• 정보저장시스템학회논문집
• /
• 제2권4호
• /
• pp.236-239
• /
• 2006

Glass micro molding process is the most suitable process for fabricating high precision glass microlens amy at low cost. A new glass micro molding process was proposed. Tungsten carbide mold was fabricated by imprinting and sintering process to overcome the difficulties of the conventional process. In the glass micro molding process, process conditions such as processing temperature and compression force were changed. Geometrical properties of the replicated glass microlens array were measured and compared at variety process conditions. The condition of glass micro molding process was optimized. The experimental result showed that developed process was effective to produce a glass microlens array.

• 한국전기전자재료학회논문지
• /
• 제27권5호
• /
• pp.307-311
• /
• 2014

Because of a waveguiding effect and total internal reflection caused by a difference in refractive indices, only 20% of generated light is emitted to the air and the rest is trapped or absorbed in the device. An improvement of outcoupled efficiency of organic light-emitting diodes was studied using a microlens array. Mold of microlens array was fabricated by using photo-lithography with the AZ9260 photoresist, and the microlens array was formed onto the glass substrate using the UV curing agent named ZPU13-440. Device structure consists of microlens/glass/ITO/TPD/$Alq_3$/LiF/Al. It was found that there is an improvement of external quantum efficiency by about 20% at the same current density for the device with the microlens array compared to that of the reference one. Simulated outcoupled efficiency shows the improvement by about 20% for the device with the microlens array compared to that of the reference one. These results are consistent with the experimental ones.

• 한국광학회지
• /
• 제18권6호
• /
• pp.441-446
• /
• 2007

OLED 소자는 유리기판과 공기 층의 경계면에서 발생하는 전반사와 ITO-유기층으로 형성되는 광도파로를 따라 진행하는 도파모드 결합으로 인해 내부에서 생성된 빛의 80% 이상이 외부로 추출되지 못하게 된다. 본 연구에서는 마이크로 렌즈 어레이와 회절격자 레지스트 층을 이용하여 소자 내부에서 손실되는 빛을 외부로 추출시킴으로써 OLED의 발광효율을 향상시킨다. 마이크로 렌즈 어레이를 이용하여 유리기판-공기 전반사로 인해 내부에 갇히는 빛을 외부로 출력시키고, ITO 와 유기물 사이에 회절격자 레지스트 층을 삽입하여 ITO-유기층 광도파로에 갇힌 빛들을 수직방향으로 추출될 수 있도록 하였다. 제작된 OLED 소자에 전류밀도 $20mA/cm^2$를 인가한 경우, 마이크로 렌즈 어레이를 적용한 OLED에서 22%의 효율 개선을 얻었고, 회절격자 레지스트 층을 가지는 OLED 의 경우 41%의 효율개선을 얻을 수 있었다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2004년도 추계학술대회논문집
• /
• pp.36-39
• /
• 2004

Glass molding is an advantageous method to manufacture glass micro optical components. However, it is difficult to make Tungsten Carbide core for glass microlens array. We have developed novel method to fabricate Tungsten Carbide core for micro glass components using pressure forming. Silicon masters were fabricated by micro machining. Tungsten Carbide core was fabricated by pressure forming and sintering. And we made high quality surface of Tungsten Carbide core by using the magnetic-field-assisted polishing process.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.1682-1683
• /
• 2011

Through-silicon microlens array has been implemented using glass thermal reflow process. Design, numerical analysis, fabrication, and measurement results are discussed. Microlenses with six different volumetric dimensions were successfully fabricated and characterized. Radius of curvature of each microlenses were measured with less than 1% deviation compared to calculated value. Measured average roughness of the microlens surface was 16.5 nm.

