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75 lm/Watt

  • Thread starter Dirk Bruere at NeoPax
  • Start date
D

Dirk Bruere at NeoPax

Jan 1, 1970
0
http://www.physorg.com/news93198212.html

"Osram has developed a small light-emitting diode spotlight that
achieves an output of more than 1,000 lumens for the first time. That’s
brighter than a 50-watt halogen lamp, thereby making the device suitable
for a broad range of general lighting applications."

--
Dirk

http://www.onetribe.me.uk - The UK's only occult talk show
Presented by Dirk Bruere and Marc Power on ResonanceFM 104.4
http://www.resonancefm.com
 
D

Don Lancaster

Jan 1, 1970
0
Dirk said:
http://www.physorg.com/news93198212.html

"Osram has developed a small light-emitting diode spotlight that
achieves an output of more than 1,000 lumens for the first time. That’s
brighter than a 50-watt halogen lamp, thereby making the device suitable
for a broad range of general lighting applications."

75 lumens per watt is kinda pathetic low end for the latest LED's.

See the free LED JOURNAL.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com
 
J

Joel Kolstad

Jan 1, 1970
0
Don Lancaster said:
75 lumens per watt is kinda pathetic low end for the latest LED's.
See the free LED JOURNAL.

Given that I'm sure the Osram designs red the LED Journal, I wouldn't be
surprised if theirs isn't that horribly efficient based on attempting to
build a commercial viable product with a decent life rather than just some
lab sample that's characterized during 5 minutes of burn-in?
 
J

Jeff L

Jan 1, 1970
0
Dirk Bruere at NeoPax said:
The most I've heard of is 130, but are they being sold or are they
experimental?

That seems typical of some monochrome LED's in production.
 
D

Don Klipstein

Jan 1, 1970
0
75 lumens per watt is kinda pathetic low end for the latest LED's.

See the free LED JOURNAL.

Although announcements well over 100 lumens per watt have been around
for a while, among units actually available upper 60's to 70 is a high end
model, and 75 is a higher brightness binning of a high end model. So if
this thing is out this summer, it will actually be a slight increment over
middle-grade of the most efficient power LEDs that I have seen so far.

Although 75 is low for an announcement of an upcoming product, higher
luminous efficacies have also been at lower powers - generally around 1.2
watts per chip for high power models, as in operating at 350 mA, with the
highest luminous efficacy announcement that I heard of so far being 115 or
so for a laboratory prototype IIRC. There are lower power chips that have
achieved 130 and 150 IIRC - with power input around 66-68 milliwatts (20
milliamps, voltage drop around 3.3 volts), for laboratory prototypes.

- Don Klipstein ([email protected])
 
D

Don Klipstein

Jan 1, 1970
0
http://www.physorg.com/news93198212.html

"Osram has developed a small light-emitting diode spotlight that
achieves an output of more than 1,000 lumens for the first time. That’s
brighter than a 50-watt halogen lamp, thereby making the device suitable
for a broad range of general lighting applications."

Keep in mind they said 75 lumens/watt at 350 mA, and that this is a
6-chip device. At 350 mA, chips of higher efficiency tend to have voltage
drop around 3.3 volts - otherwise 3.5 volts is usual. So at 350 mA, the
voltage drop is close to 20 volts, and the power is close to 7 watts. At
75 lumens/watt, 7 watts gives 525 lumens.

To get 1,000 lumens, current closer to an amp is required, with overall
luminous efficacy not 75 lumens/watt but in the 50's. (I have seen other
announcements on this product.) If this thing achieved 75 lumens/watt at
enough power to deliver 1,000 lumens, they would not have qualified 75
lumens/watt at a current only good for 525 lumens.

- Don Klipstein ([email protected])
 
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Don Klipstein

Jan 1, 1970
0
So it appears that for visible wavelengths (inc white light) LEDs will
soon be the most efficient.

Most efficient white light sources now in production and available are
many models of metal halide lamps, some of which exceed 100 lumens/watt.

As for whitish, 1KW high pressure sodium lamps get a good 140
lumens/watt.

As for visible light lamps, 180 watt SOX low pressure sodium lamps get
180 lumens/watt.

Keep in mind that T8 fluorescents on high frequency electronic ballasts
easily get about 95, in the 80's even after ballast losses. In more
optimistic situations, T5 and T8 fluorescent lamps with high frequency
electronic ballasts crack a bit past 100, and get into the 90's even
after ballast losses. A nominally 32 watt T8, often given upper 20's of
watts by many high frequency electronic ballasts, costs maybe $2.50 each
at home centers, and has rated life expectancy in typical commercial duty
usage 20,000 hours or so.

- Don Klipstein ([email protected])
 
D

Don Klipstein

Jan 1, 1970
0
That seems typical of some monochrome LED's in production.

Actually, I have yet to hear of monochrome LEDs of such overall luminous
efficacy being available. The high conversion efficiencies apear to me to
be in blue and red, which are not the best for high lumens/watt.

