A transparent spherical microscope stage to realize tracking and omni-directional imaging with 6 degrees of freedom*

To achieve an observation stage with 6 degrees of freedom, a specimen was placed at the center of a transparent sphere or polyhedron. This novel configuration enables not only positional tracking, but also posture tracking, as well as scanning on three rotational axes. After discussing the solution space for spherical and polyhedral shapes and the mechanisms available to achieve 6-DoF, we demonstrate our invention with two proof-of-concept prototypes: (1) the polyhedron-gimbal, which allows simultaneous rotation of pitch, yaw, and roll, and (2) an actuated sphere-retractable axis version, which uses friction for pitch and roll, and a gear mechanism for yaw. To the best of our knowledge, this is the first example of omni-directional imaging suitable for 3D stereomicroscopy of biological organisms. In the future, it will be applied to the monitoring of 3D cellular growth in various conditions. Video abstract—https://youtu.be/kJLVPvKqaOc