• Current Optics and Photonics
• /
• v.6 no.2
• /
• pp.171-182
• /
• 2022

A single-photon laser and mid-wave infrared (MWIR) common aperture optical system was designed and developed to detect and range a long-distance civil aviation aircraft. The secondary mirror of the Ritchey-Chretien (R-C) optical system was chosen as a dichroic lens to realize the design of a common aperture system for the laser and MWIR. Point spread function (PSF) ellipticity was introduced to evaluate the coupling efficiency of the laser receiving system. A small aperture stop and narrow filter were set in the secondary image plane and an afocal light path of the laser system, respectively, and the stray light suppression ability of the small aperture stop was verified by modeling and simulation. With high-precision manufacturing technology by single point diamond turning (SPDT) and a high-efficiency dichroic coating, the laser/MWIR common aperture optical system with a 𝜑300 mm aluminum alloy mirror obtained images of buildings at a distance of 5 km with great quality. A civil aviation aircraft detection experiment was conducted. The results show that the common aperture system could detect and track long-distance civil aviation aircraft effectively, and the coverage was more than 450 km (signal-to-noise ratio = 6.3). It satisfied the application requirements for earlier warning and ranging of long-range targets in the area of aviation, aerospace and ground detection systems.

• ETRI Journal
• /
• v.24 no.6
• /
• pp.429-434
• /
• 2002

This paper investigates the effect of a corrugated aperture on a common-mode current traveling along a penetrating wire. Computational results illustrate that the corrugated aperture acts as a filter, significantly reducing the common-mode current on the wire. This effect causes a reduction of radiated emission from cables passing through apertures on shielding enclosures. To predict and analyze the characteristics of the common-mode current on a straight wire passing through a corrugated aperture with cylindrical symmetry, the finite-difference time-domain (FDTD) method is applied.

• Journal of Information Display
• /
• v.2 no.1
• /
• pp.43-46
• /
• 2001

To meet the demand of the display market for large, flat, high-resolution screen, the Super Common eXtended field Oval lens (S-CXO) has been developed with resolution improvement of 10% or more compared to a conventional electron gun. A new main lens structure is adopted, to enhance the effectiveness of aperture and the performance. The new main lens can be assembled using an existing assembly system

• 제어로봇시스템학회:학술대회논문집
• /
• 2003.10a
• /
• pp.1664-1667
• /
• 2003

Aperture-coupled microstrip antenna is one type of microstrip antennas. This type of antenna has bandwidth wider than simple microstrip antenna. Herein, we use two substrates, that have the same dielectric constant 2.47 (PTFE-quartz) in which upper substrate is a rectangular patch. The microstrip patch is fed by a microstrip line which is printed on lower substrate, through an aperture or slot in the common ground plane of patch and microstrip feed. This antenna is analyzed by using Finite Difference Time Domain (FDTD) method the specific design frequency 10 GHz and match impedance is 50 ohms. The simulation results of its characteristics are input impedance, return loss, VSWR and radiation patterns respectively.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.290-293
• /
• 2006

We designed the H-IPS that has similar aperture ratio to the AS-IPS with organic insulator. To improve the aperture ratio without organic insulator, we positioned the pixel electrode over the preceding gate on the base of the H-IPS structure, and minimized the width of pixel and common electrodes. Without the additional process, we could obtain the similar brightness with that of AS-IPS in 15inch SXGA+ Panel.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2010.06a
• /
• pp.173-173
• /
• 2010

We proposed viewing angle switchable liquid crystal display(LCD) associated with fringe-field switching (FFS) mode with high aperture ratio characteristic. In the device, single pixel is separated into two regions, named as main pixel for displaying images and sub pixel for viewing angle control. In sub pixel region, add the common electrode on the top substrate and the initial alignment of liquid crystal is Hybrid Alignment Nematic (HAN) state. In conclusion, we suggested that the device has high aperture ratio characteristic because the LC directors are rotated in which viewing angle control region are generated fringe electric field.

