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can you tell the latest advancement in led technologies?

Iron

Anyone listening who has a solution for using LEDs for indoor plant growth (see www.atlanticlivingwalls.ca). I am looking for recommendations on what type and brand of LED's I can use to provide the proper light spectrum for healthy plant growth.
The limitations I face is that the lights cannot be up near the plants. They must be effective from a distance of ten (10') feet or more.....

I build interior living walls (vertical gardens) with living plants (mostly house plants that require medium to low light levels). We would like to use LED's.  However, the led's I have seen so far need to be within a few inches of the plants. Is there a high lumen, full spectrum led flood light that you can recommend for healthy indoor plant growth?

Thanks guys!

Are there other LED broadcasts that you have on a regular basis?

Could participants receive an email link to the audio archive when it is available? Thank you!

Gold

Hey carol, keep up the good work ... I'm just a simple guy from Canada, trying to do something interesting with light and power ;-)

Thank you Alex and Carol. This was a very informative and interactive show. The Databeans 2011 LED Market Research Report will be available next week, anyone interested feel free to email me any questions about the market. Thanks!    brice@databeans.net

Iron

thanks Carol and Alexander !

puneetgupta: it's on a closed group on LinkedIn

http://www.linkedin.com/groupItem?view=&gid=1858213&type=member&item=12595524&qid=644a907d-2f11-46a6-8e55-b0f6c706790d&trk=group_most_popular-mc-rr-ttl&goback=.con.gmp_1858213


Yes,thanks for a terrific program.

Blogger

Enjoyed it! Good luck designing!

Blogger

Suomen, thanks for jumping in and clarifying CCT and so forth.  Yes, light is fascinating!

Blogger

Carol, thanks so much for your participation. Listeners who want to hear our chat again can access an archive of the audio stream. The instant chat answers will also remain posted up.

Blogger

We also have a book out for further questions. You can "look inside" to see the contents on Amazon.

Practical Lighting Design with LEDs  by Wiley-IEEE Press

Blogger

Carol, when discussing CRI, and 'dimmer', with wide-spectrum lighting, you've touched on an interesting point of photometric 'brightness', compared to total visible light output power ...

Yes, I was talking about backlighting applications.

I meant controlling the soldering profile during assembly for more sensitive LEDs.

For reference, here are some standards to be aware of.

IES Illuminating Engineering Society
LM79 Approved Method: Electrical and Photometric Measurements of Solid-State Lighting Products
How to test luminaires for light output.
Time for thermal stabilization.
Must use integrating sphere, not calculated lumens based on spot lux measurements, etc. 

LM80 Approved Method: Measuring Lumen Maintenance of LED Light Sources
How manufacturers should establish LED lifetime

UL 8750 LED Equipment for use in Lighting Products
UL 1993, Standard for Safety of Self-Ballasted Lamps and Lamp Adapters

Blogger

LEDs are wide spectrum compared to fluorescents. They lack the reds compared to incandescents. Reds are also inefficient to create, since your eye is not as sensitive to it. There are special LEDs with 90+ CRI. But they are dimmer.  

Some companies add in red or amber LEDs to compensate.

People are also looking into using quantum dots instead of phosphors to improve color.

Blogger

I have not worked with light guide films. I assume you are talking about backlighting applications. What do you mean about solder temperature?

 

Blogger

Is there an a way to create wide spectrum light from LEDs like you can with incandescents - possibly with phosphor formulatios?

Gold

puneetgupta - alignment, especially with thin light-guides, is critical to both efficiency and colour

Maybe in the future, you would have more personal lighting. If you like cooler white, that is easy with LEDs but very hard with incandescents.

 

If you want cooler light in the morning to wake you up, or yellower warmer light in the evening, that is possible with LEDs.

Blogger

Since no one else is asking more questions, Ill post some more:

Are there are tips when desgning for light guide films with top as well as side firing LEDs? How critical does alignment/solder temperature become? Also how critical is it to keep the light guide surface pristine and prevent any fingerprints/dust/etc?

About AC LEDs. The concept is great. But the two manufacturers that I know of that make them do not have the most efficacious LEDs. Dimming is probably not compatible. The light output would vary when the line voltage varies. You would also need to add protection circuit for surges.

AC LEDs are patent protected. Maybe in the future, once the other improvements are exhausted, they will become more popular.

Blogger

Thanks Carol!

suomen_karhu: Can you send me the link to the discussion?

puneetgupta - there's also a long discussion of this issue on LinkedIn

People complain about "the color", but I like the bluish light. I think it makes things look clearer and more like sunlight than the yellowish ones. So I hope there are lamp choices, not "one fits all".

Silver

Variability of color is a limit of the particular equipment. There are spectroradiometers that measure color precisely. Just a question of if you want to pay for it. 

To borrow from integrating sphere practices, you could have a few "standard" lights, of blue LED, incandescent, to do a quick calibration across the equipment. Just keep track of the usage of the "standards" so that when they start aging, you replace them and transfer the calibration to the new "standard".

