CA2598754A1

CA2598754A1 - Failure resistant ceramic polymer capacitor

Info

Publication number: CA2598754A1
Application number: CA 2598754
Authority: CA
Inventors: David A. Kelly
Original assignee: Individual
Current assignee: Individual
Priority date: 2006-10-06
Filing date: 2007-08-21
Publication date: 2008-04-06

Abstract

A failure resistant capacitor, using ceramic polymer as the dielectric in a capacitor structure.
The capacitor is made using at least one failure resistant electrode forming one polarity of electrode in capacitor. The dielectric layers separating the electrodes are composed at least partly of a high K
ceramic material with a polymer binding agent. Each layer of the capacitor has an electrode on one side of a dielectric layer, which is then assembled such that there is at least one alternating failure resistant electrode with at least one dielectric layer separating an adjacent opposite polarity electrode. The failure resistant electrode is designed to be capable of disconnecting a defect in the dielectric layer from the rest of the capacitor structure. Alternately, the capacitor may be constructed with an electrode structure that limits the energy discharged through a defect in the dielectric layer to an amount predefined by the electrode construction. The dielectric layer is composed of a ceramic polymer dielectric which is supported by a carrier layer forming part of the capacitor electrode structure.

Description

FIELD OF THE INVENTION
The field of the invention relates to a capacitor construction where at least part of the dielectric consists of a high K ceramic material, with special electrodes that are resistant to failure and provide isolation, to predetermined amount, of capacitor defects from electrical circuits external to the capacitor. The dielectric layer is a ceramic polymer mixture principally composed of a high K
ceramic. The resistant to failure electrode structure is well suited to capacitors specifically designed for high energy density and energy storage.

BACKGROUND OF THE INVENTION
Traditionally, batteries of many different types and construction has filled the role of electric energy storage devices, but they suffer from a limited life and a slow rate of recharge. The development and demand by the public for pure electric or hybrid cars, electric scooters and renewable energy sources such as solar or wind power has created the need for an inexpensive, long lived, fast to recharge electric storage device. The development of various super capacitor technologies has tried to fill the need for such an electrical device. Each of the various super capacitor technologies developed have specific technical limits to their operation. Lower cost super capacitor designs are constantly being researched with the goal of developing and meeting the public's requirement for such an inexpensive device.
Various industries require the continued development of inexpensive capacitors and electric energy storage devices using high K dielectric materials, where 'K' refers to the dielectric constant.
For example research into Relaxor Ferro-Electric ceramics, has lead to the discovery of materials with properties that are well suited for use in a capacitor, with dielectric constants up to 100,000 but, a number of the most promising materials are not compatible with current ceramic capacitor manufacturing technology. Further, problems have been recognized with existing ceramic super capacitor technology such represented by US7,033,406, where a short circuit across a dielectric layer between oppositely charged electrodes results in sudden destruction of the capacitor and at times the destruction of the capacitor assembly being used as an ESU (Energy Storage Unit).
Another problem with ceramic capacitors is the development of internal cracks, across the dielectric insulating layers, caused by thermal shock, impurity, voltage surge, mechanical stress from improper handling and the manufacturing process. These cracks and defects represent weak spots within the dielectric insulating layer, often the location where an electrical short circuit develops during normal operation. To reduce the risk of an electrical short circuit manufacturers have to substantially increase the thickness of the dielectric layer making the ceramic capacitor larger and more expensive than a failure resistant capacitor structure would require.
A ceramic super capacitor energy storage device, manufactured using the traditional ceramic capacitor method of construction, often uses hundreds of capacitors connected in a parallel arrangement, with each capacitor having tens to hundreds of insulating dielectric layers. This means that each energy storage device contains tens of thousands of insulating dielectric layers where a short in a single layer would result in the discharge of the whole energy storage device into a single capacitor, often destroying the capacitor.

To reduce the threat of destruction of a ceramic super capacitor energy storage device, by such a common failure mode, the addition of external current limiting or fuse element to each capacitor or group of capacitors is required. The purpose of the fuse device is to disconnect the failed capacitor from the energy storage device in such a way that the energy storage device will continue to function, even though one or more elements have failed. The use of thick dielectric layers in a ceramic super capacitor in addition to external fuse devices increase the size and expense of an energy storage device using conventional design practices.
Polymer film capacitors of current manufacture are relatively mature, efficiently utilize available dielectric material, are low cost to manufacture and may be designed to be failure resistant, such that an internal dielectric short circuit clears in such a manner that the capacitor continues to function as intended. The mechanical and electrical performance of polymer film capacitors are ideal in all ways except the dielectric constant of polymer film is only 1/2000 that of a high K
ceramic material.
There are many different patents that provide information about current state of the art in capacitor design and manufacture such as US 6,426,861 for polymer, US6,544,651 for ceramic polymer and US 7,027,288 for ceramic. US7,033,406 is an example of an ESU
(Electrical Storage Unit) that uses state of the art ceramic capacitor technology in its manufacture. The ceramic capacitor used in the ESU have no mention of fuse elements or other electrode technology to provide a degree of failure resistance. The capacitor design relies on a void free ceramic glass matrix where the structure is about 10% by volume a special glass. The absence of any form of failure resistant or fuse element in the ceramic structure makes the capacitor at risk of melting or become severely damaged, should a dielectric layer fail. The use of ceramic glass composite matrix improves some properties but still leaves the capacitor sensitive to cracking if subjected to mechanical stress.
US4, 247,881, 7,027,288 and 7,099,141 demonstrate two different methods of failure resistance, should an insulating dielectric layer fail. For polymer capacitors, failure resistant design practices are represented by US4,049,859, 4,131,931, 4,433,359 and 4,685,026.
An example of a method used to increase the power capability of a cylindrical polymer film capacitor is represented in US4,719,539. US6,426,861 is a good example of a hybrid film capacitor where one or more polymer materials are blended together to form the dielectric layer.

SUMMARY OF THE INVENTION
The present invention provides a new capacitor construction and method of manufacture where the insulating dielectric material is composed principally of a ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound, where the ceramic powder comprises up to 95% by volume, of the resulting electrically insulating dielectric matrix. The polymer compound for example may be based on an epoxy, silicone, polyurethane, polyamide etc. base, using either addition or thermal cure to change from a liquid to solid phase. The polymer compound often uses many types of additives to slow the cure process, solvents to reduce the viscosity of the ceramic polymer mixture, adhesion promoters to improve the bonding strength of the polymer to the ceramic particles and substrate.
Another aspect of the invention where an electrically insulating dielectric layer is composed principally of a ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound, where the ceramic powder comprises up to 95% by volume, is subjected to heat and pressure, perpendicular to the plane of the electrodes during the curing process of the polymer compound, where after the curing process has completed remaining voids have been removed or contain gas at a high pressure, increasing the remaining void breakdown voltage.
Yet another aspect of the invention where a capacitor electrically insulating dielectric layer is composed principally of a ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound, where the polymer compound is a soft elastic compound such as a silicone gel, acrylic or other adhesive that adheres to the ceramic powder after curing.
An aspect of the invention where an electrically insulating dielectric layer is composed principally of a ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound, where the polymer compound is diluted with a solvent compatible with both the ceramic powder and polymer compound to make the electrically dielectric insulating material easier to form into layers during manufacture and the solvent is evaporated from the solid matrix during the manufacturing process.
An aspect of the invention where an electrically insulating dielectric layer is composed principally of a ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound, where: the electrically insulating dielectric material is stacked with alternating electrode layers, where a number if not all the electrodes are connected to one of at least two common electrodes located on different sides of the capacitor, and each common electrode is electrically isolated from each other and comprise one polarity of a capacitor.
In specific embodiments of the invention, applied to the new method of capacitor construction, the electrically insulating dielectric layer between opposite polarity electrode layers, is broken into at least two intermediate insulating layers, where each intermediate insulating layer has an isolated floating electrode, such that a short or failure of one intermediate insulating layer doesn't create a short circuit through the whole insulating dielectric structure. The breaking up of a single electrically insulating layer into multiple intermediate layers provides a form of failure resistance for the capacitor so long as the remaining electrically insulating dielectric layer(s) is capable of carrying the full voltage applied across it. The advantage of this specific embodiment is applicable to capacitors operating at high voltages and will allow the thickness of the dielectric layers to decrease, reducing size, manufacturing cost and improve the reliability of the capacitor.
Other specific embodiments of the invention, applied to the new method of capacitor construction, where an electrically insulating dielectric layer is composed of any amount of ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound using special electrode construction as required to meet the requirements of the intended application.

