Patent Application
20050146413
The present invention relates generally to integrated electronic components and, more particularly, to integrated electronic elements that provide adjustable electrical characteristics.
The fabrication of electrical devices, such as resistors, capacitors, and inductors, in integrated devices is well known. Typically, integrated electrical devices are formed by embedding appropriate materials in a substrate. The resulting integrated electrical device typically has relatively fixed electrical characteristics. However, in many applications, the electrical characteristics of such devices must be varied, depending upon the requirements of the given application, including feedback from the output or other circuit requirements to vary the electrical characteristics. Thus, a number of techniques have been proposed or suggested for varying the electrical characteristics of integrated electrical devices in order to maintain the electrical characteristics within specified limits. U.S. Pat. No. 5,543,765, for example, discloses electronic elements having variable electrical characteristics. The electronic elements include a cavity in which a moving insulator element shifts. The moving insulator element is partially covered with an electrically conductive material. An electrical field shifts the moving element to thereby vary the electrical characteristics of the electronic element.
While such proposed techniques may provide a mechanism for maintaining electrical characteristics within a specified range, they often have power or surface area requirements (or both) that are not practical within the constraints of commercially viable integrated devices. A need therefore exists for improved techniques for varying the electrical characteristics of integrated electrical devices in both real time and/or with a feedback. mechanism
Generally, electrical devices having tunable electrical characteristics are provided, such as variable resistors, capacitors and inductors. The tunable electrical characteristics are achieved by placing an appropriate material between substrate layers and by controllably applying a pressure to the material to compress the material or alter the shape of a well in which the material is contained, and thereby alter the electrical characteristics of the electrical device. The composition, shape and dimension of the embedded materials determine how the electrical characteristics of the electrical device are altered upon compression of the embedded material in response to an applied control signal. Generally, as the embedded material is compressed, the material will become more dense and the electrical characteristics of the integrated electrical device are altered.
A more complete understanding of the present invention, as well as further features and advantages of the present invention, will be obtained by reference to the following detailed description and drawings.
The pressure plates 150 will selectively compress the embedded material 110 upon application of an appropriate control signal 160 to the pressure plates 150. The pressure plates 150 may be embodied, for example, as bimetallic plates, piezo electric plates or plates controlled by a micro-electrical mechanical system (MEMS). The pressure plates 150 are in one position when a first voltage is applied and in a second position when a second voltage is applied. In the exemplary embodiment shown in
According to one aspect of the present invention, the resistance of the integrated device 110 will vary depending on whether the integrated device 110 is in an uncompressed or compressed state, or an intermediate state in between. As shown in
In yet another variation of the present invention, the compression applied by the pressure plates 150 may be done continuously or intermittently. A continuous compression will introduce a different change in the electrical characteristics of the integrated electrical device than the vibration effect caused by an intermittent pressure. The pressure plates 150 may thus be controlled by transducers or similar devices that allow the pressure plates 150 to vibrate at a desired frequency. The shape of cavity in which the material 110 is retained may also be selected to achieve different results.
As previously indicated, a material 110 is placed inside the layers of the substrate 120. As a signal passes through the material 110, a particular electrical characteristic of the integrated device is varied as the material is compressed. In one exemplary implementation of an integrated resistive device 100, the material 110 may be a copper (Cu) paste or silver (Ag) paste. The resistance material can be mixed with Carbon (C) and a suspension compound to keep the finished material in a grease or gel state. The resistance value can be adjusted from 1 ohm up to 1 mega-ohm depending on the formulation. Generally, the material 110 is selected so that the response to the signal and the mechanical action is sufficient to produce the range of variation in the electrical characteristic which is required.
The pressure plates 250 will selectively compress the embedded material 210 upon application of an appropriate control signal 260 to the pressure plates 250. The pressure plates 250 may be embodied, for example, as bimetallic plates, piezo electric plates or plates controlled by a micro-electrical mechanical system (MEMS). The pressure plates 250 are in one position when a first voltage is applied and in a second position when a second voltage is applied. In the exemplary embodiment shown in
According to another aspect of the present invention, the capacitance of the integrated device 220 will vary depending on whether the integrated device 220 is in an uncompressed or compressed state, or an intermediate state in between. As shown in
In yet another variation of the present invention, the compression applied by the pressure plates 250 may be done continuously or intermittently. A continuous compression will introduce a different change in the electrical characteristics of the integrated electrical device than the vibration effect caused by an intermittent pressure. The pressure plates 250 may thus be controlled by transducers or similar devices that allow the pressure plates 250 to vibrate at a desired frequency. The shape of cavity in which the material 210 is retained may also be selected to achieve different results.
As previously indicated, a material 210 is placed inside the layers of the substrate 220. As a signal passes through the material 210, the capacitance of the integrated device is varied as the material is compressed. In one exemplary implementation of an integrated device 200, the material 210 may be comprised of a dielectric material. The dielectric material can be in a grease or gel state. The capacitance value can be adjusted from Picofarads up to microfarads depending on the formulation. Generally, the material 210 is selected so that the response to the signal and the mechanical action is sufficient to produce the range of variation in the capacitance that is required. The capacitance material would be potentially anything from an air gap with parallel plates, ceramic materials, glass, tantalum oxide and different dopants added to Silicon.
In addition to the resistive and capacitive devices 100, 200, discussed above in conjunction with
It is to be understood that the embodiments and variations shown and described herein are merely illustrative of the principles of this invention and that various modifications may be implemented by those skilled in the art without departing from the scope and spirit of the invention.
