Microprism Array Research Articles

Solvent-infiltration imprint lithography: a novel method to prepare large area poly(3-hexylthiophene) micro/nano-patterns

A new method is developed in this work to fabricate large area poly(3-hexylthiophene) (P3HT) micro/nano-patterns. The method is based on solvent-infiltration imprint lithography (SIIL). P3HT micro/nano-patterns, including micro-prism arrays, nano-grating and nano-hole arrays, have been successfully prepared with features ranging from 400 nm to 3 μm. The regularity of the patterns was studied by SEM and the morphology of the pattern surfaces was investigated by atomic force microscope (AFM). The solidification mechanism of this method is based on solvent infiltration instead of external UV or heat to form the polymer pattern. This mechanism makes SIIL more universal, of lower cost than hard-mold imprint lithography, and more efficient than capillary force based lithography since high glass transition temperature (Tg) polymers or even polymer/nano-particle blends can be patterned quickly. Polymer solar cells with nano-hole arrays and nano-grating are prepared using SIIL, respectively, and the power conversion efficiency is improved compared with traditional film-structure polymer solar cells.

Development of a 3D artificial compound eye

In this research paper, in a major departure from conventional 2D micromachining processes, design and fabrication of a 3D compound eye system consisting of a 3D microprism array, an aperture array, and a microlens array were investigated. Specifically, the 3D microprism array on a curved surface was designed to steer the incident light from all three dimensions to a 2D plane for image formation. For each microprism, there is a corresponding microlens to focus the refracted light on the image plane. An aperture array was also implemented between the microprism array and the microlens array to eliminate cross-talk among the neighboring channels. In this system, 601 individual micro-assemblies consisting of microprisms and microlenses were constructed in a 20 mm diameter area. In this configuration, the maximum light deviation angle was determined to be 18.43 degrees. This research demonstrated an innovative and integrated approach to fabricating true 3D micro and meso scale optical structures. This work also validated the feasibility of using ultraprecision machining process for 3D microoptical device fabrication. The technology demonstrated in this research has high potentials in optical sensing, vision research and many other optical and photonic applications.

Design of a novel symmetric microprism array for dual-view display

Abstract This research is to design a microprism array optical film which can be attached on 2.2-in. liquid crystal displays. The sizes of the base width of the microprism and the sub-pixel of the panel were corresponding. After the selection of the appropriate vertex angles, two images could be delivered to left and right viewing zones of the panel. This research also used flexible material polydimethylsiloxane (PDMS) with high transmission as the optical film. Besides, it utilized LightTools software to process the ray tracing, which obtained the left and the right images, respectively, delivered to the visual angles of −47.5 to +16.5° and −11.5 to +48.5°. Slight crosstalk only located within −31.5 to −25.5° and +28.5 to +30.5°, respectively. It shows that the microprism sheet can actually make general panels have dual-view display function.

Transmissive beam steering through electrowetting microprism arrays

Reported is a numerical calculation of near-field and far-field intensities for two electrowetting microprism designs. This includes an investigation of one-dimensional, two-dimensional, and bi-prism pixellated arrays. The diffraction efficiency of an incident Gaussian beam is investigated. Far-field deflection angles are extended to more than 10°. For the phased arrays the diffraction angles are discrete and the angles between the diffraction peaks can be covered by applying a tilted phase to the input field.

Holographic Fabrication of Microstructures with Internal Nanopatterns Using Microprism Arrays

Holographic Fabrication of Microstructures with Internal Nanopatterns Using Microprism Arrays

Holographic Fabrication of Microstructures with Internal Nanopatterns Using Microprism Arrays

Holographic Fabrication of Microstructures with Internal Nanopatterns Using Microprism Arrays

Optics system design applying a micro-prism array of a single lens stereo image pair

In this study we apply a micro-prism array technique to enable a single lens CCD to capture a stereo image for the simulation of double lens vision. A micro-prism array plate serves as the basis for design, which also improves the lightweight and portability of the overall system in addition to lowering the mass-production costs. Most important of all, this design possesses the characteristics of integration compatibility between general-purpose and video camera.

