Reflective straightness detecting system that hangs down based on semiconductor laser collimation

The utility model relates to a reflective straightness detecting system that hangs down based on semiconductor laser collimation, it includes the perforator, and the perforator adopts the hollow typeof the falling T structure of axle, and its tip is surperficial corresponding to the circular arc object, and is provided with semiconductor laser and semitransparent mirror in the tip vertically extension, it is provided with a through -hole, the centre of a circle of this through -hole and semitransparent mirror's central point in same water flat line to be located the extension lateral wall, laser beam that semiconductor laser launches transmits to the semitransparent mirror after, divide into first transmitted light and first reverberation, first transmitted light shines perpendicularly atcircular arc object after on the surface through transparent dielectric, reflects back semitransparent mirror, through semitransparent mirror once more the beam splitting become second transmitted light and second reverberati