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Lumen (unit)
Lumen (unit)
Published: 2014/08/05
Channel: Audiopedia
Integral LED - What are lumens?
Integral LED - What are lumens?
Published: 2013/10/03
Channel: Integral LED
Testing in the Lumen Starter
Testing in the Lumen Starter
Published: 2016/05/13
Channel: Realpage DevOps
HCM_HALO 900,000 LUMEN UNIT
HCM_HALO 900,000 LUMEN UNIT
Published: 2015/10/08
Channel: Apollo Energy Services
** lumen lux candela Teil 1
** lumen lux candela Teil 1
Published: 2012/12/19
Channel: Stephan Mueller
Lumen (unit)
Lumen (unit)
Published: 2016/01/29
Channel: WikiAudio
Feniex Focus Episode 2 // Measuring Light Intensity for Emergency Vehicles
Feniex Focus Episode 2 // Measuring Light Intensity for Emergency Vehicles
Published: 2015/05/18
Channel: Feniex Industries
Quality light system from HEINE
Quality light system from HEINE
Published: 2015/05/12
Channel: HeineOptotechnik
What Is a Lumen
What Is a Lumen
Published: 2014/01/26
Channel: JPChannel100
Lumen Meaning
Lumen Meaning
Published: 2015/04/13
Channel: SDictionary
Flashlight review comparison: lumen output vs beam distance
Flashlight review comparison: lumen output vs beam distance
Published: 2015/05/27
Channel: Light Junction
What are Lumens?
What are Lumens?
Published: 2014/09/05
Channel: TCP Lighting
Understanding Lumens, Tactical Flashlight Beam Pattern & Brightness - Elzetta vlog episode 1
Understanding Lumens, Tactical Flashlight Beam Pattern & Brightness - Elzetta vlog episode 1
Published: 2014/05/30
Channel: ElzettaDesign
Review Home Depot Husky 5 ft 800 Lumen Portable LED Work Light 480624 - Bundys Garage
Review Home Depot Husky 5 ft 800 Lumen Portable LED Work Light 480624 - Bundys Garage
Published: 2014/03/29
Channel: BundysGarage
1000W LED Flashlight - Worlds Brightest (90,000 Lumens)
1000W LED Flashlight - Worlds Brightest (90,000 Lumens)
Published: 2015/11/21
Channel: rctestflight
CCCOER Webinar: Open Course Design and Development with UMUC, Lumen, and Nova Community College
CCCOER Webinar: Open Course Design and Development with UMUC, Lumen, and Nova Community College
Published: 2014/10/12
Channel: Open Education Consortium
The UNiT FARM UFO-80 L.E.D. Video one in a series. Featuring Cree & Osram
The UNiT FARM UFO-80 L.E.D. Video one in a series. Featuring Cree & Osram
Published: 2017/07/05
Channel: Drew Grow
LED Vs Halogen Vs Fluro Work Lights The Watts & Lumens Lighting Scam
LED Vs Halogen Vs Fluro Work Lights The Watts & Lumens Lighting Scam
Published: 2013/04/06
Channel: leokimvideo
1W | LED Built-in Spotlight | Square Mini Unit | 90-100 Lumen
1W | LED Built-in Spotlight | Square Mini Unit | 90-100 Lumen
Published: 2015/08/03
Channel: LEDFIX Solutions LTD
WoW Addon - oUF Lumen (мини юнит фреймы / minimalistic unit frames)
WoW Addon - oUF Lumen (мини юнит фреймы / minimalistic unit frames)
Published: 2016/09/27
Channel: Likos
Water Cooled 72,000 Lumen LED Flashlight!!
Water Cooled 72,000 Lumen LED Flashlight!!
Published: 2016/04/27
Channel: Samm Sheperd
Lumen Industries CP-32 Mushroom Unit
Lumen Industries CP-32 Mushroom Unit
Published: 2011/07/09
Channel: Colin Yeadon
What Is The Medical Definition Of Lumen?
What Is The Medical Definition Of Lumen?
Published: 2017/09/19
Channel: S AnswerZ
LUMEN CRAFT - RISING PRIZE (BalconyTV)
LUMEN CRAFT - RISING PRIZE (BalconyTV)
Published: 2016/11/18
Channel: BalconyTV
Quad Cree XM-L U2 ED based 3100 Lumen + In-Line LED Multifunction Control Unit
Quad Cree XM-L U2 ED based 3100 Lumen + In-Line LED Multifunction Control Unit
Published: 2015/01/04
Channel: Pálinkás Mihály
Verbatim LED Tutorial3: Lumen and candela explained
Verbatim LED Tutorial3: Lumen and candela explained
Published: 2013/07/11
Channel: Verbatim40
JNHM _  Lumen _  Beat
JNHM _ Lumen _ Beat
Published: 2017/03/16
Channel: J-N-H-M
Honeywell LED 1500 Lumen Security Light (MA0021)
Honeywell LED 1500 Lumen Security Light (MA0021)
Published: 2017/10/18
Channel: eAccess Solutions Inc
Promier 400 Lumen COB LED Jumbo Pocket Light PTSK-8-32
Promier 400 Lumen COB LED Jumbo Pocket Light PTSK-8-32
Published: 2016/12/08
Channel: Promier The Evolution of Light
