Honeywell International Inc.

Sperry Corporation

Honeywell G.m.b.h.

Alan Stuart Feldman

Brian David Cull

Dennis Michael Davey

Joseph H Ruby

A liquid crystal display (LCD) system having LED backlight luminance sensing is disclosed. An array of LEDs in a backlighting position includes a plurality of LED strings. At least one LED from at least one string is identified as a sampling LED. The light emitted from the sampling LED is detected via an optical path using a light sensor. The reading from the sensor is contrast with a command, which results in a power compensation to the array accordingly. In one embodiment, the system includes a sampling enclosure encasing the sampling LED and light sensor. The sampling LED's direction of emission is altered from the string and reflected from the inside of the enclosure. In another embodiment, the system includes a direct sensing optical path between the light sensor and the sampling LED.

LED backlight luminance sensing for LCDs

A light source incorporatesphosphor-light emitting diodes (LEDs). The LEDs may be raised off the floor of the optical cavity to permit light to be emitted from the base of the LED. Additionally, a reflective protrusion may be placed beneath the raised LED to aid in redirecting light forward. The LEDs may be skewed in relation to adjacent LEDs to reduce interference. Non-white LEDs may be incorporated into the light source to permit for selective color tuning. Fluorescent lamps may also be implemented in combination with the LEDs to form a hybrid light source.The light source may be used as a backlight for a liquid crystal display assembly.

Light source with non-white and phosphor-based white LED devices, and LCD assembly

A lamp includes an enclosure with partitions defining a channel having channel segments and/or providing multiple paths for an electrical arc to travel. The channel segments can be implemented by adding additional electrodes in the channel formed by the partitions, by forming a channel where the arc may travel in multiple directions, or by a combination of these methods. The channel segments and multiple directions of arc travel tend to reduce the voltage required to start the lamp.

Partitioned flat fluorescent lamp

An apparatus and method is disclosed for regulating the cold spot temperature of a light emitting enclosure. A cold spot regulation system defines and controls the temperature of the cold spot. The cold spot regulation system includes an interface housing secured to the light emitting enclosure and two ducts extending from the interface housing. The cold spot regulation system uses a coolant fluid to lower the operating temperature of the light emitting enclosure. The coolant fluid is diverted into one of the ducts. The coolant fluid is passed by the cold spot of the light emitting enclosure and released out the other duct.

Display cold spot temperature regulator

A circuit and method for providing a linear power to a load uses pulse modulation technique where the frequency and pulse width of the pulse width modulated waveform driving the load are varied simultaneously. In one aspect of the disclosure, a pulse width modulator circuit is responsive to a command drive signal for producing the pulse width waveform the width of the pulses varying accordingly. In addition, a frequency control circuit that is also responsive to the command drive signal provides a control current to the pulse width modulator circuit wherein the frequency of the waveform is varied as the pulse widths are varied.

Power linearization technique for controlling the luminance of light emitting display devices

A light source incorporates light emitting diodes (LEDs). The LEDs may be raised off the floor of the optical cavity to permit light to be emitted from the base of the LED. Additionally, a reflective protrusion may be placed beneath the raised LED to aid in redirecting light forward. The LEDs may be skewed in relation to adjacent LEDs to reduce interference. Non-white LEDs may be incorporated into the light source to permit for selective color tuning. Fluorescent lamps may also be implemented in combination with the LEDs to form a hybrid light source.

Methods and apparatus for a light source with a raised LED structure

A control system and method for supplying a constant RMS voltage to a load includes a outer control loop for monitoring a characteristic variable of the system and an inner control loop for maintaining the power delivered to the load as a function of the received input power. A pulse width modulator (PWM) coupled to both control loops delivers pulses representative of an unregulated input voltage duty cycle. The inner control loop compares the duty cycle representation of the input voltage with a duty cycle representation of the pulse and generates a control signal to the PWM accordingly.