Another object of the present invention is to substitute a ceramic polymer dielectric in place of the polymer dielectric used in polymer (plastic) film capacitors. This provides a ceramic polymer capacitor method of manufacture that is inexpensive, failure resistant and offers energy densities up to 1000 times that of conventional polymer film capacitors, of a similar physical size. The method of manufacture is compatible with all ceramic dielectric compounds including those that are currently not compatible with conventional ceramic capacitor fabrication methods. The method of manufacture resolves the many problems encountered when high densities of ceramic dielectric powder are combined with a polymer compound to form an insulating dielectric layer. A capacitor designed and fabricated using the present invention is capable of exceeding the energy densities of current ceramic capacitor technology and through the use of new high K
ceramics, currently not useable in conventional ceramic capacitors, may be capable of exceeding the energy density of the best storage battery technology. A capacitor manufactured according to the current invention can be constructed to have any desired electrical performance and environmental capabilities of current ceramic or polymer film capacitor technology.

The dielectric used by the preferred embodiment is comprised of a suitable ceramic powder, often comprised of but not limited to 2 predominant sized particles typically 1 micron in diameter or less, where the smaller particles are no more than 1/2 the size of the larger particles. The ceramic powder is dried then combined with a polymer compound that includes a compatible solvent and other selected additives to adjust the viscosity and impart desired properties to the mixture. The percentage by volume of ceramic to polymer, after removal of the solvent, is up to 95%. The polymer compound is activated so it can be cured during a later process stage.
The mixture is processed to remove residue gasses, moisture or other undesired substances.
The resulting ceramic polymer solvent mixture is then applied to a substrate or previous capacitor layer, using any process that provides the desired film thickness and properties. The solvent is then sufficiently removed to leave the ceramic polymer mixture with properties that are compatible with the next step in the capacitor manufacturing process.
In preferred embodiment the substrate is a thin polymer film, which has the desired electrode structure already, deposited on its surface. The substrate with the ceramic polymer compound, less solvent is then either wound onto a cylindrical form if the desired capacitor is to be round and axial or layered onto a suitable substrate to be later cut into a rectangular or other desired shape.
In the preferred embodiment the capacitor structure is completed; then a voltage that has AC
and DC components, that are specific to the ceramic polymer mixture, is applied for a predetermined time across the capacitor electrical terminations, often with increased atmospheric pressure to enhance the dielectric and electrical properties of the capacitor and finally the polymer portion of the capacitor is often cured with the same AC and DC applied voltage, often through the application of a predetermined temperature.
Yet another aspect of the invention where a capacitor electrically insulating dielectric layer is composed principally of a ceramic dielectric powder, typically smaller than 1 micron in size, bound together into a void free solid matrix with a polymer compound, where the polymer compound is a soft elastic compound such as a silicone gel, acrylic or other adhesive that adheres to the ceramic powder after curing.

In the preferred embodiment of the invention where an electrically insulating dielectric layer is composed principally of a ceramic dielectric powder, bound together into a void free solid matrix with a polymer compound, where: the electrically insulating ceramic polymer dielectric material is formed on a thin polymer film substrate with at least one electrode layer deposited on its surface.
The electrode is often I to 1000 ohm per square aluminum or other suitable alloy, 10's of angstroms thick. During normal operation of the capacitor occasionally weak sections of the dielectric layer may arc or short. The energy of the dielectric short circuit converts the very thin aluminum or suitable alloy in the area of the arc into an electrical insulator which then acts to isolate the failed section of dielectric from the undamaged parts of the capacitor. This clearing action is a form of self-repair, commonly referred to as a "failure resistant capacitor". The ability of the ceramic polymer dielectric capacitor to self-heal in the preferred embodiment allows the use of much thinner ceramic polymer dielectric layers than possible in convention ceramic capacitor manufacturing, making the capacitor smaller and less expensive to manufacture.
In specific embodiments of the invention, applied to the new method of capacitor construction, the electrically insulating dielectric layer between opposite polarity electrode layers, is broken into at least two intermediate insulating layers, where each intermediate insulating layer has an isolated floating electrode, such that a short or failure of one intermediate insulating layer doesn't create a short circuit through the whole insulating dielectric structure. The breaking up of a single electrically insulating layer into multiple intermediate layers provides a form of failure resistance for the capacitor so long as the remaining electrically insulating dielectric layer(s) is capable of carrying the full voltage applied across it. The advantage of this specific embodiment is applicable to capacitors operating at high voltages and will allow the thickness of the dielectric layers to decrease, reducing size, manufacturing cost and improve the reliability of the capacitor.
In yet another embodiment the isolated floating electrode in an axial capacitor is broken into segments, all of which are located on the same capacitor layer, between the electrodes. This separates the dielectric into many different sections such that a short circuit to one floating electrode leaves the remaining floating electrodes unaffected.

In other embodiments the floating electrically isolated electrode is often 1 to 1000 ohm of a suitable alloy, often aluminum, 10's of angstroms thick. During normal operation of the capacitor occasionally weak sections of the dielectric layer may arc or short to the floating electrode. The energy of the dielectric short circuit converts the very thin aluminum in the area of the arc into an electrical insulator, which then acts to isolate the failed section of dielectric from the undamaged parts of the capacitor. This clearing action is a form of self-repair, commonly referred to as a "failure resistant capacitor".

In another specific embodiment of the invention, the axial capacitor layers are wound on a hollow structure. The hollow structure allows the passage of a coolant, such as air to pass through the middle of the capacitor, cooling the inner layers. The additional cooling of the inner layers allows the capacitor to dissipate greater amounts of heat, allowing the operation at higher power levels.
In yet another specific embodiment of the invention, the axial capacitor layers are wound on a thermally conductive solid structure. The thermally conductive structure allows the removal of heat from the middle of the capacitor, cooling the inner layers. The additional cooling of the inner layers allows the capacitor to dissipate greater amounts of heat, allowing the operation at higher power levels.

BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a number of different PRIOR ART capacitor electrode structures;
FIG. 2 represents commonly used PRIOR ART alternating arrangement of dielectric and electrode layers in a capacitor;
FIG. 3 represents PRIOR ART, a failure resistant alternating arrangement of dielectric and electrode layers in a capacitor;
FIG. 4 represents PRIOR ART, another failure resistant alternating arrangement of dielectric and electrode layers in a capacitor;
FIG. 5 represents various capacitor electrode configurations of the present invention;
FIG. 6 provides a number of cross-section views of capacitor structures represented by the present invention;
FIG. 7 represents how electrodes are formed on a carrier film or substrate;
FIG. 8 represents another method of electrode structure formed on a carrier film or substrate;
FIG. 9 provides yet another method of electrode structure formed on a carrier film or substrate;
FIG. 10 depicts an axial capacitor construction of the present invention;
FIG. 11A represents a ceramic polymer composition;
FIG. 1lB represents the ceramic polymer after it is conditioned by applying an appropriate voltage, prior to curing;
FIG. 12 represents the ceramic polymer dielectric constant as a function of percent ceramic;
FIG. 13 represents the ceramic polymer breakdown voltage as a function of percent ceramic;

