Methods and apparatuses for casting polymer products

Patent metadata

Field	Value
Publication number	US-11318692-B2
Application number	US-201816163350-A
Country	US
Kind code	B2
Filing date	Oct 17, 2018
Priority date	Oct 17, 2017
Publication date	May 3, 2022
Grant date	May 3, 2022

Abstract

An example system for molding a photocurable material into a planar object includes a first mold structure having a first mold surface, a second mold structure having a second mold surface, and one or more protrusions disposed along at least one of the first mold surface or the second mold surface. During operation, the system is configured to position the first and second mold structures such that the first and second mold surfaces face each other with the one or more protrusions contacting the opposite mold surface, and a volume having a total thickness variation (TTV) of 500 nm or less is defined between the first and second mold surfaces. The system is further configured to receive the photocurable material in the volume, and direct radiation at the one or more wavelengths into the volume.

First claim

What is claimed is:

1. A system for molding a photocurable material into a planar object, the system comprising:
a first mold structure comprising:
a first mold surface, the first mold surface comprising a planar area extending in a first plane, and
a first grating pattern defined along the first mold surface;

a second mold structure comprising:
a second mold surface comprising a planar area extending in a second plane, and
a second grating pattern defined along the second mold surface,
wherein, at the corresponding planar area, at least one of the first mold structure or the second mold structure is substantially transparent to radiation at one or more wavelengths suitable for photocuring the photocurable material;

a plurality of protrusions disposed along at least one of the first mold surface or the second mold surface; and
a plurality of recesses comprising a plurality of linear slots defined along at least one of the first mold surface or the second mold surface,
wherein at least some of the plurality of protrusions are disposed along at least one of an interior of the first mold surface or an interior of the second mold surface,
wherein a first slot of the plurality of slots extends in a first direction, wherein a second slot of the plurality of slots extends in a second direction, and wherein the first direction is not parallel to the second direction, and
wherein, during operation, the system is configured to produce a polymer film having one or more first structures defined on a first side of the polymer film and one or more second structures defined on a second side of the polymer film opposite the first side, wherein the system is configured to produce the polymer film by performing operations comprising:
positioning the first and second mold structures such that:
the first and second mold surfaces face each other with the plurality of protrusions contacting the opposite mold surface and inserting into at least some of the plurality of slots,
the first plane is parallel to the second plane,
a volume is defined by the first mold surface, the first grating pattern, the second mold surface, and the second grating pattern adjacent the corresponding planar areas, the volume corresponding to a shape of the polymer film including the one or more one first structures and the one or more second structures, and
the volume has a total thickness variation (TTV) of 500 nm or less, receiving the photocurable material in the volume, and

directing radiation at the one or more wavelengths into the volume to harden the photocurable material into the polymer film.

2. The system of claim 1 , wherein each of the first mold structure and the second mold structure has a thickness greater than 1 mm.

3. The system of claim 1 , wherein each of the first mold structure and the second mold structure has a thickness between 1 mm and 50 mm.

4. The system of claim 1 , wherein each of the first mold structure and the second mold structure has a diameter greater than 3 inches.

5. The system of claim 1 , wherein at least some of the plurality of protrusions are disposed along a periphery of the first mold surface.

6. The system of claim 5 , wherein at least some of the plurality of linear slots are disposed along a periphery of the second mold surface.

7. The system of claim 5 , wherein at least some of the plurality of linear slots are disposed along an interior of the second mold surface.

8. The system of claim 1 , wherein at least some of the plurality of protrusions have a substantially rectangular cross-section.

9. The system of claim 8 , wherein at least some of the plurality of protrusions having the substantially rectangular cross-section further comprises a respective substantially hemispherical distal end.

10. The system of claim 8 , wherein at least some of the plurality of protrusions having the substantially rectangular cross-section further comprises one or more rounded corners.

11. The system of claim 1 , wherein at least some of the plurality of linear slots have a substantially rectangular cross-section.

12. The system of claim 11 , wherein at least some of the plurality of linear slots having the substantially rectangular cross-section further comprises one or more rounded corners.

13. The system of claim 1 , wherein at least some of the plurality of protrusions are integral with least one of the first mold surface or the second mold surface.

14. The system of claim 1 , wherein at least some of the plurality of protrusions are detachable from the first mold surface or the second mold surface.

15. The system of claim 1 , further comprising a light assembly configured to emit one or more wavelengths of radiation suitable for photocuring the photocurable material.

16. The system of claim 1 , wherein the first and second mold surfaces are polished surfaces.

17. The system of claim 1 , wherein, during operation, the system is configured to position the first and second mold structures such that the volume defined has a total thickness variation (TTV) of 100 nm or less.

18. The system of claim 1 , wherein each of the plurality of protrusions has a total thickness variation of 100 nm or less.

19. The system of claim 1 , wherein each of the plurality of linear slots has a total thickness variation of 100 nm or less.

20. The system of claim 1 , wherein, during operation, the system is configured to position the first and second mold structures such that the volume has a thickness between 20 μm and 2 mm.

21. The system of claim 1 , wherein, during operation, the system is configured to direct heat into the volume.

22. The system of claim 21 , wherein, during operation, the system is configured to direct heat into the volume through the first mold surface.

23. The system of claim 22 , wherein, during operation, the system is configured to direct heat into the volume through the second mold surface.

24. The system of claim 1 , wherein, during operation, the system is configured to direct the one or more wavelengths of radiation into the volume through the first mold surface.

25. The system of claim 1 , wherein, during operation, the system is configured to direct the one or more wavelengths of radiation into the volume through the second mold surface.

26. The system of claim 1 , wherein the system comprises:
a platform extending parallel to at least one of the first mold surface or the second mold surface;
a bridge extending between the platform and at least one of the first mold structure or the second mold structure, wherein a width of the platform is greater than a width of the bridge; and
a fiducial feature disposed on the platform.

Assignees

• Magic Leap Inc

Inventors

• Chang Chieh
• Peroz Christophe
• Bhagat Sharad D
• Patterson Roy Matthew
• Klug Michael Anthony
• Carden Charles Scott

Classifications

• B29C2033/0005

  with transparent parts, e.g. permitting visual inspection of the interior of the cavity · CPC title

• B29D7/01

  Films or sheets · CPC title

• B29C33/40

  Plastics, e.g. foam or rubber · CPC title

• B29C35/0805

  using electromagnetic radiation · CPC title

• B29C39/02

  for making articles of definite length, i.e. discrete articles · CPC title