Bimorph

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

Energy harvesting MEMS device based on thin film piezoelectric cantilevers

Abstract: A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), energy harvesting MEMS device is developed to enable self-supportive sensors for in-service integrity monitoring of large social and environmental infrastructures at remote locations. It is designed to resonate at specific frequencies of an external vibrational energy source, thereby creating electrical energy via the piezoelectric effect. Our cantilever device has a PZT/SiNx bimorph structure with a proof mass added to the end. The Pt/Ti top electrode is patterned into an interdigitated shape on top of the sol-gel-spin coated PZT thin film in order to employ the d 33 mode. The base-shaking experiment at the first resonant frequency of the cantilever (170 × 260 μm) generates 1 μW of continuous electrical power to a 5.2 MΩ resistive load at 2.4 V DC. The effect of proof mass, beam shape and damping on the power generating performance are modeled to provide a design guideline for maximum power harvesting from environmentally available low frequency vibrations. A spiral cantilever is designed to achieve compactness, low resonant frequency and minimum damping coefficient, simultaneously.

Modeling of a three-layer piezoelectric bimorph beam with hysteresis

Abstract: Piezoelectric actuators are usually stacked or bimorph in configuration. In this paper the mechanics of a three-layer piezoelectric bimorph is discussed and its dynamic model with hysteresis is presented. The results can be used to analyze piezoelectric actuators constructed with three-layer piezoelectric bimorphs. A piezoelectric bimorph actuator has been fabricated and experiments have been carried out to verify the model. The calculated results of this model closely matched the tested results. This model can also be used with other types of piezoelectric actuators with a slight modification.

Portable laser scanning arrangement for and method of evaluating and validating bar code symbols

Abstract: Laser light reflected from a bar code symbol pattern is detected by a photodetector mounted in a portable scanning head of a laser scanning system. By selecting appropriate threshold values on the analog signal generated by the photodetector, the analog signal is converted to a series of pulses, each pulse width accurately corresponding to the width of a bar from the scanned pattern. A plurality of functions can be determined from the series of pulses, each function being independently selected by keyboard entry from the head, displayed on the head, and/or recorded by a printer remote from the head. Single line or multiple line scans in two orthogonal directions relative to the pattern may be selected. A bimorph or speaker-type oscillatory element may be utilized as a miniature scanning element. Circuitry for synchronizing scanning along both axes, and for generating a signal to drive the bimorph in a uniform, constant velocity manner is also disclosed.

Piezoelectric Ceramics with Functional Gradients: A New Application in Material Design

Abstract: Internal strain amplification can be utilized in piezoelectric ceramics to obtain relatively large displacements. The monomorph described in the present work is a bending bar made from a single piece of material into which a smooth gradient of piezoelectric activity is introduced. The application of a voltage then causes the bar to bend due to the differential stresses that are induced. These are relatively uniformly distributed and do not peak in the center as in a conventional bimorph. Significantly increased life and reliability can then be achieved.

Ink-jet recording apparatus

Abstract: An ink-jet recording apparatus includes a film having a number of holes for holding ink. The film is driven in a predetermined direction near a recording paper. Ink is supplied to the holes by an ink supply mechanism. Ink in desired holes are heated by a thermal head to be ejected onto the recording paper. The thermal head is supported by a bimorph cell. In accordance with a voltage supplied from a voltage generator, the bimorph cell exponds or contracts to move the thermal head between a first position wherein the thermal head is adjacent to the recording paper and in contact with the film and a second position wherein the thermal head is separated from the recording paper and film.