• New Physics: Sae Mulli
• /
• v.68 no.11
• /
• pp.1268-1274
• /
• 2018

Aircraft-warning lights are lights that are used to inform pilots in flight about the presence of buildings or dangerous objects. Currently, the light sources of most aircraft-warning lights have been replaced by light-emitting diodes (LEDs). However, the aircraft-warning lights that are installed do not meet the optical performance standards and may cause airplane collisions. Therefore, the use of such light poses a risk to aviation safety. In order to solve this problem, we designed a Fresnel lens with the same luminous intensity distribution ovef $360^{\circ}$ direction; thus, we collimated the light beam from the LED light source with a narrow beam divergence angle in the form of an array of aspheric pieces. After that, we designed and simulated an aircraft-warning-light optical system with a center luminous intensity of 20,000 cd and a vertical divergence angle of $3^{\circ}$ or more by optimizing the lens' tilt and the distance between the LED and the Fresnel lens.

• Journal of Korean Ophthalmic Optics Society
• /
• v.17 no.2
• /
• pp.159-164
• /
• 2012

Purpose: Of the various methods of vision training, the essay aims to explore the effective ways of using the Fresnel prism lens in order to expand the positive fusional vergence for the patient having specific condition of convergence insufficiency or basic exophoria. Methods: 15 students of city of Daejeon university without an eye disease (average age $22.73{\pm}1.68$) were selected and underwent the subjective refraction test and binocular vision test, and recording their test results before vision training and replacing an identical frame with a lens of same quality after the full calibration, the lens was then adhered with the Fresnel prism lens and continued to train for thirty minutes daily during two weeks. Afterwards, the binocular vision test was reattempted. The observation of the change in the results of the binocular vision test in use of the fresnel prism lens in the vision training test was researched. Results: After training, the positive fusional vergence had increased to a number of $22.27{\pm}2.26$ $\Delta$, to 7.80 $\Delta$, at near, the fused cross cylinder test increased to an average of $0.55{\pm}0.09$ D, 0.40 D after training, showing a normal result. The value of negative relative accommodation after training had an average of $2.22{\pm}0.08$D, showing that 0.42 D had increased. The value of near point of convergence after training had an average of $6.13{\pm}0.53$ cm, showing that 2.80 cm had decreased. To patients who had convergence insufficiency or basic exophoria, the value of the near vision test that used the Fresnel prism lens which was able to expand BO positive fusional vergence had increased without phoria. Conclusions: The changes were tested and the effectiveness of the Fresnel prism lens, due to the nature of the lens itself, helped with both cosmetic effects and cost. It also allows good optical correction effects, in addition to these clinical effects indicated before. Therefore, it may be determined that the Fresnel prism lens binocular vision therapy for patients is more popular and highly recommended.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.15 no.6
• /
• pp.1221-1226
• /
• 2011

In order to analyze the receiver gain characteristic of the Soret-type FZPL lens antenna which is operated at 12GHz, TLM method can be applied. The application of the FZPL lens antenna is often use the receiver for satellite TV system, radio telescope, and Geodetic System. Some numerical results computed by TLM method are compared with Kirchhoff's approximation and PO method. The focal characteristic of receiver gain on main axis of the FZPL is mostly shown at the front side, which means that the position of the receiver should be properly calibrated.

• Proceedings of KOSOMES biannual meeting
• /
• 2005.11a
• /
• pp.65-69
• /
• 2005

The theoretical propagation modes of radio waves in the area of Line of Sight(LOS) within Fresnel zone are searched for the available detection ranges in a Marine RFID (Radio Frequency Identification). The structural LOS model to Earth's curvature is proposed and, the calculation method of horizontal distance in a specific radio frequency is also considered in this work As studying results, it is found that the height of antenna to cover the detection ranges and the influences of detection ranges by weather environments can be analyse with the theoretical methods.

• Geophysics and Geophysical Exploration
• /
• v.6 no.2
• /
• pp.101-107
• /
• 2003

3D seismic travel-time tomography algorithm baled on Fresnel volume was developed and its feasibility was investigated by the numerical experiments. To testify the field applicability of the developed algorithm, frequency characteristics and way coverage of the crossholel seismic raw data were investigated and 3D velocity tomogram cube with about 8m spatial resolution was obtained. When compared this 3D velocity cube with the conventional 2D ray tomogram, two results were matched well. We concluded that 3D seismic tomography algorithm developed in this study has enough potential to the field application.

• Korean Journal of Optics and Photonics
• /
• v.15 no.6
• /
• pp.511-518
• /
• 2004

Providing marine signal lanterns with advantages of little weight as well as large aperture, a Fresnel lens has been adopted to transfer the beam from the lanterns up to 10 nautical miles (18.53 km). A Fresnel lens with the diameter of 250 mm and 300 mm was designed by a lens design program and optimized by adjusting the groove parameters of the lens. The angular luminous intensity distribution (ALID) of this lens was calculated by using an illumination analysis program considering the ALID of a light bulb. At the best alignment of the bulb, the maximum luminous intensities (MLI) of the lantern were 1000 cd (in the case of 250 mm diameter) and 1300 cd (in the case of 300 mm diameter). These are more than the critical value of 720 cd that is the Korean Standard of MLI for the marine lantern. The ALID was investigated as a function of misalignment from the lens focus to determine the tolerance of the alignment ranges.

• Journal of Korea Game Society
• /
• v.16 no.1
• /
• pp.111-118
• /
• 2016

This paper proposes the mathematical model of Fresnel effect used to illuminate and simulate a surface character model for defense game play. The term illumination is used to represent the process by which the amount of light reaching a surface character model used on game play is determined. The character surface shaders generally use a mathematical model to predict how light will reflect on triangles. The shading normally represents the methods used to determine the color and intensity of light reflected toward the viewer for each pixel representing the character surface model of the game. This model computes the reflection and transmission coefficients and compares simulated results to the Fresnel equations for the real game improvement.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.05a
• /
• pp.74-76
• /
• 2012

In order to design Transceiver/Receiver antenna with high gain in Ka band, Fresnel zone plate lend(FZPL) antenna is considered and analyzed. Physical optics is applied to demonstrate the FZPL. The FZPL is configured to 11 elements diffraction zones and drived at 20GHz. As a result, calculated received gain using PO method is 33.01dB.

• Journal of Internet of Things and Convergence
• /
• v.2 no.1
• /
• pp.23-27
• /
• 2016

There is Generated Moire fringe by fresnel diffraction that explains one of light's physical phenomenon and interference. In this paper, we propose to generate true random numbers by Moire fringe should be used by not pseudo-random number in cryptosystem.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2005.10a
• /
• pp.79-82
• /
• 2005

Fresnel lens has number of applications in the optical systems because of its advantages. It is nearly flat lens that has small weight. It is conventionally used in lighthouse beacons, condensing unit of overhead projector and etc. Recently, demands of small size optical systems such as display units, information storage systems, optical detecting units had increased. Conventional manufacturing process of high quality Fresnel lens is direct machining. But it is not suitable for mass production because of high cost and long cycle time. Replication process is more suitable for mass production. But the Fresnel lens has number of sharp blade shape prism. In the replication process, this blade shape causes defects that can affect optical efficiency. In this study, replication process of blade shape pattern that has maximum height of $280{\mu}m$, aspect ratio 1.4 for Fresnel lens application.