In this presentation on Colorimetry we will look at how the eye perceives color, and discuss several metrics which describe color.

1. LED Fundamentals
Optical Basics
p
Colorimetry
07-07-2011

2. Light and the Eye
The eye has incredible
dynamic range
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3. Colorimetry
Colorimetry is the science that describes colors in terms of numbers.
Metamerism – different power spectra, same color coordinates
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4. Colorimetry
 Roughly speaking the retina of the human eye has photoreceptors for red green and
speaking, red, green,
blue.
 Spectral distribution coefficients have been defined which allow us to compute color
coo d a es
coordinates.
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5. Color Coordinates
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6. CIE Chromaticity Diagram
(u′, v′) chromaticity diagram, also
known as the CIE 1976
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7. Correlated Color Temperature (CCT)
• Temperature of a blackbody radiator
p y
closest in appearance.
• Attempt to use a single number to
characterize a full spectrum.
• Pl ki l
Plankian locus: colors of bl kb d
l f blackbody
radiators
• Judd lines: perpendicular to Plankian locus
in uv color space
• CCT: for colors on a Judd line, CCT is the
temperature of the blackbody radiator at
the intersection with the Plankian curve
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8. Color Rendering Index (CRI)
Fair
50-70 CRI
Better
70-80 CRI
Best
80-100 CRI
Source: Energy Star
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9. MacAdam Ellipse
Region in color space containing those
colors which are indistinguishable to the
average human eye from the color at the
center of the ellipse.
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10. Example of OSRAM’s Binning Scheme
0.45
3000K
3500K 9
3-step MacAdams ellipses
8
4000K 7 Planck
6
4500K
0.40 5
5000K
4
W X
5700K
T U V
S
R
6500K
Q ANSI C78.377
P
O q
quadrangles
g
N
0.35 M 2500K
L
K 3000K
J
8 I
7 H 4000K
6 G
F
5
E
4 D
C
0.30
0.28
0.33
0.38
0.43
0.48
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11. Disclaimer
All information contained in this document has been checked with the greatest care.
OSRAM Opto Semiconductors GmbH can however, not be made liable for any damage
that occurs in connection with the use of these contents.
OSRAM Opto Semiconductor GmbH makes no representations and warranties as to a
possible interference with third parties' intellectual property rights in view of products
originating from one of OSRAM Opto Semiconductor GmbH's partners, or in view of
products being a combination of an OSRAM Opto Semiconductor GmbH's product and a
GmbH s
product of one of OSRAM Opto Semiconductor GmbH's partners. Furthermore, OSRAM
Opto Semiconductors GmbH cannot be made liable for any damage that occurs in
connection with the use of a product of one of OSRAM Opto Semiconductor GmbH's
partners, or with the use of a combination of an OSRAM Opto Semiconductor GmbH's
product and a product of one of OSRAM Opto Semiconductor GmbH's partners.
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12. Disclaimer
This document constitutes neither an offer to sell nor a solicitation to buy or subscribe
for
f securities. Any such offer will b made solely on th b i of th S
iti A h ff ill be d l l the basis f the Securities
iti
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(BaFin) and published thereafter. The information legally required to be provided to
investors will be contained only in the Securities Prospectus
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The information contained herein is not for distribution, directly or indirectly, in or
into the United States of America (including its territories and possessions of any
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distributed to U.S. persons (as defined in Regulation S under the U.S. Securities Act
of 1933, as amended ("Securities Act")) or publications with a general circulation in
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This document is not an offer of securities for sale in the United Kingdom, Canada,
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Australia.
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13. Thank you for your attention.
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