• Title/Summary/Keyword: Liquid crystal lens

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Liquid Crystal Lens Array with Thermally Controllable Focal Length and Electrically Convertible Lens Type

  • Heo, Kyong Chan;Kwon, Jin Hyuk;Gwag, Jin Seog
    • Journal of the Optical Society of Korea
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    • v.19 no.1
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    • pp.88-94
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    • 2015
  • This paper reports the fabrication of a lenticular liquid crystal (LC) lens array with thermally tunable focus and with the function of a convertible lens type, using the surface structure of a UV-curable polymer and a twisted-nematic (TN) LC cell. The TN LC cell makes the LC lenticular lens function as a converging or diverging lens by controlling electrically the polarization of input light. Therefore, the focal lengths for both the converging and diverging lenses, which can be switched from the TN cell, can be tuned by changing the effective refractive index of the LC by Joule heating of the transparent electrode. As a result, the focal length of the lens with the E7 LC was changed continuously from 8.7 to 31.2 mm for the converging lens type and from -9.8 to -14.2 mm for the diverging lens when the temperature was increased from 25 to $56^{\circ}C$.

Optimal Design of Electric Field Driven Liquid Crystal Fresnel Lens Using Taguchi's Method (다구찌 실험계획법을 이용한 액정 전계 프레넬 렌즈의 최적 설계)

  • Kim, Bong-Sik;Kim, Jong-Woon;Park, Woo-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.25 no.3
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    • pp.218-223
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    • 2012
  • A rigorous electro-optical simulation and ray tracing for an electric field driven liquid crystal Fresnel lens was proposed to obtain design parameters of the electrode pattern of the Fresnel lens. The optimal design was carried out using Taguchi's experimental method for 17.1"($368{\times}229.5$ mm) wide LCD panels with 9 views. For the calculation of the distribution of liquid crystal molecules and the optical transmission of the panel, finite difference method and extended Jones matrix method were used to deal effectively with highly nonlinear and complicated motional equations of the liquid crystal molecules and to obtain the oblique transmission characteristics of the LCD panel. As simulation results, the optimal lengths of the 3 electrodes of the Fresnel lens are 4.0 ${\mu}m$, 30 ${\mu}m$ and 83 ${\mu}m$, respectively, and the locations of the second and third electrodes are 32.9-33.0 ${\mu}m$ and 45.9-46.0 ${\mu}m$, respectively. The optimal applied voltage of the 3 electrodes are found to be 5.75 V, 7.80 V and 11.9 V, respectively.

Analytical Study of the Image Reconstruction of Fourier Holograms Using Varifocal Electric-Field-Driven Liquid Crystal Fresnel Lenses

  • Kim, Taehyeon;Lee, Seung-Chul;Park, Woo-Sang
    • Current Optics and Photonics
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    • v.4 no.2
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    • pp.115-120
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    • 2020
  • A novel method is proposed for controlling the distance of an image plane in Fourier holograms using varifocal electric-field-driven liquid-crystal (ELC) lenses. Phase Fresnel lenses are employed to reduce the thickness and response time of the ELC lenses. The voltages applied to the electrodes of the ELC Fresnel lens are adjusted so that the lens has the same retardation distribution as an ideal lens. The focal length can be controlled by changing the retardation distribution with the applied voltages. Simulations were conducted for the image reconstruction of Fourier holograms with various focal lengths of the ELC Fresnel lenses. The simulation results indicate that the distance of the image plane can be properly controlled with the varifocal ELC Fresnel lens.

The Analysis of position Sensitivity and Aberration characteristics of Liquid Crystal Elements (액정 소자의 위치 민감도 및 수차 특성에 대한 연구)

  • Heor Jae-Youn;Yoo Ho-Sik;Yoo Jang-Hoon;Park Soo Han;Jeong Soo-Jin
    • Transactions of the Society of Information Storage Systems
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    • v.1 no.1
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    • pp.78-83
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    • 2005
  • The Blu-ray disc as a next generation high density optical medium uses an objective lens of high numerical aperture(NA 0.85) and blue laser in order to increase the recording density. The double layer is also useful for doubling the density. The spherical aberration of Blu-ray disc is very sensitive to the thickness of the disk because of high numerical aperture. This paper suggests a method to compensate the spherical aberration caused by the change of disk thickness, by using the Liquid Crystal lens instead of the Liquid Crystal panel. It was possible to develop both the LC panel generating the optical phase difference and LC lens changing the optical power. In this paper, we analyzed the aberration performance and a position sensitivity of the two type LC elements when the samples deviate from the optical axis of the objective lens. The results of applying this analysis show that the LC lenses rather than the LC panels have a significant assembling tolerance. The theoretical characteristics of the two elements are calculated and compared with the measurement data.

