Research International, Inc.

Metricor, Inc.

University of Washington

American Hospital Supply Corporation

Dale M Lawrence

Elric W Saaski

David C Auth

Tim R Majoch

David A McCrae

Eric A Opie

James C Hartl

Roger A Wolthuis

The fluid handling devices are capable of accurately handling substantially continuous fluid flow rates as low as about 0.01 cc/day. The devices are so miniaturized, corrosion-resistant and non-toxic that they are suitable for being implanted in the human body; and are capable of being mass produced at costs so low, by using micromachining techniques, such as etching, that they may be considered to be disposable. The devices are either passive devices which consume no electrical energy at all, or are active devices which consume very small amounts of electrical energy. The devices are reliable because they may have as few as only two parts, only one which is a moving part; and because they may handle fluids at very low pressures. The fluid handling devices include active piezoelectrically driven membrane pumps; and passive fluid flow regulators, on-off valves, flow switches and filters.

Micromachined fluid handling devices

Micromachined filters

The fluid handling devices are capable of accurately handling substantially continuous fluid flow rates as low as about 0.01 cc/day. The devices are so miniaturized, corrosion-resistant and on-toxic that they are suitable for being implanted in the human body; and are capable of being mass produced at costs so low, by using micromachining techniques, such as etching, that they may be considered to be disposable. The devices are either passive devices which consume no electrical energy at all, or are active devices which consume very small amounts of electrical energy. The devices are reliable because they may have as few as only two parts, only one which is a moving part; and because they may handle fluids at very low pressures. The fluid handling devices include active piezoelectrically driven membrane pumps; and passive fluid flow regulators, on-off valves, flow switches and filters.

Methods for manufacturing a flow switch

Method for manufacturing a fluid flow regulator

Micromachined fluid handling apparatus with filter

A method for forming a contoured regulator seat in the substrate of a fluid flow regulator having a membrane with an elastic flexure. The method may involve the steps of deflecting the flexure into the substrate to form the contoured regulator seat while the substrate is in a first, soft condition; continuing that deflection until the substrate is in a second, hard condition; and then ceasing that deflection. The method may include the steps of micromachining a regulator channel into the substrate prior to performing the deflecting step, and then deflecting the flexure into the regulator channel during the deflecting step. The method may also include such steps as installing forming means for restraining a non-regulator seat portion of the substrate during the deflecting step; providing forming relief means for permitting displaced substrate material to exit from the forming means during the deflecting step; and/or providing stencil means for securing the membrane's mounting portion to the substrate during the deflecting step.

Methods for forming a contoured regulator seat

Methods for manufacturing a filter

An oxygen sensor contains an indicator whose change in absorption is a function of the concentration of oxygen in a sample bathing the indicator. Light transmitted and reflected through the indicator of the sensor undergoes an absorption that is characteristic of the concentration of oxygen. The indicator is a viologen whose absorption returns to a steady-state value after it has been subjected to a pulse of short-wavelength light. The rate at which the absorption returns to the steady-state value is a function of the concentration of oxygen bathing the viologen indicator. A measurement system for use with the pO.sub.2 sensor causes a short-wavelength flash to be sent to the sensor and thereafter monitors the time-varying absorption of the sensor to measure the oxygen content of the sample bathing the viologen indicator.

Optical oxygen sensor

An optical pH sensor and a gas sensor utilizing the pH sensor. The pH sensor includes an indicator whose absorbance is a function of the concentration of hydronium ions in a media surrounding the indicator. Light transmitted and reflected through the indicator of the sensor undergoes an absorption that is characteristic of the concentration of the hydrogen ion. The pH sensor can be used as to sense the concenration of a gas in a sample by surrounding the indicator with a liquid or liquid-containing media that changes pH as it is exposed to the gas, and separating the indicator and liquid or liquid-containing media from the gas with a membrane that is permeable to the gas to be measured. A measuring system used with the sensors transmits coherent radiation to the sensor through an optical fiber, separates the radiation returning from the sample into two wavelength bands, and digitally samples the photocurrents produced within the two wavelength bands. A microprocessor performs ratiometric calculations to measure the pH or gas concentration.

