• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.891-894
• /
• 2002

We studied characteristics of polyimide (PI) about Liquid Crystal on Silicon (LCOS) microdisplay. In order to compare two kinds of PI and choose one PI, we measured some items. First, we measured thermal imidization of SE-7492, SE-5291 (Nissan) PI using FT-IR. The results of thermal imidization are same 85%for SE-7492 and 86% for SE-5291. The second, we measured voltage-holding ratio (VHR) of LCOS imager using two kinds PI and one liquid crystal (LC) that is a mixture developed by Merck. The third, we measured contrast ratio (C/R) of LCOS imager using function generator from ov to 4V. The results of VHR and C/R are higher LCOS imager using SE-7492 than LCOS imager using SE-5291. And last we measured response time and the result is same two types LCOS Imagers. So, we choose PI of LCOS imager and concluded that LC is much better matched of PI using SE-7492.

• Journal of the Semiconductor & Display Technology
• /
• v.9 no.2
• /
• pp.87-90
• /
• 2010

A new SRAM pixel circuit with RESET Transistor of a LCOS display module was designed for a pico-projector application. A dual-block PWM method was also proposed to realize the field sequential color system having only one LCOS panel. 0.29 inch LCOS panel in SVGA resolution was fabricated and the proposed dual-block PWM method was tested with it. Discontinuity of brightness curve was caused due to multi-pulses and it was improved by the adoption of proper mapping table. With the proposed SRAM with RESET pixel circuit and dual-block PWM method, the test images were successfully demonstrated.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2022.10a
• /
• pp.469-471
• /
• 2022

This paper presents an implementation of a calibration circuit to correct the gain error, DC offset and sampling clock phase error generated in the process of converting digital pixels to analog pixels to drive an analog-driven 4K UHD LCOS panel. The proposed calibration circuit consists of a gain and DC offset adjustment circuit and a sampling clock phase adjustment circuit. The calibration circuit is implemented with an FPGA device, and video amplifiers.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.6
• /
• pp.744-749
• /
• 2016

This paper presents the design of a computer-generated hologram for beam control of an LCOS-based wavelength selective switch, which is the core technology for next-generation ROADM. By introducing a computer-generated hologram instead of general grating patterns to control the LCOS device, we contribute to building a more efficient wavelength selective switch. With the use of phase modulation properties of LCOS devices, we designed the hologram for five-port output and a 40-channel wavelength selective switch. We applied a multi-level phase modulation technique with the Gerchberg-Saxton algorithm to produce the hologram, which is easily scalable to any different type of wavelength selective switch. With an experimental setup, we verified the usability of the hologram designed for five-port output. We also suggest a hologram design technique for beam control of a 40-channel wavelength selective switch.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.8
• /
• pp.5288-5293
• /
• 2014

This paper presents the characterization of the wavelength selective switch using a LCOS display instead of a MEMS device, which is a core technology for the next generation ROADM. We constructed a five-port WSS, and examined the basic characteristics of the WSS, such as the response time, beam steering, insertion loss, and channel isolation. The response time of WSS was 11.6 mS and the beam steering characteristics of LCOS was well performed. The measured insertion loss at 40 channels in the c-band were 5.5~12.7 dB and channel isolation was 16~18 dB. Although the characteristics of LCOS-based WSS are inferior to the conventional MEMS-based WSS, it can be improved by additional experiments that secure the technology competitiveness.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.46 no.8
• /
• pp.6-11
• /
• 2009

The electro-optical characteristics of the Liquid Crystal on Silicon (hereinafter "LCOS") micro-display on vertically alignment (VA) mode were studied with 3-dimensional LC code. 5 different cell gaps, such as 1.4 ${\mu}m$, 1.8 ${\mu}m$, 2.1 ${\mu}m$, 2.4 ${\mu}m$ and 2.8 ${\mu}m$, were selected. The reflectance-voltage (R-V) characteristics, distribution of reflected light, reflectance, optical fill factor and contrast ratio were calculated and investigated depending on various cell gaps. Due to the surface anchoring effect, higher cell gap showed higher reflectance. However, considering the optical fill factor and contrast ratio, middle-height 2.1 ${\mu}m$ showed the best electro-optical characteristic. 0.7 inch Full-HD LCOS panels having same geometry and material property were fabricated. The reflected light intensity and contrast ratio were measured and the measured results were well-matched to the calculated results.

