KEYWORDS: 3D printing, Microfluidics, Computer aided design, Stereolithography, Interfaces, Lab on a chip, Digital Light Processing, Ultraviolet radiation
While there is great interest in 3D printing for microfluidic device fabrication, the challenge has been to achieve feature sizes that are in the truly microfluidic regime (<100 μm). The fundamental problem is that commercial tools and materials, which excel in many other application areas, have not been developed to address the unique needs of microfluidic device fabrication. Consequently, we have created our own stereolithographic 3D printer and materials that are specifically tailored to meet these needs. We review our recent work and show that flow channels as small as 18 µm x 20 µm can be reliably fabricated, as well as compact active elements such as valves and pumps. With these capabilities, we demonstrate highly integrated 3D printed microfluidic devices that measure only a few millimeters on a side, and that integrate separate chip-to-world interfaces through high density interconnects (up to 88 interconnects per square mm) that are directly 3D printed as part of a device chip. These advances open the door to 3D printing as a replacement for expensive cleanroom fabrication processes, with the additional advantage of fast (30 minute), parallel fabrication of many devices in a single print run due to their small size.
KEYWORDS: Microfluidics, CMOS sensors, Signal to noise ratio, Sensors, Microfluidic imaging, Imaging systems, Amplifiers, System integration, Signal detection, Integrated optics
We demonstrate a hybrid “package-less” polydimethylsiloxane (PDMS)–complementary metal–oxide–semiconductor (CMOS)-FR4 system for contact imaging. The system embeds the CMOS image sensor directly in a PDMS layer instead of the standard chip package to support microfluidic structures much larger and more complex than those in prior art. The CMOS/PDMS layer is self-aligned to form a continuous, flat surface to provide structural support for upper microfluidic layers. The system consists of five layers of PDMS implementing fluid channels, valves, chambers, and inlets/outlets. A custom CMOS image sensor with integrated signal conditioning circuits directly captures light from sample fluid for high optical collection efficiency. Owing to the flexibility afforded by the integration process, the system demonstrates, for the first time, integrated valves in contact imaging. Moreover, we present the first direct comparison of the optical performance of a CMOS image sensor and a photomultiplier tube (PMT) in identical contact-imaging conditions. Measurements show that our CMOS sensor achieves 17 dB better signal-to-noise ratio (SNR) compared with a commercial PMT across a broad range of integration times, with a maximum SNR of 47 dB. Chemiluminescent testing successfully shows signal detection for different analyte concentrations and integration times. The contact-imaging system demonstrates a detection limit of 25 μM of a 9,10-diphenylanthracene-based solution.
The use of fluorescence in microfluidic optical biodetection requires materials with low-background fluorescence to avoid influencing the desired optical signal with spurious light emission. For the same reason, spurious light emission from galvanoluminescence (GL) should be avoided when fluorescence is used in dielectrophoresis (DEP)-based biosensors. Use of non-noble metal electrodes such as indium tin oxide (ITO) in DEP devices is therefore a concern. We evaluate GL in the context of conditions typical of DEP devices. We experimentally show that use of ITO can result in GL. We also show that GL can be avoided, even with metals that demonstrate strong GL such as Al, by proper selection of operating frequency, which can be determined by measuring the impedance spectrum of the DEP device. In addition, we demonstrate that GL results in broadband emission for all of the salt solutions tested. Broadband emission implies that at least some of the light will pass through typical fluorescence filters if a device exhibits GL. We also show that Ni and Cr electrodes do not exhibit GL and may therefore be suitable as low-cost DEP electrodes.
We investigate bonding polydimethylsiloxane (PDMS) to silicon using a thin (∼2 μm) intermediate adhesive layer stamped onto a PDMS piece prior to bonding. In particular, we compare as adhesive layers Sylgard 184 and 182 curing agents and a UV curable adhesive (NOA 75). We examine the effect of both curing temperature and duration on curing agent bond strength. Bond strengths for the different adhesives are determined by measuring the average burst pressure at a PDMS-silicon interface using a PDMS test design. We find that Sylgard 184 curing agent gives the highest bond strength with burst pressure of 700 kPa or more for curing at either 60°C for 3 h, 70°C for 30 min, or 90°C for 20 min. Curing at room temperature takes substantially more time with an average burst pressure of 433 and 555 kPa for curing times of 16 and 27 h, respectively. In comparison, Sylgard 182 curing agent takes 32 h at room temperature to achieve a burst pressure of 289 kPa, while NOA 75 with a 50°C 12 h post-UV exposure bake yields a burst pressure of 125 kPa.
