• Design & Manufacturing
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• 제14권3호
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• pp.44-49
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• 2020

One of display trends today is development of high pixel density. To get high PPI, a small size of pixel must be developed. RGB pixel is arranged by evaporation process which determines pixel size. Normally, a fine metal mask (FMM; Invar alloy) has been used for evaporation process and it has advantages such as good strength, and low thermal expansion coefficient at low temperature. A FMM has been manufactured by chemical etching which has limitation to controlling the pattern shape and size. One of alternative method for patterning FMM is laser micromachining. Femtosecond laser is normally considered to improve those disadvantages for laser micromachining process due to such short pulse duration. In this paper, a femtosecond laser drilling for thickness of 16 ㎛ FMM is examined. Additionally, we introduce experimental results for controlling taper angle of hole by vibration module adapted in laser system. We used Ti:Sapphire based femtosecond laser with attenuating optics, co-axial illumination, vision system, 3-axis linear stage and vibration module. By controlling vibration amplitude, entrance and exit diameters are controllable. Using vibrating objective lens, we can control taper angle when femtosecond laser hole drilling by moving focusing point. The larger amplitude of vibration we control, the smaller taper angle will be carried out.

• 한국측량학회:학술대회논문집
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• 한국측량학회 2009년도 춘계학술발표회 논문집
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• pp.65-73
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• 2009

The terrestrial laser scanner measures the signal delay time of electronic circuit in EDM(Electronic Distance Measurement) Module for distance measurement. To measure signal delay time precisely, transmitting laser beam of terrestrial laser scanner is divided optically. Therefore, 10% of the laser beam power is entered into the electronic circuit and the others go out through lens. But, measure of delay time is severe in the laser scanner system that the laser beam power is changed dynamically by reflectance of a object, because characters like gain of electronic circuit involving APD(Avalanche Photo Diode) and so on are changed by incident laser beam. Therefore, we adapt ND(Neutral Density) filter that has grid pattern to the laser scanner system to keep constant the incident laser beam power. In this paper, we propose the simulation program for efficient design of ND filter pattern. Finally, to affirm simulation program, we conduct the experimental test of simulated ND filter that has linearly transmittance change, and we consider the experiment result.

• Current Optics and Photonics
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• 제4권2호
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• pp.127-133
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• 2020

We successfully constructed a passively Q-switched Yb:YAG laser ignitor pumped by a diode laser with low power and long pulse width. To the best of our knowledge, this is the first study to achieve a quasi-MW output power from an optimized Q-switch Yb:YAG laser ignitor by using a pumping diode laser module emitting at under a power of 23 W. The output pulse energy of our optimized laser is 0.98 mJ enclosed in a 1.06 ns pulse width, corresponding to a peak power of 0.92 MW.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.383-384
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• 2007

• 마이크로전자및패키징학회지
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• 제11권3호
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• pp.71-76
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• 2004

레이저다이오드 냉각을 위해 사용되는 TEC의 소비전력을 3차원 유한요소해석으로 예측하고 실험을 통해 해석결과의 타당성을 검증하였다. 레이저다이오드의 소비전력, 제어온도, 외기온도, 열전달경로의 열저항 등이 고려되었다. 저소비전력 모듈의 설계를 위해 해석결과를 바탕으로 Pellet의 숫자와 치수로 결정되는 TEC 형태에 따른 소비전력특성을 고찰한 결과 Pellet의 숫자가 적으며 접지면적이 작고 길이가 길수록, 즉 열저항이 증가할수록 소비전력은 감소하였다.

• 한국정밀공학회지
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• 제22권11호
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• pp.82-90
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• 2005

Recently, the in-line vision inspection has become the subject of growing research area in the visual control systems and robotic intelligent fields that are required exact three-dimensional pose. The objective of this article is to study the pc based in line visual inspection with the hand-eye structure. This paper suggests three dimensional structured light measuring principle and design method of laser sensor header. The hand-eye laser sensor have been studied for a long time. However, it is very difficult to perform kinematical analysis between laser sensor and robot because the complicated mathematical process are needed for the real environments. In this problem, this paper will propose auto-calibration concept. The detail process of this methodology will be described. A new thinning algorithm and constrained hough transform method is also explained in this paper. Consequently, the developed in-line inspection module demonstrate the successful operation with hole, gap, width or V edge.

• 한국광학회지
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• 제17권6호
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• pp.489-492
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• 2006

평판도파로 상에 FP-LD와 샘플격자를 하이브리드 집적하여 듀얼 모드로 발진하는 외부 공진기 레이저를 구현하였다. 샘플격자에 인가되는 전류를 50mA에서 55mA로 변화시킴으로써 듀얼 모드간의 beat 주파수를 132GHz에서 406GHz로 스위칭할 수 있었다.

• 한국정밀공학회지
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• 제31권2호
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• pp.119-123
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• 2014

Recently, laser processing technologies have been developed in many different industrial fields. The laser processing technologies are widely being applied such as laser assisted machining, cladding, heat treatment and coating. In the laser modules of the laser assisted machining system, laser lens is very important for accuracy and productivity of product. As the laser beam size, shape and focusing distance change, heat input energy of preheating point can be changed, the laser module of the laser assisted machining system should be equipped with various lenses differing beam size, beam shape and focusing distance. In this study, the rotary and linear laser modules are suggested. The finite element analysis is carried out to certify the static and dynamic stabilities of the developed laser modules. Finally, the rotary and linear laser modules have been fabricated successfully using the analysis results.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.35.3-35
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• 2001

Developed is an optical auto-inspection system to detect some microscopic defects on the Inside surface of the hydraulic automobile brakes at the production line. A small cylindrical detection module with a solid laser source at its center has two rings of optical fibers to separately collect light reflected and scattered from the defects on the surface. The cylindrical brake part rotates with respect to the detection module that will move parallel to the rotational axis of the cylinder. Thus, the optical module can scan the whole inside surface area. The automatic detection of the defects is to compare the intensity distributions ...

• 한국컴퓨터산업학회논문지
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• 제8권1호
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• pp.49-56
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• 2007

빔의 열적효과는 세포조직의 서로 다른 구성성분과 레이저 빔의 서로 다른 파장에서 다른결과를 나타내며 세포조직에서 온도증가는 먼저 응고가 이루어지고, 절단이나 탄화과정이 일어나며 $300^{\circ}$이상에서는 세포조직의 파괴에 의한 증발이 발생하게 된다. $CO_2$ 레이저는 최소한 조직손상으로 이러한 효과를 얻는데 최적이라고 보며 0.1mm의 최소한의 세포조직 깊이에서 일어나는 효과의 근본적인 장점은 생체조직이나 내장기관에 안정적이다. $CO_2$레이저사용에 있어서 단점은 무엇보다도 세포파괴에서 생성되는 입자들의 부품흡착 등으로 결과적으로 레이저의 출력감소가 일어나는데, 영 전압, 영 전류 스위칭 포워드 컨버터를 도입하여 기존의 하드 스위칭 포워드 컨버터에 있어서 Turn-off, on시 발생되는 스위칭 방식을, 적용함으로써 1차 측 스위칭 소자의 Turn-off, on시 영전압, 영전류 스위칭을 이루어 정밀도가 요구되는 산부인과용 $CO_2$ 연속 형 레이저의 고압출력 모듈에 따른 펄스 트랜스의 안정화에 필수적으로 기여하며, 레이저 출력과 안정화가 되도록 설계 및 제작한 결과, 기존제품보다 향상된 결과를 가져왔다. 추후 시스템적으로 보완을 하면 우수한 결과가 될 것으로 사려된다.