What is LED? What is LED? LED = Light emitting diode that will emit lights when it is given electricity A light-emitting diode (LED) chip is a two-lead semiconductor light source. It is a basic p/n-junction diode which emits light when activated.
LED application What is low power LED? Low power LED is used for indication such as indicator lamp in electronic equipment etc (power is less than 0.10 watts) What is high power LED? High power LED is used for lighting purposes (power is 1 watt & above) Uses multiple high power LED inside a lamp fixture housing can create very high power LED lighting
LED material Why LED has many color type? The color of an LED depend on the LED s material Is there any LED material that can produce white light? NO! The colour of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductor s material.
White LED PRODUCING WHITE LIGHT LED How to produce white light LED? 1. By combining Blue & Yellow lights by using Blue LED chip with Phosphor coating on top of it 2. By combining Red, Green & Blue lights at the same time by installing three numbers of RGB LED inside a lamp housing & switch it on together at the same time White light can be produced by combining blue & yellow light wavelength White light can be produced by combining Red, Green & Blue light wavelength
LED chips for high power lighting What kind of LED chips are used for high power LED lighting? 1. SMD type of LED we have to install many SMD chips inside a lamp housing LED BULB LED BAYLIGHT LED FLOODLIGHT 2. COB type of LED There are a lot of LED chips casted together inside a COB LED So no need to install a lot of COB LED inside a lamp housing It needs only 2-wires to power the COB LED LED FLOODLIGHT LED TUBE LED STREETLIGHT LED high power lamp with SMD LED chips need a lot of SMD LED chip inside one lamp LED DOWNLIGHT LED STREETLIGHT LED BAYLIGHT LED high power lamp with COB LED chip no need a lot of SMD LED chip inside one lamp
Voltage vs Current of an LED Are various type of LED chip need to be driven by the same voltage? No Different type of LED chip (by color) must be driven with different kind of voltage NOTE: LED must be driven by a DC (direct current) electricity
What happens if the LED is given higher current? The light output will increase (much brighter) LED is given higher current
What happen if LED is given higher current? The LED material temperature will increase Led temperature increase
What happens if the LED material temperature rises? The light output will decrease after sometime The LED lifetime become shorter LED light output drops
LED is given higher current in long run What happens if LED is given higher current? In the long run the LED s luminous efficacy will drop (become dimmer)
Lifetime of an LED What happens if LED material temperature increase? The LED lifetime become shorter NOTE: The environment temperature of the location where the LED is installed also affecting the LED The higher the environment temperature the shorter the LED lifetime
What kind of parts inside an LED lighting that can improve the LED lifetime? 1. Driver 2. Heat sink Important parts of LED lighting
LED driver What is LED driver? LED driver is an electrical device which regulates the power to an LED or a string of LED So the current & voltage output controlled by the driver can always matched the electrical characteristic of the LED An LED driver is an electrical device which regulates the power to an LED or a string (or strings) of LEDs. An LED driver responds to the changing needs of the LED, or LED circuit, by providing a constant quantity of power to the LED as its electrical properties change with temperature. An LED driver is a self-contained power supply which has outputs that are matched to the electrical characteristics of the LED or LEDs.
LED heatsink What is heat sink? Heat sink must be able to dissipate heat in three way (conduction Convection Radiation) Heat sinks are an important part of LED lighting because they provide the path for heat to travel from the LED light source to outside elements. Heat sinks are able to dissipate power in three ways: Conduction (heat transfer from a solid to a solid) Convection (heat transfer from a solid to a moving fluid, air in most cases) Or Radiation (heat transfer from two bodies at different temperatures through thermal radiation).
Common lighting parameter Common lighting parameter! 13. Ingress protection : IP-65
What is total lumen? Total lumen is the total amount of light comes out of a light source (eg. Lamp) Common lighting parameter
What is luminous efficacy? Luminous efficacy is the efficiency of a lamp we can find it by dividing the total lumen output of a lamp in lumen with the power of the lamp in watt with the lamp then we can see the efficiency of the lamp Nowadays LED lighting companies have already achieve their LED lamp luminous efficacy up to 140 lumens/watt Common lighting parameter
What is pupil lumen? With an example shown in this page we can see with our own eyes THE BRIGHTNESS OF THE HIGH PRESSURE SODIUM LIGHT IS THE SAME AS THE LED BRIGHTNESS! But the lux meter shown differently! Common lighting parameter In fact Our eyes work differently at day time & night time: At day time Our eyes use the CONES to process the light and convert it into the shape that we can see this vision is called PHOTOPIC vision. At night time or in the dark Our eyes use the RODS to process the light. Our eyes become very sensitive and the colour that can be seen by our eyes have a tendency to be shifted to black & white colour this vision is called SCOTOPIC vision. With a lux-meter High pressure sodium lamp output is 28 lumens shown in the luxmeter With a lux-meter LED lamp output is only 12 lumens shown in the lux-meter BUT IN OUR EYES THE BRIGHTNESS OF THE HIGH PRESSURE SODIUM LIGHT IS THE SAME AS THE LED BRIGHTNESS! With The S/P ratio The correction is done 1. The High pressure sodium output becomes only 20 lux 2. The LED output becomes 21.6 lux
Common lighting parameter What is pupil lumen? An S/P-ratio was developed by Lawrence Berkeley Laboratory Then by using this S/Pratio to correct the lumen result of a lux meter we can find the lumen lamp s brightness as seen by human eyes!
What is Correlated Color temperature CCT? It is the brightness of light measured by the color identification Warm white = 2700K 3000K Natural light = 3000K 4500K Daylight = 4500K 6500K Cool white = 6500K & above Above 7500K is already BLUE Common lighting parameter
What is Color rendering index CRI? CRI is a quantitative measure of the ability of a lamp to reveal the colour of various objects faithfully in comparison with an ideal or natural light source (from the sun) the higher the CRI value of a lamp the more real the colour of the object we can see Common lighting parameter
What is beam angle? A beam angle is a measurement of how the light is distributed out of a lamp The shorter the beam angle of a lamp the higher the lumen s intensity of the lamp The bigger the beam angle of a lamp the lower the lumen s intensity of the lamp Common lighting parameter
What is E39 or E40 lamp threaded connection? Common lighting parameter
Common lighting parameter What is Total Harmonic Distortion THD? The operation of a ballast or a driver of a certain type of lamp can create harmonic (distortion of current) at the AC electricity waveform It will create a slight problem in the distribution electrical cable etc. NOTE: Incandescent lamp is not creating THD!
Common lighting parameter What is Power factor of a lamp? The operation of a ballast or a driver of a certain type of lamp can create an additional % of increasing power So the power factor of this type of lamp is below 1 NOTE: Incandescent lamp power factor = 1!
What is ingress protection IP? The ingress protection classifies the degrees of protection against both solids and liquids in an electrical enclosures/housing of a lamp. Common lighting parameter
Common lighting parameter What is ROHS? RoHS stands for the Restriction of the Use of Certain Hazardous Substances in Electrical and Electronic Equipment. The RoHS Directive which bans the placing on the EU market of new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants.