An optical module in which the light outputted from the light source is condensed before outputted, and yet capable of reducing the development of contaminants on the light condensing area. The optical module includes: a light source for outputting light in the short wavelength region; a transparent member having a light input face and a light output face; and a condensing optical system for inputting the light outputted from the light source to the input face of the transparent member, and focusing the light on the output face. The transparent member has an alkali metal content (e.g. Na or K) of less than 2.0% by weight, and/or with a light absorption of less than 0.65%/mm for the light outputted from the light source.
1. An optical module comprising:
at least one light source for outputting light in the short wavelength region;
a transparent member having a light input face and a light output face; and
a condensing optical system for inputting the light outputted from the light source to the input face of the transparent member, and focusing the light on the output face,
wherein the transparent member has an alkali metal content of less than 2.0% by weight, and
wherein the transparent member is a glass member including at least one material selected from the group consisting of SiO 2 , CaF 2 , and MgF 2 .
2. The optical module according to claim 1 , wherein the transparent member has a uniform refractive index.
3. The optical module according to claim 1 , wherein the oscillation wavelength of the light outputted from the light source is in the range of 350 nm to 450 nm.
4. The optical module according to claim 1 , wherein the length of the transparent member in the optical axis directions is not less than 1 mm.
5. The optical module according to claim 1 , wherein an antireflection coating is applied on the input face of the transparent member.
6. An optical module comprising:
at least one light source for outputting light in the short wavelength region;
a transparent member having a light input face and a light output face; and
a condensing optical system for inputting the light outputted from the light source to the input face of the transparent member, and focusing the light on the output face,
wherein the transparent member has Na and K contents of less than 2.0% by weight respectively.
7. The optical module according to claim 6 , wherein the transparent member has a uniform refractive index.
8. The optical module according to claim 6 , wherein the transparent member is a glass member including at least one material selected from the group consisting of SiO 2 , CaF 2 , and MgF 2 .
9. The optical module according to claim 6 , wherein the oscillation wavelength of the light outputted from the light source is in the range of 350 nm to 450 nm.
10. The optical module according to claim 6 , wherein the length of the transparent member in the optical axis directions is not less than 1 mm.
11. The optical module according to claim 6 , wherein an antireflection coating is applied on the input face of the transparent member.
12. An optical module comprising:
at least one light source for outputting light in the short wavelength region;
a transparent member having a light input face and a light output face; and
a condensing optical system for inputting the light outputted from the light source to the input face of the transparent member, and focusing the light on the output face,
wherein the transparent member has a light absorption of less than 0.65%/mm for the light outputted from the light source.
13. The optical module according to claim 12 , wherein the transparent member has an alkali metal content of less than 2.0% by weight.
14. The optical module according to claim 12 , wherein the transparent member has Na and K contents of less than 2.0% by weight respectively.
15. The optical module according to claim 12 , wherein the transparent member has a uniform refractive index.
16. The optical module according to claim 12 , wherein the transparent member is a glass member including at least one material selected from the group consisting of SiO 2 , CaF 2 , and MgF 2 .
17. The optical module according to claim 12 , wherein the oscillation wavelength of the light outputted from the light source is in the range of 350 nm to 450 nm.
18. The optical module according to claim 12 , wherein the length of the transparent member in the optical axis directions is not less than 1 mm.
19. The optical module according to claim 12 , wherein an antireflection coating is applied on the input face of the transparent member.