We report the integration of a nanomechanical sensor consisting of 16 silicon microcantilevers and polydimethylsiloxane
(PDMS) microfluidics. With our recently developed in-plane photonic transduction method we routinely achieve
microcantilever transduction responsivities in the range of 0.5-1.1 μm-1, which is comparable to the best reported for the
laser reflection readout method used in atomic force microscopy (AFM). Prior work has established that differential
surface stress as low as 0.23 mN/m is readily measurable with our arrays. In this paper we show biotin-streptavidin
sensing with a differential surface stress of ~2.3 mN/m as a first step toward characterizing integrated microcantilever
array/microfluidic sensors.
We demonstrate a compact trench-based silicon-on-insulator (SOI) rib waveguide ring resonator comprised of trench-based bends and splitters. It has a perimeter of 50 µm and occupies an area of only 25×25 µm. The measured free spectral range (FSR) is 13.2 nm, which the largest reported for an SOI rib waveguide ring resonator. The measured FSR, full width at half maximum, and quality factor match reasonably well with analytical calculations. Further calculation shows that a FSR of 50.8 nm is achievable for an SOI rib waveguide ring resonator with a perimeter of 15 µm.
A fabrication process for PFCB waveguide air-trench bends with scanning electron microscope (SEM)-based electron
beam lithography (EBL) and autoalignment has been developed and high efficiency air-trench bends (97.2% for TE
polarization and 96.2% for TM polarization) have been demonstrated. We have successfully developed a high aspect
ratio (18:1) anisotropic PFCB etch using a CO/O2 etch chemistry in an inductively coupled plasma reactive ion etcher
(ICP RIE) for PFCB waveguide air-trench splitter fabrication. The fabricated splitters show a 90.1% overall efficiency
and ~ 85-to-15 (85:15) splitting ratio for 950 nm wide splitter trench, which closely matches 2D-FDTD simulation
results. Using air-trench bends, an ultracompact PFCB arrayed waveguide grating (AWG) 8 x 8 wavelength
demultiplexer for Wavelength Division Multiplexing (WDM) application had been designed. Compared to a
conventional AWG in the same material system, the air-trench bend AWG reduces the area required by a factor of 20.
Compact ring resonators using these splitters and bends has been designed and fabrication and improvements are
currently underway.
Microcantilevers show significant promise in sensing minute quantities of chemical and biological analytes in vapor and
liquid media. Much of the reported work on microcantilever sensors has made use of single functionalized
microcantilevers, usually derived from commercially available atomic force microscope (AFM) cantilevers. However,
arrays with hundreds to thousands of microcantilevers on a single chip are required to create sophisticated, broad
spectrum chemical and biological sensors in which individual microcantilevers have different bio- or chemoselective
coatings. Unfortunately, the most sensitive microcantilever readout mechanisms (such as laser beam reflection as used in
atomic force microscopy) are not readily scalable to large arrays. We therefore introduce a new microcantilever
transduction mechanism for silicon-on-insulator (SOI) microcantilevers that is designed to scale to large arrays while
maintaining a very compact form factor and high sensitivity. This mechanism is based on in-plane photonic transduction
of microcantilever deflection in which the microcantilever itself forms a single mode rib waveguide. Light from the end
of the microcantilever is directed across a small gap to an asymmetric receiving waveguide with two outputs that enables
differential detection of microcantilever deflection. Initial noise and optical power budget calculations indicate that
deflection sensitivities in the 10's of picometer range should be achievable.
Silicon-on-insulator (SOI) is a widely recognized as a very promising material for high-index integrated photonic chips
because of its compatibility with complementary metal oxide semiconductor (CMOS) technologies. One challenge in
integrating many photonic devices on a single chip is to realize compact waveguide bends and splitters, particularly for
rib waveguide geometries. We report compact SOI rib waveguide 90° bends and splitters with SU8-filled trenches based
on total internal reflection (TIR). We use the two-dimensional finite difference time domain (2D-FDTD) method to
numerically calculate bend and splitter efficiencies. The maximum bend efficiency is 98.0%. The splitter efficiency is
49.0% for transmission and 48.9% for reflection with an 80 nm wide SU8-filled trench. Electron beam lithography
(EBL) is used to accurately position the trench interface relative to the waveguides and to pattern the 80 nm wide trench.
