This application claims the benefit of the following foreign applications: Chinese Applications No. 200520013482.0, filed Jul. 20, 2005; No. 200520013483.5, filed Jul. 20, 2005; No. 200520013484.X, filed Jul. 20, 2005; No. 200520116564.8, filed Nov. 21, 2005; and No. 200520116919.3, filed Dec. 1, 2005.
1. Field of the Invention
The present invention relates generally to a fluorescent lamp and more particularly, to a fluorescent lamp for lighting.
2. Description of the Prior Art
The existing high power tubular fluorescent lamps (FL), e.g., T12, T10, T8, T5 and T4 FL etc. are the hot cathode FL. It has been used for lighting beginning around 1940, and is widely used in the world now. It has the advantages of high efficiency, low cost and able to generate different color light. However, it has a short operating lifetime, and very short ON/OFF switching lifetime. It is also, difficult to control and change the color of light emitted by the hot cathode FL or to change its color temperature.
The cold cathode fluorescent lamp (“CCFL”) has long operating lifetime, very long ON/OFF switching lifetime and high efficiency. It is widely used for LCD backlight, and some claims that the lifetime of CCFLs can be up to 60,000 hours. Cold cathode fluorescent lamp, or CCFL has been used to provide backlight for LCD display for some time. There are basically two types of CCFL backlight: (1) Edge type CCFL backlight; (2) Front type CCFL backlight; The Edge type has been the mainstream design for smaller size LCD backlights, while the Front type has emerged to be the mainstream design for the larger size LCD TV Displays.
There are three kinds of Front type CCFL backlight. A first type uses a tubular, U shape or serpentine shape CCFL in a housing, such as shown in U.S. Pat. No. 6,793,370 and US Patent Pub. 2006/0023470. A second type uses a flat container containing electrodes and discharge gas to provide a flat light source. A third type uses dividers between two plates to create a serpentine shaped passage with electrodes at the two ends of the passage between the two plates in a vacuum environment to create a flat lighting source, such as shown in U.S. Pat. No. 6,765,633. All these three types of devices are used as LCD backlight. There are no controller or suitable outside connector used in conjunction with these designs to enable them to be used as general lighting devices.
The Edge type CCFL backlight needs relatively big reflector housing to provide uniform output through the whole surface, which is very important for backlight, but not for general lighting. While the other types of CCFL backlight have flat shapes, but their efficacy is relatively low due to short air discharge passage or too much heat generated during discharging. The third Front type CCFL backlight depends on using low melting point glass as building material, which can easily result in costly vacuum leaks so that it is difficult to maintain high vacuum for high CCFL efficacy.
One aspect of the invention is based on the recognition that a particularly useful and practical CCFL lighting device is provided by employing a serpentine shaped CCFL, a driver driving the CCFL, a connector that allows the device to connect to and receive power form conventional power sockets, and a fixture that connects them into a single device. Such device can be used for general lighting purposes and replaces incandescent and other fluorescent lamps in current use without having to change electrical sockets. According to one embodiment of this aspect of the invention, a CCFL device comprises at least one layer of CCFL, where the layer has at least one CCFL that is serpentine in shape and a driver including at least one CCFL driver supplying AC power to the at least one CCFL to cause it to generate light. At least one fixture supports the at least one CCFL and the driver. A connector is used having a configuration adapted to be electrically and mechanically connected to a conventional electrical socket. The at least one fixture mechanically connecting said at least one CCFL, the driver and the connector to form a unitary mechanical structure. One layer of CCFL means either a complete CCFL or a portion thereof that has a shape that fits into a plate-shaped space.
When the driver is at an elevated temperature, the operation of the driver will be adversely effected. For example, the elevated temperature may adversely affect the magnetic field in a transformer in the driver and damage electronic components in the driver such as transistors and capacitors. By introducing a thermal insulator such as an air gap between the driver and the CCFL, heat transfer from the CCFL to the driver is inhibited, thereby preserving the integrity of the driver and its components, thereby avoiding shortening the useful life of the driver.