It appears to me that maximum possible overall luminous efficacy would
be for a blue LED chip to have its output entirely fluoresced into green
or yellow, but there is little effort there since the big money is after
white. So we have blue LED chips combined with a broadband yellow-glowing
phosphor producing red through green, and the phosphor coating is thin
enough to let some of the blue light through.

These phosphors are not perfect and have some losses. For one thing, it
appears to me that a layer of blue-utilizing phosphor thick enough to give
a "warm white" color loses enough light to result in lower overall
luminous efficacy than is available with a "cool white" achieved with a
thinner phosphor layer. The latest high lumen/watt figures for laboratory
prototypes tend to have color temperatures in the 4,000's to about 5,000
Kelvin. Most white LEDs already in production have even higher color
temperature - in the 5,000's and 6,000's and I have seen some even
higher (a noticeably bluish shade of white). I suspect yellow would fare
worse than warm white. Perhaps the most efficient yellow LED one can get
today is a white LED with a yellow filter over it.

- Don Klipstein ([email protected])
 
D

Don Lancaster

Jan 1, 1970
0
Don said:
A nominally 32 watt T8, often given upper 20's of
watts by many high frequency electronic ballasts, costs maybe $2.50 each
at home centers, and has rated life expectancy in typical commercial duty
usage 20,000 hours or so.

- Don Klipstein ([email protected])

I have yet to see ANY CCFL last as long as in incandescent.

Ever.

Their quality control is mesmerizingly awful.

--
Many thanks,

Don Lancaster voice phone: (928)428-4073
Synergetics 3860 West First Street Box 809 Thatcher, AZ 85552
rss: http://www.tinaja.com/whtnu.xml email: [email protected]

Please visit my GURU's LAIR web site at http://www.tinaja.com
 
D

Don Klipstein

Jan 1, 1970
0
I have yet to see ANY CCFL last as long as in incandescent.

Ever.

Their quality control is mesmerizingly awful.

You are mentioning CCFLs? Those aren't the usual compact fluorescent
lamps, but cold cathode fluorescent lamps. CCFL usually refers to the
miniature ones often used for LCD backlights and in scanners. The cold
cathode ones don't burn out the way the hot cathode ones do, and do not
have problems with frequent starting.
There is even a CCFL home lighting product available at Home Depot now -
at least it appears to me to be a CCFL. It is the N:Vision 3-watt
candelabra base unit among the CFLs. If it dies, it would be due to
breakage or from failure of the voltage boosting circuit.

As for CFLs, I have a lot of experience with them. I have experience
with them in my home, homes of relatives, and in locations that I have
been at frequently.
I have seen some early failures concentrated into brands that I hear
enough about being prone to early failures. I have seen some early
failures in what appears to me to be one bad production run of a "Big 3"
brand. I have seen some early failures from abuse - such as used where
they will overheat, such as in recessed ceiling fixtures. And I have seen
a few early failures for no good reason. But CFLs do mostly outlast
"standard" incandescents by a factor of a few times.

I have seen plenty last long enough for the phosphor to noticeably
degrade. That makes it easy to tell when they get replaced.

- Don Klipstein ([email protected])
 
J

joseph2k

Jan 1, 1970
0
Joel said:
Given that I'm sure the Osram designs red the LED Journal, I wouldn't be
surprised if theirs isn't that horribly efficient based on attempting to
build a commercial viable product with a decent life rather than just some
lab sample that's characterized during 5 minutes of burn-in?
Actually, California Department of Transportation, Los Angeles Bureau of
Street Lighting, Arizona Department of Transportation, and many others have
been watching LED lighting to replace current HPS systems. They will move
soon after it becomes cost effective. A lot like LED traffic signals,
required now for new installations and usually for any upgrade at every
signal intersection. 1/6 the power is a real incentive, long term; not to
mention 1/20 the maintenance.
 
D

Don Klipstein

Jan 1, 1970
0
Actually, California Department of Transportation, Los Angeles Bureau of
Street Lighting, Arizona Department of Transportation, and many others have
been watching LED lighting to replace current HPS systems. They will move
soon after it becomes cost effective. A lot like LED traffic signals,
required now for new installations and usually for any upgrade at every
signal intersection. 1/6 the power is a real incentive, long term; not to
mention 1/20 the maintenance.

I am sure plenty are watching LEDs for streetlights - and currently
doing nothing but watching.

As for traffic lights, those are easy for LEDs to beat bigtime in
efficiency. There are a couple reasons:

1) The incandescents in traffic lights are not "standard" incandescents,
but ones with vibration resistant filaments and with design life
expectancy usually 8,000 hours. Traffic signal lamps have about 2/3 the
efficiency of standard incandescents of similar wattage.

2) The red and green filters remove about 2/3 of the light. The yellow
filters remove less, but the yellow signals account for only about 5% of
the duty - sometimes less. Meanwhile, LEDs are good at specializing in
production of light of a particular color.

- Don Klipstein ([email protected])
 
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