Patents by Inventor Michael A. G. Clark
Michael A. G. Clark has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5194133Abstract: A sensor device for the analysis of a sample fluid comprises a substrate in a surface of which an elongate channel is micromachined. The channel contains a material, such as a starch, agarose, alginate, carrageenin or polyacrylic polymer gel, with a biological material for causing separation of the sample fluid as the fluid passes along the channel. The biological material may comprise, for example, a binding protein, an antibody, a lectin, an enzyme, a sequence of enzymes or a lipid. Pairs of sensing electrodes are spaced apart along the walls of the channel. The device may be used, for example, for testing blood samples.Type: GrantFiled: May 3, 1991Date of Patent: March 16, 1993Assignee: The General Electric Company, p.l.c.Inventors: Michael G. Clark, Rosemary A. Lee, Christopher R. Lowe, Philip Maynard, Rajinder S. Sethi, Donald J. Weir
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Patent number: 5157528Abstract: An updatable optical storage device, which may be in microfiche configuration, includes two electrically conductive layers (2,6) between which a layer (5) of a liquid crystal storage material and a layer (3) of a photoconductive material are sandwiched. In order to record an image on the device, the image is projected on to the photoconductive layer through one of the conductive layers, a voltage is applied between the conductive layers, and the storage material is heated at least over regions where the image is to be stored. Projection of the image is continued until the storage material has cooled. The storage material may, for example, be a liquid crystal polymer or a glassy nematic liquid crystal material. The process can be repeated any number of times to update any part or all of the iamge.Type: GrantFiled: June 21, 1989Date of Patent: October 20, 1992Assignee: The General Electric Company, p.l.c.Inventors: Michael G. Clark, Ciaran B. McArdle
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Patent number: 5109287Abstract: Data stored on a remotely-located storage sheet (29,30,31) which may, for example, be a sheet of a spare-parts manual used in the motor trade, can be updated by transmitting a signal from a central station (20) to a receiver (21,22,23) at the remote location. The storage sheet may be in the form of a microfiche. A liquid crystal storage device is used as the storage sheet, which device can be updated by light from a simple laser printer, an imaging array, or a CRT screen at the remote location, operated by the transmitted signal. This avoids the need to replace storage sheets when updating is necessary. The storage sheet may include two electrically conductive layers (2,6) between which are disposed a layer of a liquid crystal storage material (5) and a photoconductive layer (3). The liquid crystal material may be, for example, a liquid crystal polymer or a glassy nematic liquid crystal material.Type: GrantFiled: May 31, 1989Date of Patent: April 28, 1992Assignee: The General Electric Company, p.l.c.Inventor: Michael G. Clark
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Patent number: 5073219Abstract: In a process for mass producing optical storage sheets, an elongate film of a liquid crystalline material is fed lengthwise along a path through an aligning gate. The aligning gate applies to successive areas of the film a field which aligns the molecules. The field may be an electric field and/or a shear field. An aligning layer, such as a surfactant layer may also be used for alignment of the film areas. The aligned film may then be cut into pieces for use as microfiches or microfilms. The film material is preferably a liquid crystal polymer material.Type: GrantFiled: December 11, 1989Date of Patent: December 17, 1991Assignee: The General Electric Company, p.l.c.Inventors: Ciaran B. McArdle, Michael G. Clark, William R. Beck, Carolyn Bowry
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Patent number: 5005952Abstract: A polarization controller comprises at least one stack of nematic liquid crystal cells arranged such that radiation incident on the stack will pass through each cell in the stack in sequence. Synchronized electric or magnetic fields are applied across the cells so as to change the phase retardation of the radiation transmitted through each cell by a chosen amount, the optical axes of the cells being oriented with respect to each other such that the polarization of radiation incident on the controller is caused by the controller to change from a first state to a second state.Type: GrantFiled: December 14, 1988Date of Patent: April 9, 1991Assignee: The General Electric Company, p.l.c.Inventors: Michael G. Clark, Ifor D. W. Samuel
