Abstract: A ratiometric method for using optical sensors is provided to measure dissolved oxygen in a fluid sample. The sensor is formulated so as to contain an oxygen permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, an oxygen-sensitive indicator component and a reference dye component. The emission spectrum from the indicator component is calibrated by comparison with that of the reference dye, which is substantially less sensitive to oxygen-quenching and which has a photodecomposition rate similar to the indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: A protection mechanism for a microprocessor has multiple privilege levels for tasks running on the microprocessor. A memory control unit for the microprocessor includes segment registers that identify segments of memory assigned to various tasks. When a segment register is loaded with the address of a new segment for a task, the protection mechanism within the memory control unit compares the privilege level of the task requesting the segment with the privilege level of the requested memory segment and determines whether the requested memory segment can be assigned to the requesting task. The relationship between the privilege levels is programmable to provide flexibility in generating privilege faults.

Abstract: A segment limit check circuit performs limit checks on fetch addresses generated by a CPU. The circuit and method for performing the fetch limit check are simplified over the prior art by effectively moving the fetch limit check to linear address space. For a microprocessor that uses physical addresses of 32-bits and performs fetches as 16-byte aligned accesses, the circuit of the present invention generates a 33-bit linear address and a 33-bit upper limit value. A comparator compares the upper 29 bits of the linear address with the upper 29-bits of the upper limit value. If a match occurs, the circuit decodes the 4 low-order bits of the upper limit value to determine which of the 16 instruction bytes (if any) fall outside the segment limit.

Abstract: A microprocessor circuit monitors addresses generated by the microprocessor to check for various address-exception conditions. Fetch-exception status bits are generated for each instruction byte to indicate whether an address-exception was detected for each respective byte address. Once fetches are performed, the fetch-exception status bits are fed to an instruction buffer with the corresponding instruction bytes, where they are maintained until execution. Decode logic of an instruction control unit analyzes the fetch-exception status bits upon execution, and generates exceptions before the corresponding exception-causing instructions are executed. Address-exceptions occurring as the result of operand accesses are handled immediately. The operand access causing the exception is aborted, and the decode of the following instruction is modified to generate a micro-interrupt. A micro-interrupt routine determines the cause of the interrupt, and generates the appropriate exception.

Abstract: An access control unit for a microprocessor receives fetch requests and operand access requests from a CPU of the microprocessor, and issues the requests to a bus/cache unit in a manner which reduces interference between fetch requests and operand access requests. Fetch addresses for fetch requests that cannot be immediately performed by the bus/cache unit are placed in a fetch address queue, allowing such fetch requests to be postponed. Operand access requests received by the access control unit are performed prior to postponed fetch requests. Thus, the execution unit of the CPU can continue to execute instructions which require operand accesses without waiting for pending fetch requests to be performed. Fetch requests that have been postponed by the access control unit are attempted on every clock cycle for which no operand access request is pending.

Abstract: A ratiometric method for using optical sensors is provided to measure dissolved oxygen in a fluid sample. The sensor is formulated so as to contain an oxygen permeable membrane of a cured perfluorinated urethane polymer and, incorporated therein, an oxygen-sensitive indicator component and a reference dye component. The emission spectrum from the indicator component is calibrated by comparison with that of the reference dye, which is substantially less sensitive to oxygen-quenching and which has a photodecomposition rate similar to the indicator component. Methods for making and using the membrane and sensor are provided as well.

Abstract: A circuit and method suspend the operation of a CPU of a microprocessor while a memory control unit (MCU) of the microprocessor performs certain operations for the CPU. The circuit is used to generate two internal clock signals from an external clock signal generated off-chip. The first internal clock signal is used to control the MCU and runs continuously. The second internal clock signal is used to control the CPU. During MCU operations requiring wait states, a stall circuit stalls the second internal clock to suspend the operation of the CPU and to thereby prevent CPU register values from changing. The circuit and method eliminate the need for certain data circulation logic within the CPU.

Abstract: An AC TFEL device includes a front electrode set deposited on a transparent substrate and a rear electrode set, the electrode sets enclosing a thin film laminate which includes a pair of insulating layers sandwiching an alkaline earth thiogallate thin film phosphor doped with a rare earth activator. The thiogallate phosphor layer is capable of producing blue light of sufficient intensity to create a full color TFEL panel.

Abstract: A method for annealing a deposited material on a substrate structure, where the annealing temperature of the deposited material is greater than the melting temperature of the substrate structure, including the step of inserting the substrate structure into an oven preheated to a temperature above the annealing temperature. The substrate structure is kept in the oven for a time interval wherein the mean temperature of the deposited material is above the annealing temperature and the mean temperature of the substrate structure is below its melting temperature. The substrate structure may be actively cooled while in the oven, thus increasing the time interval the mean temperature of the deposited material can be maintained above the annealing temperature.

