Illumination – Plural light sources – With support
Reexamination Certificate
2002-05-16
2004-03-23
Quach-Lee, Y. My (Department: 2875)
Illumination
Plural light sources
With support
C362S800000, C362S363000
Reexamination Certificate
active
06709132
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a light bulb using a plurality of LEDs as light sources.
As conventional lights, light bulbs using tungsten as a filament and fluorescent lamps in which a fluorescent substance emits light by electric discharge in a gas have been generally used. However, since these lights utilize light emission by resistance heat or high-voltage discharge, a large amount of energy is lost as heat energy, leading to lower efficiency in light emission. Therefore, they do not contribute to saving energy. In addition, as a matter of course, filaments break, electrodes are consumed, and sealed gases deteriorate, which shortens product life. Moreover, fluorescent lamps pollute the environment when disposed of because of the toxic substances they contain. Thus, conventional lights have various problems.
On the other hand, LEDs have made rapid improvement in performance. In addition to the development of the white LED, which is indispensable for lighting, LEDs can now emit light sufficiently luminescent for lighting in terms of brightness. Accordingly, a great deal of research is being conducted on the application of LEDs to lighting.
Nevertheless, the disadvantages of the LED are its narrower illuminating angle and difficulty in radiating light uniformly in all directions contrary to the conventional tungsten bulb. As a bulb which emits light only in one direction, a bulb
10
in
FIG. 3
in which a reflector
11
is provided around LEDs
12
has been developed, which, however, cannot be applied as a bulb having no directivity.
In view of the above, one system developed is a bulb
20
shown in
FIG. 4
, having a spherical plastic portion
23
in a form of aggregation of fish-eye lens or polyhedron which covers the front of the emitting portion of LEDs
22
horizontally arranged on a substrate
21
, thereby diffusing light in all directions utilizing refraction of light on the spherical plastic portion
23
.
However, in the system shown in
FIG. 4
, since the number of the LEDs
22
packaged on the substrate
21
is limited, lights having a higher luminance cannot be obtained. Furthermore, the distance between the LEDs and each lens varies depending on the position, thus causing uneven brightness. Therefore, if a plurality of LEDs having a very narrow illuminating angle are disposed on a flat substrate, the illuminating angle of the total system cannot be improved. Even a structure utilizing reflection or refraction of light only enables a very dark bulb with low efficiency.
An object of the present invention is to provide an LED bulb with a higher distribution of luminous intensity which is close to those of tungsten bulbs, in which the problem in directivity of the prior art LED bulbs has been solved while maintaining the advantages of an LED, that is, a long life and an energy saving characteristic.
SUMMARY OF THE INVENTION
In order to solve the above problems, an LED bulb of the present invention comprises a printed circuit board which is flat when developed and is bendable to form a cage, a plurality of LEDs which are disposed on the printed circuit board, and a transparent or semi-transparent cover which encloses the printed circuit board formed into the cage.
The printed circuit board may have a plurality of belt-like branches which extend in radial directions from the center of the printed circuit board.
According to the present invention, by bending a printed circuit board with a plurality of LEDs disposed on the surface thereof to form a cage, thereby providing a light source of a bulb in a small spherical form, direct light of the LEDs can radiate in various directions, which enables light emission in all directions.
By providing a printed circuit board in a shape having a plurality of belt-like branches which extend in radial directions from the center, the board can be manufactured from a flat board and formed into a cage by bending.
If the power source is commercial alternate current, a power source unit for lighting the LEDs is housed inside the bulb, which enables the LED bulb to be used in a manner similar to conventional incandescent lamps.
REFERENCES:
patent: 5585783 (1996-12-01), Hall
patent: 5806965 (1998-09-01), Deese
patent: 6070991 (2000-06-01), Rumpel
ATEX Co., Ltd.
Jordan & Hamburg LLP
Quach-Lee Y. My
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