. 
     
     
       4. The glass panel for a cathode ray tube according to  claim 1 , wherein the compressive stress ratio satisfies the equation: 0.5≦σ di /σ ci ≦0.8. 
     
     
       5. The glass panel for a cathode ray tube according to  claim 2 , wherein the compressive stress σ di  is within a range of 6.0≦|σ di ≦20.0 (MPa). 
     
     
       6. The glass panel for a cathode ray tube according to claim  3   1 , wherein the radius of curvature satisfies the equation: 0≦z≦r 2 /(6×10 4 ). 
     
     
       7. A glass panel for a cathode ray tube comprising: 
       a substantially rectangular face portion; and  
       a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer which satisfies a compressive stress ratio:  
       
         
           0.4≦σ di /σ ci ≦1.0  0.5≦σ di /σ ci   ≦ 0 . 8   ,  
         
       
       where σ ci  is a compressive stress on the inner surface at a center of the useful screen area, and σ di  is a compressive stress on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area. 
     
     
       8. A glass panel for a cathode ray tube comprising: 
       a substantially rectangular face portion having a radius of curvature which satisfies the equation:  
       
         
               0 ≦z≦r   2 /(   1 × 10     4 ),  
         
       
         where r is a distance  ( mm )  on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance  ( mm )  from the end point to a tangential plane at the center of the useful screen area ; and  
       a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer having a thickness of at least {fraction (1/10)} of a thickness of the face portion, and which satisfies the compressive stress ratio:  
       
         
           0.4≦σ di /σ do ≦1.4,  
         
       
       where σ di  is a compressive stress on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area, and σ do  is a compressive stress on the outer surface in the vicinity of ends of diagonal axial lines of the useful screen area. 
     
     
       9. The glass panel for a cathode ray tube according to  claim 8 , wherein the compressive stress σ di  is within a range of 5.0≦|σ di |≦25.0 (MPa). 
     
     
       10. The glass panel for a cathode ray tube according to  claim 8 , wherein the face portion has a radius of curvature which satisfies the equation: 
       
         
           0≦z≦r 2 /(1×10 4 ),  
         
       
       where r is a distance (mm) on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance (mm) from the end point to a tangential plane at the center of the useful screen area.  
     
     
       11. The glass panel for a cathode ray tube according to  claim 8 , wherein the compressive stress ratio satisfies the equation: 0.5≦σ di /σ do ≦1.0. 
     
     
       12. The glass panel for a cathode ray tube according to  claim 9 , wherein the compressive stress σ di  is within a range of 6.0≦|σ di |≦20.0 (MPa). 
     
     
       13. The glass panel for a cathode ray tube according to claim  10   8 , wherein the radius of curvature satisfies the equation: 0≦z≦r 2 /(6×10 4 ). 
     
     
       14. A glass panel for a cathode ray tube comprising: 
       
         a substantially rectangular face portion having a radius of curvature which satisfies the equation:  
       
       
         
               0 ≦z≦r   2 /(   1 × 10     4 ),  
         
       
         where r is a distance  ( mm )  on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance  ( mm )  from the end point to a tangential plane at the center of the useful screen area; and    
       
         a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer having a thickness of at least {fraction ( 1 / 10 )} of a thickness of the face portion and wherein the compressive stress, σ 
         di 
         , on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area is within the range of  5 . 0 ≦|σ 
         di 
         |≦ 25 . 0  MPa and is less than the stress on the inner surface, σ 
         ci 
         , in the center portion of the panel. 
       
     
     
       15. The glass panel for a cathode ray tube according to  claim 14 , wherein the radius of curvature satisfies the equation:  0 ≦z≦r 2 /(   6 × 10     4 ). 
     
     
       16. The glass panel for a cathode ray tube according to  claim 14 , wherein the compressive stress σ di    is within a range of  6 . 0 ≦|σ   di   |≦ 20 . 0   ( MPa ). 
     
