Heat ray-absorbing glass plate and method for producing same

1. A heat-absorbing glass plate comprising iron, tin, selenium, cobalt and sulfur, wherein

the mass ratio of divalent iron as calculated as Fe 2 O 3 to total iron as calculated as Fe 2 O 3 is at least 55%,

the content of Se as represented by mass % based on Se is from 0.0002 to 0.0010%,

the content of total cobalt as calculated as CoO is, as represented by mass % based on oxides, from 0.0002 to 0.00200%,

the content of total tin as calculated as SnO 2 is, as represented by mass % based on oxides, at least 0.02%,

the ratio Tv/Te of the visible light transmittance Tv (by illuminant A, 2° visual field) as defined in JIS R3106 (1998) calculated as 4 mm thickness of the glass plate to the solar transmittance Te as defined in JIS R3106 (1998), calculated as 4 mm thickness of the glass plate, is at least 1.5,

the visible light transmittance Tv (by illuminant A, 2° visual field) is higher than 65% as defined in JIS R3106 (1998) calculated as 4 mm thickness of the glass plate, and

the excitation purity Pe is at most 7% as defined in JIS Z8701 (1999) calculated as 4 mm thickness of the glass plate.

2. The heat-absorbing glass plate according to claim 1 , which comprises soda lime silica glass comprising, as represented by mass % based on the following components:

SiO 2 : 65 to 75%,

Al 2 O 3 : more than 3% and at most 6%,

MgO: 0% to less than 2%,

CaO: 7 to 10%,

Na 2 O: 5 to 18%,

K 2 O: 0 to 5%,

total iron as calculated as Fe 2 O 3 : 0.3 to 0.9%,

total tin as calculated as SnO 2 : 0.02 to 0.3%

Se: 0.0002 to 0.0010%

CoO: 0.0002 to 0.0020% and

total sulfur as calculated as SO 3 : 0.002 to 0.1%.

3. The heat-absorbing glass plate according to claim 1 , wherein the content of total sulfur as calculated as SO 3 as represented by mass % based on oxides is from 0.002 to 0.1%.

4. The heat-absorbing glass plate according to claim 1 , wherein the content of total sulfur as calculated as SO 3 as represented by mass % based on oxides is at least 0.005% and less than 0.02%.

5. The heat-absorbing glass plate according to claim 1 , wherein the content of total tin as calculated as SnO 2 is, as represented by mass % based on oxides, at least 0.05%.

6. The heat-absorbing glass plate according to claim 1 , wherein the content of total tin as calculated as SnO 2 is, as represented by mass % based on oxides, at least 0.09%.

7. The heat-absorbing glass plate according to claim 1 , wherein the mass ratio (SnO 2 /SO 3 ) of the content of total tin as calculated as SnO 2 to the content of total sulfur as calculated as SO 3 is from 0.2 to 105.

8. The heat-absorbing glass plate according to claim 1 , wherein the content of total iron as calculate as Fe 2 O 3 as represented by mass % based on oxides is from 0.01 to 1.0%.

9. The heat-absorbing glass plate according to claim 1 , wherein the MgO content as represented by mass % based on oxides is at most 3.0%.

10. The heat-absorbing glass plate according to claim 1 , wherein the transmittance at a wavelength of 1,500 nm is at most 30% calculated as 4 mm thickness of the glass plate.

11. The heat-absorbing glass plate according to claim 1 , which provides a transmitted light having a dominant wavelength Dw of at most 510 nm as defined in JIS Z8701 (1999) calculated as 4 mm thickness of the glass plate.

12. The heat-absorbing glass plate according to claim 1 , wherein the solar transmittance Te is at most 50% as defined in JIS R3106 (1998) calculated as 4 mm thickness of the glass plate.

13. The heat-absorbing glass plate according to claim 1 , wherein β-OH is at least 0.15 mm −1 .

14. A process for producing a heat-absorbing glass plate, which comprises melting a glass raw material, followed by forming to produce soda lime silica glass, wherein the glass after the forming is the heat-absorbing glass plate as defined in claim 1 .