• Journal of the Optical Society of Korea
• /
• v.16 no.4
• /
• pp.365-371
• /
• 2012

A three-dimensional integral-floating display with 360 degree horizontal viewing angle is proposed. A lens array integrates two-dimensional elemental images projected by a digital micro-mirror device, reconstructing three-dimensional images. The three-dimensional images are then relayed to a mirror via double floating lenses. The mirror rotates in synchronization with the digital micro-mirror device to direct the relayed three-dimensional images to corresponding horizontal directions. By combining integral imaging and the rotating mirror scheme, the proposed method displays full-parallax three-dimensional images with 360 degree horizontal viewing angle.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.7
• /
• pp.106-115
• /
• 2002

Growth characteristics of micro carbon structures fabricated by laser-assisted chemical vapor deposition are studied. Argon ion laser and ethylene were used as the energy source and reaction gas, respectively, to grow micro carbon rod through pyrolytic decomposition of the reaction gas. Experiments were performed at various conditions to investigate the influence of process parameters on growth characteristics such as the diameter or growth rate of the micro carbon rod with respect to reaction gas pressure and incident laser power. Reaction gas pressure in experiments ranges from 200 to 600Torr and the incident laser power from 0.3 to 3.8W. For these conditions, the diameter of the rod increases linearly with respect to the laser power but is almost independent of the reaction gas pressure. Growth rate of the rod changes little with gas pressure when the laser power remains below IW. For a constant reaction gas pressure, the growth rate increase with Increasing laser power, but the rate of increase decreases gradually, implying that the chemical vapor deposition condition changes from a kinetically-limited regime to a mass-transport-limited regime. When the carbon rod was grown at near threshold laser power, a very smooth surface is obtained on the rod. By continuously moving the focusing lens in the direction of growth, a micro carbon rod with a diameter of 287${\mu}{\textrm}{m}$ and aspect ratio of 100 was fabricated..

• Journal of the Semiconductor & Display Technology
• /
• v.21 no.1
• /
• pp.95-102
• /
• 2022

Since the organic light-emitting diodes (OLEDs) have been widely investigated as next-generation displays, it has been successfully commercialized as a flexible and rollable display. However, there is still wide room and demand to improve the device characteristics such as power efficiency and lifetime. To solve this issue, there has been a wide research effort, and among them, the internal and the external light extraction techniques have been attracted in this research field by its fascinating characteristic of material independence. In this study, a micro-nano composite structured external light extraction layer was demonstrated. A reactive ion etching (RIE) process was performed on the surfaces of hexagonally packed hemisphere micro-lens array (MLA) and randomly distributed sphere diffusing films to form micro-nano composite structures. Random nanostructures of different sizes were fabricated by controlling the processing time of the O₂ / CHF₃ plasma. The fabricated device using a micro-nano composite external light extraction layer showed 1.38X improved external quantum efficiency compared to the reference device. The results prove that the external light extraction efficiency is improved by applying the micro-nano composite structure on conventional MLA fabricated through a simple process.

• Laser Solutions
• /
• v.12 no.3
• /
• pp.1-6
• /
• 2009

This paper describes the method for the fabrication of micro dot array on a plastic mold steel using DPSS (diode pumped solid-states) UV laser and wet etching process. We suggest the process of the ablation of a photoresist (PR) coated on plastic mold steel and wet etching process using solutions of various concentrations of $FeCl_3$, $HNO_3$ in water as etchant. This method makes it possible to fabricate metallic roller mold because the microstructures are directly fabricated on the metal surface. In the range of operating conditions studied, $17\;{\mu}J$ laser pulse energy and 50 ms laser exposure time, an etchant containing 40wt% $FeCl_3$, 5wt% $HNO_3$ and etch time for 45 s gave the $10\;{\mu}m$ of micro dot pattern on plastic mold steel.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.380-381
• /
• 2012

Bioinspired sea urchin-like structures were fabricated on silicon by inductively coupled plasma (ICP) etching using lens-like shape hexagonally patterned photoresist (PR) patterns and subsequent metal-assisted chemical etching (MaCE) [1]. The lens-like shape PR patterns with a diameter of 2 ${\mu}m$ were formed by conventional lithography method followed by thermal reflow process of PR patterns on a hotplate at $170^{\circ}C$ for 40 s. ICP etching process was carried out in an SF6 plasma ambient using an optimum etching conditions such as radio-frequency power of 50 W, ICP power of 25 W, SF6 flow rate of 30 sccm, process pressure of 10 mTorr, and etching time of 150 s in order to produce micron structure with tapered etch profile. 15 nm thick Ag film was evaporated on the samples using e-beam evaporator with a deposition rate of 0.05 nm/s. To form Ag nanoparticles (NPs), the samples were thermally treated (thermally dewetted) in a rapid thermal annealing system at $500^{\circ}C$ for 1 min in a nitrogen environment. The Ag thickness and thermal dewetting conditions were carefully chosen to obtain isolated Ag NPs. To fabricate needle-like nanostructures on both the micron structure (i.e., sea urchin-like structures) and flat surface of silicon, MaCE process, which is based on the strong catalytic activity of metal, was performed in a chemical etchant (HNO3: HF: H2O = 4: 1: 20) using Ag NPs at room temperature for 1 min. Finally, the residual Ag NPs were removed by immersion in a HNO3 solution. The fabricated structures after each process steps are shown in figure 1. It is well-known that the hierarchical micro- and nanostructures have efficient light harvesting properties [2-3]. Therefore, this fabrication technique for production of sea urchin-like structures is applicable to improve the performance of light harvesting devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2003.04a
• /
• pp.193-197
• /
• 2003

