Noninvasive load and pressure sensor system utilizing the principle of refraction of light through a compressible fluid

摘要

The present noninvasive load and pressure sensing system makes use of a transparent pressure vessel that is filled with a compressible fluid, whose refractive index changes as a function of the pressure applied to the compressible fluid to redirect the path of a light beam that is transmitted through the transparent pressure vessel. An incident beam of coherent monochromatic light is applied to a transparent segment of a wall of the transparent pressure vessel, where this incident light beam is refracted by the compressible fluid contained in the transparent pressure vessel. The refracted light beam traverses the transparent pressure vessel and exits the transparent pressure vessel at a point along the opposite wall of the transparent pressure vessel as determined by the refractive index of the compressible fluid, which is determined by the pressure of the compressible fluid. The pressure of the compressible fluid is controlled by using a scale comprising a compressible bladder that is fluidically connected to the transparent pressure vessel. The weight placed on the scale varies the pressure of the compressible fluid and thus its refractive index. Thus, by measuring the exit point of the refracted light beam on the wall of the transparent pressure vessel the pressure, and thus the weight of the object placed on the scale, can be determined.