Publisher Summary Thermal control of electronic components has one principal objective, to maintain relatively constant component temperature equal to or below the manufacturer's maximum specified service temperature, typically between 85 and 100°C. It is noted that even a single component operating 10°C beyond this temperature can reduce the reliability of certain systems by as much as 50%. Therefore, it is important for the new thermal control schemes to be capable of eliminating hot spots within the electronic devices, removing heat from these devices and dissipating this heat to the surrounding environment. Several strategies have developed over the years for controlling and removing the heat generated in multichip modules, which include advanced air-cooling schemes, direct cooling, and miniature thermosyphons or free-falling liquid films. The chapter summarizes analytical, numerical, and experimental work in literature, in order to facilitate the improvement of existing schemes and provide a basis for the development of new ones. The chapter focuses on investigations performed over the past decade and includes information on the thermal control of semiconductor devices, modules, and total systems.

Thermal Control of Electronic Equipment and Devices

A flat type heat pipe for mounting a heating power element, which is capable of forming an optionally shaped heat transferring path with high accuracy, which is of a thin type and to which fins are easily attached. The flat type heat pipe includes at least two aluminum plates substantially in parallel with each other and brazed to each other so as to form a heat transferring path therebetween. The flat type heat pipe also includes an operating liquid which fills the heat transferring path. Because the heat transferring path 25 is formed by means of press molding, punching, laser beam machining, or cutting various shapes of heat transferring paths can be formed finely and with high accuracy. The flexible flat type heat pipe can be made thin, which allows for a variety of uses. Grooves and wicks can be disposed in the heat transferring path, thereby improving the heat conductivity. Because the surface is flat, the fins can be easily attached thereto, thereby a satisfactory radiation effect can be obtained.

Flat type heat pipe

A cooling device formed in a thermally conductive substrate having at least one microchannel of dimensions that induce capillary action and a surface in thermal contact with a heated region. The microchannel has a longitudinal opening oriented away from the heated region and is supplied with liquid coolant which is contained by a meniscus near the opening. The coolant vaporizes at the meniscus and absorbs heat but, due to increased pressure in the coolant contained by the meniscus, does not boil within the microchannel, allowing more liquid coolant contact with the thermally conductive substrate and walls. The vaporized coolant is discharged into a chamber facing the opening which can be at a lower pressure to remove additional heat by gaseous expansion. The discharge of gaseous coolant allows the capillary flow of the liquid coolant in the microchannels to be unimpeded, and may be augmented by a fluid pump. The gaseous coolant may be in thermal contact with a condenser that liquefies the coolant for supply to the microchannels, by an array of capillaries, in a self contained cooling device. An array of such devices is provided with holes and stacked to connect adjacent liquid and gaseous coolant flows to cool an array of heated objects, such as laser diode bars.

Waste heat removal system

A sealed plate type metallic heat pipe is disclosed having multiple independent through holes which run through the inside of the heat pipe. All of the through holes are connected in fluid communication at each end. A working fluid is disposed in the through holes and a wire or a wire mesh is disposed in at least one of the through holes.

Plate type heat pipe

A structure of a super-thin heat plate comprising surrounding bodies having a thin plate shape and supporting body is disclosed. Each supporting body have function of capillarity and is enclosed within the surrounding bodies. The surrounding bodies and the supporting body are connected by a plurality of welding spots, and the edges are properly sealed. The supporting body is distributed uniformly by a whole web structure. Thus, the heat plate wick structure is very stable with a preferred performance of heat transfer and can be finished easily. In mass production, the structure still has a high stability.

Structure of a super-thin heat plate

PURPOSE:To permit heat transfer between an upper plate and a lower plate of a flat board type heat pipe, by a method wherein operating liquid is permitted to move freely by capillary effect through narrow pipelines between partitioning plates, which are constituted by partitioning the hollow flat board type space between the upper plate and the lower plate by the partitioning plates. CONSTITUTION:A plurality of partitioning plates 3 are provided in a sealed hollow space 2, pinched by both flat plates 1a, 1b of a flat board type heat pipe, orthogonally to the flat plates 1a, 1b with a narrow gap between each others, whereby the sealed hollow space 2 is divided into a multitude of channels 6. The partitioning plates 3 are provided with holes 4, 4a, connecting between the channels 6 while predetermined operating fluid 5 is sealed in the hollow space 2. The channels 6 are formed by predetermined narrow gaps, therefore, the operating fluid 5 may be movable into the direction of the channels 6 by capillary effect. When holes 4a, smaller than the holes 4, are provided on parts covered by the operating fluid 5, the movement of the operating fluid 5 between neighboring channels 6 may be effected.