DETAILED DESCRIPTION OF THE INVENTION
The preferred embodiment, not shown in any figure, in accordance with the present invention is the fabrication of a capacitor dielectric layer, using a mixture consisting of a high K
ceramic powder typically 1 micron in diameter or less, polymer compound with curing agent, compatible solvent and other additives to modify the viscosity to the desired value and improve adhesion of the polymer to the ceramic powder and substrate. Typically but not limited to, the dielectric has up to 95% high K ceramic material by volume. The polymer agent fills any voids that may be present and acts like an adhesive to bind the ceramic material together and to neighbouring layers with it often having elastic properties throughout the life of the capacitor. During capacitor manufacture solvent is removed from the dielectric layer(s) as well as trapped gas. Appropriate pressure, process temperature, voltage of predetermined amplitude, frequency and time are applied after the capacitor is assembled and during the curing process.
The polymer compound for example may be based on an epoxy, silicone, polyester, polyurethane, polyamide etc. base, using either an addition or thermal cure to change it from a liquid to solid phase. The polymer compound often uses additives to slow the cure process, solvents to reduce the viscosity of the ceramic polymer mixture, adhesion promoters to improve the bonding strength of the polymer to the ceramic particles and substrate. Compounds or additives that disperse the ceramic particles throughout the polymer are not desirable in the preferred embodiment if the intention is to use the Winslow Effect to enhance the final properties of the dielectric in the capacitor.
The dielectric made in this preferred embodiment has polymer content often more than 5%
by volume, bonds to the ceramic particles with an electrical breakdown no less than the ceramic powder and has high corona resistance. If a dielectric failure should occur the polymer compound in conjunction with the ceramic powered do not evolve high volumes of free gas but chemically react forming an electrically insulating, inert solid with a similar volume to the original ceramic polymer mixture.
The side views in all FIGURES are greatly exaggerated for clarity where dielectrics are 1 to 10's of microns thick, the thicker layers used for higher working voltages and the electrode is typically 0.01 to 1 micron thick.

The embodiment in FIG. 1 shows PRIOR ART electrode structures which were often screen printed on green ceramic layers, prior to firing. Alternately, the electrodes were screen printed or directly onto ceramic polymer dielectrics. Some of the various electrode structures that are used in combination each other to form various types of capacitors , some of which offer a degree of failure resistance. In FIG. 1 numbers 100, 103, 107, 110, 115, 120, 130 and 140 represent different layers that maybe used in a ceramic polymer and conventional ceramic capacitor construction. Layer 100 is shown with both a top and a side view of the structure, where 101 represents a dielectric material of ceramic or ceramic polymer construction with electrode 102 formed on the dielectric with no outside electrical connection. Layer 103 is shown in both a top and side view of the structure, where 105 represents a dielectric material of ceramic or ceramic polymer construction with two isolated electrodes 104,106 shown exaggerated in thickness. The electrodes are often formed by screen-printing, spraying or any other suitable method of deposition directly on the dielectric with both electrodes having separate outside electrical connections. Layer 107 is shown in both a top view and side view of the structure, where 109 represent a dielectric material of ceramic or ceramic polymer construction with an isolated electrode 108 formed as before, on the dielectric with an outside electrical connection. Layer 115 is shown in both a top view and side view of the structure, where 117 represents a dielectric material of ceramic or ceramic polymer construction with an electrode 116 formed, as described before, on the dielectric with an outside electrical connection. Substrate 110 is shown in both a top view and side view of the structure, where 112 represents a substrate of material which a capacitor stack may be formed on top of, where the substrate is typically a ceramic or ceramic polymer construction with electrically isolated electrodes 111 and 113 formed on top and around the substrate ends. Electrodes 111, 113 provide an electrical connection to the capacitor electrodes, in the above electrode layers and with an external electrical circuit. FIG. 1 reference 150 shows a greatly exaggerated section of electrode that is used to further increase the resistance of the electrode, made from PTC or other material. The electrode convolutions are often only a few microns in width with the spaces similar in dimension. The thin convoluted sections increase the resistance of the electrode, improve voltage-blocking capability and facilitate fusing of the electrode, if the electrode is made from a fusible material. This example shows 2 convoluted sections in parallel which may in practice be any number from none and up. Reference 120 shows the convoluted section 122 being placed in the middle of a floating electrode, splitting it into two parts 121 and 123. Reference 130 and 140 places the convoluted section 131 and 141 respectively at the electrode end just prior to the part making connection outside of the structure.
FIG. 2 is a typical PRIOR ART ceramic polymer capacitor construction, where 205 are individual conductive surfaces connecting the individual electrodes 203 one side and 202 the opposite polarity electrodes to their respective end electrodes 200 and 204.
Where 201 is the dielectric material. This structure is made up using FIG.1 layers 107, 115 and 110. Where in prior art preferred embodiments at least one electrode is made from a high resistance 1 kilo to 1 Mega ohm per square material often with PTC characteristics using electrode structures such as FIG.1 130 and 140.
FIG. 3 is PRIOR ART of a type of failure resistant capacitor construction where 306 are individual conductive surfaces connecting the individual electrodes 303 one side and 302 the opposite polarity electrodes to their respective end electrodes 300 and 305.
Where 301 is the dielectric material. At least one floating electrode 304 is placed between every other electrode 302 and 303. The floating electrode divides the dielectric layer into two parts, such that a failure in one part leaves the remaining part to support the voltage between electrodes 302 and 303. Normally electrodes 304 are at half the potential of 302 and 303 but if one of the dielectric layers fails the remaining dielectric layer will support the voltage difference between electrodes 302 and 304.
Additional layers of isolated floating electrode 304 may be used to further divide the dielectric structure into smaller sections. This structure is made up using FIG.1 layers 100, 107, 115 and 110.
Where in prior art preferred embodiments at least one electrode is made from a high resistance 1 kilo to 1 Mega ohm per square material often with PTC characteristics using electrode structures such as FIG. 1 120, 130 and 140.
FIG. 4 is PRIOR ART of a failure resistant capacitor construction where 406 are individual conductive surfaces connecting the individual electrodes 401 one side and 402 the opposite polarity electrodes to their respective end electrodes 400 and 405. Where 403 is the dielectric material. One electrode 404 is placed between every other electrode 401 and 402 and prevents a hard short circuit in the event of a dielectric layer failure, so that normally, the electrodes 404 are at half the potential of 401 and 402 but if one dielectric layer shorts the remaining dielectric layer will hold off the potential difference between electrodes 401 and 402. This structure is made up using FIG.1 layer 100, 103 and 110. Where in prior art preferred embodiments at least one electrode is made from a high resistance 1 kilo to 1 Mega ohm per square material often with PTC
characteristics using electrode structures such as FIG. 1 120, 130 and 140.
One preferred embodiment of the invention is a ceramic polymer capacitor design that is lower cost to manufacture and smaller in size to an equivalent polymer film capacitor. The insulating dielectric of the preferred embodiment is comprised of a suitable ceramic powder, often comprised of two different size ceramic particles both typically 1 micron in diameter or less, where the smaller particles are no more than 1/2 the size of the larger ones. This ceramic powder is then combined with a suitable polymer compound that includes a compatible solvent and other selected additives to adjust the viscosity and impart desired properties to the mixture. The polymer compound is activated for curing during a later process stage. The mixture is then processed to remove any residue gases, moisture or other undesired substance. The resulting ceramic polymer mixture is then applied using a suitable process to a substrate. The solvent is adequately removed to leave the ceramic polymer mixture with properties that are compatible with the next step in the capacitor process. In a preferred embodiment the substrate is a thin polymer film that has the desired electrode structure already applied. The thin polymer substrate with the ceramic polymer dielectric is then either wound in a round or oval cylindrical form if the desired capacitor is to be axial or alternately layered onto a substrate to be cut later into a rectangular or other desired shape. In a preferred embodiment the capacitor structure is completed; then AC and DC
voltage that are specific to the mixture is applied across the capacitor terminals to enhance the electrical properties of the dielectric through the Winslow Effect, with pressure further to enhance the dielectric properties and compresses voids with heat applied at a point in the process to cure the polymer mix. This forms the final structure and if necessary completing the curing process of the polymer compound. Following the final fabrication process the capacitor has a combination of AC and DC
voltage applied to the electrodes. It is electrically processed following a predetermined process under appropriate environmental conditions, to determine if it meets the requirements of the type and voltage of capacitor being manufactured. This completes the capacitor fabrication process.
The resulting ceramic polymer dielectric, made in this preferred embodiment has a polymer content as low as 5% by volume, is often selected to have elastic properties and adheres well to the ceramic particles with high corona resistance. During dielectric failure the polymer compound in conjunction with the ceramic powder do not evolve high volumes of free gas but chemically react into an electrically insulating, inert solid with volume similar to the original ceramic polymer mixture.
The dimensions in figures 5 through 11 are greatly exaggerated and not in any way to scale for purposes of clarity. In actual practice the ceramic polymer dielectrics are typically only 0.2 to 10s of microns and the electrodes often a few 10s of angstroms and the ceramic polymer carrier layer 5 to 50 microns thick.
FIG. 5 represents the most common but not all electrode structures that are formed on the polymer carrier, which the ceramic polymer dielectric compound is later applied to. Many different types of carrier substrates are compatible with the fabrication of ceramic polymer layers. Polymer (often referred to as plastic) films are used in the preferred embodiment.
In FIG. 5, number 500 represents an internal electrode, electrically isolated from the outside, which is commonly used in a failure resistant capacitor. It is often used in conjunction with electrode 503 forming a structure such as that found in FIG. 6D. In FIG. 5, 502 has 1 to 1000 ohm per square resistance often a few lOs angstroms thick, fabricated from suitable alloy, often aluminum but may be any electrically conductive material even with PTC
properties, that when subjected to the energy of an internal short circuit, turns into an electrical insulator. 501 represents the carrier film that has a break down voltage no less than the working voltage of the capacitor as it is subjected to voltage during, and often after, a capacitor internal short clearing process. Further the thickness must be adequate to withstand the mechanical stress of forming the ceramic polymer coating on its surface. Electrode 503 is used often in conjunction with electrode 500 to form a structure as that found in FIG. 6D. Number 504 is the left capacitor conductive electrode and 506 form the opposite or right capacitor electrode. Both electrode 504 and 506 are designed such that electrical connection may be made to them from outside the capacitor. In FIG.
5, 505 is the carrier substrate film and does not have to be any thicker, often 5 to 50 micron, sufficient to support the ceramic polymer forming process.
Electrode 503 alone is often used to form a capacitor structure similar to FIG. 6D if first a ceramic polymer layer of suitable material and thickness is formed on the electrode surface, then an electrically isolated conductive layer is formed on top, over lapping both the right and left electrode areas. Next another suitable ceramic polymer layer would have to be formed on top. The carrier substrates are then stacked on top of each other to form an alternating capacitor structure.
FIG. 5, 507 is carrier substrate where 509 is the electrically insulating layer and 508 the electrode, often aluminum, typically a few 10s of angstroms thick with the ability to form an outside electrical connection. Carrier substrate reference 507 is subjected to low voltage stress and only thick enough to survive the formation of the ceramic polymer layer on top of it. In FIG. 5 reference 515 is identical to 507 except reversed, 516 represent the electrodes that facilitate the forming of an external electrical connection to the capacitor electrode and 517 the electrically insulating substrate layer, subjected to low voltage stress and the mechanical stress from the formation of the ceramic polymer layer on its surface. Electrodes 507 and 515 in FIG. 5 are often used to form capacitor structures like those in FIG. 6A and C. The conductive surfaces 508 and 517 are often made of but not limited to aluminum 0.01 to 1 ohm per square, when 507 and 515 are used in a capacitor structure represented by FIG. 6C.
In FIG. 5 electrode 520 offers the capability of failure resistance and is the simplest capacitor construction. Reference 524 is a floating electrode with no outside electrical connection, often 1 to 1000 ohms per square a few 10s of angstroms, often aluminum and when subjected to the energy of an arc converts into an electrically insulating material, extinguishing the arc. 521 is the carrier substrate, often a polymer film that is of adequate thickness to withstand the full working voltage of the capacitor and the mechanical stress of forming a ceramic polymer layer on top. Electrode 524 is often used to make a failure resistant capacitor structure such as that in FIG. 6E.
FIG. 5, 510 represents a base substrate that if often used when a rectangular capacitor structure is desired. Item 511 is the left electrode connection, 513 the right and 512 is the substrate itself, which is often but not limited to ceramic. Substrate 510 is present in capacitor structures shown by FIG. 6, A through F.
FIG. 6 represents various capacitor cross sections used by a number of embodiments of the invention. All figures 6A, B, C, D, E and F use the preferred embodiment ceramic polymer dielectric and fabrication steps for assembly of the finished capacitor structure. FIG. 6A is formed by applying a layer of ceramic polymer to the topside of FIG. 5 reference 507 and 515 electrodes.
They are placed in alternating layers such that the right electrodes of one polarity are separated by at least one ceramic polymer layer from the left polarity electrodes, which form the other half of the capacitor. Reference 600 and 605 are the substrates for the capacitor, which are often ceramic if a hard durable material is required for a printed circuit board surface mount capacitor. Item 603 are the left electrodes, 602 the right ones and 601 the ceramic polymer dielectric. The end electrical connections 604 and 606 make electrical contact to each of the electrical electrodes 602 and 603 respectively; formed by any of the methods commonly used in the manufacture of polymer film capacitors. To make the structure failure resistant electrodes 603 and 602 are 1 to 1000 ohms per square often a few 10s angstroms of aluminum.
FIG. 6B is similar to A except only one carrier film is used with the left and right conductive electrode on opposite sides providing a simpler design where the ceramic polymer is often applied as a layer to one side and the layers stacked together until the desired capacitance value is achieved.
Though FIG. 6B is simpler in construction the carrier substrate has to withstand the full working voltage of the capacitor, which is not a requirement in FIG. 6A. This is not a problem for low voltage capacitors but becomes less economical for high voltage capacitors, which preferably use FIG. 6A, C, D or F for lower cost and the smallest size. In FIG. 6 B, 620 and 625 are the end substrates, 621 the ceramic polymer, 622 the carrier film with opposite polarity electrodes, 623 and 624 are the end electrical connections made using any compatible process used by the manufacture of polymer film capacitors. To make the structure failure resistant, electrodes on the carrier film reference 622 must be often 1 to 1000 ohms per square a few 10s angstroms of aluminum or other suitable alloy.