Pyrotech   Lumen per watt of LED Lights
Pyrotech Lumen per watt of LED Lights
Published: 2017/02/06
Channel: Pyrotech Electronics Pvt. Ltd. Unit-1
New 600 Lumen Surefire X300B-U: Overview & Impression
New 600 Lumen Surefire X300B-U: Overview & Impression
Published: 2015/10/16
Channel: Tactical Lobster
ThruNite Ti3 - 120 Lumen Keychain Flashlight
ThruNite Ti3 - 120 Lumen Keychain Flashlight
Published: 2014/10/03
Channel: Gear Obsession
Joakim Arenius & Praise Unit - Festival Lumen 2012
Joakim Arenius & Praise Unit - Festival Lumen 2012
Published: 2012/06/25
Channel: FestivalLumen
Solar Powered Motion Light - 1000 Lumen LED Security
Solar Powered Motion Light - 1000 Lumen LED Security
Published: 2017/10/03
Channel: Deelat Industrial USA
Torture Testing:  ATACTICAL A1 LED 550 Lumen Flashlight
Torture Testing: ATACTICAL A1 LED 550 Lumen Flashlight
Published: 2017/04/04
Channel: IntoWeapons
Maxxima MPWL-10 | Portable Rechargeable Lithium 800 Lumen LED Work Light
Maxxima MPWL-10 | Portable Rechargeable Lithium 800 Lumen LED Work Light
Published: 2016/08/12
Channel: Maxxima Heavy Duty LED Lighting
Gewusst wie.... Was bedeutet Lumen?
Gewusst wie.... Was bedeutet Lumen?
Published: 2015/01/07
Channel: Wohnlicht.com
Universal (CANBUS) Phillips 2400 lumen 6-24VDC LED bulb
Universal (CANBUS) Phillips 2400 lumen 6-24VDC LED bulb
Published: 2015/04/25
Channel: Brett Beisker
Solstice brand LED Lamp replacement kit. 135 Lumen per watt
Solstice brand LED Lamp replacement kit. 135 Lumen per watt
Published: 2009/05/15
Channel: vortexentity
Blue Forklift LED Warning Spotlight - 25 Watt 2250 Lumen - 9-60V DC - Blue Pedestrian Safety Light
Blue Forklift LED Warning Spotlight - 25 Watt 2250 Lumen - 9-60V DC - Blue Pedestrian Safety Light
Published: 2016/04/11
Channel: Larson Electronics
[C9 Thailand] 21/10/2017 Warden & Lumen Empress Duo Dimensional Boss
[C9 Thailand] 21/10/2017 Warden & Lumen Empress Duo Dimensional Boss
Published: 2017/10/22
Channel: iAmhere /
High Intensity LED on Extending Work Light Pole - 150 Watts - 14,790 Lumen - AC or DC
High Intensity LED on Extending Work Light Pole - 150 Watts - 14,790 Lumen - AC or DC
Published: 2014/11/14
Channel: Larson Electronics
First Test Ride with "2000 Lumen" Bike Light from eBay
First Test Ride with "2000 Lumen" Bike Light from eBay
Published: 2015/10/20
Channel: James Sealey
Smart 700 lumen front bike light review
Smart 700 lumen front bike light review
Published: 2015/10/04
Channel: oovelo love cycling
Guide Gear 220-lumen Flashlight
Guide Gear 220-lumen Flashlight
Published: 2011/04/22
Channel: BargainOutfitters
10 Million Candlepower LED Spotlight - 36 Watt - Pistol Grip - 1600 Foot Beam - 2000 Lumens
10 Million Candlepower LED Spotlight - 36 Watt - Pistol Grip - 1600 Foot Beam - 2000 Lumens
Published: 2016/03/23
Channel: Larson Electronics
Explosion Proof Blue Forklift LED Warning Spotlight - C1D1 - 25 Watt 2250 Lumen - 9-60V DC
Explosion Proof Blue Forklift LED Warning Spotlight - C1D1 - 25 Watt 2250 Lumen - 9-60V DC
Published: 2016/06/15
Channel: Larson Electronics
Dakine Lumen SKU:8538581
Dakine Lumen SKU:8538581
Published: 2016/07/29
Channel: Shop Zappos
LED Bulb Buying Guide, What is  Lumens/watt, Colour rendering index, Colour temperature
LED Bulb Buying Guide, What is Lumens/watt, Colour rendering index, Colour temperature
Published: 2017/11/11
Channel: Zaroori Baatein
580 Lumen Professional Rechargeable LED Torch (Maplin A10LN)
580 Lumen Professional Rechargeable LED Torch (Maplin A10LN)
Published: 2014/05/16
Channel: MaplinTV
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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The lumen (symbol: lm) is the SI derived unit of luminous flux, a measure of the total quantity of visible light emitted by a source. Luminous flux differs from power (radiant flux) in that radiant flux includes all electromagnetic waves emitted, while luminous flux is weighted according to a model (a "luminosity function") of the human eye's sensitivity to various wavelengths. Lumens are related to lux in that one lux is one lumen per square meter.

