| 摘要 |
PURPOSE: To prevent an optical sensor from being damaged by diffusing through a concave lens a laser beam branched with a beam splitter, passing it through a pin hole of a shield and measuring the intensity of the laser beam with the optical sensor. CONSTITUTION: A laser beam 11 is converged with a condensing lens 2 so as to machine an object 4 to be worked. A part of the laser beam 11 is vertically retracted with a beam splitter 3 arranged between the condensing lens 2 and the object 4, so that a branched laser beam 12 is formed. The optical path of the branched laser beam 12 is diffused with a concave lens 5, which lowers the density of the energy. The branched laser beam 12 passes through the pin hole 6a of a shield 6, with the energy quantity further lowered. The intensity of the energy of the branched laser beam 12 is measured with an optical sensor 7. If the temperature of the condensing lens 2 varies during machining and thereby changes the focal distance, the measurement of the optical sensor 7 also changes, leading to the detection of abnormality. Since the optical sensor 7 is irradiated with a weak laser energy, it is not damaged. |