Inductively coupled plasma reactive ion etching (ICP RIE) is used to achieve a vertical sidewall. For fabricated bends
the measured bend loss is 0.32±0.02 dB/bend (93% bend efficiency) for TE polarization at a wavelength of 1.55 microns,
which is the lowest SOI rib waveguide 90° bend loss reported in literature. The initial measured splitter efficiency is
54.6% for transmission and 29.2% for reflection. This can be improved by avoiding defects in fabricated structures.
We propose an integrated waveguide depolarizer for use in interferometric fiber optic gyroscopes (IFOGs) with single-mode fiber coils. The integrated waveguide depolarizer is based on a Mach-Zender interferometer with polarizing beamsplitters. A waveguide polarizing beamsplitter is designed using multiple air trench structures oriented at the Brewster angle. We also analyze the effect of component imperfections on the degree of polarization achievable with an integrated waveguide depolarizer.
We discuss the design of a compact ring resonator (RR) and Mach-Zehnder interferometer (MZI) in a low-refractive-index-contrast waveguide material system through the use of air trenches. A narrow air trench at the intersection of one input and two output waveguides can function as a high-efficiency splitter, while wider air trenches operate as waveguide bends. We first discuss the design of individual splitters and bends and then show how they can be used to realize a compact MZI and RR. The RR has a footprint of only 70×100 µm, and its optical efficiency at the drop wavelengths is 86%. The free spectral range and full width at half maximum are 7.2 and 0.5 nm, while the Q factor is >3,000. The MZI occupies only 165×130 µm, and its calculated optical efficiency is 90%.
Compact waveguide bends and splitters are important components to enable dense integration of many functions on a single photonic chip. A common approach is to use a waveguide material system in which a large refractive index contrast between the core and clad materials is available. This permits a small bend radius to be used while still achieving high optical efficiency for the bend. However, such material systems generally have higher propagation loss than is possible with low refractive index contrast material systems such as silica. In this presentation we examine an approach to make the bend size essentially independent of the core/clad refractive index contrast using total internal reflection from a planar interface. We show through both 2D and 3D finite difference time domain (FDTD) simulation that very high bend efficiencies are possible when the correct bend design principles are adhered to. We illustrate this in practice with single air interface bends (SAIBs) in a PFCB material system with approximately 1% refractive index contrast. We experimentally demonstrate 45 degree bends with 0.3 dB loss per bend, and discuss the effects of fabrication issues such as misalignment, etch undercut, and etch roughness.
High efficiency small-area waveguide bends and splitters for perfluorocyclobutane (PFCB) copolymer materials have been designed with air trench structures (ATSs). An air trench at the intersection of one input and two output waveguides can function as a high efficiency splitter. High efficiency small-area waveguide bends are achieved by placing ATSs at the waveguide bend corners and operate through total internal reflection (TIR). In this paper we discuss bends and splitters that are designed specifically for constructing a ring resonator and a Mach-Zender interferometer. Two dimensional (2-D) finite difference time domain (FDTD) analysis has been used for design. In order to further examine the performance of realistic small-area air trench bend structures, we have also employed three dimensional (3-D) FDTD. From 3-D FDTD simulation results, we find that the 2-D designs are representative of actual devices. By combining small-area air trench bends and splitters, we show how a compact ring resonator can be realized. Simulation results show attractive properties for the proposed ring resonator design. Preliminary ATS etch results of PFCB with CO and O2 shows the possibility of fabricating the proposed devices.
Dramatic reductions in the size of waveguide bends for materials with low core/clad refractive index contrast can be achieved with single air interface bends (SAIBs) based on total internal reflection. However, high optical efficiency for such bends requires vertical interfaces with low surface roughness. In this presentation we report the development of a highly anisotropic etch for perfluorocyclobutane (PFCB) waveguide structures. We examine the use of inductively coupled plasma reactive ion etching (ICP RIE) based on both oxygen/helium and carbon dioxide/helium etch chemistries to achieve the desired interface quality for high efficiency waveguide bends.
The ability to make small-area bends and splitters in low index contrast waveguide materials is a critical enabler to realize densely integrated planar lightwave circuits (PLCs) in such materials. We discuss two approaches, the first based on photonic crystal (PhC) structures of limited spatial extent and the second on single air trenches. In each case, PhC or air trench regions are used to augment conventional waveguides (CWGs) to permit drastic reductions in overall device size while preserving the traditional advantages of CWGs such as straightforward design for single mode operation, low propagation loss, low fiber coupling loss, low dispersion, and mature microfabrication processes. We show how these approaches can be used to realize example devices having a very small footprint, including Mach-Zender interferometers and ring resonators.
