초록 ▼

Surface roughness is tested by an optical probing method which involves scanning a beam of light from a laser over a specimen workpiece via a semi-reflecting mirror and a cylindrical lens and detecting the specular component of the light reflected back through the lens and the semi-reflecting mirror

Surface roughness is tested by an optical probing method which involves scanning a beam of light from a laser over a specimen workpiece via a semi-reflecting mirror and a cylindrical lens and detecting the specular component of the light reflected back through the lens and the semi-reflecting mirror to a photomultiplier the output from which is fed to an electronic processor circuit which derive a numerical value representing the mean intensity of the reflected radiation. A workpiece to be tested is then substituted for the specimen workpiece and a new numerical value derived. The two numerical values are compared, as by division or subtraction to obtain an output signal representing the relative surface roughness of the workpiece under test with respect to that of the specimen.

대표청구항 ▼

Apparatus for testing the surface roughness of a workpiece which has been subjected to a mechanical working operation, comprising in combination, a support for the workpiece to be tested, a laser radiation source, a first optical system positioned in the path of radiation from said radiation source

Apparatus for testing the surface roughness of a workpiece which has been subjected to a mechanical working operation, comprising in combination, a support for the workpiece to be tested, a laser radiation source, a first optical system positioned in the path of radiation from said radiation source and operating to direct the beam of radiation emitted by said source onto the surface of a workpiece to be tested mounted on said support, means for relatively displacing said support and said beam of radiation whereby to scan said beam of radiation over the region of interest of said surface of said workpiece under test, a photomultiplier, a second optical system positioned in the path of the specular component of radiation reflected from each point of said scanned region of said surface of said workpiece under test and operating to direct said specular component of the reflected radiation to said photomultiplier whereby to obtain at the output of said photomultiplier an electrical signal indicative of the intensity of said component, an electronic processor cirecuit connected to the output from said photomultiplier, said processor circuit operating to derive a numerical value corresponding to the mean level of said output signal and to provide a numerical indication of at least one of the ratio and the difference between said numerical value and a reference numerical value, said first and second optical systems together comprise: a semi-transparent mirror positioned to deflect by 90°radiation incident thereon from said laser radiation source, a cylindrical lens, a first reflector positioned in the path of radiation reflected from said semi-transparent mirror so as to deflect it to said cylindrical lens, said cylindrical lens having its focal line passing through the point on said first reflector at which incident radiation from said semi-transparent mirror impinges and having its optical axis normal to the surface of said workpiece to be tested, a second reflector positioned to deflect towards said photomultiplier the specular component of reflected radiation from each point of the scanned zone of the said surface, which arrives at said second reflector after having passed through said cylindrical lens, and said means for relatively displacing said support and said beam of radiation comprise means for causing said first reflector to oscillate about an axis parallel to the surface of said workpiece to be tested and passing through the focus of said cylindrical lens.