• Journal of Information Display
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• v.11 no.2
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• pp.76-83
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• 2010

This paper presents the multi-user autostereoscopic 3D display system constructed and operated by the authors using the time-multiplexing approach. This prototype has three main advantages over the previous versions developed by the authors: its hardware was simplified as only one optical array is used to create viewing regions in space, a lenticular multiplexing screen is not necessary as images can be produced sequentially on a fast 120Hz LCD with full resolution, and the holographic projector was replaced with a high-frame-rate digital micromirror device (DMD) projector. The whole system in this prototype consists of four major parts: a 120Hz high-frame-rate DMD projector, a 49-element optical array, a 120Hz screen assembly, and a multi-user head tracker. The display images for the left/right eyes are produced alternatively on a 120Hz direct-view LCD and are synchronized with the output of the projector, which acts as a backlight of the LCD. The novel steering optics controlled by the multiuser head tracker system directs the projector output to regions referred to as exit pupils, which are located in the viewers’eyes. The display can be developed in the "hang-on-the-wall"form.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.714-719
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• 2014

A pico-projector is a compact and mobile projector that has an infinite focus. We apply the pico-projector to a projection-type integral imaging system, which can expand the image depth to form multiple central depth planes. In a projection-type integral imaging system, the image flipping problem arises because the expanded elemental images pass through a lens array. To solve this problem, we propose the ray tracing of a pico-projector at a central depth plane and compensate the elemental image using a pixel-mapping process. Experiments to verify the proposed method are performed, and the results are presented.

• International Journal of Precision Engineering and Manufacturing
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• v.1 no.1
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• pp.98-105
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• 2000

The projectors using liquid crystal display(LCD) have faults such as low optical efficiency, low brightness and even heat generation. To solve these problems reflective-type spatial light modulators based on MEMS (Microelectromechanical Systems) technology have emerged. Digital Micromirror DeviceTM(DMDTM), which was already developed by Texas Instruments Inc., and Thin-film Micromirror ArrayTM(TMATM), which has been recently developed by Daewoo Electronics Co., are the representative examples. The display using TMATM has particularly much higher optical efficiency than other projectors. But the micromirrors manufactured by semiconductor processes have inevitable distortion because of the limitations of the manufacturing processes, so that the distortions of their surfaces have great influence on the optical efficiency of the projector. This study investigated the effects of mirror flatness on the optical performance, including the optical efficiency, of the TMATM projector. That is to say, as a part of the efforts to enhance the performance of the TMATM projector, how much influence the form errors of a micromirror surface exert on the optical efficiency and the modulation of gray scale of the projector were analyzed through a pertinent modeling and simulations.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.2
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• pp.221-233
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• 2017

The array equations are commonly used for analysis and conceptual design of active sonar projector arrays. Calculation of the radiation impedance matrix poses a major computational bottleneck for the solution of the array equations, which leads to a dramatic increase in computational load as the number of constituent transducers increases. Here, we propose an iteration-based solution method that does not require the calculation of the radiation impedance matrix, as a computationally efficient alternative to the status quo. The validity of the iteration-based analysis is judged against the full finite-element analysis that includes the entire array as well as the medium. The array equations for the 1/3-sector of a cylindrical array comprised of 48 Tonpilz transducers are augmented by the lumped element models, and are solved iteratively for the acoustic and electro-mechanical characteristics. The iteration-based analysis exhibits rapid convergence and accuracy comparable with the FE analysis. Simulations also reveal that the acoustic coupling between transducers has more pronounced effects on the electro-mechanical characteristics of individual transducers than the acoustic performance of the array.

• 전기의세계
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• v.45 no.9
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• pp.37-41
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• 1996

MEMS 기술에 의해 개발되고 있는 많은 제품들 가운데 가장 잠재력 있고 큰 시장을 가진 대형 projector의 개발은 핵심 chip이 현재 DMD(Digital Micromirror Device), AMA(Actuated Mirror Array), 그리고 GLV(Grating Light Valve) 방식으로 진행되고 있으며 TI사가 개발 중인 DMD projector가 상품화에 근접해 있으며 고화질의 시제품을 SID(Society for Information Display) 국제 전시회에 출품하여 전세계 연구원들의 이목을 끌었으며 앞으로 어떻게 수율을 높이고 광학계의 단순화를 이루어 제작비를 낮추는 가가 관심의 초점이다. MEMS 연구를 하는 한 사람으로서의 사견으로도 이 제품이 성공하여야 범세계적으로 일어나고 있는 MEMS 기술이 더욱 확실한 신기술로서의 지위를 갖고 연구되리라 믿는다.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1427-1429
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• 2008

In this paper, an illumination system design using two lamps was proposed to improve the brightness of the projector. The proposal is based on the results from optical simulation. The prism array was applied to maintain the same optical properties, such as brightness distribution for the divergence angle and the composed beam size of the system. These were compared to those of the one UHP lamp system. The brightness of the two-lamp system, having a panel size of 0.74" and an f/2.9, increased by a factor of 1.7 when compared to the brightness of one UHP lamp system.

• Journal of Information Display
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• v.11 no.1
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• pp.28-32
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• 2010

A mini-projector prototype employing a LED light source, a nontelecentric structure, and an LCOS panel for application in the integrated 3D display was fabricated. A seamless image was obtained by tilting an array of mini-projectors. Seamless quality was created by the excellent uniformity of the projection intensity on the mini-projector's screen, which was simulated as 98.34%. Great uniformity can be realized by optimizing the design of the light source and the optics configuration, which is the key to such realization.

• Electrical & Electronic Materials
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• v.9 no.7
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• pp.745-754
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• 1996

이글에서는 다음의 내용을 다루었다. 1. LCD의 기능 성능 향상, (1) CRT와 TFT-LCD의 기능, 성능 비교, (2) TFT-LCD의 기능, 성능향상을 위한 과제 2. TFT-LCD의 가격 및 수급현황 3. Poly-Si TFT-LCD전망 4. 투사형 TFT-LCD 5. 반사형 LCD 6. 필림형 LCD 7. 고분자 분산형 액정(PDLC)

• Korean Journal of Optics and Photonics
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• v.26 no.4
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• pp.226-232
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• 2015

A double-layer LED array together with an illumination optical system is proposed as a possible light source for LC projection display systems for large screens, up to $8m{\times}6m$ (400 inches diagonal). The heat dissipation problem of the LED array is solved by arranging the LEDs in double layers, and thermal analysis shows its effectiveness. The light from the LEDs in the back layer can be transmitted through the front layer without significant loss by arranging the LEDs in non-overlapping positions in the two layers and inserting suitable microlenses between the two layers and holes in the first layer. Together with the double-layer LEDs, an illumination optical system is designed to illuminate liquid crystal panels with good uniformity and appropriate matching with the projection optics.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.2
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• pp.116-124
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• 2011

A service robot can identify its own position relative to landmarks, the locations of which are known in advance. The main contribution of this research is that it gives various ways of making the self-localizing error smaller by referring to special landmarks which are developed as high gain reflection material and coded array associations. In this paper, the authors propose a set of indices to evaluate the accuracy of self-localizing methods using the selective reflection landmark and infrared projector, and the indices are derived from the sensitivity enhancement using 3D distortion calibration of camera. And then, the accurarcy of self-localizing a mobile robot with landmarks based on the indices is evaluated, and a rational way to minimize to reduce the computational cost of selecting the best self-localizing method. The simulation results show a high accuracy and a good performance.