Light guides and manufacture of light guides
The present disclosure describes light guides and a method of manufacturing light guides that include a rectangular prism-shaped bar, a first polymer or metal cladding on four sides of the rectangular prism-shaped bar, and a second polymer cladding disposed on the first polymer cladding on the four sides of the rectangular prism-shaped bar.
1. A method of manufacturing light guides, the method comprising:
injecting a first polymer so as to cover four sides of each of a plurality of rectangular prism-shaped bars while the bars are disposed side-by-side in a vacuum injection tool;
dicing through the first polymer in regions between adjacent ones of the bars wherein, after the dicing, at least a portion of the first polymer still covers each of the four sides of the bars;
injecting a second polymer so as to cover the first polymer on the four sides of the bars; and
dicing through the second polymer in regions between adjacent ones of the bars wherein, after dicing through the second polymer, at least a portion of the first polymer forms a first cladding on the four sides of the bars, and at least a portion of the second polymer forms a second cladding on the first cladding.
2. The method of claim 1 further including separating at least one of the bars into a plurality of singulated light guides, each of which comprises a portion of the bar surrounded on four sides by the first and second claddings.
3. The method of claim 2 wherein the separating includes dicing.
4. The method of claim 1 wherein the bars have a refractive index of at least 1.7 at a wavelength of 400 nm.
5. The method of claim 1 including injecting the first polymer into: (i) regions between adjacent ones of the bars, (ii) a first space between a lower surface of each bar and a first opposing surface of a first vacuum injection tool, and (iii) a second space between an upper surface of each bar and a second opposing surface of the first vacuum injection tool.
6. The method of claim 5 including curing the first polymer, removing the bars from the first vacuum injection tool and placing the bars on a first dicing tape, and dicing through the first polymer while the bars are on the first dicing tape.
7. The method of claim 6 including injecting the second polymer into: (i) regions between adjacent ones of the bars, (ii) a first space between a lower surface of each bar and a first opposing surface of a second vacuum injection tool, and (iii) a second space between an upper surface of each bar and a second opposing surface of the second vacuum injection tool.
8. The method of claim 7 including curing the second polymer, removing the bars from the second vacuum injection tool and placing the bars on a second dicing tape, and dicing through the second polymer while the bars are on the second dicing tape.
9. The method of claim 5 including supporting each of the bars on a plurality of projections in the first vacuum injection tool and subsequently supporting each of the bars on a plurality of projections in the second vacuum injection tool.
10. The method of claim 1 wherein the bars are composed of sapphire.
11. The method of claim 1 wherein a thickness of each of the first and second claddings is in a range of 100 μm-150 μm.
12. A method of manufacturing light guides, the method comprising:
applying a metal layer so as to cover four sides of each of a plurality of rectangular prism-shaped bars;
injecting a polymer layer so as to cover the metal layer on the four sides of each bar while the bars are disposed side-by-side in a vacuum injection tool; and
dicing through the polymer layer in regions between adjacent ones of the bars wherein, after dicing through the polymer layer, at least a portion of the metal layer forms a first cladding on the four sides of the bars, and at least a portion of the polymer layer forms a second cladding on the first cladding.
13. The method of claim 12 wherein the metal layer is applied by spray coating.