Cooling with microwave excited micro-plasma and ions
One embodiment of the present invention uses an actuator, which is actuated by electromagnetic microwave. The actuator is used to generate the micro-plasma and ions. The configurations of actuators may be microstrip lines structure, stripline structure, piping structure, multiplayer traces and electrodes structure, waveguide structure, and cavity structure. The generated micro-plasma and ions will induce a local turbulent gas flow and the flow is to carry the heat away from the surfaces of the heat sink fins. The actuators may be coupled to heat sink fins, heat transferring pipes, cooling fans, and heat sources in varied configurations.
1. Field of the Invention
The present invention relates generally to electronic equipment, and more particularly, to apparatus and methods for cooling electronic devices using microwave excited micro-plasma and ions.
2. Description of the Related Art
Electronic devices may generate significant heat during operation. High temperatures may reduce the lifespan of these devices, and, therefore, the generated heat may need to be dispersed to keep the operating temperature of the electronic devices within acceptable limits.
One commonly used cooling device is heat sink. Heat sinks may be coupled to electronic devices to absorb heat through the heat sink base and disperse the heat through their fins. Conventional methods to disperse the heat through the heat sink fins are natural convection and forced convection. Natural convection is to disperse the heat away from the surfaces of heat sink fins without the aid of external forced fluid pumping through heat sink fins. On the other hand, the forced convection cooling is to pump the fluid to flow through heat sink fins, such as the fans to blow the air through the heat sink fins, and therefore enhance the heat transfer between fins and outside ambient.
With the increasing power density of electronic devices, the pitch or the distance between heat sink fins is becoming smaller, which means more surface area may be used to transport the heat away. However, when the pitch becomes very small, the pressure drop between inlet and outlet of the heat sink fins may become very high, which may results the difficulties to pump the fluid flowing through fins, and as a result, more powerful fans, which consume higher electricity may be needed for the cooling. The invention utilizes microwave excited micro-plasma and ions to induce the gas flow to conduct the convective heat transfer along the heat sink fins and therefore will resolve these issues.
Another consideration of the electronic device cooling is that, due to size concern, the internal space allowed to put cooling fans and other cooling components, may be limited or not permitted. The invention utilizes the microwave excited micro-plasma and ions gas flow to generate the forced convective heat transfer. Therefore the design is able to improve the heat transfer efficiency and to minimize the required space because microwave excited micro-plasma and ions can be very small.
Another aspect of using the invention is to lower the required power of the system fans of electronic devices. The micro-plasma and ions driven gas flow excited by the microwave couple with the heat sink fins will induce the local turbulence gas flow near heat sink surfaces. The local turbulence near the heat sink surface will enhance the heat dissipation so a better cooling is achieved. Therefore the system fan doesn't need to be very powerful and the electricity energy is saved.
Plasma-driven gas flow has been used either to cool articles or to control and modify the fluid dynamics boundary layer on the wings surfaces of the aerodynamic vehicles. For example, U.S. Pat. No. 3,938,345 used the phenomenon of corona discharge, which is one type of plasma, to do the local cooling of an article. U.S. Pat. No. 4,210,847 designed an apparatus for generating an air jet for cooling application. U.S. Pat. No. 5,554,344 had a gas ionization device to do the cooling of zone producing chamber. U.S. Pat. No. 6,796,532 B2 used a plasma discharge to manipulate the boundary layer and the angular locations of its separation points in cross flow planes to control the symmetry or asymmetry of the vortex pattern.
However, none of the above patents are coupled to the heat sink, which is a fundamental apparatus for cooling electronic devices. Hence, what are needed are a method and an apparatus, to couple with heat sink fins to cool down electronic devices efficiently.
SUMMARY OF THE INVENTIONOne embodiment of the present invention provides a microwave excited micro-plasma and ions couple to heat sink fins to induce the gas flow along the heat sink fins. The induced gas flow will remove the heat away from heat sink fin surface and therefore the heat source is cool down.
In one embodiment, the cooling system includes heat sink fins assembly and array of the microwave excited micro-plasma and ions devices. The heat sink fin assembly may be composed by a plurality of straight heat sink fins, a plurality of heat sink pins, or other shapes of fin structure. The micro-plasma and ions devices may be composed with different configurations, such as micro-strips, microwave wave guides, and microwave cavities. The micro-plasma and ions may be excited and generated at different locations inside the heat sink fin assembly.
In one embodiment, the micro-plasma and ions may be excited and generated with microwave cavities, which have slots, holes, or trench on the surface of the microwave wave guide structure. In a further embodiment, the generated micro-plasma and ions will couple and interact with heat sink fins assembly to do the cooling.
In one embodiment, the micro-plasma and ions actuators may be configured by one or several micro-strips. In another embodiment, the configurations of the micro-strips may be varied to gain the maximum electrical field at specific regions to induce micro-plasma and ions.
In one embodiment, the micro-plasma and ions actuators may be composed of microwave wave guides, which have different configurations such as pipe shape, micro-strip shape, rectangular shape, or other shapes. The dielectric layers may couple with microwave wave guides.
In one embodiment, the applied microwave sources to excite and generate the micro-plasma and ions flow may have varied waveforms, frequencies, amplitude, phase shifts, and may be transient.
A better understanding of the present invention may be obtained when the following detailed description is considered in conjunction with the following drawings, in which:
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Furthermore, note that the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not a mandatory sense (i.e., must). The term “include”, and derivations thereof, mean “including, but not limited to”. The term “coupled” means “directly or indirectly connected”.
