- Lecture Power Point
- Printable Notes
- Project 3 Due
- Reading Due: Architecture of Light - Chapter 8
GE Lighting has a nice feature on their website, gelighting.com, that provides a good method of comparison for source color temperature. The color booth website (click here) provides various images that can be viewed side-by-side, and display scenes lighted with different color temperature sources.
Keep in mind when viewing these images, the actual color that would be perceived by the eye is very difficult to capture with a camera. Additionally, the color settings of the monitor or printer used to view these images may not be calibrated. The comparison method should be used to get an idea of differences between sources, not to actually measure how well a source may render a particular color.
Osram-Sylvania’s new electrodeless lamps caught my eye. Apparently, they released the product over a year ago, according to a press release issued by OSI.
Electrodeless fluorescent lamps, commonly know as induction lamps, offer longer life over standard fluorescent technology. For more information about this technology, see the Licoda.com article, How Induction Lighting Works.
You can view a product information sheet at the following link: http://www.sylvania.com/content/display.scfx?id=003683538
As noted in the article, if you have a high maintenance application that requires long lamp life, then the high initial cost of an induction lamp may be justified for the application.
The basic technology for induction lamps is not particularly new. Essentially, an induction lamp is an electrodeless fluorescent. Without electrodes, the lamp relies on the fundamental principles of electromagnetic induction and gas discharge to create light. The elimination of filaments and electrodes results in a lamp of unmatched life. Lasting 100,000 hours or 25 years, this system can outlast 100 incandescent, five HID, or five typical fluorescent lamp changes.
Based on these well-known principles, light can be generated via a gas discharge through simple magnetism. Electromagnetic transformers, which consist of rings with metal coils, create an electromagnetic field around a glass tube which contains the gas, using a high frequency that is generated by an electronic ballast. The discharge path, induced by the coils, forms a closed loop causing acceleration of free electrons, which collide with mercury atoms and excite the electrons. As the excited electrons from these atoms fall back from this higher energy state to a lower stable level, they emit ultraviolet radiation. The UV radiation created is converted to visible light as it passes through a phosphor coating on the surface of the tube. The unusual shape of an induction lamp maximizes the efficiency of the fields that are generated.
Although it is not breakthrough science, until recently, it has not been so commercially viable. New developments have broken down the barriers of costs and technological setbacks, such as EMC interference, lumen depreciation, ability to dim and a useful range of available wattages. Today, its obvious benefits make it the clear-cut choice for many lighting applications over traditional light sources.
For more information on how inducting lighting works, visit the fluorescent induction lighting section of the electrodeless lamp entry at Wikipedia.com.
Belfer Lighting has a great guide to help designers ensure a successful cove application. The guide starts on page 4 of the Belfer compact fluorescent catalog section (download here) and provides a detailed checklist.
Cove lighting is a method of integrating luminaire(s) into a shelf-like architectural feature. Coves typically conceal the luminaires and leave a simple reveal of light. In addition to providing an architectural accent, uplight coves can provide uniform lighting for soft and comfortable scenario.
Of particular interest is the portion of Belfer’s cove guide that deals with shadows. Often coves are designed or built too small or with sources too close to surfaces producing socket shadows.
Socket shadows break-up the desired uniformity of a cove and can be considered sloppy or haphazard. Belfer has provided some examples to minimize socket shadows.
Obviously, these examples are geared toward Belfer products. However, I believe a rule of thumb could be applied.
Cove sources should be installed at a minimum distance from the nearest visible surface. That distance depends on the spacing between luminous surfaces within the luminaire (labeled “X” in Figures 1, Figure 3 and Figure 5). The minimum distance from the cove luminaire to the nearest surface should be at least twice the spacing to ensure that excessive “hot spots” are not developed. Refer to the “2X” dimension indicated in Figure 2 and Figure 4.