According to one embodiment of another aspect of the invention, a CCFL device comprises at least one layer of CCFL, having at least one CCFL having a serpentine shape, a CCFL driver, said driver supplying AC power to the at least one CCFL to cause it to generate light and at least one fixture supporting the at least one CCFL and the driver in a manner such that the driver is separated from the at least one CCFL by at least an air gap. As noted above, the air gap will preserve the integrity of the driver and its components, thereby avoiding shortening the useful life of the driver. A connector is used having a configuration adapted to be electrically and mechanically connected to a conventional electrical socket. The at least one fixture mechanically connects the at least one CCFL, the driver and the connector to form a unitary mechanical structure.
The above embodiment contains at least one layer of CCFL, such layer having at least one serpentine shape CCFL. In one implementation of such embodiment, embodiment also includes one CCFL controller or partial controller containing at least a transformer and its supporting components. One outside electrical connector having a configuration adapted to be electrically and mechanically connected to a conventional electrical socket is used, as well as at least one fixture mechanically connecting said at least one CCFL, the controller and the connector to form an unitary structure.
One embodiment of yet another aspect of the invention includes a heat insulator between a first chamber housing at least one layer of CCFL, having at least one serpentine CCFL with its supporting means, and a second chamber housing a CCFL controller, which contains at least one transformer and its supporting components. One outside electrical connector is used having a configuration adapted to be electrically and mechanically connected to a conventional electrical socket, as well as at least one fixture mechanically connecting said at least one CCFL, the controller and the connector to form an unitary structure. Preferably in this implementation, the unitary structure takes on one of the conventional shapes of lamps, such as that of the MR16, GX53, or PAR type of reflector lamps
The accompanying drawings, which are included to provide further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principle of the invention.
For simplicity in description, identical components are labeled by the same numerals in this application.
One embodiment of the invention provides a high efficacy, high light output, long lifetime, thin profile with good mechanical strength, dimmable and color adjustable flat light source that can be widely used in general lighting applications. It is based on the recognition that by providing a flat housing design, such that heat can be dissipated easily through air circulation of the CCFL in this housing, or thermal conduction through the CCFL supporting material of this housing, so that CCFL can be operated in this housing at a desirable temperature range of ˜70 C and heat generated by the CCFL cannot affect its controlling electronics, which is also housed in the vicinity of the CCFL.
Preferably, most of the length of CCFL 101 is exposed to air at least on the side of CCFL 101 opposite to plate 2, so that the heat generated by the CCFL can be easily dissipated. For low power flat fluorescent lamps, since the heat generated by the CCFL is small, in order to maintain the CCFL at a suitable high temperature, the distance between adjacent segments of the CCFL 101, D, may be selected to be small and both sides of the CCFL may have support plates instead of having a single plate 2. In such event, preferably, the distance D is smaller than twice the outside diameter of the segments of CCFL 101. Support plate 2 preferably is transparent or transmits diffuse light. Alternatively, plate 2 may have a light reflective surface, or has lenses and/or prisms. Connector 5 is in a shape suitable for connection to conventional sockets for general lighting.
Alternatively, device 300 may include two different and separate CCFLs 101a and 101b, so that they may be separately controlled to emit different lighting. In one embodiment of such CCFL device 300, such device comprises at least two CCFLs: at least one with high color temperature phosphor and at least one with low color temperature phosphor, or at least one with low color temperature phosphor and at least one with mixture of green-blue color phosphor. By using one or more drivers to control power supplied to the CCFLs to change the relative light intensities of the light emitted by these CCFL tubes with different phosphors, to obtain different color temperature lights, it is possible to design the device as an adjustable color temperature lamp and/or an adjustable color temperature and dimmable lamp. For example, where three CCFL tubes have red, green and blue phosphors respectively, one or more drivers may be used to control power supplied to the three CCFLs to change the relative light intensities of the light emitted by these CCFL tubes so that the device is a light color variable lamp and/or a light color variable and dimmable lamp.
Frame 9, which can be opened, or closed at both sides of the planar CCFL(s), CCFL(s) 101, its or their driver 7, reflector plate 15, housing 4, outside electrical connector 16 are connected to form an unitary mechanical structure for general lighting.