FIG. 6C is a structure that requires more process steps but has the highest impulse current capability of any design, still having a degree of failure resistance.
Alternating two different carrier films assembles the capacitor. The first electrode 632 is formed by applying at least one ceramic polymer layer followed by the application of an externally isolated floating electrode 634 of 1 to 1000 ohms per square material that forms an electrically insulating material if it is involved in a dielectric short circuit between capacitor layers. Different processes often form the isolated electrode, such as but not limited to inkjet printing, spraying, screen printing, evaporation and sputtering. The isolated electrode is followed by at least one additional layer of ceramic polymer.
More than one isolated electrode 634 may be used not shown, to further increase the failure resistance capability, where each isolated electrode is followed by at least one layer of ceramic polymer dielectric compound. The whole process is repeated for opposite electrode structure 633.
The two different electrode layers are laid on top of each other building up the structure until the desired capacitance value is achieved. In FIG. 6C, 630 and 637 form the capacitor support substrates, 631 is the ceramic polymer dielectric material, 632 and 633 the electrode structures often thin foil 0.01 to 10 ohm per square resistance for high impulse current capability, 635 and 636 are the electrical connections made to the capacitor electrodes in the same manner as FIG. 6A.
FIG. 6D is another design that has superior failure resistance capability relative to 6B, though more complex often more expensive to manufacture. FIG. 6D is formed by two different carrier films 641 and 644, where each film has at least one layer of ceramic polymer dielectric applied before they are laid on top of the previous layer. The structure uses electrodes FIG. 5, 500 and 503. In FIG. 6D, 640 and 646 are the substrates the capacitor is assembled on, 641 the external electrodes often but not limited to 1 to 1000 ohm of aluminum a few 10s angstroms thick, 642 is the ceramic polymer dielectric and 643 and 645 the end electrical connections made to the electrodes in the same manner as in FIG. 6A. The ceramic polymer dielectric and capacitor electrode carrier films do not carry any electrical voltage and only need to be thick enough to survive the stress of forming the ceramic polymer dielectric layers on top of them.

