Illumination of convex surfaces

Abstract

Abstract AN ARCUATE MIRROR IN THE FORM OF AN ELONGATED NARROW SECTION OF AN ELLIPSOID IS USED TO REFLECT LIGHT FROM A LIGHT SOURCE ADJACENT ONE FOCUS OF THE ELLIPSOID ONTO A CONVEX SURFACE OF A WORKPIECE ADJACENT THE OTHER FOCUS OF THE ELLIPSOID. THE MIRROR SURFACE IS NARROW TRANSVERSELY OF A PLANE INTERSECTING THE WORKPIECE BUT EXTENDS IN AN ELONGATED ARC OF UP TO 180* OR MORE IN SUCH PLANE, SO AS TO DIRECT LIGHT ONTO THE WORKPIECE SURFACE IN CONVERGING RAYS OVER A WIDE ANGLE WHICH MAY BE OF THE ORDER OF, OR EXCEED 180*. THE WORKPIECE IS VIEWED BY ONE OR MORE VIEWING SYSTEMS, AND AS SEEN THEREBY, THE WORKPIECE IS ILLUMINATED WITH UNIFORM INTENSE LIGHT WHICH IS SO DIRECTED AS TO PRODUCE SPECULAR REFLECTION FROM THE CONVEX SURFACE OVER AN EXTENDED GLARE AREA OF NARROW WIDTH, IN A PATTERN WHICH VARIES WITH THE SHAPE OF THE SURFACE AND THE DIRECTION FROM WHICH IT IS VIEWED. THE ILLUMINATION IS ESPECIALLY USEFUL IN INSPECTING OBJECTS. HAVING SPHERICAL OR OTHER THREE-DIMENSIONALLY CURVED SURFACES, AND PERMITS A SINGLE VIEWING SYSTEM TO OBSERVE DEFECTS OVER A WIDE AREA NOT POSSIBLE WITH CONVENTIONAL ILLUMINATION. ON A MEDICINAL CAPSULE, VIEWED FROM THE SIDE, THE MIRROR PRODUCES A NARROW GLARE AREA EXTENDING THE FULL LENGTH OF ITS CYLINDRICAL SIDE AND INTO ITS ROUNDED ENDS. ON ITS SPHERICAL END, VIEWED END-ON, THE MIRROR PRODUCES GLARE OVER A RADIALLY ELONGATED AREA. ON A SPHERICAL BALL, VIEWED IN A DIRECTION NORMAL TO THE PLANE OF THE MIRROR ARC, THE MIRROR PRODUCES A FULL HALF-CIRCLE OF GLARE AREA.

Inventors

• 👤 H Padgitt

Bibliographic Details