Hd In Function Of The Lens Throw Ratio (Tr) - Barco F70 Series User Manual

RESTRICTED
AREA
Image 1-3
RA Restricted Access location (Enclosed projection
area)
PR Projector.
TH Theater (observation area).
Restriction zone (RZ) based on the HD continued.
For this type of setup 3 different HD shall be considered:
• HD as discussed in "High Brightness precautions: Hazard Distance (HD)", page 6 , relevant for intrabeam
exposure.
• HDreflection : the distance that has to be kept restrictive related to the reflected light from the rear
projection screen.
• HDdiffuse : the relevant distance to be considered while observing the defuse surface of the rear projection
screen.
As described in "High Brightness precautions: Hazard Distance (HD)", page 6 , it is mandatory to create a
restricted zone within the beam areas closer than any NOHD. In the enclosed projection area the combination
of two restricted zones are relevant: The restricted zone of the projected beam toward the screen; taking into
account 1 meter Separation Width (SW) from the beam onward. Combined with the restricted zone related to
the rear reflection from the screen (HDreflection); also taking into account a 1 meter lateral separation.
The HDreflection distance equals 25% of the difference between the determined HD distance and the
projection distance to the rear projection screen. To determine the HD distance for the used lens and projector
model see graphs in chapter "HD in function of the lens Throw Ratio (TR)", page 8 .
HDreflection = 25% (HD – PD)
The light emitted from the screen within the observation shall never exceed the RG2 exposure limit,
determined at 10 cm. The HDdiffuse can be neglected if the measured light at the screen surface is below
5000 cd/m² or 15000 LUX.

1.6 HD in function of the lens Throw Ratio (TR)

TR (Throw Ratio)
The ratio of the distance to the screen (throw) to the screen width.
RA
RZ
PR
TH
HD
DIFFUSE
PD
HD
REFLECTION
RZ Restriction Zone
PD Projection Distan
SWSeparation Width. Must be minimum 1 meter.
601–426-03
Safety
F70 Series 17