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Design and Fabrication of Variable Focusing Lens Arrays (VFLA) using Liquid Crystal for Integral photography(IP)

  • Hwang, Yong-Seok;Yoon, Tae-Hoon;Kim, Jae-Chang
    • 한국정보디스플레이학회:학술대회논문집
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    • 2003.07a
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    • pp.1034-1037
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    • 2003
  • In this work, Integral photography with variable focusing lens arrays is proposed. We fabricate two-dimensional liquid crystal lens arrays using cohesion of UV curable polymer and lithography. Applied voltage to the cell alters the effective refractive index of the liquid crystal layer and results in a change of the focal length. By adjusting the focal length, synchronized elemental image array for real or virtual mode is integrated in front of or behind the lens array.

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Color-Matching Liquid Crystal Display using a Lenticular Lens Array and RGB Light Sources

  • Jeon, Hwa Joon;Park, Gyeungju;Gwag, Jin Seog;Lee, Jong Hoon;Kwon, Jin Hyuk
    • Journal of the Optical Society of Korea
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    • v.18 no.4
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    • pp.345-349
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    • 2014
  • A direct-lit color-matching liquid crystal display using a lenticular lens array with grouped lens elements that image linear RGB light sources on the RGB subpixels of a color filter to enhance transmittance is designed, simulated, and fabricated. The RGB LED linear light sources were fabricated using small RGB LEDs in a linear array arrangement, and the lenticular lens array consisted of eight units of the same structure with a gap of 2.19 mm. The optical transmittance of the liquid crystal panel was improved by as much as 240% due to the color matching.

A Review of Electrically Tunable Focusing Liquid Crystal Lenses

  • Lin, Hung-Chun;Chen, Ming-Syuan;Lin, Yi-Hsin
    • Transactions on Electrical and Electronic Materials
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    • v.12 no.6
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    • pp.234-240
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    • 2011
  • Electrically tunable focusing liquid crystal (LC) lenses are reviewed in this paper. The distribution of the orientations of LC directors which is controlled by electric fields results in a distribution of refractive indices of LC directors. The incident light can be modulated by the electrically tunable lens-like phase difference of the LC lens. We introduce the basic operating principles of LC lenses and discuss the structures of LC lenses. The major challenges of LC lenses are also discussed. We believe this paper provides a guideline for basic understanding of LC lenses.

Rigorous Analysis of Viewing Zone for 3D Display with Electric-field-driven Liquid Crystal Lens (액정 전계 렌즈 기반 3차원 디스플레이 장치의 엄정한 시청영역 분석)

  • Kim, Tae-Hyeon;Kim, Bong-Sik;Park, Woo-Sang
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.29 no.8
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    • pp.494-498
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    • 2016
  • In this paper, we proposed the 3-dimenstional (3D) analysis for calculating the optical characteristics of an autostereoscopic display with electric field driven liquid crystal (ELC) lens. From 3D analysis considering the slanting of lens, we calculate the cross-talk of each images and the distortion of viewing zone. Using geometric opics and extended Jones matrix method (EJMM), phase retardation of ELC lens according to position is calcuated and then optical path difference in 3D space considering tilt and azimuth angle of incident light is gotten. Then, intensity distribution is presented in the space. Through camparing the intensity distribution using ideal lens with the ELC lens, we identify the noise and image distortion of ELC lens. As a result, this analysis is expected to provide optimum design conditions for realistic and rigorous 3D display with ELC lens.

An integrated elastomer substrate with a lens array and pixel elements for three-dimensional liquid crystal displays

  • Hong, Jong-Ho;Kim, Yeun-Tae;Kim, Yun-Hee;Lee, Byoung-Ho;Lee, Sin-Doo
    • Journal of Information Display
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    • v.13 no.2
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    • pp.55-59
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    • 2012
  • In this paper, a concept of an integrated elastomer substrate for a three-dimensional (3D) liquid crystal display based on the integral-imaging method is presented. The elemental lens array and columnar spacers were integrated into one of the two substrates, an elastomer substrate, through an imprinting process. The integrated elastomer substrate was capable of maintaining the uniform liquid crystal (LC) cell gap and promoting homeotropic LC alignment without any surface treatment. The monolithic approach reported herein will provide a key component for 3D displays with enhanced portability through a more than 40% weight reduction compared with the conventional integral-imaging method.

A study on liquid crystal-based electrical polarization control technology for polarized image monitoring device (편광 영상감시 장치를 위한 액정 기반 전기적 편광 조절 기술 연구)

  • Ahn, Hyeon-Sik;Lim, Seong-Min;Jang, Eun-Jeong;Choi, Yoonseuk
    • Journal of IKEEE
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    • v.26 no.3
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    • pp.416-421
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    • 2022
  • In this study, we present a fully automated system that combines camera technology with liquid crystal technology to create a polarization camera capable of detecting the partial linear polarization of light reflected from an object. The use of twisted nematic (TN) liquid crystals that electro-optically modulate the polarization plane of light eliminates the need to mechanically rotate the polarizing filter in front of the camera lens. Images obtained using these techniques are imaged by computer software. In addition, liquid crystal panels have been produced in a square shape, but many camera lenses are usually round, and lighting or other driving units are installed around the lens, so space is optimized through the application of a circular liquid crystal display. Through the development of this technology, an electrically switchable and space-optimized liquid crystal polarizer is developed.