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R5905754 /13
DPxK-32B
67
5.6 Back Focal Length adjustment
When to adjust the Back Focal Length?
If a lens is used with a throw ratio suited for the application, (lens selection depends on projection distance
and screen size) typically one would NEVER need to adjust the Back Focal Length of the projector.
A Back Focal Length adjustment is only required in case the Focus range of the installed lens does not
capture the projection screen either for FLAT and/or for SCOPE. In other words, when it is impossible to focus
the image on the screen for FLAT and/or for SCOPE. Note that the lenses for the DPxK-32B series projector
are varifocal. So, switching between FLAT and SCOPE (zoom action) requires a readjustment of the focus.
What is Back Focal Length adjustment?
Back Focal Length adjustment means moving the lens plane (Lp), thus the Lens Holder front plate, closer to or
further from the DMD plane. The closer the lens plane to the DMD plane the further the focus range (Fr) of the
lens will be.
S
C
R
E
E
N
DMD
Lp1
Lp2
Fr1
Fr2
Image 5-13
Do not abuse the Back Focal Length adjustment of the Lens Holder. Neglecting this will result in
loss of image quality because of the lens design. Cases requiring Back Focal Length adjustment
normally indicate incorrect lens choice (throw ratio).
Required tools
•
Nut driver 10mm.
•
Allen wrench 3mm.
•
Nut driver 13mm.
How to check the Back Focal Length
1.
Ensure that the throw ratio of the installed lens matches with the requirements of the application (projection
distance and screen size).
2.
Ensure that the correct lens parameters are activated. (See user guide of the
“
Communicator
”
chapter
Installation
>
Advanced
>
Lens parameters
)
Caution:
Not using the correct lens parameters could result in lens damage.
3.
Perform a lens
HOME & RETURN
operation. (See user guide of the
“
Communicator
”
chapter
Installation
>
Advanced
>
Lens parameters
)
4.
Project the green focus test pattern. (screen file
“
no masking
”
or
“
no
“
crop
”
)
Summary of Contents for DP K-32B Series
Page 1: ...ENABLING BRIGHT OUTCOMES User and Installation manual For DP2K 32B and DP4K 32B DPxK 32B ...
Page 8: ...R5905754 13 DPxK 32B 8 ...
Page 58: ...R5905754 13 DPxK 32B 58 Lamp Lamp House ...
Page 76: ...R5905754 13 DPxK 32B 76 Lenses lens holder ...
Page 94: ...R5905754 13 DPxK 32B 94 Input communication ...
Page 96: ...R5905754 13 DPxK 32B 96 Installing a HDD into the ICMP ICMP ...
Page 128: ...R5905754 13 DPxK 32B 128 Communicator Touch Panel ...
Page 154: ...R5905754 13 DPxK 32B 154 Maintenance ...
Page 162: ...R5905754 13 DPxK 32B 162 Convergence ...
Page 170: ...R5905754 13 DPxK 32B 170 Specifications ...
Page 188: ...Index R5905754 13 DPxK 32B 188 USB 3 0 101 User definition 10 Z Zoom 65 ...
Page 189: ...R5905754 13 DPxK 32B 189 ...
Page 190: ...Barco NV President Kennedypark 35 8500 Kortrijk Belgium www barco com R5905754 13 2018 11 12 ...