PZT THIN FILMS FOR PIEZOELECTRIC MICROACTUATOR APPLICATIONS

Additionally, it generated an electrical signal of 60 mV pp as a sensor, while vibration was input by a shaker. Introduction between two platinum electrodes on a silicon cantilever as the active material. The driving signal was divided by 20 before sending to the oscilloscope in order to prevent the damage resulting from the high voltage. Tung YC, Kurabayashi K. It is assumed that the three silicon links between the unimorphs can be only twisted because of their high flexural rigidity i. The sensing tests were carried out by the function generator, the power amplifier, a shaker PCB Piezotronics, Inc. Hence, this can be viewed as a bounded-input optimization problem written as follows.

Strain measurements of silicon dioxide microspecimens by digital imaging processing. Experimental and theoretical results of the vibration of the cantilever specimen. A low applied voltages. Hysteresis behavior of PZT was modeled by allowing the effective electro-active piezoelectric strain coefficient, d 31,eff , to vary as a function of voltage, and the estimated d 31,eff values are plotted in figure By placing equation E. While engineering advances have enabled many break-throughs in the field of biomedical imaging, novel methods of endoscopic detection and diagnosis are still in great need.

This step was taken instead of a sustained poling process after observing the breakdown of PZT in other samples at the 15—20 V range. In a second experiment, an actuator with all four legs connected in parallel was driven to 15 V. T i and T n i matrices are used to map the position of the center of the stage to that of the end micfoactuator each leg, and T 2 and T 3 to map the piezoelecrtic residual moments to initial stage bending.

A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement

Received Feb 16; Accepted Apr 4. By including their effects the model captured microactuaotr experimental motion of the actuator more accurately. In order to achieve the required performance of the actuator in the limited footprint available, design trade-offs were identified, initially through a static model of the stage described in this section.

This result is the compilation of four individual beams from equation 2. Homogeneous nucleation was thus prevented, and the sizes of the PZT grains increased.

A minimum bandwidth of 10 Hz in the out-of-plane direction is also required to avoid motion artifacts caused by heartbeats, organ peristalsis, and respiratory displacement [ 1 ]. Electrothermal actuators can produce large displacements at a low voltage, e. The first three plots, a — cin figure 8 show the influence of the ratio of the length of the downward bending segment to that of the upward bending segment on the displacement and natural frequency in each actuation mode when the total length of the applicatiins is fixed.

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The sol was passed through a 0. Obtained using beam theory, equation 2. By equating tgin 5. Schematic drawing of cross-section of unimorph to show allowed thickness variation, where Gap refers to the thickness of the silicon layer that was etched away.

This comparison shows that piezoelsctric experimental results are similar to the theoretical results with an error of 5. In estimating the dynamic behavior of the legs, the perturbed model can represent the presence of other excited vibration modes better than the nominal model, although its averaged period is less accurate in comparison with the experimental result. If using this kind of ideal model, it is not possible to predict non-identical displacements of the four legs such as shown in figure 10which is caused most likely by structural asymmetry among the four legs and non-homogenous material properties due to non-uniform residual stresses.

The thickness of a film formed by conventional sol-gel processing typically does not reach 1 micron, while the charge accumulation associated with the material electric dipole is proportional to the film thickness. The response is sinusoidal and its frequency is identical to the driving frequency, indicating that the system is in the linear range, and that the PZT film can serve as an effective sensor for small structures.

Its central rectangular-shaped mirror platform, also referred to as the stage, is actuated by four symmetric PZT bending legs such that each leg provides vertical translation for microactuatoe corner of the stage. Sintering temperatures of over o C are required to yield adequate PZT particles. Additionally, the X-ray diffraction pattern reveals that the fabricated PZT film is perovskite phase with no pyrochlore phase.

Measurement of dynamic properties of MEMS and the possibilities of parameter identification by simulation. The oiezoelectric was optimised to achieve no sharp edges in the PZT layer. Then the photonic sensor measured the deflection w 1w 2 and w 3 of the cantilever at position 1, 2 and 3.

Different designs of these structures were made with cantilever widths between 60 and mm and lengths between and mm. Each layer was pyrolysed using hot fax: Now following the same steps as in Section 2—that is, calculating the reaction force, moment, and torsion for each leg and plugging them into the equation of motion for the stage—the expression for the dynamic motion of the center of the stage can be obtained, assuming it can be described as a standard lzt mass—spring—damper system:.

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The equation of motion for the stage, equation 2.

With this knowledge the microactuators were charac- The measurements were carried out without a previous terised using laser interferometry. Optical microscope image of a leg with labels to show allowed dimensional variation. In this paper, in addition to the design and performance of the proposed actuator, a modeling technique that incorporates the effects of residual stress and dimensional variation of the structures from static motion measurements is introduced.

Annu Rev Mater Res. The same mask was used for structuring the poly-silicon layer in a TMAH-based wet etching process. In scanning force micro- a LPCVD-Si3N4 layer was deposited and structured using a scopy piezoelectric cantilever structures are well established. As expected, increase in the total length with a fixed ratio of segment lengths results in increase in the displacement and decrease in the natural frequency.

Figure 1 schematically summarizes the overall preparation procedure.

A three-degree-of-freedom thin-film PZT-actuated microactuator with large out-of-plane displacement

Desu, Characterization and W. Table 1 Static displacements of the stage at 14V. In the perturbed model, the expression for the leg displacements, equation 2.

Lead Zirconate Titanate oxide PZT thick films with thicknesses of up to 10 mm were developed using a modified sol-gel technique. Measured cantilever resonance frequencies cantilever lengths: Engineering Materials, in Appendix C Equations 2.

Resonance frequency piezoelectfic on a mm long cantilever resulted in a value of 23 kHz. One novel optical imaging technique that can be used to achieve optical sectioning in high resolution for this task is dual axes confocal microscopy [ 1 — 5 ].

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