# LEDs with filaments!



## Illum (Jan 13, 2009)

Japanese company Ushio Lighting came out with a 2500K Filament LED lamps for decoration/general lighting purposes...
At 0.6W per lamp they rated the output to be ~18lm...not too shabby but far from bright:duh2:









Chinese link: http://big5.nikkeibp.co.jp/china/news/elec/elec200901070126.html?ref=ML

Japanese Link: http://techon.nikkeibp.co.jp/article/NEWS/20090105/163584/

Up to now the LEDs we have seen only emit light in one direction, the LEDs used in these lamps emit light in all directions, I wonder how they managed with heatsinking. :thinking:


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## LukeA (Jan 13, 2009)

Technologically it's an interesting achievement but it's not too practical. As you hinted, heatsinking will be terrible. That's why the flux is so low.


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## Sgt. LED (Jan 13, 2009)

COOL!


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## Kiessling (Jan 13, 2009)

That's actually very useful for quite a number of "design" lamps that need a pretty bulb. One less argument to avoid LED bulbs, sigh.


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## jtr1962 (Jan 13, 2009)

My first thought is WHY? LED completely changes the lighting paradigm. It shouldn't seek to imitate incandescent lamps. Indeed, I'm hoping the whole concept of screw-base lamps gets obsoleted eventually. Anyway, at the low output of 18 lumens these really aren't a practical lighting solution. They're more like an accent light.


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## LLCoolBeans (Jan 13, 2009)

jtr1962 said:


> Anyway, at the low output of 18 lumens these really aren't a practical lighting solution. They're more like an accent light.



I think that's exactly what they are intended to be, accent lights. It's at least somewhat practical for that application.


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## spencer (Jan 13, 2009)

The advantage I see to these is that they emit light 360 degrees. To achieve this with regular LED's you would need many pointing in different directions. I like it.


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## EricB (Jan 14, 2009)

Wow! How do they do that? Aren't LED dies like little points? It seems the whole length is lit. 


jtr1962 said:


> My first thought is WHY? LED completely changes the lighting paradigm. It shouldn't seek to imitate incandescent lamps. Indeed, I'm hoping the whole concept of screw-base lamps gets obsoleted eventually. Anyway, at the low output of 18 lumens these really aren't a practical lighting solution. They're more like an accent light.


 That would also be good for chandeliers, and to better emulate faceted, frosted or opaque Christmas lighting (to spread the light around better so it's not concentrated toward the base). I wonder if those can be made rgb. And the higher color temperature whites would look interesting in a filament.

LED's with filaments, LOL! When they first made the so-called "rice lights", I thought they were LED's, until I saw the little filaments. Then, there was a bulb with several small clear rice lights in it, and I thought they were realistic looking 2700K LED's, until I noticed they were filaments.


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## 2xTrinity (Jan 14, 2009)

> The advantage I see to these is that they emit light 360 degrees. To achieve this with regular LED's you would need many pointing in different directions. I like it.


In general I think the whole idea of emitting light in 360 degrees, then taking a lampshade and blocking out the vast majority of those angles completely stupid for general purpose lighting.

We should be moving AWAY from omnidrectional point sources, to fixtures that are inherently directional, and throw light where it's actually needed -- without wasting the vast majority of it in the process.

To take a design that is inherently both high efficiency and directional, and make it low efficiency and omnidirectional are a couple steps backward.

I Agree it's an interesting curiosity, as it relates to accent lights, but I agree with JTR in this case that I want to see fixtuers that actaully take advantage of LEDs' unique properties to make lighting fixtures that are better and more practical than what we've seen before on the incan and fluorescent front. To try to shoehorn LEDs into a role it was never designed for (similar to the whole concept of CFLs, but worse) IMO would be a shame. As unfortunately I suspect this will be the only option widely available on the market...


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## Kiessling (Jan 14, 2009)

Fortunately, we're not solely composed out of reason and what we "must" and "should" do. There's more. Like omnidirectional light sources. And filaments.


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## Illum (Jan 14, 2009)

heatsinking...refrigerator lamp anyone?


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## PhotonWrangler (Jan 14, 2009)

I don't get it. Looks like a coated filament to me. :thinking:


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## 65535 (Jan 16, 2009)

I imagine it is an unusual die design, where the die (which is just a semiconducting diode not anything special IIRC it's a pretty uniform material) and is simply formed into a long string shape (likely a long square cross sectioned rect. prism) then coated in a phosphor.

