System and method for curved light sheet projection during two-photon polymerization

Patent metadata

Field	Value
Publication number	US-11150484-B2
Application number	US-201815983872-A
Country	US
Kind code	B2
Filing date	May 18, 2018
Priority date	May 18, 2018
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

A laser-based manufacturing system is disclosed for fabricating non-planar three-dimensional layers. The system may have a laser for producing a laser beam with a plurality of optical wavelengths. An optically dispersive element may be used for receiving the laser beam and splitting the beam into a plurality of distinct beam components, wherein each beam component has spatially separated optical spectral components. A phase mask may be used which is configured to receive at least one of the beam components emerging from the dispersive element and to create a modified beam. One or more focusing elements may then be used to receive the modified beam emerging from the phase mask and to focus the modified beam into a non-planar light sheet for use in fabricating a part.

First claim

What is claimed is:

1. A laser-based manufacturing system for fabricating non-planar three-dimensional layers, the system comprising:
a laser for producing a laser beam with a plurality of optical wavelengths;
an optically dispersive element for receiving the laser beam and splitting the laser beam into a diverging beam having a plurality of distinct beam components of differing wavelengths, wherein each said beam component has spatially separated optical spectral components;
a phase mask spaced from the optically dispersive element by a predetermined distance, and configured to receive at least one of the distinct beam components emerging from the optically dispersive element and to generate a diverging modified beam which defines a planar light sheet; and
one or more focusing elements configured to receive the diverging modified beam emerging from the phase mask and to focus the diverging modified beam into a focused beam at a focal region, and wherein at the focal region the focused beam defines a non-planar light sheet; and
wherein the one or more focusing elements include a collimating optic and an objective lens operating together as a beam expanding subsystem which recombines all optical spectral components of the distinct beam components at a common, overlapping region, and wherein the common overlapping region represents the focal region; and
wherein the predetermined distance is used to help predict a transformation of the diverging modified beam from the planar light sheet to the non-planar light sheet.

2. The system of claim 1 , wherein the one or more focusing elements includes a mirror.

3. The system of claim 1 , wherein the mirror comprises a curved mirror.

4. The system of claim 1 , wherein the one or more focusing elements includes:
a mirror for receiving the diverging modified beam from the phase mask; and
the objective lens being arranged for receiving the diverging modified beam after the diverging modified beam has been reflected by the mirror.

5. The system of claim 1 , wherein the optically dispersive element comprises a fixed grating or a flexible grating.

6. The system of claim 1 , wherein the optically dispersive element comprises a digital micro-mirror device (DMD) or a spatial light modulator (SLM).

7. The system of claim 1 , wherein the optically dispersive element patterns each of said distinct beam components into regions of high and low intensity.

8. The system of claim 1 , wherein the phase mask comprises a phase plate.

9. The system of claim 1 , wherein the phase mask comprises at least one of a digital micro-mirror device (DMD) or a spatial light modulator (SLM).

10. The system of claim 1 , wherein the phase mask comprises a computer generated hologram (CGH) module.

11. The system of claim 1 , further comprising an electronic controller for controlling at least one of: the laser, the optically dispersive element and the phase mask.

12. The system of claim 1 , further comprising a movable stage for supporting a material to be acted upon by the non-planar light sheet.

13. The system of claim 1 , further comprising:
a lamp for generating a light beam for illuminating a material being acted on by the non-planar light sheet;
a camera; and
a beam splitter for directing the light beam from the lamp toward the camera, wherein an output from the camera is used to image the material, in situ, being operated on by the non-planar light sheet.

14. The system of claim 1 further comprising a beam expander configured to expand the laser beam produced by the laser.

15. The system of claim 1 , further comprising a beam homogenizer for acting on the laser beam to improve an intensity uniformity of the laser beam.

16. A laser-based manufacturing system for fabricating non-planar three-dimensional layers, the system comprising:
a laser for producing a laser beam with a plurality of optical wavelengths;
an optically dispersive element for receiving the laser beam and splitting the laser beam into a plurality of distinct beam components of differing wavelengths, to form an a diverging beam, wherein each one of said plurality of beam components has spatially separated optical spectral components and the diverging beam forms a planar light sheet;
a digitally tunable phase mask separated by a predetermined distance from the optically dispersive element, and configured to receive at least one of the distinct beam components emerging from the optically dispersive element, and to generate a modified, diverging beam in accordance with a desired non-planar light sheet;
a controller for controlling the digitally tunable phase mask; and
a focusing subsystem including a mirror and an objective lens configured to receive the modified, diverging beam emerging from the digitally tunable phase mask and to focus the modified, diverging beam into the desired non-planar light sheet; and
wherein the focusing subsystem includes a collimating optic and an objective lens operating together as a beam expanding subsystem which recombines all optical spectral components of the distinct beam components at a common, overlapping region, and wherein the common overlapping region represents a focal region; and
wherein the distance separating the optically dispersive element from the digitally tunable phase mask is used to predict a transformation from the planar light sheet to the desired non-planar light sheet.

17. The system of claim 16 , further comprising a camera for imaging an operation performed using the desired non-planar light sheet on a material.

18. The system of claim 16 , wherein the digitally tunable phase mask comprises one of:
a phase plate;
a digital micro-mirror device (DMD);
a spatial light modulator (SLM); or
a computer generated hologram module.

19. The system of claim 16 , wherein the optically dispersive element comprises one of:
a fixed grating;
a flexible grating;
a digital micro-mirror device; or
a spatial light modulator (SLM).

Assignees

• Saha Sourabh
• Chen Shih Chi
• Chang Yina
• L Livermore Nat Security Llc

Inventors

• Saha Sourabh
• Chen Shih-Chi
• Chang Yina

Classifications

• B23K26/06

  Shaping the laser beam, e.g. by masks or multi-focusing · CPC title

• G02B27/106 Primary

  for splitting or combining a plurality of identical beams or images, e.g. image replication · CPC title

• B33Y30/00

  Apparatus for additive manufacturing; Details thereof or accessories therefor · CPC title

• G02B26/0833

  the reflecting element being a micromechanical device, e.g. a MEMS mirror, DMD (G02B26/0825 takes precedence; micromechanical devices in general B81B) · CPC title

• B29C64/268

  using laser beams; using electron beams [EB] · CPC title