У этого термина существуют и другие значения, см. Люмен (значения).
Лю́мен (обозначение: лм, lm) — единица измерения светового потока в Международной системе единиц (СИ).
Один люмен равен световому потоку, испускаемому точечным изотропным источником, c силой света, равной одной канделе, в телесный угол величиной в один стерадиан (1 лм = 1 кд × ср). Полный световой поток, создаваемый изотропным источником, с силой света одна кандела, равен 
люменам.
Световой поток типичных источников
| Тип | Световой поток (люмен) | Световая отдача (лм/ватт) |
|---|---|---|
| Лампа накаливания 5 Вт | 20 | 4 |
| Лампа накаливания 10 Вт | 50 | 5 |
| Лампа накаливания 15 Вт | 90 | 6 |
| Лампа накаливания 20 Вт | 140-160 | 7 |
| Лампа накаливания 40 Вт | 415—460[1] | 10 |
| Лампа накаливания 60 Вт | 790—830[1] | 13 |
| Лампа накаливания 100 Вт | 1550—1630[1] | 15 |
| Лампа накаливания 200 Вт | 2860—2960[1] | 15 |
| Галогенная лампа накаливания 55 Вт | 1400—1600[1] | 27 |
| Газоразрядная лампа 35 Вт («автомобильный ксенон») | 3000—3400 | 93 |
| Натриевая газоразрядная лампа 430 Вт (Philips SON AGRO) | 48600[2] | 113 |
| Светодиод Luminus CSM-360 40-80 Вт | 6000[3] | 115 |
| Люминесцентная лампа 40 Вт | 2000 | 50 |
| Люминесцентная лампа Navigator 8U-200 200 Вт | 11400 | 57 |
| Люминесцентная лампа Philips MASTER TL-D Super 80 36W/835 | 3350 | 93 |
| Индукционная лампа 40 Вт | 2800 | 90 |
| Солнце | 3,63·1028[4] | 93 |
Кратные и дольные единицы
Десятичные кратные и дольные единицы образуются с помощью стандартных приставок СИ.
| Кратные | Дольные | ||||||
|---|---|---|---|---|---|---|---|
| величина | название | обозначение | величина | название | обозначение | ||
| 101 лм | декалюмен | далм | dalm | 10−1 лм | децилюмен | длм | dlm |
| 102 лм | гектолюмен | глм | hlm | 10−2 лм | сантилюмен | слм | clm |
| 103 лм | килолюмен | клм | klm | 10−3 лм | миллилюмен | млм | mlm |
| 106 лм | мегалюмен | Млм | Mlm | 10−6 лм | микролюмен | мклм | µlm |
| 109 лм | гигалюмен | Глм | Glm | 10−9 лм | нанолюмен | нлм | nlm |
| 1012 лм | тералюмен | Тлм | Tlm | 10−12 лм | пиколюмен | плм | plm |
| 1015 лм | петалюмен | Плм | Plm | 10−15 лм | фемтолюмен | флм | flm |
| 1018 лм | эксалюмен | Элм | Elm | 10−18 лм | аттолюмен | алм | alm |
| 1021 лм | зетталюмен | Злм | Zlm | 10−21 лм | зептолюмен | злм | zlm |
| 1024 лм | йотталюмен | Илм | Ylm | 10−24 лм | йоктолюмен | илм | ylm |
| применять не рекомендуется |
См. также
- Кандела
- Люкс
- Световая отдача
Примечания
- ↑ 1 2 3 4 5 ГОСТ Р МЭК 60064-99.
