Method of making a glass envelope
The coefficient of absorption of a pre-selected region of a glass sheet is preferentially increased. The glass sheet may thereafter be sealed to a substrate using a sealing laser. In one embodiment, the coefficient of absorption sheet is increased by irradiating the glass sheet at a wavelength of about 248 nm, preferably through a mask, to produce an irradiated pattern on the glass sheet having a pre-determined shape. The glass sheet is then heat treated, placed over a substrate and sealed to the substrate by exposing the irradiated pattern to a sealing laser light having a wavelength in the range between about 355 nm and 532 nm to produce a glass envelope. The method disclosed herein is useful, inter alia, for manufacturing electro-luminescent devices, such as light emitting diodes (LEDs) and in particular organic light emitting diodes (OLEDs).
1. A method for making a glass envelope comprising:
providing a first glass sheet having a first side and a second side and doped with Ag or Au;
irradiating a portion of the glass sheet with a first optical energy;
heating treating the glass sheet at a temperature of at least about 480° C.;
positioning the glass sheet over a substrate; and
exposing the irradiated portion of the glass sheet to a second optical energy to fuse the glass sheet to the substrate and form a cavity therebetween.
2. The method according to claim 1 wherein the first optical energy is at a wavelength of about 248 nm.
3. The method according to claim 1 wherein the second optical energy is at a wavelength of between about 300 nm and 600 nm.
4. The method according to claim 1 wherein the step of irradiating comprises irradiating through a mask.
5. The method according to claim 4 wherein the second optical energy has a wavelength of about 420 nm.
6. The method according to claim 1 wherein the irradiated portion comprises a closed path on the first side.
7. The method according to claim 1 wherein the glass sheet comprises a plurality of irradiated patterns.
8. The method according to claim 1 wherein an electro-luminescent layer is disposed within the cavity.
9. The method according to claim 8 wherein the electroluminescent layer comprises an organic material.
10. The method according to claim 1 wherein a chemical composition of the glass sheet and a chemical composition of the substrate are substantially the same.
11. The method according to claim 1 wherein the glass sheet is heat treated for a period of at least about 2 minutes.
12. The method according to claim 1 wherein the glass sheet is heat treated for at least about 1 hour.
13. The method according to claim 1 wherein the glass sheet comprises Ag or Au in an amount between about 0.22 wt. % and 0.66 wt. %.
14. The method according to claim 1 wherein the irradiated portion is less than about 300 mm deep.
15. A method for making a glass envelope comprising:
providing a first glass sheet having a first side and a second side and doped with Ag or Au;
irradiating a portion of the first side of the glass sheet at a wavelength of about 248 nm;
heating treating the glass sheet at a temperature of at least about 480° C.;
positioning the glass sheet over a substrate; and
exposing the irradiated portion to optical energy at a wavelength between about 300 nm and 600 nm to fuse the glass sheet to the substrate and form a cavity therebetween.
16. The method according to claim 15 further comprising irradiating a portion of the second side of the first glass sheet at a wavelength of about 248 nm.
17. The method according to claim 15 further comprising sealing a second glass sheet to the first glass sheet.