Alternatively, device 400 may include three different and separate CCFLs 101a, 101b and 101c, so that they may be separately controlled. In one embodiment of such CCFL device 400, such device comprises at least two CCFLs with phosphor of different color temperatures, or at least one CCFL with phosphor of low color temperature and one CCFL with phosphor mixture of green-blue phosphors. By using one or more drivers to adjust power supplied to the CCFLs to change the relative light intensities of the light emitted by the CCFLs with different color temperature, one can obtain different color temperatures, thus, it is possible to design the device as an adjustable color temperature lamp and/or an adjustable color temperature and dimmable lamp.
In addition to using the above CCFL device arrangements 300 and 400 with multiple CCFLs that are separately controlled for general lighting applications, it is also possible to design a CCFL device that generates multi-color (e.g. colors based on the mixture of colors generated by the red, blue and green phosphors) lighting for various applications. For this purpose, two or more CCFLs may be used each having red, green or blue basic color phosphor. A driver circuit converts input electric power to an AC output in the range of about 5 to 400 volts and at a frequency in the range of about 1 kc-800 kc. At least one high voltage transformer responds to said AC output to cause suitable voltage(s) to be supplied to each of the two or more CCFLs to cause the CCFLs to supply light. In one embodiment, a plurality of CCFL lamp units each having two or more CCFLs are used, each unit equipped with its high voltage transformer(s) that supplies a suitable voltage to the CCFL(s) of such unit. Hence, one or more driver circuits applying AC outputs to the two or more CCFL lamp units may apply AC outputs that are different from one another, so that the two or more CCFL units are individually controlled to emit light of the same or different intensities and produce a mixture light of various colors.
Frame 9, which can be opened or closed with or without face plates at both sides of the planar CCFL 101, connects the CCFL 101, its driver 7 and its housing 4, its outside electrical connector 18 to form an unitary mechanical structure for general lighting.
The CCFL 101 is attached to a reflector plate 23 on and attached to the upper housing 32 by means of silicon type of adhesive 3. The CCFL 101 is electrically connected to driver 7 by wires 8. Light emitted by the CCFL 101 is transmitted through a light transmitting or transparent plate 24 in window 13. Plate 24 may comprise a transparent, diffused or patterned material. The electrical connector 5 is the conventional connector for the GX53 type of lamp. The connectors 34 are of such dimension that the two chambers in upper and lower housings 32 and 33 are spaced apart by a thermal insulator such as an air gap 25 to reduce heat transfer from the CCFL to the driver 7. Wire 8 passes through holes in the upper and lower housings 32 and 33 to connect the CCFL 101 to driver 7.
One of the problems encountered in designing a high power fluorescent lamp for replacement of the current high power lamps is that the fluorescent lamp generates an abundance of heat, especially when it is enclosed in a closed chamber. A driver is required to supply the appropriate voltage and currents to the fluorescent lamp causing it to generate light. If the driver that converts low frequency low voltage power to high frequency high voltage power for powering CCFLs is placed in the vicinity of the lamp, the heat generated by the CCFLs may cause the driver components to be at an elevated temperature, which may adversely effect the operation of the driver and shorten the useful life of its components.
When the driver is at an elevated temperature, the operation of the driver will be adversely effected. For example, the elevated temperature may adversely affect the magnetic field in a transformer in the driver and damage electronic components in the driver such as transistors and capacitors. By introducing a thermal insulator such as an air gap 25 in
The CCFL 101 in CCFL chamber 32 shown here preferably has two layers, which can be arranged in directions substantially parallel, perpendicular or transverse to each other. The two layers of CCFL can comprise two different and separate CCFLs having same phosphor or phosphor of different color temperatures. By controlling these two CCFLs through driver 7 can produce high power CCFL or high power CCFL with adjustable color temperature capability as described above in reference to
The CCFL lamp 1100 of
While the invention has been described above by reference to various embodiments, it will be understood that changes and modifications may be made without departing from the scope of the invention, which is to be defined only by the appended claims and their equivalent. All references referred to herein are incorporated herein by reference.
Number | Date | Country | Kind |
---|---|---|---|
200520013482.0 | Jul 2005 | CN | national |
200520013483.5 | Jul 2005 | CN | national |
200520013484.X | Jul 2005 | CN | national |
200520116564.8 | Nov 2005 | CN | national |
200520116919.3 | Dec 2005 | CN | national |