Electrohome VistaGRAPHX 2500, Руководство пользователя

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INSTALLATION & SETUP
VistaGRAPHX 2500 User's Manual
2-3
Front Screen Installations
There are two basic screen types: flat and curved. The choice between a flat
screen or a curved screen is dependent on audience viewing angle and screen
gain. There is always a trade-off between viewing angle and gain. Viewing
angles for both screen types are illustrated in Figure 2-1 and Figure 2-2 (plan
views).
Flat screens offer a gain of about 1 with a viewing angle just less than 180°.
Incident light reflects equally in all directions so the audience can see the display
from various angles. Because of the lower gain, flat screens are more effective
when ambient lighting is reduced.
Figure 2-1. Audience Coverage with Flat Screen
Figure 2-2. Audience Coverage with Curved Screen
Curved screens have gains larger than 1 (due in part to the screen material) and
viewing angles much less than 180°. Most curved screens have different
horizontal and vertical viewing angles. Incident light does not reflect equally in
all directions. The reflected light concentrates in a conical volume or "viewing
cone". Audiences within the viewing cone see a brighter image than that from an
equal area on a flat screen. Audiences outside the viewing cone see a dimmer
image.
NOTE: VistaGRAPHX 2500 lenses are designed primarily for use with flat
screens. However, its depth-of-field range allows the lens to be focused on
curved screens as well. Focus remains sharp in the corners, however there may
be significant pincushion distortion, primarily at the top of the screen.