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Patent number: 4996104Abstract: A device for indicating whether a rise in temperature above a predetermined value has occurred includes a support member, such as a label, on which a temperature-sensitive material is deposited. The material includes a large number of fracturable microcapsules containing a medium which changes from a solid state to a liquid state at the predetermined temperature value. The viscosity of the medium in its liquid state and the material of the support member are chosen such that the distance d.sub.1 by which the medium flows across the support member after the fracturing of the microcapsules so as to activate the device is indicative of the time between activation of the device and cooling of the device to below the predetermined temperature value. If the temperature is subsequently allowed to rise above the predetermined value, the medium will again assume its liquid state and will flow further across the support member, reaching a distance of, say, d.sub.Type: GrantFiled: March 23, 1989Date of Patent: February 26, 1991Assignee: The General Electric Company, p.l.c.Inventors: Beatrice M. Nicholas, Alan Mosley, Cyril Hilsum, Michael G. Clark
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Patent number: 4935631Abstract: A radiation meter for measuring the intensity of incident ultraviolet radiation in a predetermined wavelength band against a background of broadband radiation, such as sunlight, includes a sheet of a material incorporating a fluorescent dye. The dye is selected to absorb radiation in the predetermined wavelength band and consequently to emit fluorescent radiation. The fluorescent radiation is internally reflected within the sheet and emerges from an edge of the sheet, where it impinges on a photodiode. The photodiode produces an output which is dependent upon the intensity of the ultraviolet radiation. This output is used to drive a suitable display. The unwanted background radiation passes through the sheet without causing fluorescence of the dye, and is absorbed in an absorbent backing layer. The photodiode is so positioned and screened that the background radiation cannot impinge upon it.Type: GrantFiled: September 26, 1988Date of Patent: June 19, 1990Assignee: The General Electric Company, p.l.c.Inventors: Alan Mosley, Brian L. Kingston, Michael G. Clark, Martin R. Lewis
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Patent number: 4909626Abstract: An optical component comprises a thin film of an electrically controllable birefringent material confined between substantially planar surfaces. A respective electrode structure is provided on each of the surfaces, each electrode structure being patterned such that an electric field applied across the film by means of electrode structures, when a voltage is applied therebetween, causes modulation of the refractive index of the material such that the wavefront of electromagnetic radiation incident of the component and transmitted through the thin film is divided into Fresnel zones.Type: GrantFiled: April 27, 1989Date of Patent: March 20, 1990Assignee: The General Electric Company, p.l.c.Inventors: Alan Purvis, Michael G. Clark
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Patent number: 4861992Abstract: A method of testing thermal imagers includes heating selected portions of a quantity of a smectic liquid crystal material (9) with a laser (25) such that the material in the selected portions changes from a homeotropic texture in which it is transparent to incident infrared radiation to a focal conic texture in which it scatters incident infrared radiation. An infrared source (27) is arranged to direct infrared radiation onto the quantity (9) so as to read the pattern of selected portions across the quantity.Type: GrantFiled: November 12, 1987Date of Patent: August 29, 1989Assignee: The General Electric Company, p.l.c.Inventors: Michael G. Clark, Michael C. Wiltshire
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Patent number: 4834505Abstract: An electro-optic display comprises a two dimensional array of liquid crystal cells (C11A,B to C44A,B) each switchable by means of electrical signals applied to respective pairs of address lines connected to the cell by respective transistors (T11-T44). Each main electrode of each transistor is isolated from the rest of the array by a respective cell of the array.Type: GrantFiled: October 16, 1987Date of Patent: May 30, 1989Assignee: The General Electric Company, p.l.c.Inventors: Piero Migliorato, Michael G. Clark
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Patent number: 4832462Abstract: A liquid crystal device comprises a ferroelectric smectic phase liquid crystal enclosed between two surfaces, the surfaces being such that the directors of the liquid crystal adjacent the surfaces are not parallel to the surfaces. The directors adjacent one of the surfaces are not parallel to the directors adjacent the other surface, the liquid crystal cone angle being equal to half the angle between a pair of directors each adjacent a different one of the surfaces.Type: GrantFiled: June 12, 1987Date of Patent: May 23, 1989Assignee: The General Electric Company, p.l.c.Inventors: Michael G. Clark, Alan Mosley, Carolyn Bowry, Beatrice M. Nicholas