The lumen is defined in relation to the candela as

1 lm = 1 cdsr.

A full sphere has a solid angle of 4π steradians,[1] so a light source that uniformly radiates one candela in all directions has a total luminous flux of 1 cd × 4π sr = 4π cd⋅sr ≈ 12.57 lumens.[2]

Explanation[edit]

If a light source emits one candela of luminous intensity uniformly across a solid angle of one steradian, the total luminous flux emitted into that angle is one lumen (1 cd·1 sr = 1 lm). Alternatively, an isotropic one-candela light-source emits a total luminous flux of exactly 4π lumens. If the source were partly covered by an ideal absorbing hemisphere, that system would radiate half as much luminous flux—only 2π lumens. The luminous intensity would still be one candela in those directions that are not obscured.

The lumen can be thought of casually as a measure of the total "amount" of visible light in some defined beam or angle, or emitted from some source. The number of candelas or lumens from a source also depends on its spectrum, via the nominal response of the human eye as represented in the luminosity function.

The difference between the units lumen and lux is that the lux takes into account the area over which the luminous flux is spread. A flux of 1000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1000 lux. The same 1000 lumens, spread out over ten square metres, produces a dimmer illuminance of only 100 lux. Mathematically, 1 lx = 1 lm/m2.

A source radiating a power of one watt of light in the color for which the eye is most efficient (a wavelength of 555 nm, in the green region of the optical spectrum) has luminous flux of 683 lumens. So a lumen represents at least 1/683 watts of visible light power, depending on the spectral distribution.

Lighting[edit]

A standard LED lamp capable of producing 470 lumens. It consumes about one sixth the energy of an incandescent light bulb producing the same light.

Lamps used for lighting are commonly labelled with their light output in lumens; in many jurisdictions this is required by law.

A 23 W spiral compact fluorescent lamp emits about 1,400–1,600 lm.[3][4] Many compact fluorescent lamps and other alternative light sources are labelled as being equivalent to an incandescent bulb with a specific wattage. Below is a table that shows typical luminous flux for common incandescent bulbs and their equivalents.

Electrical power equivalents for differing lamps[5][6]
Minimum light output (lumens) Electrical power consumption (watts)
Incandescent (non-halogen) Compact fluorescent LED
200 25 3-5 3[7]
450 40 9–11 5–8
800 60 13–15 8–12
1,100 75 18–20 10–16
1,600 100 24–28 14–17
2,400 150 30–52 24-30[8]
3,100 200 49–75 32[9]
4,000 300 75–100 40.5[10]

On September 1, 2010, European Union legislation came into force mandating that lighting equipment must be labelled primarily in terms of luminous flux (lm), instead of electric power (W).[11] This change is a result of the EU's Eco-design Directive for Energy-using Products (EuP).[12] For example, according to the European Union standard, an energy-efficient bulb that claims to be the equivalent of a 60 W tungsten bulb must have a minimum light output of 700–750 lm.[13]

Projector output[edit]

ANSI lumens[edit]

The light output of projectors (including video projectors) is typically measured in lumens. A standardized procedure for testing projectors has been established by the American National Standards Institute, which involves averaging together several measurements taken at different positions.[14] For marketing purposes, the luminous flux of projectors that have been tested according to this procedure may be quoted in "ANSI lumens", to distinguish them from those tested by other methods. ANSI lumen measurements are in general more accurate than the other measurement techniques used in the projector industry.[15] This allows projectors to be more easily compared on the basis of their brightness specifications.