• Current Optics and Photonics
• /
• v.2 no.3
• /
• pp.241-249
• /
• 2018

We report a midinfrared dual-field-of-view (FOV) optical system design for an airborne electro-optical targeting system. To achieve miniaturization and weight reduction of the system, it has a common aperture and fore-optics for three different spectral wavelength bands: an electro-optic (EO) band ($0.6{\sim}0.9{\mu}m$), a midinfrared (IR) band ($3.6{\sim}4.9{\mu}m$), and a designation laser wavelength ($1.064{\mu}m$). It is free to steer the line of sight by rotating the pitch and roll axes. Our design co-aligns the roll axis, and the line of sight therefore has a fixed entrance pupil position for all optical paths, unlike previously reported dual-FOV designs, which dispenses with image coregistration that is otherwise required. The fore-optics is essentially an achromatized, collimated beam reducer for all bands. Following the fore-optics, the bands are split into the dual-FOV IR path and the EO/laser path by a beam splitter. The subsequent dual-FOV IR path design consists of a zoom lens group and a relay lens group. The IR path with the fore-optics provides two stepwise FOVs ($1.50^{\circ}{\times}1.20^{\circ}$ to $5.40^{\circ}{\times}4.32^{\circ}$), due to the insertion of two Si lenses into the zoom lens group. The IR optical system is designed in such a way that the location and f-number (f/5.3) of the cold stop internally provided by the IR detector are maintained when changing the zoom. The design also satisfies several important performance requirements, including an on-axis modulation transfer function (MTF) that exceeds 10% at the Nyquist frequency of the IR detector pitch, with distortion of less than 2%.

• Journal of Korea Society of Industrial Information Systems
• /
• v.6 no.4
• /
• pp.6-11
• /
• 2001

In this paper, the aperture-coupled U-slot microstrip patch antenna is studied for the bandwidth improvement. The aperture is used as a mechanism for coupling the radiating element to the microstrip feedline, and the aperture-coupled configuration provides the advantage of isolating spurious feed radiation by the use of common ground plane. Experimental results such as return loss, VSWR, radiation pattern and gain measurements are presented on the aperture-coupled U-slot microstrip patch antenna. The impedance bandwidth (VSWR≤2) of the antenna is 6.4% centered at 2.35GHz, and the average gain is 5.3 dBi.

• Current Optics and Photonics
• /
• v.8 no.5
• /
• pp.484-492
• /
• 2024

In response to the difficulty of synchronously obtaining multiwavelength images for fast two-dimensional (2D) temperature measurement, a multispectral framing imaging optical system is designed, based on the segmented-aperture imaging method and asymmetric surface shape. The system adopts a common-aperture four-channel array structure to synchronously collect multiwavelength temperature-field images. To solve the problem of asymmetric aberration caused by being off-axis, a model of the relationship between incident and outgoing rays is established to calculate the asymmetric custom surface. The designed focal length of the optical system is 80 mm, the F-number is 1:3.8, and the operating wavelength range is 0.48-0.65 ㎛. The system is divided into four channels, corresponding to wavelengths of 0.48, 0.55, 0.58, and 0.65 ㎛ respectively. The modulation transfer function value of a single channel lens is higher than 0.6 in the full field of view at 35 lp/mm. The experimental results show that the asymmetric-custom-surface imaging system can capture clear multiwavelength images of a temperature field. The framing imaging system can capture clear images of multiwavelength temperature fields, with high consistency in images of different wavelengths. The designed optical system can provide reliable multiwavelength image data for 2D temperature-field measurement.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2006.11a
• /
• pp.43-44
• /
• 2006

We have studied electro-optical characteristics and stability of liquid crystal director depending on electrode patterning of common electrode on top substrate in patterned vertical alignment (PVA) mode. In the present studies, new type of common electrode pattern was suggested to enhance a dark state by reducing interference area due to data signal. According to the simulation result, PVA device with new common electrode pattern contributed to Improvement of an aperture ratio.