• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.68-69
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• 2009

Heat Assisted Magnetic Recording (HAMR) is one of the most promising candidates for high density magnetic storages over 1 Tb/$in^2$ areal density. Since the precise light delivery to the head is a key factor to realize HAMR application, it is required to establish the light delivery using micro laser module and micro actuator. For the careful control of micro actuator, a laser module was designed including laser diode, optical fiber, collimating lens, and fabricated V-groove substrate. In addition, the basic aligning method between the laser module and HAMR head was studied by the detection of current change in photo diode due to the amount of reflected light from the head.

• 한국레이저가공학회지
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• 제11권2호
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• pp.33-38
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• 2008

Laser micromachining has increasingly been adopted in various advanced industries where the high-precision machining of large-area, high-density and multi-layered components is in a strong demand. To effectively meet the requirements, the laser micromachining process must be carefully monitored. In order to facilitate the development of a new laser micromachining process and/or a new system, we have fabricated a UV laser micromachining platform that is equipped with optical modules for monitoring the process online. They include a laser power stabilizing module, a module for laser-induced breakdown spectroscopy, and an auto-focusing module.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.460-463
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• 1993

In this paper, The laser transmitter module is designed as the subsystem of the high repetitive laser rangefinder. The module consists of high voltage power supply, high voltage control circuits, high voltage discharger, electro-optic Q-switch driver, and laser resonator. The high voltage power supply is composed of 2-phase flyback converter. And it has 220W power level and 78% conversion efficiency. From the Q-switch driver of the crossed porro resonator, the phase retardation voltage is switched from 600V to -1500V with 200ns falling time. The module can be operated up to 15Hz. And it generates the laser pulse which has 20ns width and 80mJ.

• 정보저장시스템학회논문집
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• 제7권1호
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• pp.36-41
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• 2011

The micro laser module was designed and prepared to deliver the light to the HAMR head. It consists of laser diode, photo diode and actuator to realize stable light delivery even though the head is fluctuated during the disk rotation. The optical evaluation was carried out with the actual distance between the light source and HAMR head with a range of reflectivity and it was found that the incident angle could be controlled within ${\pm}0.125^{\circ}$ to maintain same intensity into the HAMR head. It was also confirmed that the designed micro laser module is thermally stable without any severe effect on the magnetic head.

• 한국정밀공학회지
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• 제27권2호
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• pp.34-39
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• 2010

In order to achieve and maintain dimensional accuracy in laser micro-machining, dominant parameters such as laser power and laser focus position need to be monitored and controlled real time. Also, in order to selectively machine multi-layered materials, the material being presently machined need to be recognized. This paper presents an auto-focusing (AF) module to keep laser focus on a large-area surface; a real-time laser power stabilizing module based on optical attenuation; and a laser-induced breakdown spectroscopy (LIBS) module. With these monitoring modules, position error in laser focus on a 4" silicon wafer was kept below $4{\mu}m$, initially $51{\mu}m$, and laser power stability of a UV laser source was improved from 1.6% to 0.3%. Also, the material transition from polyimide to copper in machining of FCCL (flexible copper clad laminate) was successfully observed.

• 한국정밀공학회지
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• 제31권2호
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• pp.113-117
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• 2014

Laser Assisted Machining (LAM) was often used in process of difficulty-to-cut materials. In previous study, Laser assisted machining was a straight path processing using 1-axis manipulator in laser module. But 1-axis manipulator in laser module was able to process only straight path. So, in this study, laser module in laser assisted machining equipped to 2-axis manipulator. 2-axis manipulator has two motors. First motor is machining direction motor and second motor is Vertical Motor. Machining direction motor rotates in the direction of machining and vertical motor rotates vertical direction in the direction of machining. Machining path of laser assisted machining was considered diagonal path and curved path of laser heat source. This study calculated the 2-axis manipulator's rotation angle in diagonal path and curved path.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 D
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• pp.3016-3018
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• 2005

The PSD(Position Sensitive Detector) is a sensor for detecting the position of incident light. Because of its various advantages, it is used for position and angle sensing, optical range finders, laser displacement sensing, and etc. In the previous study of the position finding system, the laser tracking robot is developed. Small data rate and unidirectionality is the characteristics of data communication both DSP-based pan/tilt control board and the robot. If we can transmit data to the target using PSD sensor and laser diode module, there is no need for communication devices such as the bluetooth and wireless module. For this reason, this paper presents the new method for data transmission. Transmit data using RS-232 is modulated by a VTF(Voltage To Frequency) converter The laser diode module transmits the modulated data. And then the PSD sensor receive that data. Demodulation process is accomplished by the system which is consisted with trans-impedance amplifier, FTV(Frequency To Voltage) converter, and etc.

