• Journal of Korea Multimedia Society
• /
• v.12 no.7
• /
• pp.1016-1021
• /
• 2009

Among many factors for evaluating the performance of color printers, the color uniformity is an important factor during the stage of development and mass production. Currently the color uniformity is measured manually using densitometers and the data is analyzed by inspectors to evaluate the performance. In this paper a new method of estimating the color uniformity using scanners and average brightness is presented. The color uniformity of printouts is estimated by using the test pattern and commercially available scanner. It is shown from experiments that the estimated data are similar to the data measured by densitometers. Also, with the analysis of the color uniformity, the usefulness of the proposed approach is presented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.27 no.4
• /
• pp.1-7
• /
• 2013

Optical characteristics including the view angle and color temperature uniformity of LED packages with an integrated lens fabricated by compression molding method are investigated according to lens shape, lens materials, and phosphor coating methods. Four types of lens shape are designed and their optical output power dependence on the refractive index of silicone encapsulant are evaluated. Also, spatial color temperature uniformities of packages fabricated with different phosphor coating methods-direct coating on a chip vs. uniformly mixed with silicone encapsulant- are compared at various view angles. As the result, it is found that phosphor coating method is more effective on color temperature uniformity than lens shape. The maximum color temperature difference of a package with direct coating of phosphor on a chip is 1,340K according to the view angle at the color temperature of 5,000K, and that of a package with uniformly mixed phosphor is 250K, which indicates 1,090K improvement of color uniformity for the latter case.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2009.10a
• /
• pp.850-853
• /
• 2009

Many well-known pixel compensation circuits have been applied to control TFT $V_{th}$ variations on small size AMOLED panels. For large (>30-inch) AMOLEDs, luminance and color uniformity are affected by TFT variations, but also by ELVDD IR drop and cavity non-uniformity which are not easily compensated by in-pixel circuits. AMOLED panels may also suffer from manufacturing-induced mura. An external compensation method based on optical measurements is proposed and applied to large AMOLED panels. It improves luminance uniformity by up to 95% at 200nits and color uniformity by up to 99% (${\Delta}$u'v' <0.004) on large AMOLED panels, and provides-increased margin against processinduced mura.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.23 no.1
• /
• pp.38-41
• /
• 2010

Compared to conventional molding technology, the color uniformity of light direction emitted from LED is improved with PCB type lead frame technology in which metal thin film is used and transfer molding technology which makes the density of phosphor uniform by manufacturing high density LED lamp. The light efficiency and the color uniformity of the LED are improved by molding the phosphor layer outside of chip and controlling the thickness of the phosphor layer. CIE x,y difference of LED in major axis is also improved uniformly from 0 to 90 degrees.

• Journal of the Ergonomics Society of Korea
• /
• v.26 no.4
• /
• pp.33-39
• /
• 2007

In the full white pattern, white uniformity means the degree of uniform distribution of white color and luminance across the whole screen. Among the FPDs(Flat Panel Displays), the TFT-LCD has weak point of viewing angle. The viewing angle considering location and direction can cause different image quality of the TFT-LCD. Therefore, white uniformity of the TFT-LCD must consider viewing angle. Based on international standards, this study proposes an alternative that is realistic and ergonomic measurement of white uniformity of the TFT-LCD.

• Journal of Broadcast Engineering
• /
• v.22 no.2
• /
• pp.207-213
• /
• 2017

In order to accurately perform multispectral imaging using a multiplexed illumination, intensity of illumination in a scene must be uniform. For image acquisition that requires accurate color information, even if not multispectral imaging, the illumination information must be accurate, and a flat light source or illumination calibration is performed for accurate illumination characteristics. In this paper, we propose a method of color correction to uniformly illuminate an image with non-uniform illumination intensity. The proposed method uses multispectral imaging instead of illumination calibration for color correction. First of all, we perform multispectral imaging with two images obtained from non-uniformity illumination to acquire spectral reflectance. The obtained reflection spectrum is relit as the illumination characteristic of the image obtained from general planar light such as fluorescent light or sunlight. By comparing the image obtained by relighting with the uniformly illuminated image, the non-uniformity of the illumination is confirmed, and the color correction is performed as the image obtained from the uniform image. It is expected that the experimental results will confirm whether the non-uniformity of the illumination is uniformly corrected and reduce the restriction of illumination in obtaining the color information of the image.

• Journal of the Optical Society of Korea
• /
• v.17 no.6
• /
• pp.506-512
• /
• 2013

Recently, the color separation issue of wide-spreading white LEDs has attracted attention due to their wide applicability as light sources in direct-lit LCD backlights. These wide-spreading LED packages usually consist of LED chips, a color-conversion phosphor layer, and a light-shaping lens. The technical aspect of this color issue was related to a method for balancing the yellow spectral component emitting from phosphors with respect to the blue one from the LED chip as a function of viewing angle. In this study, we suggested an approach for carrying out quantitative analysis for the color separation problem occurring in wide-spreading LED packages by optical simulation. In addition, the effect of an internal scattering layer on the color uniformity was investigated, which may be considered as a potential solution for this problem.

• Fashion & Textile Research Journal
• /
• v.1 no.3
• /
• pp.275-279
• /
• 1999

The purpose of this study was to investigate a specific character on products of Korean cotton and American cotton with cultivated in sangju city, Korea. The results of this study were as follows: Productivity of American cotton was nine times higher than those of Korean cotton. Spinning coefficient index (SCI: 140), strength (32.6 g/tex), fiber length (1.12 inch), uniformity index (83.4%), short fiber index (6.4), color grade (21) of American cotton was superior than SCI (122), strength (27.7 g/tex), fiber length (1.02 inch), uniformity index(81.1 %), short fiber index (10.6), color grade (23) of Korean cotton. Microaire (3.5), elongation (6.9%) of Korean cotton was superior than American cotton.

• Textile Coloration and Finishing
• /
• v.31 no.1
• /
• pp.25-32
• /
• 2019

The influence of the contact amount of carbon dioxide per unit mass of dyestuff(${\alpha}$) on dyeing uniformity in supercritical fluid dyeing is analyzed in this study. The experiments using a 5L class Pilot Scale dyeing machine is carried out for this study purpose. For a fixed temperature and pressure, the amount of sample and the dyeing leveling time were considered as process variables. The results show that the increase in the amount of the sample causes a higher color difference than the reference sample, and it also increases the amount of residual dye. On the other hand, the color difference tended to decrease with the increase in dyeing time. Based on these results, the correlation between ${\alpha}$ value and dyeing uniformity in supercritical fluid dyeing is obtained.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.24 no.12
• /
• pp.38-46
• /
• 2010

For the development of 100[W] stage lighting, quantitative and uniform color mixing that applied through color adopted Simple-Inverse matching so that color mixing can be possible along Black Body Locus. R,G,B(Red, Green, Blue) LED(Light Emitting Diode) arrangement through LED package character analysis, LED module, and the characteristic of device were considered for uniform color mixing. A distance changeable optical device was built to assure high uniformity and high diffusion of not only the middle of diffusion side but also the border side. Also, we developed the control power circuit that can expand up to 6 channels which are possible for quantitative color mixing, and the high uniformity and high quantified border light for color mixing control and the verification of color mixing characteristics by composing GUI(Graphical user interface) including color mixing simulator. By presenting the experimental results of light color control, we proved the usefulness of our developed border light and the proposed color mixing method.