Showing papers on "Bend radius published in 2010"
TL;DR: This work demonstrates organic transistors and complementary circuits that continue to operate without degradation while being folded into a radius of 100 μm, enabled by a very thin plastic substrate, an atomically smooth planarization coating and a hybrid encapsulation stack that places the transistors in the neutral strain position.
Abstract: Flexible electronic circuits are an essential prerequisite for the development of rollable displays, conformable sensors, biodegradable electronics and other applications with unconventional form factors. The smallest radius into which a circuit can be bent is typically several millimetres, limited by strain-induced damage to the active circuit elements. Bending-induced damage can be avoided by placing the circuit elements on rigid islands connected by stretchable wires, but the presence of rigid areas within the substrate plane limits the bending radius. Here we demonstrate organic transistors and complementary circuits that continue to operate without degradation while being folded into a radius of 100 μm. This enormous flexibility and bending stability is enabled by a very thin plastic substrate (12.5 μm), an atomically smooth planarization coating and a hybrid encapsulation stack that places the transistors in the neutral strain position. We demonstrate a potential application as a catheter with a sheet of transistors and sensors wrapped around it that enables the spatially resolved measurement of physical or chemical properties inside long, narrow tubes.
1,144 citations
TL;DR: A statistical theory for crosstalk in multicore fibers is derived from coupled-mode equations including bend-induced perturbations, which allows efficient and accurate estimates of cross-talk for realistic telecommunications links.
Abstract: A statistical theory for crosstalk in multicore fibers is derived from coupled-mode equations including bend-induced perturbations. Bends are shown to play a crucial role in crosstalk, explaining large disagreement between experiments and previous calculations. The average crosstalk of a fiber segment is related to the statistics of the bend radius and orientation, including spinning along the fiber length. This framework allows efficient and accurate estimates of cross-talk for realistic telecommunications links.
152 citations
04 Nov 2010
TL;DR: In this paper, it was experimentally and theoretically confirmed for the first time that inter-core crosstalk can be varied more than 20dB depending on bending radius, and the results based on coupled-mode equation with equivalent index model were in good agreement with measurement results.
Abstract: It was experimentally and theoretically confirmed for the first time that inter-core crosstalk can be varied more than 20dB depending on bending radius Simulation results based on coupled-mode equation with equivalent index model are in good agreement with measurement results
115 citations
TL;DR: In this paper, a transparent conductive polymer-based strain-sensor array was developed for touch input sheets of flexible displays, which was able to sustain mechanical bending 300 times at a bending radius of 5 mm.
Abstract: A transparent conductive polymer-based strain-sensor array, designed especially for touch input sheets of flexible displays, was developed. A transparent conductive polymer, namely poly(3, 4-ethylenedioxythiophene):polystyrenesulfonate (PEDOT:PSS), was utilized owing to its strength under repeated mechanical bending. PEDOT:PSS strain sensors with a thickness of 130 nm exhibited light transmittance of 92%, which is the same as the transmittance of ITO electrodes widely used in flat panel displays. We demonstrated that the sensor array on a flexible sheet was able to sustain mechanical bending 300 times at a bending radius of 5 mm. The strain sensor shows a gauge factor of 5.2. The touch point on a flexible sheet could be detected from histograms of the outputs of the strain sensors when the sheet was pushed with an input force of 5 N. The touch input could be detected on the flexible sheet with a curved surface (radius of curvature of 20 mm). These results show that the developed transparent conductive polymer-based strain-sensor array is applicable to touch input sheets of mechanically bendable displays.
94 citations
TL;DR: In this paper, a light intensity modulation fiber-optic sensor was developed to measure curvature directly, which is suitable for the measurement of thin, embedded or highly flexible structures.
Abstract: A light intensity modulation fiber-optic sensor, which can measure curvature directly, has been developed. It is suitable for the measurement of thin, embedded or highly flexible structures. An experimental analysis on the static and dynamic characteristics of sensor has been undertaken. The results show that the output voltage has polarity and a good linear relationship with curvature when the curvature radius is larger than 60 mm. The mathematical model relating the relative output loss, parameters of sensitive zone’s configuration (depth, number, height and half angle of tooth) and bending radius is described analytically based on the geometric optics. Curvature fiber-optic sensors can be used to build a quasi-distributed fiber-optic sensor system, which can measure curvature and torsion angle simultaneously.
62 citations
TL;DR: In this article, the effects of bending radius (4-15 mm, with steps of 1 mm) and wrapping turns (up to 40 turns) on optical power loss were investigated.
