LED explained by Dan Blitzer

An in-depth explanation of LED technology, its advantages, challenges, and applications by Dan Blitzer from Signify.

Key Takeaways

LED technology is revolutionizing lighting with superior efficiency and longevity.
Proper heat management is essential to maintain LED performance.
LEDs provide versatile lighting options and are environmentally friendly.
Initial costs and dimming challenges remain barriers but are outweighed by benefits.
LEDs are increasingly adopted in commercial and institutional applications.

What the video covers

LEDs are the first 21st-century lighting technology replacing older incandescent lamps.
LEDs emit light through semiconductors and can produce various colors but require phosphor to create white light.
LED arrays and drivers convert normal electrical supply to low voltage direct current for operation.
Optics control LED light beams precisely due to the small size of the LED source.
Heat management is crucial for LED performance and longevity, using heat sinks or advanced cooling designs.
LEDs are highly efficient, lasting 10-20 times longer than incandescent bulbs and more efficient than fluorescent or HID lights.
LEDs operate well in cold environments, dim easily, and are environmentally friendly with no mercury or UV/IR emissions.
Challenges include sensitivity to high heat, dimming electronics complexity, and initial cost for high brightness setups.
LEDs are widely used in refrigerated displays, colored lighting, retail, outdoor lighting, and are considered for offices and schools.
LED lighting offers versatile light experiences with warm, cool, changing colors, and various beam shapes.

Chapters

Why can't LEDs produce white light by themselves?

LEDs emit specific colors like blue, green, or red, but to produce white light, a blue LED is combined with a phosphor material that converts some of the blue light to white.

What is the role of a driver in LED lighting?

A driver converts normal electrical supply (120 or 277 volts AC) into the low voltage direct current needed to power LEDs effectively.

Why is heat management important for LEDs?

LEDs are vulnerable to heat; without proper cooling through heat sinks or advanced designs, their light output drops significantly and their lifespan is reduced.

Full Transcript — Download SRT & Markdown

Speaker A

Welcome to the fascinating and rapidly growing world of LEDs – Light Emitting Diodes. Our first 21st-century lighting technology - LEDs, and here’s an example of one design to replace incandescent lamps, are rapidly replacing older 20th-century technologies

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in many commercial applications. Inside this LED replacement lamp is one of these -- actually several of these -- small-scale light-emitting diodes.

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It is similar to the semiconductor that is inside your cell phone and your computer, except that these semiconductors emit light when electricity passes through them.

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Depending on how they are made up, the light can be blue, various colors, green, amber, orange, or red.

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What it can’t be by itself is white. To make an LED white, you have to convert one of the other colors -- in this case blue -- to white, as we do here.

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Using a material called phosphor, we convert some of that blue light to white. Here’s a large-scale example.

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White light begins as blue light; the phosphor converts it to white. The LEDs are typically grouped together in an array of several LEDs to provide a sufficient quantity of light to fulfill our requirements.

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However, they can operate on normal electrical supply at 120 or 277 volts. They need a low voltage supply on direct current, such as you would receive from a battery.

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To convert, we use a device called a driver. Here’s one on the light fixture, here’s one built into a replacement lamp, and here’s a really tiny one built into this size replacement lamp.

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In addition to the LED array and the driver, there are also optics to control the light into the beam that we want.

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Due to the small size of the LED source, we can control it very precisely.

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See the light on the wall; watch what happens when we put a lens over it.

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The optic transforms it into a tight spot. Finally, LEDs are vulnerable to heat. If we don’t remove some of that heat, the output drops off dramatically, and the LED ceases to be useful.

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So we can use a cast heat sink whose mass will help us evacuate the heat from inside, which will harm the LEDs.

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Or we can use more sophisticated designs such that we can use multiple surfaces to help air currents remove the heat.

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In either way, we need to cool the LEDs or they won’t long be useful to us.

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LEDs offer several important advantages, the most significant of which is their efficiency. They are 4-5 times as efficient as incandescent sources, a little bit more efficient than fluorescent or HID lighting, and the light sources last a long time, 10-20 times as long as incandescent

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and slightly longer than fluorescent or HID lighting. Unlike fluorescent sources, LED likes to operate in the cold, and unlike HID sources, it dims easily.

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LEDs are also environmentally friendly. They emit no ultraviolet or infrared radiation, and they contain no mercury.

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There are, however, several challenges to using LED lighting. First, LED sources don’t like to operate in high heat environments.

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Their electronics present some difficulties when dimming, and it can be expensive on an initial basis to get enough of them together to be useful in a high brightness environment.

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Today, LEDs have already become the predominant light source in such applications as refrigerated display cases and colored lighting effects.

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They’re rapidly making inroads in retail display and outdoor lighting and are being seriously considered for such other commercial and institutional applications as offices and schools.

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But perhaps what’s most exciting is what LED lighting can do to the way we experience light.

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It can make light that is warm, that is cool, that changes back and forth, that can make interesting colored lighting effects; beams can be very compact or very diffused.

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The horizons are completely open.

Topics:LEDLight Emitting DiodeLED lightingphosphorheat sinklighting efficiencycommercial lightingSignifyLED driverlighting technology

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