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EP-4735397-A1 - WET ETCHING OF HIGH INDEX GLASS FOR SURFACE STRENGTH IMPROVEMENT

EP4735397A1EP 4735397 A1EP4735397 A1EP 4735397A1EP-4735397-A1

Abstract

Methods for making a glass article include etching the surfaces of the glass article with an etchant solution that includes hydrofluoric acid to produce an etched glass article. The glss article being a high index glass containing transition metal oxides and having an index of refraction greater than or equal to about 1.6 at 589.3 nm wavelength. The surface having surface and subsurface defects. The etching improves a surface strength of the surfaces of the etched glass article by removing or rounding the surface and subsurface defects, and the etching causes deposition of transition metal fluorides. The methods include cleaning the surfaces of the etched glass article with a cleaning solution having a pH of greater than or equal to about 10 to remove transition metal fluorides from the surfaces of the etched glass article.

Inventors

  • FENG, JIANGWEI
  • ORCUTT, Timothy James
  • SHAFRIR NEGEV, Shai
  • SZABO, Istvan Laszlo

Assignees

  • Corning Incorporated

Dates

Publication Date
20260506
Application Date
20240523

Claims (20)

  1. 1. A method for making a glass article, the method comprising: etching at least one surface of a glass article with an etchant solution comprising hydrofluoric acid (HF) to produce an etched glass article, the glass article comprising a high index glass, the high index glass comprising transition metal oxides and having an index of refraction of greater than or equal to about 1.60 at a wavelength of 589.3 nm, the at least one surface comprising surface and subsurface defects, wherein the etching improves a Bio surface strength of the at least one surface of the etched glass article by removing or rounding the surface and subsurface defects; and the etching causes the deposition of transition metal fluorides onto the at least one surface of the etched glass article; and cleaning the at least one surface of the etched glass article with a high pH cleaning solution having a pH of greater than or equal to about 10.0, wherein the cleaning solution removes the transition metal fluorides from the at least one surface of the etched glass article.
  2. 2. The method of claim 1, wherein the etchant solution comprises from about 1 molar (M) to about 8.0 M HF.
  3. 3. The method of claim 1 or 2, wherein the etchant solution further comprises one or more ofHCl, H2SO4, or HNO 3 .
  4. 4. The method of any of claims 1-3, wherein the etchant solution comprises HF and HC1 in a molar ratio of HF to HC1 of from about 1.0 to about 3.0, or from about 1.5 to about 2.0.
  5. 5. The method of any of claims 1-4, wherein the high pH cleaning solution comprises ammonium hydroxide, NaOH, KOH, a high pH glass cleaning detergent, or combinations thereof.
  6. 6. The method of any of claims 1-5, wherein the transition metal fluorides comprise LaFs and the contacting the etched glass article with the high pH cleaning solution removes the LaFs deposited onto the at least one surface of the etched glass article.
  7. 7. The method of any of claims 1-6, wherein the surface and subsurface defects on the at least one surface of the glass article before etching limits the Bw surface strength of the at least one surface of the glass article to less than or equal to about 250 N, as determined from a ring- on-ring (RoR) test according to ASTM: Cl 499-09.
  8. 8. The method of any of claims 1-7, wherein the etching increases the Bio surface strength, as determined from a ring-on-ring (RoR) test according to ASTM: Cl 499-09, of the at least one surface of the etched glass article by at least about 50% compared to the glass article before the etching.
  9. 9. The method of any of claims 1-8, wherein the transition metal oxides comprise one or more metal oxides selected from lanthanum oxide, niobium oxide, tungsten oxide, or combinations thereof.
  10. 10. The method of any of claims 1-9, wherein the high index glass comprises from about 10.0 mol% to about 40.0 mol% B2O3, from greater than or equal to 0 mol% to about 40.0 mol% WO3, from greater than or equal to 0 mol% to about 30.0 mol% bfeOs, from greater than or equal to 0 mol% to about 30.0 mol% TiCh, from greater than or equal to 0 mol% to about 25.0 mol% La20s, and from greater than or equal to 0 mol% to about 15.0 mol% ZrCh based on the total moles of the high index glass.
  11. 11. The method of any of claims 1-10, wherein the high index glass comprises greater than about 15.0 mol% La2Os.
  12. 12. The method of any of claims 1-11, wherein the transition metal fluorides comprise LaFs.
  13. 13. The method of any of claims 1-12, wherein the high index glass comprises less than or equal to about 1 mol% silica.
  14. 14. A glass article comprising a high index glass, the high index glass comprising greater than about 10.0 mol% La2Os and having a refractive index greater than about 1.60 at a wavelength of 589.3 nm, the glass article having at least one surface with a Bw surface strength, as determined from a ring-on-ring (RoR) test according to ASTM: C1499-09, greater than 300 N.
  15. 15. The glass article of claim 14, wherein the high index glass further comprises greater than about 20.0 mol% B2O3.
  16. 16. The glass article of claim 14 or 15, wherein the high index glass further comprises greater than about 4.0 mol% ZrCh.
  17. 17. The glass article of any of claims 14-16, wherein the high index glass further comprises greater than about 5.0 mol% TiCh.
  18. 18. The glass article of any of claims 14-17, wherein the high index glass further comprises greater than about 10.0 mol% bfeOs.
  19. 19. The glass article of any of claims 14-18, wherein the high index glass further comprises greater than about 10.0 mol% WO3.
  20. 20. The glass article of any of claims 14-19, wherein the Bio surface strength is greater than 500 N.