Abstract: Loss of optical power in a single-mode optical fibre due to bending has been investigated for a wavelength of 1550 nm. In this experiment, the effects of bending radius (4–15 mm, with steps of 1 mm), and wrapping turns (up to 40 turns) on loss have been studied. Twisting the optical fibre and its influence on power loss also have been investigated.
61 citations
TL;DR: In this article, a-Si TFT fabrication technology using 80-μm ultrathin stainless steel foil as the substrate and integrating driver electronic in the display panel was introduced.
Abstract: This paper introduces the technology behind developing of flexible AM-OLED displays with improved color and reduced bending radius. Developing a-Si TFT fabrication technology using 80-μm ultrathin stainless steel foil as the substrate and integrating driver electronic in the display panel, we were able to demonstrate a full-color AM-OLED displayed in a curvature of less than 5 cm bending radius. Total panel thickness of 0.30 mm, brightness of 100 cd/m2 and color reproducibility of 63% were achieved.
61 citations
TL;DR: The design of a novel flexible very large mode area photonic crystal fibre for short pulse high peak power fibre laser and beam delivery applications and the major features of this fibre are explored, including the dependence of the mode field area on the fibre core shape, the influence of the bending radius and of thebending direction.
Abstract: We report on the design of a novel flexible very large mode area photonic crystal fibre for short pulse high peak power fibre laser and beam delivery applications. This fibre has an extremely large mode area exceeding 2500 µm2 when kept straight and over 1000 µm2 when bent over a 10 cm radius at a wavelength of 1064 nm. In addition our fibre exhibits very small fundamental mode bending loss below 10−2 dB/m. The large difference between the propagation loss levels of fundamental and higher order modes forces efficient single-mode guidance in the fibre core while bent. This allows using the fibre to build compact high power laser systems. The paper further explores the major features of this fibre including: the dependence of the mode field area on the fibre core shape, the influence of the bending radius and of the bending direction as well as the impact of manufacturing tolerances on the fibre specifications.
54 citations
TL;DR: Low-loss chalcogenide (As(2)S(3)) waveguides on a LiNbO(3) substrate for the mid-IR wavelength (4.8 μm) are demonstrated and the coupling efficiency is estimated to be 81%.
Abstract: We demonstrate low-loss chalcogenide (As2S3) waveguides on a LiNbO3 substrate for the mid-IR wavelength (4.8μm). Designed for single-mode propagation, they are fabricated through photolithography and dry-etching technology and characterized on a mid-IR measurement setup with a quantum cascade laser. For straight waveguides, propagation loss as low as 0.33dB/cm is measured and low-loss bends on the order of 100μm are simulated, with measurement results showing <3dB for a 250μm bend radius. The coupling efficiency is estimated to be 81%. In addition, the influences of variations in width and bend radius are also investigated.
37 citations
01 May 2010
TL;DR: In this paper, a flexible TFT backplane structure with improved mechanical reliability has been fabricated on a plastic substrate using amorphous indium-gallium-zincoxide (a-IGZO) thin film transistors.
Abstract: A new flexible TFT backplane structure with improved mechanical reliability has been fabricated on a plastic substrate using amorphous indium-gallium-zinc-oxide (a-IGZO) thin film transistors. The panel withstood 10,000 bending cycles at a bending radius of 5 mm without any noticeable TFT degradation. After the bending test, change of Vth, mobility, sub-threshold slope, and gate leakage current were only −0.10V, −0.11cm2/V-s, 0.01V/decade, and −1.03×10-−12A, respectively. No line defects, dark spots, or bright spots appeared after 10K bending cycles at a bend radius of 10 mm.
35 citations
TL;DR: In this paper, a three-dimensional finite-element model of the rotary-draw bending process of thin-walled rectangular tubes with small bending radius was developed based on ABAQUS/Explicit code and its reliability was validated by experiment.
TL;DR: Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers by means of selective water infiltration, rendering the exposed part of a nanoporous polymer block hydrophilic.
Abstract: Nanoporous Solid-Liquid core waveguides were prepared by UV induced surface modification of hydrophobic nanoporous polymers. With this method, the index contrast (δn = 0.20) is a result of selective water infiltration. The waveguide core is defined by UV light, rendering the exposed part of a nanoporous polymer block hydrophilic. A propagation loss of 0.62 dB/mm and a bend loss of 0.81 dB/90° for bend radius as low as 1.75 mm was obtained in these multimode waveguides.
Patent•
05 May 2010
TL;DR: In this article, a machine for continuously bending an elongated workpiece at predetermined radii is described, which uses a series of driving rollers (1, 2, 3 ) for bending.
