• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.380-383
• /
• 2007

In this research, we present color filter which is patterned by screen printing method. Analysis of screen printing process, screen printing system, experiment for uniform printing in large area, characteristics of screen printed CF are investigated .In spite of limitation of precision, screen printed color filter is very cost- effective in respect of manufacturing facility and ink usage.

• Current Optics and Photonics
• /
• v.7 no.5
• /
• pp.485-495
• /
• 2023

The pixel size in high-resolution complementary metal-oxide-semiconductor (CMOS) image sensors continues to shrink due to chip size limitations. However, the pixel pitch's miniaturization causes deterioration of optical performance. As one solution, a quad color filter (CF) array with pixel binning has been developed to enhance sensitivity. For high sensitivity, the microlens structure also needs to be optimized as the CF arrays change. In this paper, the covered microlens, which consist of four microlenses covered by one large microlens, are proposed for the quad CF array in the backside illumination pixel structure. To evaluate the optical performance, the suggested microlens structure was simulated from 0.5 ㎛ to 1.0 ㎛ pixels at the center and edge of the sensors. Moreover, all pixel structures were compared with and without in-pixel deep trench isolation (DTI), which works to distribute incident light uniformly into each photodiode. The suggested structure was evaluated with an optical simulation using the finite-difference time-domain method for numerical analysis of the optical characteristics. Compared to the conventional microlens, the suggested microlens show 29.1% and 33.9% maximum enhancement of sensitivity at the center and edge of the sensor, respectively. Therefore, the covered microlens demonstrated the highly sensitive image sensor with a quad CF array.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2008.08a
• /
• pp.276-276
• /
• 2008

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.36 no.5
• /
• pp.494-499
• /
• 2023

In this paper, in order to apply the CF (color filter) type of the micro light emitting device (Micro LED) display method, a study on the manufacturing process of red and green phosphor inks for the inkjet process was conducted. The blue light-emitting KSF and LuAG phosphors were respectively used to control the phosphor particle size to about 1㎛, and a phosphor ink was prepared by synthesizing with a low-viscosity solution (IPA/Eg). A chemical dispersion method was applied to selectively control the dispersion characteristics in the manufacture of phosphor inks, and in particular, phosphor inks with a dispersant applied a dispersant secured stable dispersion characteristic compared to phosphor inks without a dispersion process. Therefore, it seems possible to manufacture CF for Micro LED through an inkjet process capable of controlling the dispersion characteristics of phosphor ink.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.04a
• /
• pp.165-168
• /
• 2003

최근 TV 대응 LCD 제품의 본격적인 양산과 더불어 LCD TV 의 색재현성에 대한 해결과제가 큰 문제로 대두되고 있으며, CRT 급 색재현성의 확보는 LCD TV 의 고급화를 위한 또 하나의 개발 방향이 되고 있다. 그러나, CF(Color Filter)만을 이용한 색재현성의 개선은 근본적으로 한계를 가지고 있으며, 패널 투과율의 저하로 이어져 또다시 고휘도 사양의 BL(Back Light)에 대한 요구가 발생하고 있다. 따라서 본 연구에서는 CF(Color Filter)만에 의한 색재현성의 개선이 아닌 BL 광원 자체의 스펙트럼 최적화를 통해서 CRT 급 색재현성의 확보를 통한 고부가가치 상품개발의 가능성을 제시하고자 하였다. 구체적으로, 램프형광체의 RED 와 Green-Blue 영역에서의 Intensity 향상을 통해서 기존의 CCFL(Cold Cathode Fluorescent Lamp)과는 다른 특성을 광원에 부가하여, 기본의 LCD 패널을 그대로 이용한 경우에도 색재현성을 약 11% 개선하였다.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2007.08a
• /
• pp.882-885
• /
• 2007

This study discussed the effect of ink adhesion on color filter glass after different kinds of plasma treatment. From contact angle analysis, we could get different ink adhesion results after HMDSZ, $O_2$, IPA, and $CF_4$ plasma treatment. Substrates after PFMCH plasma treatment have good surface hydrophobic property, and contact angle raise from $<10^{\circ}\;to\;50^{\circ}$.

