FREQUENCY SHIFTER AND OPTICAL TYPE DISPLACEMENT MEASURING APPARATUS USING THE SAME

摘要

PURPOSE: To enable detection of displacement information at a high accuracy even when the speed of a moving object is low by putting a temperature uniformity means closely at least on a part of a photoelectric element. CONSTITUTION: A laser light emitted from a laser 1 is turned to a parallel luminous flux 3 with a collimator lens 2 and divided into luminous fluxes 5a and 5b with a beam splitter 4. The luminous fluxes 5a and 5b are reflected with mirrors 6a and 6b, then admitted into an photoelectric element 10 and the luminous flux 5a alone is subjected to a frequency shifting with a frequency shifter 101. Thereafter, the luminous fluxes 5a and 5b are reflected with mirrors 6e and 6d and then incident into a moving object 7. Scattered light from the moving object 7 is detected with a photo detector 9 through a condenser lens 8. The luminous fluxes 5a and 5b are passed through the same photoelectric element 10 to be stabilized structurally. Moreover, a heat conductor 12 contacts the top and bottom of the photoelectric element 10 through a silicone rubber 13 to prevent possible temperature difference and temperature gradient thereby securing stability against heat.