Piezoelectric Tuning Fork Research Articles

Piezoelectric tip-sample distance control for near field optical microscopes

An aluminum coated tapered optical fiber is rigidly attached to one of the prongs of a high Q piezoelectric tuning fork. The fork is mechanically dithered at its resonance frequency (33 kHz) so that the tip amplitude does not exceed 0.4 nm. A corresponding piezoelectric signal is measured on electrodes appropriately placed on the prongs. As the tip approaches within 20 nm above the sample surface a 0.1 nN drag force acting on the tip causes the signal to reduce. This signal is used to position the optical fiber tip to about 0 to 25 nm above the sample. Shear forces resulting from the tip-sample interaction can be quantitatively deduced.

Method of manufacturing a piezoelectric tuning fork resonator

A piezoelectric tuning fork resonator having a piezoelectric substrate provided with a stepped portion on its end and a tuning fork arm portion formed in the stepped portion. A dummy substrate is arranged adjacent to a side of the piezoelectric substrate and a pair of sealing substrates are pasted onto upper and lower portions of the piezoelectric substrate and the dummy substrate to form a chip type piezoelectric tuning fork resonator. In another embodiment, the piezoelectric substrate includes a resin sealing portion having a hollow portion defined around the tuning fork arm portion so as to form a resin-coated piezoelectric tuning fork resonator.

Piezoelectric tuning fork resonator and method for manufacturing the same

A piezoelectric tuning fork resonator having a piezoelectric substrate provided with a stepped portion on its end and a tuning fork arm portion formed in the stepped portion. A dummy substrate is arranged adjacent to a side of the piezoelectric substrate and a pair of sealing substrates are pasted onto upper and lower portions of the piezoelectric substrate and the dummy substrate to form a chip type piezoelectric tuning fork resonator. In another embodiment piezoelectric substrate includes a resin sealing portion having a hollow portion defined around the tuning fork arm portion so as to form a resin-coated piezoelectric tuning fork resonator.

Reflections on the Study of Piezoelectric Ceramics: Focusing on the Development of Electro-Mechanical Filters

This paper describes memories the author had when he made basic and application research into the piezoelectricity of barium titanate ceramics in a laboratory at Kyoto University during the first period (1947–1969) of Piezoelectric Ceramic Age. The paper covers the basic studies on electrostrictive phenomena and elastic vibration modes and the application studies on underwater ultrasonic transducers, piezoelectric type tuning forks and vibration reeds, both of which led to the development of piezoelectric type mechanical filters.

Microresonator of tuning fork configuration operating at its second overtone frequency

An improved piezoelectric tuning fork (12) is disclosed in which the electrodes which drive the tuning fork (30, 32, 34; 36, 38, 40; 42, 48, 50; 52, 54, 56; 58, 60, 62; 64, 66, 68) are positioned along the tines (16, 18) so as to optimize operation at the second overtone frequency.

Tuning fork Resonator Using Shear Mode Piezoelectric Ceramic

The purpose of the present investigation is to develop a piezoelectric tuning fork resonator with such small capacitance ratio that it can be used as an element of a filter with relatively wide band-width. The tuning fork resonator proposed in this paper is composed of a shear mode piezoelectric ceramic. From information obtained in this investigation, it is found that the 2nd mode of the tuning fork is effective in obtaining a small capacitance ratio; however, further research is necessary to develop a means of suppressing unwanted responses.

Piezoelectric ceramic tuning fork filters

Within the past year, marked progress has been made in the development of a class of low frequency ceramic tone filters offering significant advantages over existing filters in the 50 to 9000 cps range. These filters utilize a pair of piezoelectric ceramic Bimorph elements mounted and connected so that stress cancellation occurs in the base region and the operation approaches that of an ideal double cantilever structure. When operated as a three terminal filter device an asymmetrical response characteristic is obtained with a pole of attenuation on one side of the passband or the other. This pole can be placed on either side of the passband. In addition, this pole can be moved arbitrarily close to the passband. An equivalent circuit is presented which explains both of these features. A 2000 cps filter can be mounted in a package which is 0.25" in diameter and 0.62" long, has a volume of 0.03 cubic inches, and weighs only 0.01 ounces. A 200 cps filter would be about 1.8" long. Typical response curves will be presented showing 6 db bandwidths of about 4% and minimum power insertion losses ranging from 3 to 8 db. With minor modifications these piezo-electric tuning forks can be used as resonant reed relays which require 100, 000 times less power than magnetic resonant reed relays. In addition, piezoelectric resonant reed relays offer substantial savings in size and weight as well as immunity to stray magnetic fields. Both the filters and the resonant reed relays are made from a filter ceramic whose temperature dependence and aging characteristics have proven satisfactory in a wide variety of commercial and military applications.