Design of adjustable measuring tool for posterior auricular area

Abstract

This research project is a collaboration between TUDelft, UPPS Fieldlab, and Made4eyes, a company that produces made-to-fit eyewear.
In order to design a frame correctly, it is essential having a 3D head scan upon which the frame can be molded. The temple tips are crucial components that contribute to the frame's comfort and stability. Therefore it is fundamental to identify the curvature of the head behind the ear to model the temple tips accordingly.

This area resulted difficult to 3D scan due to its position, the projected shadow of the ear, the limitations of the technology currently in use (occipital sensor scanner II), and the occasional involuntary movements of the subjects during the scan.
Several methods have been tested to retrieve the posterior auricular area's curvature, including 3D scanning (using Artec Eva lite, Artec Spider, and 3Shape's Intraoral scanner Mark II), taking silicone molds, and combining both methods.

The 3D scan results were either not accurate enough or presented problems during the elaboration phase (misalignment between the surfaces). The area corresponding to the attachment between the ear and the skull was not captured by any of the scanners.
It was concluded that the most effective way to retrieve data would be by creating a mold with an embedded reference system that could later be 3D scanned.

The developed solution is "flex" an adjustable frame that functions as a measuring tool due to the flexibility of its temple tips. The adjustability features (360° hinge and extendable temple tips) make this tool adaptable to a diverse user group.
Once the temple tips curvature mold has been taken, the frame can be removed, and 3D scanned. The information retrieved is necessary to design comfortable and functional temples.