Original Publication Date: 1985-Apr-01
Included in the Prior Art Database: 2005-Feb-18
A truncated conical reflector may be added below a conventional fiber- optic ring illuminator source to provide oblique illumination for microscopy and optical inspection. Oblique illumination, in both transmitted and reflected light, is a useful technique for enhancing certain features and suppressing others. Described here is a simple, inexpensive method for obtaining such illumination. In conventional fiber ring lamps 10, the fibers are roughly directed toward a common point some distance below (Fig. 1). When positioned close to the object 12 to be illuminated (Fig. 2), virtually no light reaches the field of view. This can be improved upon by using a section 14 of a conical reflector (Fig. 3). Its apex angle is approximately 45 degrees, depending on the angle at which the fibers are set in the ring.