LED Technology¹
Introduction
LED has become increasingly important the past few years due to its many implications. One significant use is in lighting up some of the flow art props detailed in the website. Granted flow artists can give nighttime performances with fire, it is usually not ideal for beginners or overall safety. Rather, LEDs are preferred because they accentuate an artist's movements and also his or her creative style given the spectrum of customizable colors, effects, and patterns. But to end this argument on just flow arts would be foolish, since LEDs are in our everyday life.
What are LEDs?
Light-emitting diodes (LEDs) consist of a semiconductor material that releases photons, or light particles, when the electrons in the material return to their lowermost energy level or ground state. The semiconductors in LEDs can be one of many different materials (e.g. gallium arsenide, silicon, etc), each of which release their own particular wavelengths of light (i.e. infrared, visible, or ultraviolet) when a suitable voltage excites electrons up energy levels and back down to release energy in the form of light. Click here for a table of semiconductors and their respective photons released.
Interestingly enough, this method of producing light is highly efficient with energy, as opposed to standard light bulbs. Standard light bulbs produce light through "blackbody radiation." Essentially, by running a big enough current through a light bulb, the filament gets hot enough to emit light. It's the exact same phenomena when putting a piece of metal in fire until it glows. However, this method of lighting is very inefficient because energy is lost as heat and other wavelengths of light along its emission spectrum. On the other hand, LEDs will produce light using a smaller current to excite the material and emit light as a single wavelength, rather than a wide spectrum, that is particular to each material. In other words, LEDs emit light without wasting energy in releasing heat or other unnecessary wavelengths.
Now, if each LED emits a single wavelength of light, or color, then how do the bulbs in flow art props create just about every color imaginable? The answer is RGB - red, green, and blue. By placing a red, green, and blue LED in each bulb, each color can be blended together at different intensities to create any color. This phenomena of blending is considered Additive color mixing - the mixing of light. It comes to no surprise that Shuji Nakamura's discover of the highly sought blue led was crucial in developing colorful bulbs. On a more technical level, the RGB bulb is controlled via pulse width modulation (PWM) in adjusting the intensities of each LED.² PWM essentially alters the frequency at which LEDs rapidly pulse on and off in order to dim or brighten the color of each light.³ To add further, PWM also underlies visual effects like strobe in flow art props, whereby the LEDs are turned on for a duration of time (i.e. the milliseconds range) and turned on for a similar time sequence.²
Significant Uses
The small profile and high efficiency of LEDs make it extremely useful for not only flow arts equipment, but also sustainable lighting, communication, and vision-based devices. Although LEDs are expensive for lighting, they will consume less energy input for the same light output and also last significantly longer than most other lighting equipment. Additionally, infrared LEDs have been used for a long time in tv remotes to transmit signals to a platform. LEDs have also stepped into the territory of LED-based displays like TVs, phones, and other day to day electronics.
Advantages of LEDs
Disadvantages of LEDs
LED has become increasingly important the past few years due to its many implications. One significant use is in lighting up some of the flow art props detailed in the website. Granted flow artists can give nighttime performances with fire, it is usually not ideal for beginners or overall safety. Rather, LEDs are preferred because they accentuate an artist's movements and also his or her creative style given the spectrum of customizable colors, effects, and patterns. But to end this argument on just flow arts would be foolish, since LEDs are in our everyday life.
What are LEDs?
Light-emitting diodes (LEDs) consist of a semiconductor material that releases photons, or light particles, when the electrons in the material return to their lowermost energy level or ground state. The semiconductors in LEDs can be one of many different materials (e.g. gallium arsenide, silicon, etc), each of which release their own particular wavelengths of light (i.e. infrared, visible, or ultraviolet) when a suitable voltage excites electrons up energy levels and back down to release energy in the form of light. Click here for a table of semiconductors and their respective photons released.