FIG. 6E is a low cost design well suited for low voltage ceramic polymer capacitors, where the carrier film is required to block the working voltage of the capacitor.
The electrodes are often deposited directly on the carrier film as shown in FIG. 5, 520. They are 1 to 1000 ohm often aluminum a few lOs of angstrom thick and posses a degree of failure resistance if a short circuit should occur across the ceramic polymer dielectric. The capacitor is made by forming at least one layer of ceramic polymer dielectric of the desired thickness on top of the carrier film. The films are then stacked until the desired capacitance value is achieved. In FIG. 6E, 650 and 655 are the substrates that support the capacitor structure, item 651 has both the left and right electrodes in addition to serving as a carrier film for the ceramic polymer dielectric. End terminations 643 and 645 are the electrical connections formed in the same manner as in FIG. 6A.
FIG. 6F is an electrode configuration well suited to the construction of high voltage capacitors often greater than 1 kilo-volt. The capacitor uses a number of intermediate floating electrodes that are coupled through common dielectric layers. The net effect is to make a capacitor that is a number of individual capacitors stacked in series with only one set of external electrodes.
The reason for making a capacitor in this manner rather than use a much thicker dielectric layer is that research has found that the blocking capability of an insulating layer is not directly proportional to thickness but decreases substantially the thicker it is made. Secondly, with a number of individual capacitors in series there are more intermediate layers to block the voltage between the end electrodes, should a single layer fail. Finally, the voltage applied across a defect is only that available in a single capacitor rather than the total across the capacitor itself, greatly reducing the heating of the defective area. In FIG. 6F 660 and 670 represent the substrate the capacitor is assembled on. The left output electrode is 661 and right is 667 with 665 and 663 the respective conductive layer that joins all the common output electrodes together.
Reference 664 are the intermediate floating electrodes and in this example the final capacitor is actually equivalent to 4 capacitors connected in series. Ideally this structure is often fabricated from a continuous sheet such as that shown in FIG. 7, where the sheet is slit at twice the normal width.
The carrier films in figures 7, 8 and 9 are often made using a polymer that is used in conventional polymer film capacitor construction. FIG. 7 shows the capacitor electrode structure formed on a continuous carrier film. The sheet as shown is designed to simultaneously manufacture a number of capacitors using an electrode structure similar to FIG. 5, 520 and FIG. 6E. In FIG. 7, 706 is the top layer of the film, 711 the bottom layer and 720 a cross section of one strip. The ceramic polymer dielectric would be formed on the top surface prior to slitting or cutting the film into sections along reference lines 700. The explanation of each element is as follows, 704 represent the edge margin of the film to be discarded. Item 702 would be a capacitor electrode, 703 the opposite electrode, both make electrical connection outside of the structure and are electrically isolated from each other by area 705. Lines 701, 707, 710 and 714 represent the fact that the sheet is continuous and only a small segment is shown. Item 713 is the area on the bottom of the sheet that is free of any conductive film. Areas 712, all are hatched and represent areas that are electrically conductive, often 1 to 1000 ohm aluminum a few 10's of angstroms thick, but have no outside electrical connection as the conductive area is well back from the cut lines.
The electrode layer on the underside is segmented into isolated areas of a specific size. The purpose is to limit any permanent dielectric short circuit to a small area of the capacitor.
Additionally, this limits the energy released during the dielectric short circuit to a predetermined level and if the fault is not cleared, only a small portion of remaining ceramic polymer is subjected to higher operating voltage. The segmenting of the inner electrode is predominately used only on capacitors with large amounts of stored energy, providing a further level of protection, improving capacitor reliability. The extra protection allows higher voltage stress to be applied to the ceramic polymer without affecting production yield or product reliability, making the capacitor smaller and lowering cost. Item 720 is a cross section of the carrier film where 721 is the left electrode, 722 the right electrode both of which have outside electrical connections. Item 724 is the electrically isolated inner electrode and 723 represents the electrically insulating carrier layer. The carrier layer as shown is a design that would often be used to manufacture an axial style of capacitor. To make a stacked version the top electrodes require horizontal zones along the horizontal cut lines, that are free of conductive film and would appear similar to the bottom layer except the conductive films would be in line with the existing top strips and the end result, when cut into individual electrodes, look similar to FIG. 5, 520. The electrode films are often 1 to 1000 ohm per square, often aluminum a few lOs of angstroms thick, deposited in any manner that provides an electrically conductive film with the desired properties. Alloys other than aluminum may be used but they should form an electrically insulating material after the dielectric short circuit has cleared.
FIG. 8 represents a variation of the carrier film pattern used in the construction of the capacitor structure FIG. 6D, where the isolated inner electrode is either a separate carrier film of electrode type FIG. 5, 500 or printed directly on the ceramic polymer layer.
The whole structure is constructed using the method explained and shown in FIG. 6C. In FIG. 8, 806 is the top layer, 811 the bottom layer, 800 the slit lines for separation after manufacture. Area 804 and 814 are the edge keep back zone, discarded during manufacture, 802 and 812 an electrode, with 803 and 813 the opposite electrode. Item 820 represents a cross section of the film, 821 and 824 the left electrode, 822 and 825 the right and 823 the support or structure carrier layer that is not subjected to high voltage stress, but must withstand the mechanical stress of forming one or more ceramic polymer layers on top before assembly. FIG. 8 represents a continuous film structure often used in the manufacture of an axial capacitor. To use the film for a stacked capacitor design as represented by FIG. 6C or 6D then horizontal strips free of conductive film would have to be present and would look similar to that shown in FIG. 7, 712, except shifted to be inline with the vertical slit lines 800.
The end result would be an electrode similar to FIG. 5, 503. The conductive films are often 1 to 1000 ohm aluminum a few 10s of angstroms thick, deposited in any manner that provides a conductive film of the desired properties. Alloys other than aluminum may be used but they should form an electrically insulating material after the dielectric arc has cleared.

FIG. 9 represents another variation of carrier film pattern that may be used in the construction of the capacitor structure FIG. 6B. In FIG. 9, 906 is the top layer, 911 the bottom layer, 900 the slit lines for separation after manufacture. Item 904 and 914 are the edge keep back zone, discarded during manufacture, 902 the left electrode, with 912 the right electrode located on the bottom layer. Item 920 represents a cross section of the film, 921 the left electrode, 925 the right with 923 the dielectric layer that is subjected to voltage stress equal to that across the ceramic polymer dielectric and must withstand the mechanical stress of forming one or more ceramic polymer layers on top of it before assembly. FIG. 9 represents a continuous film structure typically used in the manufacture of an axial capacitor. To use the film for a stacked design as explained and shown in FIG. 6B, then horizontal strips free of conductive film would have to be present and would look similar to that shown in FIG. 7 reference 712, except shifted to be inline with the vertical slit lines 900. The end result would be an electrode similar to FIG. 5, 507, except the upper electrode of the pair 508 would have its electrical connection to the left instead of right. This capacitor structure would often be used for capacitors under 500 volts and represents a simple low cost method of manufacture. The electrode electrically conductive films are often 1 to 1000 ohm aluminum a few lOs of angstroms thick, deposited in any manner that provides a conductive film of the desired properties. Alloys other than aluminum may be used but they should form an electrically insulating material after the dielectric arc has cleared.