If my logic is right the only reason LED's are the way they are is that the dies are efficiently cut in squares and with the demand for heat sinking they must be mounted down.


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## purduephotog (Jan 16, 2009)

I can think of a really easy way to do this- it's called heat pipes.

Coat a heat pipe with resist, put the LED material down, put the phase change material in... and there ya go. heat goes into the pipe, evaporates, condenses at the top, runs back down. Closed circuit, heat moves away, massive surface area available for lighting.


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## Oznog (Jan 16, 2009)

My god.... the deviation from established process technology required to do this sounds staggering.


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## rob85635 (Jan 16, 2009)

> heatsinking...refrigerator lamp anyone?



LOL, perfect, hehe.

Rob


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## PhotonWrangler (Jan 16, 2009)

Oznog said:


> My god.... the deviation from established process technology required to do this sounds staggering.



Yep, that's why I'm skeptical about this product. I'm having a hard time imagining a thin, filament-like strip of semiconductor material. This would be so incredibly fragile that even a light shake would probably shatter it. It also makes no sense to me in terms of the "360 degree" light claim, when it's far easier to achieve the same goal with established methods such as LED arrays, mirrors and frosted globes.

One of those photos doesn't even seem real, the second one showing the "lit" version of the flame tip styled bulb. It doesn't seem to match the "unlit" photo of (purportedly) the same lamp.

:shrug:


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## jtr1962 (Jan 16, 2009)

Oznog said:


> My god.... the deviation from established process technology required to do this sounds staggering.


I think that's one of the biggest reasons I said WHY? You have to jump through all these hoops to try and make an LED which looks like a filament. What are you gaining in return other than having something which looks like an incandescent lamp? It'll likely be expensive as hell, not terribly efficient, fragile, and an omnidirectional light pattern really isn't ideal for room lighting. The 180° emission pattern of regular power LEDs is much more suitable. In fact, it's ideal for mounting on a ceiling. The overall goal of LED lighting has been stated many times to be efficiency. If LED lighting ends up taking the direction of imitating filament-based lamps to a tee, then this goal will be severely comprised.


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## Kiessling (Jan 16, 2009)

Why does a LED need to be formed into a filament? Wouldn't it suffice to put lots of tiny chips ON the filament and then pour phosphor all over, the phosphor thus masking the sinlge chips and glowing uniformly?


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## jtr1962 (Jan 16, 2009)

Kiessling said:


> Why does a LED need to be formed into a filament? Wouldn't it suffice to put lots of tiny chips ON the filament and then pour phosphor all over, the phosphor thus masking the sinlge chips and glowing uniformly?


Yes, that would work just fine actually. Even though I question the logic of this whole idea, I'd love to learn more about how they're made. This has to be using some real cutting edge production methods.


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## Kiessling (Jan 16, 2009)

Why cutting edge? You just make a series of LED chips long enough to roughly equal the AC power, connect both ends to power, include a diode to protect from reverse current (or something like that) and you're done.

bernie


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## Oznog (Jan 16, 2009)

_"The rated electric power is 0.6W. The total luminous flux is 18lm, and the luminance efficiency is 30lm/W. The rated life is 20,000 hours. The power consumption is about 1/9 and the lifetime is about 10 times of a 5W ornamental incandescent lamp, according to Ushio Lighting. "_

30 lm/w.... not esp impressive compared to normal incan. BUT, the small low-wattage ornamental incan lamps DO have terrible lumen/w. What's a 5W ornamental, anyways? The flame-tip ones in my ceiling fan are like 40W-60W IIRC. What are the 5W, like those you'd find on an electric candelabra??


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## jtr1962 (Jan 16, 2009)

Kiessling said:


> Why cutting edge? You just make a series of LED chips long enough to roughly equal the AC power, connect both ends to power, include a diode to protect from reverse current (or something like that) and you're done.


And you have to mount all those chips along a thin piece of metal mimicking a filament, connect them all in series with tiny bond wires, and then coat it all with phosphor. We've got the process down for putting single chips in a lead frame, but this seems way more complex. Maybe they're using dies which are connected in series at the wafer level (i.e. one long, thin die). That would simplify things a lot.


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## jtr1962 (Jan 16, 2009)

Oznog said:


> What's a 5W ornamental, anyways? The flame-tip ones in my ceiling fan are like 40W-60W IIRC. What are the 5W, like those you'd find on an electric candelabra??


The 40 to 60 watt ones are only 8 to 10 lm/W. I think a 5 watt ornamental is around 3 to 4 lm/W, if that. So 30 lm/W isn't great by today's standards, but it's probably a factor of 8 to 10 better than what it replaces.


