Blue light flooded the largest stadium in the United States, which was filled with tens of thousands of raucous American Football fans. People in the stands held their mobile devices aloft, producing a sea of star-like specks in the crowd.
This is our group! A video played on the enormous screen as cheers erupted in response.
The 16th of September marked the introduction of a new visual entertainment system at Michigan Stadium, which enhanced the atmosphere. Colored sequences of blinking, sweeping lights are used to commemorate touchdowns and to accompany music.
The colors of the University of Michigan team are yellow or “maize” and blue. The light display was synchronized.
Jake Stocker, director of game presentation and spectator experience at the University of Michigan, asserts, “It has a significant impact on the stadium experience.”
“One more exciting element of coming to a football game that you’re not getting sitting at home on your couch.”
At Michigan Stadium, as in many other stadiums, light-emitting diodes (LEDs) provide the light display.
However, not too long ago, blue LEDs powerful enough to illumine the third-largest stadium in the world would have been considered ludicrously advanced. In the 1990s, bright LEDs that emit blue light were first developed. Later, the inventors of the technology were awarded the Nobel Prize.
According to researchers, LEDs could become even more affordable and energy-efficient in the future. From outdoor illumination to virtual reality headsets, they could revolutionize everything.
Entertainment lighting systems with red (R), green (G), and blue-emitting (B) LED units or luminaires produce the various colors at Michigan Stadium, according to Brad Schlesselman, senior research engineer at Musco Lighting, which supplied the technology. By modulating the intensities of red, green, and blue, RGB systems can actually produce a vast spectrum of colors.
“It’s getting down to even the high school level where there’s a demand for the colour-changing and theatrical stuff that we’re seeing in Michigan,” states Mr. Schlesselman.
In addition, municipalities and cities in the United States are installing LED lighting on local landmarks, such as water towers, in order to illuminate the structures in different hues for special events or occasions. For October, which is Breast Cancer Awareness Month, the color pink is appropriate.
The Las Vegas Sphere, which opened last month, features arguably the most impressive use of LEDs. Millions of LEDs can convert the exterior into virtually any pattern or image imaginable and illuminate the interior’s enormous screens.
In the 1970s and 1980s, however, LEDs were considered ineffective. Paul Scheidt, senior product marketing manager at Cree LED, a major manufacturer of the devices, explains, “At the time, it was thought that this tiny toy light would be useless.” These costly and weakly emitting light sources were suitable for a red indicator light or an infrared TV remote, but not much else.
Engineers were able to produce LEDs that emitted significantly more photons, or light, than in the past. LEDs emit light when electrons, negatively charged particles, within the device transition from a higher to a reduced energy state. This procedure releases light-based energy. You can adjust the size of the drop (known as the bandgap) and the wavelength, or color, of the light emitted by using various materials.
Gallium nitride, the essential component for the blue hue, was challenging to produce without flaws. But blue is a powerful, very high-energy color (with a large bandgap), so blue LEDs can be used as the foundation for all other colors in some RGB OLED TV displays, for instance – the red and green tints would initially be illuminated by blue LEDs.
Typically, blue LEDs are also the source of white light. Using materials known as phosphors, the blue light is simply adjusted.
However, entirely new LED technology is on the horizon, as scientists believe it could be even more efficient.
Dan Congreve, Stanford University, Republican
Dan Congreve and his collaborators at Stanford University are constructing LEDs from perovskite crystals, a common component of solar cells. Perovskites are inexpensive and simple to manufacture. According to Dr. Congreve, they are “tunable” to the desired color and could be blended with a solution and painted onto surfaces as light-emitting layers.
Keeping perovskite LEDs stable is difficult, however. They continue to shatter.
Mr. Congreve states, “We turn them up and measure them, and they’re dead pretty quickly.” He adds that he hopes this issue can be resolved. Since their initial experiments, he and his associates have improved the stability.
According to John Buckeridge, a materials physicist at University College London, perovskite LEDs could be used in a broad range of devices if these obstacles can be overcome.
Separately, researchers in Japan have developed a blue LED that can be fueled by a single AA battery delivering 1.47 volts. Typically, a minimum of 4 volts is required. “That’s impressive as an engineering feat,” says Dr. Congreve, who was not personally involved with the task.
The system employs clever physics to increase photon production. When power is applied to a conventional LED, the internal materials attain excited states that, three-quarters of the time, do not actually emit light. The Japanese team was able to induce these energized states to combine and produce light while initially requiring less energy. In September, they published their work in a journal.
Keith Strickland, CEO of Plessey Semiconductors, a British company collaborating with Meta on such devices, explains that for technologies such as virtual reality and augmented reality, extremely bright LEDs are required to see images distinctly.
But current OLED displays aren’t bright enough, so the company is developing micro LEDs that are substantially smaller than 20 microns – that’s less than a third of the width of a human hair.
Dr. Strickland notes that at this microscopic scale, it is the color red that poses the greatest difficulty. Red micro LEDs are more susceptible to edge inefficiency than other micro LEDs. Due to the diminutive size of the device, its edge has an exaggerated effect, making these issues more apparent.
LEDs are rapidly gaining popularity, but their technological development is not yet complete. According to Dr. Congreve, “There’s still room to grow” – and presumably shine.
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