We previously proposed the hybrid integration of photonic crystals (PhCs) and conventional index-guided waveguides (CWGs) as a potentially attractive method of realizing compact waveguide elements for large-scale planar lightwave circuits (PLCs). We now examine 90-deg bends and beamsplitters in PhC/CWG structures in which the waveguide core has a high refractive index (3.25) and yet a low refractive index contrast (1.54%) with the clad material. A PhC structure composed of a triangular or square array of air holes is placed at the intersection of input and output waveguides to obtain high efficiency 90-deg bends. We find that diffraction from the boundary of the PhC region with CWG limits the optical efficiency of the bend. To overcome this we use a rigorous design tool based on a microgenetic algorithm (µGA) and a finite difference time domain (FDTD) method to optimize the boundary layer to suppress the unwanted diffraction. We find that this approach yields improvements in the bend efficiency at a wavelength of 1.55 µm from 56.2 to 92.5% (for a triangular PhC structure, TE polarization) and from 72.0 to 97.4% (square PhC structure, TM polarization).
Hybrid photonic crystal (PhC) and conventional waveguide (CWG) structures have been proposed to achieve ultracompact waveguide bends and splitters with very high efficiency (>99.0%). Such elements are enablers to realize large scale planar lightwave circuits (PLCs) with low index contrast waveguide materials such as silica and polymers. In this paper, we first discuss high efficiency 90 degree bends and splitters and then show how these can be used to create compact ring resonators. These in turn can be used as building blocks for add/drop filters, band pass filters, wavelength division multi-/demultiplexers, and all optical switches.
We have proposed the hybrid integration of photonic crystals (PhCs) and conventional index-guided waveguides (CWGs) as a potentially attractive method of realizing compact waveguide elements for large-scale planar lightwave circuits (PLCs). In this paper we briefly review the properties of PhC/CWG 90° bends in low index, low index contrast waveguides and then extend them to waveguides with high index and low index contrast. We find that diffraction from the boundary of the PhC region limits the optical efficiency of the bend. To overcome this we use a rigorous design tool based on a micro-genetic algorithm (microGA) and a finite difference time domain (FDTD) method to optimize the boundary layer to suppress the unwanted diffraction. We find that this approach yields an improvement in the bend efficiency for light at 1.55 micron from 80% to 95%.
We discuss the use of multiple layer air trench and silicon strip structures to realize high efficiency 90° bends for low index contrast waveguides. We use a micro-genetic algorithm (mGA) coupled with a 2-D finite difference time domain method to perform rigorous electromagnetic optimization of multi-layer structures for single mode waveguides. We find that a 3-layer air trench structure can be designed for a 90° waveguide bend that exhibits 97.2% efficiency for TM polarized light at a wavelength of 1.55 μm. We are also able to design five- and six-layer silicon strip bends that have high efficiency for both TE and TM polarizations. For example, simulation results for a six-layer design show 95.2% and 97.2% for TE and TM polarizations, respectively. Moreover, the bend efficiency for each polarization state is greater than 90% over a broad wavelength range (1.5 μm to 1.7 μm).
This paper reports the development of the first Liquid Crystal Adaptive Lens (LCAL) with circular electrodes for imaging application. LCAL is an electro-optical device using a set of electrodes to grade the refractive index across its aperture. The principle of liquid crystal adaptive lens is briefly discussed. The special advantages and challenges in using circular electrodes are addressed. Numerical simulation is performed to predict the imaging performance. A prototype of LCAL was designed according to the requirements for application in a microscope imaging system with a diameter of 7.86 mm and a focal length adjustable from 0.2m to infinity. The structure of the LCAL with circular electrodes includes the top ITO ring electrodes and the connecting wires, insulating layer, ITO plugs, and the bottom ITO conducting wires. This prototype was fabricated on a glass substrate by using micro-fabrication process. The focusing performance of the LCAL with circular electrodes was presented. The experimental results agree well with the simulation results. The imaging experiment of LCAL is performed when LCAL focal length is 1m, 0.38m and 0.2m under incoherent source. The resolution of the images formed by LCAL combined with a fixed lens is indistinguishable from that of the image formed only by a fixed lens, while the contrast is lower.
