Glasses for the correction of chromatic and thermal optical aberations for lenses transmitting in the near, mid, and far-infrared sprectrums
The invention relates to chalcogenide glass compositions for use in a lens system to balance thermal effects and chromatic effects and thereby provide an achromatic and athermal optical element that efficiently maintains achromatic performance across a broad temperature range. The glass composition is based on sulfur compounded with germanium, arsenic and/or gallium, and may further comprise halides of, for example, silver, zinc, or alkali metals. Alternatively, is based on selenium compounded with gallium, and preferably germanium, and contains chlorides and/or bromides of, for example, zinc, lead or alkali metals.
1. A chalcogenide glass composition comprising (based on mol % of total moles):
Component
Mole %
Se
30.00-68.00
Ga
5.00-30.00
Ge
0-25.00
R 1
0-25.00
(added in the form of
R 1 Hal 1 )
R 2
0-25.00
(added in the form of
R 2 Hal 1 )
M 1
0-12.50
(added in the form of
M 1 Hal 1 2 )
M 2
0-20.00
(added in the form of
M 2 Hal 1 2 )
Ln
0-8
(added in the form of
LnHal 1 3 )
Sum of Se, Ga, and Ge
50.00-93.33
Sum of R 1 , R 2 , M 1 , M 2 and
1.67-25.00
Ln
Sum of Hal 1
6.00-25.00
wherein
Hal 1 =chloride and/or bromide,
R 1 =Li, Na, K, Rb, and/or Cs,
R 2 =Ag and/or Cu,
M 1 =Mg, Ca, Sr, and/or Ba,
M 2 =Zn, Cd, Hg, and/or Pb, and
Ln=La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Ty, Lu, Y, and Sc; and
wherein a portion of the gallium can be replaced by indium.
2. A chalcogenide glass composition according to claim 1 , wherein said composition comprises (based on mol %):
Component
Mole %
Se
30.00-68.00
Ga
5.00-30.00
Ge
0-25.00
R 1
0-25.00
(added in the form of
R 1 Hal 1 )
R 2
0-25.00
(added in the form of
R 2 Hal 1 )
M 1
0-12.50
(added in the form of
M 1 Hal 1 2 )
M 2
0-20.00
(added in the form of
M 2 Hal 1 2 )
Ln
0-8
(added in the form of
LnHal 1 3 )
Sum of Se, Ga, and Ge
50.00-93.33
Sum of R 1 , R 2 , M 1 , M 2 , and
1.67-25.00
Ln
Sum of Hal 1
6.00-25.00.
3. A chalcogenide glass composition according to claim 2 , wherein said composition comprises (based on mol %):
Component
Mole %
Se
35.00-65.00
Ga
7.00-22.00
Ge
18.00-23.00
R 1
0-20
(added in the form of
R 1 Hal 1 )
R 2
0-20.00
(added in the form of
R 2 Hal 1 )
M 1
0-10
(added in the form of
M 1 Hal 1 2 )
M 2
0-15.00
(added in the form of
M 2 Hal 1 2 )
Ln
0-5
(added in the form of
LnHal 1 3 )
Sum of Se, Ga, and Ge
55.00-85.00
Sum of R 1 , R 2 , M 1 , M 2 and
1.67-22.00
Ln
Sum of Hal 1
7.5-22.00.
4. A chalcogenide glass composition according to claim 2 , wherein said composition contains 30.00-65.00 mol % of selenium.
5. A chalcogenide glass composition according to claim 2 , wherein said composition contains 15-25.00 mol % Ge.
6. A chalcogenide glass composition according to claim 2 , wherein said composition contains 5-22.00 mol % Ga.
7. A chalcogenide glass composition according to claim 2 , wherein a portion of the gallium is replaced by indium.
8. A chalcogenide glass composition according to claim 2 , wherein said composition contains 6.00-15.00 mol % Hal 1 .
9. A chalcogenide glass composition according to claim 2 , wherein said composition contains 7.00-25.00 mol % Hal 1 .
10. A chalcogenide glass composition according to claim 2 , wherein said composition contains 7.00-15.00 mol % Hal 1 .
11. A chalcogenide glass composition according to claim 2 , wherein said composition contains 6.00-10.00 mol % Hal 1 .
12. A chalcogenide glass composition according to claim 2 , wherein said composition contains 7.00-10.00 mol % Hal 1 .
13. A chalcogenide glass composition according to claim 2 , wherein said composition contains 0 mol % Ge.
14. In a night vision device comprising an infrared optical element, an image enhancer or intensifier, and a phosphor or fluorescent display, the improvement wherein said infrared optical element comprises a lens made of from a chalcogenide glass composition according to claim 1 .
15. In an infrared or thermal imaging system comprising an infrared optical element, a plurality of thermal sensors for detecting the infrared light and converting it into electrical signals, and a signal-processing unit for converting the electrical signals into a visual image, the improvement wherein said infrared optical element comprises a lens made of from a chalcogenide glass composition according to claim 1 .
16. A doublet lens comprising an infrared lens paired with a corrective lens wherein said infrared lens is made of ZnSe, ZnS, Ge, GaAs, BaF 2 , or chalcogenide glass, and said corrective lens made from a chalcogenide glass composition according to claim 1 .
17. An infrared lens system comprising a first infrared lens and a focal corrector doublet lens comprising a pair of corrective lenses, wherein said first infrared lens is made of ZnSe, ZnS, Ge, GaAs, BaF 2 , or chalcogenide glass, one of said pair of corrective lenses has a positive power and the other has a negative power, and at least one of said pair of corrective lens is made from a chalcogenide glass composition according to claim 1 .