• Journal of the Optical Society of Korea
• /
• v.19 no.6
• /
• pp.614-618
• /
• 2015

This paper described an off-axis head-mounted display system. It is composed of a 7-piece coaxial relay lens group and a freeform surface combiner. This configuration has a simple structure and a wide field of view (FOV). In this design, a freeform surface is chosen as the combiner, to simplify the structure and attain good image quality. We generated this freeform surface by considering both coordinates and normals of discrete data points. Moreover, we realize a coaxial structure in the relay lens group, which is compact and benefits from a loose tolerance requirement. The HMD system we finally realized has a 40° × 30° FOV and 15-mm exit pupil diameter.

• Journal of Ceramic Processing Research
• /
• v.13 no.spc2
• /
• pp.363-367
• /
• 2012

DLC (diamond liked carbon) coating of the tungsten carbide (WC) alloy core surface for molding a glass aspheric lens improves the quality of glass lens and the molding core and is characterized by high hardness, high elasticity, abrasion resistance and chemical stability. In this study, the effect of DLC coating of a thin film by means of the filtered AIP (arc ion plating) technique was examined on Ra and shape of the coated surface. Roughness before and after DLC coating was measured and the result showed that the roughness was improved after coating as compared to before coating. It was observed that DLC coating of the WC alloy core surface for molding had an effect on improving the roughness and shape of the core surface. It is considered that this will have an effect on improving abrasion resistance and the service life of the core surface.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2012.10a
• /
• pp.347-348
• /
• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2013.05a
• /
• pp.661-662
• /
• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2008.06a
• /
• pp.377-378
• /
• 2008

• Korean Journal of Optics and Photonics
• /
• v.11 no.4
• /
• pp.246-249
• /
• 2000

The null lens is designed for testing the elliptical (conic constant>O) mirror which is the third mirror of the off-axis Three Mirror Anastigmat (TMA) designed as a high resolution camera for remote sensing. The mixed type design is proposed as a new design type which has a small annular flat mirror, but has as twice sensitivity as the autostigmatic type design. It is also shown that the null lens of the Mixed type is better than that of the autostigmatic type in terms of the sensitivity of the wavefront distortion which is given as the magnitude of optical path difference with respect to the change of each surface parameters such as the radius of curvature, thickness of lenses and tested mirror.

• The Transactions of the Korean Institute of Electrical Engineers D
• /
• v.55 no.12
• /
• pp.547-549
• /
• 2006

We have proposed a novel algorithm for detecting scan alluk on the surface of a TFT-LCD device that is generated by non-uniform exposure during fabrication. The scan alluk is known to have similar intensity values on paths that are determined by the shape of lens for light exposure. Based on the observation, the proposed algorithm inspects the uniformity on the paths using 1D projection image of 2D LCD image and 2D backprojection image of the 1D image. We have shown the usefullness of the proposed method by theoretical analysis and experimental results.

• Journal of the Korean Institute of Telematics and Electronics D
• /
• v.34D no.9
• /
• pp.64-71
• /
• 1997

A new etching technique of meltback was investigated for GaAs lensed optical devices with selective windows opending in the LPE (liquid phase epitaxy) system. In the meltback process, the etch depth and the etch shape were controlled by the degree of under-saturation, etch time and other parameters. A GaAs/AlGaAs DH layer was grown on the selectively etched hemispherical well for optical device application such as lensed surface emitting LED. The regrowth process were related with the coolin grate and the well to well spacing. A novel surface emitting LED with hemispherical AlGaAs lens was fabricated using the meltbakc and regrowth as the key process for AlaAs lens array. The light emitting efficiency of the LED was upto three times higher than the similar structure LED without lens. The meltback and regrowth technique was applicable to manufacture the optical device in LPE.

• Journal of Korean Ophthalmic Optics Society
• /
• v.11 no.2
• /
• pp.115-119
• /
• 2006

Electromagnetic shielding, transparent ITO coating layers have deposited on ocular lens substrate by magnetron sputtering. We investigated the effect induced by the substrate temperature on coating layer. The characteristics of the coating layers were analyzed using surface profiler, four-point probe, XRD, spectrophotometer and Auger Electron spectroscopy. As substrate temperature became higher, carrier concentration was increased and transmittance in the visible region was increased, too.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2008.06a
• /
• pp.452-452
• /
• 2008

Abstract Head-mounted displays(HMD) are being developed and marketed in growing numbers for a variety of applications. Though most commonly associated with entertainment applications other applications are also being developed. The field vision on the display screens is expanded by the optical system producing an imaginary screen that appears to be positioned several meters in front of the viewer. In this study, the mold core for the prism lens of HMD was processed by fly-cutting method, and the form accuracy of the mold core was measured.