Topic
Bend radius
About: Bend radius is a research topic. Over the lifetime, 3303 publications have been published within this topic receiving 35415 citations. The topic is also known as: minimum bend radius.
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Patent•
29 Mar 1996
TL;DR: In this paper, a flexible screened multi-wire flat cable portion is presented, which can be passed through a very narrow gap between the teeth of the upper and lower jaws for producing "bitewing" images, as well as periapical images with or without the use of a bite-block, by means of the intraoral X-ray CCD sensor.
Abstract: not available for EP0825832Abstract of corresponding document: WO9632064The present invention demonstrates thin flexible protected screened flat cable portion (3) for connection of an intraoral X-ray sensor (2) to its external electronic controller. According to the present invention, a flexible screened multi-wire flat cable portion (3) is produced, which can be passed through a very narrow gap between the teeth of the upper and lower jaws for producing "bitewing" images, as well as periapical images with or without the use of a bite-block, by means of the intraoral X-ray CCD sensor. The flexible screened flat multi-wire cable (3) permits sharp bending in different angles relative to the sensor capsule (1) with a very short bending radius and having an expected lifetime of several tens of thousands bendings with a small bending radius.
13 citations
TL;DR: In this paper, a silicon photonic filter with an ultra-large free spectral range (FSR) was proposed and demonstrated by introducing high-order adiabatic elliptical-microrings (AEMs) with bent directional couplers (DCs).
Abstract: A silicon photonic filter with an ultra-large free spectral range (FSR) is proposed and demonstrated by introducing high-order adiabatic elliptical-microrings (AEMs) with bent directional couplers (DCs). For the AEMs, the waveguides in the non-coupling regions are wide and have a minimal bending radius, while the waveguides in the coupling regions are relatively narrow and have a maximal bending radius. Both the radius and width of AEMs have varied adiabatically. Furthermore, bent DCs are used to realize a sufficient coupling between the access waveguide and the microring waveguide and suppress the higher-order mode excitation. The fabricated filters based on the 2nd-order, 3rd-order, and 4th-order AEMs have box-like spectral responses with an ultra-large FSR of ∼37 nm, which is a record for high-order microring filters to the best of our knowledge. Finally, an eight-channel silicon photonic filter with a channel-spacing of ∼3.2 nm and high extinction ratios of >30 dB is demonstrated.
13 citations
TL;DR: In this paper, a bending-insensitive single-mode photonic crystal fiber (PCF) was proposed based on the existence of a triangular core formed by three neighboring air holes missing in the center of the fiber and two cladding layers of air holes with different diameters.
13 citations
01 May 2018
TL;DR: In this article, a new test protocol has been developed for replicating the stresses of daily motion for flexible substrates and the effect of cyclic mechanical bending, exposure to human body temperature has been studied and analyzed using Flex-PCBs.
Abstract: Flexible electronics in wearable applications may be subjected to flexing, bending, stretching in addition to exposure to temperature and humidity. Presently, there is a general lack of test protocols for the reliability assessment and survivability assurance of the flexible substrates. Flexing and bending in operation may be accrued under stresses of daily motion. Flexible substrates often use serpentine patterns to accommodate high stretch in the neighborhood of 25-100 percent. Flexible copper traces subjected to cyclic mechanical bending result in stretching of the outside layers and simultaneously compressing the inner layers. Cyclic bending may also result in formation of wrinkles on the flexible substrate causing delamination. Meaningful accelerated test protocols and acceleration transforms relating test-performance to operational reliability are needed. In this paper, a new test protocol has been developed for replicating the stresses of daily motion for flexible substrates. The conventional-fabricated flexible circuits have been studied. Test coupons have been designed to include the common trace geometries encountered in flexible electronics applications. The effect of cyclic mechanical bending, exposure to human body temperature has been studied and analyzed using Flex-PCBs. Flex-PCBs have been subjected to cyclic bending and the failure modes were analyzed as a function of bend radius, bend angle and number of cycles to failure. Extremely tight bend radius and bend angle larger than 90° have been studied. Further, in order to monitor the resistance of copper traces and develop life prediction model, Data Acquisition unit has been used. This prognostic health monitoring technique captures the increase in resistance of copper traces with the growth in fatigue due to cyclic mechanical bending. The study addresses the need for life prediction models of flexible copper traces on flexible polyimide substrate.
13 citations
TL;DR: In this article, the authors outline a process for simulation of the calculated cable laying tension and bend radius with a set of physical tests developed for mechanical and water ingress protection, and outline a recent cable field joint onshore testing regime to ensure the cable joint integrity during the laying process as well as serviceability in operational life.
13 citations