Formed type flat panel for use in a cathode ray tube

1. A formed type flat panel made of tinted glass, comprising:

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

wherein

T 1 is a periphery thickness of the faceplate, and

T 2 is a center thickness of the faceplate.

2. The formed type flat panel of claim 1 , wherein the tinted glass has a light transmittance of about 52.5±5% when having a thickness of about 11.43 mm.

3. A formed type flat panel made of tinted glass, comprising:

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

wherein

T 1 is a periphery thickness of the faceplate, and

T 2 is a center thickness of the faceplate.

4. The formed type flat panel of claim 3 , wherein the tinted glass has a light transmittance of about 52.5±5% when having a thickness of about 11.43 mm.