Optical pH and gas concentration sensor

A thermo-optical current sensor includes a resistive or semiconducting sensing element that has an optical property that varies as a function of temperature. Current to be measured flows through the sensing element thereby causing heating that is detected by a change in the optical property. The sensing element may be either a resistive or semiconducting material having a temperature dependent optical property or a resistive or semiconducting material that is in thermal contact with an optical temperature sensor. The thermo-optical current sensor may be used as a field meter to measure the intensity of an electromagnetic field or as a current meter to measure the current flowing through a power line.

Thermo-optical current sensor and thermo-optical current sensing systems

A variable gap optical sensor device with a pair of opposed reflective surfaces and having a periodic response function. The sensor includes stiffening means or limiting means intermediate the reflective surfaces to diminish the potential variation in the gap between the reflective surfaces and thereby increase the monotonic range of the periodic response function, resulting in a dual stage sensor response function with a second stage having an increased period.

Optically resonant sensor with increased monotonic range

A thermal cautery system having an endoscopically deliverable probe connected to a power supply and display unit. The power supply and display unit, when triggered by a footswitch, energizes a voltage regulator having a current limited output that supplies power to the probe. The current limiting function of the voltage regulator is disabled for a predetermined period that power is initially applied to said probe to minimize the heating time of said probe. The current through said probe is sensed and used to increase the voltage at the output of the voltage regulator as the current increases to compensate for the voltage drop in the conductors connecting the probe to the power supply. A manually selected portion of the sensed current through the probe is also integrated and used to terminate the flow of current through the probe when the integral of the current with respect to time has reached a predetermined value. A tone generator provides an audible indication when power is being applied to the probe and for a predetermined period thereafter to allow the probe to cool before the absence of the tone signals the removal of the probe from tissue being coagulated. The probe is heated by current flowing through an internal diode having a predetermined breakdown voltage at a predetermined temperature. The temperature of the probe is self-regulated by applying a voltage to the probe that is substantially equal to said predetermined voltage so that the current through the probe is reduced at said predetermined temperature.

Thermal cautery system

A miniaturized, endoscopically deliverable thermal cautery probe for cauterizing internal vessels. The probe is applied to tissues cold, and a large number of electric heating pulses of equal energy are then applied to an internal heating element in the probe. The probe has an internal heating element in direct thermal contact with an active heat-transfer portion that has a low heat capacity to insure quick heating and subsequent cooling, thereby adequately coagulating tissue while minimizing heat penetration and resulting tissue damage. The electrical power applied to the probe is continuously measured and is terminated when the energy delivered reaches a preset value. The number of such pulses applied to the probe (and hence the total energy delivered) may be preset while the duration of the period during which the pulses were applied is displayed. Alternatively, the duration of the period during which such pulses are applied to the probe may be preset while the number of pulses applied (and hence the total energy delivered) is displayed. The heating element for the probe is a controlled breakdown diode which has a breakdown voltage that is a function of its temperature so that the temperature can be controlled. The heating element has a resistance of greater than 0.5 ohm to provide adequate power dissipation with relatively low currents. A washing fluid, preferably flowing along the outside of the probe toward its tip, cleans blood from the tissue to be coagulated to make the source of blood more readily visible.

Fast pulse thermal cautery probe

A multipolar electrosurgical device is described for use in neurosurgery or through the channel of an endoscope or other precision surgery procedures. The device is formed with an insulative probe body, which, in the described embodiment, is sized to pass through a channel of an endoscope to enable the electrocoagulation of blood vessels such as may be needed in the treatment of a gastrointestinal ulcer. The probe body is provided with electrically separate conductors which are formed of a plurality of electrodes distributed over the peripheral surface of the probe body. The electrically separate conductors are so sized in width W and spaced from each other by a distance S as to establish a ratio of W:S which enables effective bipolar treatment of tissue independent of probe body orientation relative to the tissue and without sticking of the probe body to coagulated material. A plurality of at least six electrodes which can form six bipolar electric fields are formed which in one embodiment are aligned longitudinally on the probe body. The electrodes extend onto the probe body's distal end to provide an omnidirectionally effective electrosurgical device. A central conductive wash channel is provided for electrical connection to a set of electrodes at the distal end of the probe body while also providing a passage for fluid to enhance the visibility of the target area for subsequent precise electrocoagulation of the bleeding site. Several embodiments are shown and described.

Growing community of inventors

Lynnwood, WA, United States of America

Dale M Lawrence