• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1167-1171
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• 2008

The flow and thermal performance of the skiving and louver fin type heat sinks for the cooling system of the small LED projector were experimentally evaluated. A small fan tester based on AMCA standards was used to control and measure the air flow rate into the heat sink. Three heat blocks were used to simulate the heat and light sources(red, green and blue) of the small LED projector. We measured the pressure drop, temperatures and input power at the specific air flow rate and discussed those results. As a result, it is found that the louver fin type heat sink has higher pressure drop and lower thermal resistance than the skiving type. From the comparison of the temperature of the heat block between skiving and louver fin type, the louver fin type heat sink was found to be more suitable for cooling the high power heat source than skiving type. The thermal performance of the fan-sink(louver fin type) system was discussed with the picture taken by a thermal video.

• 전자공학회논문지 IE
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• v.48 no.4
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• pp.19-24
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• 2011

Advances in mobile communications, portable computing and personal electronics have led consumers to demand large viewing area, bright, high resolution, compact and long life portable displays. Pico projectors are the latest technology to prove that big things often do come in small packages. Our goal in this paper was to implement a portable, low power, and highly adaptable miniature pico projector system. The pico projector is designed many functions of the pico projector solutions, multimedia, and T-DMB broadcasting.

• Proceedings of the Optical Society of Korea Conference
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• 2008.02a
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• pp.139-140
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• 2008

• International Journal of Internet, Broadcasting and Communication
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• v.14 no.2
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• pp.10-16
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• 2022

As an important part of virtual production, In-camera VFX is the process of shooting actual objects and virtual three-dimensional backgrounds in real-time through computer graphics technology and display technology, and obtaining the final film. In the In-camera VFX process, there are currently only two types of medium used to undertake background imaging, LED wall and chroma key screen. Among them, the In-camera VFX based on LED wall realizes background imaging through LED display technology. Although the imaging quality is guaranteed, the high cost of LED wall increases the cost of virtual production. The In-camera VFX based on chroma key screen, the background imaging is realized by real-time keying technology. Although the price is low, due to the limitation of real-time keying technology and lighting conditions, the usability of the final picture is not high. The short-throw projection technology can compress the projection distance to within 1 meter and get a relatively large picture, which solves the problem of traditional projection technology that must leaving a certain space between screen and the projector, and its price is relatively cheap compared to the LED wall. Therefore, in the In-camera VFX process, short-throw projection technology can be tried to project backgrounds. This paper will analyze the principle of short-throw projection technology and the existing In-camera VFX solutions, and through the comparison experiments, propose a low-cost solution that uses short-throw projectors to project virtual backgrounds and realize the In-camera VFX process.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.135-140
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• 2013

This paper deals with noise reduction on a light source driving board in a projector. We analyze causes of noise/vibration in the circuit with the present increasing use of LD and LED driving boards. The main source of noise is the MLCC in the driving board. Our aim is to investigate how the mechanical arrangement of the circuit elements affects noise reduction. The result of our experiment shows that noise can be reduced by symmetrical arrangement and slots in PCB. This result is expected to facilitate a variety of applications for manufactures without a need to change circuit elements.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.560-563
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• 2006

LED is promising for the application of specialty illumination. Thiscolor management system, V-core, with LED light sources and the structure of V-core for LCoS projector has been proposed to improve the primary saturation, uniformity and contrast. We designed the high efficient LED modules for high brightness requirement. The LED module can operate in narrow-direction indicator, $12^{\circ}$.

• Journal of Information Display
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• v.11 no.1
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• pp.28-32
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• 2010

A mini-projector prototype employing a LED light source, a nontelecentric structure, and an LCOS panel for application in the integrated 3D display was fabricated. A seamless image was obtained by tilting an array of mini-projectors. Seamless quality was created by the excellent uniformity of the projection intensity on the mini-projector's screen, which was simulated as 98.34%. Great uniformity can be realized by optimizing the design of the light source and the optics configuration, which is the key to such realization.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1331-1334
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• 2008

In this paper, we developed a novel hyperreality display called the Head Dome Projector (HDP). The HDP is a head-mounted display consisting of a dome-shaped screen with a very small radius of 40 cm, a mobile projector with ultra-wide projection lens and LED light sources. The main feature of the HDP is very wide viewing angle of 160 degrees horizontally by 120 degrees vertically comparable to the human visual field of view without head tracking and 360 degrees by 360 degrees with head tracking. According to our subjective evaluation comparing the HDP with a flat-panel display (FPD), the HDP realizes hyperreality 2.5 points higher than that realized by an FPD in the case of ${\pm}5$ level evaluation for HD motion images.

• Journal of the Semiconductor & Display Technology
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• v.10 no.1
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• pp.17-22
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• 2011

LEDs(Light Emitting Diodes) are becoming widely used and increasingly in demand. Quality inspection of the LEDs has become more important. Two-dimensional inspection systems are limited in inspection capability, so threedimensional(3-D) inspection systems are needed. In this paper, a cost-effective and simple 3-D measurement system of LED packages using phase measuring profilometry(PMP) is proposed. The proposed system uses a pico projector to project sinusoidal fringe patterns and to shift phases instead of piezocrystal. It was evaluated using extremely accurate gauge blocks, yielding excellent repeatability of about 12 um(3-sigma). 3-D measurements of various LED packages were performed to demonstrate the applicability and efficiency of the proposed system.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.23 no.6
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• pp.495-501
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• 2013

This paper deals with noise reduction on a light source driving board in a projector. We analyze causes of noise/vibration in the circuit with the present increasing use of LD and LED driving boards. The main source of noise is the MLCC in the driving board. Our aim is to investigate how the mechanical arrangement of the circuit elements affects noise reduction. The result of our experiment shows that noise can be reduced by symmetrical arrangement and slots in PCB. This result is expected to facilitate a variety of applications for manufactures without a need to change circuit elements.