Measuring Principle - Konica Minolta CA-310 Instruction Manual

Measuring Principle

1. Measuring Principle
This instrument uses sensors of a spectral sensitivity similar to the CIE 1931 color-matching function (x λ , y λ , z λ )
to measure RGB emission energy of a color display, and displays the results in xyLv, T ∆ uvLv, u'v'Lv or XYZ
values.
Measurement is performed in the following sequence.
A RGB emission energy of the color display is acquired through the measuring probe's receptor, and then
converted to a voltage by the photoelectric conversion section. (Outputs: X, Y, Z)
B The temperature of the probe is detected by the temperature detection section. (Output: T)
C The outputs (X, Y and Z of A ) from the photoelectric conversion section and the output (T of B ) from
the temperature detection section are digitized in the A/D conversion section. A/D conversion is per-
formed simultaneously within the measurement time according to SYNC mode.
D The digitized values (counts) are sent to the instrument's CPU, where they are calculated according to the
measurement mode, SYNC mode and correction factor (user calibration), which have been set via
the software.
E The processing results are then output to a PC via RS-232C or USB.
Chromaticity coordinates (x, y) for xyLv (CIE 1931 color space) are obtained by the following formula.
X
x =
X + Y + Z
Measuring probe
Photoelectric
conversion section
Photoelectric
conversion section
Photoelectric
conversion section
Temperature
detection section
Y
y =
X + Y + Z
1 .0
0 .9
0 .8
0 .7
0 .6
0 .5
0 .4
0 .3
0 .2
0 .1
0 .0
400 450 500 550
Wavelength (nm)
Fig. 1 Instrument's Spectral Sensitivity
Main body
A/D
conver-
sion
section
Fig. 2 Measurement Block Diagram
X, Y and Z in the formula are tristimulus values
600 650 700 750
Vertical
synchronizing
signal input
PC PC
VSYNC RS-232C
USB
port connector connector
USB
RS-232C
driver
driver
C P U
SRAM
Multi-point expansion
board connector
90
Instrument's spectral sensitivity
CIE 1931 color-matching function
FROM
PIO
Display
section
KEY