This Thursday, the US Patent and Trademark Office approved an Apple patent for the "Flexible TRS Connector," which describes many design schemes for headphone connectors, in which the connector and sleeve will use flexible materials. By using flexible or elastic parts, the plugs described in Apple's patent can withstand adaptive bending, and currently available plugs on the market can be damaged when bent.

The example image used in the patent is very similar to the 3.5mm earphones standard on iPhone, which include a conductive head, a conductive sleeve, and two conductive rings. The dielectric material that separates audio, microphone, and ground signals between conductive areas. The signals between conductive areas are transmitted to the internal wire components and transmitted to the sound unit through cables. These TRRS connectors are very fragile due to their structural design and are prone to damage when inserted or removed due to excessive force or misalignment.

The plug described in Apple's patent uses flexible elastomers or thermoplastic elastomers, which will allow users to avoid damage when accidentally bending the plug. These materials replace dielectric insulating materials, and in some examples, the internal components that run through the entire sleeve can be coated with elastomers in a conductive layer. This flexible plug can withstand slight bending and, in some cases, can effectively protect the headphone plug.

Every generation of iPhone is trying to get thinner, and on the latest iPhone 5, the 3.5mm headphone jack almost occupies the entire thickness of the phone. At present, the headphone jack has become a bottleneck in limiting the thickness of mobile phones. It is unclear whether Apple will apply the patented technology on iOS devices, but as smartphones become thinner, Apple may choose a 2.5mm headphone jack.