Surface roughness meter

Claim 1

IN A SURFACE ROUGHNESS MEASURING INSTRUMENT IN WHICH THE ROUGHNESS IS MEASURED BY REFLECTION FROM THE SAMPLE THE ROUGHNESS OF WHICH IS TO BE MEASURED AT SUBSTANTIALLY NORMAL INCIDENCE OF A BEAM OF RADIATION HAVING A WAVELENGTH AT LEAST TEN TIMES AND PREFERABLY AT LEAST THIRTY TIMES AS ALONG AS THE ROUGHNESS OF THE SAMPLE, THE IMPROVEMENT WHICH COMPRISES IN COMBINATION, (A) MEANS FOR LOCATING A SAMPLE, THE ROUGHNESS OF WHICH IS TO BE MEASURED, MEANS FOR PRODUCING A CHOPPED BEAM OF RADIATION AND FOR FOCUSING IT ONTO THE SAMPLE AT SUBSTANTIALLY NORMAL INCIDENCE, (B) A SELECTIVE WAVELENGTH SINGLE-COLOR RADIOMETER POSITIONED TO RECEIVE THE FOCUSED RADIATION REFLECTED FROM SAID SAMPLE AND PROVIDED WITH MEANS FOR SELECTING A PLURALITY OF WAVELENGTH BANDS, A RADIATION DETECTOR CAPABLE OF TRANSFORMING CHOPPED RADIATION INTO AC ELECTRICAL OUTPUT, AND MEANS FOR FOCUSING SAID REFLECTED RADIATION ONTO THE RADIATION DETECTOR, (C) ELECTRONIC PROCESSING MEANS CONNECTED TO THE OUTPUT OF THE RADIATION DETECTOR AND INCLUDING AC AMPLIFYING MEANS AND RECTIFYING MEANS TO PRODUCE A DC OUTPUT IN THE FORM OF A VOLTAGE, (D) A NULL READING METER AT A PREDETERMINED POINT ON ITS SCALE, ONE END OF THE METER BEING CONNECTED TO A DC POTENTIAL AND THE OTHER END TO THE DC VOLTAGE OUTPUT FROM THE RECTIFYING MEANS, (E) MEANS FOR SWITCHING THE DC VOLTAGE TO VARIOUS CIRCUITS FOR DIFFERENT SELECTED RADIATION BAND WIDTHS, (F) MEANS FOR VARYING THE VOLTAGES AT THE OUTPUT OF SAID CIRCUITS AND MEANS FOR COMPENSATING FOR VARYING SPECTRAL REFLECTANCE OF DIFFERNT MATERIALS, (G) ATTENUATING MEANS CONNECTED BETWEEN THE OUTPUTS OF SAID CIRCUITS AND THE INPUT TO AN ATTENUATOR THE OUTPUT OF WHICH IS CONNECTED TO THE NULL METER WHEREBY SAID FIRST ATTENUATOR SERVES AS A ROUGHNESS MEASURING DEVICES.