Optical sensor for measuring inclination angles

An angle sensor adapted for 360 degrees rotation about an axis to provide output indications of angles between a reference axis and an axis about which said angle sensor rotates, comprising:

• a vessel for containing a fluid, said vessel having opposing end walls through which the axis of rotation passes;
• an optical emitter for emitting energy and an optical detector for detecting the energy, each fixed to a respective said end wall of the vessel where said axis of rotation passes therethrough, and for movement thereof with the vessel;
• and
• said fluid filling the vessel less than full and having a boundary surface for modifying an intensity characteristic of the energy in correspondence with angular orientation of the sensor with respect to the reference axis, whereby said detector detects the energy characteristics and produces an output corresponding to the angular orientation of the sensor and is independent of the rotational orientation of the angle sensor.

An angle sensor adapted for rotation about an axis and providing output indications of angular orientations with respect to a reference, comprising:

• a vessel for containing a fluid, said vessel having a cylindrical shape for rotating about the axis, and having end caps fastened to the vessel for providing an enclosure;
• an optical emitter for emitting energy and an optical detector for detecting the energy, each fixed to a respective said end cap of said vessel in alignment with said axis for rotational movement thereof with the vessel;
• and
• said fluid being of the type for reflecting the emitted energy from the emitter and received by the detector in an intensity corresponding to an angular orientation of the vessel between the reference and the axis of rotation, whereby the detector produces a continuous angle output that changes only with a change in an angle between the reference and the rotational axis of the vessel, and is independent of the rotational position of the angle sensor.