Two consumer LED (light emitting diode) light bulbs from Philips. The high-efficiency “L-prize” bulb is on the right. Photo by Geoffrey A. Landis.
Solid-state lighting in the form of Light Emitting Diodes (LEDs) converts electrical energy into visible light with greater efficiency and less heat loss when compared to incandescent or fluorescent lights.
Above a certain current, however, LEDs become less efficient and convert less of their electrical energy into light. This is a condition known as “droop,” which makes the use of LEDs in high-power applications difficult.
The next generation of solid-state lighting may use laser diodes, which overcome some of the LEDs limitations by operating at higher power and optical intensities, but are about the same size.
As lasers are brighter than LEDs, they require fewer diodes for an equivalent light source, which makes the device cheaper and more compact.
“White” Light Sources
LEDs and laser diodes share one characteristic – they are monochromatic, or emit a single color of light. To create white light from either source, we use one of two methods.
- The first method combines the primary colors – red, green and blue – to create white light.
- The second method of creating white light uses either a blue or ultra-violet diode along with phosphors to “down convert” the higher frequency light into a range of lower frequencies. By blending phosphors in the right combination, we can get something that looks like “white” light.
Phosphor Driven White Solid-State Lighting
There are several complications affecting our ability to blend phosphors to get white light.
Firstly, as a diode’s color output can degrade with age or drift with temperature, it’s necessary to use complex optics and electronics to actively monitor and control color output.
LEDs can be coated with phosphors to generate white light, but the heat they generate can degrade phosphors over time.
As phosphor-coated LEDs generate visible light sources, we need optics to diffuse the light beam.
If we separate the phosphor from the LED, however, it overcomes these issues. Philips currently uses this “remote phosphor” design, which won the L Prize in 2011, a competition run by the US Department of Energy to encourage lighting manufacturers to develop high-quality, high-efficiency solid-state lighting products.
Click to Read Page Two: Laser Diodes for Remote Phosphor Design
Wow, that’s just great! I’m glad your looking forward to the future of light emitting technology. Laser diodes are definitely going to be taking the automotive lighting field into the future, and it’s already happening. As certain technical issues are perfected, we will see more and more laser diode-powered lights entering our technology sphere. I’m glad that you posted your eloquent comment to “decodedscience.org”, because it gives me hope that there are a few people in the United States that actually have an inert knowledge of how things actually work, without having to be taught in a classroom. Unlike most people, I absorb every bit of information that my five senses transmit to my brain, and I’m able to understand how things work and theorize how to improve upon nearly every area of science I come across.
My brain is somewhat freakish in that I can retain information for decades after being exposed to a particular technology only once. This prompts me to study a little bit of everything, but I lean toward studying the technological advantages of using cutting-edge technology commonly used in a specialized area of technology with the goal of implementing it into an entirely different type of application.
I actually qualified to be a guest on the quiz show “Jeopardy”, but due to the luck of the draw, I was not able to record any actual episodes. I was disappointed about Jeopardy, but I felt somewhat vindicated when I was featured in November 2017’s edition of Popular Science Magazine (in print) due to the sheer amount of random, yet often crucial information that I retain for long periods of time, and my knowledge of the way the world works is so vast that I often providing consulting for engineering firms that are stuck at a particular stage of development in certain projects.
I am in the process of funding an organization which will focus on new and far better ways of teaching young children and adults about all facets of the universe, and how we can put just about everything to work to better humanity.
i want to replace the led light with laser light.