Showing papers on "Heat sink published in 1993"

Heat sink for cooling a heat producing element and application

Abstract: A heat sink mounted on a heat producing element for cooling the heat producing element attached on the printed board of the electronic apparatus, having a heat sink body made of a good heat conductive material and a fan assembly installed inside the heat sink body. The heat sink body is efficiently air-cooled by a cooling air generated by the rotation of the fan assembly. The cooling air forcibly cools a base and a fixing wall of the base adjacent to the heat producing element and plate-like radiating fins or a pin-like radiating fins are protruded on the heat sink body to radiate the heat effectively. The position of the fan assembly is at the center of the heat sink body or is at the offset position from the center of the heat sink body. The heat sink of the present invention can be installed in a portable electronic apparatus such as a portable computer.

Apparatus for synthesizing diamond films utilizing an arc plasma

Abstract: There is provided a system for the manufacture of a diamond film. A plasma generator generates a hydrogen atom containing plasma stream into which a hydrocarbon containing gas is fed. The plasma dissociates the hydrocarbon to carbon radicals and carbon which are deposited on a substrate where the carbon crystallizes to a diamond film. The efficiency of the system is increased by heating the hydrogen source gas prior to generation of the plasma. Other means to increase the effectiveness of the system include using a plurality of plasma streams and shaping the plasma stream, A low internal strain, high quality optical film is generated by depositing the carbon on a substrate supported by a heat sink having nonuniform thermal conductivity such that the thermal gradient across the surface of the heat sink is less than about 8° C./centimeter.

Heat sink assembly with thermally-conductive plate for a plurality of integrated circuits on a substrate

Abstract: A heat sink assembly for a multichip module. A thermally conductive plate is bonded to integrated circuit chips on a multichip module by indium solder. The plate in turn is thermally coupled to a heat sink such as finned aluminum by thermal paste. The plate is made of a material such as silicon carbide or copper-tungsten alloy having a relatively low coefficient of expansion to minimize mechanical stress resulting from lateral motion of the chips due to thermal expansion. Relatively low-power chips may be thermally coupled to the plate by thermal paste instead of being bonded by solder.

Simulating the dynamic electrothermal behavior of power electronic circuits and systems

Abstract: The simulator solves for the temperature distribution within the semiconductor devices, packages, and heat sinks (thermal network) as well as the currents and voltages within the electrical network. The thermal network is coupled to the electrical network through the electrothermal models for the semiconductor devices. The electrothermal semiconductor device models calculate the electrical characteristics based on the instantaneous value of the device silicon chip surface temperature and calculate the instantaneous power dissipated as heat within the device. The thermal network describes the flow of heat from the chip surface through the package and heat sink and thus determines the evolution of the chip surface temperature used by the semiconductor device models. The thermal component models for the device silicon chip, packages, and heat sinks are developed by discretizing the nonlinear heat diffusion equation and are represented in component form so that the thermal component models for various packages and heat sinks can be readily connected to one another to form the thermal network. >

Inverter apparatus and method therefor

Abstract: An inverter apparatus having a compact design and a changeable heat sink. The apparatus includes a power module formed in a case having pairs of parallel sides and containing the respective main circuit semiconductor devices for converting an alternating current input into a direct current and then further into an alternating current of variable frequency. The heat sink also has pairs of parallel sides and interfaces with the case in a plane whereon the projections of the sink and the case are coextensive. The apparatus also has a body with pairs of parallel sides that fasten to the case and constitute part of the enclosure of the inverter apparatus. The body, case, heat sink and associated circuit elements have alignment structures that permit easy and reliable disassembly and assembly of the apparatus.

Laser cooling of molecular internal degrees of freedom by a series of shaped pulses

Abstract: Laser cooling of the vibrational motion of a molecule is investigated. The scheme is demonstrated for cooling the vibrational motion on the ground electronic surface of HBr. The radiation drives the excess energy into the excited electronic surface serving as a heat sink. Thermodynamic analysis shows that this cooling mechanism is analogous to a synchronous heat pump where the radiation supplies the power required to extract the heat out of the system. In the demonstration the flow of energy and population from one surface to the other is analyzed and compared to the power consumption from the radiation field. The analysis of the flows shows that the phase of the radiation becomes the active control parameter which promotes the transfer of one quantity and stops the transfer of another. In the cooling process the transfer of energy is promoted simultaneously with the stopping population transfer. The cooling process is defined by the entropy reduction of the ensemble. An analysis based on the second law of thermodynamics shows that the entropy reduction on the ground surface is more than compensated for by the increase in the entropy in the excited surface. It is found that the rate of cooling reduces to zero when the state of the system approaches an energy eigenstate and is therefore a generalization of the third law of thermodynamics. The cooling process is modeled numerically for the HBr molecule by a direct solution of the Liouville von Neuman equation. The density operator is expanded using a Fourier basis. The propagation is done by a polynomial approximation of the evolution operator. A study of the influence of dissipation on the cooling process concludes that the loss of phase coherence between the ground and excited surface will stop the process.

