Barco DP2K-17BLP, User And Installation Manual

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7. Lenses & lens holder
for SCOPE. Note that the lenses for the DPxK BLP-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.
SCREEN
DMD
Lp1
Lp2 Fr1
Fr2
Image 7-20
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).
Necessary 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 fi le “no masking” or “no “crop”)
Image 7-21
5. Zoom the lens for maximum image on the screen ( WIDE ).
6. Is it possible to focus the center of the projected image?
If yes, the Back Focal Length is OK.
If no, the Back Focal Length needs realignment. Proceed with the next procedure.
How to adjust the Back Focal Length?
1. Unlock and loosen the 4 set screws (reference 11 image 7-22) of the Lens Holder by 1 centimeter. Use a 10mm nut driver for
the lock nuts (reference 21 image 7-22) and use a 3mm Allen wrench for the set screws.
R5906753 DPXK BLP SERIES 20/11/2017 71