Filament LED

[JohnR66]

If you ever made an array of 5mm LEDs on a perfboard you have seen how warm they can get at 20ma. These things so tightly spaced can still get quite warm. I can't say how warm, but they probably could last if quality parts were used. If they used the Fade-in-a-week crap dies like I've seen in so many 5mm LEDs and strip LEDs, well don't expect much.

Lightdoctor. If you have actually tried these LED bulbs, I'd be curious of their failure mode.

Indeed I pick on crap products. I have tested lots of various 5mm LEDs that don't last a week. Traffic signal LED lamps with sections out. Commercial lamp installations with several emitters out. Chinese COB LEDs with strips in the array that fail. Lots of store display products where the LEDs have faded severely.

Think of the consumers that buy this crap and have it fail on them. They are reluctant to try new LED products and will badmouth it. "I tried that LED stuff and it was a waste of money. Pure junk." Discouraging for people like me who want to see LEDs succeed.

 

[Lightdoctor]

JohnR66,

I have not bought the lamp in question, but I have bought in the past from the said vendors. I happen to work in energy conservation, and like you, have seen many LED bulbs, traffic signals, street lights (cobraheads, shoeboxes etc.) fail. Where were the parts sourced from? China. Why? Greed, pure and simple. There are superior products from the US, and the EU, that blow away the far east crap.

SemiMan,

Do you work in the industry, or is this a hobby? Why are you so defensive? Something to hide? You've been to the automotive board and heard about the less than stellar products that come from over there. If you think the LED filament bulb is so great, link up more information and try to change my mind instead of saying people who don't agree with you are stupid.

 

[SemiMan]

Not at all defensive and do work in the industry.

I will speak out against ignorant comments. For one a reminder that most Philips bulbs are made in China ... Yet a comment made that because Cree and Philips have not done this that it can't be good. That is a foolish comment.

5mm LEDs fail mainly due to the epoxy phosphor interface causing the epoxy to yellow and haze, not failure of the underlying blue die. A lot of others fail due to overdriving.

Remember when people used to make fun of Made in Japan?

No one has even tried to do a thermal analysis. LEDs in silicone at 100c (or higher) can last a long time and at 100c+ radiative loss is not insubstantial and you have the full cylinder for surface area.

FYI , no ripple is easy when power factor is not a concern.

 

[made in china]

JohnR66,

I have not bought the lamp in question, but I have bought in the past from the said vendors. I happen to work in energy conservation, and like you, have seen many LED bulbs, traffic signals, street lights (cobraheads, shoeboxes etc.) fail. Where were the parts sourced from? China. Why? Greed, pure and simple. There are superior products from the US, and the EU, that blow away the far east crap.

SemiMan,

Do you work in the industry, or is this a hobby? Why are you so defensive? Something to hide? You've been to the automotive board and heard about the less than stellar products that come from over there. If you think the LED filament bulb is so great, link up more information and try to change my mind instead of saying people who don't agree with you are stupid.

I work in the transportation industry now. I used to work in the semiconductor industries in the USA, Korea and China. Currently I have a side business engineering and manufacturing custom PCBs, power trays, harnesses, etc. A while back I was at the maintenance depot of our European made street car system. They had the motor drivers on a bench. These are made in Germany. I popped a cover on one, look at the PCB components and I immediately recognized a relay I have used many times before on interlock PCBs. I was floored to see that the Omron relay was made in Germany! The only kind I have been able to source are Omron from China. Same exact relay. I started looking around the driver assembly and realized that I couldn't find any parts made in China. Mostly European, Korean and a few USA and Japan components. It was pretty obvious that the manufacturer of these drivers took reliability seriously. Surprising me was the fact that you can still find stuff that's not "Made in China", WOW!

Not at all defensive and do work in the industry.

I will speak out against ignorant comments. For one a reminder that most Philips bulbs are made in China ... Yet a comment made that because Cree and Philips have not done this that it can't be good. That is a foolish comment.

5mm LEDs fail mainly due to the epoxy phosphor interface causing the epoxy to yellow and haze, not failure of the underlying blue die. A lot of others fail due to overdriving.

Remember when people used to make fun of Made in Japan?

No one has even tried to do a thermal analysis. LEDs in silicone at 100c (or higher) can last a long time and at 100c+ radiative loss is not insubstantial and you have the full cylinder for surface area.

FYI , no ripple is easy when power factor is not a concern.

Many people get all excited about flashy new products and tech, most of which comes from China. They want to believe the hype and buy into it. But soon they end up with a pile of junk at home, in the office, etc. All this Chinese made stuff that fizzled out because it was made cheaply. But fortunately for the Chinese, we westerners are easily distracted with our collective consumeristic ADD. We're being conditioned to accept junk. I think both of you know that the reason behind the bad rap Made in China gets is complicated, and not as simple as where it is made. Some manufacturers do have good success with factories in China. Most don't, IMO.

Semiman, China is NOT Japan. Officially, China is our adversary. Japan is an ally. China has vast, nearly endless cheap labor, and can decimate western industry for many more decades than Japan could have. I loath when people say "we used to say the same about Japan". But, whatever, I'm stuck riding this sinking ship down with everyone else.

OTOH, I do really like these light bulbs. If they could make a dimmable version, that'd be great.

 

[SemiMan]

Made in China simply discounting everything made in China as crap was the same tactic the automotive industry made with Japan who may be military allies if you could say that but I don't think care too much about US success. The American automotive industry is still trying to recover from that arrogance.