Thermal component models for electro-thermal network simulations

Abstract: A procedure is given for developing thermal component models for electrothermal network simulation. In the new electrothermal network simulation methodology, the simulator solves for the temperature distribution within the semiconductor devices, packages, and heat sinks (thermal network) as well as the currents and voltages within the electrical network. The thermal network is represented as an interconnection of compact thermal component models so that the system designer can readily interchange different thermal components and examine different configurations of the thermal network. To facilitate electrothermal network design, the interconnection of the thermal component models is specified by the user in the same way that the interconnection of the electrical network components is specified. The thermal component models are also parameterized in terms of structural and material parameters so that the details of the heat transport physics are transparent to the user. Examples of electrothermal network simulations are given, and the temperature measurement methods used to validate the thermal component models are described. >

Cooling multi-chip modules using embedded heat pipes

Abstract: A method and apparatus is disclosed for cooling a multi-chip module using embedded heat pipes. Semiconductor chips are disposed into the multi-chip module through cavities in the module substrate. The semiconductor chips engage heat pipes embedded within the substrate. The heat pipes conduct heat away from the semiconductor chips through a heat conductive bonding layer.

Electro-thermal simulation of an IGBT PWM inverter

Abstract: A recently developed electro-thermal network simulation methodology is used to analyze the behavior of a full-bridge, pulse-width-modulated (PWM), voltage-source inverter which uses insulated gate bipolar transistors (IGBTs) as the switching devices. The electro-thermal simulations are performed using the Saber circuit simulator and include the control logic circuitry, the IGBT gate drivers, the physics-based IGBT electro-thermal model, and the thermal network component models for the power device silicon chips, packages, and heat sinks. It is shown that the thermal response of the silicon chip determines the IGBT temperature rise during the device switching cycle. The thermal response of the device TO247 package and silicon chip determines the device temperature rise during a single phase of the 60-Hz sinusoidal output. Also, the thermal response of the heat sink determines the device temperature rise during the system start-up and after load impedance changes. It is also shown that the full electro-thermal analysis is required to accurately describe the power losses and circuit efficiency. >

EMI shielding device

Abstract: Shielding for a socket of an electronics package comprises, a frame (24) with sidewalls (26,30), solder tails (34) along the sidewalls (26,30), resilient cantilever beams (32) for electrically engaging skirts (56) of a heat sink (18), and a retainer (20) having bars (62) covering openings in the heat sink (18) and plates covering cut outs (28) of the shielding device (12).

Self-locking heat sinks for surface mount devices

Abstract: A structure for attaching a heat sink to an electronic package comprising a pin (10) having a compressible point (16), the point being adapted to pass through aligned holes in a heat sink (40) and a printed circuit board (60) so that the point compresses as it passes into two holes and flexes back to an expanded position after it exits the printed circuit board hole opposite the heat sink thereby holding the heat sink to the board with the electronic package (50) therebetween.

Clip-on heat sink

Abstract: A clip-on heat sink assembly includes a spring and electrically-insulating braces. The spring is shaped to fit over a heat sink and a chip carrier package and engage with the braces which support the chip carrier package. The spring holds the heat sink in place and forces the heat sink and the chip carrier package together in order to maintain good thermal contact. An alternative embodiment includes a spring with the braces attached to form one piece.

Heat-generating element cooling device

Abstract: A cooling device mounting a fan unit above a heat sink mounted on a heat-generating element or buried therein, which produces an effective air flow and achieves a uniform cooling action by having the heat sink shown in various shapes. Further, a cooling fan disposed away from the heat sink or to the side of the same is used for effective cooling through an air conduit passage formed by pipes or a cover.

