Raised features on transparent substrates and related methods
Raised features are formed on a transparent substrate having absorption of less than about 20% within a processing wavelength range. A portion of the substrate is irradiated with a light beam to increase the absorption of the irradiated portion of the substrate. Continued irradiation causes local heating and expansion of the substrate so as to form a raised feature on the substrate surface.
1. A method for forming a raised feature on a transparent substrate, the method comprising the steps of:
providing a transparent substrate having a surface, the substrate having an absorption of less than about 20% within a processing wavelength range;
irradiating a portion of the transparent substrate with a processing light beam within the processing wavelength range for at least one second to increase the absorption of the irradiated portion of the substrate in the processing wavelength range;
continuing to irradiate the portion of the transparent substrate within the processing wavelength range to cause local heating and expansion of the substrate so as to form a raised feature on the substrate surface; and
terminating the irradiation to stop heating of the substrate so as to fix the raised feature.
2. The method of claim 1 , wherein irradiating a portion of the transparent substrate with a processing light beam to increase the absorption of the irradiated portion of the substrate in the processing wavelength range includes generating photo-induced absorption within the processing wavelength range in the irradiated portion of the substrate.
3. The method of claim 2 , wherein generating photo-induced absorption comprises changing the oxidation state of ions in the substrate within the irradiated portion.
4. The method of claim 3 , wherein changing the oxidation state of ions in the substrate within the irradiated portion comprises changing the oxidation state of ions that do not absorb in a visible wavelength.
5. The method of claim 2 , wherein generating photo-induced absorption comprises causing light absorbing defects in the substrate within the irradiated portion.
6. The method of claim 1 , wherein the transparent substrate comprises one of alkaline earth aluminosilicate glass, soda-lime glass, and sodium aluminosilicate glass.
7. The method of claim 1 , wherein the transparent substrate includes therein at least one of antimony (Sb), arsenic (As), tin (Sn), iron (Fe), cerium (Ce), lead (Pb), transition metals, and oxides thereof.
8. The method of claim 1 , wherein the transparent substrate has a coefficient of thermal expansion between about 30 and about 120.
9. The method of claim 1 , wherein the transparent substrate has an annealing point less than about 900° C.
10. The method of claim 1 , wherein the processing light beam comprises one of an ultraviolet wavelength, a near-ultraviolet wavelength, a near-infrared wavelength, and an infrared wavelength.
11. The method of claim 10 , wherein the processing light beam comprises a wavelength less than about 380 nm.
12. The method of claim 1 , wherein continuing to irradiate the portion of the transparent substrate within the processing wavelength range comprises continuing to irradiate the portion of the transparent substrate with the processing light beam.
13. The method of claim 1 , wherein irradiating a portion of the transparent substrate with a processing light beam within the processing wavelength range comprises irradiating the portion of the transparent substrate with a first processing light beam having a first wavelength; and wherein continuing to irradiate the portion of the transparent substrate within the processing wavelength range comprises irradiating the portion with a second processing light beam having a second wavelength.
14. A method for forming a raised feature on a transparent substrate, the method comprising the steps of:
providing a transparent substrate having a surface, the substrate having an absorption of less than about 20% within a first wavelength range;
irradiating a portion of the transparent substrate with light within the first wavelength range for at least one second to increase absorption within the irradiated portion of the transparent substrate to greater than about 40% within a second wavelength range;
irradiating the portion of the transparent substrate with light within the second wavelength range to cause local heating and expansion of the substrate so as to form a raised feature on the substrate surface; and
terminating the irradiating to stop heating of the substrate so as to fix the raised feature.
15. The method of claim 14 , wherein the first wavelength range and the second wavelength range at least partially overlap.
16. The method of claim 14 , wherein the first wavelength range and the second wavelength range do not overlap.