• Journal of Magnetics
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• v.19 no.1
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• pp.32-36
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• 2014

The purpose of this study was to investigate the effect of pulsed magnetic field (PMF) and low frequency low level laser (LFLLL) stimuli on acupoint LI4 (Hegu) using photoplethysmography (PPG). Our PMF system was designed to generate maximum intensity of 0.20 T at a transition time of 0.16 ms, with pulse intervals of 1 Hz. The diode laser with wavelength of 650 nm and power of 5 mW was also employed. It was observed the change of the pulsating blood volume through measuring PPG signals from both hands. These results imply that stimulating acupoint LI4 with PMF and LFLLL improves the circulation of peripheral vascular system. In particular, PMF stimulation brings a big improvement of the blood flow even with short term stimulation of 3-4 minutes compared to LFLLL stimulus.

• Journal of Oral Medicine and Pain
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• v.21 no.1
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• pp.25-36
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• 1996

To investigate the effect of low level laser therapy, the author selected 37 dental students with tender points in both masseters and trapeziuses, also measured maximum comportable opening(MCO), Numerical analog scale(NAS) and pressure pain threshold (PPT). 20 subjects were assigned randomly and were treated with GaAlAs diode laser after ultrasound. The other 17 subjects were treated with ultrasound and laser without irradiation. All the subjects were treated after 2 and 4 day respectively and were examined again after 6 days. And the obtained results were as follows : 1. The MCO of irradiated group increased more significantly after treatment than non-irradiated group. 2. The NAS of irradiated group decreased more significantly after treatment than non-irradiated group. 3. The PPT or irradiated group increased more significantly after treatment than non-irradiated group.

• Journal of Biomedical Engineering Research
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• v.28 no.3
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• pp.392-396
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• 2007

In this paper, we develop a new system to visualize the blood flow map in skin tissue, using the technique of Laser Speckle Flowgraphy (LSFG). The measuring unit consists of the laser diode, imaging system, line sensor, scanning mirror, and one-board microcomputer. The speckle signal is analyzed and sent to a PC, where the blood flow in a tissue area of $14mm{\times}26 mm$ is evaluated and displayed in a 2-D color map. It is demonstrated that the new LSFG instrument is useful to evaluate the degree of allergic reaction in patch test.

• Transactions of Materials Processing
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• v.24 no.5
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• pp.354-360
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• 2015

AHSS (Advanced High Strength Steels) has been increasingly employed by global automotive OEMs in order to satisfy strengthened regulations and reduce weight for fuel efficiency. Hot stamping using boron steels in AHSS increases not only formability but also strength. The typical hot-stamped automotive part is the center pillar that is critical for vehicle side impact. However, the hot-stamped part can be risky for the passenger safety caused by brittle fracture under a vehicle collision. The high power diode laser is suitable for the heat treatment giving AHSS increased elongation that prevents brittle fracture in car crash. Therefore, local softening by laser heat treatment for energy absorption area on the hot-stamped part improves crash-worthiness.

• Journal of Information Display
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• v.11 no.1
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• pp.12-16
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• 2010

The effect of the crystallization and activated annealing of Si films using an excimer laser and the new CW blue laser are described and compared with furnace annealing for application in advanced TFTs and for future applications. Pulsed excimer laser annealing (ELA) is currently being used extensively as a low-temperature poly-silicon (LTPS) process on glass substrates as its efficiency is high in the ultra-violet (UV) region for thin Si films with thickness of 40-60 nm. ELA enables extremely low resistivity relating to high crystallinity for both the n- and p-type Si films. On the other hand, CW blue laser diode annealing (BLDA) enables the smooth Si surface to have arbitral crystal grains from micro-grains to an anisotropic huge grain structure only by controlling its power density. Both annealing techniques are expected to be applied in the future advanced TFT systems.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1335-1336
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• 2008

A compact diode-pumped microchip(DPM) green light source which consist of pump LD, $Nd:YVO_4$, KTP and a built-in thermoelectric element has been fabricated for laser projection display. The volume of the source is as small as $0.7\;cm^3$ and we obtained the output power of 25mW with the average electric power consumption in pump LD of 304mW which correspond to the electrical-to-optical efficiency of 7.8%. Another approach using quasi phase matching(QPM) technique has been attempted. We obtained the output power of 90mW of green beam with 350mW pumping of a $Nd:YVO_4$ laser with 20-kHz rep. rate and 10-ns pulse duration. Detailed characteristics and issues of the DPM and QPM green light sources will be addressed.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.9
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• pp.1727-1735
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• 2002

The usage of beam scanning type laser marker is rapidly increasing in the field of semiconductor equipment. A device called ″beam adjuster″ is employed to adjust the visible diode laser, which points the marking position for various setting. The device is very sensitive to manufacturing tolerance and assembly condition. Axiomatic approach has been applied to the design of the device. An existing design is analyzed based on the Independence Axiom. The existing design is found to violate the axiom. Two new designs are proposed to satisfy the Independence Axiom. The Information Axiom is utilized to evaluate the designs. A design is selected to have the minimum information content. The significance of this research is that a full cycle of axiomatic design is applied to a real engineering product.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.145-149
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• 1997

A laser mesurement system, a modified Michelson interferometer,which can accurately measure high speed length and position of servomechanisms by detecting a phase shift in the measurement beam using an optical interference was developed. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. The refractive index of the ambient air was calibrated through the Edlen's formula. The system achieved a resolution of .lambda./40,16nm, a maximum allowable measurement speed of 600 mm/sec, and a length measurement range of 1500mm. Performance of the system was evaluated on the machining center in short and long length measurements

• Korean Journal of Optics and Photonics
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• v.4 no.3
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• pp.289-293
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• 1993

A Nd:YLF laser pumped by a CW GaAlAs laser diode(LD) at 792 nm has been designed and fabricated. The output power was investigated as a function of LD spectrum and pump power. A folded laser resonator was desinged to compensate for the astigmatism produced at the Brewster surface of Nd:YLF rod. We obtained output power of CW 1.1 Watt when the pumping power was 2.8 Watt and the output wavelength of LD was temperature tuned to the peak absorption line of Nd:YLF. The overall efficiency was 39 % and slope efficiency was 41 %.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.53-81
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• 2006

A COG(Chip on Glass) bonding process that is one of display packaging technology and bonds between driver IC chip and a glass panel using ACF(Anisotropic Conductive Film)has been investigated by using diode laser. This method is possible to raise cure temperature of ACF within one second and can reduce the total process time for COG bonding by a conventional method such as a hot plate. Also we can get good pressure mark on the surface of electrodes and higher bonding strength than that by convention method. Results show that laser COG bonding can give low pressure bonding and decrease a warpage of panel. We believe that it can be applied to fine pitch module.