Low-temperature hermetic sealing for diffractive optical element stacks

Patent metadata

Field	Value
Publication number	US-2016238855-A1
Application number	US-201514870040-A
Country	US
Kind code	A1
Filing date	Sep 30, 2015
Priority date	Feb 16, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

A method for producing an optical apparatus includes providing a pair of glass wafers. One or more diffractive optical elements (DOEs) are formed on one or more of the glass wafers. A spacer is positioned between the glass wafers so as to define a cavity containing the DOEs, and a hermetic seal that bonds the glass wafers together and seals the cavity is formed.

First claim

1 . A method for producing an optical apparatus, comprising:
providing a pair of glass wafers; forming one or more diffractive optical elements (DOEs) on one or more of the glass wafers; positioning a spacer between the glass wafers so as to define a cavity containing the DOEs; and forming a hermetic seal that bonds the glass wafers together and seals the cavity.

2 . The method according to claim 1 , wherein forming the DOEs comprises molding a diffractive pattern in a polymer layer.

3 . The method according to claim 1 , wherein forming the DOEs comprises patterning a diffractive pattern in at least one of the glass wafers.

4 . The method according to claim 1 , wherein forming the hermetic seal comprises coating the spacer with a first metal layer.

5 . The method according to claim 4 , wherein the spacer comprises a polymer.

6 . The method according to claim 4 , wherein the spacer comprises a glass.

7 . The method according to claim 1 , wherein positioning the spacer comprises creating the spacer by forming a cavity in one or more of the glass wafers.

8 . The method according to claim 1 , wherein forming the hermetic seal comprises bonding eutectic metal alloys.

9 . The method according to claim 1 , wherein forming the hermetic seal comprises performing direct oxide bonding.

10 . The method according to claim 9 , and comprising, before performing the direct oxide bonding, polishing and cleaning bonding surfaces of at least one of the glass wafers and of the spacer.

11 . The method according to claim 9 , wherein performing the direct oxide bonding comprises heating and pressing the glass wafers towards one another.

12 . The method according to claim 9 , wherein performing the direct oxide bonding comprises pressing the glass wafers toward one another at room temperature.

13 . The method according to claim 1 , wherein the spacer comprises a glass spacer having a first surface, wherein each of the glass wafers has a second surface, and wherein forming the hermetic seal comprises welding the first and second surfaces.

14 . The method according to claim 13 , wherein welding the surfaces comprises performing laser-assisted micro welding.

15 . The method according to claim 1 , wherein forming the hermetic seal comprises forming an electrical conductive polymer coated with a second metal layer.

16 . Optical apparatus, comprising:
a pair of glass wafers; one or more diffractive optical elements (DOEs) formed on one or more of the glass wafers; a spacer positioned between the glass wafers so as to define a cavity containing the DOEs; and a hermetic seal that bonds the glass wafers together and seals the cavity.

17 . The optical apparatus according to claim 16 , wherein the hermetic seal comprises the spacer coated with a first metal layer.

18 . The optical apparatus according to claim 16 , wherein the hermetic seal comprises bonded eutectic metal alloys.

19 . The optical apparatus according to claim 16 , wherein the hermetic seal comprises a direct bonded oxide.

20 . Optical apparatus, comprising:
a light source, which is configured to emit light; and a diffractive optical element (DOE) assembly, which is configured to project a pattern of light in response to the light emitted by the light source, the DOE assembly comprising:
a pair of glass wafers;
one or more DOEs formed on one or more of the glass wafers;
a spacer positioned between the wafers so as to define a cavity containing the DOEs; and
a hermetic seal that bonds the wafers together and seals the cavity.

Assignees

• Apple Inc

Inventors

• Kriman Moshe
• Magen Adar

Classifications

• G02B27/0006

  with means to keep optical surfaces clean, e.g. by preventing or removing dirt, stains, contamination, condensation (G02B1/18 takes precedence; cleaning in general B08B) · CPC title

• G02B7/00

  Mountings, adjusting means, or light-tight connections, for optical elements · CPC title

• G02B5/1857

  using exposure or etching means, e.g. holography, photolithography, exposure to electron or ion beams · CPC title

• G02B27/4277 Primary

  being separated by an air space · CPC title

• G02B5/1852

  using mechanical means, e.g. ruling with diamond tool, moulding · CPC title