• Applied Chemistry for Engineering
• /
• v.32 no.2
• /
• pp.214-218
• /
• 2021

We investigated the optimal stacked structure from the perspective of process architecture (PA) through emission spectrum analysis according to the wavelength of quantum dot (QD)-organic light-emitting diodes (OLED). We confirmed that the blue-light leakage through the QD can be minimized by increasing the QD filling density above a critical value in the red QD (R-QD) layer. In addition, when the thickness of red-color filter (R-CF) at the upper part of the R-QD increased to more than 3 ㎛, the leakage of blue light through the R-CF was effectively blocked, and a very sharp emission spectrum in the red wavelength band could be obtained. According to these outstanding results, we expect that the development of QD-OLED displays with very excellent color gamut can be possibly realized.

• Transactions on Electrical and Electronic Materials
• /
• v.8 no.5
• /
• pp.215-217
• /
• 2007

Recently, color reproduction properties have attracted lots of attention with mass production of LCD especially corresponding to TV application and achievement of color reproduction properties such as CRT have been considered one of technical goals for high quality display. However, revision of the color reproduction properties only with CF(color filter) have fundamental limitations and resultant decrease in the transmittance of panel causes demand on high brightness of BL(Back Light). In this paper, we present such a method in which by optimization of original light spectrum from the BL source will improves the color reproduction properties corresponding to them of the CRT. When the intensity of RED and Green-Blue from ramp is revised densely, the characteristics different from CCFL(Cold Cathode Fluorescent Lamp) used before become added so that about 11 % of the color reproduction properties is improved compare to the existing LCD panel.

• Current Optics and Photonics
• /
• v.4 no.5
• /
• pp.428-433
• /
• 2020

Recently, the on-chip autofocus (AF) function has become essential to the CMOS image sensor. An auto-focus usually operates using phase detection of the photocurrent difference from a pair of AF pixels that have focused or defocused. However, the phase-detection method requires a pair of AF pixels for comparison of readout. Therefore, the pixel variation may reduce AF performance. In this paper, we propose a color-selective AF pixel with a plasmonic nanostructure in a 0.9 μ㎡ pixel. The suggested AF pixel requires one pixel for AF function. The plasmonic nanostructure uses metal-insulator-metal (MIM) stack arrays instead of a color filter (CF). The color filters are formed at the subwavelength, and they transmit the specific wavelength of light according to the stack period and incident angles. For the optical analysis of the pixel, a finite-difference time-domain (FDTD) simulation was conducted. The analysis showed that the MIM stack arrays in the pixels perform as an AF pixel. As the primary metric of AF performance, the resulting AF contrasts are 1.8 for the red pixels, 1.6 for green, and 1.5 blue. Based on the simulation results, we confirmed the autofocusing performance of the MIM stack arrays.

• Journal of the Korean earth science society
• /
• v.36 no.7
• /
• pp.661-673
• /
• 2015

UBVI CCD photometry of the intermediate age open cluster NGC 7790 has been obtained using AZT-22 1.5 m telescope (f/7.74) at the Maidanak Astronomical Observatory in Uzbekistan. NGC 7790 contains three ${\delta}$ Cep variable stars including CEa Cas, CEb Cas, and CF Cas. PSF photometry was carried out using IRAF/DAOPHOT for all observations. The total number of stars observed both in V and I filter was 1008 and the limiting magnitude was $V{\approx}22$. To determine atmospheric extinction coefficients and photometric zero points, many blue and red standard stars as well as the standard stars in the celestial equator under various airmass were observed. Photometric data were transformed into the standard Johnson-Cousins' UBVI standard system. From the analysis of UBVI color-magnitude diagram and color-color diagram, the color excess in V and I filter [$E(B-V)=0.58{\pm}0.02$], the selective extinction ratio in V and I filter [$R_V{\equiv}A_V/E(B-V)=3.02{\pm}0.09$] and distance modulus ($V_0-M_V=12.65{\pm}0.10$) of the cluster were determined. The age of the cluster was estimated to be log $age=8.05{\pm}0.05$ [yr] based on the position of these three Cepheid variables in the color-magnitude diagram, the isochrone of the Geneva group ($Ekstr{\ddot{o}}m$ et al., 2012-Z=0.019), and the isochrone of the Padova group (Bressan et al., 2012-Z=0.014) were used to compare each other. Of them, the Geneva models that considered stellar rotation well described the position of ${\delta}$ Cepheid variables in the blue loop. Although they were well consistent with standard period-luminosity relation of ${\delta}$ Cepheid variables, three Cepheid variables in NGC 7790 were, on average, brighter by about 0.5 mag than the absolute magnitude estimated from the mean period-luminosity relation at a given period.