Display Standard - Veritas et Visus

Veritas et Visus Display Standard February 2009
Permeation-Rate Measurements System and Its Application to Polymeric Substrates
Jin Hwan Choi, Young Min Kim, Young Wook Park, and Byeong Kwon Ju, Korea University, Seoul, South Korea
In Sun Kim, and Hee Nam Hwang, i-components, Pyongtaek-City, South Korea
The researchers report on a measurement system including an analysis of an electrical mechanism based on calcium
degradation. Polymer substrates provide better flexibility compared to metal or glass and better ruggedness than
glass, but do not provide sufficient protection to water permeation. Therefore, a substrate barrier structure is
required in addition to a single inorganic top barrier. In this work, the researchers report on a measurement
principle including an analysis of an electrical mechanism based on calcium degradation. They can measure an
accurate gas permeation rate with a high
sensitivity and a structural compatibility. The
structural advantages of the devised test
sample enable applications to various kinds of
fabrication processes of passivation layers.
In this system, quantitative water vapor
transmission rates were measured in the range
of 10–10 -5 g/m 2 /day. It is particularly useful to
evaluate time-dependent barrier properties.
This method presents a direct comparison of
the gas permeability of plastic substrates that
are a part of the polymeric passivation layer
coating technologies. The test sample structure
and measurement principle results in an
application to evaluate the barrier performance
for stability of flexible electronics.
The schematic diagram of water permeation measurements system
Colorimetric Characterization of High-Dynamic-Range LCDs
Yu-Kuo Cheng, and Han-Ping D. Shieh; National Chiao Tung University, Hsinchu, Taiwan
A modified model, incorporating backlight intensity, for chromatic characterization of HDR LCDs is proposed.
Images, exemplifying regular and random backlight distributions, were designed to evaluate the proposed model.
The results showed that chromaticity of three primaries varied with incident backlight intensity. An HDR LCD
features a local-dimming backlight, while the backlight of a conventional LCD is full on over the entire panel. This
differentiation produces a critical issue if the color model of the conventional LCD is applied to the HDR LCD. To
answer the question, chromatic properties of the HDR LCD were first examined, and then a modified
characterization model was proposed. Finally, the proposed model was evaluated in comparison with the model
dedicated for the conventional LCD.
Backlight dimming not only extends the contrast ratio, but also increases the complexity of chromatic properties of
the HDR LCD. The measured data show that area-adaptive backlighting results in one-to-many chromatic mapping,
rather than a one-to-one mapping relation in the case of full-on backlighting. Therefore, a suitable chromatic model
is required to substitute device-dependent color transformation for colorimetric color reproduction in the HDR
LCD. The proposed model, taking account of backlight intensity, is demonstrated to be more applicable than the
conventional model for chromatic characterization of the HDR LCD.
Current results reveal that the improvement of reducing color difference is significant; however, the model
performance can be further enhanced if the estimation of backlight intensity can be improved. Applying a nonlinear
optimization technique is another solution to enhance color reproduction accuracy. In addition, this model
can be modulated accordingly to well characterize the HDR LCD with multi-primary LEDs as the backlight source.
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