Electric lamp and discharge devices: systems – Discharge device and/or rectifier in the supply circuit – Flashers
Reexamination Certificate
2000-09-08
2001-05-29
Wong, Don (Department: 2821)
Electric lamp and discharge devices: systems
Discharge device and/or rectifier in the supply circuit
Flashers
C362S205000, C362S208000
Reexamination Certificate
active
06239555
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a new and improved flashlight and more specifically to a flashlight which uses a semiconductor diode as a source of light.
It has been suggested that a flashlight may use either a red or green light emitting diode in place of a conventional bulb. When a mechanical switch is actuated, the light emitting diode is energized by a battery in the flashlight. A flashlight having this construction is disclosed in U.S. Pat. No. 4,290,095.
It has previously been suggested that a flashlight could have springs which drive a generator to provide power. The output from the generator is used to energize a conventional light bulb. A flashlight having this construction is disclosed in U.S. Pat. No. 3,099,402.
A flashlight having a light emitting diode which periodically flashes to aid in finding the flashlight in the dark is disclosed in U.S. Pat. No. 4,228,484. The flashlight disclosed in this patent has a battery which energizes a conventional light bulb when a mechanical switch is actuated. The light emitting diode continuously flashes when a battery is disposed in the flashlight.
SUMMARY OF THE INVENTION
The present invention provides a new and improved flashlight, that is, a battery-operated portable electric light, having a semiconductor diode which is capable of emitting light when energized. Electrical circuitry interconnects the diode and a source of power which may be either a battery or a generator.
The electrical circuitry includes a switch which is operable between a first condition and a second condition. When the switch is in the first condition, the diode is energized to provide light of a low intensity to facilitate locating the flashlight. When the switch is in the second condition, the diode is energized to provide light of a high intensity which may be sufficient to illuminate objects spaced more than six feet from the flashlight. The diode may emit white light when energized.
The electrical circuitry may include a manually movable member. Upon actuation of the manually movable member, a transistor or other semiconductor device is switched between conducting and nonconducting states. The light emitting diode is changed between a condition in which it is energized to emit high intensity white light and low intensity white light in response to actuation of the transistor between the conducting and nonconducting states.
A regulator is advantageously connected with the diode and the source of power to maintain the intensity of the white light emitted from the diode substantially constant. When the diode is energized to provide high intensity white light, the regulator is effective to maintain the intensity of the white light constant even though the strength of the source of power connected with the diode decreases. This enables white light of a uniform intensity to be obtained from the light emitting diode even though a power source which gradually discharges with the passage of time is used to energize the light emitting diode.
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Tarolli, Sundheim, Covell Tummino & Szabo L.L.P.
Tran Thuy Vinh
Wong Don
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