• 한국광학회지
• /
• 제16권4호
• /
• pp.340-344
• /
• 2005

화염가수분해 증착법(FHD : Flame Hydrolysis Deposition)으로 제작된 Ge이 첨가된 BPSG(Boro-Phospho-Silicate-Glass)막의 표면을 절단톱(dicing saw)을 이용하여 일정한 깊이로 절단함으로써 각 단위 마이크로렌즈 셀들을 형성시켰다. 또한 절단된 각 단위 마이크로렌즈 셀들을 가열용융(thermal reflow) 방법을 이용하여 $1200^{\circ}C$에서 가열용응시킴으로써 직경이 $53.4{\mu}m$인 마이크로렌즈 어레이를 제작할수 있었다. 이 때 렌즈간 간격은 $70{\mu}m,$ 렌즈 두께는 약 $28.4{\mu}m$이었다. 제작된 마이크로렌즈 어레이의 형상을 이미지-프로세스로 분석하였으며. 초점거리는 $62.2{\mu}m$이었다. 본 제작방법은 일반적인 사진식각 공정을 이용한 마이크로렌즈 제작보다 간단하면서도 저렴한 비용으로 제작이 가능하다. 또한 곡률반경의 조절이 용이하고, 보다 정밀하며 다양한 마이크로렌즈 어레이를 구현할 수 있다.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2003년도 추계학술대회논문집
• /
• pp.76-79
• /
• 2003

Glass molding is an advantageous method to manufacture glass micro optical components. However, it is difficult to make tungsten carbide core for glass molded micro optics way. We have developed novel method to fabricate tungsten carbide core for glass molding of glass micro optical components. Silicon masters were fabricated by micro machining. Tungsten Carbide cores were fabricated by forming, sintering and coating. Finally we fabricated glass molded V-groove with pitch of 192$\mu\textrm{m}$ and glass microlens way with lens diameter of 36∼225$\mu\textrm{m}$ by the present method.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.199-199
• /
• 2009

Recently, polymeric microlens arrays have become important elements in many applications. Microlens arrays have been used to enhance luminance efficiency and luminance power efficiency of light-emitting diodes (LEDs) and organic LEDs. Many processes for fabrication of microlens array are studied. Though the MLA has been fabricated by electroformed mold, LIGA process and reflow method, these methods were required masks, multiple process steps and post processing. In this paper, we proposed rapid and direct UV laser direct fabrication process using colorless liquid photopolymer, NOA60 for polarization activated microlens. The microlens arrays are formed on the NOA60 on glass, after the focused laser energy was irradiated to the material. The diameter of MLA was varied from 42 to 88 ${\mu}m$, and the height from 0.9 to 1.6 ${\mu}m$. The MLA fabricated using NOA60 shows more then 85% transmittance as well as good hardness for optical module.

• 소성∙가공
• /
• 제15권1호
• /
• pp.34-41
• /
• 2006

Microlens arrays were fabricated by a modified LIGA process composed of the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, both hot embossing and microinjection molding processes have been successfully utilized with the fabricated mold insert. Replicated microlenses showed very good surface roughness with the order of 1 nm. The focal lengths of the injection molded microlenses were successfully estimated theoretically and also measured experimentally.

• 한국소성가공학회:학술대회논문집
• /
• 한국소성가공학회 2005년도 금형가공,미세가공,플라스틱가공 공동 심포지엄
• /
• pp.23-28
• /
• 2005

Microlens arrays were fabricated using a modified LIGA process based on the exposure of a PMMA (Polymethylmethacrylate) sheet to deep x-rays and subsequent thermal treatment. A successful modeling and analyses for microlens formation were presented according to the experimental procedure. A nickel mold insert was fabricated by the nickel electroforming process on the PMMA microlens arrays fabricated by the modified LIGA process. For the replication of microlens arrays having various diameters with different foci on the same substrate, the hot embossing and the microinjection molding processes have been successfully utilized with the fabricated mold insert. Fabricated microlenses showed good surface roughness than the mold insert. The focal lengths of the injection molded microlenses were successfully measured experimentally and also estimated theoretically.