Well-aligned ZnO microprism arrays with umbrella-like tips: Low-temperature preparation, structure and UV photoluminescence improvement

Catalyst-free, low-temperature (430 °C), high-density, well-aligned, single-crystalline zinc oxide (ZnO) microprism (ZMP) arrays have been synthesized over the entire c-ZnO/poly-Zn-coated Si substrates by simple thermal evaporation of Zn powder. Specially, the microprisms obtained possess hexagonal umbrella-like tips on which vertical thin ZnO nanowires grow. The growth mechanism of a three-stage thermodynamic process was discussed. Photoluminescence spectra show a strong ultraviolet (UV) emission enhancement of the ZMPs after H + (hydrogen ions) implantation. This kind of special ZnO microstructure may find potential applications in field emission, UV laser emission devices, multifunctional microdevices and highly integrated multichannel nano-optoelectronic devices.

Development of a monolithic total internal reflection-based biochip utilizing a microprism array for fluorescence sensing

This paper proposes a monolithic integration method to fabricate a total-internal-reflection (TIR) based biosensor for fluorescence sensing. The monolithic TIR-based biosensor integrates a microfluidic chamber, polymer-based optics and planar waveguides into a high-throughput platform. The polymer-based optics, fabricated by SU-8 resist, include cylindrical microlenses and a microprism array for effectively conducting the excitation light into the planar waveguide. Two kinds of substrate materials, namely quartz and SU-8 resist, are used to fabricate the planar optical waveguides for efficiency comparison. To fabricate the microprism array, a technology employing glycerol-compensated oblique exposure is employed, and microprism arrays with inclined surface angles from 25° to 35° on the planar optical waveguide have been successfully fabricated. Multiple total internal reflection spots can be observed through this monolithically integrated optical system simultaneously. The real-time Brownian motion of fluorescent microspheres excited by the evanescent wave under this system is captured for motion analysis. The results demonstrate the feasibility of this system on the study of nanoscale phenomena. The unique fabrication and integration aspects of the monolithic biosensor including on-chip micro-optics simplify current TIR optical configurations and could potentially be integrated into a lab-on-a-chip microsystem.

Numerical method to predict and fabricate aspherical microlens arrays using 248-nm excimer laser ablation

A method of numerical simulations is used to predict the pro- file of a 3-D aspherical microlens array. Based on the simulated results, the desired micro-optical lens profile is obtained through excimer laser ablation. The simulation method applied in the excimer laser ablation can significantly reduce the quantity of microablation experiments. The ab- lated microstructures with surface average roughness of Ra,20 nm are successfully achieved for micro-optical components. The excimer laser ablation parameters include laser fluence, shot number, workstation scanning velocity, and repetition rate. Various profiles of microlens and microprism arrays with different dimensions can utilize numerical simu- lation and form desired geometries by laser ablation. © 2004 Society of

Design and fabrication of polymeric micro-optical components using excimer laser ablation

Numerical simulation was used to predict the profile of a three-dimensional aspherical microlens and a microprism array. Based on the simulated results, the desired micro-optical lens profile was obtained using excimer laser ablated polyimide. The simulation method applied to excimer laser ablation can significantly reduce the quantity of microablation experiments. Ablated microstructures with surface roughness Ra < 20 nm were successfully achieved for micro-optical components. The excimer laser ablation parameters included laser fluence, shot number, workstation velocity, and repetition rate. Numerical simulation can be applied to predict various profiles of microlens and microprism arrays with different dimensions, the desired geometries being formed by laser ablation.

A microprism array as shearing device for speckle shearing interferometry

In most speckle shearing interferometers image shearing is performed by means of a Michelson interferometer or by means of a wedge prism covering half of the aperture of the camera objective. We present a speckle shearing interferometer which utilizes a microprism array for this purpose. It is placed between the test specimen and the camera. In comparision with a wedge prism it exhibits some advantages: it needs no exact alignment, it works with any camera lens, the shearing distance and direction of shearing can be easily changed by changing position (resp. angular orientation) of the element. Phase stepping for computer evaluation of the speckle shearing interferograms is performed by the translation of the shearing element. A special translation stage was developed. Experimental results are presented. The interferometer is suited for microcomponent and microsystem testing.

