Near infrared cutoff filter glass
To provide a near infrared cutoff filter glass which is excellent in optical properties such that the transmittance of light in the visible range is high and the transmittance of near infrared light is low. A near infrared cutoff filter glass comprising P, F, O, Cu and Ce, wherein by cation %, from 0.1 to 15% of Cu 2+ is contained, and the ratio of Cu 2+ to Ce 4+ (Cu 2+ /Ce 4+ ) is from 3.5 to 15.
1. A near infrared cutoff filter glass comprising, wherein by cation %,
P 5+ : from 30 to 50%,
Al 3+ : from 5 to 20%,
R + : from 20 to 40% (wherein R + is the total amount of Li + , Na + and K + ),
R′ 2+ : from 5 to less than 12% (wherein R′ 2+ is the total amount of Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ and Zn 2+ ),
Cu 2+ : from 0.1 to 15%,
Sb 3+ : from 0 to 1%, and
Ce 4+ : from 0.01 to 4%,
and as represented by anion %,
O 2− : from 30 to 90% and
F − : from 10 to 70%; and
the ratio of Cu 2+ to Ce 4+ (Cu 2+ /Ce 4+ ) is from 3.5 to 15.
2. The near infrared cutoff filter glass according to claim 1 , wherein by cation %, from 0.01 to 3% of Ce 4+ is contained.
3. The near infrared cutoff filter glass according to claim 1 , wherein the numerical value obtained by dividing the absorption coefficient at a wavelength of 400 nm by the absorption coefficient at a wavelength of 800 nm is in a range of from 0.00001 to 0.03.
4. The near infrared cutoff filter glass according to claim 1 , wherein Cu 2+ is from 0.2 to 10% by cation %.
5. The near infrared cutoff filter glass according to claim 1 , wherein the ratio of Cu 2+ to Ce 4+ (Cu 2+ /Ce 4+ ) is from 5 to 14.
6. The near infrared cutoff filter glass according to claim 1 , wherein the ratio of Cu 2+ to Ce 4+ (Cu 2+ /Ce 4+ ) is from 6 to 14.
7. The near infrared cutoff filter glass according to claim 1 , wherein Ce 4+ is from 0.05 to 3% by cation %.
8. The near infrared cutoff filter glass according to claim 1 , wherein P 5+ is from 32 to 48% by cation %.
9. The near infrared cutoff filter glass according to claim 1 , wherein Al 3+ is from 6 to 18% by cation %.
10. The near infrared cutoff filter glass according to claim 1 , wherein R + is from 22 to 38% by cation % (wherein R + is the total amount of Li + , Na + and K + ).
11. The near infrared cutoff filter glass according to claim 1 , wherein R + is at least Li + and Li + is from 5 to 40% by cation %.
12. The near infrared cutoff filter glass according to claim 1 , wherein R + is at least Na + and Na + is from 5 to 40% by cation %.
13. The near infrared cutoff filter glass according to claim 1 , wherein R + is at least K + and K + is from 0.1 to 30% by cation %.
14. The near infrared cutoff filter glass according to claim 1 , wherein the individual amounts of Mg 2+ , Ca 2+ , Sr 2+ , Ba 2+ , and/or Zn 2+ are from 1 to less than 12% by cation % when present.
15. The near infrared cutoff filter glass according to claim 1 , wherein Sb 3+ is from 0.01 to 0.8% by cation %.
16. The near infrared cutoff filter glass according to claim 1 , further comprising Fe 3+ in an amount of less than 0.05% by cation %.
17. The near infrared cutoff filter glass according to claim 1 , an additional cation selected from the ground consisting of Cr 3+ , Ni 2+ , Co 2+ , Mo 3+ , Mn 2+ , and mixtures thereof, wherein said additional cation is in an amount of less than 0.05% by cation %.
18. The near infrared cutoff filter glass according to claim 1 , wherein O 2− is from 30 to 80% by anion %.
19. The near infrared cutoff filter glass according to claim 1 , wherein F − is from 10 to 50% by anion %.