• Journal of the Ergonomics Society of Korea
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• v.33 no.3
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• pp.191-202
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• 2014

Objective: This study is conducted on the differences between flat and curved displays with respect to location of focused points, posture and satisfaction as well as preferred tilt angles. Background: In order to avoid physical and eye fatigue caused by misplayed sitting posture, many studies have asserted that the display requires appropriate location, size and tilt angle as well as curvature. However, most studies have focused on the work environment and the results are varied in the extent. Method: Eye height data in sitting posture were collected from 30 participants. Participants selected the most comfortable viewing angle within the range from $0^{\circ}$ to $12^{\circ}$ while watching videos for both curved and flat display. Then, physical and eye fatigue and overall satisfaction were subjectively evaluated. Lateral diagram describing viewing display condition was set and used to develop linear models for expecting the preferred tilt angle. Results: Due to sitting in the natural viewing posture rather than upright, the eye height is lowered to about 4.6 centimeters, on average, for both displays showing no significant differences. In contrast, preferred angles for the two displays are significantly different and this can be interpreted that curvature vary the points focused. Two linear models as functions of sitting eye height are developed to expect preferred tilt angle for each display. Based on the result of overall satisfaction evaluation, curved display is statistically better than flat display. Conclusion: The results show that flat and curved displays are significantly different expect for the viewing posture. However, reasons for preferring curved display are not accurately factorized and the linear models are limited in the experiment condition such as size of display, distance between display and viewer and other physical environmental factors. Further studies on curved displays under more various conditions are required. Application: This study can contribute to use of the curved display in various way.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.119-123
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• 2023

This study is normal orientation technology of slit coating equipment to improve the quality of curved displays. Currently, the demand for curved displays is increasing significantly due to advantages such as screen immersion or design in various industries. Accordingly, changes in the display coating process are essential. In the curved display coating process, unlike the existing flat coating process, the nozzle must be rotated along the curvature of the curved surface to spray the coating solution. The coating solution must be applied while maintaining a uniform thickness. If the thickness of the coating liquid applied to the target surface is non-uniform, the quality of the product may be degraded such as image quality deterioration and light spreading. This paper presents technology and experimental results for keeping the nozzle of slit coating equipment perpendicular to the curved surface and is expected to contribute to the quality improvement of curved displays.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1087-1090
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• 2008

This paper presents the electro-luminescence (EL) display lamp which is patterned on a curved surface by the pad printing method. The printing methods, including the gravure, screen, flexo, inkjet, and pad printing, have an advantage of one-step direct patterning. However, in general, the printing and semi-conductor process, except pad printing method, cannot be applied for patterning on a curved surface. Thus, in this paper, we used pad printing method for patterning an EL display lamp on a curved surface. The EL display lamp consists of 5 layers: Bottom electrode; Dielectric layer; Phosphor; Transparent electrode; Bus electrode. Finally, we printed EL display lamp on a dish, which has a radius of curvature 80mm. The EL display lamp was driven at AC 200V of 1kHz.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1595-1598
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• 2005

Integral imaging attracts much attention as an autostereoscopic three-dimensional (3D) display technique for its many advantages. Recently the method that uses a curved lens array with a curved screen has been reported to overcome the limitation of viewing angle in integral imaging. This method widens the viewing angle remarkably. However, to understand the proposed system we need to know how the depth is limited in the proposed method also. We analyze the depth limitation and show the simulation results.

• Journal of the Semiconductor & Display Technology
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• v.20 no.2
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• pp.51-55
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• 2021

With the recent development of various smartphone designs in the smartphone market, the use of curved cover glass has been required, and interest in curved glass production has increased. In this paper, we designed a pressurization system that simplified the size of the system using a wedge amplification mechanism for smartphone curved glass molding systems. The pressurization system consisted of a linear motor, a wedge, and a force sensor. The wedge was used to amplify the force, and the piezoelectric sensor was used to measure the force. In addition, the proposed amplification mechanism was confirmed to have an error of 1.27% through an experiment compared to the simulation, and the pressurization error of 0.76% for the pressurization profile 3,500N was verified through an experiment.