Blogger

Once the industry moves beyond retrofiting products with LEDs as a direct replacement for fluorescent and incandescent, what's are some of the next advancements/benefits LEDs can offer?

Blogger

I see a big market for new lighting fixtures rather than replacing incandescents with their omni patterns and highly attenuating lampshades. Put the light where you want it.

Silver

Color binning can be an issue if your specs are extreme. Generally, though, binning is not as bad as it might appear from the datasheet. Each reel of LEDs tend to be closer in color than the size of the bin indicates.

Blogger

How can one account for the variability in color measurements in between different measurement equipment? It is really hard to calibrate color measurements between different colorimeter manufacturers in general.

The audio portion is over. Carol is answering questions now on the chat here

Blogger

Carol's comment about using LEDs in ways that make use of the new possibilities offered by LEDs is right on the mark ... economics seem to be driving manufacturers to develop retrofit products for fluorescent and incandescent, missing out on the best that LEDs can offer

Hello, where do you see led lighting go for growing vegetation? I presume the color of the led will effect how efficient the replacement would be correct?

Iron

@junyang25: Some firewalls block our streaming audio signal; yes, this will be archoved if you want to try and listen from home

How cost effective will conductive polymers be over the next two years for OLED applications?

Platinum

I lost the sound also. Is Carol still on the line?

Iron

Driver lifetime is a big concern. It can be engineered to your specs, though. Get a good power supply designer. Then can do an analysis on the stress of each component based on current, temperatures, ratings, and come up with a life time estimate or change to more expensive components to increase lifetime.

 

Blogger

Junyang25, yes we will post an archive of the audio

Blogger

Cannot get the radio, even changed computer.

Can I listen to its record later somewhere?

 

Iron

Please re-post questions for Carol Lenk that weren't able to get to during the live audio

questions for carol?

 

Blogger

good show; kept it moving with good content.

Iron

CCT is a way of relating colour that does not lie on the Planckian locus, to the 'closest' colour temperature on the Planckian (Black Body) line ...

 

I agree with Doug. This is an interesting show.

Blogger

LED's in the medical market grew by about 23% between 2010 and 2011.

 

Iron

If LEDs have a long lifetime, but drivers typically have a shorter lifetime, what kind of considerations does that have on a design in terms of matching the two to minimize down time and rework?

Blogger

Good atuff Carol and Alex.

Platinum

That's also where conductive polymers become interesting. Power for indoor displays can be picked up from overhead fluorescent lights.

Platinum

since LEDs are almost never connected directly to a line source, the driver takes out most voltage fluctuations

 

I've heard the voltage fluctuation negatively affects LEDs. Is this an issue?

Blogger

Are there any tips on how one can account for different LED illuminance/color bins in a design?

rapidly coming to cars and trucks, even OEM truck headlights from Dialight, as well as all the headlamps in Audi, and others

 

how does a light dimmer affect the high-brightness LEDs???

 

Iron

Databeans projects that LEDs will remain the largest and fastest growing optoelectronics product market in 2011 with $7.9 billion in global sales and a CAGR of 20 percent over the forecasted period. Meanwhile, total unit shipments will reach 95.5 billion in 2011 with a CAGR of 23 percent over the period. Its only a matter of time before they take over the market, environmental will definitely be the leader in this push.

Iron

Do OLEDS provide advantages over traditional LEDs?

Blogger

Sorry the constant current source is using on two transistors and a few resistors

Iron

I use a constant current power source. Isn't this cheaper and simpler than a dedicated IC from TI or whatever?

Iron

I visited the Phillips Design Center in the Netherlands last year. They feel that LEDs will take over most lighting applications. Is this pie in the sky?

Platinum

Chuck raises a good point. I see increased use of LEDs for accent applications in automotive interiors. When will they start doing some heavy lifting?

Platinum

Are gently driven AC/Leds superior to a  lumeniareS using DC - LEDs DRIVEN at at 700 mA ?

 

Iron

Why are some of the key ways to handle the heat dissipation issue?

Blogger

what can you tell about the innumerable lighting standards that designers need to be cognizant of?

Iron

Great questions.. please keep 'em coming!

Please refresh your browser if you're not getting the audio player above this box

Is it true that LED will out live it's components?

Iron

I see that LEDs are making headway in automotive interiors. What's it going to take to get LEDs into more headlights? Lower costs?

Blogger

What's the status of conductive polymers in OLED applications, e.g. Plextronics applications?

Platinum

What are some of the emerging, more popular applications for LEDs?

Blogger

Is it true that LED fixtures will freeze over in an outside atmosphere???

Iron

Please post your questions for Carol Lenk so that Alex Wolfe can ask them during the live audio

Hi Alex and everyone out there. I'll be back to chat after the talk.

 

Blogger

Thanks for joining us this DN Radio segment

zWelcome, early birds. FYI, the streaming audio player for the live portion of the show -- my chat with Carol Lenk -- will appear on screen at 2pm eastern.

Blogger

What do you see as the near-term potential for OLED technology?

Platinum


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