• 한국산학기술학회논문지
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• 제22권2호
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• pp.134-138
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• 2021

스마트폰 등에서 사용되는 고성능 디스플레이에는 다양한 종류의 정밀한 플라스틱 박막 필름(Plastic Thin Film)이 사용되고 있다. 롤투롤(Roll-To-Roll) 공정으로 제조되는 플라스틱 박막 필름은 생산 공정 중에 실시간으로 필름의 두께가 계측되고, 정확하게 관리되어야 한다. 필름 제조 과정에서 필름에 장력이 작용하면서 주름이 발생되고, 이러한 주름 발생은 필름의 두께 방향과 두께 측정기의 광축이 서로 경사지게 한다. 결국 두께 측정기는 필름의 수직 두께가 아닌 경사진 두께를 측정하게 됨으로써 실제 두께보다 더 큰 값으로 측정하게 된다. 본 연구에서는, 플라스틱 필름의 경사로 인하여 발생하게 되는 두께 측정기에서의 계측값 오차를 보정하기 위하여, 필름의 경사 각도를 계측하는 연구가 진행되었다. 플라스틱 필름에 슬릿 빔 레이저를 조사하고, 필름에서 반사되는 슬릿 빔 레이저가 PSD(Position Sensitive Device)에 맺히는 광학 시스템을 구성하였으며, 실험을 통하여 필름의 경사 각도와 PSD 출력값의 관계를 1차 방정식 형태로 구하였다. 이를 이용하여 필름의 경사 각도를 측정하는 장치가 구축되었으며, 250KHz의 속도로 경사 각도의 측정이 가능하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 B
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• pp.540-542
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• 1998

The Position Sensitive Detector(PSD) is an useful device which can be used to measure the position of an incidence light in accuracy and in real-time. In this paper, 2-D PSD sensor is used to measure the 2-D position of moving object with light source. To get the position of light source from PSD sensor exactly, we propose two position computation methods ; the parameter calibration and neural network. Experimental data is presented that offer the comparision between two methods and demonstrates the effectiveness of proposed approach.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.536-539
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• 2003

This paper presents a study of position tracing system for Underwater Vehicle Robots(UVR) that is inspecting an atomic furnace. This system development is the basic research for the purpose of position estimation of UVR and preventing that UVR crash into the wall of an atomic furnace. For this purpose, Pan/Tilt Unit that is attached Laser is pointing PSD(Position Sensitive Detector) Sensor which is stuck to the upper side of UVR. Through this action, we can find the Position of UVR. In this paper, we construct the system for aiming the laser pointer at PSD Sensor using pan/tilt and study the optimum algorithm for finding the optional position that is located at the space which is pointable area by Laser device.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2167-2169
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• 2004

The main concern for a displacement measurement is the performance of a sensor such as speed, resolution, accuracy and so on. The mainly used sensors are a linear CCD(charge coupled device) and a PSD(position sensitive detection) as a non-contact type. The output value of a linear CCD is so sensitive to a temperature change that it needs a cooling device. Additionally, because of its structural problem, there are some limits in resolution and speed, and it needs a complex image processing algorithm. Also, PSD has some disadvantages like sensitivity to environmental lights and nonlinearities. Like this, a linear CCD and PSD have their own characteristics and if we know them well, we can choose the one of the two sensors properly in some applications according to purposes. In this paper, I performed which one is superior to the other among the two sensors in terms of accuracy, resolution, measurement speed, signal to noise ratio.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.471-472
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• 2010

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제49권2호
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• pp.140-148
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• 2000

In this paper, using surface micromachining technology with thick photoresist and aluminum, an SLM(Spatial Light Modulator), which is applied to the fields of adaptive optics and pattern recognition system, was fabricated and the electromechanical properties of the fabricated micro SLM are measured. In order to maximize fill-factor and remove mechanical coupling between micro SLM actuators, the micro SLM is composed of three aluminum layers so that spring structure and upper electrode are placed beneath the mirror plate, and $10\times10$ each mirror plate is individually actuated. Also, the micro SLM was designed to be able to modulate phase and amplitude of incoming light in order to have a continuity of phase modulation of incoming light. In the case of amplitude and phase modulation, maximum vertical displacement is 4$\mum$, and maximum angular displacement is $\pm4.6^{\corc}$ respectively. The height difference of the fabricated mirror plate was able to be reduced to 1100A with mirror plate planarization method using negative photoresist(AZ5214). The electromechanical properties of the fabricated micro SLM were measured with the optical measurement system using He-Ne laser and PSD(position sensitive device).

• 한국정밀공학회지
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• 제16권7호
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• pp.40-50
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• 1999

Recently, a laser displacement sensor is widely used for the manufacturing automation. The sensor is generally composed of a diode laser and a light receiving device. The diode laser emits a laser beam and the receiving device detects the light reflected from the measured object. The object position is obtained based upon triangulation method. As a light receiving device, a PSD is usually utilized since its structure is very simple and rugged and has a high accuracy. Although the theoretical relationship for this sensor had been developed, the characteristics of the sensor have not been much experimentally studied. In this paper, several experimental results will presented. The measurement accuracy is affected by the surface conditions such as the reflectance characteristics, the angle of the object's surface and the laser intensity. In addition, it is found that the PSD and the signal processing circuit have nonlinearities and showed that those nonlinearities can be reduced by controlling the emitting laser intensity.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 학술대회 논문집 정보 및 제어부문
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• pp.339-340
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• 2008

로봇의 현재 위지 추적은 무인 로봇 자동 항법시스템의 중요 기술로 센서 데이터로부터 로봇의 위치를 결정하고 환경맵을 구성하는 것이다. 기존 방법으로는 초음파, 레이저 등의 거리 측정 센서를 이용해 로봇의 전역 위치를 찾는 방법과 스테레오 비전을 통한 방법이 개발되었다. 거리 측정 센서만으로 로봇위치 추적 알고리즘은 계산량이 감소하고 비용이 적게 들지만 센서오차율 및 환경장애에 따른 오류가 크다. 이에 반해 스테레오 비전 시스템은 3차원 공간영역을 정확히 측정할 수 있지만 계산량이 많아 고사양의 시스템을 요구하고 알고리즘 구현에 어려움이 있다. 따라서 본 논문에서는 단일 카메라 영상과 PSD(position sensitive device) 센서를 사용하여 로봇의 현재 위치를 추적하고 환경맵을 구성하여 자율이동이 가능한 시스템을 제안한다.

• Journal of Mechanical Science and Technology
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• 제15권10호
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• pp.1369-1379
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• 2001

This paper focuses on a development of a sensor system measuring locations of a vehicle to localize a mobile robot while it tracks on the track (location sensor) . Also it focuses on a system configuration identifying the vehicle's orientation and distance from the object while it is stationary at certain station (position sensor) . As for the location sensor it consists of a set of sensors with a combined guiding and counting sensor, and an address-coded sensor to localize the vehicle while moving on the rail. For the position sensor a PSD (Position Sensitive Device) sensor with photo-switches sensor to measure the offset and orientation of the vehicle at each station is introduced. Both sensor systems are integrated with a microprocessor as a data relay to the main computer controlling the vehicle. The location sensor system is developed and its performance for a mobile robot is verified by experiments. The position measuring system is proposed and is robust to the environmental variation. Moreover, the two kinds of sensor systems guarantee a low cost application and high reliability.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.119-122
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• 2001

This paper deals with new type of active magnetic bearing (AMB) for the linear motors. We adopted optical sensing mechanism for the gap sensing. Using the laser and the PSD (Position Sensitive Device), the absolute rotor position is obtained independent of the profile of the guide rail. With this measurement, the rotor can be controller to follow the straight beam of the laser. Another advantage of optical sensing mechanism might be the elimination of the possible interference between the proximity sensor and the electro-magnet. By adopting the push-full actuating mechanism, the bearing stiffness is increased near the equilibrium position. For the simplicity, distributed control system is constructed. Eight independent PID control algorithm is used with the full order observer. Several simulation md test results are presented.