Optical Components - Continued
Right Angle Prism. A right angle prism will bend light rays through an angle of 90 degrees or 180
degrees depending on which reflecting surface is used (fig. 9-15). In basic panoramic optical systems it
is normally used to reflect light rays through a 90 degree angle.
Figure 9-15. Right Angle Prism Showing Deflection of Light Rays
Wedge. Optical wedges used in fire control instruments are prisms with two plane surfaces at slight
angles which divert the paths of light through small angles by refraction instead of by reflection (fig. 9-
16). They are used where the angle of deviation required may be a matter of fractions of seconds and it
would not be practical to produce such slight deviations by means of reflection surfaces. Wedges are
used in measurement systems of range finders and to correct or adjust the alinement of paths of light.
Figure 9-16. Light Deviations Through an Optical Wedge
Change 2 9-10