On January 30, 2014, the US Patent & Trademark Office published a patent application from Apple titled “Transparent Fiber Composite.” Apple’s invention generally describes various embodiments that relate to relatively transparent fiber reinforced composites. Apple has been experimenting with composite materials since 2007, and in 2013 the technology giant was working on nano-silica fiber coatings. They are undergoing ongoing research for new materials to use in future devices, including wearable computers.

Click to read further details of Apple’s history in composites manufacturing. A method for forming relatively transparent fiber-resin composites is disclosed. In one embodiment, a fiber for the composite can be selected and an index of refraction related to the fiber can be determined. A sizing can be selected for application to the fiber such that an index of refraction of the sizing can be within a tolerance amount of the index of refraction of the fiber. In one embodiment, the transparent fiber-resin composite can include a glass fiber, a sizing and a resin where the sizing and the resin are selected to have an index of refraction similar to a determined index of refraction of the glass fiber. In one embodiment, the glass fiber can include less than 0.1% of iron oxide.

A method of forming a transparent fiber-resin composite by injection molding is disclosed. In one embodiment, a chopped glass fiber is selected and the index of refraction of the glass fiber is determined.

A sizing for the chopped glass fiber is selected with an index of refraction similar to the index of refraction of the glass fiber. The sizing is applied to the glass fiber and a resin is selected with an index of refraction similar to the index of refraction of the glass fiber. The glass fiber is mixed with the resin and the mixture is injection molded.