PWM power supply with constant RMS output voltage control

A programmable control circuit is disclosed for generating a programmable power curve and ramp. The circuit includes an amplifier having both positive and negative feedback. The positive feedback including a time lag component and the negative feedback including a gain component. The circuit output is easily programmable by varying the component values and/or the input signal. In one embodiment, the rate of change of the control circuit's output waveform may be modified. In another embodiment, the circuit controls the start-up power supplied to a load. In yet another embodiment, the circuit is a waveform generator.

Method and apparatus for programmable power curve and wave generator

An apparatus converts m-bit digital data having a scale factor of K.sub.1 to n-bit digital data having a scale factor of K.sub.2. The apparatus comprises a digital to analog converter which receives the m-bit digital data, for outputting a first analog signal representative of a value associated with the m-bit digital data. An amplifier receives the first analog signal multiplies it by a factor, and outputs a second analog signal. The factor of the amplifier is K.sub.2 /K.sub.1, such that the second analog signal has a value with the scale factor of K.sub.2 associated therewith. An analog to digital converter receives the second analog signal, and converts the second analog signal to the n-bit digital data. The n-bit digital data has the scale factor of K.sub.2 associated therewith, the value representative of the n-bit digital data being essentially equal in the example of the present application to the value representative of the m-bit digital data, however, this is not always a requirement.

Apparatus for conversion of scaled binary data

A driver apparatus for driving one or more electrical loads includes an oscillator for providing an input signal. An amplifier amplifies the input signal. A power transformer has a primary winding for receiving the amplified input signal and at least one secondary winding for providing a drive signal to drive one or more electrical loads. The driver apparatus may include a center tap for the secondary windings or a precision resistive network for providing a pair of diametrically symmetrical drive signals at each secondary winding. A drive signal from one of the secondary windings is compared to a reference signal in an automatic gain control loop for application to the oscillator. An average drive signal could also be derived from one output from each secondary winding to be compared to the reference signal for forming the gain automatic control loop.

Load sensor driver apparatus

An apparatus for converting angular position to a linear voltage. A continuous element dual wiper potentiometer provides triangular waveforms 90.degree. apart to a waveform conversion circuit which generates a linear positive going ramp waveform in response to the angular position of the potentiometer wipers.

Angular position to linear voltage converter

A buffer comparator receives input pulses and produces buffer output signals that drive first and second output comparators arranged to operate as an amplitude-sensitive logic circuit that produces a high level output signal when and only when the internal driving signals have an amplitude between first and second threshold levels. In one embodiment, the output of the buffer comparator is applied directly to the non-inverting input terminal of the first logic circuit comparator and through a low resistance resistor to an R-C network and the inverting terminal of the second logic circuit comparator. The remaining input terminals on the logic comparators are connected to a multiple voltage divider that provides lower and upper threshold voltages to the respective comparators. An input pulse applied to the buffer comparator initiates an internal driving signal that charges the capacitor in the R-C network exponentially. While the voltage on the capacitor rises between the lower and upper threshold levels the logic comparators produce a high level output signal. When the input signal terminates, the low resistance resistor reverses the ordinary switching sequence of the logic comparators and prevents the formation of an output pulse at this time. A second embodiment of the invention dispenses with the means to reverse the ordinary switching sequence during discharge of the capacitor in the R-C network and thus provides a second positive-going output pulse at this time.

Delayed monostable multivibrator

A bi-directional driver system for an electrical load operable in response to two independent logic command signals provides a means for selecting the direction of current flow in the load when driven by the external command. A bridge circuit employs inputs to dual transistor switches operating in the saturated mode in series with the electrical load, cooperating with common emitter transistor linear amplifiers and diodes, and biased by the input logic signal so as to drive the load current in a predetermined direction. The circuit provides protection from undesired power supply current surges when logic command signals are applied to both inputs, and from transients due to failure of a saturated transistor switch at one input to cease conducting before the application of a command signal to the second input. Embodiments for inductive loads and annunciator lamps are described.

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Phoenix, AZ, United States of America

Alan Stuart Feldman