Polymer Object Optical Fabrication Process

• US 20070108644A1
• Filed: 11/17/2006
• Published: 05/17/2007
• Est. Priority Date: 11/17/2005
• Status: Active Grant

• Current Assignee: Poof Technologies, LLC
• Original Assignee: Poof Technologies, LLC
• Inventors: Cregger, Robert
• Granted Patent: US 7,778,723 B2
• Time in Patent Office: Days
• US Class Current: 264/1.370
• CPC Class Codes: B29C 64/106 using only liquids or viscous materials, e.g. depositing a continuous bead of viscous material
• CPC Class Codes: B29C 64/135 the energy source being concentrated, e.g. scanning lasers or focused light sources
• CPC Class Codes: B33Y 10/00 Processes of additive manufacturing
• CPC Class Codes: B33Y 30/00 Apparatus for additive manufacturing; Details thereof or accessories therefor
• CPC Class Codes: B33Y 50/02 for controlling or regulating additive manufacturing processes
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing

Abstract

High-volume mass-production and customization of complex three-dimensional polymer and polymer-derived-ceramic microstructures are manufactured in a single step directly from three-dimensional computer models. A projection based non-degenerate two-photon induced photopolymerization method overcomes the drawbacks of conventional one and two-photon fabrication methods. The structure includes dual, synchronized, high-peak power, pulsed femtosecond and picosecond lasers combined with spatial light modulation. Applications include high-resolution rapid prototyping and rapid manufacturing with an emphasis on fabrication of various Micro-Electro-Mechanical Systems (MEMS) devices, especially in the area of MEMS packaging.

Claims

1. A method for fabricating three-dimensional micro-structures directly from computer models, comprising the steps of:

providing a container at least a part of which is optically transparent;

placing a photoreactive material into the container so that said photoreactive material is accessible by laser light;

modifying said photoreactive material by non-degenerate two-photon absorption.

2. The method of claim 1, wherein said modifying step includes patterned modification to produce solidification of said photoreactive material in accordance with said pattern.

3. The method of claim 1, wherein said modifying step includes patterned modification to produce desolidification of said photoreactive material in accordance with said pattern.

4. The method of claim 1, wherein said modifying step includes patterned modification to produce modification of the index of refraction of said photoreactive material in accordance with said pattern.

5. The method of claim 1, further comprising the steps of:

providing an array of controllable pixel elements;

directing femtosecond laser pulses onto the array of pixel elements so that said array of pixel elements generates a pulsed patterned source light having a wavelength selected to induce non-degenerate two-photon polymerization;

providing a first optical projection system for projecting said pulsed patterned source light;

providing a pulsed laser light having a wavelength selected to induce non-degenerate two-photon polymerization;

providing a second optical projection system for projecting said pulsed laser light;

synchronizing said pulsed patterned laser source light and said pulsed laser light;

aiming said pulsed patterned source light so that said pulsed patterned source light travels through an optically transparent part of said container into the photoreactive material and focuses inside said photoreactive material, forming a first thin, flat sheet of source light;

directing picosecond pulsed laser light and focusing said picosecond laser pulses into a flat, thin sheet of laser light that intersects the flat, thin sheet of pulsed patterned source light from the array of pixel elements, said intersection creating a fabrication region, with the respective focal planes of said intersecting sheets of light overlapping, such that the flat, thin sheet of laser light intersects the flat, thin sheet of pulsed patterned source light perpendicular to the projected source so that preselected regions of the photoreactive material are cured at said fabrication region;

directing said container having said photoreactive material therein through said intersecting focal planes at an angle less than the critical angle of a material of which said container is made and of said photoreactive material;

whereby synchronized overlapping pulses operating at two different wavelengths of preselected energies meet the combined energy requirements necessary to achieve non-degenerate two-photon absorption in the fabrication region within said photoreactive material.

6. The method of claim 1, further comprising the step of:

monitoring real-time velocity of the container through the fabrication region with a feedback velocity-monitoring sensor.

7. The method of claim 6, further comprising the steps of:

sending electronic data for each image pattern projected from the controllable pixel element;

providing a computer control system for throttling the refresh rate of the controllable pixel array according to velocity feedback data obtained from said velocity monitor sensor.

9. The method of claim 6, further comprising the steps of:

providing a computer control system for controlling the laser repetition rate, the light path length, and the controllable pixel array in accordance with velocity feedback data obtained from said velocity monitor sensor.

10. The method of claim 6, further comprising the step of:

providing a computer-executable program for extracting a series of slices of a three-dimensional computer model data into a series two-dimensional image files that are compatible with the controllable pixel elements.

11. The method of claim 10, further comprising the steps of:

sequentially sending the sequence of two-dimensional images extracted from the three-dimensional computer model file to the controllable pixel array allowing projection of the slices of the computer model file into the photoreactive material as the photoreactive material translates through the fabrication region at a velocity determined by the photoreactive cure time of the photoreactive material and the real-time velocity feedback data.

8. The method of clam 6, further comprising the steps of:

providing a computer control system for altering the conveyor speed in accordance with velocity feedback data obtained from said velocity monitor sensor.