Compositions and methods to fabricate a photoactive substrate suitable for shaped glass structures

Abstract

A shaped photosensitive glass composition comprising silica, K 2 O, Na 2 O, Ag 2 O, B 2 O 3 , Al 2 O 3 , Li 2 O, and CeO 2 with a high anisotropic-etch ratio formed by a novel construction method. Furthermore, such shaped glass structures can be used to form a negative mold for casting the shape in other materials. Structures of the photosensitive glass composition may include micro-channels, micro-optics, microposts, or arrays of hollow micro-needles.

What is claimed: 
     
         1 . A shaped glass structure with a high anisotropic-etch ratio comprising:
 a photosensitive glass substrate with a glass transformation temperature, wherein the photosensitive glass substrate comprises:   a glass composition comprising   60-76 weight % silica,   6 weight %-16 weight % of a combination of K 2 O and Na 2 O with   at least 3 weight % K 2 O,   0.001-1 weight % Ag 2 O,   0.75 weight %-7 weight % B 2 O 3 , and   5-8 weight % Al 2 O 3 , with the combination of B 2 O 3 , and Al 2 O 3  not exceeding 13 weight %,   8-15 weight % Li 2 O, and   0.04-0.1 weight % CeO 2 , and   one or more patterned structure.   
     
     
         2 . The shaped glass structure of  claim 1 , wherein the patterned structure comprises at least one portion exposed to an activating energy source, such as ultraviolet light, while leaving at least a second portion of the glass substrate unexposed, wherein at least a part of the exposed portion is a crystalline material formed by heating the glass substrate to a temperature near the glass transformation temperature, wherein when etching the glass substrate in an etchant, the anisotropic-etch ratio of the exposed portion to the unexposed portion is at least 30:1 when the glass is exposed to a broad spectrum mid-ultraviolet flood lamp, to provide a shaped glass structure with an aspect ratio of at least 30:1, and to provide shaped glass structures with an aspect ratio much greater than 30:1 when the glass is exposed using a high powered energy source, such as a laser. 
     
     
         3 . The shaped glass structure of  claim 1 , wherein the glass composition is essentially germanium-free. 
     
     
         4 . The shaped glass structure of  claim 1 , wherein the glass composition comprises at least 0.5 weight % B 2 O 3 . 
     
     
         5 . The shaped glass structure of  claim 1 , wherein the glass composition comprises at least 1.25 weight % B 2 O 3 . 
     
     
         6 . The shaped glass structure of  claim 1 , wherein the glass composition comprises at least 0.3 weight % Sb 2 O 3  or As 2 O 3 . 
     
     
         7 . The shaped glass structure of  claim 1 , wherein the glass composition comprises 0.003-1 weight % Au 2 O. 
     
     
         8 . The shaped glass structure  claim 1 , wherein the glass composition contains 1-18 weight % of an oxide selected from the group consisting of CaO, ZnO, PbO, MgO and BaO. 
     
     
         9 . The shaped glass structure of  claim 1 , wherein the glass composition contains 0-5 weight %, iron (Fe 2 O 3 ) to make the composition paramagnetic and/or to use iron (II) and iron (III) to quench intrinsic autofluorescence. 
     
     
         10 . The shaped glass structure of  claim 1 , wherein the glass composition comprises up to 2 weight % Copper Oxide. 
     
     
         11 . The shaped glass structure of  claim 1 , wherein the anisotropic-etch ratio of exposed portion to the unexposed portion is 30-45:1. 
     
     
         12 . The shaped glass structure of claim  22 , wherein the anisotropic-etch ratio of exposed portion to said unexposed portion is at least one of 10-20:1; 21-29:1; 30-45:1; 20-40:1; 41-45:1; and 30-50:1. 
     
     
         13 . The shaped glass structure of  claim 1 , wherein the etchant comprises hydrofluoric acid. 
     
     
         14 . The shaped glass structure of  claim 1 , wherein the wavelength of the ultraviolet light is about 308-312 nm.