Stereolithographic apparatus and method of use

• US 5,247,180 A
• Filed: 12/30/1991
• Issued: 09/21/1993
• Est. Priority Date: 12/30/1991
• Status: Expired due to Term

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Nelson, William E., Mitcham, Larry D.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): NGUYEN, KIET TUAN
• Application Number:
  US07/814,859
• Time in Patent Office: 631 Days
• Field of Search: 250/492.1, 264/22, 425/174, 425/174.4, 346/108, 346/160, 364/522, 356/121, 356/375
• US Class Current: 250/492.1
• CPC Class Codes: B29C 2035/0838 using laser
• CPC Class Codes: B29C 64/129 characterised by the energy source therefor, e.g. by global irradiation combined with a mask
• 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: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: G03F 7/0037 Production of three-dimensional images
• 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 7/70416 2.5D lithography

Abstract

A stereolithographic apparatus is disclosed comprising a vat, a working surface in the vat, an elevating mechanism for controlling the level of liquid within the vat relative to the working surface, an illumination source for emitting radiation, and an area array deformable mirror device. The illumination source emits radiation which is operable to harden a stereolithographic liquid, while the deformable mirror device is operable to reflect the incident radiation onto the surface of the liquid. The deformable mirror device can harden an entire lamina of liquid in one brief exposure interval increasing throughout without sacrificing resolution.

Claims

1. A stereolithographic apparatus comprising:

a vat for receiving a stereolithographic liquid;

a working surface within the vat;

an elevating mechanism for controlling the level of the liquid in the vat relative to the working surface; and

at least one exposure head, each exposure head comprising an illumination source for emitting radiation, the radiation operable to harden the liquid, and an area array deformable mirror device responsive to applied signals for selectively reflecting the radiation to form an image on the surface of the liquid, wherein said exposure head is movable in two dimensions.

2. The stereolithographic apparatus of claim 1 further comprising a lens for magnifying the image of the area array deformable mirror device.

3. The stereolithographic system of claim 1 further comprising a positioner for moving the exposure head in two dimensions.

4. The stereolithographic apparatus of claim 3 further comprising a lens for magnifying the image of the area array deformable mirror device.

5. The stereolithographic apparatus of claim 1 wherein the elevator raises the liquid relative to the working surface.

6. The stereolithographic apparatus of claim 1 wherein the elevator lowers the working surface into the liquid.

7. The stereolithographic apparatus of claim 1 wherein the liquid is a resin containing a photoactive agent.

8. The stereolithographic exposure head of claim 1 wherein the liquid is a polymer containing a photoactive agent.

9. A stereolithographic exposure head for use with a stereolithographic apparatus, the exposure head comprising:

a plurality of mirrors individually responsive to input signals, the mirrors operable to reflect incident radiation along a plurality of optical pathways, the mirrors forming a n×

m matrix;

an illumination source for emitting radiation incident upon the mirrors, the radiation operable to harden a stereolithographic liquid;

control circuitry responsive to input data operable to select one of the plurality of pathways along which each of the mirrors will reflect incident radiation to form an image, wherein said data selecting one of the pathways forms a cross-sectional image.

10. The stereolithographic exposure head of claim 9 wherein said plurality of pathways comprise two pathways.

11. The stereolithographic exposure head of claim 9 further comprising a lens for magnifying the image of the plurality of mirrors.

12. The stereolithographic exposure head of claim 9 further comprising a positioner for moving the head in two dimensions.

13. A method of forming a model of cured resin comprising the steps of:

applying a thin film of stereolithographic liquid to a surface;

illuminating a plurality of deformable mirrors with radiation operable to cure the liquid resin; and

deflecting certain of the mirrors such that a portion of the radiation is directed to the film of liquid, the directed radiation curing a portion of the resin, the portion of the resin forming at least part of a lamina of the model; and

repeating said steps to form said model in successive layers.

14. The method of claim 13 further comprising the step of sequentially repeating the applying, illuminating and deflecting steps until the sequence of laminas forms the model.

15. The method of claim 13 further comprising the steps of:

moving the plurality of deformable mirrors with respect to the thin film; and

curing the uncured portions of the lamina of the model.

16. The method of claim 15 further comprising the step of sequentially repeating the applying, illuminating, deflecting, moving and curing steps until the sequence of lamines forms the model.