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Topic: Luminous efficiency

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Luminous efficacy

Luminous flux

Lumen (unit)

Candela

Luminance

Lux

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	Luminous intensity (Site not responding. Last check: 2007-10-15)
		Luminous intensity is a measure of the energy emitted by a light source in a particular direction.
		In 1881, Jules Violle proposed the Violle as a unit of luminous intensity, and it was notable as the first unit of light intensity that did not depend on the properties of a particular lamp.
		It is worth noting that luminous intensity and other derived quantities are not objective physical quantity but depends on the physiology of the human eye, especially its sensitivity to light of different wavelengths.
	www.tocatch.info /en/Luminous_intensity.htm (170 words)

	Candela
		Historically, the engineers' unit of power, the watt, has been separated from the unit of luminous intensity, which is also a form of power, because the eye has a varying sensitivity over the visual spectrum, being relatively insensitive to blue and to red light.
		Luminous emission is not the same as the perceived brightness of the source when you look at it.
		The luminous intensity of a "white" light source is defined by multiplying the watts emitted at each wavelength by the efficiency of that wavelength in exciting the eye, relative to the efficiency at 555 nm.
	www.electro-optical.com /whitepapers/candela.htm (1466 words)

	LABINO (Site not responding. Last check: 2007-10-15)
		Luminance is specified with the light strength in candela in relation to the surface that the eye perceives as being the radiating source (the reflecting surface) in m2.
		The term is thus determined by the direction in that the luminance of a surface depends on the position of the eye in relation to the object.
		In the case of UV-lighting and fluorescence, the luminance is primarily dependent on the capacity of the fluorescent material to convert fl light into visible light.
	www.labino.se /support/uvfacts/terms.html (488 words)

	Luminous efficiency - Wikipedia, the free encyclopedia
		Luminous efficiency is a measure of the proportion of the energy supplied to a lamp that is converted into light energy.
		It is calculated by dividing the lamp's luminous flux, measured in lumens, by the power consumption, measured in watts.
		See the article light bulb for the specific efficiency of various types of electric light sources.
	en.wikipedia.org /wiki/Luminous_efficiency (103 words)

	Solar Light Company - PMA2133 Luminance Probe (Site not responding. Last check: 2007-10-15)
		The photopic spectral luminous efficiency curve peaks at 555nm and it is normalized to 1 at that wavelength.
		Luminance is the luminous intensity per unit area projected in a given direction.
		Luminance is essentially the amount of visible light leaving a point on a surface in a particular direction.
	www.solar.com /pma2133.htm (156 words)

	Luminance, Illuminance, Lumens, Lux, . . . (Site not responding. Last check: 2007-10-15)
		Luminous efficiency: for a given wavelength of electromagnetic radiation, its relative ability to induce a sensation of 'light'.
		For the human eye, an efficiency of 1 was assigned to the wavelength of 555 nanometers (nm).
		Luminous intensity: the number of lumens produced per unit solid angle (in a given direction) by a point source of light.
	www.scubageek.com /articles/wwwlux.html (377 words)

	Encyclopedia: Luminosity (Site not responding. Last check: 2007-10-15)
		In general physics, luminosity (more properly called luminance) is the density of luminous intensity in a given direction.
		In physics, specifically photometry (optics), the lumen (symbol: lm) is the SI derived unit of luminous flux.
		The steradian (ste from Greek stereos, solid) is the SI derived unit of solid angle, and the 3-dimensional equivalent of the radian.
	www.nationmaster.com /encyclopedia/Luminosity (1893 words)

	Luminous Power (Site not responding. Last check: 2007-10-15)
		The lumen is the standard unit for the luminous power of a light source.
		The luminous power is the part of the power which is perceived as light by the human eye, and the figure 683 lumens/watt is based upon the sensitivity of the eye at 555 nm, the peak efficiency of the photopic (daylight) vision curve.
		The luminous efficiency is 1 at that frequency.
	www.kemt.fei.tuke.sk /Predmety/KEMT422_SPAS/_web/Hyperphysics/lumpow.html (139 words)

