Increased accuracy corner cube arrays for high resolution retro-reflective imaging applications

Patent metadata

Field	Value
Publication number	US-2016103255-A1
Application number	US-201414538783-A
Country	US
Kind code	A1
Filing date	Nov 11, 2014
Priority date	Oct 10, 2014
Publication date	Apr 14, 2016
Grant date	—

Abstract

Tooling and optic elements for a retro-imaging system may be formed on order near atomic level of accuracy by making use of either etching or growth techniques of a cubic crystal lattice, such as silicon. The elements may be formed directly using selective etching or epitaxial growth by coating and clear resin lamination, or replicated to avoid shrinkage and curvature by use of low shrinkage resins or double-fill molding techniques. Through the use of these highly accurate reflection/diffraction elements, floating images may be formed with relatively high resolution in retro-reflective imaging systems, for example.

First claim

What is claimed is:

1 . A retro-reflective array comprising:
a corner cube array; and a reflective surface covering facets of a plurality of corner cube structures of the corner cube array.

2 . The retro-reflective array of claim 1 , wherein a pitch for the corner cube structures is determined based on a type of the retro-reflective array and a tradeoff of a diffraction and an image breakup caused by the retro-reflective array such that a resolution loss is reduced and a modulation transfer function (MTF) of the retro-reflective array is increased.

3 . The retro-reflective array of claim 1 , wherein the reflective surface covering facets of the plurality of corner cube structures comprises one of:
reflective coating directly applied to the facets of the plurality of corner cube structures; reflective coating applied over a replicated retro-reflective array; and the facets of the plurality of corner cube structure rendered reflective through total internal reflection (TIR).

4 . The retro-reflective array of claim 1 , further comprising one of:
a clear resin layer applied over the plurality of corner cubes; and a flat layer of optically clear resin fill media molded over the retro-reflective array.

5 . The retro-reflective array of claim 4 , further comprising:
a clear substrate applied over the clear resin layer, wherein the clear substrate includes birefringence on one of an outer surface and an inner surface.

6 . The retro-reflective array of claim 5 , further comprising one of:
an anti-reflective coating applied on the clear substrate; and the anti-reflective coating applied on an outer surface of a retarder layer if the retarder layer is laminated on the outer surface.

7 . A display system comprising:
one or more light sources; and a beam splitter configured to partially reflect source light from the one or more light sources to a retro-reflective array, the retro-reflective array comprising a reflective surface formed by one or more corner cube arrays (CCAs), wherein the retro-reflective array is configured to reflect the source light through the beam splitter so that the light is reconvergent.

8 . The system of claim 7 , wherein the retro-reflective array is configured to reflect the source light through the beam splitter by direct use of the CCAs' reflective surface as first surface.

9 . The system of claim 7 , wherein the retro-reflective array is configured to reflect the source light through the beam splitter by use of a lamination as a second surface on a backside of a clear substrate covering the CCAs.

10 . The system of claim 7 , wherein the retro-reflective array is configured to reflect the source light through the beam splitter by use of a replication of the CCAs with a low shrinkage clear resin covered by a reflective coating or a replication of the CCAs through multiple molding cycles on a single molded part to reduce a thermal shrinkage impact.

11 . The system of claim 7 , wherein the CCAs are formed through selective epitaxial growth of silicon of a <111> oriented silicon wafer.

12 . The system of claim 7 , wherein a pitch for the CCAs is determined based on a type of the retro-reflective array and a tradeoff of a diffraction and an image breakup caused by the retro-reflective array.

13 . A corner cube array (CCA) based retro-reflective array fabrication system, the fabrication system comprising:
a growth module configured to employ selective epitaxial growth to form a plurality of corner cube structures on a wafer; a coating module configured to apply reflective coating to one of facets of the plurality of corner cube structures to form a first surface reflector or to a backside of a clear substrate formed over the plurality of corner cube structures using a clear resin to form a second surface reflector; and a controller configured to determine a pitch for the corner cube structures based on a tradeoff of a diffraction and an image breakup caused by the retro-reflective array.

14 . The fabrication system of claim 13 , further comprising:
a lamination module configured to:
apply a clear resin layer over the plurality of corner cubes; and
apply an anti-reflective coating on the substrate.

15 . The fabrication system of claim 13 , further comprising:
a replication module configured to:
fabricate multiple replicas of a master tile cut from the wafer; and
tile the replicas to form a larger new master tile.

16 . The fabrication system of claim 15 , wherein the replication module is configured to fabricate the multiple replicas through replication in a polymer sheet or an electroform nickel.

17 . The fabrication system of claim 15 , wherein the replication module is configured to tile the replicas by cutting and sizing through one or more of milling, grinding, polishing, and electron discharge machining (EDM).

18 . The fabrication system of claim 15 , wherein the replication module is configured to:
fabricate mold inserts for high volume replication; and control heating of surface layers of the mold inserts for embossing by employing one or more from a list consisting of the following: induction heating, flash steam heating and cooling fluids.

19 . The fabrication system of claim 15 , wherein the growth module is configured to form the plurality of corner cube structures on the wafer through selective epitaxial growth of silicon of the <111> oriented silicon wafer.

20 . The fabrication system of claim 19 , wherein the growth module is configured to form the plurality of corner cube structures on the wafer through vapor selective epitaxial growth using materials selected from a list consisting of the following: trichlorisilane, hydrogen-chloride, and hydrogen gas.

Assignees

• Microsoft Technology Licensing Llc

Inventors

• Powell Karlton
• Lutian John

Classifications

• G02B30/56

  by projecting aerial or floating images · CPC title

• G03B21/60

  characterised by the nature of the surface · CPC title

• G02B1/113 Primary

  using inorganic layer materials only · CPC title

• G02B5/124 Primary

  plural reflecting elements forming part of a unitary plate or sheet · CPC title