• 소성∙가공
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• 제15권1호
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• pp.27-33
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• 2006

It is necessary to improve the pattern replication and birefringence in LGP(Light guide panel) for better optical performance. In the present paper, the effects of injection-compression and injection-press mode with normal injection mold on the distribution of transcription of pattern and birefringence were studied. It was found that the values of pattern replication was improved and the birefringence was reduced for the cases of low initial clamping force in injection-compression mode and for the cases of longer mold opening length in injection-press mode, repectively.

• 소성∙가공
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• 제15권1호
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• pp.71-75
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• 2006

In recent, various shapes of pattern in micron or nano scale are adapted in many applications due to their good mechanical or optical properties. Light guide panel (LGP) of the LCD is one of important applications for micro pattern and micro prism shape is one of the typical patterns. The size of the surface patterns in most applications is decreasing to the order of micron or even under micron. On the other hand, the area to be patterned keeps enlarging. These two trends in patterned products require tooling micro patterns on large surface, which has still many technical problems to be solved mainly due to pattern size and the tooling area. In this study, we fabricated prism shape of patterns using diamond cutting tool on some metal core and plastic core like PMMA. Some cutting conditions were investigated including cutting force, cutting depth and speed for different core materials.

• 소성∙가공
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• 제15권9호
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• pp.686-691
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• 2006

Powder blasting technique was introduced to micromachine the micro patterns of circular and rectangular shape in LGP mould. The machinability of these patterns and matt treatment by powder blasting were verified. Then a prototype of LGP was injected by the developed LGP mould with micro patterns. Shape analysis of micro patterns and performance test of the injected LGP were carried out. The results showed printless LGP with micro patterns could be produced by just single injection using the mould with micro patterns, and powder blasting technique could be successfully applied to micrornachining of micro patterns and matt treatment of LGP mould.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.698-700
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• 2003

LGP (Light-Guide Panel) of TFT-LCD Backligh/Frontlight is one of the major components which affect on the product quality of LCD. Since the brightness distribution of LGP is sensitive to the process error in manufacturing, the optical characteristics such as reflection and absorption of LGP pattern should be modeled including the process error. LGP is developed by using the fast and reliable design technology, which uses the concept of the inverse-design, makes the model on the characteristics of uncertainty in the manufacturing process, and designs the dispersion pattern analytically without try-and-error by using an artificial intelligence. The PEA(Process-Error-Adaptive) design gives the best solution in handling the process error. The offset of target in feedback system makes such the best pattern design possible that the brightness distribution is nearly same (more than 90%) with target in regardless of the miscellaneous errors in mass production. The present design method has been also applied to frontlight and multi-side-lamp(eg., four-side-four-lamp) backlight.

• 대한기계학회논문집A
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• 제29권3호
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• pp.361-368
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• 2005

LGP(Light-Guide Panel) of LCD backlight is one of the major componets which affect on the product quality of LCD. The LGP with multi-side lamp has been analized for pattern design with the uniform distribution of brightness. When given the uniform distribution of brightness as target, the distribution of dot pattern has been designed for superposed distributions of brightness for each lamp. Multi-side lamp has been tested for various types such as ㄴ-, ㄷ-, and ㅁ -shapes. The present study enhances the possibility of LGP with multi-side lamp by showing the pricise control of brightness distribution.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.533-534
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• 2006

Micro pyramid pattern and its array are designed to enhance the brightness and its uniformity of LGP which is one of key parts in LCD. The designed micro pyramid patterns are fabricated on a Si-wafer first through MEMS process and then a Ni-stamper is electro-plated from the Si pattern master. Adopting the fabricated Ni-stamper, LGPs are injection molded at different mold temperatures and the fidelity of the pattern replication is estimated for each molding conditions and pattern locations. The replicated patterns are found to have some defect such as local short shot or micro weld line which are believed to have negative effect on the performance of the LGP.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2008년도 추계학술발표논문집
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• pp.358-361
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• 2008

본 논문에서는 열화상촬영기 및 온도분포 해석 프로그램을 이용하여 금형가열온도와 실제 금형온도의 온도편차를 비교하여 금형가열 시 Stamper 표면의 온도분포를 해석하였다. 또한 전열가열방식(E-MOLD)을 이용하여 복합기능 도광판(Prismless LGP)을 제조하였고, 금형온도에 따른 복합기능 도광판(Prismless LGP)의 광특성 평가를 하였다. 그 결과 금형온도가 증가할수록 패턴 전사성 향상으로 인해 휘도 또한 증가하였고, 특히 유리전이온도($140^{\circ}C$) 이상에서 크게 상승하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
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• pp.110-113
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• 2005

In recent, various shapes of pattern in micron or nano scale are adapted in many applications due to their good mechanical or optical properties. Light guide panel (LGP) of the LCD is one of important applications for micro pattern and micro prism shape is one of the typical patterns. Many applications have the patterns on their surface and the size of the pattern keep decreasing down to the order of micron or even under micron. On the other hand, the area to be patterned keeps enlarging. These two trends in patterned products require tooling micro patterns on large surface, which has still many technical problems to be solved mainly due to pattern size and the tooling area. In this study, we fabricate prism shape of patterns using diamond cutting tool on some metal core and plastic core like PMMA Some of cutting conditions are investigated including cutting force, cutting depth and speed for different core materials.

• 대한기계학회논문집A
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• 제28권4호
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• pp.362-369
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• 2004

LGP(Light-Guide Panel) of LCD backlight is one of the major componets which affect on the product quality of LCD. The optical relation between brightness and pattern has been investigated for LGP with the uniform distribution of brightness. When given the brightness distribution as target, the solutions of pattern distribution is not unique. Each solution of pattern designs shows the different brightness intensity even though they have the same brightness distribution with target's one. The manufacturing condition of pattern has an influence on the possibly-maximum-brightness intensity among the solutions of pattern design. The present study has examined the effects of LGP thickness, pattern shape errors, and reflection film on the optical characteristics of LGP.

• 대한기계학회논문집A
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• 제30권8호
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• pp.957-964
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• 2006

As the requirement of LCD products which are large screen and have high brightness increases, the role of light guide panel (LGP) of which micro-features diffuse the light uniformly on surface is getting important. In general, there are many errors in machining like machine tool errors process error, setup error and etc. The amount of setup error in general machining is not so big in comparison with the others, so it is mostly neglected. But, especially in v-groove micromachining, setup error has a significant effect on micro-features. Low quality product and high cost are resulted from setup error. In v-groove micromachining, to confirm the effect of setup error, it is identified and then setup error synthesis model is derived from analysis of tool and workpiece setup. In addition, to predict the micro-features affected by setup error and enhance the production efficiency, the setup condition satisfying the tolerance of micro-features is geometrically analyzed and presented.