Bottom up apparatus design for formation of self-propagating photopolymer waveguides

• US 10,705,429 B2
• Filed: 08/02/2018
• Issued: 07/07/2020
• Est. Priority Date: 10/24/2016
• Status: Active Grant

• Current Assignee: HRL Laboratories LLC (The Boeing Co.)
• Original Assignee: HRL Laboratories LLC (The Boeing Co.)
• Inventors: Yang, Sophia S., Jacobsen, Alan J., Kolodziejska, Joanna A., Doty, Robert E., Carter, William, Hundley, Jacob M.
• Primary Examiner(s): Daniels, Matthew J
• Assistant Examiner(s): Kim, Yunju
• Application Number:
  US16/053,250
• Publication Number:
  US 20180341181A1
• Time in Patent Office: 705 Days
• Field of Search: 425174, 430320, 355 67
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: G02B 2006/1219 Polymerisation
• CPC Class Codes: G02B 6/12002 Three-dimensional structures
• CPC Class Codes: G02B 6/138 by using polymerisation
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• CPC Class Codes: G03F 7/2008 characterised by the reflectors, diffusers, light or heat filtering means or anti-reflective means used
• CPC Class Codes: G03F 7/201 characterised by an oblique exposure; characterised by the use of plural sources; characterised by the rotation of the optical device; characterised by a relative movement of the optical device, the light source, the sensitive system or the mask
• CPC Class Codes: G03F 7/2012 using liquid photohardening compositions, e.g. for the production of reliefs such as flexographic plates or stamps
• CPC Class Codes: G03F 7/70058 Mask illumination systems
• CPC Class Codes: G03F 7/70416 2.5D lithography

Abstract

A system for forming a micro-truss structure including a reservoir having walls and a flat bottom configured to hold a volume of a liquid photomonomer configured to form a photopolymer when exposed to light, a partially transparent mask secured to, or being, the bottom of the reservoir, a release layer on the mask configured to resist adhesion by the photopolymer, and a blocker positioned a first distance below the mask. The system also includes a light source positioned below the blocker configured to produce collimated light suitable for causing conversion of the photomonomer into the photopolymer, and to which the blocker is opaque, and a first mirror, oblique to the blocker, configured to reflect the light from the light source around the blocker and through the mask and into the reservoir. The blocker is positioned to block a straight path of light from the light source to the mask.

Claims

1. A system for forming a micro-truss structure, the system comprising:

a reservoir having walls and a flat bottom, configured to hold a volume of a liquid photomonomer, the photomonomer being configured to form a photopolymer when exposed to light;

a partially transparent mask secured to, or being, the bottom of the reservoir;

a release layer on the mask, the release layer being configured to resist adhesion by the photopolymer;

a blocker positioned a first distance below the mask, wherein the blocker is non-reflective;

a light source positioned below the blocker, configured to produce collimated light suitable for causing conversion of the photomonomer into the photopolymer, and to which the blocker is opaque; and

a first mirror, oblique to the blocker, configured to reflect the light from the light source around the blocker and through the mask and into the reservoir, the blocker being positioned to block a straight path of light from the light source to the mask.

2. The system of claim 1, wherein the release layer comprises, as a major component, a compound selected from the group consisting of sprayable mold release compounds, polyvinyl chlorides, polyvinylidene chlorides, and combinations thereof.

3. The system of claim 2, wherein the mask is the bottom of the reservoir.

4. The system of claim 1, wherein the bottom of the reservoir is composed of the same material as the walls of the reservoir, and the bottom of the reservoir is integral with the walls of the reservoir.

5. The system of claim 4, wherein the release layer comprises, as a major component, a compound selected from the group consisting of polyvinyl chlorides, polyvinylidene chlorides, and combinations thereof, and wherein the release layer is the bottom of the reservoir.

6. The system of claim 1, further comprising a substrate on the release layer, the substrate being a flat sheet configured to become part of the micro-truss structure, the substrate comprising, as a major component, a compound selected from the group consisting of acrylic, polyethylene terephthalate, and combinations thereof.

7. The system of claim 6, wherein the release layer comprises, as a major component, a compound selected from the group consisting of sprayable mold release compounds, polyvinyl chlorides, polyvinylidene chlorides, and combinations thereof.

8. The system of claim 6, wherein the mask is the bottom of the reservoir.

9. The system of claim 1, wherein the mask comprises:

a flat sheet comprising, as a major component, a material selected from the group consisting of polyvinyl chlorides, polyvinylidene chlorides, paraformaldehydes, fluorinated ethylene propylenes, polyvinylidene fluorides, polytetrafluoroethylene, polyesters, poly(methyl methacrylate), polyethylene terephthalate, UV transparent glasses, and combinations thereof; and

an opaque coating on the flat sheet, the opaque coating having a plurality of apertures.

10. The system of claim 9, wherein the opaque coating comprises, as a major component, a metal or alloy.

11. The system of claim 1 further comprising a housing below the bottom of the reservoir, configured to hold the mask, and configured to permit removal and/or insertion of the mask without disturbing the reservoir or its contents.

12. The system of claim 1, wherein the blocker is positioned to block every straight path of light from the light source to the mask.

13. The system of claim 1, further comprising a second mirror, wherein:

the mask is square,

the first mirror has an upper edge adjacent to a first edge of the mask, and

the second mirror has an upper edge adjacent to a second edge of the mask, opposite the first edge.

14. The system of claim 13, wherein the upper edge of the first mirror is at the same height as the upper edge of the second mirror, and the upper edge of the first mirror is parallel to the upper edge of the second mirror.

15. The system of claim 14, wherein an angle of depression of the second mirror is the same as an angle of depression of the first mirror.

16. The system of claim 15, wherein:

a gap between the upper edge of the first mirror and the first edge of the mask has a maximum width less than 5 mm, and

a gap between the upper edge of the second mirror and the second edge of the mask has a maximum width less than 5 mm.

17. The system of claim 1, wherein the light source is selected from the group consisting of arrays of light-emitting diodes, mercury arc lamps, lasers, and combinations thereof.