Abstract: A chemical sensor matrix is provided for use in medical, biological and industrial applications. The gas sensor includes a cross-linked fluoropolymer matrix of a composite having a gas-sensitive indicator within the matrix. The composite includes a highly fluorinated monofunctional acrylate monomer and a multifunctional acrylate cross-linking agent. Gas-sensitive indicator components which are suitable for detecting gases such as oxygen, carbon dioxide and the like represent indicators suitable for incorporation into the cross-linked fluoropolymer matrix.

Abstract: Fiber optic chemical sensors and materials suitable for use in making same are provided. A charged hydrogel matrix membrane is suitable for affixing to the distal end portion and the like of an optical fiber waveguide, which charged hydrogel matrix has dispersed therewithin an oppositely charged ion exchange resin powder, which ion exchange powder has a colorimetric indicator component electrostatically coupled thereto, which colorimetric indicator component has the same charge as the charged hydrogel.

Abstract: A fluorescence energy transfer indicator, a chemical sensor incorporating it, and a method for making it are provided, such being useful in medical, biological and industrial applications. The fluorescence energy transfer indicator includes a rigid spacer group that tethers together a fluorescent energy donor and a colorimetric indicator acceptor, the tethering being across a predetermined, known or determinable length in order to thereby tailor the indicator to the specific needs of the chemical sensor. The emission spectrum of the fluorescent energy donor overlaps with an absorbance spectrum of the colorimetric indicator acceptor, which undergoes a change in color or in color intensity as a function of the species being monitored or measured in accordance with parameters of the species such as pH, oxygen concentration, carbon dioxide concentration and the like.

Abstract: A display having a filter disposed on, or in, a portion of the substrate is described. The filter is generally a red filter such that light passing through the filter will produce a red colored light. The filter is comprised of cadmium sulfoselenide in a 62/38 composition (CdS.sub..62 Se.38). The light is generated by a phosphor element which will emit a compatible color light. Other light emitting phosphors, such as green and blue, are also utilized without a filter to provide a multi-colored display.

Abstract: An optical probe is presented for use in measuring pH and oxygen content in blood in a blood vessel within a living body. An elongated flexible optical fiber means is provided which has a proximal end and a distal end. The distal end is adapted to be inserted into a blood vessel. A membrane is secured to the distal end of the optical fiber and receives light from the distal end of the fiber and returns light therethrough to the proximal end. The membrane is constructed of hydrophilic porous material containing a pH sensitive dye. A plurality of microspheres are embedded in and carried by the membrane. These microspheres are constructed hydrophobic material and each carries a fluorescent dye quenchable with oxygen. Consequently, when light is supplied to the proximal end of the optical fiber, it is conveyed to the membrane. This causes the pH sensitive dye to react and light is conveyed through the optical fiber having an intensity level indicative of the pH level in the blood.

Abstract: An electroluminescent device includes a tin oxide electrode having a textured surface with a phosphor layer interposed between dielectric layers overlying the textured surface. The textured surface propagates through the overlying layers so as to reduce the amount of generated light trapped in the device structure and increase the output brightness of the device.

Abstract: An electroluminescent film of an activated alkaline earth metal sulfide phosphor is produced by a method utilizing low temperatures for substrate protection and achieving excellent crystallinity and enhanced brightness. A layer of an alkaline earth metal halide and a suitable activatior is deposited on the substrate, heated to melt the halide and treated with gaseous hydrogen sulfide to form the phosphor. A precursor for the halide may be deposited on the substrate heated to melting temperature and treated with gaseous hydrogen halide to form the halide in-situ.

Abstract: The optical blood pressure catheter includes an elongated optical fiber located within the lumen of the catheter for transmitting light received at its proximal end to its distal end where the light is reflected from a mirror and the reflected light is received at the distal end and transmitted back to the proximal end thereof. A pressure transducer is located at the distal end of the catheter and includes a mirror which is spaced forwardly of the distal end of the optical fiber and is fixed in position relative thereto so as to receive and reflect light emitted from the distal end of the optical fiber and back into the distal end thereof. A side port is provided in the catheter housing adjacent its distal end and the side port is sealed with a pressure-responsive membrane responsive to pressure acting transversely thereof.

Abstract: A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

Abstract: A photodetector including a light transmissive electrically conducting layer having a textured surface with a semiconductor body thereon. This layer traps incident light thereby enhancing the absorption of light by the semiconductor body. A photodetector comprising a textured light transmissive electrically conducting layer of SnO.sub.2 and a body of hydrogenated amorphous silicon has a conversion efficiency about fifty percent greater than that of comparative cells. The invention also includes a method of fabricating the photodetector of the invention.

Abstract: A lenticular array suitable for CCD stripe filters is made by anisotropically etching a V-shaped groove in a 100 silicon wafer wherein the walls of the V-grooves are made by intersecting 111 planes, replicating the V-grooves in metal to form an inverted V-master and spin coating a hardenable resin thereon to form a uniform array of lenses between the peaks.