Color coordinates

ASTM D2244, Methodfor Calculation of Color Differencesfrom Instrumentally Measured Color Coordinates, Vol. 6.01, ASTM, Philadelphia, Pa., 1989. 

There has been a tremendous change in the last two decades as computers have taken over the tedious calculations involved in color measurement. Indeed, microprocessors either are built into or are connected to all modem instmments, so that the operator may merely need to specify, for example, x,j, Y or T, i , b or T, (A, b, either for the 2° or the 10° observer, and for a specific standard illiiminant, to obtain the desired color coordinates or color differences, all of which can be stored for later reference or computation. The use of high intensity filtered Xenon flash lamps and array detectors combined with computers has resulted in almost instantaneous measurement in many instances. 

Consumers expectations depend on several factors including cultural background, past experiences, desire for color coordination, esthetic appeal, local customs, fads, etc. Thus, eg, a Texas red hot sold ia the South is often colored quite differently than one sold ia the North, Midwesterners prefer butter with a deep yellow color, and on birthdays the decoration on a boy s cake are often blue and those on a gid s are often pink. 

Ali2arin is a mordant dye forming various colored coordination complexes with different metallic salts (11,12). Based on analytical results, a stmctural formula has been proposed for the ali2artn complex (13). 

The C1E color coordinates are obtained by a similar procedure, repeating the convolution for each of the tabulated color matching functions that describe the response of the ideal observer s blue, green, and red cones (b, rA). 

Given the color coordinates of x= 0.34 y = 0.51. Identify the color having this property. If x = 0.34 y = 0.61, identify the difference between these two colors. Identify the amounts of red, green and blue in each of these. 

No significant variation in the color coordinates measured at different spots of the investigated PHA coatings was observed (Table 5). This demonstrated clearly that all coatings were uniform in color and that the different pigments... 

Get an NMR tube. They are about 180 mm long, 5 mm wide, and about a buck apiece for what is euphemistically called the inexpensive model. The tubes are not precision ground, and some may stick in the NMR probe. This should not be your worry, though. They also have matching, color coordinated designer caps (Fig. 134). 

Active area Pitch size Color coordinates Voltage Panel current Pixel current Luminance Luminous efficiency Power efficiency Power consumption... 

In realizing the poor film-forming property of 9,10-(diphenyl)anthracene, the Kodak group improved this property by designing a series of blue emitters based on further substituted anthracene derivatives. The chemical structures of these materials were patented in a U.S. Patent in 1999 [239], In their patent, Kodak also reported the EL data using one of these compounds as a host material and using TBP as a blue dopant (Scheme 3.62). The device structures is ITO/CuPc/NPD/anthracene compounds.5%TBP/Alq3/Mg Ag. The EL of the device showed blue emission with CIE color coordinates of (0.144, 0.196). Without the... 

FIGURE 3.12 Normalized PL spectrum of Device 3 (open squares), EL spectrum of Device 1 at 10 V (solid circles), and the EL spectra of Device 2 biased at 8, 10, 12, and 14 V (solid and dashed lines) (left). Color coordinates of the EL vs. applied voltage. The EL of all of the devices blue-shifted with increasing voltage (right). (From Cheon, K.O. and Shinar, J., Appl. Phys., 81, 1738, 2002. With permission.)... 

If there is one clear need in the field of OLED materials it continues to be in the area of blue emitters. A blue emissive material with good color coordinates CIE (0.10, <0.10) coupled with long device lifetime (>10,000 h) and high electrical efficiency (>5 cd/A) is the holy grail of materials chemists in this field. A major effort to find such materials continues in many laboratories including our own and the current sets of available materials may be supplanted at any time. However, the current best candidate blue emitters in the SMOLED area compromise many desirable properties — the most troublesome being long lifetime. 

In Figure 9.13c, the EL spectra of the red-light-emitting a-Si H TFT AM-PLED and PLED are shown. EL peak positions at 654 and 653 nm, and full-width-at-half-maximum (FWHM) of 101 and 105 nm were obtained, for the a-Si H TFT AM-PLED and PLED, respectively. From the obtained EL spectra, Commission Internationale de l Eclairage (CIE) color coordinates [31] were calculated for AM-PLED and PLEDs, as shown in the inset of Figure 9.13c, and were found to be (0.67, 0.33) and (0.67, 0.32), respectively. These very... 

FIGURE 9.13 Optoelectronic characteristics of AM-PLED, (a) Calculated display luminance and estimated display luminance versus /data characteristics, (b) measured Paata evolution with the /data, and (c) PLED and AM-PLED electroluminescent (EL) spectra are shown. The CIE color coordinates of the PLED and AM-PLED are also shown in the inset of this figure. (From Hong, Y., Nahm, J.-Y., and Kanicki, J., IEEE J. Selected Top. Quantum Electron. Org. Light-Emitting Diodes, 10, 1, 2004 With permission.)... 

Colors specified in terms of the tristimulus values X, Y, and Z are fairly hard to visualize. For this and other reasons, a variety of different color systems have been devised. The color coordinates in these systems can be calculated from the X, Y, and Z values, which are of central importance to color measurement because of their close link to measurable quantities. 

In colorimetric terms, color differences are generally characterized by the distance between two colors in one of the color notation systems, most commonly the CIELAB system. The difference determined in this way represents the total color difference. Since a color is characterized by three quantities, a color difference can also be expressed in terms of three difference components (that is, differences in the color coordinates) and thus described in greater detail. Visually equal color differences between almost equal colors may, upon colorimetric measurement, be considered distinct if the colors of one pair differ strongly from those of the other pair. The formulas for color differences are further elaborated in order to remedy this defect. 

One of the main tasks for display applications is the combination of materials of different colors to produce white light and full-color devices. For that reason, separate strategies aim at the development of blue-, green-, and red-emitting materials with suitable color coordinates. 

Color is determined by reflectance and can be determined by using a colorimeter based on the CIE color system. This method expresses the brightness as Color L, the absorption at the green-red axis as Color a and the yellowness as Color b along the blue-yellow axis of this color coordination system. 

Figure 4. Lumen equivalent values of several spectral distributions having the color coordinates x = 0.65, y = 0.35 (1-5)...

MATERIAL RELATIVE BRIGHTNESS COLOR COORDINATES X Y Y RELATIVE ENERGY EFFICIENCY RELATIVE COLOR GAMUT COMMENT... 

The authors are honored by the invitation of Karl A, Gschneidner, Jr, to present this paper at the Second Chemical Congress of the North American Continent, They are also indebted to Joseph G, Cannon of Molycorp, Inc, and H, Holt Apgar of Rhone-Poulenc, Inc, for discussions relating to the market for rare earths. We acknowledge with thanks Wayne Person of GTE Sylvania, Towanda, PA, who provided the brightness and color coordinate data in Table I,... 

Coordination Number Color Coordination Number Color... 

Initial current, voltage, luminance, color coordinate properties, and luminance degradation properties were evaluated for the step 5 product and a styryl comparative. Testing results are provided in Table 1. 

Entry Curr. Eff cy (cd/A) Voltage Lum (cd/m2) Color Coordinate Properties (x) Color Coordinate Properties O ) Lum Half Life (h) Life Test Lum (cd/m2)... 

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