These three articles are a little outdated, but introduced here for reference purpose.
All public teardowns have identified Balda, which produces high-tech assemblies from high-performance plastics and electronic components at its headquarters in Bad Oeynhausen, Germany, as the supplier of the touchscreen display module for the iPhone. But a closer look reveals that Balda's Taiwan-based partner, TPK Holding, with which Balda formed a joint venture to get into touchscreen production, is really behind the module.
Under the Hood: Inside the Apple iPhone, 07/01/2007
The iPhone's debut was immediately met with cheap clones designed to capitalize upon the hype. Semiconductor Insights's team went inside two of those clones and was surprised at first by how bad they were, but then later by how close they came to emulating—and possibly surpassing—the original
Analysts at Portelligent did a quick overnight teardown of the Apple iPhone and uncovered yet more semiconductor design wins, while succumbing to an unusually high level of giddiness over the simplicity and grace of the device and its software-enabled user interface.