• Nuclear Engineering and Technology
• /
• v.37 no.1
• /
• pp.109-117
• /
• 2005

Limiting conditions for operations (LCOs) are evaluated dynamically using the tool of system dynamics. The LCOs de-fine the allowed outage times (AOTs) and the actions to be taken if the repair cannot be completed within the AOT. System dynamics has been developed to analyze the dynamic reliability of a complicated system. System dynamics using Vensim software have been applied to LCOs assessment for an example system, the auxiliary feed water system of a reference nuclear power plant. Analysis results of both full power operation and shutdown operation have been compared for a measure of core damage frequency. The framework developed in this study has been shown to be very flexible in that it can be applied to assess LCOs quantitatively under any operational context of the TS in FSAR.

• Journal of the Semiconductor & Display Technology
• /
• v.8 no.2
• /
• pp.59-62
• /
• 2009

In order to check the validation of LC simulation, 0.7 inch LCOS panel in full-HD resolution was fabricated and used for the electro-optical measurement. Compared the measured data with the calculated data, the averaged difference was 1.72% under 0 ~ +6 V bias on pixel electrode. To improve the optical characteristics of full-HD LCOS panel, the planar structure and trench structures (0.1 um, 0.2 um and 0.3 um-in-depth) between adjacent pixels were investigated with LC simulation. The planar structure showed the higher reflectance and faster reflectance-voltage response time than the trench structure. The optical fill factor and contrast ratio of planar structure were also higher than those of trench structures. As compared 1 um-in-depth trench structure resembled to the real structure with the planar structure, the optical fill factor was improved by 1.15% and the contrast ratio was improved by 5.26%. In order to minimize the loss of luminance and contrast ratio, the planar structure need to be applied between adjacent pixels.

• Transactions on Electrical and Electronic Materials
• /
• v.6 no.2
• /
• pp.73-77
• /
• 2005

In this study, we investigated response characteristics of liquid crystal display (LCD) with different operating mode of nematic liquid crystals (NLCs) such as 45 $^{circ} twisted nematic (TN), 67.3 $^{circ} TN and electrical controlled birefringence (ECB) on the rubbed polyimide (PI) surface with side chains. The pretilt angles generated on polyimide surfaces of the three kinds of LCD operating modes were about 12 $^{circ} that was higher than those of conventional TN-LCOs. Also, the Electro-optical (EO) performance of these LCOs showed stable condition. Low transmittance of the 45 $^{circ} TN and 67.3 $^{circ} TN cell on the rubbed PI surface were measured by using low cell gap d. The fast response time in ECB cell among the three kinds of LCD operating modes was achieved. Also, thermal ability of fast 90 $^{circ} TN-LCD was investigated. The threshold voltage and the response time of thermal stressed TN-LCOs showed the same performances on no thermal stressed TN-LCOs. There was little change of value in these TN cells. However, the transmittances of TN-LCOs on the rubbed PI surface decreased while increasing thermal stress time. Therefore, the thermal stability of TN-LCD was decreased by the high thermal stress for the long duration.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.112-116
• /
• 2006

In this presentation we will describe two core elements, which combination gives a new approach to layout verification; they are a computational algorithm for modeling of photolithographical processes and a method for physical layout verification that uses output contours of that algorithm. Utilization of this approach allows to improve the quality of LCOS/AM OLED backplanes physical verification, because it considers discrepancies between mask features and printed contours on a wafer.