V is the voltage.F is positive.I represents current.R stands for reverse.WL represents the wavelength.
So: VF forward voltage representative of the general low-power led red, yellow, orange, yellow and green of vf is 1.8-2.4v, pure green, blue, white, vf is 3.0-3.6v. IF is the forward current, low-power generally led the IF is 20mA. IR is a reverse current,
Generally in the reverse voltage below 5v measured points is less than 10uA (microamps), less than 5uA and 0uA several grades. WL is the wavelength, the wavelength of visible light have separate, different wavelengths corresponding to different colors, such as the red light is usually 615-650nm (nanometers), blue light is usually 450-475nm. Because it is a blue chip + white phosphor modulation, so no wavelengths to measure the color temperature (3000k the following yellowish. 3000k-7000k is white, 7000k more blue).
LED's Vf values mean? It's the size of the LED have any effect?
vf is the forward voltage of the meaning, but not necessarily larger forward voltage, forward current is greater. You see as long as the recognition of low-power led book value of the above will have a vf, If there is a value, regardless of how much value is vf, (red, yellow, green, orange usually 1.8v-2.4v, white, blue, green generally 3.0v-3.6v). If is 20mA. The two are complementary. Example, two white, one is 3.0v, 20mA, one is 3.4v, 20mA, meaning that the first one lamp, you give it 3.0v voltage, the current flowing through it is normal rated current of 20mA, but the first two lights, you give it 3.4v voltage, the current flowing through it is 20mA.Where Vf and If there is no proportional; but one yellow and one white light ratio, such as the yellow light of the voltage is 2.0v, white lamp voltage is 3.3v, 2.0v Fengyun yellow in the voltage and this pieces of white light in 3.3v voltage current flowing through them is the same, are 20mA, Vf and If here is not proportional. Therefore, only specifically refers to the case of lamps with a Vf and If is absolutely proportional. Whether you use when Vf is, so long as control flow all the lamp current of 20mA on ok
LED basic terminology
Luminous flux (lm): the amount of light to emit visible light per second sum. For example, a 100-watt (w) for bulb produces 1500lm, a 40-watt (w), can produce 3500lm lamp luminous flux. ◇ luminous intensity (cd): in the unit solid angle of light emitted flux, which is the light flux emitted by the selected direction in the space density distribution. Intensity unit is Cantera (cd), also known as candlelight. Such as: 1 issued within a unit solid angle lumens of light called a Cantera (1cd).◇ Brightness: light-emitting diode is a light-emitting device, luminance refers to the unit area of illumination, the unit is: cd / square meter, standard LED drive current of 20mA.
Color Temperature (k): the absolute temperature (k = ℃ +273.15) K to represent, about a black body heating, the temperature rose to a certain extent, the color gradually from dark red - light red - orange - yellow - yellow - white - blue - changes in blue. When a light source with the same bold colors, we will be bold when the absolute temperature as the light source's color temperature. Such as: When the bold dark red showing the heating temperature is about 550 ℃, the color temperature of 823K.
Luminous efficiency (lm / w): the luminous flux emitted divided by the light source the power consumed. It is an important indicator to measure light energy.Color (ra): light color rendering of the object itself is called the degree of color. That is, the degree of color fidelity. International Commission on Illumination CIE color rendering index of the sun set at 100. Various types of color rendering index varies. Such as: incandescent ra ≥ 90, fluorescent ra = 60 ∽ 90.
Viewing Angle: Angle X-axis points (left, right) Y-axis (up, down) when the center axis 1 of the brightness, the brightness of left and right or up and down the shaft 1 / 2, the angle of viewing angle; example 70 ° to Viewing angle refers to the down or left from the center of 35 °.
Wavelength: two LED wavelengths of light emitted, usually red wavelength 620-660nm, pure green, 520-530nm, the blue 470-480nm, Yellow 580-890nm, yellow 550-570nm, see chromaticity diagram, different given wavelength of light of different colors; mixing two colors of light are also different.
Quaternary: refers to the ALInGaP four chemical elements produced by the light-emitting diodes, can issue yellow / yellow / orange / red (wavelength 550-630nm) between the light with high brightness, low attenuation characteristics for outdoor light-emitting diodes of the current mainstream products.
Pure Green / yellow: the traditional green LED is yellow-based, wavelengths from 550-570nm, low price, low brightness, decay fast, manufacturing company in 1994, Japan and Asia to create a pure green (wavelength 520-530nm) price high, high brightness, decay slowly, widely used in outdoor display, these two products have significant differences, the design must be clearly distinguished.
Single / dual color / full color: primary colors of red / green / blue; if a pixel tube containing these three light-emitting diodes are referred to as full-color display; if only as two-color red + green screen, if only one color such as red or yellow is called monochrome display, monochrome text display to play the content-based, dual-color places text + graphics + animation-based, full-color video broadcast places signal-based.
