Gte Laboratories Incorporated

Gte Products Corporation

Gte Products Corp. and Gte Laboratories, Inc.

James R McColl

Thomas E Peters

William C Knoll

Da Y Wang

Brian Dale

James O Lawson

A starting circuit is used in combination with a high intensity discharge lamp having electrodes. An inductor is in series with the electrodes of the lamp, and a first switching transistor is arranged in series with a diode and a load resistor. The first switching transistor, diode, and resistor are arranged in shunt with the electrodes of the lamp and in series with the inductor for charging the inductor when the first switching transistor is switched ON. The energy stored in the inductor is discharged as a voltage pulse across the lamp when the first switching transistor is switched OFF. A first bias circuit turns the first switching transistor ON at a first voltage level from an AC power source. A second switching transistor turns the first transistor OFF at a second voltage level. A second bias circuit turns the second switching transistor ON at the second voltage.

Starting circuit for a high intensity discharge lamp

This invention features a method for encoding surface acousting wave (SAW) delay lines. The method uses a split-electrode transducer as a programmable reflector. When shorted out, it does not reflect surface waves. When open-circuited, it partially reflects incident surface waves. As manufactured by conventional photolithographic methods, each of several such transducers is shorted out by a fusible link. In the as-manufactured state, the array of shorted transducers produces no reflection of surface waves. If a fusible link is destroyed by passage of electric current or other means, the corresponding transducer becomes a partial reflector. The status of these switchable reflectors may be read by exciting a separate launch transducer with a burst of electromagnetic energy containing substantial energy at the basis operating frequency of the SAW transducers or at suitable harmonics. SAW energy reflected by the switchable reflectors appears at the same transducer at delay times determined by the spacing of the elements. The presence of a pulse at a given delay time indicates that the corresponding fusible link has been destroyed; conversely, absence of the pulse indicates that the fusible link is intact. Thus, destruction of fusible links provides a method for encoding SAW devices for security and other applications, in situ.

Easily encodable surface acoustic wave (SAW) security devices

The invention features a theft resistant security system for motor vehicles. The system has receptacle with a coupling coil. A SAW (surface acoustical wave) device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle. Problems of crosstalk and wave reflection may produce spurious code pulses in systems of this type. The invention provides techniques for eliminating or reducing these unwanted pulses.

Patterned transducer apparatus for correcting spurious signals in said

An apparatus is featured for controlling remote devices. The status or one or more switches associated with remote devices may be transmitted along a single transmission line. One end of the transmission line contains a surface acoustical wave (SAW) delay line. The SAW delay line responds to an interrogation pulse of radio frequency electromagnetic energy with a series of delayed pulses, each of which transmits the status of a switch by means of the presence or absence of the pulse. The SAW delay line and switches are completely passive, requiring no power source. The transmission line may optionally be interrupted and coupled by means of a pair of inductive coils. This offers the potential for rotation, as within a steering column of an automobile, without wear or damage to the transmission line. The other end of the transmission line contains electronic circuitry to provide the interrogation pulse, to decode the return delayed pulses, and to drive other circuitry as required by the switch positions.

Multiplexed surface acoustical wave apparatus

A theft resistant security system for motor vehicles. The system has a receptacle with a coupling coil. A surface acoustical wave device associated with the receptacle for relative movement thereto is also provided. The SAW device has a code and its own coupling coil for interaction with the receptacle coupling coil. A testing mechanism is connected to the receptacle for determining whether the code of the SAW device is valid for operation of the motor vehicle.

Coded surface acoustical wave (saw) motor vehicle security device

Spurious signal correction for surface acoustic wave (SAW) security

A ZnS:Tm,Ag cathodoluminescent phosphor composition is described. The phosphor emits in the infrared region at approximately 800 nm. The method of making this phosphor is also described. The ingredients are mixed, formed into a cake, dried, comminuted, heated at 800.degree. C. followed by a 1180.degree. C. firing and then cooled to room temperature. All the heating and cooling is done in a hydrogen sulfide atmosphere.

Infrared emitting phosphor

A variable color cathodoluminescent manganese activated zinc silicate phosphor is disclosed. The zinc silicate host is modified by the addition of small amounts of aluminum and phosphorus. Variation in the current density of the cathode ray excitation produces emission varying from green to blue. The method of making the phosphor and a cathode ray tube device employing the phosphor is also disclosed.

Variable color cathodoluminescent composition, method, and display

Manganese-arsenic coactivated zinc silicate phosphors comprising a host of substantially stoichiometric zinc silicate and characterized by enhanced brightness and persistence are prepared by a method which includes a two-step firing schedule. The initial pre-fired phosphor powder blend is formulated with an amount of silicic acid less than or equal to the amount stoichiometrically required for the formation of zinc silicate. Any excess zinc oxide remaining in the mixture following the first firing step is removed by addition of ammonium chloride and a second firing step. The resulting phosphors are substantially free of inert zinc oxide and silica which would otherwise contribute to diminished brightness and persistence.

Method of preparing stoichiometric zinc silicate phosphor with improved

Apparatus for automatically measuring aperture size of a slotted apertured material includes a means for supporting and transporting a slotted apertured material having a plurality of slots with each having a longitudinal axis and a comparator mask overlaying the apertured material and having alternate light transparent and opaque sectors, a light source and a light detector disposed on opposite sides of the slotted apertured material and having a light beam directed therethrough wherein a rhombic-shaped aperture controls the size and shape of the light beam impinging the detector whereby advancement of the rhombic-shaped aperture along a diagonal axis provides a reduced rate of change in light transmitted by the slots and received by the light detector whereby fluctuations in light transmission are reduced for random variations in mask placement.

Automatic aperture size measurement apparatus and process

Luminescent materials comprising solid solutions of lithium zinc fluoride and zinc silicate activated with manganese and, optionally, arsenic having improved brightness, persistence, and crystallinity over prior art P-1 or P-39 phosphors are disclosed. A method of formulating these phosphors, and cathodoluminescent screens employing these phosphors are also disclosed.

Luminescent material, method of making, and screens employing same

A white bodied green-emitting phosphor having improved persistence and brightness comprises manganese activated zinc silicate incorporating arsenic and an alkali metal wherein the arsenic to zinc atom ratio ranges between about 0.00005 to about 0.001 and wherein the alkali metal is present in an amount of between about 0.5 to about 2.0 times the concentration of arsenic present in the phosphor.

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Concord, MA, United States of America

James R McColl