Abstract: A machine for continuously bending an elongated workpiece at predetermined radii, machine that uses a series of driving rollers ( 1, 2, 3 ) for bending, includes a 2D laser displacement sensor ( 5 ) downstream the series of driving rollers ( 1, 2, 3 ) for bending and a computer ( 7 ) that is coupled among other to the 2D laser displacement sensor ( 5 ) for calculating a radius of a bend section and comparing the calculated radius of curvature with the desired radius of curvature. The computer ( 7 ) is coupled to a length meter ( 4 ) for measuring a length of the bend section concentrically to the elongated workpiece (T) and, further, to operating elements ( 8 ) adapted to operate a roller ( 2 ) of the series of driving rollers ( 1, 2, 3 ) for bending in order to adjust it on the base of a difference between the measured radius of curvature and the desired radius of curvature.
TL;DR: In this article, the effects of particle size, particle density, and bend radius ratio on pressure drop over the bend pipeline were also analyzed, and the calculated results of pressure gradient were found to be in good agreement with the measured data, with a fitting slope of 0.781 for the first horizontal straight pipeline and 1.017 for horizontal bend.
TL;DR: It is shown that the bound state below the first transverse threshold of the straight arm always exists if the inner extrapolation length is not larger than the outer one, and conditions of the bound-state existence for the different Robin parameters on the opposite edges are analyzed.
Abstract: A model of a thin straight strip with a uniformly curved section and with boundary requirements zeroing at the edges a linear superposition of the wave function and its normal derivative (Robin boundary condition) is analyzed theoretically within the framework of the linear Schrodinger equation and is applied to the study of the processes in the bent magnetic multilayers, superconducting films and metallic ferrite-filled waveguides. In particular, subband thresholds of the straight and curved parts of the film are calculated and analyzed as a function of the Robin parameter 1/Lambda , with Lambda being an extrapolation length entering Robin boundary condition. For the arbitrary Robin coefficients which are equal on the opposite interfaces of the strip and for all bend parameters the lowest-mode energy of the continuously curved duct is always smaller than its straight counterpart. Accordingly, the bound state below the fundamental propagation threshold of the straight arms always exists as a result of the bend. In terms of the superconductivity language it means an increased critical temperature of the curved film compared to its straight counterpart. Localized-level dependence on the parameters of the curve is investigated with its energy decreasing with increasing bend angle and decreasing bend radius. Conditions of the bound-state existence for the different Robin parameters on the opposite edges are analyzed too; in particular, it is shown that the bound state below the first transverse threshold of the straight arm always exists if the inner extrapolation length is not larger than the outer one. In the opposite case there is a range of the bend parameters where the curved film cannot trap the wave and form the localized mode; for example, for the fixed bend radius the bound state emerges from the continuum at some nonzero bend angle that depends on the difference of the two lengths Lambda at the opposite interfaces. Various transport properties of the film such as interference blockade of the current flow at some special energies is also discussed with the special attention being paid to the transformation from the Dirichlet to the Neumann case as the extrapolation length Lambda sweeps the positive axis.
Patent•
19 May 2010
TL;DR: In this paper, a flexible syphon core mold is proposed, which comprises a core head body (6), a connecting shaft (5), ball joints (3), a positioning key (11), core head sleeve (2), and an elastic clamp ring (1) which are in mechanical connection.
Abstract: The invention relates to a flexible syphon core mould, which comprises a core head body (6), a connecting shaft (5), ball joints (3), a positioning key (11), a core head sleeve (2) and an elastic clamp ring (1) which are in mechanical connection. The ball joints (3) are arranged in the core head sleeve (2) as core heads; a plurality of ball joints (3) are linked through the nested cooperation between balls and ball sockets and are axially positioned by the clamp ring (1) and the positioning key (11); and the outside diameter of each point on the surface of an outer circle of the core head sleeve (2) is equal to the diameter of the core head body (6) in order that each point of the outer surface of the core head sleeve (2) can be matched with the inner wall of a tube (4). In use, the core head sleeve (2) can freely rotate around the ball joints by the movable ball joint so as to meet the requirement for the bending and forming curvature of tubing. The flexible siphon core mould can smoothly bend a large-calibre thin-wall tube with the smallest relative bending radius of 1.0 decimeter, can control the ellipticity of the formed tubing within 5 percent and has the characteristics of compact structure, easy replacement of main wearing parts and strong universality.
TL;DR: Wang et al. as mentioned in this paper developed a wrinkling prediction model based on the deformation theory of plasticity combined with the energy method, and then the minimum bending radius without the occurrence of wrinkling in the process was obtained.
