• Journal of Information Display
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• 제6권3호
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• pp.22-25
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• 2005

In this study, we attempted to find the origin of brightness non-uniformity in SLS poly-Si TFT AMOLED. By developing a suitable SLS process with a compensation circuit, we successfully improved the non-uniformity from 40% to 1.7%. In addition, we were able to fabricate 2.2" AMOLED display using SLS poly-Si.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1330-1333
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• 2006

The channel shape of FFL(Flat Fluorescent Lamp) was designed by optical simulation. It was possible to design and manufacture the channel in any shape using glass forming. The best suitable brightness uniformity of 83.7% was achieved.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.216-219
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• 2005

In recent, LCD becomes one of the main display devices and expected to have quite good market share during the next couple of years. The demand for low cost and high performance, however, is becoming severe as the competition among other display devices like PDP, OLED increases. To satisfy this demand from market, we need to optimize the parts or modules of the LCD, reduce the number of the assemble and enhance the process for the high brightness and uniformity of the LCD. The LCD consists mainly of LCD panel and Backlight unit(BLU). BLU, which takes big portion of the cost for LCD, consists of light source, light guide panel and many kinds of functional film. Recently light guide panel or film for BLU has micro patterns on its surface and consequently to reduce the number of parts and enhace the brightness and its uniformity. In this study, some methodologies for the fabrication of the master/stamper and molding the light quide panel are introduced for 50um pitch of prizm patterned substrate. Mechanical machining process is adapted and optimized to fabricate micro patterned stamper using the micro cutting tool. Injection molding technology is also developed to obtain uniformly replicated micro patterned products.

• 전기학회논문지
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• 제65권1호
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• pp.158-164
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• 2016

That's the reason why LED lighting has to employ AC power inlet. However, LED is a kind of diode, semiconductor, it's driven by DC power. With whis reason all of LED lighting should have AC/DC converter in its systems. This converter causes energy loss, it's the target for lesson the energy loss. To reduce this energy loss, DC power distribution structure can be used. LED lighting system using LVDC is a kind of DC power distribution structure, but LVDC has severe voltage drop which makes non-uniform brightness in lighting system. In this paper, we suggest a novel structure for the uniform brightness in LVDC LED lighting system using IoT based network system. The constructed test-bed system of suggested structure shows this structure can con control the brightness with uniformity.

• Transactions on Electrical and Electronic Materials
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• 제9권1호
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• pp.16-19
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• 2008

In this study, it was investigated about optical simulation in direct-type backlight design. Direct-type backlight has been used high-brightness backlight such as medical LCD application. The key parameter in designing direct-type backlight was consists of three geometrical dimension such as the distance of two lamps, the gap of lamp and reflection plate and the number of lamps. It has many of variations in optical design and it causes the different properties in backlight system. It shows the best values of above parameters; 26 mm of the distance of two lamps, 4.5 mm of the gap of lamp and reflection plate and 16 lamps. And we produced the specimen as above condition, and acquired good result in backlight such as the value of the brightness is 6423 nit in center of emission area and less than 5 % in brightness uniformity. It shows the effective ways of designing backlight system using optical simulation method for medical LCD application.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.906-910
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• 2005

본 논문에서는 이미 표준화 된 휘도에서 고 휘도를 향상을 시키기 위해서 휘도 향상에 직접영향을 미치는 실험모델을 제안 하였다. 국산램프(K社)와 일본램프의 제품에서 ${\phi}$2.6램프보다 ${\phi}$l.6램프을 사용함으로 세경화에 따라 200[cd/m$^2$]정도 휘도가 향상됨을 알 수 있었다. 기존에 BLU상에서는 LCD Panel을 장착하면 그 휘도는 초기램프 보다 약 1/100 - 1/200정도로 낮아진다. 시트 Variation에 따른 비교분석을 한 결과 시트 구성인 'LCP + DIFFUSER + BEF II(H) + BEFII(V)' 구성이 가장 고휘도 분포가 나타나는 것을 알 수 있으며, 고 휘도 구현을 하기위한 효율적인 구성 기준을 제안하였다.

• KIEAE Journal
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• 제11권6호
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• pp.53-62
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• 2011

This study aimed at suggesting improvement of lighting environment of the coffee house using study place. To this end, a series of field investigation was conducted in four possible target coffee houses around university. The field measurement included measurement of general illuminance and tabletop illuminance, observing illumination condition, and status of artificial lighting. Also, on-site questionnaire survey was administrated to 80 users of field measurement targets about using characteristics of coffee house and user's subjective response on light environment. The results are summarized as follows: (1) According to questionnaire survey, most of users checked 'learning (study and reading)' in 'purpose of coffee house using', and 'slightly dark' was checked most in each subjective response (brightness on general space and on tabletop at daytime/night); (2) as results of measurements on general illuminance and on tabletop illuminance during daytime, only one coffee house was suitable for standard; (3) as results of measurements on illuminance during night, all target coffee houses were not met the standard; (4) as results of uniformity ratios, almost uniformities of general illuminance were not met the standard except one case. The common problems of lighting environment of coffee house were analyzed as lack of daylight illumination e.g. having low amount of sunshine from skylight, un-uniformity of insolation by floor plan and absence of window blind, and un-uniformity of artificial luminous intensity e.g. lack of the number or brightness of artificial lighting, using the indirect lighting, using only local lighting, and non-uniform arrangement of artificial lighting.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.787-790
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• 2004

The large size and high brightness backlight system for LCD panel inspection equipment was designed, fabricated, and evaluated. The cold cathode fluorescent lamp (CCFL) instead of the hot cathode fluorescent lamp (HCFL) were used as the light source. The inverters for driving multi-lamp CCFL backlight systems were also designed and fabricated. The measured luminance of the fabricated CCFL backlight system was 20,000 cd/$m^2$ and the uniformity of the backlight was 85%. The fabricated backlight system was successfully applied to the LCD panel inspection equipment.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.130-133
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• 2003

Vertical Colour Selection (VCS) is an option for slim CRTs with increased sharpness and brightness. The direction of self-convergence of the DY is changed to vertical in order to obtain better spot uniformity, but the line scan direction remains horizontal. Hence, no video conversion is needed, contrary to transposed scan. In this paper we address two issues: First, there is a high risk of moire, since the scan lines and the phosphor stripes are parallel. We propose a feedback mechanism guiding the electron beams towards the middle of the mask slots. As positive side effects, the brightness is improved and the shadow mask can be made of a cheap type of steel. Secondly, VCS deflection coils have to satisfy different requirements than coils in ordinary CRTs. We discuss the design rules for self-convergent VCS coils and present simulation results.

• Journal of Information Display
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• 제2권1호
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• pp.34-37
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• 2001

We developed the tension mask of which thickness increased from 25 urn to 50 urn to reduce the mask cost and improve the vibration property. First of all, the limitation by which rail structure can support is calculated and the optimal thickness of mask is determined. To prevent the reduction of brightness and brightness uniformity, the dimensions of mask was reassigned. As a result, the increase of mask thickness brought about a reduction in cost and improvement of howling property which had been a weak point of flat CRTs.