• Title/Summary/Keyword: Optical path shift

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A Study on the Retina shaped Optical Path Shift Using the Prism

  • Kwon Yun Jung;Nam Sang Yep;Lee Sung Chang
    • Proceedings of the IEEK Conference
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    • 2004.08c
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    • pp.699-702
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    • 2004
  • This paper discusses about the mechanism of catching an image through an optical manipulation of each organizations in the eye, more specifically, mechanism of catching an image on a retina through a Camera and a Crystal Lens. In the retina, the macula roles as a fovea contrails and it leads the image which is about 3 mm to be shaped on there. However, even the macula may not properly function, our eyes still can catch the image by shifting the optical path to around of the macula, even if the sensitivity of the image is generally lower than the image on the macula. This paper proposes a method of shifting the shaped image on the retina by refracting the optical path through a prism located on the rear of a screen which consists of a 0.7' TFT LCD. Applying this method that throwing an image around on the macula, central visual disturbance patients among retinitis pimentos patients can expect to recover such a mechanism to catch an image.

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Implementation of real-time optical pattern recognition system using a photorefractive correlator with improved shift-invariant property (변이불변 특성이 개선된 광굴절 상관기를 이용한 실시간 광 패턴인식 시스템 구현)

  • 김성완;김철수;김종찬;김종윤;이승희;김수중
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.35D no.3
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    • pp.63-69
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    • 1998
  • In this paper, a new input method is proposed to improve shift-invariant property of a photorefractive correlator andwe implemented real-time optical pattern recognition system using it. In the conventional photorefractive correlator, it is vrey difficult to satisfy the Bragg condition in the pattern recognition process. So, correlation peak is decreased heavily for the shift of input image. If a liquid crystal television(LCTV) without an anlyzer is used as input device, we can get the correlation result regardless of shift of input image because beam path is not changed during storage of holographic filter and correlation process. Also recording time of a holographic matched filter in photorefractive crystal is reduced and the correlation peak is increased because incident beam on the LCTV is transmitted completely. Therefore total optical efficiency is improved. We compared and analyzed the correlation results of proposed photorefractive correlator by computer simulation and optical experiment. We used a BaTiO$_{3}$ single crystal which has high diffraction efficiency in optical experiment.

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The Chracteristics of Wavelength Shift in Fiber Ring Laser Tuned by Polarization Control (편광제어에 의한 파장가변 고리형 광섬유레이저에서의 파장천이특성)

  • 김익상
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.9B
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    • pp.1534-1541
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    • 2000
  • Wavelength tunable fiber ring laser can be tuned by causing a resonance on the optical path having the least loss which is controlled by a polarization adjustment. It is observed that lasing wavelengths having 1 nm FSR(Free Spectral Range) can be tuned over the range of 1540-1560 nm when a polarization controller and an intra-cavit polarizer with 1.5 mm air gap are adjusted. The characteristics of wavelength shift in the laser output are analyzed by introducing an optical path modeling and the concept of a birefringence loss.

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Precise Measurement of the change n the optical length of a fiber Fabry-Perot interferometer. (광섬유 Fabry-Perot 간섭계를 이용한 위상 변화량의 정밀 측정)

  • 김영준
    • Proceedings of the Optical Society of Korea Conference
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    • 1989.02a
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    • pp.113-118
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    • 1989
  • By using the single mode optical fiber, we fabricated Fiber-optic Fabry-Perot interferometer (FFPI). The change over a wide range in the optical path length of a FFPI is observed. The temporal movement of the interference fringes by external condition to P.Z. T) is converted to circular motion on an oscilloscope display and then recorded with a micro-computer. The two output voltages of the D/A converters are applied to X and Y terminals of oscilloscope to display circular motion on oscilloscope. Thus the direction of phase shift can be determined with observing the direction of circular motion. The variation of the optical length can be measured by calculating the angle of spot of circle with an accuracy of λ/90 wave length due to variation of temperature in this system 2.7x10-4$^{\circ}C$.

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Design and Fabrication of Aspherical Optical System for Augmented Reality Application (증강 현실 응용을 위한 비구면 광학계 설계 및 제작)

  • Chang-Won Shin;Hyeong-Chang Ham;Ae-Jin Park;Hee-Jae Jung;Kang-Hwi Lee;Chi-Won Choi
    • Korean Journal of Optics and Photonics
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    • v.34 no.4
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    • pp.157-169
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    • 2023
  • Augmented reality (AR) using a head mounted display (HMD) is used in various fields such as military, medicine, manufacturing, gaming, and education. In this paper, we discuss the design and fabrication of the AR optical system, which is most essential for HMD. The AR optical system for HMD requires a wide transparent area in which the augmented image of the display and the real world can be viewed at the same time. To this end, an AR optical system was designed and manufactured by dividing it into three parts according to each characteristic. Also, the refractive index of the ultra-violet (UV) adhesive layer required to make the three optical systems into one complete AR optical system was considered from the design stage to minimize the optical path shift phenomenon when the input light source passes through the UV adhesive layer. In addition, when designing the AR optical system, two aspheric surfaces were used to compensate for off-axis aberration and to be suitable for mass production. Finally, for HMD mass production, an aspheric AR optical system with a thickness of 11 mm, a diagonal field of view of 40°, and a weight of 11.3 g was designed and manufactured.

