JVC Model 200 service manual Arc Lamp Light Path

Chapter 2---System Description

Combining (4P) Prism: The combining prism consists of separate prisms that polarize each of the three high intensity signals and direct them toward the projection lens.

Projection Lens: The Projection Lens picks up the high intensity image from the Combining Prism and transmits it to the projector screen.

2.2.2 Arc Lamp Light Path

The Arc Lamp assembly produces the high intensity light used to transmit bright images to the screen. It consists of a Xenon Arc Lamp containing xenon gas under pressure, an ignitor assembly that provides the spark to light the arc lamp, and a laser power supply to provide the boost voltage to the Ignitor. An exhaust fan helps keep the arc lamp cool. The description below follows the sequence of the light path. (See Figure 2-1).

Ignitor and Laser Power Supply: The Laser Power Supply provides a boost voltage through a spark gap to the Ignitor circuit which then provides a momentary High Voltage, (32,000 volts), to excite the xenon gases inside the Xenon Arc Lamp. After the arc lamp ignites, it is maintained ON by high current and low-voltage (approximately 37.5 amps and +20 volts). The arc lamp Ignitor and Laser Power Supply are mounted next to the arc lamp, inside the Arc Lamp assembly housing.

WARNING!!! The Xenon Arc Lamp produces high intensity white, ultraviolet and infrared light capable of severe eye injury. Never look directly at or touch the Xenon Arc Lamp.

Service should be performed by Hughes-JVC certified technicians only.

Xenon Arc Lamp/Condensing Lens: High pressure, ionized xenon gas supports a high-current electrical arc to produce the intense, white light used in the Model 200 projector. The high intensity light output from the Xenon Arc Lamp is reflected by an elliptical metal reflector to a Condensing Lens where the light beam is condensed and directed to the Cold Mirror.

Cold Mirror/IR Filter and Ultraviolet Filter: The arc lamp light beam passes through the Condensing Lens to the Cold Mirror and Infrared Filter which removes most of the IR light, then through the Ultraviolet filter which removes most of the UV light. The light beam then proceeds toward the Dichroic Mirror Assembly. In this manner most of the IR and UV light is filtered out before the light beam enters the more sensitive portions of the optics, leaving only the visible portion.

Dichroic Mirror Assembly: The condensed and filtered white light beam enters the Dichroic Mirror Assembly which separates (dichroic mirrors reflect only one color and pass all others) the

2-4 Model 200 Service Manual