Source: {"pile_set_name": "USPTO Backgrounds"}

Radiofrequency transmissions may be easily intercepted, in part because of the fact that RF signals are designed to radiate signals in all directions. Radiofrequency transmissions are also regulated by the Federal Communications Commission (FCC) which controls the frequencies that may be used by individuals. Radiofrequency transmissions are also susceptible to interference and produce noise.
In contrast to RF communications, light sources used for communication are extremely secure due to the fact that they are focused within a narrow beam, requiring placement of equipment within the beam itself for interception. Also, because the visible spectrum is not regulated by the FCC, light sources can be used for communications purposes without the need of a license. Light sources are also not susceptible to interference nor do they produce noise that can interfere with other devices.
Light emitting diodes (LEDs) may be used as light sources for data transmission, as described in U.S. Pat. Nos. 6,879,263 and 7,046,160, the entire contents of each being expressly incorporated herein by reference. LEDs have a quick response to “ON” and “OFF” signals, as compared to the longer warm-up and response times associated with fluorescent lighting, for example. LEDs are also efficient in producing light, as measured in lumens per watt. Recent developments in LED technology, such as high brightness blue LEDs, which in turn paved the way for white LEDs, have made LEDs a practical alternative to conventional light sources. As such, LED technology provides a practical opportunity to combine lighting and communication. This combination of lighting and communication allows ubiquitous light sources such as street lights, home lighting, and office building lighting, for example, to be converted to, or supplemented with, LED technology to provide for communications while simultaneously producing light for illumination purposes.
Regarding office buildings, building management is a complex science which incorporates and governs all facets of human, mechanical and structural systems associated with buildings. As a result of the complexity, most commercial buildings are managed by commercial property management companies with great expertise. Both at the time of construction and throughout the life-cycle of a building, the interrelationships between people and the mechanical and structural systems are most desirably evaluated. Where possible and cost-effective, human interactions with a building and associated mechanical systems will be optimized, in turn providing the greatest benefit to both the owners and those who use the facilities afforded by the building. Noteworthy is the fact that building users may include both regular occupants such as individual or commercial tenants, and also transient occupants such as visitors, guests, or commercial customers.
Building management includes diverse facets, some which are simply representations of the building and associated systems and people, and other facets which are tangible. Exemplary of representations are accounting or financial monitoring responsibilities which will including record keeping control and assurance of financial transactions involving tenants, owners, and service providers. Exemplary of the physical or tangible responsibilities are physical development and maintenance, including identification of need for features, improvements, maintenance and the assurance of the execution of the same. As is well understood by those highly versed in building management, the diverse responsibilities and extent of information required to manage a building is often quite overwhelming.
One very important area associated with building management is lighting or illumination. While often perceived as a simple task of providing lights, this seemingly simple task has much research and science behind a well-designed lighting system. This is because safety, productivity and general well-being of occupants depend heavily on proper lighting.
Many factors need considered at the time of construction or remodeling to facilitate proper lighting design. Intended usage of a space is important in illumination design consideration, since this will dictate necessary illumination levels, times and duration of use, and anticipated cycling of the illumination. In other words, a supply closet will not ordinarily be designed for around-the-clock illumination, and may instead be configured to operate on a switch. The use of appropriate switches helps to reduce the energy required for a building to function with occupants, and simultaneously increases the life of many illumination components such as light sources (light bulbs and equivalents thereto) since the light sources are only required intermittently. As another example, a room where movies, slides, computer or other visual or audio-visual presentations are given, such as a boardroom or classroom, will preferably have light controls such as separate switches or switches and dimmer controls which enable the entire room to be well lit or alternatively maintain a minimum level of illumination normally opposite to where the presentation is displayed. This minimum level of illumination enables occupants sufficient light for note-taking, safe movement and other important activities, without interfering with the legibility of a presentation. In yet another example, a primary work-space such as a desk or kitchen counter will require illumination that does not cast shadows on the work space while work is being performed. Complementary illumination, such as windows or skylights, is also important in design consideration.
