Patent ID: 7595479

Claim:
A tilt detecting method, comprising: (A) setting a tilt detector on a subject, and the tilt detector comprises a light-detecting unit and a light-permeable unit, wherein the light-detecting unit comprises a body, and a window formed on the body; the light-permeable unit comprises a chamber, an opaque fluid filling the chamber, and a light-permeable substance positioned in the opaque fluid, wherein the chamber comprises a first sidewall connected with the window and pervious to light, a second sidewall opposite to the first sidewall and pervious to light; the light-permeable substance touches the first sidewall and the second sidewall in the chamber and moves along a slope of an subject; (B) detecting a facula location with the light-detecting unit comprising a window, wherein when a beam is emitted to the window via the light-permeable substance, outputting at least one signal corresponding to the facula location, and the facula location in the window is shifted according to the movement of the light-permeable substance; and (C) determining a tilt state of the subject in accordance with the result of calculation of the at least one signal.