Hd In Function Of The Lens Throw Ratio (Tr) - Barco F80 Series User Manual

Safety
For this type of setup 3 different HD shall be considered:
•
HD as discussed in "High Brightness precautions: Hazard Distance (HD)", page 17, relevant for intrabeam
exposure.
•
HD : the distance that has to be kept restrictive related to the reflected light from the rear projection
reflection
screen.
•
HD : the relevant distance to be considered while observing the diffuse surface of the rear projection
diffuse
screen.
As described in "High Brightness precautions: Hazard Distance (HD)", page 17, it is mandatory to create a
restricted zone within the beam areas closer than any HD. 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 (HD
The HD distance equals 25% of the difference between the determined HD distance and the projection
reflection
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 20.
HD = 25% (HD – PD)
reflection
The light emitted from the screen within the observation shall never exceed the RG2 exposure limit,
determined at 10 cm. The HD
cd/m² or 15000 LUX.

1.4.4 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.
HD versus Throw Ratio
5
4.5
4
3.5
3
2.5
2
1.5
1
0.5
0
0.4 0.8 1.2 1.6
Image 1-4
Graph shows Hazard Distance in meters versus Throw ratio of the lens
20 R5906852-01 F80 series
); also taking into account a 1 meter lateral separation.
reflection
can be neglected if the measured light at the screen surface is below 5000
diffuse
F80-Q7, F80-4K7
2.0 2.3 2.7 3.1 3.5 3.9 4.3
F80-Ultra, F80-Q9, F80-4K9
4.7 5.1 5.5 5.9 6.3 6.7 7.1
Throw Ra o
7.5 7.9 8.3 8.7 9.1 9.5 9.9