     
       17. A glass panel for a cathode ray tube comprising: 
       
         a substantially rectangular face portion having a radius of curvature which satisfies the equation:  
       
       
         
               0 ≦z≦r   2 /(   1 × 10     4 ),  
         
       
         where r is a distance  ( mm )  on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance  ( mm )  from the end point to a tangential plane at the center of the useful screen area; and    
       
         a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer which satisfies a compressive stress ratio:  
       
       
         
               0 . 4 ≦σ   di /σ ci   ≦ 1 . 0 ,    
         
       
         where σ   ci    is a compressive stress on the inner surface at a center of the useful screen area, and σ   di    is a compressive stress on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area.   
     
     
       18. The glass panel for a cathode ray tube according to  claim 17 , wherein the radius of curvature satisfies the equation:  0 ≦z≦r 2 /(   6 × 10     4 ). 
     
     
       19. The glass panel for a cathode ray tube according to  claim 17 , wherein the compressive stress σ di    is within a range of  6 . 0 ≦|σ   di   |≦ 20 . 0   ( MPa ). 
     
     
       20. A glass panel for a cathode ray tube comprising: 
       
         a substantially rectangular face portion having a radius of curvature which satisfies the equation:  
       
       
         
               0 ≦z≦r   2 /(   1 × 10     4 ),  
         
       
         where r is a distance  ( mm )  on a diagonal axial line of the outer surface of the face portion of the useful screen area from a center axis to an end point of the useful screen area, and z is a distance  ( mm )  from the end point to a tangential plane at the center of the useful screen area; and    
       
         a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer which satisfies the compressive stress ratio:  
       
       
         
               0 . 4 ≦σ   di /σ ci   ≦ 1 . 4     
         
       
         where σ   di    is a compressive stress on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area, and σ   do    is a compressive stress on the outer surface in the vicinity of ends of diagonal axial lines of the useful screen area.   
     
     
       21. The glass panel for a cathode ray tube according to  claim 20 , wherein the radius of curvature satisfies the equation:  0 ≦z≦r 2 /(   6 × 10     4 ). 
     
     
       22. The glass panel for a cathode ray tube according to  claim 20 , wherein the compressive stress σ di    is within a range of  6 . 0 ≦|σ   di   |≦ 20 . 0   ( MPa ). 
     
     
       23. A glass panel for a cathode ray tube comprising: 
       
         a substantially rectangular face portion; and  
       
       
         a skirt portion forming a side wall of the face portion, wherein inner and outer surfaces of a useful screen area of the face portion include a compressive stress layer having a thickness of at least {fraction ( 1 / 10 )} of a thickness of the face portion, and which satisfies a compressive stress ratio:  
       
       
         
               0 . 5 ≦σ   di /σ ci   ≦ 0 . 8 ,    
         
       
         where σ   ci    is a compressive stress on the inner surface at a center of the useful screen area, and σ   di    is a compressive stress on the inner surface in a vicinity of ends of diagonal axial lines of the useful screen area.   
     
     
       24. The glass panel for a cathode ray tube according to  claim 23 , wherein the radius of curvature satisfies the equation:  0 ≦z≦r 2 /(   6 × 10     4 ). 
     
     
       25. The glass panel for a cathode ray tube according to  claim 24 , wherein the compressive stress σ di    is within a range of  6 . 0 ≦|σ   di   |≦ 20 . 0   ( MPa ). 
     
     
       26. The glass panel for a cathode ray tube according to  claim 1 , wherein the stresses in said rectangular face portion satisfy the ratio: 
       
         
               0 . 4 ≦σ   di /σ do   ≦ 1 . 4     
         
       
       
         wherein σ 
         do  
         is a compressive stress on the outer surface in the vicinity of ends of diagonal axial lines of the useful screen area. 
       
     
     
       27. The glass panel for a cathode ray tube according to  claim 26 , wherein the compressive stress σ di    is within the range of  6 . 0 ≦σ   di   ≦ 20 . 0  MPa.