	Luminous Efficiency Functions at Higher Intensities - Storming Media
		Luminous efficiency was found to depend on both the technique and the reference stimulus intensity with which the measurements were taken.
		Peak luminous efficiency shifted from approximately 540nm to greater than 6OOnm with increasing intensity for all seven subjects.
		Peak luminous efficiency was constant for flicker photometry across all intensities but the function narrowed slightly at 100 foot-lamberts.
	www.stormingmedia.us /84/8433/A843324.html (140 words)

	eKATT00080 (Site not responding. Last check: 2007-10-15)
		By this we mean the efficiency, the luminous efficiency (lm/W), of a fluorescent tube and how this falls during the life of the fluorescent tube.
		Luminous efficiency- is a measurement of the efficiency of a light source and is expressed in lumen per Watt (lm/W).
		A high luminous efficiency thus means that a light source converts a lot of the energy into light.
	www.elektroskandia.se /english/T/eKATT00080.htm (1268 words)

	Spectral Luminous Efficiency for the Human Eye (Site not responding. Last check: 2007-10-15)
		Maximum sensitivity for photopic vision is at a wavelength of 555 nm (green), declining to both the longer wavelengths (yellow, orange, red) and the shorter wavelengths (blue, violet).
		The process can be observed in the field of artificial lighting, in which human beings prefer a daylight white light Color Appearance with a high level of blue when illuminance is high, but a warm white light when illuminance is low.
		Photometers (Illuminance, and Luminance Photometry) are nearly always set for phototopic vision, and the various photometric parameters are also based on the V() evaluation.
	www.zumtobelstaff.com /light-dictionary/en/Litec_enSpectral_Luminous_Efficiency_Human_Eye.html (317 words)

	Candela - Wikipedia, the free encyclopedia
		The candela (symbol: cd, Latin for candle) is one of the seven SI base units.
		It is the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 × 10
		At other frequencies, more radiant intensity is required to achieve the same luminous intensity, according to the frequency response of the human eye (called the V-lambda curve in the reference below).
	www.wikipedia.org /wiki/Candela (218 words)

	United States Patent Application: 0030151044
		Thus the luminous efficiency of the device can be improved by depositing the second well layer between the first well layer and the p-type semiconductor layer.
		Consequently, the ratio of the luminous intensity emitted by the first and second well layers is kept constant, that leads an improvement in minimizing diversity of the luminous intensity and luminous nuance between each device.
		To be less preferably, the luminous intensity ratio of the first and second well layers 308, 309 has greater diversity among the devices so that it is almost impossible to repeatedly manufacture the light emitting devices emitting white light with the desired color rendering property.
	appft1.uspto.gov /netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PG01&p=1&u=/netahtml/PTO/srchnum.html&r=1&f=G&l=50&s1="20030151044".PGNR.&OS=DN/20030151044&RS=DN/20030151044 (12832 words)

	1C: Flat Panel Displays
		Improvement of luminous efficiency from a current typical value of 1-2 m/W to 5 lm/W is the most crucial issue for PDPs to be of practical home use.
		For the standard coplanar-electrode geometry it is found that there is a trade-off between high efficiency and low operating voltages as the electrode gap, or other parameters of the upper dielectric are varied, while variation of the sustain electrode width has no significant effect on either the operating voltages or efficiency.
		Especially interest thing is that under those high-pressure condition, the efficiency increases as the sustain voltage increases unlike the low-pressure condition where the efficiency decreases as the sustain voltage increases.
	www.ee.ualberta.ca /icops2002/programtest/1C.htm (2188 words)

	Document: Optical Principles (Site not responding. Last check: 2007-10-15)
		The standard illuminant D 65 represents medium daylight conditions with the colour temperature 6500 K and is usually generated by the use of xenon lamps with filters.
		The relative visual attenuation quotient Q is the ratio of the luminous transmittance of a tinted lens for the spectral radiant power distribution of the light emitted by a traffic signal t
		Q does not therefore provide any information on the wearer's colour perception with a lens, but only indicates whether the luminance of a traffic light is more or less strongly attenuated than the ambient luminance (Q less or greater than 1).
	www.zeiss.com /4125680F0053A38D/allBySubject/FEE47C4321499FFDC1256C2C00452AAB (212 words)