- ↑ SON AGRO 430 Watt HPS Lamps
- ↑ Светодиод Luminus CSM-360
- ↑ Световая отдача Солнца — По материалам публикации проф. П. Маркса из журнала «Licht»
|
Единицы СИ |
||
|---|---|---|
| Основные единицы | Ампер · Кандела · Кельвин · Килограмм · Метр · Моль · Секунда |  |
| Производные единицы | Беккерель · Ватт · Вебер · Вольт · Генри · Герц · Градус Цельсия · Грей · Джоуль · Зиверт · Катал · Кулон · Люкс · Люмен · Ньютон · Ньютон-метр · Ом · Паскаль · Радиан · Сименс · Стерадиан · Тесла · Фарад | |
| Астрономическая единица · Гектар · Градус дуги · Дальтон (Атомная единица массы) · День · Децибел · Литр · Минута · Минута дуги · Непер · Секунда дуги · Тонна · Час · Электронвольт Атомная система единиц · Природная система единиц |
||
| См. также | Приставки СИ · Система физических величин · Преобразование единиц · Новые определения СИ · История метрической системы | |
 Книга:СИ ·  Категория:Единицы СИ |
From Wikipedia, the free encyclopedia
| lumen | |
|---|---|
| Unit system | SI |
| Unit of | luminous flux |
| Symbol | lm |
| Conversions | |
| 1 lm in … | … is equal to … |
| SI base units | cd⋅sr[a] |
The lumen (symbol: lm) is the unit of luminous flux, a measure of the total quantity of visible light emitted by a source per unit of time, in the International System of Units (SI). 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. One lux is one lumen per square metre.
The lumen is defined in relation to the candela as
- 1 lm = 1 cd·sr.
A full sphere has a solid angle of 4π steradians,[2] 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 lm.[3]
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 1,000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1,000 lux. The same 1,000 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]
Lamps used for lighting are commonly labelled with their light output in lumens and, in many jurisdictions, that is required by law.
A 23 W spiral compact fluorescent lamp emits about 1,400–1,600 lm.[4][5] Many compact fluorescent lamps and other alternative light sources are labelled as being equivalent to an incandescent bulb with a specific power. Below is a table that shows typical luminous flux for common incandescent bulbs and their equivalents.
| Minimum light output (lumens) | Electrical power consumption (watts) | |||
|---|---|---|---|---|
| Incandescent | Compact fluorescent | LED | ||
| Non-halogen | Halogen | |||
| 90 | 15 | 6 | 2–3 | 1–2 |
| 200 | 25 | 3–5 | 3 | |
| 450 | 40 | 29 | 9–11 | 5–8 |
| 800 | 60 | 13–15 | 8–12 | |
| 1,100 | 75 | 53 | 18–20 | 10–16 |
| 1,600 | 100 | 72 | 24–28 | 14–17 |
| 2,400 | 150 | 30–52 | 24–30[9] | |
| 3,100 | 200 | 49–75 | 32[10] | |
| 4,000 | 300 | 75–100 | 40.5[11] |
On 1 September 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).[12] That change is a result of the EU’s Eco-design Directive for Energy-using Products (EuP).[13] 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.[14]
To estimate lumens from watts for various types of lamp, see luminous efficacy.
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.[15] 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.[16] 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 °C (77 °F). 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».[17]
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.[18]
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.
SI photometric units[edit]
| Quantity | Unit | Dimension | Notes | ||
|---|---|---|---|---|---|
| Name | Symbol[nb 1] | Name | Symbol | Symbol[nb 2] | |
| Luminous energy | Qv[nb 3] | lumen second | lm⋅s | T J | The lumen second is sometimes called the talbot. |
| Luminous flux, luminous power | Φv[nb 3] | lumen (= candela steradian) | lm (= cd⋅sr) | J | Luminous energy per unit time |
| Luminous intensity | Iv | candela (= lumen per steradian) | cd (= lm/sr) | J | Luminous flux per unit solid angle |
| Luminance | Lv | candela per square metre | cd/m2 (= lm/(sr⋅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 (= lumen per square metre) | lx (= lm/m2) | L−2J | Luminous flux incident on a surface |
| Luminous exitance, luminous emittance | Mv | lumen per square metre | lm/m2 | L−2J | Luminous flux emitted from a surface |
| Luminous exposure | Hv | lux second | lx⋅s | L−2T J | Time-integrated illuminance |
| Luminous energy density | ωv | lumen second per cubic metre | lm⋅s/m3 | L−3T J | |
| Luminous efficacy (of radiation) | K | lumen per watt | lm/W | M−1L−2T3J | Ratio of luminous flux to radiant flux |
| Luminous efficacy (of a source) | η[nb 3] | lumen per watt | lm/W | M−1L−2T3J | Ratio of luminous flux to power consumption |
| Luminous efficiency, luminous coefficient | V | 1 | Luminous efficacy normalized by the maximum possible efficacy | ||
| See also: SI · Photometry · Radiometry |
- ^ Standards organizations recommend that photometric quantities be denoted with a subscript «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
- ^ The symbols in this column denote dimensions; «L«, «T» and «J» are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.
- ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.
See also[edit]
- André Blondel
- Brightness
- Luminous efficacy
- Lux
- Nit (unit)
Notes[edit]
- ^ The 9th edition of the SI Brochure gives cd⋅sr as the lumen expressed in terms of base units, although the steradian (sr) is itself listed as a derived unit.[1]
References[edit]
- ^ The International System of Units (SI) (PDF) (9th ed.). Bureau International des Poids et Mesures. 2019. pp. 137–138.
- ^ «Lesson introduction to solid angles». Retrieved Oct 4, 2010.
- ^ Bryant, Robert H. «Lumens, Illuminance, Foot-candles and bright shiny beads…». The LED Light. Retrieved Oct 4, 2010.
- ^
«OSRAM Dulux Energisparepærer» (PDF). Osram.dk. Archived from the original (PDF) on March 1, 2012. Retrieved May 25, 2013. - ^
«Conventional CFLs». Energy Federation Incorporated. Archived from the original on 2008-10-14. Retrieved Dec 23, 2008. - ^ «Learn About Light Output : ENERGY STAR». Energystar.gov. Retrieved 2012-07-15.
- ^ «LED Light Bulb Buying Guide». The Lightbulb Company. 11 August 2016. Retrieved 16 November 2017.
- ^ «Halogen lamps». www.westinghouse.com. Westinghouse. Retrieved 10 March 2020.
- ^ one example has been found, at URL: https://www.amazon.com/PacLights-Ultra150-Performance-Equivalent-Replacement/dp/B00F9CM49Y
- ^ Philips Luxeon CoB emitters, specifically LHC1-4090-1208 datasheet http://www.philipslumileds.com/uploads/419/DS115-pdf
- ^ Philips Luxeon CoB emitters, specifically LHC1-4090-1211 datasheet http://www.philipslumileds.com/uploads/419/DS115-pdf
- ^ «Lighting now labelled in lumens». England: National Physical Laboratory. Retrieved March 10, 2012.
- ^ «Ecodesign for energy-using appliances». Summaries of EU legislation. the EU institutions. Feb 2, 2010. Retrieved March 10, 2012.
- ^ «Energy-saving light bulbs: how to read the packaging». European Commission. Archived from the original on 28 June 2013. Retrieved March 10, 2012.
- ^ «ANSI lumen article». PC Magazine Encyclopedia. Retrieved Dec 20, 2006.
- ^ «Projector Guide». CPILive.net. February 2004. Archived from the original on September 3, 2006. Retrieved Dec 20, 2006.
- ^ «ANSI method of light output measurement». 1993. Archived from the original (doc) on February 26, 2012. Retrieved Jan 15, 2008.
- ^ «Sony G70 Brochure» (PDF).
External links[edit]
- International Lighting Vocabulary 2nd Edition (online searchable version of international standard CIE S 017:2020
From Wikipedia, the free encyclopedia
| lumen | |
|---|---|
| Unit system | SI |
| Unit of | luminous flux |
| Symbol | lm |
| Conversions | |
| 1 lm in … | … is equal to … |
| SI base units | cd⋅sr[a] |
The lumen (symbol: lm) is the unit of luminous flux, a measure of the total quantity of visible light emitted by a source per unit of time, in the International System of Units (SI). 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. One lux is one lumen per square metre.
The lumen is defined in relation to the candela as
- 1 lm = 1 cd·sr.
A full sphere has a solid angle of 4π steradians,[2] 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 lm.[3]
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 1,000 lumens, concentrated into an area of one square metre, lights up that square metre with an illuminance of 1,000 lux. The same 1,000 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]
Lamps used for lighting are commonly labelled with their light output in lumens and, in many jurisdictions, that is required by law.
