User Manual

Summary Color Brightness Test Data
April 2013 Page 17
METHODOLOGY
Experiment Design
The US National Institute of Standards and Technology in NISTIR 6657 (January 2009) provides detailed
guidance on the measurement of Color Light Output. The same guidelines are part of the ICDM-DMS 1.03a
Section 15.4 (International Committee on Display Metrology - Display Measurement Standard.) Both of these
documents were carefully followed in the design and implementation of the experiment and the apparatus
used.
Light Measurement Devices, Calibration and their Experimental Control
Lumita:
Two types of measurement instruments were used by Lumita for this study. Primary data for the 9 standard
measurement test points was gathered by a Photo Research PR-524 Illuminance meter with 9 PR-514 remote
heads. A NIST traceable calibration was performed at the factory on these heads prior to this experiment
and a current certificate of calibration is available.
Spectral measurements used as a control in every experiment and to correct the PR-514 data were made
with a Photo Research PR-670 Spectroradiometer and a CR-670 Illuminance head. The PR-670/CR-670
combination also holds a current NIST traceable certificate of calibration for both illuminance and spectral
accuracy.
Filter based photopic illuminance meters like the PR-524 are calibrated using Illuminant A (Tungsten.) Due to
the mercury lamps and dichroic filters used in DLP front projection displays the absolute accuracy of filter
based photometry that is calibrated with a wide spectrum source such as illuminant A could be questioned. In
fact our own experiences at Lumita demonstrate wide variability (when measuring projectors) among different
brands and models of photometers depending on the quality of their filter set.
In order to remove any error that might result from the unique spectra of the projector, a baseline spectral
correction factor was calculated for each projector model. With the projector stabilized, measurements were
taken of white at test point 5 (center.) The measurement jig allows the CR-670 head to be accurately (+-
0.5mm ) swapped with the PR-514 head. 8 alternating measurements were made and a spectral correction
factor for the PR-514 was calculated for each projector type.
As a further control to assure accurate operation of all systems the PR-670 was placed in the center position
at the beginning of data collection. For each trial a control spectral illuminance measurement was taken, then
the PR-514 head was returned and the trial completed. At the end of each trial the control was checked and
compared to the average test point 5 PR-514 data to make sure it was within the expected variability.
Intertek:
Below is a partial list of the test equipment used at Intertek to measure Color Brightness:
Description
Manufacturer
Model
Digital Power Meter
Yokogawa
WT230
Hydra II Data Acquisition Unit
Fluke
2625A
Programmable Power Source: 0-300 V/DC,15-1kHz / 2KVA
Chroma
1604
Hygro-Thermometer Datalogger
Extech
Easy View 25
Chroma Meter Model CL-200A
Konica Minolta
CL-200A