	[No title] (Site not responding. Last check: 2007-10-15)
		Their averaged functions are derived with the intention that they be used to evaluate the luminous efficiency for the brightness of monochromatic lights.
		The spectral luminous efficiency function for a point source may be adequately represented by the Judd modified V(lambda) function.
		The spectral luminous efficiency functions for the brightness of a 2 ° field and a 10 ° field at photopic levels are different from the CIE V(lambda) function and are tabulated in the Technical Report.
	www.cie.co.at /publ/abst/75-88.html (206 words)

	PHOTOPIC LUMINOUS EFFICIENCY FUNCTION OF THE HUMAN RETINA
		The darkest area is the region generally described as the scotopic spectral sensitivity function or frequently the "scotopic luminous efficiency function." The heavy line enclosing the scotopic area and the lighter gray area on the right defines the photopic spectral sensitivity function or the "photopic luminous efficiency function.
		All five of the theoretical peaks in the photopic luminous efficiency function are easily observed with adequate instrumentation.
		However, the historical measurements leading to the current CIE Photopic Luminous Efficiency Standard (solid line) were acquired using instrumentation of the 1920's (with corrections suggested by Judd using instrumentation of the 1930's).
	www.4colorvision.com /files/photopiceffic.htm (1472 words)

	Clay Paky - Products
		The lamp-optical system combination provides almost double the luminous efficiency (+95%) of standard units; a result which is absolutely unique among moving mirror spotlights of this size, which means that the Mini Scan HPE has all the power necessary for longer range applications while still offering a low power consumption.
		Mini Scan HPE uses a 300 watt Osram HTI 300 lamp, with a luminous flux of 22000 lumen, an average life of 750 hours and a colour temperature of 6500° K. This extremely efficient and reliable lamp has been designed specifically for Clay Paky on the basis of professional HMI models.
		The special design of the optical system with twin lens condenser and high luminous efficiency mirror ball, combined with the use of high quality components, means that, even at maximum aperture settings, the beam from the Mini Scan HPE appears sharp and uniform over the entire illuminated surface.
	www.claypaky.it /english/products/cat1_minischpe.htm (769 words)

	Incandescent light bulb
		A fluorescent lamp, which is approximately four times more efficient (about 40%) than an incandescent lamp (about 10%), will produce one-sixth of the heat, assuming the same levels of light from both sources.
		This is one reason why fluorescent lighting is so popular in commercial spaces, as it also reduces the need for air conditioning in the summer.
		Quality halogen incandescents are closer to 15% efficiency, which although still extremely low, will allow a 60 watt bulb to provide nearly as much light (and a 75 W to provide even more) than a non-halogen 100 watt.
	www.sciencedaily.com /encyclopedia/incandescent_light_bulb (2590 words)

	Bajaj Electricals Ltd. - Luminaires BU Catalogue - (appliances, fans, lighting, luminaires, engineering and projects) (Site not responding. Last check: 2007-10-15)
		The luminous intensity distribution of a floodlight is presented in the form of a Cartesian diagram.
		the maximum luminous intensity of a double asymmetrical beam luminaire in the main plane, given at the angle relative to the perpendicular to the front of the luminaire.
		The luminous intensity may be derived from the luminous intensity diagram or from a table.
	www.bajajelectricals.com /catalog/lumcatalog/intro_area.asp (2194 words)