Chemical cleaving method of relief microstructure formation on dichromated gelatin

A chemical cleaving method to improve the resolution of relief modulation in dichromated gelatin is presented. The process (which uses hydroxylamine) yields higher relief resolution and better profile fidelity than a process that uses the enzyme trypsin because it has many fewer cleaving sites. Experiments prove that relief modulation can produce a resolution of as much as 500 lines/mm. With a projection exposure system, a microprism array with a 30-mum-wide, 0.8-mum-high cell is fabricated by this method. A method for forming a continuous relief on dichromated gelatin is also discussed.

High-efficiency micro-optical color filter for liquid-crystal projection system applications

High-efficiency color filters composed of a microprism array, optical interference color filters, and a microlens array light compressor were developed to increase the optical throughput of liquid-crystal projection systems. The new devices utilize the energy of whole spectra by taking full advantage of a light compressor and interference dichroic filters to distribute the energy of spectra to the respective color pixel area. Thus high-efficiency micro-optical color filters allow efficient utilization of the energy of incident light and maximize the optical throughput of the projection system.

Optical beam direction compensating system for board-to-board free space optical interconnection in high-capacity ATM switch

In interconnections between bookshelf-assembled asynchronous transfer mode (ATM) switch boards, a large number of micro-optical signal beams can be optically interconnected by a beam direction compensating system using a vertical cavity surface emitting laser, an x-y beam positioning sensor and a beam deflector made of an adjustable liquid prism. This beam direction compensating system can suppress the decrease in coupling efficiency between transmitters and receivers to no more than 15%, even if boards are inserted and extracted repeatedly, and are shocked repeatedly at a high intensity of 100 G. The compensation is very fast (20 ms). Furthermore, various optical interconnections necessary for ATM switching networks can be achieved by beam deflectors of a liquid crystal microprism array. In this preliminary study, we fabricate no more than eight-channel optical interconnections. However, since one surface emitting laser diode can have many channels in a small area (64 channels per 4 mm/sup 2/) and the aperture of this adjustable liquid prism is wide (28 mm in diameter) and uniform, a huge number of optical interconnection channels is possible using this system.

Relationship between optical and electrical properties of liquid-crystal optical devices

It is shown that the relationship between capacitance and refractive index is linear for liquid-crystal optical devices, such as liquid-crystal Fabry-Perot interferometer filters and liquid-crystal microprism arrays. A linearizing circuit that compensates for the nonlinear properties of liquid-crystal optical devices is made, in which capacitance instead of applied voltage is monitored. It can also directly display the value of the transmission peak wavelength or the def lection angle.

Free-space optical interconnections with liquid-crystal microprism arrays

Liquid-crystal microprism arrays are shown to be useful for providing electrically controlled alignment of optical beams and fixed various free-space optical interconnections. They can deflect closely spaced micro-optical beams individually to any position with high transmittance (95%), high deflection angle (~10°), and low voltage (<2.8 V(rms)). Various fixed optical interconnections can be made simply by changes in the voltages applied to the microprism.

Planar optical implementation of crossover interconnects

We propose a planar optical configuration for implementation of crossover interconnects. The planar overlay allows two-dimensional pixel arrays located on a wafer-scale integrated circuit to be interconnected in a compact and vibrationally robust configuration. By using an acute-angle microprism array with apex angles of 70.52 deg fabricated on a silicon substrate, we show the experimental result of the crossover interconnections. Some practical limits of the planar optical crossover interconnections are also discussed.

Array of Brewster telescopes

Brewster telescopes are useful for anamorphic image formation or for anamorphic beam compression. With an array of micro-Brewster telescopes a wide uniform beam can be compressed into many beams of a smaller diameter. Thus arrays of microprisms might form an array of micro-Brewster telescopes, which can be used as array illuminator.