Figures 7, 8 and 9 has demonstrates the method of fabricating a continuous sheet form of three electrode structures from FIG. 5 for use in the manufacture of ceramic polymer axial capacitors. Other styles of electrode carrier sheets may be designed following similar design philosophy. Wider sheets and alternative electrode patterns used in polymer film capacitors find use as carrier sheets compatible with the manufacture of ceramic polymer capacitors.
FIG. 10 represents the design of a round, axial style ceramic polymer capacitor. Oval and flat axial capacitors may be made either by winding the layers, starting with an oval or flat form alternately, compressing a round capacitor into a form or mold. A number of different layers make up its construction. Item 956 represents the capacitor body as the layers 950 through 955 are wound on it. Item 957 is the structure the capacitor is wound on to and in this example a hollow structure is shown. By constructing the capacitor with a hollow core air or a coolant can be circulated through the middle to cool the inner layers. This allows the capacitor to be operated at much higher power dissipation. Yet another aspect of the invention uses a solid core. Lead 958 is one electrical connection and 962 the opposite, both of which are connected to the left and right capacitor electrodes respectively. The external electrical connections 958 and 962 are joined through connections 959 and 961 respectively to the inner electrodes through similar processes such as electrode spraying used by polymer film capacitor manufacture. Item 960 represents the outer insulating and protective layer of the axial capacitor. Layers 950 through 955 are required in varying numbers by different capacitor structures.
For example to construct an axial capacitor with a layered structure such as in FIG. 6D, layer 950 becomes the left and right electrode (FIG. 5-503, sheet FIG. 8) with a ceramic polymer layer deposited on top. Layer 951 is 1 to 1000 ohm per square, often aluminum 10s of angstrom thick.
Failure resistant isolated electrode FIG. 5-500, for which a continuous sheet could be fabricated with a ceramic polymer layer on top. Layers 952, 953, 954 and 955 are not used.
Layers 950 and 951 are then wound together on the capacitor body 956 until the required capacitance value is reached.
The simplest axial capacitor is formed following FIG. 6E using a single layer 950 which has electrode FIG. 5-520 deposited on it, with a single ceramic polymer layer on top and layers 951 through 955 unused.
The remaining common capacitor structures represented by FIG. 6A through 6F
require a varying number of layers but are wound on the capacitor body in a similar manner to the two provided examples. The carrier films with appropriate electrodes often are designed in a similar method to figures 7, 8 and 9. It is easy to see from the various examples that various capacitor structures can be manufactured similar to those used in the manufacture of polymer film capacitors.

An example of a ceramic polymer capacitor used to test resistance to failure was made as follows:
Ceramic Powder used VLF-312 made by MRA Laboratories Inc.
Silicone with thermal set catalyst 1C55 made by HumiSeal Silicone oil DMST05 and DMSV05 made by Gelest Inc.
Silicone oil VQM-135 made by Gelest Inc.
Xylene, solvent technical grade Floating electrode capacitor carrier film salvaged from 940C30P-15K polymer film capacitor made by Cornell Dulier , similar structure to FIG. 1 - 100 Outer electrode capacitor carrier film salvaged from 940C20W-1K-F polymer film capacitor made by Cornell Dulier, similar structure to FIG. 1 -103 The ceramic polymer mixture consists of 10 gram Xylene, 5.4 gram 1C55, 0.3 gram DMST05, 0.3 gram DMSV05, 5.0 gram VQM-135 and 46.5 gram of VLF-312 previously dried for 1 hour at 300F. Mixture is weighed and then placed into a clean glass container with mixing glass or ceramic spheres. Tumbled the mixture at low rpm for 24 hours until there are no lumps and consistence of paint. Test cure a sample at 120 Celsius for 15 minutes. The useful life of the mixture is about 2 months, though as the thermally activated catalysis in the 1C55 may precipitate or breakdown with the presence of the ceramic and Xylene. The density of the ceramic powder is about 6.3 times that of the silicone which means that 46.5 gram of ceramic is equivalent to the a volume of 7.4 grams of silicone. The ratio of ceramic used in the mixture is 7.4/(7.4 +
11) where 11 is the total weight of all the silicone compounds, 1C55, MMST-05, DMSV-05, VQM-135 which gives about 40%.
The test capacitor was assembled as follows. First capacitor 940C30P-15K was taken apart and the inner floating electrode salvaged and cut into 6 inch long strips and etch off the metal film 1.5" from each end using a concentrated solution of sodium hydroxide. Next capacitor 940C20W-1K-F was dismantled and the left and right electrode metalized film salvaged and cut into 6 inch lengths. Pour a small amount of ceramic polymer mixture in a shallow pan and pass the metal side of the floating electrode over the solution then let hang and dry at least 1 hour. Adding or allowing excess xylene to evaporate to adjust the viscosity as required. Lay the dual electrode, metal up onto a flat surface then lay the floating electrode with ceramic polymer on top.
Roll the strip, while under tension onto 3/8 inch electrically insulating tube. Attach leads using a conductive film such as silver or nickel print. This completes the assembly of the capacitor. It will be found that healing events will occur from low voltage and most samples will block over 1000 volts DC. If you wish to cure the capacitor then it will have to be uniformly heated to over 120 Celsius for 15 minutes. If the ceramic polymer film is left uncured then it is much easier to dismantle the capacitor to study the clearing of defects or thin spots. This capacitor construction is failure resistant. The construction of a capacitor using this technique is only for a person skilled in the art as they would be aware of safety procedures and other lesser steps that have been omitted. The above solution is only marginally compatible with enhancement of the dielectric and voltage properties with application of suitable electric fields described later. This is because the 1C55 is a mixture that is suspected of using dispersing agents, which inhibits the formation of ceramic particle chains.
A common formula for the capacitance between two parallel plates is C = KEoA/d equation 10 where C => the capacitance in Farads K => dielectric constant of the material between the parallel plates so => permittivity of free space, which is 8.854 x 10-12 F/m A => area of the plates in m2 d => the separation of the plates in m Polymer film capacitors have a very low dielectric constant K of 3 to 14 while commonly used ceramic dielectrics have K values of 50 to 30,000 with less common ceramics exhibiting values as high as 100,000. The ratio of the difference in dielectric constants between ceramic materials to polymer film is 17 to 2000 and for less common ceramics as high as 33,000! The voltage breakdown of a ceramic material is potentially equal to that of a polymer film however;
it suffers from a large number of structure defects that greatly reduce the practical working voltage.
Polymer film capacitors do not have as serious structural defect problem and when combined with failure resistant electrodes they are able to operate close to their theoretic break down voltage. Ceramic capacitors have a much greater dielectric constant, are smaller but only 1/30 the size of an equivalent polymer film capacitor, larger by 2 to 3 orders of magnitude than what would be possible if they had a similar fault tolerant electrode structure.

Examining equation 10 it becomes obvious that if a ceramic material were substituted for the polymer in a plastic film capacitor the capacitance value would be substantially increased. If for example a commonly used ceramic dielectric material, known in the electronics industry as XR7 with a K value of 1200 replaced the polymer with a K of 3, leaving the capacitor size and geometry unchanged, the capacitance would be 400 times that of the original polymer capacitor. With the cost of the ceramic material within the same order of magnitude as that of the polymer film, then the substitution of a ceramic material for the polymer would dramatically reduce the size and cost of the capacitor's manufacture by at least 2 orders of magnitude.
FIG. 11A is an example of a ceramic polymer compound that may be used as the dielectric material in a ceramic polymer capacitor. In this example the polymer content is about 40%, exaggerated for purposes of clarity and much larger than the preferred embodiment. In FIG. 11A, 980 and 986 are the capacitor electrodes, 981, 983 including 987 are regions of mostly polymer, which in this example is present near the electrodes. Item 982 and all other hatched areas are the ceramic dielectric material, of which there are shown two predominate sizes the smaller of which is about '/4 the size of the larger. Item 988 is an area where the amount of polymer is about 60% by volume and is partially devoid of ceramic particles. Reference 985 is showing areas where the polymer is very thin between the ceramic particles and parallel to the electrodes.
One problem that FIG. 11A represents is that the ceramic particles often clump together and leave areas, often near the electrodes, devoid of ceramic particles. The polymer compound often has a dielectric value typically 1/1000 that of the ceramic. The isolated areas of only polymer combined with the difference in dielectric constants presents a serious problem most evident when AC is applied across the capacitor electrodes 980 and 986. When AC is applied across the electrodes the ceramic particles appear like a short circuit placing a disproportional large amount of the AC voltage across the polymer in areas such as represented in FIG. 11A by 981, 983, 987.
The concentration of voltage is because the polymer and ceramic particles act like two different capacitors in series with each other. From equation 10, the polymer region with 1/1000 the K value will have 1/1000 the capacitance as a ceramic particle of equal size. The result is two capacitors in series, the polymer capacitor having 1/1000 the capacitance of the ceramic one. When a voltage is applied across the two capacitors in series as in this example approximately 99.9% of the voltage will appear across the smaller value of capacitance in this case the polymer one. This implies that the areas that are polymer rich are subjected to a substantially larger voltage than those which are dense with ceramic particles. The higher voltage across the polymer causes these areas to break down long before the ceramic rich ones. This is a highly simplified explanation and its purpose in not mathematical accurate but greatly simplified to quickly explain why a ceramic polymer dielectric with very high concentrations of high K ceramics are often not able to reliably sustain voltages gradients equal to those of when either the polymer or ceramic are by themselves.