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## Oznog (Jan 16, 2009)

jtr1962 said:


> I think that's one of the biggest reasons I said WHY? You have to jump through all these hoops to try and make an LED which looks like a filament. What are you gaining in return other than having something which looks like an incandescent lamp? It'll likely be expensive as hell, not terribly efficient, fragile, and an omnidirectional light pattern really isn't ideal for room lighting. The 180° emission pattern of regular power LEDs is much more suitable. In fact, it's ideal for mounting on a ceiling. The overall goal of LED lighting has been stated many times to be efficiency. If LED lighting ends up taking the direction of imitating filament-based lamps to a tee, then this goal will be severely comprised.



Hey, I can see the exact same questions... but it's not every day you see somebody come up with something THIS "different". Lots of people are willing to repackage existing tech and call it innovative. Making LEDs in non-flat-die shapes is completely unprecedented. I'm not saying it has to make practical sense... yet. 

Face it, look how many projects here don't even make financial or practical sense no matter how you look at it. We get into talks over how to replace a car headlight with LEDs and we're talking about something that costs hundreds, weeks or months of work, and saves a trivial amount of gasoline and a couple of headlight changes over the life of the car.

It's because it's cool, not because it makes sense.


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## Oznog (Jan 16, 2009)

I'm still boggled- HOW did they make this?? The wafer construction doesn't even sound applicable. Once you deviate from wafer construction, you're basically inventing the LED all over again. Unless they made wafers, chopped them up, and glued them into series stacks as side emitters... which is possible but sounds fantastically difficult.

I really really wanna see one up close. 

Did they encapsulate the dies, or leave it exposed and rely on the inert gas inside the bulb to protect it from the environment?


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## Illum (Jan 16, 2009)

paint = pain mispelt





Pardon the ignorance for technological limitations, but since conventional LEDs uses square P/N junctions, can they be made into cylinders within cylinders as depicted above?


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## jusval (Jan 16, 2009)

Oznog said:


> _"The rated electric power is 0.6W. The total luminous flux is 18lm, and the luminance efficiency is 30lm/W. The rated life is 20,000 hours. The power consumption is about 1/9 and the lifetime is about 10 times of a 5W ornamental incandescent lamp, according to Ushio Lighting. "_
> 
> 30 lm/w.... not esp impressive compared to normal incan. BUT, the small low-wattage ornamental incan lamps DO have terrible lumen/w. What's a 5W ornamental, anyways? The flame-tip ones in my ceiling fan are like 40W-60W IIRC. What are the 5W, like those you'd find on an electric candelabra??


 
It seems that they aren't saying the bulb replaces a 5w incan, but that it consumes only the energy of a 5w incan. Meaning they are trying to say it's much more efficient than an incan and lasts much longer. Seems like the goal is to replace the flame tipped incans by making a LED that looks like one. It's one way to attract die hard incan users. Give them a bulb that's more green friendly, but looks like what they are used to.


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## 2xTrinity (Jan 16, 2009)

Illum_the_nation said:


> paint = pain mispelt
> 
> 
> 
> ...


Short answer: No

Long Answer: 

The way that semiconductors are made as of now is to start with a single HUGE cylindrical single crystal of silicon. Each one of these costs thousands of dollars. They is then sliced into many many of thin wafers. Trying to CUT a smaller cylinder out of a huge cylindrical silicon crystal would be basicaly impossible -- and obscenely expensive to even try. 

It gets worse if you actually want to dope, or introduce any features onto that silicon. In most semiconductors, features are introduced by a process called photolithography -- where a photoresist film is spead uniformly across the wafer (usually by spinning the wafer on a high speed "turntable" of sorts... uniformly distributing a film across a long cylinder would be basically impossible)

The desired features/patterns are then projected using UV light. The photoesist film will then be developed, and the parts not exposed to UV will be washed away, leaving a mask on the surface of the wafer, which can be used to limit etching or doping to a specific region on the wafer. As semiconductor fabrication relies on both optical projection of the features onto a flat surface there aren't really any facilities to fabricate semiconductors that are not on a flat wafer.



> I'm still boggled- HOW did they make this?? The wafer construction doesn't even sound applicable. Once you deviate from wafer construction, you're basically inventing the LED all over again. Unless they made wafers, chopped them up, and glued them into series stacks as side emitters... which is possible but sounds fantastically difficult.