Life: refers to the initial value of brightness light-emitting diodes in half the time, has become a half-life, different chips used in different environments have different life.
Intensity decay curves: a variety of chips under certain conditions (temperature, current) and time intensity curve; this curve can truly understand the characteristics of the chip is good or bad.
Chip / single lamp / pixel pipes: two LED semiconductor material, said light emitting element chip into a chip package can be lit with the smallest unit, said single lamp; many small lamp assembly irrigation package into a large pieces of plastic pipe Cover with a pixel pipe.
Point diameter: mean pixel tube diameter.
Pitch: refers to the two adjacent pixels of the distance between the control center, standard distance between the distinguished point of light = light point diameter × 1.25.
Visible distance: refers to the distance can be clearly seen in this display shows the contents of the body, this word from the text and display related to the high, simple quick calculation formula: --- last visible distance: 50 × high character height (m) --- farthest visual distance: 200 words, high altitude (m)
Automatically adjust the brightness: brightness light-emitting diodes as the strength of the environment, but also for their own strength of brightness adjustment, generally to reduce the current approach to achieve the purpose of reducing the brightness.
Point Density: refers to the number of pixels per square tube.
Operating temperature: you can display the normal minimum temperature and maximum use temperature.
LED light source compared with conventional light sources
Type of light source efficiency (lm / w) Color Temperature (k) Average Life (hours)Incandescent bulbs 1528001000White British halogen 25 30002000-300070 whole series 8000 general fluorescentThree-color fluorescent full range 10 000 9650-250 full range of 50,000 LED lights
LED explanation of terms, and several optical conversion between
1 light intensity (brightness) What is the meaning?
A: The light intensity (brightness, I) is defined as: point source of luminous intensity in a certain direction, that is the luminous body in unit time by the amount of light emitted, also referred to as brightness, common units of candles (cd, cd), defined as an international candle made from whale oil candles burning 120 cells per hour, cold (grain) luminosity emitted by a cold frame is equal to 0.0648 g
(2) light intensity (brightness) of the unit?
A: The luminous intensity of common units of candles (cd, cd), the international standard candles (lcd) is defined as an ideal blackbody in platinum freezing point temperature (1769 ℃), the perpendicular to the blackbody (the surface area of 1m2) direction of 60 births one of the luminosity, the so-called ideal blackbody radiation rate of an object is equal to 1, the energy absorbed by the object can go all the radiation, so that the temperature has remained constant uniform international standard candles (candela) and the old standard candles (candle) of the exchange relationship To 1candela = 0.981candle
3 What is flux? Flux units?
A: The luminous flux (φ) is defined as: point source or non-point source in a unit time emitted by the energy, which can produce visual person (who can feel the radiation flux) that is known as flux. The unit of luminous flux lumen (abbreviated lm), 1 lm (lumen or lm) is defined as an international standard candles of light in the unit solid angle within the arc by flux, due to the spherical area of 4πR2, so that the luminous flux equal to one candle-class luminous flux emitted by the 1/4π, or spherical with 4π, so by definition we can see a cd lumen point source will radiate 4π lumens, that is φ (lm) = 4πI (candlelight), assuming △ Ω is a small three-dimensional arc angle, within the solid angle in △ Ω flux △ φ, then there is △ φ = △ ΩI
4 one foot candle What is the meaning?
A: A foot-candles from a candle is the light source (point source or non-point source) a feet away with the light illumination surface orthogonal, abbreviated as 1ftc (1lm/ft2, lm / ft 2), persquare feet within 1 lumen luminous flux received when the illumination, and 1ftc = 10.76lux
5 one meter candlelight What is the meaning?
A: The one meter away from a candle is a candle light source (point source or non-point source) with one meter of the surface orthogonal light illumination, known as the lux (lux, has written lx), per square kilometers feet within the luminous flux received when the illumination is a lumen (lm / m 2)
6.1lux What is the meaning?
A: Each square of the received flux of 1 lumen when the illumination
7 What is the meaning of illumination?
A: The illuminance (E) is defined as: the object to be units of the exposed area on the acceptance of the flux, or by light irradiation of the objects in the unit time per unit area on the accepted luminosity, units in meters candles or foot-candles ( ftc) that
8 illumination and brightness, What is the relationship between the distance?
A: The intensity and brightness, the distance is the relationship between: E (illumination) = I (brightness) / r2 (distance squared)
9 is the body of the illumination according to the size and what factors?
A: The body according to the luminous intensity of illumination and light and the illuminated body and the distance between the light source, but not with the body color of the illuminated surface is independent of the nature and surface area
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