FIELD OF THE INVENTION
- DESCRIPTION OF RELATED ART
The present invention relates to lighting decoration technologies and, more particularly, to light emitting diode (LED) C7 and C9 types bulbs used for lighting and decoration.
Lighting is one of the most important parts of our everyday life. The light bulbs, since invented in 1879, have profoundly changed human existence by illuminating the night and making it hospitable to a wide range of activity. One of the goals of developing lighting technologies is to meet different illumination requirements for different activities, e.g., Living, office, meeting, entertainment, and etc. An efficient lighting structure not only comforts our eyes, but also save electrical power. The second goal of lighting is to decorate the lighted room by shining on the indoor objects and showing their shapes and sizes. For displaying art works, such as pictures, carpets and flowers, lighting is even required to show their colors inside of a room.
Light Emitting Diodes (LED) are semiconductor diodes and belong to the group of electroluminescent luminaries. The light is generated by recombining charge-carrier pairs in a semiconductor with an appropriate energy band gap. The LEDs produce a narrow banded radiation. The properties of LEDs, including their low operating voltage and power, small sizes, long lifetime and great stability, make them desirable lighting sources. The LEDs are cool light source without generating heat and thus are safe for daily operation.
DESCRIPTION OF THE DRAWINGS
However, current C7 and C9 bulbs with either Tungsten filaments or LED solid bulb bodies waste most of electrical power into heat and have a serious optical loss. Meanwhile, limited by LED specifications, the current LED bulbs with C7 and C9 designs have no way to be directly powered by 110-120V AC household power supply. Thus, the applications of LED C7 and C9 bulbs are limited.
FIG. 1 shows the C7 or C9 LED bulb structure. The LED bulb consists of a lamp cover 1, one or multiple numbers of LEDs 2, a PCB circuit board 3, and a base 6. The pins (there are two in the example shown in this drawings, but other LEDs may have more) 5 of the LEDs 2 are soldered onto the PCB board 3 that is embedded inside of the base 6. The voltage input ports 7 of the PCB board 3 are connected to the brass connector 4. The base 6 and the lamp cover 1 may be attached together by bonding (thermal, sonic or solvent), friction interference fit, adhesive or simply by screwing the lamp cover 1 into the threaded base 6.
DESCRIPTION OF THE INVENTION
FIG. 2 shows the PCB electronic circuit diagram. The AC 110-120V voltage input is in series with an RC (resistor R1 and capacitor C1 in parallel) unit and resistor R2 before connecting to a voltage bridge unit that transfers AC to DC voltage. A fuse is used to limit the total current and protect the PCB board and LEDs. A Capacitor C2 and voltage regulator diode DZ1 are wired in parallel to the bridge output to stabilize the voltage on the LEDs. The designed PCB board are capable to drive one or multiple LEDs wired in parallel to meet different requirement of lumens.
The present invention provides a new LED design for C7 and C9 bulbs. The PCB electronic circuit board structure enables LEDs to be directly powered by 110-120V AC power supply, and dramatically reduces power consumption compared to traditional C7 and C9 bulbs.
As shown in FIG. 1, the LED bulb consists of a lamp cover, LEDs, a PCB electronic circuit board, and a brass base or a base made with appropriate material. Different from the traditional bulbs, the bulb of the invention houses the LEDs that are soldered on the PCB board, and the PCB board is embedded inside of the base such that the lamp cover, the LEDs, PCB board, and the base, when fully assembled, forms the invented LED bulb. The PCB board is used here to provide a connection between the internal LEDs and the external 110-120V AC voltage.
FIG. 2 shows the electronic circuit of the PCB board used in the LED bulb. After passing through a capacitor C1 and resistors R1 and R2 (C1 is in parallel with R1, and then in series with R2), the 110-120V AC voltage connects to a bridge unit that transfers the AC into DC voltage. The output voltage from the bridge is stabilized by a capacitor C2 and voltage regulator diode DZ1, in parallel with LEDs (there are three in the example shown in this drawing). A fuse is used to limit the total electrical current, and protect the LEDs and the PCB board.
The lamp cover of the LED bulb may be wholly or partially transparent, translucent, or with a pattern as desired. Standard E12/E14/E17 bases may be applied when C7 and C9 style bulbs are used. As indicated before, the base and the lamp cover may be attached together by means of bonding (thermal, sonic or solvent), friction interference fit, adhesive or simply by screwing the lamp cover into the threaded base.
The LED bulb is mostly empty inside as only LEDs and a small PCB board are housed between the lamp cover and the base. This simple bulb structure greatly reduces light optical absorption loss that is commonly seen in the traditional solid LED bulbs.