LASER TYPE SURFACE INSPECTION APPARATUS

• Main Authors: CHIBA SHUICHI, IIZUKA NOBUYUKI, HACHIKAKE YASUO
• Format: Patent
• Language: English
• Published: 28.11.1986
• Subjects: INFORMATION STORAGE; INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER; INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIRCHEMICAL OR PHYSICAL PROPERTIES; MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PURPOSE:To obtain easy-to-maintain surface inspection apparatus, by making the hole of a holed mirror larger than the laser beam diameter on the optical axis of a projection optical system concentrically with the optical axis thereof while the mirror surface is set to cross the optical axis slantly. CONSTITUTION:A laser light (a) is reflected 2 to be converged 3 and irradiates the point A where it was reflected 6 passing through a holed mirror 4 and a holed lens 5. The center hole diameter of the mirror 4 and the lens 5 is made larger than the beam diameter and concentric with the optical axis, causing no effect. The normal reflection component (e) along at the point A reverse through the projected light path to return to a laser oscillator 1. The scattered components (h) and (i) are reflected 6 and diffused to be incident into the holed lens 5, converged at the part except for the center hole and then, reflected at the part except for the center hole of the holed mirror 4 inclined by 45 deg. from the projection optical axis to be gathered at a light-receiving surface of an element 7. This enables miniaturization with a simple construction, thereby making the maintenance and adjustment eliminating a spatial filter.