Mushroom microlenses: optimized microlenses by reflow of multiple layers of photoresist

Heremans, Paul; Genoe, Jan; Kujik, M.; Vounckx, Roger; Borghs, Gustaaf

doi:10.1109/68.623265

Cited by 45 publications

(21 citation statements)

References 2 publications

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“…The most recent example of this technology is the mushroom-shaped photoresist microlens. 4 Here, a highly directional beam was obtained but the efficiency of the microlens LED was only a factor of 2 larger than the original device. Presumably, the efficiency enhancement is limited by the poor index match of the photoresist (nϷ1.6) to the semiconductor.…”

Section: Efficient Directional Spontaneous Emission From An Ingaas/inmentioning

confidence: 97%

Efficient directional spontaneous emission from an InGaAs/InP heterostructure with an integral parabolic reflector

Gfroerer

Cornell

Wanlass

1998

Journal of Applied Physics

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In order to increase the radiative efficiency and directivity of spontaneous emission from a lattice-matched InGaAs/InP heterostructure, we have polished the substrate into a parabolic reflector. We combine optical and thermal measurements to obtain the absolute external efficiency over a wide range of carrier densities. Using a simple model, the measurement is used to determine interface, radiative, and Auger recombination rates in the active material. At the optimal density, the quantum efficiency exceeds 60% at room temperature. The divergence of the emitted light is less than 20°. In fact, the beam profile is dominated by a 6° wide lobe that can be swept across the field of emission by changing the excitation position. This suggests a way to create an all-electronic scanned light beam.

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Section: Efficient Directional Spontaneous Emission From An Ingaas/inmentioning

confidence: 97%

Efficient directional spontaneous emission from an InGaAs/InP heterostructure with an integral parabolic reflector

Gfroerer

Cornell

Wanlass

1998

Journal of Applied Physics

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“…For instance, the UV-curable polymer was dispensed and cured to form the microlens on chip [3,4]. The photoresist reflow [5], and the electrostatic force shape modulation [6] have also been reported to form the microlens of various shape. So far the available 3D lens shapes are still limited by the process technology, for example the photolithography on a highly structured substrate surface [7].…”

Section: Introductionmentioning

confidence: 99%

Formation and curvature tuning of micro lens using surface tension and hydraulic pressure assisted molding process

Hsu

Lee

Fang

2013

2013 IEEE 26th International Conference on Micro Electro Mechanical Systems (MEMS)

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This study presents a novel concept for the formation of curvature micro lens and the lens-curvature tuning using the hydraulic pressure and surface tension assisted molding process. The liquid UV-curable polymer is defined by hydraulic pressure, surface tension, and molding, and then solidified by UV-light to form the micro-lens. Merits of the process technology are: (1) initial lens curvatures defined by the polymer volume and surface tension, (2) final lens curvature is tuned by the hydraulic pressure, and (3) optical pattern (Fresnel zone) can be defined by molding. In applications, the biconvex, biconcave, and convex-concave lens, and the curved Fresnel lens are demonstrated. The lens radius of curvature R c is varying from -0.58mm to 1.5mm. The integration of micro-lens with magnet holder for actuation is also demonstrated.

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“…Among photoelectric components, microlens are widely used in areas such as fiber focusing, laser transducer, LD aligner with diode arrays, and light storage and auto‐focusing system of digital cameras. During recent years, microlens can be made of different materials, such as silicon,1 gallium arsenide,2 sapphire,3 diamond,4 silicon dioxide,5 photo‐resist,6 and polymer 7…”

Section: Introductionmentioning

confidence: 99%

Applying magnetic soft mold imprint technology with ultraviolet light‐emitting‐diode array on the fabrication of microlens arrays

Weng

Yang

2011

Polymers for Advanced Techs

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This study proposed a novel technology, which uses exposed technology with ultraviolet light‐emitting‐diode (UV‐LED) arrays and the polydimethylsiloxane (PDMS) magnetic flexible soft mold imprint technology, to develop exposed equipments with UV‐LED arrays. This study used magnetic soft mold imprint technology to replicate the structure of microlens, providing a more effective alternative for imprint technology and application. The measurement results showed that PDMS with magnetic iron powder can precisely cast mold to replicate the structures of microlens. Electromagnetic plates were used to control even imprinting with magnetic force, in order to fill the mold of micro‐structure of the photo‐resist. Magnetic iron powder was added to PDMS to produce composite material, which can effectively avoid the transformation of pure PDMS during soft mold imprinting, and increase mechanical strength. Magnetic PDMS soft mold is easy to make, and the casting time is short, so that costs can be effectively reduced. Also with advantages of less free energy on its surface, and unlikely to adhere to the photo‐resist during imprinting, it can be combined with electromagnetic plates evenly to control the magnetic soft mold. This imprinting technology is a big advantage to the production process of micro‐structures during imprinting. Copyright © 2009 John Wiley & Sons, Ltd.

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Mushroom microlenses: optimized microlenses by reflow of multiple layers of photoresist

Cited by 45 publications

References 2 publications

Efficient directional spontaneous emission from an InGaAs/InP heterostructure with an integral parabolic reflector

Efficient directional spontaneous emission from an InGaAs/InP heterostructure with an integral parabolic reflector

Formation and curvature tuning of micro lens using surface tension and hydraulic pressure assisted molding process

Applying magnetic soft mold imprint technology with ultraviolet light‐emitting‐diode array on the fabrication of microlens arrays

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