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Patent number: 4568937Abstract: An induction loop vehicle detector comprises an oscillator circuit having a plurality of capacitors switchable in circuit with a road loop under the control of a microcomputer to determine the oscillator frequency. The microcomputer monitors the oscillator frequency and controls the switching of the capacitors to periodically return the frequency to a predetermined value. A counter counts a predetermined number of oscillator cycles and gates of h.f. clock into a second counter whereby the count of the counter represents the oscillator period. A "vehicle detected" output is given when the monitored frequency alters by more than a predetermined amount, representing a decrease in the inductance of the loop. On detecting an increase in the inductance above a predetermined threshold the detector is inhibited for a predetermined time, e.g. about 1 second, to avoid errors caused by magnetic effects.Type: GrantFiled: June 2, 1983Date of Patent: February 4, 1986Assignee: Microsense Systems, LimitedInventor: Michael A. G. Clark
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Patent number: 4547773Abstract: A multi-character multi-segment electrically addressable display panel. Character segments are defined at each of a number of adjacent locations by the overlap of two sets of electrodes. The electrodes of one set are each associated with a location and a group of one or more segments. The electrodes of the other set extend across each location and are associated with no more than one segment in each segment group. The panel is addressed using isogonal signals, e.g. pseudo-random binary sequence coded signals. The panel medium may be of dyed or undyed cholesteric-to-nematic phase change effect liquid crystal material, of low threshold or wide temperature range liquid crystal material.Type: GrantFiled: January 19, 1983Date of Patent: October 15, 1985Assignee: National Research Development CorporationInventor: Michael G. Clark
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Patent number: 4527863Abstract: A polar co-ordinate display of full 360.degree. arc comprised of electrode bearing substrates each side of a layer of dyed phase change liquid crystal material. One set of electrodes comprises concentric spirals, the other set comprises radials. The display is multiplex addressed using four select waveform signals. These four signals V.sub.1, V.sub.2, V.sub.3, and V.sub.x satisfy the following conditions:RMS(V.sub.x -V.sub.i)=V.sub.p, i=1, 2 or 3;RMS(V.sub.1 -V.sub.2)=V.sub.p ; RMS(V.sub.1 -V.sub.3)=V.sub.0where V.sub.p is an upper threshold voltage, and V.sub.0 a saturation voltage for dyed phase change hysteresis, and may be of the coded form;V.sub.1 =,1010,;V.sub.2 =,1100,;V.sub.3 =,0101,;V.sub.x =,0110,.These may be generated using two 2-bit registers with exclusive OR-gate feedback.Type: GrantFiled: October 12, 1983Date of Patent: July 9, 1985Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern IrelandInventors: John L. Glasper, Ian A. Shanks, Michael G. Clark
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Patent number: 4491841Abstract: A vehicle detector has an inductive sensing loop that is a frequency determining element of an oscillator. A first counter is operated to sample the oscillator frequency or period and the count achieved is applied as a preset reference to a second down counter which is counted down in one sample period while a fresh count value is being established in the first counter. The residue in the second counter at the end of a sample period is examined by detection logic to determine the presence of a vehicle. Preferably the first counter is updated every Nth sample period whereas the second counter is activated every sample period. Upon vehicle detection the first counter is frozen at the value preceding detection, the second counter continuing operation.Type: GrantFiled: September 14, 1983Date of Patent: January 1, 1985Assignee: Sarasota Automation LimitedInventor: Michael A. G. Clark
