(Cover Story) Solar Powered Display

Our most exhaustible and stupendous potential source of energy‹he sun‹was harnessed to a unique design when Charles Eames created the "Solar Toy," shown on our cover, for the "Forcast Collection" of Aluminum Company of America.

Intrigued by the possibilities of a future where man would use an energy source 93-million miles distant, Eames fashioned a design so that people may "see a living demonstation of the fantastic potential of the work that solar energy can perform for mankind."

The Solar Toy, performing no function in itself, amply demonstrates the potential of the sun as it converts solar into electrical energy to turn wheels, spin crankshafts, and create optical illusions.

Heart of the unit is a bank of silicon solar cells. Mounted in a reflector unit, oriented toward the sun by a unique tracking device, the cells are practical photovoltaic devices, capable of directly converting radiant or solar energy into electrical power or useful proportions.

Cells used are of the "p-n" type. The junction is formed on the wafer surface that is exposed to illumination and is composed of "n"-type semiconductor materials.

The "p"-type and "n"-type silicon are separated by a microscopic barrier layer, in which a built-in, permanent electrical field exists. Current flow from this field occurs when light is absorbed by a silicon crystal, causing movement and displacement of electrons and holes. Subsequently, a voltage difference is created at the "p-n" junction between the silicon layers of the cell and an electric current is produced.

A group of solar cells, arranged in a series-parallel configuration designed to give optimum power transfer to the load, becomes a solar battery. Power generated in excess of operating needs may be fed to storage batteries for use during periods of darkness or overcast skies.

On Eames' Solar Toy, the converted energy drives a group of seven, motors. The tiny, 1 1/2- to 3-volt motors are each connected directly to a drive or cranskshaft of the Toy.

The purpose of Alcoa's "Forecast" program, in which Eames' design was the eleventh creation, is to commission great designers to predict problems for tomorrow and solve them now, imaginatively, thought great design in aluminum. The program is broadly concerned with design for the home and family. Alcoa has gone wherever the imagination sufficient to do the task exists; to a Paris couturier, a graphic artist, sculptor, painter, and architect.

It is reasonable to assume that the sun, both as an energy source and as an intimate part of man's environment, will be a concern in several future "Forecast" designs. Charles Eames has pointed the way with his ultimately functional, functionless Solar Toy.

photograph by The Aluminum Company of America

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