Description

WET ETCHING OF HIGH INDEX GLASS FOR SURFACE STRENGTH IMPROVEMENT BACKGROUND [0001] This application claims the benefit of priority under 35 U.S.C §120 of U.S. Provisional Application Serial No. 63/523,681 filed on June 28, 2023, the content of which is relied upon and incorporated herein by reference in its entirety. Field [0002] The present specification generally relates to glass, and particularly to methods of producing high refractive index glass articles. Technical Background [0003] Glass is used in a variety of optical devices, examples of which include augmented reality devices, virtual reality devices, mixed reality devices, eyewear, etc. Desirable properties for this type of glass often include a high refractive index and a low density. Additional desirable properties may include high transmission in the visible and near-ultraviolet ("near-UV") range of the electromagnetic spectrum and/or low optical dispersion. It can be challenging to find glasses that have the desired combination of these properties and that can be formed from compositions having good glass-forming ability. SUMMARY [0004] A first aspect of the present disclosure may be directed to a method of making a glass article, the method comprising etching at least one surface of a glass article with an etchant solution comprising hydrofluoric acid (HF) to produce an etched glass article, the glass article comprising a high index glass, the high index glass comprising transition metal oxides and having an index of refraction of greater than or equal to about 1.60 at a wavelength of 589.3 nm, the at least one surface comprising surface and subsurface defects. The etching may improve a surface strength of the at least one surface of the etched glass article by removing or rounding the surface and subsurface defects. The etching may cause the deposition of transition metal fluorides onto the at least one surface of the etched glass article. The method may further include cleaning the at least one surface of the etched glass article with a high pH cleaning solution having a pH of greater than or equal to about 10.0, wherein the cleaning solution removes the transition metal fluorides from the at least one surface of the etched glass article. [0005] A second aspect disclosed herein may include the first aspect, wherein the etchant solution may comprise from about 1.0 molar (M) to about 8.0 M HF. [0006] A third aspect disclosed herein may include either one of the first or second aspects, wherein the etchant solution may further comprise one or more of HC1, H2SO4, or HNO3. [0007] A fourth aspect disclosed herein may include the third aspect, wherein the etchant solution may comprise from about 2.0 M to about 10.0 M HC1, H2SO4, HNO3, or any combination thereof. [0008] A fifth aspect disclosed herein may include any one of the first through fourth aspects, wherein the etchant solution may comprise HF and HC1 in a molar ratio of HF to HC1 of from about 1.0 to about 3.0, or from about 1.5 to about 2.0. [0009] A sixth aspect disclosed herein may include any one of the first through fifth aspects, wherein an etch rate of the etching may be from about 0.01 pm/sec to about 0.5 pm/sec. [0010] A seventh aspect disclosed herein may include any one of the first through sixth aspects, wherein the etching may remove from about 1 pm to about 10 pm of glass from the at least one surface of the etched glass article. [0011] An eighth aspect disclosed herein may include any one of the first through seventh aspects, wherein a temperature of the etching may be from about 20 °C to about 45 °C, or about 25 °C. [0012] A ninth aspect disclosed herein may include any one of the first through eighth aspects, wherein the high pH cleaning solution may comprise ammonium hydroxide, NaOH, KOH, a high pH glass cleaning detergent, or combinations thereof. [0013] A tenth aspect disclosed herein may include any one of the first through ninth aspects, wherein the cleaning the etched glass article may comprise submerging the etched glass article in the high pH cleaning solution at a temperature of from about 55 °C to about 70 °C for a contact duration of from about 5 minutes to about 20 minutes. [0014] An eleventh aspect disclosed herein may include any one of the first through tenth aspects, wherein the transition metal fluorides may comprise LaFs and the contacting the etched glass article with the high pH cleaning solution may remove the LaFs deposited onto the at least one surface of the etched glass article. [0015] A twelfth aspect disclosed herein may include any one of the first through eleventh aspects, further comprising polishing the at least one surface of the etched glass article with colloidal silica or with a slurry of AI2O3 or ZrCh to produce a finished glass article. [0016] A thirteenth aspect disclosed herein may include any one of the first through twelfth aspects, wherein the at least one surface of the finished glass article may have a root mean square roughn