Honeywell International Inc.

Honeywell G.m.b.h.

Bruce Anthony Pitman

Scot Olson

Richard Mitchel Meldrum

A driver circuit provides a drive current from a power source to an arc lamp to produce a light. The circuit includes a transformer having primary and secondary windings, with the ends of the secondary winding providing the lamp drive current to the arc lamp. A current steering module provides a drive output from the power source to the transformer in response to a current steering input, and a current control loop adjusts the current steering input in response to the current in one of the windings of the transformer. A luminance control loop adjusts the current steering input in response to the brightness of the light and a luminance command. A power control module may be further provided to generate a boost command in response to a difference between the brightness of the arc lamp and a luminance command.

System and methods for dimming a high pressure arc lamp

An assembly for heating a fluorescent lamp (such as the lamp used in a flat panel display) includes a circuit card having a plurality of transistors each configured to produce heat disposed thereon. A thermally-conductive layer is disposed proximate to the plurality of transistors, and the fluorescent lamp is disposed proximate the thermally-conductive layer such that the heat from the transistors is transmitted to the fluorescent lamp via the thermally-conductive layer. By controlling the heat applied to the fluorescent lamp, microclimates in the lamp can be reduced or eliminated, thereby improving the performance of the lamp.

Methods and apparatus for thermal management of fluorescent lamps

A lamp driver system is provided that facilitates improved efficiency and brightness control for an optical display system. The lamp driver system provides this improved efficiency and brightness control through the precise control of the plasma in the lamp. The lamp driver system excites the electrons in the plasma such that their obtained velocity is optimized to increase the probability of collision with the mercury atoms in the lamp. Collisions with mercury atoms release ultra-violet photons, which in turn excites the phosphor coating in the lamp. The resulting relaxation of the phosphor atoms releases photons in the visible spectrum, thus providing light with the required frequency components to illuminate the display.

Fluorescent lamp driver system

Methods and apparatus for controlling the brightness level of a lamp in a backlit LCD display include primary and secondary controllers. The primary controller establishes the arc drive to the lamp to achieve the desired lamp brightness. The primary controller includes a desired brightness set-point as a first input, and a feedback signal corresponding to actual brightness detected at the lamp as a second input. The primary controller operates in real time, essentially adjusting the lamp arc drive instantaneously as a function of the detected brightness feedback signal. The secondary controller is employed to fine tune the control of the lamp by determining whether the desired brightness level may be achieved more efficiently. The secondary controller varies one or more parameters, such as temperature, within the lamp to achieve the optimum operating point of the lamp at the desired brightness level.

Methods and apparatus for controlling the intensity and/or efficiency of a fluorescent lamp

Disclosed is a control mechanism for regulating the temperature of a fluorescent lamp tube located within a housing. The control mechanism includes a cold spot mechanism defining the cold spot of the lamp tube, a heating mechanism, a power supply and a temperature sensor. The heating mechanism is connected to the power supply and is contiguous with a portion of the cold spot mechanism located outside of the housing. The temperature sensor is also coupled to the power supply and monitors the temperature of the cold spot mechanism. Based upon the temperature of the cold spot mechanism, the temperature sensor operates the power supply, so as to deliver power to the heating mechanism to warm the cold spot mechanism and maintain a cold spot temperature that allows the lamp tube to generate maximum visible light output.

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Phoenix, AZ, United States of America

Bruce Anthony Pitman