DETAILED DESCRIPTION OF THE INVENTIONThe invention generally relates to apparatus for cooling electronic devices or packages, such as microprocessor and ASIC. Such systems and methods may be used in a variety of applications. A non-exhaustive list of such applications includes the cooling of: a microprocessor chip, a graphics processor chip, an ASIC chip, a video processor chip, a DSP chip, a memory chip, a hard disk drive, a graphic card, a portable testing electronics, a personal computer system.
Take laptop computer for example, conventional fans use a lot of space and energy. For this reason, the microwave excited micro-plasma and ions cooling represent a way to increase their cooling capacity and make them more reliable and far quieter. Therefore the higher-performance chips that generate too much heat for current laptops can be used.
As used herein “plasma” is an ionized gas, a gas into which sufficient energy is provided to free electrons from atoms or molecules and to allow both species, ions and electrons, to coexist. Plasma is even common here on earth. A plasma is a gas that has been energized to the point that some of the electrons break free from, but travel with, their nucleus. Gases can become plasmas in several ways, but all include pumping the gas with energy. A spark in a gas will create a plasma. A hot gas passing through a big spark will turn the gas stream into a plasma that can be useful. Plasma torches like that are used in industry to cut metals.
As used herein “dielectric” is a substance that is a poor conductor of electricity, but an efficient supporter of electrostatic fields. In practice, most dielectric materials are solid. An important property of a dielectric is its ability to support an electrostatic field while dissipating minimal energy in the form of heat. The lower the dielectric loss (the proportion of energy lost as heat), the more effective is a dielectric material. Another consideration is the dielectric constant, the extent to which a substance concentrates the electrostatic lines of flux. Substances with a low dielectric constant include a perfect vacuum, dry air, and most pure, dry gases such as helium and nitrogen. Materials with moderate dielectric constants include ceramics, distilled water, paper, mica, polyethylene, and glass. Metal oxides, in general, have high dielectric constants.
Similar to
Not limited by the configurations of the
At very high electromagnetic frequencies, the losses due to radiation can be eliminated and the resistive losses can be minimized, by using closed resonant cavities. A cavity resonator stores both magnetic and electric fields, the energy oscillating between the two, losing energy only to the conducting walls if a perfect dielectric fills the space. The resonant frequency of the cavity is determined by the shape of the cavity and the mode, or allowable field distribution, of the electromagnetic energy that the cavity contains. In one embodiment, the micro-plasma and ions may be excited and generated by microwave cavities and varied forms of coupling of the electromagnetic microwave may be utilized.
The micro-plasma and ions cooling actuator 408 may be made of wave guide structure, microwave cavity structure, micro-strip structure, and embedded conductive traces and electrodes. The cooling actuator 408 may couple to heat sink fins at the inlet, at the outlet, at the top, at the bottom, or in the middle of the heat sink fins 407. In one embodiment, all components may couple to a board 410, such as printed circuit board, so the entire device can be made very small. In another embodiment, the actuators may be made in a bulk scale, a micron meter scale, and a nano meter scale. Furthermore, the actuators may be directly manufactured on a silicon chip structure and the actuators may be manufactured with micro-electro-mechanical wafer processing techniques;
Claims
1. A method and apparatus for cooling electronic devices, comprising:
- a microwave excited micro-plasma and ions actuator coupled with cooling heat sink fins assembly to cool down heat sources;
2. The apparatus of claim 1, wherein the actuator involves using an inner cylinder and an outer cylinder, a micro-strip structure, a stripline structure, embedded conductive traces and electrodes, a wave-guide structure, and a cavity structure for the electromagnetic microwave to pass through to ionize the gas;
3. The apparatus of claim 1, wherein the actuators are populated in an array to couple with heat sink fins assembly;
4. The apparatus of claim 1, wherein the actuators are coupled to a heat sink fins assembly at the inlet, at the outlet, at the top, at the bottom, and in the middle of the heat sink fins assembly, to ionize the air;
5. The apparatus of claim 1, wherein the heat sink fins assembly comprising straight fins, pin fins, and irregular shapes fins structure;
6. The apparatus of claim 1, wherein the actuators comprising conductive traces on one side of the dielectric layer, and ground layer on the other side of the dielectric layer; and multiplayer structure which have openings for microwave to generate micro-plasma and ions;
7. The apparatus of claim 1, wherein the actuators comprising openings on the conductive layers, on the wave guide structures, and on the cavity structures; wherein the openings are locations for electromagnetic microwave to ionize the air to induce the ion driven turbulent gas flow;
8. The apparatus of claim 1, wherein the actuators are operable to couple with a fan, a heat pipe, a heat source, and a heat sink fins assembly to generate the micro-plasma and ions;
9. The apparatus of claim 1, wherein the actuators may be made in a micron scale, a nano meter scale, and a bulk scale;
10. The apparatus of claim 1, the actuators may be coupled to a heat sink fins structure, and the actuators may be directly manufactured on a silicon chip structure; and the actuators may be manufactured with micro-electro-mechanical wafer processing techniques;
11. The apparatus of claim 1, wherein the heat source may be a microprocessor, an ASIC chip, a video processor chip, a graphic processor chip, an electronic IC chip, and a power supplier.
Type: Application
Filed: Sep 8, 2008
Publication Date: Mar 12, 2009
Inventor: Chien Ouyang (Sunnyvale, CA)
Application Number: 12/231,936
International Classification: F28F 13/00 (20060101);