This is what I suspect they actually did. As hard as that sounds, it's still easier than say, using a polygonal (not round) wire as a substrate, mounting LED dice all over it (while insulating them all from each other electrically). Somehow attaching bond wires between all of the LEDs (considering the machines used to attach those bond wires are in fact designed to standard flat wafers... there would be no way to "set down" the filament on the machine used to attach the bond wires without crushing the bond wires on the reverse side... ), THEN depositing phosphor all over.

Stacking a bunch of side-emitting dice one on top of enough, then probably coating the entire thing in phosphor, and then gluing everything together with epoxy is most likely what they did. Which means currents will be limited by the fact that there's basically zero heatsinking. Optical efficiency of extracting light from side emitters is also much worse.

There would also have to be something like 35-40 emitters on this device, for it to be run on AC without some sort of transformer.


Another way it could be done with relatively few LED dice, would be to make a "filament" which is in fact a fiber-optic light guide specifically designed to be "leaky" in some places. It could be coupled to a single high-power emitter that is well-heatsinked, and the light could then be "piped" out to the filament, which is designed to let some light through in select places (eg the "glowing" part of the filament) and act as a total internal reflector elsewhere (say, to get from the hidden LED, up the filament supports, etc.)


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## Oznog (Jan 17, 2009)

http://techon.nikkeibp.co.jp/english/NEWS_EN/20090106/163635/3C.jpg

Embiggened picture.

My theory? Look close and I think I see a wire running down the length. There's a row of 3 LED die on there. One theory is the orangy stuff might not just be diffuser but THE phosphor and the devices are blue LEDs, rather than a homogenous construction for most whites where the phosphor is mounted right on the blue-emitting die. 

Maybe not though. The one on the left looks like 3 devices embedded in cast, yellowish plastic diffuser.

I note that 18x 3.7V whites are being driven with... where's the space for a driver?? We've seen LED bulbs with a CFL-type plastic base. Where would the driver go?? You're not gonna use a ballast resistor to eat up the voltage difference between 120v and 67v. No room for a rectifier even. 

There have been a few cases where devices were designed for that type of socket base but weren't actually 110v devices (there were 12v RV light bulbs done that way). It's possible they could have their own driver-fixture that put out 67v for the devices but that would be really weird, risky too because people can take out those bulbs and try to plug them into 110v sockets, although just adding a fuse generally protects against the worst there.


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## Oznog (Jan 17, 2009)

Hmmm ok if it's actually 0.6W per lamp, then 0.6W/18 devices/3.7v = 9mA for the string.

At that current level, they might just have a series resistor or whatever. In fact we could start with like 60 lumens/w in the LEDs themselves and have the series resistor eat up half the lumens/w value to get to 30 lm/w.

Or hey wait that 0.6W should be for the LEDs AND the "ballast", so there might only be like 0.3W going into those 18x LEDs, and 0.3W into the ballast resistor. That's still plausible. A FWB and half-watt resistor would fit in the base and be cheap-as-shiat.


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## Illum (Jan 17, 2009)

doubtful for ballasts, but I'd expect at minimum 4 IN4001s in there coverting AC to DC. they could mount 2 of the 4 LEDs in reverse and use a huge resistor too...


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## Resqueline (Jan 17, 2009)

Capacitors are commonly used as loss-less current setting elements instead of resistors, only augmented with a small-value series resistor to limit spike-currents. I've even seen them used straight off of 230V instead of transformers in 1.8A drill chargers. (27uF in series with a 1 Ohm.) The current obviously becomes frequency dependent.
I expect that a suitable capacitor, resistor, and bridge rectifier would fit in the E27 base. You can see the E14 base needs an extra plastic collar.


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## HarryN (Apr 26, 2009)

Ah - finally - someone is listening to the wives of the CPF'rs. I have an incan chandelier that only gets used for special occasions. Given the risk that some fool politician will ban incan lights just to get re-elected, we need an LED path to keep the lights on. No way am I going to replace that chandelier - no matter how much I like LEDs.

Regardless of efficiency, it gets used so rarely that there is no effect on the world power supply or way to justify it - no matter if the head of the sierra club owned it.

I would rather go into production of my own incan bulbs than try to convince my wife to replace the bulbs on it with conventionally shaped LEDs.

Of course, long term, most of the lights in the house will be long tube fluorescent or LED - most light output is long tube fl already in my house.


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## ledstein (May 8, 2009)

Such a product is only good in places where one needs light to attract attention, like casinos, xmass decorations, some churches and so on. Still im not sure about the heat management part and lifetime.


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