The voltage concentrates across the polymer sections in areas 981, 983 and 987 and as it is increased the dielectric will start to fail either through heating as the polymer is subjected to very high leakage current or ionization avalanche breakdown. Either mechanism of failure produces reaction products such as gas, leading to mechanical deformation of the capacitor structure. The damage often propagates until it extends completely through the ceramic polymer dielectric resulting in a short circuit and the expenditure of a large amount of energy, from the capacitor leads, into a very small volume.
FIG. 13 represents a graph of the break down voltage, under AC bias as a function of the percentage concentration of ceramic particles in the ceramic polymer dielectric. The graph assumes the worst possible circumstance that areas of polymer exist without ceramic particles present. The breakdown often occurs near the electrodes, shown in FIG. 11A item 981, 983 and 987. As the concentration of the ceramic rises, the thickness of the polymer between ceramic particles and the electrode interface region decreases, reducing the polymer's ability to withstand the voltage applied across the capacitor without suffering from either local heating or micro breakdowns. In FIG. 13, item 853 represents the breakdown withstand capability, in percent, of a dielectric layer consisting only of polymer. Item 855 represents the relative breakdown voltage, in percent, for a solid ceramic dielectric layer. Item 854 represents the relative AC voltage blocking ability of the preferred embodiment with a 92% ceramic content, without suffering from localized polymer heating or micro breakdown events. The graph is presented as a representation of the problem and actual results can vary greatly depending on the type of polymer, ceramic particle size and method of fabrication. For the same applied voltage, graph 13 implies that a 90% high K ceramic polymer dielectric may require a much as 10 times the thickness of an equivalent amount of polymer or ceramic dielectric.
FIG. 12 represents the value of the ceramic polymer dielectric constant as the concentration of ceramic is varied. This graph is only a general representation and actual results may vary greatly depending on the method of fabrication, type of polymer used, special additives to prevent particle clumping and ceramic particle size. Item 850 represents the dielectric constant that results if there was no ceramic powder present and 852 is the value as if it was 100% ceramic.
From this graph it is seen that to achieve a high dielectric value the amount of ceramic present has be very high.
However, FIG. 13 shows that as the ceramic content is increased the ceramic polymer dielectric breakdown voltage decreases.

Using the information from figures 11A and B, 12 and 13 methods of enhancing the properties of the ceramic polymer dielectric were developed for a preferred embodiment of the invention to reduce if not eliminate the problem of lower voltage capability and reduced dielectric constant. The special processing allows the use of much thinner ceramic polymer dielectric layers.
The preferred embodiment uses various manufacturing processes to shift the dielectric constant in FIG. 12 along reference line 851 to a value nearly the same as point 852, as if the polymer had been removed from in-between the ceramic particles. The result is a higher dielectric constant and greatly improved value of AC voltage breakdown. The preferred embodiment manufacturing process shifts the break down voltage from the point FIG. 13, 854 along line 856 to a value close to if not to 855.
The effect is as if the polymer was removed from between the ceramic particles, increasing the voltage breakdown of the ceramic polymer dielectric. However, this last claim assumes that the polymer has at least similar if not the same voltage break down value as the ceramic else the final value will be closer to the lesser of the two.

FIG. 11B shows how the dielectric would look after processing the dielectric with AC and DC voltage before the polymer cures. The preferred amplitude, frequency of AC
and DC has to be determined experimentally as it is unique to each ceramic polymer combination.
A technical paper discussing the variations in AC frequencies required to get the ceramic particles to form together into chains and clumps between the electrodes is 'An Investigation of assembly conditions of dielectric particles in uncured thermoset polymer, ' by C. P Bowen et al;
Journal Materials Research, Vol. 9, No. 3, Mar. 1994 . A number of ceramic particles are the same in both FIG. 11A
and FIG. 11B. What has taken place is the ceramic particles have been drawn together tightly, excluding the polymer from around the gains as much as possible and are tight against the electrodes. The problems of FIG. 11A have been eliminated with areas of polymer and ceramic separated; in such a way that the dielectric is able to withstand higher voltage than if the ceramic and polymer were randomly clumped together. References 991, 993, 997 show ceramic in tight proximity to the electrodes. Reference 998 shows a region of straight polymer that was excluded from the more densely packed ceramic particles. There will always be some small areas of polymer such as shown by 994 within the ceramic but these voids will be small and the ceramic particles will partially shunt the electric field lines around them, improving the voltage blocking capability. For this effect to properly take place then the ceramic polymer mixture should not have any additives that have the property of a dispersant on the ceramic particles. Dispersants are only added to a mixture only if clumping of the ceramic together in the aforementioned way is not desired.
In one preferred embodiment the manufacturing process is controlled to minimize the amount of polymer, such that only the small voids are filled around the ceramic particles. This is achieved by combining ceramic powders of greatly differing sizes reducing the amount of void space that the polymer has to occupy. This is evident from FIG. 11B, in the areas where the ceramic particles are of differing sizes and very dense, the area around the ceramic particles require only very small amounts of polymer to fill the voids. The actual amount of polymer required is dependent on the size of ceramic particles and method of mixing. Very dense areas of ceramic particles do not suffer from a substantially lowered voltage blocking capability as would be expected with a ceramic polymer dielectric with a much higher percentage of polymer than the minimal amount.
The clumping together into strings of solid particles in-between two electrodes when an electric field is applied; is called the 'Winslow Effect', which is the behavior of an electrorheological fluid. In the preferred embodiment this type of fluid exists when the ceramic particles are in solution with an uncured polymer, with or without solvent present. For best results a dispersing agent is not added to the mixture. Two technical papers discussing the Winslow Effect are 'Advances in modeling in the mechanisms and rheology of electrorheological fluids' by Howard See, Korea-Australia Rheology Journal, Vol. 11, No.3, September 1999 pp. 169-195 and 'Dynamic simulation of an electrorheological fluid' by R.T. Bonnecaze and J.F. Brady, Department of Chemical Engineering, California Institute of Technology, Pasadena California.
The process used by the preferred embodiment is the application of an electric field across the ceramic polymer dielectric layer before the polymer is cured. The application of a voltage, an experimentally determined combination of AC and DC across the ceramic polymer dielectric layer will produce the Winslow Effect. The ceramic particles will form chains and clumps between the electrodes as in FIG. 11B. The Winslow Effect will replace any polymer in undesirable areas, such as the electrodes with ceramic particles. In some embodiments a further improvement in the dielectric constant of some ceramic dielectric materials will occur if an appropriate type of electric field is applied across the ceramic polymer solvent mixture immediately after it is applied to the carrier substrate. In other embodiments an electric field is applied to the carrier film immediately after application of the ceramic polymer solvent mixture in addition to the capacitor after assembly but before the polymer is fully cured.

Another manufacturing process of the preferred embodiment, that increases the voltage blocking capability of the ceramic polymer is to apply AC voltages of low frequencies often greater than 1 Hz, slowly increased in amplitude and frequency to over heat and break down the polymer areas that are weak due to defects in the manufacturing process. The triggering or use of the capacitor's failure resistant capability will disconnect the defective areas internally from the rest of the capacitor, in a controlled manner. The recording of the number of healing events during the product test will determine whether the ceramic polymer dielectric layer meets the final product reliability requirement and will identify capacitors of low quality through their high number of defects.

A final process of the preferred embodiment that improves the reliability and product yield during capacitor manufacture is to use a number of isolated floating electrodes, with failure resistant properties, such as in the capacitor design represented by FIG. 6C. The use of this technique is common in high voltage polymer film capacitors and is equally applicable to capacitors using ceramic polymer dielectrics.

Although the invention has been described in connection with a preferred embodiment, it should be understood that various modifications, additions and alterations may be made to the invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.