Perfluorocyclobutyl (PFCB) polymers and copolymers enjoy a unique combination of properties well suited for optical applications such as high temperature stability, precisely controlled refractive index, low moisture absorption, excellent melt and solution processability, a variable thermoptic coefficient, and low transmission loss at 1300 and 1550 nm. Copolymerization reactions offer tailored thermal and optical properties by simple choice of comonomer. PFCB copolymers can be solution or melt microfabricated via standard methods and can also be processed via micro-transfer molding in photolithographically generated features. Reliable molding of polymer waveguides offers significant potential to reduce photonic integrated circuit (PIC) fabrication costs and enable the realization of compact, integrated subsystems for a variety of applications. Copolymerization chemistry, thermoptic measurements, and initial results on the first micro-transfer molded waveguide structures are presented.
This paper describes in detail the historical development of the ICVision system which is based on the partial pixel architecture. The partial pixel architecture allows the realization of three-dimensional (3-D) displays that are functionally equivalent to realtime holographic stereograms. As such, this architecture permits the simultaneous presentation of multiple stereoscopic images so that motion parallax is discernible in the resultant 3-D scene. The key innovation of the architecture is that each pixel is subdivided into partial pixels, which in turn can be implemented as individual diffraction gratings.
In addition to describing the partial pixel architecture, this paper presents the details of several demonstration devices including a static device developed for image evaluation, and two dynamic systems based on liquid crystal devices.
The liquid crystal adaptive lens (LCAL) is an electro-optical device using a set of electrodes to grade the refractive index across its aperture. We report initial efforts at developing an LCAL using circular electrodes to provide a simpler architecture and faster response than previous devices based on linear electrodes. A Fresnel lens phase profile is applied to yield a lens with a useful F-number. Numerical simulation is developed to study the aberration of the LCAL and predict its performance with a circular electrode geometry. The LCAL is designed with a set of high density electrodes in the conductive ladder meshing configuration which results in a small number of externally controlled electrodes. A new feedback auto-focusing system based on LabVIEW software has been developed to optimize control output voltages using signals from a CID camera. The application of LCAL in microscope imaging systems for focus adjustment without lens motion is described. A prototype LCAL is being designed that has a 7.86 mm diameter aperture and a focal length adjustable from 0.38 m to infinity. It is fabricated on a glass substrate with two layers of transparent electrodes, insulating layers, and vias to connect the two conducting layers. The special fabrication challenges involved will be reviewed.
An attractive approach to realizing a real-time imaging polarimeter is to integrate an array of polarization- sensitive filers directly onto the focal plane array. This has the advantage of allowing all of the requisite polarization data to be acquired within each image frame. In this paper we discuss the design, fabrication, and performance of a diffractive optical element (DOE) that fulfills this requirement. The DOE consists of an array of broadband form birefringent quarter-wave plates and wire grid polarizers which are designed to allow the measurement of all four Stokes vector components for each image pixel.
We describe the design and performance of a color real-time autostereoscopic 3D display based on our partial pixel 3D display architecture. The primary optical components are an active-matrix liquid crystal display and a diffractive optical element overlay. The display operates at video frame rats and is driven with a conventional VGA signal. 3D animations with horizontal motion parallax are readily viewable as sets of stereo images. The measured contrast and perceived brightness of the display are excellent, but there are minor flaws in image quality due to secondary images.
The ICVision system provides the functional equivalent of a real-time holographic stereogram. Using diffractive optics, the system creates a set of discrete viewing regions called virtual viewing slits. Each pixel of the display fills each viewing slit with different image data. When the images presented in two virtual viewing slits separated by an interoccular distance are filled with stereoscopic pair images, the observer sees a 3D image. The images are computed so that a different stereo pair is presented each time the viewer moves approximately 1 eye pupil diameter (approximately 3 mm), thus providing a series of stereo views. The current embodiment of the ICVision display is realized by integrating a diffractive optical element with a conventional AMLCD. The authors have previously reported on the design of static displays and real-time monochromatic full motion displays. This paper discusses the design details of a full color display. The current system does not require the use of color filters within the AMLCD. A portable version of the real-time color display will be demonstrated at the conference.
We describe the properties of diffractive gratings induced in nematicliquid crystal thin films by fringing electrostatic fields induced by interdigitated ITO electrodes. The index of refraction variation produced by fringing fields gives rise to strong diffraction with resolution constrained only by the available lithography.
