Abstract:
An accelerometer design is described. It operates by measuring a change in capacitance when one plate is fixed and one is mobile (free to accelerate). Unlike prior art designs where such changes are caused by variations in the plate separation distance, in the design of the present invention the plate separation distance is fixed, it being the effective plate area that changes with acceleration. A key feature is that the basic unit is a pair of capacitors. The fixed plates in each case are at the same relative height but the mobile plates are offset relative to the fixed plates, one mobile plate somewhat higher than its fixed plate with the other mobile plate being somewhat lower. Then, when the mobile plates move (in the same direction), one capacitor increases in value while the other decreases by the same amount. This differential design renders the device insensitive to sources of systematic error such as temperature changes. A process for manufacturing the design is described.
Abstract:
Design of a micro-mirror switching device and its fabrication in single crystal silicon are described. The device is composed of three main elements: silicon mirror plate with metal-mirror, secondary actuator, and hinge/spring mechanism to integrate the mirror plate with the actuator. p-n junction is first formed on p-type silicon. Trenches are then etched in n-silicon to define the device element boundaries and filled with silicon dioxide. Three layers of sacrificial oxide and two structural poly-silicon layers are deposited and patterned to form device elements. Novel release processes, consisting of backside electrochemical etching in potassium-hydroxide, reactive ion etching to expose oxide-filled trenches from the bottom, and hydrofluoric acid etching of sacrificial oxide layers and oxide in silicon trenches, form the silicon blocks; those that are not attached to structural poly-silicon are sacrificed and those that are attached are left in place to hold together the switching device elements.
Abstract:
It is often desirable to be able to perform an array of micro-chemical reactions simultaneously but with each reaction proceeding at a different temperature and/or for a different time. A classic example is the polymerase chain reaction associated with DNA analysis. In the present invention, this is achieved by means of an apparatus made up of a chip of plastic, or similar low cost material, containing an array of reaction chambers. After all chambers have been filled with reagents, the chip is pressed up against a substrate, typically a printed circuit board, there being a set of temperature balancing blocks between the chip and the substrate. Individually controlled heaters and sensors located between the blocks and the substrate allow each chamber to follow its own individual thermal protocol while being well thermally isolated from all other chambers and the substrate. The latter rests on a large heat sink to avoid temperature drift over time. A process for manufacturing the apparatus is also disclosed.
Abstract:
The invention describes a thermal cycler which permits simultaneous treatment of multiple individual samples in independent thermal protocols, so as to implement large numbers of DNA experiments simultaneously in a short time. The chamber is thermally isolated from its surroundings, heat flow in and out of the unit being limited to one or two specific heat transfer areas. All heating elements are located within these transfer areas and at least one temperature sensor per heating element is positioned close by. Fluid bearing channels that facilitate sending fluid into, and removing fluid from, the chamber are provided. The chambers may be manufactured as integrated arrays to form units in which each cycler chamber has independent temperature and fluid flow control. Two embodiments of the invention are described together with a process for manufacturing them.
Abstract:
A method for forming bonds between similar and dissimilar material surfaces, particularly the surfaces of silicon wafers having various devices disposed thereon, wherein such bonds can be formed at room temperature and do not require the application of high pressures or voltages. The bonding material is polydimethylsiloxane, which is transparent and bio-compatible.