1. Technical Field
The invention relates to decorative lighting and more particularly to a lantern housing an electrically powered imitation flame source.
2. Description of the Problem
Many people find candle and gas light pleasant. The flickering of light and movement of shadows across nearby surfaces generated by an open, flickering flame can be almost hypnotically soothing. As a result, candles have remained popular for generations since the invention of more practical electrical lighting, especially for decorative and mood setting purposes. This has remained so notwithstanding the hazard posed by open flames, the short service life of candles and the expense of supplying gas to exterior lamps.
Numerous electrically powered lamps have been proposed in the art intended to produce an impression of an open flame. Some lamps have included bulbs with plates producing irregular, low level electrical arcing while other lamps have been shaped as candles and topped with flame shaped bulbs. Producing an impression of realism however requires an appreciation of the conditions under which the device is used and the likely distances at which it is commonly viewed. Where the device is intended to resemble a candle a number of factors should be considered. These include the color of the light and the intensity of the light. The way in which the body of the candle picks up and scatters light can be critical to producing an impression of a flame.
In U.S. Pat. No. 6,616,308 the inventors of the present application proposed an imitation candle incorporating a super bright, light emitting diode (LED). Super bright LEDs function as highly directional, near point sources. An emission color, such as amber, is selected for the LED to produce a light similar in color to that of a paraffin fed flame. A simple circuit using multiple oscillators running at close, but not the same, frequencies, creates a realistic, pseudo-random flicker for light emitted by the LED.
The body of the imitation candle of the '308 patent is preferably a translucent material. The translucent material surrounds the LED on the sides and top and serves to diffuse the light throughout the portion of the imitation candle at or above the height of the LED. The LED is positioned near the top of the body and causes the top of the imitation candle to be more brightly illuminated than the lower parts of the candlestick. This effect can be enhanced by positioning an opaque light block around the base of the LED to prevent diffusion of light into the lower portions of the imitation candle. These steps simulate the usual diffusion of light in a real candle. Recessing the top within the side walls presents the appearance of a candle that has already been burning for some length of time, which would serve to hide the flame behind an unmelted rim, were a flame present. The body of the imitation candle is preferably made from real wax to further enhance the imitation candle's realism.
The power consumption of super bright LEDs operated at low emission levels is low enough that long battery life can be achieved. Alternatively, rechargeable cells can be used in conjunction with a solar cell or other recharging means. A simple light sensing device can be used to turn the LED off during daylight hours and extend battery life in battery operated versions of the candle.
While the imitation candle taught in the '308 patent has been highly successful, different considerations come into play in producing a lantern intended to be electrically illuminated, but none-the-less giving the impression of having a flame source. Lanterns are often intended to serve both functional and decorative purposes. They tend to be seen from greater distances and provide an enclosure for the light source. These factors suggest that straight application of an imitation candle to a lantern, while potentially satisfactory, may be improved upon.