Patent ID: 8009286

Claim:
A surface inspection apparatus comprising: a light source section that outputs an optical flux having two types of wavelength, which are a short wavelength and a long wavelength, while the intensity of the flux is made variable, wherein the light source section outputs the optical flux in the ultraviolet region as the short wavelength and outputs the optical flux in the visible region as the long wavelength; an irradiation optical system that makes the optical flux having two types of wavelength outputted from said light source section, incident simultaneously or alternatively to a detected surface of a body to be detected, which is a subject of surface inspection at a predetermined incident angle; a scanning section that relatively displaces at least one of said optical flux and said body to be detected in such a manner that said optical flux scans said detected surface; a first scattering light detection optical system that guides scattering light outputted from the incident portion of said detected surface, to which said optical flux has been made incident, to a first light intensity detecting section; a regular reflection light detection optical system that guides regular reflection light outputted from the incident portion of said detected surface, to which said optical flux has been made incident, to a second light intensity detecting section; and a controlling arithmetic section that adjusts at least the intensity of the optical flux having a long wavelength outputted from the light source section based on a wavelength of optical flux outputted from the light source section and an output from the first light intensity detecting section, wherein said controlling arithmetic section is constituted so as to compare the output from said first light intensity detecting section in irradiating the optical flux having a short wavelength, with the output from said first light intensity detecting section in irradiating the optical flux having a long wavelength, and then, identify a signal that appears only in the output from said first light intensity detecting section in irradiating the optical flux having a long wavelength, as a detected signal from an internal subject, and further adjusts the intensity of the optical flux having a long wavelength, and then calculates a disappearance level near a point where the detected signal from the internal subject disappears, further the controlling arithmetic section sets the first intensity of the optical flux having a long wavelength to a level higher than the disappearance level, and measures a subject inside the body to be detected based on the output from the first light intensity detecting section obtained by the optical flux having a long wavelength of the first intensity.