Claims

1. A multi-layer ceramic polymer capacitor comprising; and a) ceramic polymer is deposited on polymer sheet that has a first electrode structure already deposited on its surface, to form dielectric volumes and dielectric surfaces;
and b) ceramic polymer is deposited on a second polymer sheet that has a second electrode structure already deposited on its surface, to form second set of dielectric volumes and dielectric surfaces;
and c) the first and second sheets are then combined forming an alternating structure of first polymer carrier sheet with one electrode structure with external electrical connection followed by a ceramic polymer dielectric layer, next a second polymer carrier sheet with a second electrode with external electrical connection, then another ceramic polymer dielectric layer; and d) the structure is repeated in said sequence until the desired number of layers have been formed;
and e) where the first electrodes are electrically connected together to form one polarity of a capacitor;
and f) the second electrodes are electrically connected together to form a second polarity of a capacitor and are electrically isolated from the first electrodes.
g) the ceramic polymer dielectric compound is then cured.

2. As in claim 1 except the electrodes are made of a aluminium 10's of angstroms thick and turns into an inert electrically isolating material when subjected to the energy of a short circuit.

3. As in claim 1 except the electrodes are made of a suitable alloy 10's of angstroms thick and turns into an inert electrically isolating material when subjected to the energy of a short circuit.

4. As in claim 1 except a previously determined combination of AC and DC
voltage is applied for a specific time prior to curing of the ceramic polymer mixture which is unique to the ceramic polymer compound and during the curing process to enhance both the electrical withstand capability and value of dielectric constant of the final capacitor.

5. As in claim 4 where no additives are added for the specific purpose of dispersing the ceramic particles throughout the ceramic polymer mixture.

6. As in claim 1 where the structure is not stacked in layers but two sheets one with the first electrode structure on it and a layer of ceramic polymer compound on top and a second sheet with the second electrode structure with ceramic polymer mixture on top are continuously wound on a form to produce the final desired value of capacitance where the structure is layered in the same sequence and the first electrode has an external electrical connection made to it and the second electrode as a separate external electrically isolated from the first connection and all other processing steps remain the same.

7. A multi-layer ceramic polymer capacitor comprising; and a) ceramic polymer is deposited, to form dielectric volumes and dielectric surfaces, on top of a polymer sheet that has a first electrode structure already deposited on the top of its surface and a second electrode structure deposited on the underside of it surface; and c) multiple sheets are then combined forming an alternating structure of first polymer carrier sheet followed by the first top electrode structure with external electrical connection, followed by a ceramic polymer dielectric layer, next the bottom layer second electrode with an external electrical connection on the next polymer carrier sheet then the polymer carrier sheet, the first electrode structure on the top of the sheet followed by a ceramic polymer dielectric layer; and d) the structure is repeated in said sequence until the desired number of layers have been formed;
and e) where the first electrodes are electrically connected together to form one polarity of a capacitor;
and f) the second electrodes are electrically connected together to form a second polarity of a capacitor and are electrically isolated from the first electrodes.
g) the ceramic polymer dielectric compound is then cured.

8. As in claim 7 except the electrodes are made of a aluminium 10's of angstroms thick and turns into an inert electrically isolating material when subjected to the energy of a short circuit.

9. As in claim 7 except the electrodes are made of a suitable alloy 10's of angstroms thick and turns into an inert electrically isolating material when subjected to the energy of a short circuit.

10. As in claim 7 except a previously determined combination of AC and DC
voltage is applied for a specific time prior to curing of the ceramic polymer mixture which is unique to the ceramic polymer compound and during the curing process to enhance both the electrical withstand capability and value of dielectric constant of the final capacitor.

11. As in claim 10 where no additives are specifically added for the specific purpose of dispersing the ceramic particles throughout the ceramic polymer mixture.

12. As in claim 7 where the structure is not stacked in layers but the sheet is continuously wound with ceramic polymer compound on top onto a form to produce the final desired value of capacitance where the structure is layered in the same sequence and the first electrode has an external electrical connection made to it and the second electrode as a separate external electrically isolated from the first connection and all other processing steps remain the same.

13. A multi-layer ceramic polymer capacitor comprising; and a) ceramic polymer is deposited, to form dielectric volumes and dielectric surfaces, on top of a polymer sheet that has a first electrode structure and a second electrode structure electrically isolated from each other already deposited on the top of its surface and on the underside of it surface already deposited a third electrically isolated floating electrode structure that over laps both the first and second electrodes; and c) multiple sheets are then combined forming an alternating structure of first polymer carrier sheet followed by the first electrode structure with external electrical connection and the second electrode structure with an external electrical connection, followed by a ceramic polymer dielectric layer, next the bottom layer with floating third electrode externally isolated structure on the next polymer carrier sheet then the polymer carrier sheet, followed by the first electrode structure with external electrical connection and the second electrode structure with an external electrical connection, followed by a ceramic polymer dielectric layer,; and d) the structure is repeated in said sequence until the desired number of layers have been formed;
and e) where the first electrodes are electrically connected together to form one polarity of a capacitor;
and f) the second electrodes are electrically connected together to form a second polarity of a capacitor and are electrically isolated from the first electrodes.
g) the ceramic polymer dielectric compound is then cured.

14. As in claim 13 except the electrodes are made of a aluminium 10's of angstroms thick and turns into an inert electrically isolating material when subjected to the energy of a short circuit.

15. As in claim 13 except the electrodes are made of a suitable alloy 10's of angstroms thick and turns into an inert electrically isolating material when subjected to the energy of a short circuit.

16. As in claim 13 except a previously determined combination of AC and DC
voltage is applied for a specific time prior to curing of the ceramic polymer mixture which is unique to the ceramic polymer compound and during the curing process to enhance both the electrical withstand capability and value of dielectric constant of the final capacitor.

17. As in claim 16 where no additives are specifically added for the specific purpose of dispersing the ceramic particles throughout the ceramic polymer mixture.

18. As in claim 13 except there are multiple over lapping floating, electrically isolated electrode structures such that their overlapping combine to form four or more separate capacitors, between the first and second electrodes, internally combined in series to increase the working voltage of the capacitor.

19. As in claim 13 where the structure is not stacked in layers but the sheet is continuously wound on a form to produce the final desired value of capacitance where the structure is layered in the same sequence and the first electrode has an external electrical connection made to it and the second electrode as a separate external electrically isolated from the first connection and all other processing steps remain the same.

20. As in claim 6 the sheet is continuously wound onto a hollow core to better allow the cooling of the inner capacitor layers.

21. As in claim 12 the sheet is continuously wound onto a hollow core to better allow the cooling of the inner capacitor layers.

22. As in claim 19 the sheet is continuously wound onto a hollow core to better allow the cooling of the inner capacitor layers.

23. As in claim 6 the sheet is continuously wound onto a solid thermally conductive core to better allow the cooling of the inner capacitor layers.

24. As in claim 12 the sheet is continuously wound onto a solid thermally conductive core to better allow the cooling of the inner capacitor layers.

25. As in claim 19 the sheet is continuously wound onto a solid thermally conductive core to better allow the cooling of the inner capacitor layers.

26. As in claim 6 except a previously determined combination of AC and DC
voltage is applied for a specific time prior to curing of the ceramic polymer mixture which is unique to the ceramic polymer compound and during the curing process to enhance both the electrical withstand capability and value of dielectric constant of the final capacitor.

27. As in claim 12 except a previously determined combination of AC and DC
voltage is applied for a specific time prior to curing of the ceramic polymer mixture which is unique to the ceramic polymer compound and during the curing process to enhance both the electrical withstand capability and value of dielectric constant of the final capacitor.

28. As in claim 19 except a previously determined combination of AC and DC
voltage is applied for a specific time prior to curing of the ceramic polymer mixture which is unique to the ceramic polymer compound and during the curing process to enhance both the electrical withstand capability and value of dielectric constant of the final capacitor.

29. As in claim 1 the ceramic powder used in the manufacture of the ceramic polymer compound is composed of more than 1 particle size to allow higher densities of ceramic to be used.

30. As in claim 7 the ceramic powder used in the manufacture of the ceramic polymer compound is composed of more than 1 particle size to allow higher densities of ceramic to be used.

31. As in claim 13 the ceramic powder used in the manufacture of the ceramic polymer compound is composed of more than 1 particle size to allow higher densities of ceramic to be used.