MANUFACTURE OF OPTICAL DIFFUSERS COMPOSED OF REFLOWABLE MATERIALS

Abstract

A method of making optical diffuser elements (20) includes providing a substrate (100) composed of a polymer material and having openings (102) therein. An optical diffuser material (110) is dispensed into the openings (102), and the optical diffuser material (110) is hardened to form a sheet (200) composed of regions of the optical diffuser material (110) surrounded laterally by the polymer material. The method includes separating the sheet (200) into multiple optical diffuser elements (30) that retain their mechanical stability and optical properties when subjected to a reflow process.

Claims

1. A method comprising: providing a substrate composed of a polymer material and having openings therein; dispensing an optical diffuser material into the openings; hardening the optical diffuser material to form a sheet composed of regions of the optical diffuser material surrounded laterally by the polymer material; and separating the sheet into a plurality of optical diffuser elements.

2. The method of claim 1 wherein the optical diffuser elements retain their mechanical stability and optical properties when subjected to a reflow process.

3. The method of claim 1 wherein the optical diffuser elements retain their mechanical stability and optical properties when subjected to a temperature of at least 270° C.

4. The method of claim 1 wherein the substrate is composed of a black epoxy.

5. The method of claim 4 wherein the substrate is formed by a vacuum injection molding process.

6. The method of claim 1 wherein the optical diffuser material is dispensed by jetting.

7. The method of claim 1 wherein the optical diffuser material is an epoxy material.

8. The method of claim 1 wherein the optical diffuser material is operable to diffuse light in the visible range part of the electromagnetic spectrum.

9. The method of claim 1 further including removing excess optical diffuser material that is present outside the openings.

10. The method of claim 9 wherein the excess optical diffuser material is removed by polishing.

11. The method of claim 9 wherein the excess optical diffuser material is removed by lapping.

12. The method of claim 1 including subjecting one or more of the optical diffuser elements to a reflow process.

13. The method of claim 1 including subjecting one or more of the optical diffuser elements to a process at a temperature of at least 270° C.

14. An optical diffuser element comprising: a first epoxy operable to diffuse light in the visible range part of the electromagnetic spectrum; and a black epoxy material laterally surrounding the first epoxy material, wherein the optical diffuser element retains its mechanical stability and optical properties when subjected to a reflow process.

15. The optical diffuser element of claim 14 wherein the optical diffuser elements retains its mechanical stability and optical properties when subjected to a temperature of at least 270° C.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1 illustrates an example of an optical diffuser.

[0014] FIGS. 2A through 6B illustrate steps in an example process of manufacturing optical diffusers as shown in FIG. 1.

DETAILED DESCRIPTION

[0015] The present disclosure describes a method for manufacturing multiple optical diffusers in parallel (i.e., simultaneously) and composed of reflowable materials so that the optical elements can be incorporated more easily into devices whose manufacture occurs, at least in part, at elevated temperatures (e.g., 270° C.) when the optical element is integrated into the device or during subsequent manufacturing processes.

[0016] As shown in FIG. 1, an optical diffuser 20 includes a first section 22 that is operable to diffuse light of a particular wavelength or range of wavelengths (e.g., in the visible range part of the electromagnetic spectrum). For example, in some instances, the first section 22 is operable to diffuse light having a wavelength in the range of 400-800 nm. The first section 22 can be surrounded laterally by a second section 24 that is substantially opaque to the particular wavelength or range of wavelengths. The first section 22 can be composed, for example, of an epoxy or other polymer material. Likewise, the second section 24 can be composed, for example, of a polymer such a black epoxy.

[0017] In general terms, the method of manufacturing the diffusers includes dispensing an epoxy material for the first section 22 of the diffusers in openings of an opaque substrate composed, for example, of black epoxy. FIGS. 2A through 6B illustrate various details of the method according to a particular implementation.

[0018] As shown in FIG. 2A, a substrate 100 composed of black epoxy and having openings (e.g., rectangular-shaped through-holes) 102 is provided. The substrate 100 can be formed, for example, by a vacuum injection molding (VIM) process, as shown in FIG. 2B. In the illustrated example, a Mylar™ foil or other support 103 is placed on a first (lower) polydimethylsiloxane (PDMS) injection tool 104. A second (upper) structured PDMS injection tool 106 is brought into close proximity with the first PDMS tool 104. The second PDMS tool 106 includes cavities into which a liquid black epoxy material 108 can be injected during the VIM process. After the black epoxy material is injected into the cavities, the black epoxy material is hardened (e.g., by thermal and or UV curing). The PDMS tools 104, 106 then are separated from one another, and the resulting black epoxy substrate 100 is removed.

[0019] Next, as shown in FIG. 3A, a diffuser epoxy 110 is dispensed into the openings 102 of the substrate 100. In some implementations, the diffuser epoxy 110 is provided in the openings by a jetting process. The substrate 100 can be supported by a carrier 112 during the dispensing process. As illustrated in FIG. 3B, the result is the openings 102 in the black epoxy substrate 100 are filled with the diffuser epoxy material 110.

[0020] Next, as shown in FIG. 4, the diffuser epoxy 110 present in the openings of the substrate 100 is hardened, for example, by UV curing. The result is that the openings in the black epoxy substrate 100 are filled with the hardened (e.g. cured) diffuser epoxy material.

[0021] Typically, when the diffuser epoxy material 110 is dispensed into the openings of the substrate 100, there will be an excess 110A of diffuser epoxy material present outside the areas defined by the openings 102 (e.g., projecting beyond the upper surface of the substrate 100). The excess epoxy material 110A can be removed, for example, by polishing (e.g., lapping). Preferably, the excess material 110A is removed so that the surface of the remaining epoxy material 110B is substantially flush with the black epoxy substrate 100, as shown in FIG. 5A. The result, as shown in FIG. 5B, is a sheet 200 composed of the black epoxy substrate 100 in which multiple regions of cured diffuser epoxy 110B are embedded.

[0022] Next, as shown in FIGS. 6A and 6B, the sheet 200 is separated, for example, by dicing, into individual optical diffusers 20. The singulated diffusers 20 can be integrated into an optical module or other portable host computing device (e.g., smart phone, laptop computer, wearable device).

[0023] By using reflowable materials for the diffusers 20, the diffusers can retain their mechanical stability and optical properties even when subjected to reflow processes or other processes at elevated temperatures (e.g., 270° C. or higher).

[0024] Various modifications can be made to the foregoing description. Thus, other implementations are within the scope of the following claims.