Micro-Temperature Measurements on Semiconductor Laser Mirrors by Reflectance Modulation: A Newly Developed Technique for Laser Characterization

Abstract: Thermoreflectance measurements performed for the first time on laser diode mirrors have supplied a vast amount of novel information. Heating efficiency has been found to depend sensitively on the mirror treatment, the mirror structure design, the geometry of a deposited heat spreader, the type of coupling of the laser to a heat sink, the number of active quantum wells, the type of cladding layer and the strength of lattice disorder at the mirror surfaces. Degradation processes have been observed in real time by continuously monitoring the mirror temperature. Dark line defects formed during laser operation exhibit a temperature gradually increasing with time. The mirrors suffer catastrophic optical damage within seconds after having reached a critical temperature. Temperature maps show a striking localized hot spot within the optical near-field pattern.

Intersecting flow network for a cold plate cooling system

Abstract: A cold plate for cooling electronic modules and devices is disclosed which incorporates an intersecting flow network. The flow network is designed and devised such that flow paths are arranged in a rectilinear fashion surrounding blocks of material which act as heat sinks. Supply conduits and return conduits for supplying and returning cooling fluid are disposed orthogonally to the flow directions within the flow paths and such that each supply channel is circumscribed by a plurality of return channels, and each return channel is circumscribed by a plurality of supply channels. The arrangement of the supply and return channels insures the shortest possible flow path for the cooling fluid thereby insuring maximum cooling efficiency and minimizing and localizing the temperature rise in the cooling fluid during passage from the supply conduit to the return conduit. With a minimum temperature rise of the cooling fluid over a short flow path, conduction in the cold plate insures optimum uniformity of cooling to the electronic components. The components of the cold plate either may be assembled and clamped or may be rigidly affixed to one another by means of either soldering or braising to form the structure defining the flow channels, conduits and manifold connections necessary for the consistent and uniform circulation of the cooling fluid.

Heat pipe type radiation for electronic apparatus

Abstract: A heat pipe type radiator is formed with a cooling plate mounted on an evaporative section of a heat pipe and a flat heat conductive plate mounted on a condenser section Heat-generating electronic components are brought into contact with the cooling plate and a radiation fin molded from a thin plate in a wave form is mounted on both surfaces of the heat conductive plate Other embodiments of the radiation fin include a skived fin formed by skiving a flat plate in an arch form, a pin fin and a wire fin which are composed of and so forth Since each of these fins has the large surface area for heat radiation per unit volume and is small in weight, it is suitable to use for a heat pipe type radiator for an electronic apparatus The heat generated in the electronic components transported to the heat conductive plate through the cooling plate and the heat pipe is radiated from the entire surface of the radiation fin to the ambient air The heat conductive plate is molded in a flat form and, therefore, the heat generated in the electronic components can conduct to the portion most remote from the heat pipe Further, since the radiation fin has a large surface area for heat radiation per unit volume, the heat radiation capability is improved

Microprocessor heat dissipation apparatus for a printed circuit board

Abstract: Operating heat from a computer microprocessor chip mounted on the top side of a printed circuit board is removed therefrom using a heat dissipation assembly including a metal heat transfer plate and a metal heat conductor block. The heat transfer plate is secured to the circuit board and has a first section which underlies the circuit board beneath the microprocessor chip, and a second portion projecting outwardly from an edge of the circuit board and secured to a wall of the metal housing cage of the computer. The metal heat conductor block extends through a complementarily configured opening formed in the circuit board beneath a central portion of the metal underside section of the chip. A top end of the block is bonded to the metal underside of the chip using heat conductive cement, and the bottom end of the block is removably secured to the top side of the first plate portion beneath the printed circuit board by a threaded fastener, a layer of heat conductive grease preferably being disposed between the bottom block end and the first plate portion. Operating heat from the chip is conducted downwardly through the metal block to the heat transfer plate and then through the plate to the metal chassis which serves as a large heat sink. Additionally, heat is dissipated from the plate by convection. This convective heat dissipation is preferably enhanced by securing a cooling fin structure to the second plate portion.

Low profile integrated heat sink and fan assembly

Abstract: A low profile integrated assembly for dissipating heat from an electronic component includes a heat sink having a peripheral envelope, and a self-contained motorized fan unit for generating a flow of air being embedded substantially within the envelope of the heat sink. The heat sink includes a generally flat heat transferring bottom base plate and a multiplicity of elongated heat dissipating fins attached on and extending upwardly from the bottom base plate. The multiplicity of heat dissipating fins define a cavity. The fins include at least a pair of outer fins being spaced from one another and disposed along a pair of opposite sides of the base plate so as to define a pair of opposite sides of the cavity. The fins also include a plurality of inner fins disposed between the pair of spaced outer fins so as to define a bottom of the cavity being spaced above the base plate. The fan unit is disposed in the cavity and spaced above the base plate by being seated upon the inner fins and retained between the outer fins in a tight-fitting engaged relation therewith.

