HyungKi Hong

25.3: Autostereoscopic 2D/3D Switching Display Using Electric-Field-Driven LC Lens (ELC Lens)

We propose a new 2D/3D switching method using the lens effect solely caused by LC director distribution under controlled non-uniform electric field distribution. By optimizing electrodes structure and applying this lens cell to LCD of 17.1 inches size in diagonal, we successfully verified the lens on/off effect of LC lens and the switching between an auto-stereoscopic 9-view 3D mode and a clear 2D mode. Comparing with previously reported structures of other switching lens, our proposed structure is the most competitive in respect of structure simplicity and process compatibility.

Electric‐field‐driven LC lens for 3‐D/2‐D autostereoscopic display

— The use of an electric-field-driven liquid-crystal (ELC) lens cell for switching between a 3-D and 2-D display is proposed. Due to the phase retardation of the non-uniform LC directors, an ELC lens functions the same as a geometric lens. The parameters of an ELC for 3-D applications are optimized through the simulation of the electrode configuration and voltage levels. A prototype was made where the ELC lens is placed in front of a liquid-crystal display (LCD) 15 in. on the diagonal with a 99-μm subpixel pitch. Under zero voltage, the ELC lens is a transparent medium and the users can see a clear 2-D image. In 3-D mode, the ELC lens array performs the same as a cylindrical lens array to the incident vertical polarization under suitable driving voltages. Placing a half-wave plate between the LCD and ELC lens is proposed to change the polarization of the LCD to be parallel with the polarization lens direction of the ELC lens. The measurement of the horizontal luminance profile, performance of the ELC lens, and feasibility for 3-D/2-D switching was verified. The fabrication process for the ELC lens is compatible with the current LCD production process and enables the accurate control of the lens pitch of the ELC lens.

Analysis of angular dependence of 3‐D technology using polarized eyeglasses

— The cause of the angular dependence of 3-D technology that requires the use of eyeglasses with linear or circular polarization is analyzed. For 3-D technology that requires the use of eyeglasses, anisotropic media such as a polarizer or retardation film determines the polarization state. Therefore, the angular behavior of 3-D display performance is also affected by the characteristics of the anisotropic media that have intrinsic angular dependence. Various conditions of the optic axes of the imaging display and eyeglasses are investigated to understand their effect on 3-D display performance. The result shows that some conditions of the optic axes can cause non-negligible degradation of 3-D display performance.

20.1: Mobile 3D Displays Based on a LTPS 2.4” VGA LCD Panel Attached with Lenticular Lens Sheets

We developed the prototypes of 2-view and multi-view 3D displays based on LTPS 2.4″ VGA LCD panel with lenticular lens array sheets. In case of a 2-view 3D, we attached the lens sheets, appropriate to a fine pitch LCD, in front of the panel. Throughout the advantage of high resolution, good 3D image quality was achieved with thinness and high brightness. for a multi-view 3D, due to its large view number, smooth motion parallax and low visual fatigue are observed. From the results, we believe that the VGA LCDs with lenticular lens sheets are suitable for the application of the mobile 3D displays.

Response time characteristics of optical shutter of vertical alignment liquid crystal cell for obliquely incident light

The temporal transmittance of a liquid crystal (LC) cell shutter was investigated for various incident angles to verify the possibility of a fast switching time. For a mono-domain vertical alignment (VA) cell, the switch OFF time in which the LC restores to its initial alignment state under no driving voltage is found to relate to the angle of the incident light. A decrease of switch OFF time is observed when the azimuth angle of the incident light approaches the azimuth angle of the LC optical axis. For a 4-domain VA cell, switch OFF time is observed not to decrease for any obliquely incident angle.

Determination of luminance distribution of autostereoscopic 3D displays through calculation of angular profile

— The luminance distribution of autostereoscopic 3-D displays using the parallax-barrier method was simulated by two different calculation methods. The first method directly calculates the total luminance distribution by summing light rays coming from different positions on the imaging display through a parallax barrier at each eye position. The second method first calculates the angular distribution of light rays coming from the imaging display through a parallax barrier and then derives the spatial luminance distribution for each eye position. The two methods resulted in an equivalent distribution. Yet, the second method outperforms the first method in terms of calculating the speed and versatility.

Evaluation method of electro-optical transfer function for display devices

— Various gamma-evaluation methods are investigated and newly suggested in order to establish a standard gamma metrology. First, test patterns are suggested and compared for display technologies that dynamically adjust gray levels such as global-dimming LCDs and PDPs. Second, two gamma-determination methods are compared and their accuracy determination methods are suggested. Third, two new models for gamma-distortion phenomena are suggested. Finally, the monotonic characteristics of EOTF are investigated. For the most part of this study, a new international standard named ICDM-DMS is suggested.

Moving-picture response time (MPRT) of LCDs for the oblique viewing direction

Abstract— The dynamic performance of displays is an important characteristic for multimedia applications. Motion-picture response time (MPRT) has been used as an indicator of the dynamic performance of LCDs. This paper describes a comprehensive method of MPRT evaluation for the oblique viewing direction. By using a tilted camera configuration, the angular dependency of MPRT is investigated for the condition that the horizontally scrolling patterns are observed from the vertical direction. For each gray-to-gray transition, distinct changes in MPRT and the luminance profile of blur are observed.