One Last Advantage of LEDs

LEDs will ultimately provide higher efficiency than other commonplace lighting sources. They start instantly instead of needing to warm up. They run cooler. They last longer…

Wait a minute—what does it mean when people say they last longer?

When incandescent, halogen or fluorescent bulbs fail, they become unable to produce light.

Properly mounted LEDs age more gracefully. Their intensity gradually diminishes with age and the colour they emit may shift. Their published useful lifespans do not indicate when they will go dark. Their lifespans are the number of operating hours that can be expected before they reach an agreed level of dimness by comparison with their brightness when they were new.

The useful life of LED lighting ends when its light output has dropped by 30% for general lighting, or 50% for decorative lighting, with not too much shift in the colour of the light.

If your LED light goes out, something else has probably gone wrong. Some examples:

  • Another component in the lighting unit may have died, such as the power converter that changes high voltage alternating current to low voltage direct current.
  • An electrical connection may have come loose.
  • The design of the lamp may have mounted the LEDs so the heat they generate is not pulled away well enough and they cook themselves.

Red, Green and Blue Cannot Always Provide the Whole Spectrum

I mentioned that combining red, green and blue (RGB) LEDs is a step in the right direction, but only when the light is shown into your eyes.

Take a look at the visible spectrum in Part 1 of this series of posts. See the size of the gap between red and green?

Your eyes and brain happen to be most fond of a colour midway between those two. Since LEDs emit a relatively pure colour, RGB light from LEDs misses that portion of the spectrum. Fortunately for makers of televisions and computer monitors, your brain is capable of mixing two colours that come into your eyes to perceive a colour in between, even though that colour isn’t actually being shown.

But when you use LEDs to illuminate objects that you want to see, that does not apply. When you look at an object, you see the light that is reflected by that object. If it is a blue object and you shine white light on it, only the blue light is reflected into your eyes, so you see the object as blue.

With RGB LED lighting, objects that are red or green or blue look fine. Objects with a colour between green and red on the spectrum look dull at best and may look almost black. RGB light does not shine the right colour on them for reflection.

Theatre lighting has begun to address this by adding amber LEDs. Theatres need to be able to vary the colour of lighting shone on the stage, and they need enough coverage of the visible spectrum for emphasis on specific moods or specific elements of the set. They can’t have yellowish items on the set look like mud to the audience.

Such LED lighting units are described as RGBA. Although RGBA is beginning to make its way into consumer goods, it is not yet at the level of quality and controllability available in theatre lighting.

As I mentioned on the home page, I have seen LED based lighting that blows away the currently available lighting in practically every regard. I watched a scientist sit down under one of the lab lights and exclaim that it was the first time in years that she had been able to read without special eyeglasses to compensate for a visual disorder she has.

Unfortunately, it’s still highly proprietary and the only person who can take it home is the inventor. But stick around. It will reach the market someday, and I will tell you when it does!

Click to read more…    Page 1    Page 2    Page 3

Further Discussion

We are at the awkward point where new technology is emerging rapidly, and you can find some really good new lighting available to buy. But a lot of junk is also out there in the marketplace. With any new technology, it takes a while before everybody comes up to speed about how to handle it.

When I find something I feel is worth mentioning, I post about it. Click here to see those posts.