Printed circuit boards and heat sink structures

Abstract: Printed circuit board and heat sink assembly in which heat conductive elements are provided to distribute heat across the board before transferring heat into the heat sink. Also in other structures, heat is conducted directly into a heat sink from surface mount components while bypassing the board.

Two-phase heat-transfer systems

Abstract: Various techniques are disclosed for improving airtight two-phase heat-transfer systems employing a fluid to transfer heat from a heat source to a heat sink while circulating around a fluid circuit, the maximum temperature of the heat sink not exceeding the maximum temperature of the heat source. The properties of those improved systems include (a) maintaining, while the systems are inactive, their internal pressure at a pressure above the saturated-vapor pressure of their heat-transfer fluid; and (b) cooling their internal evaporator surfaces with liquid jets. FIG. 43 illustrates the particular case where a heat-transfer system of the invention is used to cool a piston engine ( 500 ) by rejecting, with a condenser ( 508 ), heat to the ambient air; and where the system includes a heat-transfer fluid pump ( 10 ) and means ( 401-407 ) for achieving the former property.

Method and apparatus for a self contained heat exchanger

Abstract: A self contained heat exchanger useful for reducing the operational temperature of a solid state device utilizing mixtures of two or more coolants within a hermetically sealed chamber or chambers. The present invention includes embodiments that are useful for removing heat from a semiconductor electronic device. The present invention provides a low boiling point coolant that boils at the operational temperatures of the semiconductor devices to agitate a higher boiling point coolant that remains in liquid state. Movement of the higher boiling point coolant is instrumental in uniformly transferring heat from the heat source across metal radiator surfaces due to the excellent surface contact of the heat rich high boiling point liquid. The chamber surface then uniformly radiates the heat into the surroundings. At equilibrium, boiling action of the lower point liquid coolant and condensation on the metal surface create recirculation paths within the present invention that enhances heat transfer. The entire device may rest squarely on top of the semiconductor package and does not require any active mechanical components or external power or maintenance.

Apparatus and method for cooling electronic devices

Abstract: A heat transfer assembly 11 is disclosed for transferring heat from a heat generating electronic device 15 or computer chip to ambient air. The heat transfer assembly 11 is comprised of a heat pipe 20 mounted perpendicular to a heat generating electronic device 15. The heat transfer assembly 11 is designed to provide a mechanically solid support for the bonding of the various heat transfer assembly components and to use circumferentially mounted fins 23 to increase the efficiency of heat transfer away from the electronic devices 15. The heat transfer assembly can function effectively when mounted in any direction. Thermocouples 42 are used to monitor the temperature and efficiency of the heat generating electronic device 15 such that corrective action can be initiated if the device begins to overheat.

High efficiency heat removal system for electric devices and the like

Abstract: A heat removal system employing fluid circulation and vaporization for transferring heat from a primary heat sink to a secondary heat sink where the heat is dissipated into the surrounding air is disclosed. The present invention comprises a primary heat sink coupled to a secondary heat sink via flexible tubing. The primary heat sink is bonded directly to an electric device such as a semiconductor device. As the electric device heats up and thereby heats up the primary heat sink, a liquid coolant within the primary heat sink transfers excess heat via the tubing to the secondary heat sink where the heat is dissipated. The cooled coolant is then returned to the primary heat sink via the flexible tubing.

Apparatus for cooling semiconductor chips in multichip modules

Abstract: A compact, reliable, and efficient cooling system for semiconductor chips is disclosed. In one embodiment, a plurality of semiconductor chips have their active surfaces mounted to a major substrate which provides electrical connections among the chips, and a cooling channel is formed above the major substrate and each chip for conducting a cooling fluid over the back surface of the chips. To increase cooling efficiency, heat sink arrays are formed on the back surfaces of the chips, each array including a plurality of heat conducting elements attached to the back surface. The arrays may be readily and inexpensively constructed with photo-lithography or wire bonding techniques. To control the flow of cooling fluid around the chip edges and to prevent cavitation of the cooling fluid a cavitation and flow control plate disposed at the bottom surface of the cooling channel and formed around the edges of the chips is included. With the increased cooling efficiency, the height of each cooling channel may be substantially reduced to allow close stacking of interconnect substrates for three-dimensional packages and to shorten the vertical communication time between the interconnect substrates.

