• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1749-1752
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• 2007

The Near to Eye Display (NED) solves the problem of having a display larger than a small portable device. The virtual image of the NED is created using a microdisplay and imaging optics. It is important that the optics does not interfere with the human visual system and that the device is light, compact and easy to wear. In this paper the principles of a biocular NED, which is based on a novel diffractive Exit Pupil Expander (EPE), are presented. The optical system is compact and intrinsically free from distortions and misalignments.

• Current Optics and Photonics
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• v.4 no.6
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• pp.524-529
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• 2020

We propose a depth-fused-type three-dimensional (3D) near-eye display implemented using a birefringent lens set that is made of calcite. By using a birefringent lens and image source (28.70 mm × 21.52 mm), which has different focal lengths according to the polarization state of the incident light, the proposed system can present depth-fused three-dimensional images at 4.6 degrees of field of view (FOV) within 1.6 Diopter (D) to 0.4 D, depending on the polarization distributed depth map. The proposed method can be applied to near-eye displays like head-mounted display systems, for a more natural 3D image without vergence-accommodation conflict.

• Current Optics and Photonics
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• v.4 no.2
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• pp.121-126
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• 2020

With the increasing demand for head-mounted display applications, the image quality provided by a near-eye display device is a key factor in satisfying the consumer. Among various techniques to realize a near-eye display that has a thinner volume than the working distance of a human eye, a lightfield image-generation method based on a pinhole array is attracting much attention, with its simple and thin structure. In this paper, we propose a numerical analysis of the visual parameters and verifications with computational reconstruction.

• Journal of Information Display
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• v.13 no.2
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• pp.67-71
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• 2012

In today's mobile world, small and lightweight information systems are becoming increasingly important. Microdisplays are the base for several near-to-eye display devices. The addition of an integrated image sensor significantly boosts the range of applications. This paper describes the base-building block for these systems: the bidirectional organic light-emitting diode microdisplay. A small and lightweight optic design, an eye-tracking algorithm, and interaction concepts are also presented.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.37-43
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• 2013

Purpose: The present study was conducted to investigate whether the directions of eye movement in playing computer games for certain period affected the change of near point of convergence (NPC) and fusional reserve (FR) or not. Methods: Total 40 subjects in 20s who have the visual acuity of 1.0 or higher without any ocular disease and accommodative dysfunction were asked to successively play computer games. After the subjects were moving eyes in horizontal and vertical directions for 40 and 90 minutes, their horizontal fusional reserves, vertical fusional vergence and near point of convergence were measured. Results: The near point of convergence showed a tendency to be receded after computer gaming in the horizontal and vertical directions, and both of horizontal and vertical fusional reserves were significantly reduced. The range of declined fusional reserves and receded near point of convergence after computer gaming for 90 minutes was smaller than those after computer gaming for 40 minutes. The change of binocular vision was affected by the horizontal eye movement rather than the vertical movement when analyzed by the direction of eye movement. Conclusions: This study revealed that the change in FR and NPC was different along with dominant direction of eye movement during visual display terminal (VDT) tasks. Therefore, the adjustment of VDT working time is required to prevent the dysfunction of binocular vision according to the dominant direction of eye movement during VDT task.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.17-26
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• 2006

Video display units (VDU) are interfaces between computers and human operators. This study was performed to have a good understanding of the potential causes of eye problems in 50 students to enable them to perform an accurate assessment of the patient's visual performance while looking at a computer screen. The TSS Optometric Toolkit for Computer Users provides a powerful set of tools to enable eye care practitioners to assess visual performance under conditions that closely simulate a computer user's normal working conditions. The program consists of seven tests: Near vision chart, Sample text display, Spreadsheet display, Fixation disparity, Duochrome, Number search, Randolt Ring search. The results of this study show that 55% of the subjects do not have computer-related eye problems. It is apparent from this data that approximately 25% of all computer-related eye problems are attributable to the display screen, the workstation or inappropriate workpractices. Of the remaining cases, 20% of them will require general purpose spectacles and spectacles specifically for work at the computer. This study suggests that computer program, The TSS Optometric Toolkit for Computer Users, is very useful for assessment of computer-related eye problems.

• Journal of Digital Convergence
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• v.16 no.10
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• pp.531-536
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• 2018

The purpose of this study is to investigate eye fatigue and analyze symptoms of visual discomfort according to near work in young adults. A survey was conducted on 347 young adults aged 25.37 years (142 male and 205 female participants). The eye fatigue using Conlon questionnaire were surveyed and near work was investigated amounts of daily computer and smartphone. The score of eye fatigue was $13.65{\pm}7.11$ in less than 2 h/d, $16.83{\pm}6.77$ in 2~4 h/d, $18.88{\pm}6.60$ in 4~6 h/d, and $18.83{\pm}5.62$ in more than 6 hours(p=0.001). Also, headache(p<0.030), re-reading(p<0.036), and movement and fading(p<0.001) symptoms increased according to amounts of near work.

• ETRI Journal
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• v.45 no.6
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• pp.1046-1055
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• 2023

We introduce a display for virtual-reality (VR) fire training. Firefighters prefer to wear and operate a real breathing apparatus while experiencing full visual immersion in a VR fire space. Thus, we used a thin head-mounted display (HMD) with a light field and folded optical system, aiming to both minimize the volume for integration in front of the face into a breathing apparatus and maintain adequate visibility, including a wide viewing angle and resolution similar to that of commercial displays. We developed the optical system testing modules and prototypes of the integrated breathing apparatus. Through iterative testing, the thickness of the output optical module in front of the eyes was reduced from 50 mm to 60 mm to less than 20 mm while maintaining a viewing angle of 103°. In addition, the resolution and image quality degradation of the light field in the display was mitigated. Hence, we obtained a display with a structure consistent with the needs of firefighters in the field. In future work, we will conduct user evaluation regarding fire scene reproducibility by combining immersive VR fire training and real firefighting equipment.

• Journal of the Semiconductor & Display Technology
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• v.21 no.3
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• pp.92-97
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• 2022

Plastics are classified into 7 types such as PET (PETE), HDPE, PVC, LDPE, PP, PS, and Other for separation and recycling. Recently, large corporations advocating ESG management are replacing them with bioplastics. Incineration and landfill of disposal of plastic waste are responsible for air pollution and destruction of the ecosystem. Because it is not easy to accurately classify plastic materials with the naked eye, automated system-based screening studies using various sensor technologies and AI-based software technologies have been conducted. In this paper, NIR scanning devices considering the NIR wavelength characteristics that appear differently for each plastic material and a system that can identify the type of plastic by learning the NIR spectrum data collected through it. The accuracy of plastic material identification was evaluated through a decision tree-based SVM model for multiclass classification on NIR spectral datasets for 8 types of plastic samples including biodegradable plastic.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.939-942
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• 2004

In this study, we report simulation results of single-panel LCOS (liquid crystal on silicon). Reflective LCOS microdisplays are widely used in various projection and near-eye application. For one panel system, liquid crystal response time is an important variable. The panel must switch fast enough to support the display of Field color sequential with high field rates. In order to have fast response and good contrast, a vertical alignment (VA) cell was used in this study. With suitable selection on LC parameters like temperature, viscosity, elastic constant and birefringence, it is possible to get response time of around 2ms from a 2.0 um-thick vertical alignment cell. This result also indicates an ease of production control on 2.0 um cells than 1.0 um cells.