The present invention relates generally to the field of illumination, and, more particularly, to a submersible color light. Although the present invention is subject to a wide range of applications, it is especially suited for use in a pool lighting system, and will be particularly described in that context.
Pool lights illuminate the water at night for the safety of swimmers and for aesthetic purposes. The illumination emanates from underwater lights affixed to the wall of the pool. As used herein, a pool is used generically to refer to a container for holding water or other liquids. Examples of such containers are recreational swimming pools, spas, and aquariums.
To enhance the aesthetics, some current underwater pool lights use a transparent color filter or shade affixed to the front of the lens of the pool light to filter the light emanating from the lens of the pool light and thus add color to the pool. The color filters come in a variety of colors but only one of these color filters can be affixed to the pool light at a given time. Thus, the color of the pool stays at that particular color that the color filter passes. In order to change the color of the pool, the color filter must be removed from the pool light and a different color filter installed across the lens of the pool light.
As a alternative to these fixed colored filters, a system has been devised whereby a rotating wheel having filters of several colors is provided, such as the system disclosed in U.S. Pat. No. 6,002,216 and incorporated herein by reference. In this arrangement, white light is provided from a single source to at least one fiber optic lens through an optical fiber. Colored light is emitted from each fiber optic lens by passing white light through the color filter wheel which is selectively rotated by a motor in the illuminator. The color of light emitted by multiple illuminators is synchronized by independent circuitry within each illuminator that responds to digital signals in the form of manually interrupted supply current.
However, fiber optic underwater illumination systems have several limitations that lead to the need for the present invention. The first is that their performance is relative to the skill of the installer. Only a well-trained technician is capable of installing a fiber optic system that can adequately illuminate a swimming pool. The availability of qualified training is limited thus the availability of trained installers is limited. Rushed fiber termination or fiber termination performed by an untrained installer can result in more than a 30% decrease in fiber optic system performance and can ultimately result in a costly failure of the total fiber optic system.
The second disadvantage of underwater fiber optic illumination is the limited amount of light delivered to the pool. This results from the light attenuation over distance that is inherent in the fibers' composition and the inefficiencies of focusing available light into the optical fiber at the light source.
A further drawback of fiber optic underwater illumination is in the possibility of retrofitting the millions of existing pools having traditional submersible incandescent lighting fixtures. The feasibility of installing adequately sized fiber optic cable in the existing conduits is limited. These conduits are commonly ½ inch in diameter and are rarely over one inch in diameter. The minimum conduit diameter to carry a single fiber optic cable capable of delivering minimally acceptable light to a pool is one inch and the recommended size is 1½ inches.
An additional limitation of fiber optic systems is the additional cost of the materials and professional installation.
The alternative to colored fiber optic systems, providing colored lenses to submersible incandescent lighting fixtures, can be troublesome as well. These fixtures can be supplied with a colored glass lens to deliver that specific color to the pool. These colored glass lenses are typically limited to how richly they can color the light because the darker (or richer) the lens color, the more light in the form of heat that is trapped in the lens and the fixture. As the lens becomes too hot by absorbing too much light it can break due to thermal expansion or due to the differences in thermal expansion on the hot interior surface of the glass and the cool exterior surface that is in contact with the water. Further, as a result less light is emitted and it may be insufficient to illuminate the pool.
As an alternative to glass lenses, snap on or twist lock plastic colored lenses can be installed over an existing clear glass lens for a considerably simpler method to changing the color of the pool lighting. This method still requires physically lying or kneeling on the edge of the pool an reaching below the water to remove the existing plastic lens and then reaching again into the water to install the next colored plastic lens. Economical transparent colored plastics are also inefficient light transmitters reducing the amount of colored light reaching the pool.
A need therefore exists for pool lights that can easily replace existing self-contained, incandescent lighting fixtures, but having synchronized color wheels without the additional cost of installing fiber optic cables and other drawbacks associated with fiber optic underwater illumination systems. Further, a need exists for colored lenses to be used with incandescent fixtures that do not trap excessive amounts of light and heat.