Low profile fan body with heat transfer characteristics

Abstract: A low profile fan body (20E) for cooling an electronic component has a fan frame (22E) supporting a fan (28E), which is mounted on a fan base (24E) forming a heat sink or heat transfer body. The fan (28E) has a plurality of fan blades (30E) received within a plenum chamber (51E) defined within the heat sink (24E). Each fan blade (30E) defines a first axial edge (31E), a second axial edge (33E) on a substantially opposite side of the blade (30E) relative to the first axial edge (31E), and a radial edge (35E) extending between the first and second axial edges (31E, 33E). The heat sink (24E) defines a base portion (38E) for engaging an exposed surface of the electronic component, and a plurality of heat fins (45E, 49E) spaced relative to each other along the periphery of the heat sink (24E) and defining the plenum chamber (51E). A pressure differential surface (34E) is disposed between the radial edges (35E) of the fan blades (30E) and the fins (45E) for directing air flow in the axial direction of the fan (28E). The radial edges (35E) of a plurality of the fan blades (30E) are at least partially exposed to the adjacent heat fins (45E, 49E) defining a flow path for cooling air across the radial edges (35E) exposed to the heat fins (45E, 49E). The second axial edges (33E) of the fan blades (30E) are located adjacent to and spaced from the base portion (38E) of the heat sink (24E), defining an additional flow path for cooling air between the second axial edges (33E) and the base portion (38E).

Method for making cooling structures for directly cooling an active layer of a semiconductor chip

Abstract: Cooling structure for direct heat transfer between an active layer of a chip in which electric elements are formed and a heat sink are disclosed. The inventive cooling structure consists of a current/voltage supply level, with metal structures and insulation spacers and/or layers, partly covered by an insulation layer and followed by a heat transfer structure. A heat transfer bridge is in thermal connection with the heat transfer structure that provides for heat flux between the inventive cooling structure and the heat sink. The inventive cooling structure of this invention can be used with semiconductor devices and/or with opto-electronic devices.

Apparatus for using an active circuit board as a heat sink

Abstract: An apparatus and method for using a circuit board as a heat sink for another circuit board which effectively draws heat away from the other circuit board while the one circuit board is actively producing its own heat. Since the one circuit board is much larger than the other circuit board, the thermal mass of the one circuit board is great enough to absorb and spread the heat generated by both boards in the presence of forced air cooling. The method includes the steps of mounting a thermal conductivity layer on a predetermined area on the one circuit board and mounting the other circuit board over the area on the one circuit board such that components on an underside of the other circuit board firmly contact the thermal conductivity layer so as to conduct heat from the components through the one circuit board. The method may include additional steps, such as etching the predetermined area of the top surface of the one circuit board to provide a copper planar member, drilling holes through the one circuit board, and filling the holes with a conductive material to form conductive vias linking the copper planar member with a ground planar member within the one circuit board.

Electronic component heat sink attachment using a low force spring

Abstract: A thermal attachment assembly for heat generating electronic devices which includes a multi-element spring having low force, high deflection, spring fingers, and which is adjustable and attached by screws to a cover to apply pressure directly against electronic components arranged generally perpendicular to at least one edge of a printed wired board (PWB). The attachment assembly includes a heat sink housing in which the electronic components are pressed against an electrically insulating, thermally conductive film positioned against one wall of the heat sink housing. The PWB is snapped to a carrier and both are placed into the housing so that the electronic devices are positioned within spaces of the carrier. The carrier includes sloping surfaces, so that the spring fingers are deflected downward when the cover is attached to the housing, thereby insuring that the spring fingers are properly positioned onto the electronic devices, between the spaces of the carrier.

High-power vertical-cavity surface-emitting lasers

Abstract: Vertical cavity surface emitting lasers have been produced which emit greater than 100 mW CW output power The devices have been optimised for operation at high temperatures, and are heatsunk to improve operation at large bias currents

Electronic component heat sink attachment using a canted coil spring

Abstract: A thermal attachment assembly for heat generating electronic devices which uses a canted coil spring to apply pressure directly against electronic components. The attachment assembly includes a heat sink housing in which the electronic components are pressed against an electrically insulating, thermally conductive film positioned against a surface of a shoulder or side wall of the heat sink housing. The force of the canted coil spring can be counterbalanced by a cover for the housing, or by an abutment that is either fixed in the housing or floats between attachment and an assembly at each of opposite sides of the housing.