User`s manual

doc-3302-2 OverView mDR50-DL (May 2003) 3-3
3.2 The En trails of the Dark Box
The dark box houses the projection unit with the a single-DMD™ chip, color filter system, illumi-
nation and projection optics, the illumination unit (dual lamp system), and a cooling system.
Via a mirror, the image is projected onto the rear of the screen.
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Figure 3-2
1 Projection Unit
2 Illumination system (dual lamp system)
3 Power block
4 Filter
5 Dark Box
6 Mirror
7 Screen
 Dual Lamp System
The light of a 120 Watt UHP™ lamp illuminates via a transmissive color wheel the DMD.
The projection engines has a dual lamp system and can be operated in three operation modes:
Hot Standby, Cold Standby, Auto Switch mode.
In
Hot Standby both lamps are on. In case of a lamp failure, the light output of the other lamp
is immediately switched to illuminate the optics, and there is no noticeable effect on the dis-
played information: no loss of information, no impact on quality. Switching time is about half a
second.
In
Cold Standby mode the second lamp is only switched on in case a failure occurs with the
active lamp. Since the second lamp needs about one minute to reach a stable operating tem-
perature, at the beginning the display will have reduced brightness. The contents of informa-
tion, however, is available nearly without any interrupt.
Auto Switch mode is a special version of the cold standby mode: the lamps are active in turns:
every 500 hours the light path is illuminated by the other lamp. Since the lamp is switched on
some minutes in advance, the takeover of the other lamp is nearly not noticeable