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Patent number: 4459561Abstract: A vehicle detector installation includes a loop oscillator the loop of which is laid in the roadway and which is locked in operation to a voltage controlled oscillator (VCO). Vehicle detection is effected by a phase detector monitoring the phase difference between the oscillators. The VCO is incorporated in a phase-lock loop (PLL) that is capable of locking to a multiple of a reference frequency oscillator over a range of multiples. To achieve the locking of the loop oscillator to the VCO, means are provided for disabling the normal operation of the PLL and sweeping the VCO over its range of frequency until the phase detector indicates that the loop oscillator and VCO frequencies are equal. This indication activates the PLL to its normal operation to pull the VCO and therewith the loop oscillator to an adjacent multiple of the reference frequency. The PLL is maintained by a repeated charge/discharge cycle of the VCO capacitor that is dependent on the phase of the reference oscillator and the VCO.Type: GrantFiled: October 19, 1981Date of Patent: July 10, 1984Assignee: Sarasota Automation LimitedInventors: Michael A. G. Clark, Robert C. Bromwich
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Patent number: 4358749Abstract: In a vehicle detector installation employing an inductive sensing loop that is a frequency determining element of an oscillator, the oscillator is provided with a voltage controlled capacitor as another frequency determining element and is made the voltage controlled oscillator (VCO) of a phase locked loop whereby the VCO is locked to a reference frequency. The presence of a vehicle in the vicinity of the loop causes the capacitor voltage to vary to maintain lock. The varying voltage is applied to an auxiliary VCO whose frequency is accordingly varied and may be analyzed for vehicle detection purposes. The oscillator containing the sensing loop is thereby prevented from influencing nearby installations by the FM sidebands that would be produced in the absence of the frequency locking. A group of such installations may use a common reference frequency source with each installation operating at its own locked frequency by virtue of means providing a programmable frequency division ratio from the source.Type: GrantFiled: October 31, 1980Date of Patent: November 9, 1982Assignee: Redland Automation LimitedInventor: Michael A. G. Clark
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Patent number: 4328493Abstract: A liquid crystal color display comprises a cathode ray tube which emits at two or more wavelengths, a liquid crystal cell, a neutral analyzer and two color selective polarizers. The cell is switched in synchronism with different images supplied to the cathode ray tube so that the different images are observed in the different colors simultaneously. The cell is respectively switched ON and OFF by application of signals at a low frequency f.sub.1 and a high frequency f.sub.h. To avoid a patch appearance due to different parts of the liquid crystal having different twists a gap is allowed between switching the signals f.sub.1 and f.sub.h so that the total shear of the liquid crystal may be kept below a critical shear value.Type: GrantFiled: January 23, 1980Date of Patent: May 4, 1982Assignee: National Research Development CorporationInventors: Ian A. Shanks, Michael G. Clark, Frank M. Leslie
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Patent number: 4253071Abstract: A problem with phase modulators particularly when modulating high frequency signals with signals of audio frequency is that noise is generated during the production of a free running ramp signal and noise is present on the modulating signal so that accurate detection of the modulating signal is not possible. In order to avoid this problem a fast ramp signal is generated by charging a low value capacitor (12) from a constant current source (13) in response to the edge of an applied timing signal. The starting voltage of the ramp signal is related to the phase of a modulating signal derived from a source having a low output impedance (25). The ramp signal is applied to a level detector (16) having a defined switching level, which detector produces an output edge signal in response to the ramp signal traversing the switching level in a given direction.Type: GrantFiled: April 25, 1979Date of Patent: February 24, 1981Assignee: U.S. Philips CorporationInventors: Michael J. Underhill, Michael A. G. Clark
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Patent number: 4184122Abstract: Phase comparison apparatus, for example for use in phase lock loop (PLL) systems, comprises a first and a second phase comparator. The first comparator has a high gain (e.g. 1000) and a narrow phase difference range (e.g. 5.degree.) and the second phase comparator has a substantially greater range (e.g. 720.degree.). The second phase comparator is automatically switched out when the apparatus is operating in the narrow range and the outputs of the two comparators are proportionately combined in such a way that the combined output characteristic is linear over the whole range covered by the apparatus. The lock-up time of a PLL system using the apparatus is reduced by 10 to 100 times and system noise due to the apparatus can be reduced to negligible proportions.Type: GrantFiled: January 12, 1978Date of Patent: January 15, 1980Assignee: U.S. Philips CorporationInventors: Michael A. G. Clark, Michael J. Underhill