Interestingly enough, this method of producing light is highly efficient with energy, as opposed to standard light bulbs. Standard light bulbs produce light through "blackbody radiation." Essentially, by running a big enough current through a light bulb, the filament gets hot enough to emit light. It's the exact same phenomena when putting a piece of metal in fire until it glows. However, this method of lighting is very inefficient because energy is lost as heat and other wavelengths of light along its emission spectrum. On the other hand, LEDs will produce light using a smaller current to excite the material and emit light as a single wavelength, rather than a wide spectrum, that is particular to each material. In other words, LEDs emit light without wasting energy in releasing heat or other unnecessary wavelengths.
Now, if each LED emits a single wavelength of light, or color, then how do the bulbs in flow art props create just about every color imaginable? The answer is RGB - red, green, and blue. By placing a red, green, and blue LED in each bulb, each color can be blended together at different intensities to create any color. This phenomena of blending is considered Additive color mixing - the mixing of light. It comes to no surprise that Shuji Nakamura's discover of the highly sought blue led was crucial in developing colorful bulbs. On a more technical level, the RGB bulb is controlled via pulse width modulation (PWM) in adjusting the intensities of each LED.² PWM essentially alters the frequency at which LEDs rapidly pulse on and off in order to dim or brighten the color of each light.³ To add further, PWM also underlies visual effects like strobe in flow art props, whereby the LEDs are turned on for a duration of time (i.e. the milliseconds range) and turned on for a similar time sequence.²
Significant Uses
The small profile and high efficiency of LEDs make it extremely useful for not only flow arts equipment, but also sustainable lighting, communication, and vision-based devices. Although LEDs are expensive for lighting, they will consume less energy input for the same light output and also last significantly longer than most other lighting equipment. Additionally, infrared LEDs have been used for a long time in tv remotes to transmit signals to a platform. LEDs have also stepped into the territory of LED-based displays like TVs, phones, and other day to day electronics.
Advantages of LEDs
- Highly Efficient: minimal energy input for desired lighting
- Color: can emit any color without the use of filters
- Size: can be as small as 2 square millimeters
- Refresh Rate: can be turned on or off in the microsecond range, without any delays
- Dimming: brightness can easily be dimmed with PWM
- Long Lifetime: around 35,000 to 50,000 hours of useful life
- Durable: difficult to damage and shock-resistant
Disadvantages of LEDs
- High Initial Price: cost of components are more expensive than other light solutions
- Temperature Dependence: performance largely depends on working in cool environment
- Voltage Sensitivity: voltage must be at a consistently narrow range so that LED is both on and not subject to shorter lifetimes
- Area Light Source: difficult to get a spherical distribution of light like standard light bulbs unless special optics are used
- Insects: much more attractive to insects than other light sources, so possibility of disrupting food webs
Interactive RGB Bulb Simulator⁴
Check out this web app for a closer look at Additive color blending, an important feature in RGB LEDs to create color.
Works Cited
¹ "Light-Emitting Diode." Wikipedia. 1 Aug. 2001. Last Modified: 10 Sep. 2015. Web. 10 Sep. 2015. <https://en.wikipedia.org/wiki/Light-emitting_diode>.
² Fallon, Jarrad. Owner of LEDgloves.com and designer of Aurora microlight chips. Interview through Facebook. 26 Aug. 2015.
³ Schiffer, Nick. Majoring in Electrical Engineering. Interview in person. 3 Sep. 2015.
⁴ Gruneich, Bryce; et. al. "Color Vision." PhET. Web. 10 Sep. 2015. <https://phet.colorado.edu/en/simulation/color-vision>.
² Fallon, Jarrad. Owner of LEDgloves.com and designer of Aurora microlight chips. Interview through Facebook. 26 Aug. 2015.
³ Schiffer, Nick. Majoring in Electrical Engineering. Interview in person. 3 Sep. 2015.
⁴ Gruneich, Bryce; et. al. "Color Vision." PhET. Web. 10 Sep. 2015. <https://phet.colorado.edu/en/simulation/color-vision>.