Nearly all public buildings rely on a great many lamps positioned throughout the interior of the building, such as along hall corridors and in each room, and also about the exterior. These lights have historically been activated manually. Architects are commonly employed to assist not only with a floor plan of physical spaces, but also with the proper selection and layout of lighting to best complement the floor plan and usage of each space within a building. As may be appreciated, illumination of a space is determined at the time of production of blueprints, in anticipation of construction. The illumination that has been chosen for a space is essentially fixed during building construction. Changes may be made later, but not without substantial additional expense that will, for exemplary purposes, often include removal of parts of or entire walls, with the accompanying disruption of the space. Often the space is unavailable for use during the entire duration of a remodeling project.
Further complicating the issue of illumination is the type of light bulb that may be most appropriate for a space or location. Original electric light bulbs were incandescent. With sufficient electrical energy, which is converted to heat within an incandescent bulb filament, the filament will emit visible light. This is similar to a fire, where with enough heat, visible light is produced. As might also be appreciated though, incandescent bulbs produce far more heat than light. The color of the light from these bulbs is also most commonly quite yellow, casting a warm hue at a color temperature typically in the vicinity of 3,000 degrees Kelvin. Warm hues are often prized in relaxed settings such as those of a living room or dining room, more closely resembling gentle candle light. However, in contrast thereto, work and study environments are more preferably illuminated with light of more blue content, more closely resembling daylight with color temperatures of approximately 6,000 degrees Kelvin. Daylight color temperatures are not practically obtained using an incandescent bulb. In addition, these incandescent bulbs have only a few thousand hour life expectancy, even with more than a century of improvements, because the extreme temperatures required for the filament to light also gradually evaporates the filament material. Finally, the thermal mass of the filament greatly influences how quickly the filament both illuminates and extinguishes. In spite of the many limitations, incandescent bulbs are still in fairly wide-spread use today.
An alternative to incandescent light bulbs in common use today is the fluorescent bulb. A fluorescent light bulb uses a small amount of mercury in vapor state. High voltage electricity is applied to the mercury gas, causing the gas to ionize and generate some visible light, but primarily UltraViolet (UV) light. UV light is harmful to humans, being the component that causes sun burns, so the UV component of the light must be converted into visible light. The inside of a fluorescent tube is coated with a phosphorescent material, which when exposed to ultraviolet light glows in the visible spectrum. This is similar to many glow-in-the-dark toys and other devices that incorporate phosphorescent materials. As a result, the illumination from a fluorescent light will continue for a significant time, even after electrical power is discontinued, which for the purposes of the present disclosure will be understood to be the latent period or latency between the change in power status and response by the phosphor. As the efficiencies and brightness of the phosphors has improved, so in many instances have the delays in illumination and extinguishing, or latency, increased. Through the selection of ones of many different modern phosphorescent coatings at the time of manufacture, fluorescent bulbs may manufactured that produce light from different parts of the spectrum, resulting in manufacturing control of the color temperature, or hue or warmness of a bulb.
The use of fluorescent bulbs, even though quite widespread, is controversial for several reasons. One source states that all pre-1979 light ballasts emit highly toxic Polychlorinated BiPhenyls (PCBs). Even if modern ballasts are used, fluorescent bulbs also contain a small but finite amount of mercury. Even very small amounts of mercury are sufficient to contaminate a property. Consequently, both the manufacture and disposal of mercury-containing fluorescent tubes is hazardous. Fluorescent lighting has also been alleged to cause chemical reactions in the brain and body that produce fatigue, depression, immuno-suppression, and reduced metabolism. Further, while the phosphor materials may be selected to provide hue or color control, this hue is fixed at the time of manufacture, and so is not easily changed to meet changing or differing needs for a given building space.
Other gaseous discharge bulbs such as halide, mercury or sodium vapor lamps have also been devised. Halide, mercury and sodium vapor lamps operate at higher temperatures and pressures, and so present undesirably greater fire hazards. In addition, these bulbs present a possibility of exposure to harmful radiation from undetected ruptured outer bulbs. Furthermore, mercury and sodium vapor lamps generally have very poor color-rendition-indices, meaning the light rendered by these bulbs is quite different from ordinary daylight, distorting human color perception. Yet another set of disadvantages has to do with the starting or lighting of these types of bulbs. Mercury and sodium vapor lamps both exhibit extremely slow starting times, often measured