Patent•
25 Feb 2010
TL;DR: In this paper, a tubular cable bend limiter is fixed at one end to the collar and the limiter directs a cable containing one or more bend insensitive fibers through a bend of, e.g., 90 degrees, between the collar between the cable and the opposite end of a limiter with a fiber bend radius of less than one inch (25.4 mm).
Abstract: A connector that enables fiber optic cables to terminate at equipment in cabinets having little space available for cable routing, without over bending. The construction includes a connector housing, and a yoke including a collar joined to a rear end of the housing. A tubular cable bend limiter is fixed at one end to the collar and the limiter directs a cable containing one or more bend insensitive fibers through a bend of, e.g., 90 degrees, between the collar and the opposite end of the limiter with a fiber bend radius of less than one inch (25.4 mm). If the limiter creates a fiber bend radius of 0.300 inch (7.62 mm), the distance between the front of the connector and the cable after bending may be as little as 1.26 inches (32 mm), allowing the cable and connector to be routed and terminated in limited space without impairing performance.
04 Nov 2010
TL;DR: In this paper, the authors characterize an approach to make compact low loss silica on silicon waveguides and achieve good agreement with theory, achieving record low losses of 8 dB/m for 0.5mm bend radius.
Abstract: We characterize an approach to make compact low loss silica on silicon waveguides and achieve good agreement with theory. Record low losses of 8 dB/m for 0.5-mm bend radius down to 3 dB/m for 2-mm bend radius were achieved.
Patent•
08 Jul 2010TL;DR: In this article, the optical fiber remains within a radius (r) of the axis (21) which may be less than the minimum bend radius of a single optical fiber, and a mechanical coupling between the components remains parallel to the axis.
Abstract: A device including first and second components respectively including first and second circuits interconnected by a flexible panel including an optical fiber (20) wherein the optical fiber (20) has a longitudinal segment which traverses a curved path including a radial component about an axis (21) and crosses a mechanical coupling between the components, wherein the longitudinal segment has a component in a direction parallel to the axis (21). The longitudinal segment remains within a radius (r) of the axis (21) which may be less than the minimum bend radius of the optical fiber (20).
TL;DR: In this article, the authors studied the effect of air shock wave propagation in underground mines by means of a numerical simulation approach and showed that the air shockwave attenuation of the peak overpressure with distance does not obey exponent law.
Patent•
27 Aug 2010
TL;DR: A fiber organizer tray comprises a generally rectangular or oblong body having a first side and an opposite second side as discussed by the authors, which is configured to route and provide slack storage for a plurality of jacketed cables.
Abstract: A fiber organizer tray comprises a generally rectangular or oblong body having a first side and an opposite second side. The first side is configured to route and provide slack storage for a plurality of jacketed cables. The first side includes a winding cable guide that routes multiple jacketed cables a predetermined distance in a manner in which the multiple jacketed cables do not cross over themselves and do not experience a cable bend that violates a minimum bend radius of an optical fiber portion of the jacketed cable. The second side of the organizer tray is configured to route and splice a plurality of the drop cables to a plurality of optical fiber pigtails. The fiber organizer tray can be implemented in a telecommunication enclosure having a distribution management unit and a jacketed cable management unit disposed therein. The telecommunication enclosure can be configured as a fiber distribution terminal (FDT) for managing telecommunication lines, especially optical fiber telecommunication lines, in a building, such as an MDU or other location.
21 Mar 2010
TL;DR: In this article, the authors demonstrate for the first time that large diameter step index POF can be used for 10 Gbit/s transmission over up to 25 m with very low-cost components and DMT modulation.
Abstract: In this paper we demonstrate for the first time that large diameter (½ to 1 mm) step index POF can be used for 10 Gbit/s transmission over up to 25 m with very low-cost components and DMT modulation. The use of bend insensitive multi-core POF reduces the bending radius to 2.5 mm without any signal distortion resulting in a very robust installation.
Patent•
24 Feb 2010
TL;DR: In this paper, a sheet metal component is made of steel armor and is formed as a profile component with a bend, where the profile component is manufactured from an armored steel plate by hot forming in a single-piece manner.
Abstract: The sheet metal component (1) is made of steel armor and is formed as a profile component with a bend (3), where the profile component is manufactured from an armored steel plate by hot forming in a single-piece manner. A bending radius (R) corresponds a wall thickness (D) of the armored steel plate. The bend runs over the entire length of the profile bar.
TL;DR: In this paper, a transition region with a step taper between the straight and bent portions of the waveguide was proposed to reduce the mode transition loss between the two parts of a waveguide.