A 23 W spiral compact fluorescent lamp emits about 1,400–1,600 lm.[4][5] Many compact fluorescent lamps and other alternative light sources are labelled as being equivalent to an incandescent bulb with a specific power. Below is a table that shows typical luminous flux for common incandescent bulbs and their equivalents.
| Minimum light output (lumens) | Electrical power consumption (watts) | |||
|---|---|---|---|---|
| Incandescent | Compact fluorescent | LED | ||
| Non-halogen | Halogen | |||
| 90 | 15 | 6 | 2–3 | 1–2 |
| 200 | 25 | 3–5 | 3 | |
| 450 | 40 | 29 | 9–11 | 5–8 |
| 800 | 60 | 13–15 | 8–12 | |
| 1,100 | 75 | 53 | 18–20 | 10–16 |
| 1,600 | 100 | 72 | 24–28 | 14–17 |
| 2,400 | 150 | 30–52 | 24–30[9] | |
| 3,100 | 200 | 49–75 | 32[10] | |
| 4,000 | 300 | 75–100 | 40.5[11] |
On 1 September 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).[12] That change is a result of the EU’s Eco-design Directive for Energy-using Products (EuP).[13] 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.[14]
To estimate lumens from watts for various types of lamp, see luminous efficacy.
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.[15] 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.[16] 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 °C (77 °F). 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».[17]
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.[18]
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.
SI photometric units[edit]
| Quantity | Unit | Dimension | Notes | ||
|---|---|---|---|---|---|
| Name | Symbol[nb 1] | Name | Symbol | Symbol[nb 2] | |
| Luminous energy | Qv[nb 3] | lumen second | lm⋅s | T J | The lumen second is sometimes called the talbot. |
| Luminous flux, luminous power | Φv[nb 3] | lumen (= candela steradian) | lm (= cd⋅sr) | J | Luminous energy per unit time |
| Luminous intensity | Iv | candela (= lumen per steradian) | cd (= lm/sr) | J | Luminous flux per unit solid angle |
| Luminance | Lv | candela per square metre | cd/m2 (= lm/(sr⋅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 (= lumen per square metre) | lx (= lm/m2) | L−2J | Luminous flux incident on a surface |
| Luminous exitance, luminous emittance | Mv | lumen per square metre | lm/m2 | L−2J | Luminous flux emitted from a surface |
| Luminous exposure | Hv | lux second | lx⋅s | L−2T J | Time-integrated illuminance |
| Luminous energy density | ωv | lumen second per cubic metre | lm⋅s/m3 | L−3T J | |
| Luminous efficacy (of radiation) | K | lumen per watt | lm/W | M−1L−2T3J | Ratio of luminous flux to radiant flux |
| Luminous efficacy (of a source) | η[nb 3] | lumen per watt | lm/W | M−1L−2T3J | Ratio of luminous flux to power consumption |
| Luminous efficiency, luminous coefficient | V | 1 | Luminous efficacy normalized by the maximum possible efficacy | ||
| See also: SI · Photometry · Radiometry |
- ^ Standards organizations recommend that photometric quantities be denoted with a subscript «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
- ^ The symbols in this column denote dimensions; «L«, «T» and «J» are for length, time and luminous intensity respectively, not the symbols for the units litre, tesla and joule.
- ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ for luminous efficacy of a source.
See also[edit]
- André Blondel
- Brightness
- Luminous efficacy
- Lux
- Nit (unit)
Notes[edit]
- ^ The 9th edition of the SI Brochure gives cd⋅sr as the lumen expressed in terms of base units, although the steradian (sr) is itself listed as a derived unit.[1]
References[edit]
- ^ The International System of Units (SI) (PDF) (9th ed.). Bureau International des Poids et Mesures. 2019. pp. 137–138.
- ^ «Lesson introduction to solid angles». Retrieved Oct 4, 2010.
- ^ Bryant, Robert H. «Lumens, Illuminance, Foot-candles and bright shiny beads…». The LED Light. Retrieved Oct 4, 2010.
