Electric lamp and discharge devices: systems – Plural load device systems
Reexamination Certificate
1999-04-21
2001-09-04
Vu, David (Department: 2821)
Electric lamp and discharge devices: systems
Plural load device systems
C315S291000, C315S309000, C315S315000
Reexamination Certificate
active
06285140
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to variable-effect lighting systems. In particular, the present invention relates to a lighting system having coloured lamps for producing a myriad of colour displays.
BACKGROUND OF THE INVENTION
Variable-effect lighting systems are commonly used for advertising, decoration, and ornamental or festive displays. Such lighting systems frequently include a set of coloured lamps packaged in a common fixture, and a control system which controls the output intensity of each lamp in order to control the colour of light emanating from the fixture.
For instance, Kunins (U.S. Pat. No. 2,515,236) teaches a coloured light source comprising a fixture having a red lamp, a green lamp, and blue lamp, with each lamp being connected to separate output terminal of an autotransformer. The autotransformer is connected to an AC voltage source, and the core of the autotransformer is rotated by a motor so as to vary the voltage applied to each lamp and thereby control the colour of light emanating from the fixture. Although the light source taught by Kunins may be suitable for producing light of varying colour, the use of a motor and autotransformer is bulky and is not suitable for producing intricate colour displays.
More recently, multi-coloured light-emitting diodes (LEDs) have been used with electronic switches to improve the versatility of the lighting system. For instance, Kazar (U.S. Pat. No. 5,008,595) teaches a light display comprising strings of bicoloured LED packages connected in parallel across a common DC voltage source. Each bicoloured LED package comprises a pair of red and green LEDs, connected back-to-back, with the bicoloured LED packages in each string being connected in parallel to the voltage source through an H-bridge circuit. A control circuit, connected to the H-bridge circuits, allows the red and green LEDS to conduct each alternate half cycle, with the conduction angle each half cycle being determined according to a modulating input source coupled to the control circuit. As a result, the bicolour LEDS can be forced to illuminate continuously, or to flash. Further, the colour of light produced by each bicolour LED can be continuously varied between two extremes.
Although the light display taught by Kazar offers an improvement over prior variable-effect lighting systems, the control system and the H-bridge circuitry increases the complexity of the lighting system. Further, the rate of change of coloured light produced is restricted by the modulating input source. Therefore, the range of colour displays which can be produced by the light display is limited.
Phares (U.S. Pat. No. 5,420,482) teaches a controlled lighting system which allows a greater range of colour displays to be realized. The lighting system comprises a control system which transmits illumination data to a number of lighting modules. Each lighting module includes at least two lamps and a control unit connected to the lamps and responsive to the illumination data to individually vary the amount of light emitted from each lamp. However, the illumination data only controls the brightness of each lamp at any given instant. Therefore, the lighting system is not particularly well suited to easily producing intricate colour displays.
Murad (U.S. Pat. No. 4,317.071) teaches a computerized illumination system for producing a continuous variation in output colour. The illumination system comprises a number of different coloured lamps, a low frequency clock, and a control circuit connected to the low frequency clock and to each coloured lamp for varying the intensity of light produced by each lamp. However, the rate of change of lamp intensity is dictated by the frequency of the low frequency clock, and the range of colour displays is limited.
Accordingly, there remains a need for a relatively simple variable-effect lighting system which allows for greater variation in the range of colour displays which can be realized.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a variable-effect lighting system which addresses the deficiencies of the prior art lighting systems.
The variable-effect lighting system, according to the invention, comprises a lamp assembly, and a programmable lamp controller. The lamp assembly includes a first illuminating element for producing a first colour of light, and a second illuminating element for producing a second colour of light. The programmable lamp controller is coupled to the lamp assembly for setting the conduction angle of the illuminating elements according to at least one predetermined pattern stored in a memory of the lamp controller. Preferably, the controller includes a user-operable input to allow the user to select the predetermined pattern and hence the colour display as desired. Alternately, the controller includes a temperature sensor for selecting the predetermined pattern according to ambient temperature, or a clock circuit for selecting the predetermined pattern according to the time.
In one embodiment of the invention, the programable lamp controller comprises a microcontroller for setting the conduction angle according to a plurality of user-selectable predetermined patterns. The lamp assembly comprises a string of series-connected bicoloured light-emitting diodes connected in series between an AC power source and an electronic switch. The electronic switch is coupled to an output of the microcontroller and sets the conduction angle of the illuminating elements of each bicoloured light-emitting diode according to the predetermined pattern selected.
In another embodiment of the invention, the lamp assembly comprises at least one bicoloured light-emitting diode coupled to a DC power source. The first illuminating element of the bicoloured light-emitting diode is coupled to the DC power source through a first electronic switch, and the second illuminating element of the bicoloured light-emitting diode is coupled to the DC power source through a second electronic switch. The electronic switches are each coupled to a respective output of the programmable controller for setting the conduction angles of the illuminating elements.
In yet another embodiment of the invention, the lamp assembly comprises at least one bicoloured light-emitting diode, with each illuminating element of the bicoloured light-emitting diode being driven directly by a respective output of the programmable controller.
Applications of the invention include Christmas tree light strings, temperature-sensitive lights, night lights, jewelry, key chains and decorative lighting displays.
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patent: 2515236 (1950-07-01), Kunins
patent: 3283136 (1966-11-01), Dinkler et al.
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patent: 4317071 (1982-02-01), Murad
patent: 4866580 (1989-09-01), Blackerby
patent: 5008595 (1991-04-01), Kazar
patent: 5384519 (1995-01-01), Gotoh
patent: 5420482 (1995-05-01), Phares
patent: 5619182 (1997-04-01), Robb
patent: 5629587 (1997-05-01), Gray et al.
patent: 5749646 (1998-05-01), Brittell
patent: 5752766 (1998-05-01), Bailey et al.
patent: 5924784 (1999-07-01), Chliwnyj et al.
Gowling Lafleur Henderson LLP
Pharos Innovations Inc.
Tran Thuy Vinh
Vu David
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