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75 lm/Watt

Discussion in 'Electronic Design' started by Dirk Bruere at NeoPax, Mar 15, 2007.

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  1. 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
     
  2. 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:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  3. The most I've heard of is 130, but are they being sold or are they
    experimental?

    --
    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
     
  4. Joel Kolstad

    Joel Kolstad Guest

    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?
     
  5. Joop

    Joop Guest

    This list seems to be kept reasonably up to date (also see reference
    list)
    http://en.wikipedia.org/wiki/Luminous_efficacy

    If so, then for production units 75 lm/W does not seem bad at all.

    Joop
     
  6. So it appears that for visible wavelengths (inc white light) LEDs will
    soon be the most efficient.
     
  7. Jeff L

    Jeff L Guest

    That seems typical of some monochrome LED's in production.
     
  8. 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 ()
     
  9. 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 ()
     
  10. 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 ()
     
  11. 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 ()
     
  12. 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:

    Please visit my GURU's LAIR web site at http://www.tinaja.com
     
  13. 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 ()
     
  14. joseph2k

    joseph2k Guest

    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.
     
  15. 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 ()
     
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