Electric lamp and discharge devices: systems – Automatic substitution of the power supply
Patent
1982-06-01
1984-11-20
Dixon, Harold
Electric lamp and discharge devices: systems
Automatic substitution of the power supply
136291, 315149, 315307, 362812, H02P 300
Patent
active
044841043
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a solar powered lighting system, suitable for illuminated signs, billboards and hoardings powered by the system which may be used for advertising purposes.
Roadside billboards are well-known and are a common sight along the sides of highways or major roads, being either free-standing or mounted on walls or building structures. While they are an effective advertising medium during daylight hours, their effectiveness is almost zero at night unless some method of illumination is provided. In remote locations, or along highways, it is often not economically feasible to supply electricity to these billboards to enable them to be illuminated.
In cities or towns, where an electricity supply is available, the illumination of the billboards and hoardings may be direct, e.g. by lights mounted in front of the billboards or hoardings with their light directed thereonto, by neon tubes or fluorescent tubes formed into particular shapes or configurations, or indirectly, by illuminating the rear of the panels carrying the materials, where the panels may be selectively transparent or opaque.
It is an object of the present invention to provide a solar-powered lighting system.
It is a preferred object of the present invention to provide an illuminated sign, billboard or hoarding which has an integral power supply which provides electricity generation by way of solar cells.
It is a preferred object of the present invention to provide means to selectively illuminate the lights of the sign, billboard or hoarding when visibility is below a preset minimum and/or for a predetermined time period.
It is a further preferred object to provide a power supply which, with minor modification, can be used with either A.C. or D.C. lights.
It is a still further preferred object to provide a power supply which may be used in conjunction with a main electricity supply, the present invention providing an emergency or "back-up" supply.
Other preferred objects of the present invention will become apparent from the following description.
In the broad aspect, the present invention resides in a solar-powered lighting system for illuminated signs and hoardings including:
a plurality of solar cells arranged in an array to receive solar energy;
battery means to store electrical energy generated by the solar cells;
light means operable by the electrical energy; characterized by:
sensing means operable to control the illumination of the light means dependent on the light intensity in the vicinity of the sign or hoarding.
Preferably the sensing means is interposed between the battery means and the light means and includes a light sensitive component which switches on the light means when the light intensity falls below a preset minimum value.
In one preferred form, the sensing means includes:
a light sensitive resistor;
a transistor biassed by said resistor;
a relay connected to the transistor, the relay being normally open isolating the light means from the battery means;
the components being arranged so that when the light intensity incident on said resistor falls below the present minimum value, the transistor is switched to operate the relay to interconnect the light means to the battery means to illuminate the sign.
In an alternative form, the sensing means includes:
a photovoltaic cell;
a silicon-controlled rectifier having its gate connected to the output of the photovoltaic cell; and
a relay connected to the rectifier and normally open isolating the light means from the battery means;
the components being arranged so that when the light intensity incident on the photovoltaic cell falls below the preset minimum value, the rectifier is switched to close the relay to interconnect the light means to the battery means to illuminate the sign.
Preferably a battery voltage regulator is provided between the solar cell array and the battery to regulate the voltage and current generated by the solar cell array.
A timing means, e.g. a time clock, may be provided to cause the sign to be illuminated for a predetermined period or period
REFERENCES:
patent: 1003724 (1911-09-01), Felver
patent: 3486068 (1969-12-01), Dunn et al.
patent: 3739226 (1973-06-01), Seiter et al.
patent: 3860863 (1975-01-01), Lamprecht
patent: 4009051 (1977-02-01), Kazis et al.
patent: 4009535 (1977-03-01), Stock
patent: 4283657 (1981-08-01), Gordon et al.
patent: 4314198 (1982-02-01), Rogers
patent: 4384317 (1983-05-01), Stackpole
"Solar Panel for Terrestrial Applications" by Franx Electronic Component & Applications, vol. 1, Part VI, Feb. 1979, pp. 109-124.
Conference Record of IEEE Photovoltaic Specialist Conference 1978 "Description . . . Photovoltaic Experiment" by Ratajczak, pp. 1272-1277.
Dixon Harold
Weaver D. Paul
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