Development And Design Of Polarized Laser Acupuncture Equipment Based On Liquid Crystal Modulator

Laser acupuncture is one kind of therapy method that using low intensity laser beams instead traditional acupuncture needles to irradiate acupuncture points in order to get a therapy aim by produced bio-stimulus effects. It has many merits, such as having more effective particular physical therapy effects than traditional acupuncture, no invasion, no intersectional infection risk, more acceptable by patients and so on. The coherent and polarized characteristics of laser are regarded as the key points of producing particular physical therapy effects to human body, In this paper, a polarized laser acupuncture equipment (PLAE) based on the liquid crystal modulator (LCM) has been designed.According to medical research requirement and clinical demand, the paper first proposes two functions of PLAE: polarization state switch function and momentarily illumination intensity modulation function; then it explicates the structure of PLAE around the realization of the two functions. The first function is based on electrically controlled birefringence effect of liquid crystal. Laser polarization state corresponds to modulation phase generated by LCM is controlled by the peak-to-peak voltage value of 1K rectangular wave outputs by the control circuit of the PLAE. The control circuit system is based on the FPGA chip which can be programmed by some hardware languages such as VHDL. Comparing to other laser acupuncture apparatuses which using laser needles with fixed polarization state, the PLAE in this paper is an innovation with ability to change polarization state of laser needles by electrical automation. In order to simulate traditional acupuncture skills by variation of laser intensity, momentarily illumination intensity modulation function has been designed for PLAE, which is indirectly achieved by PWM method.In this paper, after presentation the structure of PLAE, there are some tests for the equipment. The results show that the polarization state switch function is achieved very well. The PLAE can emit laser needles with any polarization state in certain precision range. The liner polarized laser, lift-hand circularly polarized laser, right-hand circularly polarized laser and±π/4 elliptically polarized laser send by the PLAE are nearly perfect. In the other hand, the shape of modulating illumination intensity wave is very similar with the shape designed by the VHDL language beforehand. So it is proved that the second function is also achieved successfully. At last, the paper enhanced the practicability of the PLAE by increasing output laser needles from one to four and improving the control circuit.