KEYWORDS: Diffraction gratings, 3D displays, Holography, Modulators, Eye, Very large scale integration, LCDs, Diffraction, Stereo holograms, Computing systems
There is increasing interest in real-time autostereoscopic 3D displays. Such systems allow 3D objects or scenes to be viewed by one or more observers with correct motion parallax without the need for glasses or other viewing aids. Potential applications of such systems include mechanical design, training and simulation, medical imaging, virtual reality, and architectural design. One approach to the development of real-time autostereoscopic display systems has been to develop real-time holographic display systems. The approach taken by most of the systems is to compute and display a number of holographic lines at one time, and then use a scanning system to replicate the images throughout the display region. The approach taken in the ICVision system being developed at the University of Alabama in Huntsville is very different. In the ICVision display, a set of discrete viewing regions called virtual viewing slits are created by the display. Each pixel is required fill every viewing slit with different image data. When the images presented in two virtual viewing slits separated by an interoccular distance are filled with stereoscopic pair images, the observer sees a 3D image. The images are computed so that a different stereo pair is presented each time the viewer moves 1 eye pupil diameter (approximately mm), thus providing a series of stereo views. Each pixel is subdivided into smaller regions, called partial pixels. Each partial pixel is filled with a diffraction grating that is just that required to fill an individual virtual viewing slit. The sum of all the partial pixels in a pixel then fill all the virtual viewing slits. The final version of the ICVision system will form diffraction gratings in a liquid crystal layer on the surface of VLSI chips in real time. Processors embedded in the VLSI chips will compute the display in real- time. In the current version of the system, a commercial AMLCD is sandwiched with a diffraction grating array. This paper will discuss the design details of a protable 3D display based on the integration of a diffractive optical element with a commercial off-the-shelf AMLCD. The diffractive optic contains several hundred thousand partial-pixel gratings and the AMLCD modulates the light diffracted by the gratings.
The ICVision system is a diffractive display based on VLSI and liquid crystal technologies which displays the functional equivalent of a real-time holographic stereogram. We have previously reported several static ICVision displays, based on the partial pixel architecture, that displays a fixed 3D scene. Herein we report the first real-time implementation of an ICVision display (also based on the partial pixel architecture) that displays the functional equivalent of a real-time holographic stereogram. The device is constructed using a diffractive optical element and a separate liquid crystal display. The animated sequence is pre-computed then played back in real-time using standard VGA on a 80386 or higher PC. The display, drive electronics, and computer may be battery powered making the display suitable for portable use.
The ICVision system is a diffractive display based on VLSI and liquid crystal technology designed to compute and display holographic stereograms in real-time. The diffractive display is formed on the surface of standard integrated circuit chips which have been covered with a liquid crystal overlay. Fringing electrostatic fields generated by indium tin oxide electrodes on top of the integrated circuit are used to induce the actual diffractive display. A large display may be assembled from several hundred individual dies. Within each individual die making up the ICVision display will be the processor that computes the image to be displayed. This paper describes the design of image storage and drive electronics for the ICVision display. The proposed electronics allow the fabrication of an individual static ram cell and d/a converter for each of the tens of thousands of diffractive elements that make up a ICVision display.
We present an integrated analysis of the effects of optical crosstalk and electronic noise on the BER performance of angular and spatially multiplexed volume holographic data storage systems. Our results show that increasing the SLM contrast ratio beyond 30 is of limited benefit in improving the system BER, and that electronic noise in the CCD is the dominant noise source when the signal is not shot noise limited (for ideal holographic materials). In addition, we show that CCD's with 100 or more low noise output channels are needed to achieve a 1 Gbit/sec readout data rate for reasonable preamp data bandwidths of 20 MHz or less.
The ICVision system is a diffractive display based on VLSI technology. It is designed to display holographic stereograms in real-time. The diffractive display is formed on the surface of standard integrated circuit chips which have been covered with a liquid crystal overlay. Fringing electrostatic fields generated by indium tin oxide electrodes on top of the integrated circuit are used to induce the actual diffractive display. Within the individual IC die making up the display will be computational engines that compute the image to be displayed. Because grating information is encoded in the ITO gratings at the time of chip fabrication, the actual real-time computation is several orders of magnitude less than previous approaches. A large display may be formed by a tessellation of several hundred IC die, each approximately 1 cm2, on a flat substrate. An optical broadcast system would be used to transfer imagery information into the integrated circuits, obviating the need for wire bond attachments. This paper presents details of the overall architecture of the display system, and details of the holographic grating computations.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.