Optical measurement device

Abstract

A white light confocal optical measurement device capable of detecting abnormalities in a received light waveform; the optical measurement device includes: a light source; an optical system; a light receiving unit; and a processor configured to compute the distance from the optical system to the measurement object on the basis of a received light intensity of the wavelength components received in the light receiving unit. The processor compares a received light intensity of a wavelength component to a reference value for the wavelength component for a plurality of wavelength components in a waveform representing the light received, and detects an abnormality in the received light waveform when the amount of change in the received light intensity compared to the reference value therefor is greater than or equal to a predetermined threshold for any wavelength component in the plurality of wavelength components.57544739

What is claimed is: 
     
         1 . An optical measurement device comprising:
 a light source configured to emit illumination light including a plurality of wavelength components;   an optical system configured to introduce an axial chromatic aberration into the illumination light from the light source and to receive reflection light reflecting from a measurement object where at least a portion of the measurement object lies along a line extending from the optical axis of the optical system;   a light receiving unit configured to separate the reflection light received at the optical system into wavelength components and thereby receive the light having the wavelength components; and   a processor configured to compute the distance from the optical system to the measurement object on the basis of a received light intensity of the wavelength components received in the light receiving unit;   the processor compares a reference value for a received light intensity and the received light intensity of a wavelength component outside a wavelength domain equivalent to a measurement range used to measure the displacement of the measurement object, and detects an abnormality in a received light waveform representing the received light intensity when the amount of change in the received light intensity compared to the reference value therefor is greater than or equal to a predetermined threshold.   
     
     
         2 . The optical measurement device according to  claim 1 , wherein the processor provides notification of the abnormality when the abnormality is detected. 
     
     
         3 . An optical measurement device comprising:
 a light source configured to emit illumination light including a plurality of wavelength components;   an optical system configured to introduce an axial chromatic aberration into the illumination light from the light source and to receive reflection light reflecting from a measurement object where at least a portion of the measurement object lies along a line extending from the optical axis of the optical system;   a light receiving unit configured to separate the reflection light received at the optical system into wavelength components and thereby receive the light having the wavelength components; and   a processor configured to compute the distance from the optical system to the measurement object on the basis of a received light intensity of the wavelength components received in the light receiving unit;   the processor compares a reference value for a received light intensity and the received light intensity of a wavelength component outside a wavelength domain equivalent to a measurement range used to measure the displacement of the measurement object, and determines, on the basis of the result of comparison, whether or not the distance to the measurement object can be normally measured.   
     
     
         4 . An optical measurement device comprising:
 a light source configured to emit illumination light including a plurality of wavelength components;   an optical system configured to introduce an axial chromatic aberration into the illumination light from the light source and to receive reflection light reflecting from a measurement object where at least a portion of the measurement object lies along a line extending from the optical axis of the optical system;   a light receiving unit configured to separate the reflection light received at the optical system into wavelength components and thereby receive the light having the wavelength components; and   a processor configured to compute the distance from the optical system to the measurement object on the basis of a received light intensity of the wavelength components received in the light receiving unit;   the processor compares a reference value for a received light intensity and the received light intensity of a wavelength component outside a wavelength domain equivalent to a predetermined measurement range used to measure the displacement of the measurement object, and   the processor detects an abnormality in a received light waveform representing the received light intensity when the difference between the received light intensity and the reference value is greater than a predetermined threshold, whereas the processor computes the distance to the measurement object when the difference between the received light intensity and the reference value is less than the predetermined threshold.   
     
     
         5 . The optical measurement device according to  claim 4 , wherein the abnormality is an abnormality relating to reflection of a portion of the illumination light in the optical system.