	Metrics for solid-state lighting (May 2005) - Features - LEDs Magazine
		Luminous efficacy of a source is the ratio of lumens (total luminous flux) to watts (total electrical power input).
		However, luminous efficacy of radiation is the ratio of luminous flux to radiant power, which is a theoretical maximum that a light source with a given spectral distribution can achieve with a 100% radiant efficiency.
		Obviously radiant efficiency cannot exceed 100%, and so the luminous efficacy cannot exceed the theoretical maximum, which is determined solely by the spectrum of the source.
	www.ledsmagazine.com /articles/features/2/5/4/1 (2139 words)

	An Investigation of Headlamp Glare, DOT HS 809 672, October 2003
		The photopic luminous efficiency function (shown in Figures I-1 and II-9 of this report) is used to determine the relative weighting for radiant power from a light source (e.g., in W) at each wavelength in order to calculate photometric quantities (e.g., luminous flux in lm, illuminance in lx, or luminous intensity in cd).
		Similarly, the scotopic luminous efficiency function characterizes the spectral sensitivity of the rod photoreceptors in the eye.
		Unlike the luminous efficiency functions shown in Figure I-1, these functions are scaled to a value of 683 lm/W at 555 nm.
	www-nrd.nhtsa.dot.gov /departments/nrd-01/GlareSpectrum/pages/8Appendix.html (354 words)

	Article on Lunar Leonid Impact Luminous Efficiency (Site not responding. Last check: 2007-10-15)
		Luminous Efficiency in Hypervelocity Impacts from the 1999 Lunar Leonids L.
		It is shown that the observational data are consistent with luminous efficiencies of 2 x 10^-3 in the wavelength range of 400-900 nm with an uncertainty of about 1 order of magnitude.
		According to our results, the luminous efficiency might vary with mass, i.e., the smaller impactors converting less kinetic energy into light and vice versa.
	iota.jhuapl.edu /lunar_leonid/lumefo04.htm (205 words)

	Photometry Optics (Site not responding. Last check: 2007-10-15)
		Similarly, the adjective "bright" can refer to a lamp which delivers a high luminous flux (measured in lumens), or to a lamp which concentrates the luminous flux it has into a very narrow beam(candlepower).
		The lumen is defined as one candela per steradian; while the candela, a base SI unit, is defined as the luminous intensity of a source of monochromatic radiation, of frequency 540 terahertz, and a radiant intensity of 1/683 watts per steradian.
		Within the visible spectrum, wavelengths are light are weighted according to a function called the "photopic spectral luminous efficiency." According to this function, 700 nm red light is only about 4% as efficient as 555 nm green light.
	www.wikiverse.org /photometry-optics (814 words)

	TN 1421, Filter Detector Syst., Photometry Colorimetry
		is the luminous efficacy defined by the CIPM to be 683 lm/W for photopic vision [11].
		Light sources used for illumination are rated in terms of the total luminous flux output, often abbreviated to luminous flux, measured in lumens.
		A second frequently used integration method is the use of an integrating sphere for averaging the output of a particular source and deriving its luminous flux by comparison to a known source in the same sphere.
	physics.nist.gov /Pubs/TN1421/filter.html (1601 words)

	Illumination
		The renaming of the time-honored luminous efficiency to "luminous efficacy" is yet another example of worthless pedanticism.
		The total luminous flux E emitted per unit area from a lambertian surface of luminance B is easily calcuated.
		If B is the luminance of the object, and B' the luminance of the image, then the luminous flux in the input is BΩdA, while the luminous flux in the output is B'Ω'dA'.
	www.du.edu /~jcalvert/optics/lumens.htm (2743 words)

	LightEmittingDiodes.org Chapter 7
		Dependence of the luminous efficiency of an AlGaInP double heterostructure LED emitting at 565 nm on the active layer thickness.
		Dependence of the luminous efficiency of an AlGaInP double heterostructure LED emitting at 565 nm on the active layer doping concentration (after Sugawara et al., 1992).
		Dependence of the luminous efficiency of an AlGaInP double heterostructure LED emitting at 565 nm on the p-type confinement layer doping concentration (after Sugawara et al., 1992).
	www.ecse.rpi.edu /~schubert/Light-Emitting-Diodes-dot-org/chap07/chap07.htm (435 words)

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