Patent Application
20200185133
The present invention relates generally to electrical transient material and methods for making electrical transient material. More particularly, the present invention relates voltage variable material (VVM) and methods for making VVM.
Electrical transients produce high electric fields and usually high peak power that can render circuits or the highly sensitive electrical components in the circuits, temporarily or permanently non-functional. Electrical transients can include transient voltages capable of interrupting circuit operation or destroying the circuit outright. Electrical transients may arise, for example, from an electromagnetic pulse, an electrostatic discharge, lightning, a build-up of static electricity or be induced by the operation of other electronic or electrical components. An electrical transient can rise to its maximum amplitude in sub-nanosecond to microsecond times and have repeating amplitude peaks.
Materials exist for the protection against electrical transients, which are designed to respond very rapidly, ideally before the transient wave reaches its peak, to reduce the transmitted voltage to a much lower value for the duration of the electrical transients. Electrical transient materials are characterized by high electrical resistance values at low or normal operating voltages. In response to an electrical transient, the materials switch very rapidly to a low electrical resistance state. When the electrical transient dissipates, these materials return to their high resistance state. Electrical transient materials also recover very rapidly to their original high resistance value upon dissipation of the electrical transient.
Electrical transient material or VVM may be used in conventional circuit protection devices. Conventionally, electrical transient materials and VVM's exhibit a trigger voltage (VT) and a clamping voltage (VC). Specifically, electrical transient materials and VVM's trigger or change from a high impedance state to a low impedance state at the VT, which is less than a maximum surge voltage. At some time duration after the VT, the electrical transient materials or VVM's reach a steady VC. Eventually, the voltage due to an electrostatic discharge event will taper from the VC to zero.
In general, it is desirable for electrical transient materials and VVM's to possess low VT and VC values. For example, as the demand for smaller devices and integrated circuits that operate at low voltage and power levels increases, the necessity to provide electrical transient materials and VVM's that trigger and clamp at low voltage levels elevates. However, materials used in electrical transient materials and VVM's have limited further reduction of the VT and VC values.
Given the above-described properties and advantages of electrical transient materials and VVM's, a need exists to continue to develop improved electrical transient materials and VVM's.
Electrical transient materials and voltage variable material (VVM's) are described. Methods for providing such electrical transient materials and VVM's are also disclosed.
In some implementations, an apparatus includes an electrical transient material; and conductive particles disposed in the electrical transient material, at least one or more of the conductive particles have an irregular shape.
In further implementations, a method, includes providing an electrical transient material; and disposing conductive particles in the electrical transient material, at least one or more of the conductive particles have an irregular shape.
In yet further implementations, an apparatus includes an electrical transient material; and conductive particles disposed in the electrical transient material, at least one or more of the conductive particles have an irregular shape, wherein a width of the electrical transient material is between 0.6-1 mil or 15.2-24.4 μm, and the electrical transient material has a voltage peak voltage density of 8.2-4.9, defined as voltage peak/width in μm, and wherein the voltage peak is 125-130 V and the width is 15.2-24.4 μm.
Circuit protection devices and apparatuses may employ electrical transient material (e.g., voltage variable material (VVM)). In some implementations, the electrical transient material includes a binder material. The binder material may include therein a mixture of conductive and semi conductive particles. Furthermore, the binder material may include therein a mixture of insulative particles or nonconductive particles. In another example, the electrical transient material includes a binder material that comprises conductive and semi conductive particles. At least some of the conductive and semi conductive particles may be coated with an insulative oxide film, nitride, silicon, or another one or more inorganic insulating coating.
At least one implementation of the electrical transient material includes conductive particles that have an irregular shape. In one implementation, the electrical transient material includes conductive particles that have an irregular shape and nonconductive particles that have a shape with a boundary that is generally rounded. For example, the nonconductive particles may be circular, oval, or the like. In one implementation, the conductive particles that have an irregular shape have at least one boundary surface or outer surface that is not rounded. For example, the conductive particles that have an irregular shape may have at least one boundary surface, outer surface, or side that is a straight line. In another example, the conductive particles that have an irregular shape may have at least a plurality of boundary surfaces, outer surfaces, or sides that are a straight line.
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The use of conductive particles 204 that have an irregular shape provides several advantages. Specifically, the conductive particles 204 having irregular shapes enhance conduction between the conductive particles 204, compared to conventional conductive particles that are spherical and/or ovalized. In particular, the flat or straight surface(s) of the conductive particles 204 enhance the tunneling effect through the base material 202. For example, in one implementation, the flat or straight surface(s) of the conductive particles 204 may allow the conductive particles 204 to be disposed in close proximity to one another within the base material 202. This close proximity arrangement of the conductive particles 204 may enhance the tunneling effect through the base material 202. The enhanced tunneling effect achieved by the conductive particles 204 having irregular shapes provides lower VT and VC, compared to VT and VC associated with conventional electrical transient materials. Electrical transient materials and VVM's trigger or change from a high impedance state to a low impedance state at the VT, which is less than a maximum surge voltage. At some time duration (e.g, in ns) after the VT, the electrical transient materials or VVM's reach a steady VC. In one implementation, a steady VC reached at 25 ns or around 25 ns. Eventually, the voltage due to an electrostatic discharge event will taper from the VC to zero.
In various implementations, the electrical transient material 102 exhibits a VT in the range of 125-130 V. Furthermore, in various implementations, the electrical transient material 102 exhibits a VC in the range of 70-90 V. In one implementation, the electrical transient material 102 has a width of between 0.6-1 mil or 15.2-24.4 μm, and the electrical transient material has a voltage trigger voltage density of 8.2-4.9, defined as VT/width in μm, and wherein the VT is 125-130 V and the width is 15.2-24.4 μm. Correspondingly, the electrical transient material 102 has a clamping voltage density of 4.6-2.8, defined as VC/width in μm, and wherein the VC is 70-90 V and the width is 15.2-24.4 μm.
At block 304, the electrical transient material is formed to a desired shape and thickness. In one embodiment, the electrical transient material is applied to a rigid surface, such as a conductive substrate or a plate. For example, the electrical transient material in paste form may be applied to the rigid surface. In another example, the electrical transient material in ink form may be sprayed, printed, spin coated or casted onto the rigid surface. In one example, electrical transient material in ink form may be applied to the rigid surface using an application blade. In one implementation, the electrical may be structured by way of compression using a press or roll press to achieve a desired thickness of the electrical transient material. In another implementation, the electrical transient material in ink form may be structured using an application blade (e.g., Doctor Blade) to achieve a desired thickness of the electrical transient material. In one or more embodiments, the process of forming the electrical transient material may include providing one or more electrically conductive surface over a surface or surfaces of the electrical transient material.
At block 306, the formed electrical transient material is allowed to harden by drying, if necessary as part of the process of forming the electrical transient material. In one implementation, the formed electrical transient material is hardened in an oven.
While electrical transient material and a method for manufacturing electrical transient material have been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the spirit and scope of the claims of the application. Other modifications may be made to adapt a particular situation or material to the teachings disclosed above without departing from the scope of the claims. Therefore, the claims should not be construed as being limited to any one of the particular embodiments disclosed, but to any embodiments that fall within the scope of the claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2017/083453 | 5/8/2017 | WO | 00 |
