Barco DP2K SLP Series, Service Manual

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R5906848 /04 DP2K SLP Series 171
15.2.2 Measuring the light output
Introduction
Typically the screen luminance is measured in the screen center, from a location in the auditorium closest to
the geometric center of the screen. However with high gain screens, the center measurement may not
produce the highest luminance value.
Gain screens have a ‘ hotspot ’ , i.e. a location on the screen where the luminance is the highest.
The location of the hotspot on the screen however is not fixed. It depends on the relative position of the viewer
and projector, projector tilt, screen tilt and curvature etc.
All calculations we use predict the brightness in the hotspot of the screen (and not the screen center), so it is
important to measure in the screen hotspot, rather in the screen center.
Required tools
• Tripod
• Light meter
• Communicator software
Full power white luminance in 2D mode
1. Make sure that the necessary color calibration has been done for the projector (white point color calibration as
well as regular color calibration). For more information about the correct procedure, consult the Communicator
manual, chapter
“ Color calibration for Laser Phosphor based projectors ” .
2. In Communicator software, switch on the light source (go yo Controls and switch on lasers)
3. Browse to Installation ➙ Illumination and click on Light output .
• Set light output to Normal Mode
• Set dimming value to 100%
4. Put the projector in 2D mode (in Communicator, select Configuration ➙ 3D ➙ Activate 3D file and select
No3D ).
5. Switch on the uncorrected white test pattern (RGB-12bit-FullScreenWhite – uncorrected) and let the projector
warm up for at least 5 minutes (in Communicator, select Control ➙ Test Patterns ➙ Change pattern and select
the correct pattern).
6. During this time, look for a reference measurement position in the center of the auditorium (typically in the half,
or upper half of the seating area). Place the light meter mounted on a tripod on that position. Write down that
position for later measurements.
7. Visually look for the hotspot on the screen and point the light meter towards that spot by moving along the
vertical line. While moving the light meter, execute consecutive measurements to find the position with the
maximum luminance reading.
8. Fix the light meter to that position. This will be the reference position for all measurements.
9. Making sure that he light source is still at maximum and that uncorrected white pattern is selected.
Measure the foot-Lamberts (fL) on screen to obtain the Full Power Native White Luminance value. Enter it
directly in the SmartCare user interface.
10. Select the corrected white testpattern (RGB-12bit-FullScreenWhite) (in Communicator, select Control ➙ Test
Patterns ➙ Change pattern and select the correct pattern).
11. Without changing the light meter position, measure the foot-Lamberts (fL) on screen to obtain the Full Power
Calibrated White value. Enter this value in the SmartCare user interface.
Target luminance 2D scope
1. While running a corrected white test pattern, measure the light output while reducing the dimming to obtain
Target lumuninance 2D scope . Enter the dimming value in the SmartCare user interface.
Color calibration & Light measurements