Chapter 2—Functional Descriptions
Optical Subassemblies
Cold Mirror
The Cold Mirror lets most of the infrared light pass through and reflects the rest of the light toward the prism through an ultraviolet filter/condensing lens, dichroic mirrors and
The infrared light is absorbed in a series of
CAUTION! Cold mirrors absorb IR light and can get very hot!
Ultraviolet Filter and Condensing Lens
The arc lamp light beam reflected off the cold mirror passes through the Ultraviolet Filter/Condensing Lens that removes most of the Ultraviolet light and condenses the light beam. Therefore, most of the infrared and ultraviolet light is filtered out before the beam enters the more sensitive portions of the optics, leaving only the visible portion. Without these filters, the infrared light would overheat the prisms and the ILA® assemblies, and the ultraviolet light would damage the ILA® assemblies and be hazardous to personnel.
Dichroic Mirrors and Down-Steering Mirrors
The condensed light beam strikes the first dichroic mirror that is designed to pass red and green light but reflect blue light. The blue light is reflected to a down- steering mirror which reflects it again directly to the prism in the blue system. The red and green light travel on to the next dichroic mirror that passes the red light and reflects the green light to the
CAUTION! Do not attempt to realign any mirrors. They require the use of a complex laser beam alignment fixture.
2.8 Image Light Amplifier
A closer examination of the output side of the ILA® assembly as illustrated in Figure
Visible light from the arc lamp passes through dichroic mirror assemblies and is then reflected into a prism assembly that polarizes the light horizontally. The
HJT Model 330, 340SC, and 370SC Service Manual |
