• Title/Summary/Keyword: optical memory devices

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Analysis of Driving Characteristics and Memory Effect by Occupation Area Evaluation Method of Charged Particle Type Display Device (대전입자형 디스플레이 소자의 점유면적 평가방법에 의한 구동특성 및 메모리 효과 분석)

  • Kim, Jin-Sun;Kim, Young-Cho
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.8
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    • pp.669-673
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    • 2011
  • The charged particle type display is a kind of the reflectivity type display and shows an image by absorption and reflection of external light source, which has keep an image without additional electric power because of bistability. In this paper, we made a device whose cell gap is $56\;{\mu}m$ and also analyzed driving and memory characteristics by applied driving voltages. As a result, we found that the driving voltage and memory effect depend on q/m(charge to mass ratio) of charged particle. In this case of breakdown voltage, the devices showed degradation of reflectivity and memory effect due to irregular movement of overcharged particles. In addition, contrast ratio of the device varies with memory effect. Thus, we consider that device needs uniform q/m for improvement of electric and optical properties and memory effect.

Proposal and Characterization of Ring Resonator with Sharp U-Turns Using an SOI-Based Photonic Crystal Waveguide

  • Omura, Yasuhisa;Iida, Yukio;Urakawa, Fumio;Ogawa, Yoshifumi
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.7 no.2
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    • pp.102-109
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    • 2007
  • We propose and experimentally demonstrate a ring resonator with sharp U-turns fabricated on a silicon-on-insulator (SOI) substrate; the resonator was designed as a key part of an optical, dynamic data storage device. We discuss the optical properties of the fabricated ring resonator from the viewpoint of equi-frequency-contour behavior in a dispersion space. We successfully characterize its optical characteristics on the basis of photonic crystal physics. It is suggested that the photonic ring resonator will be applicable to optical, dynamic memory devices for optical communication systems.

Characterization of Spironaphthooxazine Derivative Thin Films for Optical Memory

  • Kang, Young-Soo;An, Sang-Do;Jang, Ju-Seog;Kim, Byung-Kyu;Kim, Yong-Joo
    • KIEE International Transactions on Electrophysics and Applications
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    • v.11C no.3
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    • pp.49-52
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    • 2001
  • The derivatives of spironaphthooxazine gause photoisomerization when they are illuminate with UV light. We investigated the photoisomerization of spironaphthooxazine derivatives for holographic memory. Langmuir-Blodgett (LB) films contain amphiphile spironaphthooxazine derivatives which can be applied in molecular devices by a change of molecular level energy and a refractive index. In order to investigate the photoisomerization of spironaphthooxazine derivatives at the air/water energy and a refractive index. In order to investigate the photoisomerization of spironaphthooxazine derivatives at the air/water interfaces, spironaphthooxazine derivatives with side alkyl chains were synthesized. The films of the spironaphthooxazine derivatives were characterized by the measurement of UV/vis spectroscopy, Brewster Angle Microscopy (BAM) and Atomic Force Microscopy (AFM). The monolayers of the spironaphthooxazine derivatives mixed with stearic acid were stable at the air/water interface and visualized by the measurement of BAM. The spironaphthooxazine derivative monolayers on the glass surface showed the maximum efficiency of diffraction as 0.99% by the measurement of holography.

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Antifuse Circuits and Their Applicatoins to Post-Package of DRAMs