• Journal of Information Display
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• v.7 no.4
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• pp.1-4
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• 2006

The optical performances of rounded prism films were investigated using a ray tracing technique. The angular distribution of the luminous intensity was obtained as functions of the prism pitch and the curvature of rounded apex and valley of prism arrays. The gain of the on-axis luminance decreased with decreasing curvature (increasing diameter) and pitch. The existence of the curved area on the prism film decreased the recycling efficiency of the prism film, i.e., the rays which would otherwise have been recycled through total internal reflections via the prism surfaces were refracted on the curved regions and redirected toward directions other than the on-axis direction. Quantitative correlation between the luminance gain and the curvature in addition to the prism pitch was obtained, which might serve as basic data for the optimization of prism films and the manufacturing processes.

• Steel and Composite Structures
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• v.35 no.4
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• pp.567-578
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• 2020

Based on third-order shear deformation shell theory, the present paper investigates post-buckling properties of eccentrically stiffened metal foam curved shells/panels having initial geometric imperfectness. Metal foam is considered as porous material with uniform and non-uniform models. The single-curve porous shell is subjected to in-plane compressive loads leading to post-critical stability in nonlinear regime. Via an analytical trend and employing Airy stress function, the nonlinear governing equations have been solved for calculating the post-buckling loads of stiffened geometrically imperfect metal foam curved shell. New findings display the emphasis of porosity distributions, geometrical imperfectness, foundation factors, stiffeners and geometrical parameters on post-buckling properties of porous curved shells/panels.

• Journal of the HCI Society of Korea
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• v.10 no.2
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• pp.13-19
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• 2015

Display technology has recently made enormous progress. In particular, display companies are competing each other to develop flexible display. Curved display, as a precursor of flexible display, are now used for smart phones and TVs. Curved monitors have been just introduced in the market, and are used for office work or entertainment. The aim of the current study was to investigate whether the curvature of a 42" multi-monitor affects postural control when it is used for entertainment purpose. The current study used two curvature levels (flat and 600mm). Ten college students [mean(SD) age = 20.9 (1.5)] with at least 20/25 visual acuity, and without color blindness and musculoskeletal disorders participated in this study. In a typical VDT environment, each participant played a car racing video game using a steering wheel and pedals for 30 minutes at each curvature level. During the video game, a pressure mat on the seat pan measured the participant's COP (Center of Pressure), and from which four measures (Mean Velocity, Median Power Frequency, Root-Mean-Square Distance, and 95% Confidence Ellipse Area) were derived. A larger AP (Anterior-Posterior) RMS distance was observed in the flat condition, indicating more forward-backward upper body movements. It can be partly due to more variability in visual distance across display, and hence longer ocular accommodation time in the case of the flat display. In addition, a different level of presence or attention between two curvature conditions can lead to such a difference. Any potential effect of such a behavioral change by display curvature on musculoskeletal disorders should be further investigated.

• Journal of Information Display
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• v.4 no.1
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• pp.38-42
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• 2003

CRTs can survive in the long run for TV applications, because of their realistic reproduction of live images. CRT technology development has to be directed towards form factor, but also attention has to be paid to the form design of sets. The CRT is the only technology allowing a doubly curved screen surface.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.8
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• pp.794-800
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• 2015

This paper describes the design for a defective product inspection device for the curved glass used in smart-phone. Cameras are used as inspection devices to find cracks in LCDs (Liquid Crystal Displays), PDPs (Plasma Display Panels), etc. The devices used to inspect the curved glass used in smart-phone consist of a camera, two back-light apparatus, an inspection apparatus main body, and an image processing program. Camera image calibration was performed to smooth an image taken with the camera, and as a result, the average error was less than 0.12 pixels. And the image of a smart-phone's curved glass taken with the camera was processed using the produced program. As a result, the program could correctly extract the cracks on the curved glass. Thus, it is thought that the designed inspection device can successful detect cracks in curved tempered glass.