• 한국정밀공학회지
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• 제32권12호
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• pp.1031-1037
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• 2015

Laser assisted machining (LAM) is an effective method with which to effectively process difficult-to-cut materials. Simple machining processes, such as turning and linear tool paths, have been studied by many researchers. But, there are few research efforts on LAM workpieces using threedimensional shapes because of difficulties controlling the laser heat on workpieces with inclined angles or curved surfaces. Two methods for machining three-dimensional workpieces are proposed in this paper. The first is that the heat source shape and laser focal length are maintained using an index table. Second, a rotary type laser module is controlled using an algorithm to move the laser heat source in all directions. This algorithm was developed to control the rotary type laser module and the machine tool simultaneously. These methods are verified by a CATIA simulation.

• 한국정밀공학회지
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• 제29권5호
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• pp.506-509
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• 2012

Laser assisted machining is the processing method that preheating brittle materials by laser heat source and cutting the soften area. This processing applied to various industries because it can be cutting difficult-to-cut materials. However, the laser assisted machining appeared the limitations of processing for equipped with the spindle. So, it assumed separate model that spindle and laser assisted machining. In feed, the calculation of changing the angle of the laser module according to preheat point and the shape of the feed is important and it tried easy calculating changing angle of 1-axis Manipulator in separate model. In 3 types feed shape, angle of 1-axis Manipulator was calculated when fixed and moved in the outside of spindle. In this study, suggest 2 types of methods for laser module when fixed and moved.

• 마이크로전자및패키징학회지
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• 제24권1호
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• pp.91-101
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• 2017

최근 레이저를 이용하여 전자 소자 및 모듈을 절단하기 위한 많은 연구가 진행되고 있다. 본 연구에서는 레이저를 이용하여 LED 모듈을 초고속 절단하기 위한 기초 연구를 수행하였다. 특히 기존의 다이싱(dicing) saw의 절단 속도를 훨씬 능가하는 100 mm/s의 초고속 레이저 절단의 가능성을 검토하였다. 이를 위하여 LED 모듈의 구성 재료인 copper/ceramic 및 silicone/ceramic 이종 복합 기판을 제작하여 레이저 절단 후, 절단면의 표면 특성, 표면조도, 굽힘 강도를 다이싱 saw를 이용하여 절단한 샘플과 비교하였다. 복합 기판에 대한 최적의 레이저 절단 조건을 찾기 위하여, 세라믹 및 구리 단일 기판의 레이저 절단을 통하여 다양한 레이저 공정 조건들에 대한 영향 검토하였다. 절단면의 표면 특성이 가장 좋은 최적의 레이저 절단 조건은 Ar 보조 가스의 사용, 높은 레이저 파워 및 높은 보조 가스의 압력이었다. Copper/ceramic 및 silicone/ceramic 이종 복합 기판에 대하여 레이저 절단과 다이싱 saw로 절단한 기판의 절단면을 비교한 결과, 레이저로 절단된 기판이 다이싱 saw 절단에 비하여 표면이 거칠고 표면 특성이 약간 나쁘다. 레이저 절단면의 평균 표면조도는 약 $9{\mu}m$ 이며, 다이싱 saw로 절단된 절단면의 표면조도는 약 $4{\mu}m$ 이었다. 그러나 다이싱 절단의 절단 속도(3 mm/s)를 고려하면 레이저 절단면의 표면 morphology가 비교적 균일하고, 표면조도도 다이싱 절단의 경우와 큰 차이가 없기 때문에 어느 정도 만족할 만한 결과를 얻었다고 판단된다. 또한 레이저 절단된 기판의 굽힘 강도가 다이싱으로 절단된 기판의 굽힘 강도보다 동등하거나 약간 열세이었다. 그러나 향후 레이저의 절단 조건이 좀 더 최적화된다면 LED 모듈의 초고속 레이저 절단이 가능할 것으로 판단된다.