Illumination – Light source and modifier – Including translucent or transparent modifier
Reexamination Certificate
2000-03-24
2001-12-11
O'Shea, Sandra (Department: 2875)
Illumination
Light source and modifier
Including translucent or transparent modifier
C362S800000, C362S327000
Reexamination Certificate
active
06328456
ABSTRACT:
FIELD OF INVENTION
The present invention relates to an illumination apparatus and improved light emitting diode lamp (LED) having a unique configuration adapted to distribute radiated light energy over a wide viewing angle. More particularly an illumination apparatus using at least one LED to create a beam of light and an LED configured to direct light over a wide viewing angle and into a reflector to create a beam of light.
BACKGROUND OF THE INVENTION
Heretofore beam lights, such as flashlights and the like, have generally used an incandescent bulb and a reflective surface to create a beam type lighting pattern or a collimated beam of light for general purpose use as a source of illumination. The bulbs give off light in a spherical pattern which ensures that a significant amount of light is reflected off the reflective surface surrounding the bulb, to create a beam of light. While these incandescent bulbs provide relatively uniform sources of a broad, visible spectrum of light, there are several problems that exist when using these bulbs in applications such as in a flashlight.
Incandescent bulbs are relatively inefficient which results in large amounts of entrapped heat energy, shortened life of the bulbs, and relatively high energy consumption of the batteries. The light produced from the incandescent bulbs is generally yellow and gives a yellowish tint to anything viewed by the flashlight. The incandescent bulbs are fragile and susceptible to breaking due to shock loads such as when the flashlight is accidentally dropped. The bulb life can also be limited by hot and cold temperature as well as vibrational effects. Additionally, because incandescent bulbs are inefficient in operation, there are increased operating costs.
Most recently, semiconductor LED lamps have been used in flashlight applications. An LED is essentially a PN junction semiconductor diode that emits light when a current is applied. The LED is a solid state device which operates at a low current and produces negligible heat. The LED is encapsulated in a resin material which protects the device making it durable and long lasting. The use of conventional semiconductor light emitting diodes solves the problems of entrapped heat, lamp longevity, frequent lamp replacement and higher current operation.
However, the light produced by current LED bulbs have a limited effective range, the small viewing angle created by the diode projects the light in a fashion such that when used in a flashlight or like device, the majority of the light does not hit the reflective surface of the flashlight's reflector. In addition, when an LED is simply inserted in place of an incandescent bulb, the LED lamp life is shortened because the current applied is in excess of what the lamp was designed to operate at. In general, simple replacement with a conventional LED into a typical flashlight will operate at 100-120 mA, while LED's are typically designed to operate below 30 mA. Another problem that exists when using conventional light emitting diodes is that of a non-uniform distribution of emitted light energy.
Shown in
FIG. 1
is a sectional view of a conventional LED lamp having one or more semiconductor chips
150
. The transparent envelope
100
has a convex hemispherical shaped lens
120
, located at the end of a cylindrically shaped rod
140
. A semiconductor chip
150
is mounted to the conductive surface of the first electrode, LED anode
110
, within the convex reflector
140
. A fine wire
130
connects the opposite end of the semiconductor chip
150
to the second electrode
120
. Also shown is the cone shaped light pattern
160
that is emitted from this LED device. A beam of visible light projects in a cone that ranges in angularity from
12
to 36° dependent upon the intended design usage.
The viewing angle
2
of the emitted light and visibility of the light produced by the diode
1
shown in
FIG. 1
is relatively small making the device useful for indicators, and in some close range applications such as penlights or the like. In order to overcome this problem, some prior art devices use a cluster of LED's mounted together in an attempt to create stronger intensity light. These devices consume more energy, produce more heat, and are subject to produce dark spots due to averaging effects of the beams of light.
Therefore, there is a particular need for a light emitting diode lamp that provides a source of radiant energy that is adapted to distribute the radiated light energy onto a reflector to create a beam type lighting pattern and/or a collimated beam of light.
SUMMARY OF THE INVENTION
The present invention is directed to an LED lamp and method of using one or more lamps, and portable lighting products such as flashlights, lanterns, portable work lights, spotlights, vehicle headlights or other similar applications. The LED lamp according to the invention provides uniformly distributed light that radiates spherically at angles greater than 180°, for example up to approximately 270° in all directions, both radially and axially. This newly designed lamp is ideally suited as a source of illumination for beam lights of the type employing reflective surfaces to produce a beam of light.
The preferred embodiment of the LED lamp that radiates light uniformly in a spherical pattern comprises, at least one semiconductor chip coupled to a source of electrical power. The at least one chip is encased in at least one envelope surrounding the chip, with the envelope extending from a first position below the position of the at least one chip to a second position above the chip position. The second position of the envelope forms a lens in front of the at least one chip with the surface of the lens being configured and positioned relative to the chip such that a substantially uniform portion of light emitted from the chip is reflected off of the surface. In this manner, that light is radiated spherically over an angle greater than 180° and up to 270° relative to the chip position. Also, in the preferred embodiment, the envelope is formed as a cylinder at its lower portion and the lens is formed as a transitional surface extending from a position equal to or below the position of the chip at an angle or curvature inward from the cylindrical portion to encase the chip. It is also desirable that the angle of curvature of the surface at the position of the chip, be less than 70° with respect to the cylindrical surface of the lower portion. In the preferred embodiment, the lens is formed at a position directly above the chip, at a distance between greater than zero inches to about 0.1875 inches, and more preferably between about 0.030 inches to about 0.080 inches.
These and other advantages of the present invention will become more apparent upon further reading of the detailed specification. It should be understood that deviations or modifications can be made without deviating or departing from the spirit of the present invention.
REFERENCES:
patent: 4967330 (1990-10-01), Bell et al.
patent: 5289082 (1994-02-01), Komoto
patent: 5865529 (1999-02-01), Yan
patent: 5897195 (1999-04-01), Choate
patent: 5947588 (1999-09-01), Huang
Hahn Loeser + Parks LLP
Ledcorp
O'Shea Sandra
Oldham Scott M.
Truong Bao
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