  • Wee, Jae-Kyung;Kook, Jeong-Hoon;Kim, Se-Jun;Hong, Sang-Hoon;Ahn, Jin-Hong
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.1 no.4
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    • pp.216-231
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    • 2001
  • Several methods for improving device yields and characteristics have been studied by IC manufacturers, as the options for programming components become diversified through the introduction of novel processes. Especially, the sequential repair steps on wafer level and package level are essentially required in DRAMs to improve the yield. Several repair methods for DRAMs are reviewed in this paper. They include the optical methods (laser-fuse, laser-antifuse) and the electrical methods (electrical-fuse, ONO-antifuse). Theses methods can also be categorized into the wafer-level(on wafer) and the package-level(post-package) repair methods. Although the wafer-level laser-fuse repair method is the most widely used up to now, the package-level antifuse repair method is becoming an essential auxiliary technique for its advantage in terms of cost and design efficiency. The advantages of the package-level antifuse method are discussed in this paper with the measured data of manufactured devices. With devices based on several processes, it was verified that the antifuse repair method can improve the net yield by more than 2%~3%. Finally, as an illustration of the usefulness of the package-level antifuse repair method, the repair method was applied to the replica delay circuit of DLL to get the decrease of clock skew from 55ps to 9ps.

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1-Axis Actuator for Compensating Focus Error and SA due to the Variation of Cover-Layer Thickness in Small-Form-Factor Optical Disk (초소형 광디스크의 보호층 두께 편차 보상용 1축 엑츄에이터)

  • Park, Jin-Moo;Hong, Sam-Nyol;Choi, In-Ho;Kim, Jin-Yong
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2004.11a
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    • pp.227-231
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    • 2004
  • Technological advance in information technology has sparked the necessity of small form factor (SFF) optical disk for mobile devices. Small form factor optical disk is highly anticipated to be a next generation storage device because it can be used for a cost-effective way compared with solid state memory. For the application to the 5 mm height small-form-factor optical disk drive, we have presented an optical flying head and swing arm actuator. In this study, we propose a small 1-axis actuator for compensating ficus error and SA due to the variation of cover-layer thickness in the cover-layered small optical disk. The main design issues of the 1-axis actuator are the realization of compact structure and the new support structure of the actuator: Finally, the compensating principle and performance of the 1-axis actuator will be explained.

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Key issues in optics for optical memory devices (광기억장치에서의 핵심 광학기술연구)

  • 이철우
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.02a
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    • pp.28-29
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    • 2000
  • 최근, 통신, PC등의 보급과 함께, 메모리기기의 발전이 급속히 이루어 지고있다. 이 중에서 광기억장치는 기록 및 재생용량을 증가시키는 기술이 활발히 연구되어 왔다. 본고에서는 대용량기기의 대표적인 DVD(Digital Versatile Disc)에 있어서, 핵심광학기술로 각광을 받고있는 CD호환을 위한 환형(annular type) lens의 특성을 고찰하였다. 그리고, 반도체 메모리, Hard disk등도 고밀도연구가 지속적으로 연구되고있으며, 이에 대응되는 광기억장치의 기술로서 근접장 광학이 최근 활발히 연구되고있다. 근접장에 의한 고개구수를 달성하기 위한 효율적인 대물렌즈로서 종래의 굴절렌즈만이 아닌 반사광학계도 사용한 굴절-반사광학계 (Cata-dioptric Optics)를 응용한 Solid Immersion Mirror (SIM)에 관한 특성을 살펴보았다. (중략)

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Stress Induced Gigantic Piezoelectricity of PZT thin films for Actuated Mirror Array

  • Suzuki, Hisao
    • 한국정보디스플레이학회:학술대회논문집
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    • 2006.08a
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    • pp.591-596
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    • 2006
  • Lead zirconate titanate(PZT) thin films have been attracting worldwide interests in exploring their potential properties [1-3] or the origins [4-6] of their excellent dielectic, ferroelectric and piezoelectric properties near the morphotropic phase boundary (MPB). PZT thin films are expected to apply to the memory devices, micro electro mechanical systems (MEMS), and display because of their superior ferroelectric, pyroelectric, piezoelectric and electron emission properties. In this study, high- performance piezoelectric PZT thin films for actuated mirror array and optical scanner were developed by controlling the several factors, such as molecular-designed precursor, seeding layer and the residual stress in films, by a chemical solution deposition (CSD).