Flat board type heat pipe

PROBLEM TO BE SOLVED: To support setting of an expandable/contractible optical path length of a measurement cell. SOLUTION: This optical path length setting support device for supporting the setting of the optical path length L of the measurement cell 10, when measuring a sample gas concentration by using the measurement cell 10, capable of setting the optical path length L expandably and contractibly, is equipped with a specific information storage means 22 for storing specific information for specifying the optical path length L suitable for the concentration range of the sample gas in the measurement cell 10, based on sensor outputs from an infrared sensor 15 detected with a plurality of different optical path lengths L in the measurement cell 10; a sensor output fetching means 21a for fetching each sensor output outputted from the infrared sensor 15, corresponding to the plurality of different optical path lengths L, in correlatively with each optical path length L; an optical path length specification means 21b for specifying the optical path length L suitable for the concentration range based on the taken sensor output and the specific information in the specific information storage means 22; and an optical path length change instruction means 21c for instructing change in the measurement cell 10 to the specified optical path lengths L. COPYRIGHT: (C)2006,JPO&NCIPI

Device for supporting optical path length setting, and concentration measuring system

PROBLEM TO BE SOLVED: To provide an electrostatic capacitance-voltage converter capable of preventing continuation of accumulating charge and gaining exact voltage corresponding to the variation of physical quantities and the like as an output. SOLUTION: The connection state of a power source VCC constituted by direct current voltage source generating single polarity voltage to a capacitor series directly connecting to a first and a second variable capacitors C1 and C2, in which one capacity increase leads to decrease of the other capacity by the inversely proportional increment, is switched between a first state for connecting the power source VCC to both ends of the first and the second variable capacitors C1 and C2 by the switching operation of a plurality of switching elements SW1 to SW5, and a second state for separating the power source VCC from the both ends of the first and the second variable capacitors C1 and C2 and connecting the two ends of each variable capacitor C1 and C2.

Electrostatic capacitance-voltage converter

PROBLEM TO BE SOLVED: To provide a gas sample chamber capable of rapidly measuring the concentration of the gas to be measured in an atmosphere and capable of preventing penetrated foreign matter from becoming the measuring obstruction of the concentration of the gas to be measured, and to provide a concentration measuring instrument equipped with the chamber. SOLUTION: The concentration measuring instrument 1 is equipped with the gas sample chamber 2 and microcomputer. The gas sample chamber 2 is equipped with a measuring cell 6, a light source 7 and a light-receiving unit 8. An atmosphere movement permitting part 9, equipped with a plurality of through-holes 10, is provided in the measuring cell 6. The through-holes 10 are provided to the outer wall 6a, positioned at the upper part and the outer wall 6a positioned at the lower part to be opposed to each other in a vertical direction. The light source 7 emits infrared rays of the measuring cell 6, and the light-receiving unit 8 is equipped with a plurality of light-receiving devices 12 and condensing members 13. The light-receiving devices 12 receive the infrared rays from the light source 7 and the condensing members 13 condense infrared rays to the light-receiving devices 12. COPYRIGHT: (C)2009,JPO&INPIT

Gas sample chamber and concentration measuring instrument equipped with the same

PURPOSE:To provide a gas-liquid separator for under-micro gravity use when there remains no bubble in the gas-liquid separating mechanism and time gas- liquid interfaces are made even CONSTITUTION:A gas-liquid separating mechanism 26 where medium liquid 23 and noncondensable gas existing in a vessel 22 are separated from each other and the separated medium liquid 23 and gas are held in a medium liquid holding zone 24 and a gas holding zone 25 installed in the vessel 22, respectively, is provided The gas-liquid separating mechanism 26 makes the medium liquid holding zone 24 communicate with the gas holding zone 25 and simultaneously is equipped with plural capillary passages 28 whose passage cross-sectional area monotonously increases toward the gas holding zone 25 from the medium liquid holding zone 24 and a communicating passage 30 making the ends placed on the medium liquid holding zone 24 side of the capillary passage 28 communicate with each other

Yoshiro Miyazaki

Papers

Flat board type heat pipe

Device for supporting optical path length setting, and concentration measuring system

Electrostatic capacitance-voltage converter

Gas sample chamber and concentration measuring instrument equipped with the same

Gas-liquid separator for under-micro gravity use