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Bimorph

About: Bimorph is a research topic. Over the lifetime, 3339 publications have been published within this topic receiving 51880 citations.


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Patent
31 Aug 1992
TL;DR: In this article, a beam deflector for a bar code reader optical system having a variable focus zoom lens system is described, where one or more cantilever mounted piezoelectric bimorph elements support a scanning mirror, or a focusing lens, or laser diode, or an aperture and limiting aperture, for movement at the free ends of the bimomorph elements to produce a scanning of the bar code readers optical system.
Abstract: Several embodiments are disclosed of bar code readers in which one or more piezoelectric bimorph elements are utilized as a drive element in the optical system thereof In different embodiments, the piezoelectric bimorph element is utilized in the scanning function of the bar code reader optical system, or in a variable focus zooming function of the optical system The bar code readers are provided with improved decoding reliability, speed and orientation freedom, with regular or high density, one or two dimensional bar codes, by using multiple beam symbol crossings, created by using one or more piezoelectric bimorph elements In different disclosed embodiments, one or more cantilever mounted piezoelectric bimorph elements support a scanning mirror, or a focusing lens, or a laser diode, or a laser diode and limiting aperture, for movement at the free ends of the bimorph elements to produce a scanning of the bar code reader optical system Several disclosed embodiments of the subject invention provide a beam deflector for a bar code reader optical system having a variable focus zoom lens system in which one or more cantilever mounted piezoelectric bimorph elements control the variable focus zoom lens system 1

64 citations

Journal ArticleDOI
Ho-Jun Lee1
TL;DR: In this paper, a layerwise finite element formulation for piezoelectric materials is used to investigate the displacement and stress response of a functionally graded bimorph actuator, where the layerwise laminate theory is implemented into a linear beam element in order to provide a more accurate representation of the transverse and shear effects that are induced by the increased inhomogeneities introduced through-the-thickness by the functionally graded materials.
Abstract: A layerwise finite element formulation developed for piezoelectric materials is used to investigate the displacement and stress response of a functionally graded piezoelectric bimorph actuator. The formulation is based on the principles of linear thermopiezoelectricity and accounts for the coupled mechanical, electrical, and thermal responses of piezoelectric materials. The layerwise laminate theory is implemented into a linear beam element in order to provide a more accurate representation of the transverse and shear effects that are induced by the increased inhomogeneities introduced through-the-thickness by the functionally graded materials. The accuracy of the formulation is verified with previously published experimental results for a piezoelectric bimorph actuator. Additional studies are conducted to analyze the impact of electric and thermal loads on the deflections and stresses in a bimorph actuator. Results of the study help to demonstrate the capability of the layerwise theory to provide a more ...

63 citations

Journal ArticleDOI
TL;DR: In this article, a 2D auxetic substrate is sandwiched between two piezoelectric layers, which is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezelectric layer when subjected to a longitudinal stretching load.
Abstract: This letter presents a piezoelectric bimorph with auxetic (negative Poisson’s ratio) behaviors for increased power output in vibration energy harvesting. The piezoelectric bimorph comprises a 2D auxetic substrate sandwiched between two piezoelectric layers. The auxetic substrate is capable of introducing auxetic behaviors and thus increasing the transverse stress in the piezoelectric layers when the bimorph is subjected to a longitudinal stretching load. As a result, both 31- and 32-modes are simultaneously exploited to generate electric power, leading to an increased power output. The increasing power output principle was theoretically analyzed and verified by finite element (FE) modelling. The FE modelling results showed that the auxetic substrate can increase the transverse stress of a bimorph by 16.7 times. The average power generated by the auxetic bimorph is 2.76 times of that generated by a conventional bimorph.

63 citations

Journal ArticleDOI
TL;DR: Kim et al. as discussed by the authors presented a photothermally foldable soft bimorph by dry transfer of poly(3,4-ethylenedioxythiophene)s (PEDOT) onto poly(dimethylsiloxane) film.
Abstract: A photothermally foldable soft bimorph was prepared via the dry transfer of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with tosylate onto a poly(dimethylsiloxane) film. The photothermal folding was optimized via reversible actuation by controlling the thickness of each layer and the temperature increase to afford large deflection and displacement up to 150° and >20 mm, respectively, upon exposure to near-infrared (NIR) light (808 nm). A two-dimensional array of the bimorph converted into complex three-dimensional architectures, such as a Venus flytrap, under light and reversibly unfolded in the dark. Taking advantage of the photothermal nature of PEDOT, a localized heat pocket was generated inside the folding structure. Thus, a Venus flytrap with a hot pocket reaching 100 °C was realized for the first time. The Venus flytrap could trap and move an object within a few seconds of NIR exposure. A bilayer material that behaves like a Venus flytrap when illuminated by infrared light has been created by researchers in South Korea. Biomimetic materials – substances that replicate the behavior of biological organisms and structures – offer a route to producing engineered devices with novel functionality. The biomimetic material made by Eunkyoung Kim and colleagues from Yonsei University consists of two soft polymers – a spin–coated layer of polydimethylsiloxane (PDMS) on a spin-coated film of poly (3, 4–ethylenedioxythiophene) (PEDOT) doped with tosylate. PEDOT has photothermal properties, meaning that incident light leads to localized heating. This heat then changes the volume of the PDMS, which makes the bilayer fold. The team used this effect to create complex three–dimensional architectures and hot trap including a Venus flytrap, which snapped close within a few seconds of being exposed to near–infrared radiation. A photothermally foldable soft bimorph was prepared by dry transfer of poly(3,4-ethylenedioxythiophene)s (PEDOT) onto poly(dimethylsiloxane) film. The reversible folding nature of the soft bimorph was programmable to convert the two-dimensional (2D) array of bimorph into complex three-dimensional (3D) architectures such as Venus flytrap under light. These 3D structures were returned reversibly to the original unfolded 2D structures under dark. The Venus flytrap could perform a task to snap and move an object within few second of near-infrared exposure. A localized heat pocket was generated inside the folding structure due to the large photothermal effect of PEDOT.

63 citations

Proceedings ArticleDOI
16 Jun 1997-Sensors
TL;DR: In this paper, an adjustable inductor which is digitally controlled by microrelays has been made using combined surface and bulk micromachining technology using a TaSi/sub 2/SiO/Sub 2/ bimorph cantilever beam, a gold-to-gold electrical contact, aluminum as sacrificial layer, and a combined electrostatic and thermal actuation mechanism.
Abstract: An adjustable inductor which is digitally controlled by microrelays has been made using combined surface and bulk micromachining technology. The microrelays were fabricated using a TaSi/sub 2//SiO/sub 2/ bimorph cantilever beam, a gold-to-gold electrical contact, aluminum as sacrificial layer, and a combined electrostatic and thermal actuation mechanism. The silicon substrate underneath the inductor region was etched out to reduce the substrate eddy current loss. Sixteen different inductance values ranging from 2.5 nH to 324.8 nH were obtained using four microrelays. The minimum self-resonant frequency is 1.9 GHz. The lowest measured thermal power and electrostatic voltage for the combined actuation of microrelays are 8.0 mW and 20 V, respectively. The measured contact resistance is typically 0.6 to 0.8 ohms.

63 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202358
2022116
202191
202090
2019123
2018117