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Electrochromic Device for the Reflective Type Display Using Reversible Electrodeposition System

  • Kim, Tae-Youb;Cho, Seong M.;Ah, Chil Seong;Suh, Kyung-Soo;Ryu, Hojun;Chu, Hye Yong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.232.1-232.1
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    • 2014
  • The green displays are the human friendly displays, the nature friendly displays, and the economical displays. Electrochromic displays are low cost and environmental devices because they do have more choice of colours and use much less power. The elements of the electrochromic devices consist of at least two conductors, an electrochromic material and an electrolyte. The optical properties were obtained using the optical contrast between the transparency of the substrate and the coloured state of the electrochromic materials. These devices can be fully flexible and printable. Due to the characteristics of the high coloration efficiency and memory effects, the electrochromic devices have been used in various applications such as information displays, smart windows, light shutters and electronic papers. Among these technical fields switchable mirrors have been received much attention in the applicative point of view of various electronic devices production. We have developed a novel silver (Ag) deposition-based electrochromic device for the reversible electrodeposition (RED) system. The electrochromic device can switch between transparent states and mirror states in response to a change in the applied voltage. The dynamic range of transmittance percent (%) for the fabricated device is about 90% at 550 nm wavelength. Also, we successfully fabricated the large area RED display system using the parted electrochromic cells of the honey comb structure.

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Resistive Memory Switching in Ge5Se5 Thin Films

  • Kim, Jang-Han;Hwang, Yeong-Hyeon;Chung, Hong-Bay
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.326-326
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    • 2014
  • It has been known since the mid 1960s that Ag can be photodissolved in chalcogenide glasses to form materials with interesting technological properties. In the 40 years since, this effect has been used in diverse applications such as the fabrication of relief images in optical elements, micro photolithographic schemes, and for direct imaging by photoinduced Ag surface deposition. ReRAM, also known as conductive bridging RAM (CBRAM), is a resistive switching memory based on non-volatile formation and dissolution of a conductive filament in a solid electrolyte. Especially, Ag-doped chalcogenide glasses and thin films have become attractive materials for fundamental research of their structure, properties, and preparation. Ag-doped chalcogenide glasses have been used in the formation of solid electrolyte which is the active medium in ReRAM devices. In this paper, we investigated the nature of thin films formed by the photo-dissolution of Ag into Ge-Se glasses for use in ReRAM devices. These devices rely on ion transport in the film so produced to create electrically programmable resistance states [1-3]. We have demonstrated functionalities of Ag doped chalcogenide glasses based on their capabilities as solid electrolytes. Formation of such amorphous systems by the introduction of Ag+ ions photo-induced diffusion in thin chalcogenide films is considered. The influence of Ag+ ions is regarded in terms of diffusion kinetics and Ag saturation is related to the composition of the hosting material. Saturated Ag+ ions have been used in the formation of conductive filaments at the solid electrolyte which is the active medium in ReRAM devices. Following fabrication, the cell displays a metal-insulator-metal structure. We measured the I-V characteristics of a cell, similar results were obtained with different via sizes, due to the filamentary nature of resistance switching in ReRAM cell. As the voltage is swept from 0 V to a positive top electrode voltage, the device switches from a high resistive to a low resistive, or set. The low conducting, or reset, state can be restored by means of a negative voltage sweep where the switch-off of the device usually occurs.

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New Azo Polymers and Their Applications to High Density Optical Memory Devices

  • Han, Yang-Kyoo;Lee, Min-Jeong
    • Proceedings of the Polymer Society of Korea Conference
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    • 2006.10a
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    • pp.169-169
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    • 2006
  • Novel liquid crystalline malonic ester monomers were synthesized from malonyl dichloride and mesogenic alcohols as a photoresponsive group. The monomers were polymerized with aliphatic or aromatic dibromides in the presence of sodium hydride to give 8 kinds of novel poly(malonic esters) with two symmetrical azobenzene groups. We found that the resulting polymer films could be used as rewritable optical data storage (or holographic image) media through a photoisomerization of azobenzene group by Ar laser irradiation. The sensitivity of data recording was dependent not only on the thickness of the polymeric thin film but also on the intensity of laser beam.

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