Two bodies such as an integrated circuit and a heat sink are maintained in a low stress and high thermal conductance abutment by pressure from capillary attraction. A surface of one of the bodies is provided with grooves preferably having reentrant surfaces. A surface of the other body is brought into abutment with the grooved surface with a liquid therebetween which partially fills the grooves. The grooves act as reservoirs for excess liquid so that a minimum thickness liquid interface is achieved, and the grooves enable trapped gas to escape out the open ends thereby preventing voids between the two bodies. Importantly, the groove geometry enforces a well-defined attractive force between the two surfaces due to the liquid surface tension.

Heat sink and method of attaching heat sink to a semiconductor integrated circuit and the like

An integrated circuit is mounted on, and electrically connected to an underlying substrate by the flip-chip technique. In this technique, the chip is inverted and bonding pads on the chip are soldered to correspondingly located bonding pads on the substrate. By the invention a continuous ribbon or loop of solder or polymer extends between the chip and substrate surfaces and defines a sealed cavity. Because the interior of the cavity is sealed from contaminants, conducting leads of the chip or substrate can be left uncovered within the cavity so reducing the capacitance of high frequency circuits. The substrate can be a connection medium such as a printed circuit board or could be another integrated circuit chip.

Integrated circuit chip package

An electrodeless discharge lamp has an ionizable medium comprising a particular gas composition at a particular pressure within a sealed envelope. Radio frequency electrical power is applied to an induction coil, the magnetic induction field of which is coupled to the medium. For a particular radio frequency, the magnitude of the induction field is selected to maximize the light emitted by the discharge per watt of radio frequency power coupled thereto. The radio frequency is preferably between 3 megahertz and 300 megahertz. In one embodiment, a mixture of mercury vapor and argon is contained within an envelope having an open cylindrical cavity into which the coil fits; the portion of the interior surface of the envelope defining the cavity has a layer of an electrically insulative, ultraviolet reflective material, and the entire interior surface of the envelope has a phosphor layer; radio frequency power at a frequency of about 4 megahertz is applied to the coil by an oscillator having a tuned circuit including the inductor and the discharge.

Light generation by an electrodeless fluorescent lamp

Solid state memory devices employed in crash survivable flight data recorders must be thermally insulated to prevent loss of stored data if the aircraft burns. To provide adequate thermal isolation at minimal size, the solid state electronic memory devices (26) are encapsulated in a synthetic organic wax or pentaerythritol (28) that exhibits a phase transition at a temperature: (a) above the normal operating temperature of the memory unit (10); and below the maximum acceptable peak temperature for the memory devices (26). The synthetic organic wax of pentaerythritol (28) is surrounded by a thermal liner (18) constructed of solid thermal insulating material. A metal enclosure (12) houses and protects the thermal liner (18), the synthetic organic was or pentaerythritol (28) and the memory devices (26).

Heat shielded memory unit for an aircraft flight data recorder

A flow sensor for determining the velocity and direction of a fluid flow including a substrate, a heat source located on the substrate, and a first and a second heat sensor located on the substrate to detect at least a portion of heat generated by the heat source. The first and second heat sensors and the heat source are arranged in a non-linear orientation.

Fluid flow sensor

An improved fluid flow sensor configuration comprises a thin membrane of a low thermally conductive material having one surface in thermal contact with the heating and temperature sensitive elements of a fluid flow sensor and the other surface in thermal contact with a fluid whose flow rate is measured by the fluid flow sensor.

Improved fluid flow sensor configuration

An integrated power transistor has at least one emitter region, having a ballasting resistance to reduce the possibility of second breakdown. Also integrated within the device is a voltage control diode, located between the collector terminal and the emitter terminal, to protect against high voltages caused by transient surges, particularly during switching times.

Integrated power transistor with ballasting resistance and breakdown protection

An improvement for a transcalent semiconductor device includes a semiconductor ballast resistor in contact with the emitter regions of a semiconductor transistor. The semiconductor transistor with the ballast resistor in contact therewith is sandwiched between two closed heat pipes wherein one heat pipe is in thermal and electrical contact with the transistor and the other heat pipe is in thermal and electrical contact with the resistor.

Semiconductor device with ballast resistor adapted for a transcalent device

An amplifying circuit comprises a differential amplifier receiving input signals and having first and second output connections to which the input and output connections of a current amplifier respectively connect. A transistor receives signals at its gate from the second output connection of the differential amplifier and has a capacitor connected between its input and output electrodes. A feed-forward circuit, responsive to signals at the first output connection of the differential amplifier, develops a feed-forward signal which is applied to the output electrode of the transistor and poled so as to reinforce the signals thereat. The feed-forward signals tend to cancel signals conducted through the capacitor at high frequencies where the transistor exhibits reduced gain.

John A. Olmstead

Papers

Improved fluid flow sensor configuration

Integrated power transistor with ballasting resistance and breakdown protection

Semiconductor device with ballast resistor adapted for a transcalent device

Operational amplifier with feed-forward compensation circuit

Remote cutoff junction gate field effect transistor