2-D/3-D Combined Algorithm for Automatic Solder Paste Inspection (솔더 페이스트 자동검사를 위한 2-D/3-D 복합 알고리즘)

  • 조상현;이상윤;임쌍근;최흥문
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.173-176
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    • 2002
  • In this paper, we present the combined 2-D and 3-D algorithms for automatic solder paste inspection. For automatic inspection, optical system for the combined inspection and driving unit is made. One-pass run length algorithm that has fast and efficient memory space is applied to the input image fur extracting solder paste patterns. The path of probe movement is then calculated for an automatic inspection. For a fast 3-D inspection, the phase shift algorithm based on Moire interferometry is also used. In addition, algorithms used in this paper are coded by $MMX^{TM}$. A probe system is manufactured to simultaneously inspect 2-D and 3-D for 10mm$\times$10mm field of view, with resolutions of 10 $\mu\textrm{m}$for both x, y axis and 17 $\mu\textrm{m}$for z axis, and then, experiments on several PCBs are conducted. The processing times of 2-D and 3-D, excluding an image capturing, is 0.039 sec and 0.047 sec, respectively. The credible result with $\pm$ 1$\mu\textrm{m}$uncertainty can be also achieved.

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A Study on Visible Light Communication with Turbo Coded OFDM for Intelligent Transport Systems (지능형 교통 시스템을 위한 Turbo Code OFDM 적용한 가시광 통신 시스템에 관한 연구)

  • Koo, Sung-Wan;Kim, Jin-Young
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.9 no.2
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    • pp.60-67
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    • 2010
  • In the ubiquitous age, applications of wireless personal area network (WPAN) technology using LEDs are in progress. However, visible light communications (VLC) using the LEDs have weakness which deteriorate performance of communication because of multi-path fading that occurs propagation delay by interior walls or other things in indoor environments. In this paper, orthogonal frequency division multiplexing (OFDM) scheme is adapted to decrease multi-path fading and multi-path dispersion and to provide high speed data transmission. Besides, to reduce information losses caused by optical noise (incandescent lamps, fluorescent lamps, sunbeam etc.) also proposed channel coding using turbo codes. The encoding and decoding of the proposed system is described, and simulation results are analyzed. We can know that performance of proposed system is increased about 4 [dB] through the simulation results. Also, when the system take doppler effect, the system performance worsened.

Thickness and Angle Dependent Microcavity Properties in Top-Emission Organic Light-Emitting Diodes (상부 발광 유기 발광 소자에서 두께와 시야각에 따른 마이크로 캐비티 특성)

  • Lee, Won-Jae
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.1
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    • pp.32-35
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    • 2011
  • Top-emission device has a merit of high aperture ratio and narrow emission spectrum compared to that of bottom-emission one. Emission spectra of top-emission organic light-emitting diodes depending on a layer thickness and view angle were analyzed using a theory of microcavity. Device structure was manufactured to be Al (100 nm)/TPD/$Alq_3$/LiF (0.5 nm)/Al (2 nm)/Ag (30 nm). N,N'-diphenyl-N,N'- di (m-tolyl)-benzidine (TPD) and tris (8-hydroxyquinoline) aluminium (Alq3) were used as a hole-transport layer and emission layer, respectively. And a thickness of TPD and Alq3 layer was varied in a range of 40 nm~70 nm and 60 nm~110 nm, respectively. Angle-dependent emission spectrum out of the device was measured with a device fixed on a rotating plate. Since the top-emission device has a property of microcavity, it was observed that the emission spectrum shift to a longer wavelength region as the organic layer thickness increases, and to a shorter wavelength region as the view angle increases. Layer thickness and view-angle dependent emission spectra of the device were analyzed in terms of microcavity theory. A reflectivity of semitransparent cathode and optical path length were deduced.

An implementation of 2D/3D Complex Optical System and its Algorithm for High Speed, Precision Solder Paste Vision Inspection (솔더 페이스트의 고속, 고정밀 검사를 위한 이차원/삼차원 복합 광학계 및 알고리즘 구현)

  • 조상현;최흥문
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.41 no.3
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    • pp.139-146
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    • 2004
  • A 2D/3D complex optical system and its vision inspection algerian is proposed and implemented as a single probe system for high speed, precise vision inspection of the solder pastes. One pass un length labeling algorithm is proposed instead of the conventional two pass labeling algorithm for fast extraction of the 2D shape of the solder paste image from the recent line-scan camera as well as the conventional area-scan camera, and the optical probe path generation is also proposed for the efficient 2D/3D inspection. The Moire interferometry-based phase shift algerian and its optical system implementation is introduced, instead of the conventional laser slit-beam method, for the high precision 3D vision inspection. All of the time-critical algorithms are MMX SIMD parallel-coded for further speedup. The proposed system is implemented for simultaneous 2D/3D inspection of 10mm${\times}$10mm FOV with resolutions of 10 ${\mu}{\textrm}{m}$ for both x, y axis and 1 ${\mu}{\textrm}{m}$ for z axis. Experiments conducted on several nBs show that the 2D/3D inspection of an FOV, excluding an image capturing, results in high speed of about 0.011sec/0.01sec, respectively, after image capturing, with $\pm$1${\mu}{\textrm}{m}$ height accuracy.