The History of LED
Over 30 years, Light Emitting Diode's (LEDs) have been used in various areas of industrial systems, hi-fi equipment, car lights or advertising. In the course of recent years, the white LED luminous efficacy has drastically increased and enabled the commercialisation of LED for residential and commercial use. This trend will continue to rise in the future, with the importance of these advancements recognising the past effort of Nobel Prize Winners Isam u Akasaki, Hiroshi Amano and Shuji Nakamura for the invention of blue light emitting diodes (LEDs).
The Basics of LED
Light emitting Diodes's (LEDs) are solid light bulbs and the latest technology in energy efficency lighting. They are sustainable and environmentally friendly substitutions for traditional light bulbs therefore are designed in a way to address the directional limitation by using diffuser lenses and reflectors to disperse the light more like an incandescent bulb.
The Breakdown of an LED Bulb
Leds are built with chip technology and use an electrical component (a diode) to flow energy between two conductive materials in a particular way that emits high levels of energy. This created energy is then built to a level that cannot be contained within the two materials and ultimately is released through the use of a semi conductor chip (a device used to control energy flow). This release creates light.
When you take a cross sectional view of a light bulb, you will find the following components:
1. OPTICAL LED COMPONENTS – when light travels from one point to another and reaches a particular surface, several interactions are possible. For lighting, we are particularly interested in reflection, transmission, refraction and absorption involved with light interacting with the primary and secondary casings of an LED bulb.
• REFLECTION. The reflection of light off a particular surface is what determines the direction at which light travels. These surfaces can be rough (sending light in many directions, i.e. diffused) or smooth (sending light out at a 90 degree angle). For example, please find below an example of diffuse and specular reflection.
• TRANSMISSION. Transmission works in a similar fashion to reflection, but concerns the passing through of light rather than reflection.
• REFRACTION. When light passes from one material to another it changes the direction in which light travels. This is a result of change in the speed at which light is traveling and typically bends away from the normal setting where light originated. For example when when you look at an object in water, the immersed section of the object in question usually looks bent. This is the concept refraction.
• ABSORPTION. Absorption refers to the energy intake of the case by the energy being produced inside of the bulb. If the light wave of a certain frequency strikes a surface with the same frequency, energy will be absorbed ultimately producing heat. This heat is what we usually feel when we touch a traditional light bulb after it has been turned on for prolonged periods of time.
In summary, LED optics are used to shape the beam of light and can be primarily lenses mounted directly on the LED or secondary optics placed above the LED packages, such as a bulb casing.
2. ELECTRICAL LED COMPONENTS - the primary electrical components of an LED bulb are the LED chips and the driver electronics.
• LIGHT EMITTING DIODE. An LED is a device that emits light when electrically influenced. Similar to any electronic component, LEDs (i.e. the yellow dots on the picture displayed to the right) also have electrical parameters that need to be taken into consideration when designed into a system. For example, luminous flux, colour, reliability, etc.
• DRIVER. Driver electronics are combined in circuitry systems that define the basic limits of bulb efficiency and power factor correction by taking high voltage AC input current and converting it to a low voltage DC current. The driver is one of the key components in an LED bulb, as determines the overall reliability and durability of the bulb.
3.THERMAL LED COMPONENTS – LEDs produce a vast amount of supplied energy through the use of heat and, as a result, the thermal systems are used to manage the proportion of electrical energy that is dissipated. The incorrect management of this heat can have adverse effects on performance and reliability, negatively affecting the light output of LEDs. The following components are typically used:
• THERMAL INTERFACE LAYER. The mechanical surfaces of the printed circuit board (PCB) are not polished, which results in many air pockets between the surfaces. As air is a bad heat conductor, the air pockets increase thermal resistance of the interface. Interface materials like thermal grease or tape are commonly used to fill these pockets to control heat.
• HEAT SINK. The heat sink is used to disperse heat to an outside medium such as air. The design of the heat sink heavily influences the airflow condition of an LED bulb, for which the heat sink fins can be manufactured in various dimensions to create desired effects.
Benefits of LED
LED has a variety of advantages over other sources of light.
• Longer Lasting – Traditional incandescent light typically have a lifespan for 1000 hours. LED bulbs can last up to 15 to 35 times longer than this.
• Durable – since LEDs do not have a filament (i.e. the thread like wire in a bulb), they are not damaged under circumstances when a regular incandescent bulb could be broken. Due to the solidness of LED bulbs, they hold up well to jarring and bumping.
