LED AND YOUR SIGN
Major Advances In Electrical Engineering And Chemistry Were Necessary To Bring Us The Current Revolution In The World Of Light
That Is The Light Emitting Diode
In the simplest of terms, a Diode is an electronic device that works as a gate to allow electrical current to run one direction but not the other. By preventing the current from flowing in one direction, the excited Electrons, that combine to create electricity, are forced to interact with the chemicals and materials that make up the Diode’s surfaces. This electro-chemical interaction with the Diode changes the way the Electrons orbit around the nucleus of their atoms. When the orbit of an electron around the nucleus of an atom gets smaller, energy is released. This energy is in the form of photons which we perceive as light. The energy that is released, on a molecular level, is directly related to the wavelength of light that we perceive with our eyes. Since white light is a combination of the entire color spectrum, creating white light was especially difficult for early pioneers in LED technology. Some LED’s create white light by combining the colors of Red, Green & Blue (RGB). This process was not as efficient as using chemistry to create the desired white light. By using chemical phosphors, similar to the technology in fluorescent lighting, engineers were able to create very efficient, high output white light which is the Holy Grail of LED technology. Here are some basic advantages and disadvantages of LED lighting:
- LEDs emit more light per watt than incandescent light bulbs. The efficiency of LED lighting fixtures is not affected by shape and size, unlike fluorescent light bulbs or tubes. This translates into much lower operating costs over time.
- Since the color of the light emitted by LEDs is created at the source, based on the diode’s chemistry, there is no need to filter the light to create other colors. This enables LED’s to maintain their light output no matter the colors involved in the sign.
- LEDs can be very small (smaller than 2 mm) and are easily attached to printed circuit boards.
- LEDs light up very quickly. A typical LED achieves full brightness in under a microsecond.
- LED’s do not mind being turned on and off frequently. This makes them perfect for signs with sequenced light shows that are very effective at drawing attention to your business.
- There are multiple ways to control the light output of the LED circuit. Traditional methods of reducing the amount of current in the LED circuit work with LED’s and it is also possible to rapidly turn them off and on at different intervals. By leaving the LED’s off for longer than they are on, you can reduce the overall brightness of the sign. This is called Pulse-Width Modulation. This Pulse-Width Modulation is why LED lights, particularly headlights on cars, when viewed on camera or by some people, seem to flash or flicker. This is a type of stroboscopic effect.
- Unlike incandescent lighting, there is very little heat released as infrared radiation. LEDs radiate very little heat in the form of IR that can cause things to burn if they get too hot. The heat generated by LED’s is released through the base of the diode. Higher output LED’s need a “Heat-Sink” to help dissipate this extra energy and keep them running cool.
- LEDs will usually just dim over time instead of the quick burn out of incandescent bulbs.
- LEDs have a very long useful life. Most LED modules, used in signs, will last 50,000 hours before they start to dim noticeably. Typically, the power supply or other materials will fail before you will notice your sign getting any dimmer. Fluorescent tubes are typically rated at about 10,000 hours and incandescent light bulbs only last 1,000 to 2,000 hours. The life of these older technologies is often shortened even further given the environment that a sign lighting system must endure. Another reason why LED’s are perfect for sign illumination. Because of the “Solid-State” nature of LED lighting circuits, it is often the reduced maintenance costs that make LED lighting so attractive. Reduced maintenance costs can even outweigh the savings in energy that you will gain from an LED illuminated sign.
- LEDs, being solid-state components, are difficult to damage with external shock, unlike fluorescent and incandescent bulbs, which are much more fragile.
- The solid package of the LED can be designed to focus its light. Incandescent and fluorescent sources often require an external reflector to collect light and direct it in a usable manner.
- While traditional light sources radiate heat and can have a significant impact on their environment, LED’s must dissipate heat through the base of the diode itself. LED’s are consequently subject to failure if their environment becomes too hot and the LED’s are not designed to effectively dissipate heat through their base. A quality design provides for heat to be drawn away with a “heat Sink” using metal or other materials that quickly absorb heat.
- LED’s are sensitive to the current that drives them. If the voltage is too high, it will impact the diode’s life span. Most modern power supplies are designed to control the voltage to maintain a consistent, controlled power output.
- Electrical engineers have struggled with finding the right combination of phosphors to help render colors the same way the sun and incandescent lighting render colors. Depending on the LED, red and green surfaces are the most difficult colors to illuminate in a consistent manner.
- Single LED’s do not spread out the light they generate in all directions. This lack of light dispersion is overcome by adding light diffusing lenses over the top of the diode itself.
- LEDs are much more attractive to insects than some other traditional forms of outdoor lighting. The Light output of LED’s near beaches has confused turtle hatchlings in the past so the use of “Turtle-safe lighting” LEDs that emit only at narrow portions of the visible spectrum is encouraged by conservancy groups in order to reduce harm.
- Since they do not give off much heat in comparison to incandescent lights, LED lights used for traffic control can have snow obscuring them, leading to accidents.
When it comes to using LED’s in sign manufacturing, the advantages far outweigh the disadvantages. The lower maintenance and power costs are just a couple reasons why LED’s have virtually eliminated all other forms of sign illumination. Their form factor also allows our sign designers to get very creative in the way signs are illuminated. All these factors have revolutionized the sign industry over the past couple decades. Signs Plus uses only the highest quality LED modules in our sign production. You can rest assured that every illuminated sign that we produce will reduce your maintenance and power consumption costs right from the start. Just let us know how we can help you illuminate your brand and we will get to work designing, manufacturing and installing your new sign today!