Abstract: Strong confinement of light in silicon waveguides allows for sharp bends and, as a result, high-density integration. However, the mode transition loss between the straight and bent portions of a silicon waveguide begins to affect the device performance when the bending radius becomes small. In this letter, we show that a transition region with a step taper between the straight and bent portions of the waveguide can effectively reduce this transition loss. This is demonstrated by measuring the intrinsic round-trip losses of micro-racetrack resonators, where ultralow loss can be precisely characterized according to the quality (Q)-factor change. The results show that the taper can suppress the transition loss from 0.016 to 0.0022 dB for a 4.5-μ m bend radius. Consequently, we improve the Q-factor of such a racetrack resonator from 31 000 to 87 000.
TL;DR: In this paper, an epoxy packaged surface mountable fiber temperature sensor for engineering applications is presented, which consists of a single turn of a bare bend sensitive single-mode fiber with an applied absorption coating.
Abstract: An epoxy packaged surface mountable fibre temperature sensor for engineering applications is presented in this paper. The temperature sensor is based on a macro-bend single-mode fibre loop employed in a ratiometric power measurement scheme and has a linear characteristic with temperature at a fixed wavelength and bend radius. The sensor head consists of a single turn of a bare bend sensitive single-mode fibre with an applied absorption coating. The temperature of the sensor head is varied up to 80 °C and the linearity of the response is studied with different applied absorption coatings. The sensor head is packaged in a low thermal expansion coefficient two-part epoxy for stability. Such a packaged sensor head can be directly attached to any structure for temperature measurements. The packaged sensor system shows a temperature resolution better than 0.5 °C. The impact of stress and strain on the fabricated sensor is investigated by applying an external load to the sensor and an estimation of magnitude of the stress- and strain-induced error in the temperature measurement of the system has been obtained. It is found that the impact of stress and strain is low and can be compensated, if necessary. A portable prototype of the sensor head and the interrogation system is also demonstrated in this paper. The demonstrated temperature sensing system could be used for a wide range of engineering applications.
TL;DR: In this article, critical bending radii of some organic thin films were predicted using nanoindentation data and a prediction equation, assuming that dimensional changes in the films give rise to electrical changes.
TL;DR: The bending loss characteristics of the hybrid plasmonic waveguide are investigated theoretically and experimentally and results showed that the guided mode is confined mainly into outer high index slab as the bending radius decreases.
Abstract: The bending loss characteristics of the hybrid plasmonic waveguide are investigated theoretically and experimentally. Simulation results showed that the guided mode is confined mainly into outer high index slab as the bending radius decreases. Thus, the radiation loss due to bending is greatly suppressed. We fabricate flexible hybrid plasmonic waveguide consisted of 5 nm-thick Au stripe and flexible multiple polymer cladding layers. The measured bending loss is lower than 1 dB/180° at a wavelength of 1310 nm for the bending radii down to 2 mm.
TL;DR: In this article, a 10.7-Gb/s transmission over 25m multicore polymer optical fiber (MC-POF) is reported, which allows a robust transmission and ease of installation including tight bends.
Abstract: We report on 10.7-Gb/s transmission over 25-m multicore polymer optical fiber (MC-POF) which allows a robust transmission and ease of installation including tight bends. The discrete multitone modulation technique is applied to the intensity-modulated direct-detection optical channel in order to achieve high spectral efficiency. The use of bend-insensitive MC-POF reduces significantly the admissible bending radius to 2.5 mm without any signal distortion resulting in a very robust installation. The POF-optimized receiver comprises a silicon pin photodiode with an active diameter of 400 and a transimpedance amplifier.
Patent•
15 Dec 2010
TL;DR: In this article, a flexible, small diameter fiber optic is sheathed in a small diameter flexible tube comprising the distal tip of the probe, which allows the fiber to be bent in a tight radius, with low tube bending forces during insertion, providing a compact design which eliminates the need for a straight distal portion of flexible tube extending from the cannula.
Abstract: A probe having a flexible, small diameter fiber optic sheathed in a small diameter flexible tube comprising the distal tip of the probe. The small diameters of the fiber and tube allow the fiber to be bent in a tight radius comprising the major portion of the length of the exposed portion of the fiber, with low tube bending forces during insertion, providing a compact design which reduces or eliminates the need for a straight distal portion of flexible tube extending from the cannula. The small diameter tube also allows a greater wall thickness outer cannula to be used, thereby increasing instrument rigidity. One embodiment encompasses a larger flexible tube with corresponding larger bend radius, to encase a plurality of fiber optics, providing separately optimized laser and illumination delivery paths. Anti-friction coating material may be used to further reduce insertion forces.