Electric lamp and discharge devices: systems – Regulation of the control current and/or potential applied...
Reexamination Certificate
1997-05-29
2001-01-30
Vu, David H. (Department: 2821)
Electric lamp and discharge devices: systems
Regulation of the control current and/or potential applied...
C315S297000, C315SDIG004
Reexamination Certificate
active
06181072
ABSTRACT:
This invention relates to a system for dimming gas discharge lamps such as fluorescent lamps, using electronic ballasts and conventional wiring between the lamp and a conventionally-manipulated dimmer switch. More particularly, the invention relates to circuits in a dimmer switch and in an electronic ballast which can readily provide dimming by their retrofit into existing conventional fluorescent lamp installations, without the need for additional wiring between the dimmer switch and the lamp.
BACKGROUND OF THE INVENTION
The use of dimming apparatus in electric lighting, including gas discharge lamps, is well-known. Examples include two patents to Black, Jr., et al. (U.S. Pat. Nos. 4,947,079 and 4,899,088) which disclose circuits for providing dimming of fluorescent lights by creating “notches” in waveforms supplied by an alternating power source to a conventional inductive ballast. U.S. Pat. No. 4,663,569 to Alley et al. and U.S. Pat. No. 3,935,505 to Spiteri also show fluorescent lamp dimming systems which can be used in a retrofit manner with existing lamp ballasts. U.S. Pat. No. 4,350,935 to Spira and Richardson U.S. Pat. No. 5,194,782 illustrate other approaches to dimming gas discharge lamps.
Other technologies exist to “vary” the output of gas discharge lamps, without providing a full range of conventional dimming functions. Patents such as those to Konopka, et al. (U.S. Pat. Nos. 5,373,218 and 5,194,781) describe control circuits for fluorescent lamps, using a conventional two-position switch and conventional wiring, but only switching between two states—one “high energy” and one “low energy”.
Certain other electronic ballasts (ballasts with built-in circuits) already exist to control the brightness of gas discharge lamp(s). These electronic ballasts are more energy efficient than conventional ballasts, and typically operate by changing the operating frequency of the ballast to maintain a current through the ballasts which is controlled by a reference voltage. Since there is typically an inductor in series with the lamp, increasing the frequency reduces the current to the lamp. The brightness of the lamp is therefore ultimately controlled by varying a reference voltage. Such an approach typically requires additional wiring and/or external circuitry, however, to vary the reference voltage in the ballast and thereby provide the necessary signal. Even for new construction, the costs of installation are increased because, among other things, of the need for the additional set of wires between the switch and the lamp(s). This approach also increases the expense, effort and time required for retrofit situations.
As indicated above, the foregoing and other prior art devices have various shortcomings. Certain of them use too much power, and/or are subject to short-circuiting. Many do not provide dimming over a desirably broad range of light output. Some require additional wiring between the switch and the lamp, thereby making them unsuitable for easy retrofits of existing installations.
OBJECTS AND ADVANTAGES OF THE INVENTION
It is, therefore, an object of the invention to provide an improved apparatus and method that controls dimming of a gas discharge lamp via conventional wiring between a switch and the lamp, using an electronic ballast member.
A further object of the invention is the provision of an apparatus and method of the foregoing character, including corresponding circuitry in a switch member to actuate the dimming function.
Another object of the invention is the provision of circuitry able to adjustably control the brightness of a fluorescent lamp or group of lamps from a single control point, using the wires which supply the power to the lamp(s). Among other things, these power supply wires can be the power wires used in existing, conventional fluorescent or gas discharge lamp installations.
An additional object of the invention is the provision of an electronic ballast system incorporating an internal control reference voltage which is used to set the current through the lamp(s) operated by the ballast. The circuitry of the invention permits the control reference voltage information to be conveyed through the power wires to the electronic ballast and processed there to cause the desired dimming control of the lamp(s).
A still further object of the invention is the provision of a method of retrofitting existing gas discharge lamp installations to provide a full range of dimming, by providing a dimming switch member capable of transmitting a notched signal along the power wire to the lamp, and providing a corresponding electronic ballast capable of demodulating the notched signal to thereafter adjustably control the brightness of the lamp.
Other objects and advantages of the invention will be apparent from the following specification and the drawings.
REFERENCES:
patent: 3935505 (1976-01-01), Spiteri
patent: 4277728 (1981-07-01), Stevens
patent: 4350935 (1982-09-01), Spira et al.
patent: 4482844 (1984-11-01), Schweer et al.
patent: 4604552 (1986-08-01), Alley et al.
patent: 4651060 (1987-03-01), Clark
patent: 4663569 (1987-05-01), Alley et al.
patent: 4701680 (1987-10-01), Alley et al.
patent: 4899088 (1990-02-01), Black, Jr. et al.
patent: 4947079 (1990-08-01), Black, Jr. et al.
patent: 4950963 (1990-08-01), Sievers
patent: 5004972 (1991-04-01), Roth
patent: 5107184 (1992-04-01), Hu et al.
patent: 5138234 (1992-08-01), Miosin
patent: 5144195 (1992-09-01), Konopka et al.
patent: 5191263 (1993-03-01), Konopka
patent: 5194781 (1993-03-01), Konopka
patent: 5194782 (1993-03-01), Richardson et al.
patent: 5248919 (1993-09-01), Hanna et al.
patent: 5293099 (1994-03-01), Bobel
patent: 5373218 (1994-12-01), Konopka et al.
patent: 5500575 (1996-03-01), Ionescu
patent: 5585699 (1996-12-01), Schulz
patent: 5872429 (1999-02-01), Xia et al.
Stacy Kravetz, article entitled “Light Bulb Couldn't Match the Glow of Its Own Press”, May 28, 1997, The Wall Street Journal.
Cha Dean Heesung
Leslie Alexander D.
Yung Allen Wong
EZ Lighting, LLC
J. Mark Holland & Associates
Vu David H.
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