As one of the core technologies in the field of the optical communication with WDM, the optical cross connector with movements of micro mirrors is getting important day by day. The packaging structure of 2-dimensional NxN MOEMS switch should be determined by the harmonization of the following items such as the geometrical compatability between optical and structural components, the characteristics of optical input and output parts with device, and the electrical performance for the operation of micro mirrors. Therefore, the packaging process could be defined as the integrated technology completed by the optical and electrical science and the material science for the understanding of its thermo-mechanical properties with packaging materials. In the present study, the harmonization between the optical and structural components as well as the optical characteristics of lens system used will be investigated.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.53 no.2
• /
• pp.109-116
• /
• 2016

Sensing module of standing and moving human body using shutter method was developed. The module consists of Fresnel lens, pyroelectric infrared (PIR) sensor, interface circuit of the PIR, micro control unit(MCU), and alarm light emitting diode(LED). The principle for standing human body is chopping the thermal of human body using camera shutter. The human sensing signal in MCU by algorithm of interrupt function is detected. By unifying an apparatus and print circuit board(PCB), the developed module can be replaced as commercial moving human body detector. Experiment results show that sensing distance is about 7.0m and sensing angles is about $110^{\circ}$ at room temperature. In these condition, sending ratio was 100% and the power dissipation of the module was 100mW.

• Korean Journal of Optics and Photonics
• /
• v.14 no.3
• /
• pp.306-311
• /
• 2003

In this paper, we modeled the incident beam in order to analyze and evaluate the optical thin film device for wavelength division multiplexing in optical telecommunication network. As applied ray tracing method to the optical path, we were compared the accuracy of coupling efficiency simulated by two modeling methods. In the results of sinulation, ceil modeling method was preferred to annual modeling method in micro-optic device because of accuracy for coupling efficiency and Gaussian intensity distribution. In the results of optimal simulation for optical device using thin film filter, the distance (d1) between optical fiber and GRIN lens, the distance (d2) between GRIN lens and thin film filter and the coupling efficiency were 0.24 mm, 0.25 mm and -0.11 ㏈ respectively. As d2 was displaced at 0.25 mm and d1 was varied in order to evaluate the optimal value, d1 and maximum coupling efficiency were 0.24 mm and -0.35㏈, respectively. Then the results of experiment were corresponded to that of optimal simulation by cell modeling and it was possible to analyze the performance for optical device using thin film filter by the simulation.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.9
• /
• pp.6227-6235
• /
• 2015

The HUD has recently been downsized due to the development of micro display and LED technology as a see through information display device, gradually expands the application areas. In this paper, using a DLP micro display device designed a compact head-up display(HUD) optical system for biocular observation of the image exhibition area 5 inches. It was analyzed for each design element of the optical system in order to design a compacted HUD. DLP, projection optical system and concave image combiner were discussed the design approach and the characteristics. Through a connection structure analysis of each optical system, detailed design specifications were set up and designed the optical system in detail. Put a folded configuration in the form of a white diffuse reflector between the projection lens and concave image combiner was designed to be independent, respectively. Distance of the projected image is adjustable up to approximately 2m ~ infinity and observation distance is 1m. Resolution could be recognized by 1 ~ 2pixels in HD($1,280{\times}720pixels$) class, various characters and symbols could be read. In addition, color navigation map, daytime video camera and thermal imaging cameras can be displayed.

• Journal of electromagnetic engineering and science
• /
• v.10 no.3
• /
• pp.132-137
• /
• 2010

We present results of room-temperature characterization of lithographically manufactured antenna-coupled NbN micro-bolometers. The bolometers are assembled together with a hyper-hemispherical Si lens to couple the incident radiation to the bolometer from the back-side of the substrate. The bolometers are designed to operate at 300~1,000 GHz and they are characterized at 321~782 GHz. Radiation patterns are measured at 321 GHz, 400 GHz, 654 GHz, and at 782 GHz. The frequency dependency of the beamwidth is studied with several azimuthal beam profile measurements at 321~500 GHz.