China is not decimating Western industry we are pretty good at doing that all on our own whether it is greed of business or that of consumers.

 

[JohnR66]

I agree that the products manufactured in China are not all of poor quality. There are quality products but they command a higher price. Cree does (or did) make some of their LEDs in China. I do take issue with the large amount of counterfeit products that flow out of the country.

I'm well aware of the 5mm LED fading issue due to low grade epoxy. It is also because the die used is very small and degrade from the current flow.

 

[henningdalgaard]

Any more news on the durability of these china filament bulbs? Do they leak helium after a while? Do they fail or change after 2k hours?

 

[degarb]

I am waiting for the retro-nostalgic curly led filament bulb.

 

[PhotonWrangler]

I am waiting for the retro-nostalgic curly led filament bulb.

This might be achievable with OLEDs on flexible substrates.

 

[tino_ale]

What's new on those filament LED bulbs ? Any feedback on their life span ?

 

[night.hoodie]

What's new on those filament LED bulbs ? Any feedback on their life span ?

http://greenbuildingadvisor.com/blogs/dept/guest-blogs/led-filament-bulbs
via /.

 

[Anders Hoveland]

I wonder if these LED filament designs can really achieve the high enough light outputs necessary to replace a 100 Watt incandescent bulb, for example.
It is more difficult to dissipate heat directly to air without some sort of heat sink.

My guess is these filament bulbs are mostly decorative.

 

[angerdan]

One regular filament-stick deliver around 105lm. There are currently lamps with 12 sticks and 800lm.
E27 B22 4.6w 8.2w LED Filament Lamps Bright lights High Power SMD bulbs | eBay

 

[night.hoodie]

I didn't RTFA, but the /. summary claims something about these things not needing heatsinks. So there should be some interest in these forums for not only how or why it is achieving the quality of light that is claimed, but also why its not throwing off more heat. /. has gone down hill, and its rarer to see some solid dialogue in the comments, someone pointing out the tell tale sighs of BS or perpetual motion machines, or perfect efficiency. So as soon as I saw it, searched here, found this thread, and posted link. I want to know what sorcery this is, without having to do any real work. I am qualified to request and expect something for nothing because I am American. TIA.

 

[PhotonWrangler]

40 watt 4-strip LED "filament" bulb, thermal images. Ambient temp was 72 degrees, bulb operating base-up in an open fixture -

After 30 seconds the temperature of the hottest spot was 84 degrees.

LED_filament_30seconds_84_degrees

After about three minutes, the temperature stabilized at 93 degrees -
LED_filament_5mins_93degrees

 

[CoveAxe]

My guess is that the inside of the bulb is pressurized with air or nitrogen. This will conduct heat much better to the outside surface, which has a much higher heatsink area than normal LED bulbs.

The lack of sophisticated electronics on board also likely helps. If I remember right, the power factor on these bulbs are just horrible (like around 0.6 or lower). You can get rid of a lot of heat-generating components when you don't care about that kind of stuff.

 

[tino_ale]

Very interesting. I am certainly not an expert in thermal imaging but it looks like the heat is rather well spread in the bulb !

 

[SemiMan]

My guess is that the inside of the bulb is pressurized with air or nitrogen. This will conduct heat much better to the outside surface, which has a much higher heatsink area than normal LED bulbs.

The lack of sophisticated electronics on board also likely helps. If I remember right, the power factor on these bulbs are just horrible (like around 0.6 or lower). You can get rid of a lot of heat-generating components when you don't care about that kind of stuff.

Air only transmits heat if it moves. I do imagine that the design of the LEDs could create a bit of a chimney effect. I wonder if we will see that the LEDs at the top will degrade faster.

 

[SemiMan]

40 watt 4-strip LED "filament" bulb, thermal images. Ambient temp was 72 degrees, bulb operating base-up in an open fixture -

After 30 seconds the temperature of the hottest spot was 84 degrees.

LED_filament_30seconds_84_degrees

After about three minutes, the temperature stabilized at 93 degrees -
LED_filament_5mins_93degrees

If I am not mistaken, standard glass, as what would likely be in these bulbs, would not transmit any of the long wavelengths that would be representative of the filament itself, i.e. you cannot image the filament from outside the bulb in the IR. Any reading would likely be highly erroneous, so what you are doing is imaging the glass which due to the surface area would stabilize at a low temperature, but that is not at all indicative of the temperature of the filament inside which is insulated by a somewhat non moving insulating medium.

 

[PhotonWrangler]

If I am not mistaken, standard glass, as what would likely be in these bulbs, would not transmit any of the long wavelengths that would be representative of the filament itself, i.e. you cannot image the filament from outside the bulb in the IR. Any reading would likely be highly erroneous, so what you are doing is imaging the glass which due to the surface area would stabilize at a low temperature, but that is not at all indicative of the temperature of the filament inside which is insulated by a somewhat non moving insulating medium.

This did occur to me. The glass will block some of the longwave IR energy, however it will also gradually warm up to a temperature that gives us at least a comparative reference. I've tested conventional LED bulbs where the temperature of the hottest portion was usually the electronics in the base, which would reach into the 130s. Granted the base is designed to conduct heat to the outside, so the thermal path from the semiconductors is much better than the path from the filament LED to the glass wall.

Unfortunately I'm not willing to break the bulb open to image the LED filaments directly. Maybe ElectronUpdate has already done this? He has the same thermal imager that I do.