• Cool Temperature– Common incandescent bulbs tend to get hot and contribute to heat build-‐up in a room. LEDs prevent this heat build-‐up.
• Mercury Free – no mercury is used during the manufacturing of LEDs
• More Efficient – LEDs typically use a fraction of the electricity required to produce light than incandescent or CFL light bulbs. LED bulbs save electricity and save money on replacement costs since LED bulbs last so long. In the attached table, you find the bulb running cost comparison for one year
|Bulb Running Cost (810 Lumen) 1 year||LED||Traditional|
|Hours of light per year (4h x 365 days)||1,460||1,460|
|Average Cost Per Watt in 2013 (€)||0.0002||0.0002|
|Input Power (Watt)||10||60|
|Running Cost (€)*||2.92||17.52|
|Total Savings Using LED (€)||14.6|
*Equation for running cost = hours x cost x wattage
Based on 4 hours of usage a day for 365 days, the above table demonstrates the savings in overall electricity bill from using Ecobelle’s 10W, 810 Lumen, bulb instead of an equivalent traditional bulb of 60W.
• Light for remote areas and portable generators – the lower power requirement of LEDs provides more practical lighting solutions for modern day technologies. For example, using solar panels becomes more practical and less expensive than running an electric line or using a generator for lighting in remote or off grid areas. LED lighting is also ideal for when using generators as backup power in the case of emergencies.
In summary, LEDS use less energy and last longer than halogen, incandescent and CFL lights -‐ meaning LED lights ultimately provide significant savings on your power bills.
The pictures on the box
If your home is equipped with dimmable lighting appliances you will be required to use LED bulbs that have a dimmable function in order to have the same dimmable effects throughout your home.
You can use dimmable bulbs in:
Non-dimmable bulbs have to be used in non-‐dimmable lighting appliances. If you use a non-‐dimmable bulb in a dimmable lighting appliance you TAKE THE RISK of damaging the LED bulbs.
LED bulbs are designed to replace existing light bulbs, which means they match all current existing bulb base/cap types. Please find below examples of the most common bulb caps:
Correlated Colour Temperature (CCT/Kelvin)
CCT is the measure used to describe the relative colour appearance of a white light source. CCT indicates whether a light source appears more yellow/gold/orange or more blue in terms of available shades of white. CCT is given in kelvins (unit of absolute temperature), where 2700K, i.e. warm light, typically provide the most comforting of light source for the human eye.
The indication illustrated on the box measures the consumption of electrical power of the LED bulb, which is measured in watts.
A lumen is a measurement of the quantity of light spread over a square foot of surface. Lumens are also the most common used metric when comparing the brightness of any bulb.
Colour Rendering Index (CRI)
CRI represents the quality of light and its faithfulness to render colours correctly, that is, to enable us to perceive colours, as we know them. LED bulb CRI ratings typically range from 70 to 80 for personal use, with all Ecobelle’s bulbs reporting CRIs of over 80.
The indication illustrated on the box measures required volts of you have at home. For example, if at home you have a system running on 220-‐240 volts; please check the label on the box and the printing on the bulb.
The finish of a bulb refers to colour of the material used on the outside of the bulb. For example, opaline resembles a milky white colour.
The years label located on the Ecobelle boxes indicates the lifespan of the LED bulb based on the assumption of being used for 4 hours a day.
Choosing the right LED light
Choosing the right LED light for the appropriate setting can be confusing at first. When choosing an LED bulb, Ecobelle suggest you focus on the following:
• Required Wattage – be aware of the equivalent wattage for the bulb you are looking to replace. For example, please find below a table that represents the equivalent comparisons when trying to replace traditional bulbs with LEDs.
|Bulb Shape||Traditional Incandescent Bulb||Ecobelle LED Bulb|
• Required base type – please be cautious of the bulb type that your appliance requires. The following bulb base types are:
• Choose between dimmable and non-‐dimmable LED bulbs as explained above
Intended use of Ecobelle LED Bulbs
LED bulbs are eletronical devices that need to be used properly. Improper use of these bulbs includes:
• Using bulb in outdoor fixtures that are surrounded by a high degree of humidity
• Using the wrong voltage bulb in the wrong appliance
• Using non-‐dimmable bulbs in dimmable lighting appliances
Remember, LED bulbs are built to fit the voltage declared by your power providers (in Italy, for example, 220-‐240V). Please bear in mind that sudden changes in voltage can cause serious damage to your devices. We advise that you monitor this situation.
To learn more about Ecobelle’s product range and their ideal uses, please click here