- ^
«OSRAM Dulux Energisparepærer» (PDF). Osram.dk. Archived from the original (PDF) on March 1, 2012. Retrieved May 25, 2013. - ^
«Conventional CFLs». Energy Federation Incorporated. Archived from the original on 2008-10-14. Retrieved Dec 23, 2008. - ^ «Learn About Light Output : ENERGY STAR». Energystar.gov. Retrieved 2012-07-15.
- ^ «LED Light Bulb Buying Guide». The Lightbulb Company. 11 August 2016. Retrieved 16 November 2017.
- ^ «Halogen lamps». www.westinghouse.com. Westinghouse. Retrieved 10 March 2020.
- ^ one example has been found, at URL: https://www.amazon.com/PacLights-Ultra150-Performance-Equivalent-Replacement/dp/B00F9CM49Y
- ^ Philips Luxeon CoB emitters, specifically LHC1-4090-1208 datasheet http://www.philipslumileds.com/uploads/419/DS115-pdf
- ^ Philips Luxeon CoB emitters, specifically LHC1-4090-1211 datasheet http://www.philipslumileds.com/uploads/419/DS115-pdf
- ^ «Lighting now labelled in lumens». England: National Physical Laboratory. Retrieved March 10, 2012.
- ^ «Ecodesign for energy-using appliances». Summaries of EU legislation. the EU institutions. Feb 2, 2010. Retrieved March 10, 2012.
- ^ «Energy-saving light bulbs: how to read the packaging». European Commission. Archived from the original on 28 June 2013. Retrieved March 10, 2012.
- ^ «ANSI lumen article». PC Magazine Encyclopedia. Retrieved Dec 20, 2006.
- ^ «Projector Guide». CPILive.net. February 2004. Archived from the original on September 3, 2006. Retrieved Dec 20, 2006.
- ^ «ANSI method of light output measurement». 1993. Archived from the original (doc) on February 26, 2012. Retrieved Jan 15, 2008.
- ^ «Sony G70 Brochure» (PDF).
External links[edit]
- International Lighting Vocabulary 2nd Edition (online searchable version of international standard CIE S 017:2020
люмен
Люмен
Лю́мен (русское обозначение: лм; международное: lm) — единица измерения светового потока в Международной системе единиц (СИ), является световой величиной.
Один люмен равен световому потоку, испускаемому точечным изотропным источником, c силой света, равной одной канделе, в телесный угол величиной в один стерадиан:.
люмен
( лат. lumen свет) единица светового потока в международной системе единиц (си), равная световому потоку, испускаемому точечным источником в телесном угле 1 стерадиан при силе света 1 кандела; сокр. обозначения: лм, 1т.
люмен
[единица светового потока в международной системе единиц (си), равная световому потоку, испускаемому точечным источником в телесном угле 1 стерадиан при силе света 1 кандела; сокр. обозначения: лм, 1т.
люмен
л`юмен, -а, р. мн. -ов, счетн. ф. л`юмен
люмен
(от лат. lumen — свет), единица светового потока СИ; обозначается лм. 1 лм — световой поток, испускаемый точечным источником в телесном угле 1 ср при силе света 1 кандела.
люмен
(от латинского lumen — свет), единица светового потока в Международной системе единиц. Сокращённое обозначение: русское лм , международное lm. 1 Л. — световой поток, испускаемый точечным изотропным источником в телесном угле 1 стер при силе света в 1 свечу .
люмен
люмен, -а, р. мн. -ов, счетн. ф. люмен
люмен
единица измерения светового потока в СИ
По сравнению с проектором РЕ5120, моделью-предшественницей, W100 обладает повышенным уровнем яркости — 1300 люмен (что дает более четкую картинку в незатемненной комнате), и возросшим до 2500:1 коэффициентом контрастности, что позволяет воспроизводить на экране более детализированное и объемное изображение в условиях полностью затемненного помещения.
Напротив, через проход, располагалась ниша Матиаса; люмен рядом с ней был погашен, сам сосед повернулся спиной, но по его напряженной позе было понятно, что он не спит.