The method for measuring ANSI lumens is defined in the IT7.215 document which was created in 1992. First the projector is set up to display an image in a room at a temperature of 25 degrees Celsius. The brightness and contrast of the projector are adjusted so that on a full white field, it is possible to distinguish between a 5% screen area block of 95% peak white, and two identically sized 100% and 90% peak white boxes at the center of the white field. The light output is then measured on a full white field at nine specific locations around the screen and averaged. This average is then multiplied by the screen area to give the brightness of the projector in "ANSI lumens".[16]

Peak lumens[edit]

Peak lumens is a measure of light output normally used with CRT video projectors. The testing uses a test pattern typically at either 10 and 20 percent of the image area as white at the center of the screen, the rest as black. The light output is measured just in this center area. Limitations with CRT video projectors result in them producing greater brightness when just a fraction of the image content is at peak brightness. For example, the Sony VPH-G70Q CRT video projector produces 1200 "peak" lumens but just 200 ANSI lumens.[17]

Color light output[edit]

Brightness (white light output) measures the total amount of light projected in lumens. The color brightness specification Color Light Output measures red, green, and blue each on a nine-point grid, using the same approach as that used to measure brightness. Experts advise projector buyers to make certain that white light output and color light output are equal for optimum viewing experiences.[citation needed]

SI photometry units[edit]

SI photometry quantities
Quantity Unit Dimension Notes
Name Symbol[nb 1] Name Symbol Symbol
Luminous energy Qv [nb 2] lumen second lm⋅s TJ [nb 3] The lumen second is sometimes called the talbot.
Luminous flux / luminous power Φv [nb 2] lumen (= cd⋅sr) lm J [nb 3] Luminous energy per unit time
Luminous intensity Iv candela (= lm/sr) cd J [nb 3] Luminous flux per unit solid angle
Luminance Lv candela per square metre cd/m2 L−2J Luminous flux per unit solid angle per unit projected source area. The candela per square metre is sometimes called the nit.
Illuminance Ev lux (= lm/m2) lx L−2J Luminous flux incident on a surface
Luminous exitance / luminous emittance Mv lux lx L−2J Luminous flux emitted from a surface
Luminous exposure Hv lux second lx⋅s L−2TJ Time-integrated illuminance
Luminous energy density ωv lumen second per cubic metre lm⋅s⋅m−3 L−3TJ
Luminous efficacy η [nb 2] lumen per watt lm/W M−1L−2T3J Ratio of luminous flux to radiant flux or power consumption, depending on context
Luminous efficiency / luminous coefficient V 1 Luminous efficacy normalized by the maximum possible efficacy
See also: SI · Photometry · Radiometry
  1. ^ Standards organizations recommend that photometric quantities be denoted with a suffix "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967
  2. ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ or K for luminous efficacy.
  3. ^ a b c "J" here is the symbol for the dimension of luminous intensity, not the symbol for the unit joule.

See also[edit]

Notes and references[edit]

  1. ^ "Lesson introduction to solid angles". Retrieved Oct 4, 2010. 
  2. ^ Bryant, Robert H. "Lumens, Illuminance, Foot-candles and bright shiny beads…". The LED Light. Retrieved Oct 4, 2010. 
  3. ^ "OSRAM Dulux Energisparepærer" (PDF). Osram.dk. Archived from the original (pdf) on March 1, 2012. Retrieved May 25, 2013. 
  4. ^ "Conventional CFLs". Energy Federation Incorporated. Archived from the original on 2008-10-14. Retrieved Dec 23, 2008. 
  5. ^ "Learn About Light Output : ENERGY STAR". Energystar.gov. Retrieved 2012-07-15. 
  6. ^ "LED Light Bulb Buying Guide". The Lightbulb Company. 11 August 2016. Retrieved 16 November 2017. 
  7. ^ for example: https://www.amazon.com/Bulbs-Incandescent-Equivalent-Dimmable-200lm/dp/B00KYK07OU
  8. ^ one example has been found, at URL: https://www.amazon.com/PacLights-Ultra150-Performance-Equivalent-Replacement/dp/B00F9CM49Y
  9. ^ Philips Luxeon CoB emitters, specifically LHC1-4090-1208 datasheet http://www.philipslumileds.com/uploads/419/DS115-pdf
  10. ^ Philips Luxeon CoB emitters, specifically LHC1-4090-1211 datasheet http://www.philipslumileds.com/uploads/419/DS115-pdf
  11. ^ "Lighting now labelled in lumens". England: National Physical Laboratory. Retrieved March 10, 2012. 
  12. ^ "Ecodesign for energy-using appliances". Summaries of EU legislation. the EU institutions. Feb 2, 2010. Retrieved March 10, 2012. 
  13. ^ "Energy-saving light bulbs: how to read the packaging". European Commission. Archived from the original on 28 June 2013. Retrieved March 10, 2012. 
  14. ^ "ANSI lumen article". PC Magazine Encyclopedia. Retrieved Dec 20, 2006. 
  15. ^ "Projector Guide". CPILive.net. February 2004. Archived from the original on September 3, 2006. Retrieved Dec 20, 2006. 
  16. ^ "ANSI method of light output measurement". 1993. Archived from the original (doc) on February 26, 2012. Retrieved Jan 15, 2008. 
  17. ^ "Sony G70 Brochure" (PDF). 

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