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Did You Really Know LED? and Why Not Choose Norming?
2017-01-05

LED is abbreviation of light-emitting diode. It is a solid-state semiconductor device that converts electrical energy directly into light. On its most basic level, the semiconductor is comprised of two regions. The p-region contains positive electrical charges while the n-region contains negative electrical charges. When voltage is applied and current begins to flow, the electrons move across the n region into the p region. The process of an electron moving through the p-n junction releases energy. The dispersion of this energy produces photons with visible wavelengths. This effect is called electroluminescence.

LEDs are used as indicator lamps in many devices, and are increasingly used for lighting. Introduced as a practical electronic component in 1962, early LEDs emitted low-intensity red light, but modern versions are available across the visible, ultraviolet and infrared wavelengths, with very high brightness.


Terminology


- Lumen(Im) – The international (SI) unit of luminous flux or quantity of light and equals the amount of light that is spread over a square foot of surface by one candle power when all parts of the surface are exactly one foot from the light source. For example, a dinner candle provides about 12 lumens. A 60-Watt soft white incandescent lamp provides 720 lumens.
- Watt(W) – The unit of electrical power as used by an electrical device during its operation. Many lamps come with rating in watts to indicate their power consumption. A light source with a higher lumen per watt value is more efficient.
- Efficacy (lumen/watt) – The luminous efficiency of a light source to convert electricity energy to light energy which is expressed in lumen output per unit power input.
- Colour Rendering Index (CRI) – The calculated rendered colour of an object. The higher the CRI (based upon a 0-100 scale), the more natural the colours appear. Natural outdoor light has a CRI of 100. Common lighting sources have a large range of CRI.
- Color Temperature (K) – A black-body radiator will have a different colour when it is heated up to different temperatures. The temperature at which the heated black-body radiator matches the colour of the light source is the colour temperature of the light source, usually specified in Kelvin (K).

Comparison of Conventional Light Sources

Light Sources Advantages Disadvantages
High Pressure Sodium Lamp efficient Transient, extremely inefficient, light loss
Incandescent Lamp Good colour rendering, very cheap Transient, extremely inefficient, light loss
Tubular Fluorescent Lamp Cheap, efficient Emit electromagnetic  radiation, emit flickering light, contain toxic heavy metals, incapable of working in cold environment, long warm up time, incapable of dimming, light loss
Compact Fluorescent Lamp efficient Emit electromagnetic radiation, contains toxic heavy metals, incapable of working in cold environment, light loss, long warm up time, relatively expensive
Halogen Lamp Good colour rendering, narrow spot light Transient, extremely inefficient
Each kind of lamps has its disadvantages respectively, hence the need for the variety of lamps.

Analysis of LED

Advantages
- Super lifespan Last at least 50 times longer than incandescent bulb, there is no need to replace the light source, reducing or even eliminating ongoing maintenance costs and periodic re-lamping expenses
- Extremely low running cost Available up to 208 lm/W, up to 90% of electricity saving over against incandescent bulb
- Inherently rugged No filament of fragile glass to break, vibration and impact proof
- Cold light source No electromagnetic radiations emitting, do not heat up the surroundings
- High-quality light   No compromise between efficacy and CRI
- Directional No wasted light, any pattern possible
- Environmental friendly Contain no mercury, lead or other heavy metals
- Instant on No flickering or warm up period as reaching full brightness in nanoseconds
- Increased safety Require low voltage (12-24VDC) power supply
- Ideal for low temperatures No issues starting in cold environment

The only disadvantage of LED is the relatively high initial cost. However, the price difference can be offset by extremely low running cost. Moreover, huge amount can be saved on the total cost of ownership (TCO).

Electricity Charge Comparison

Light Sources Wattage Quantity Total Wattage Minutely Charge Hourly Charge Daily Charge Monthly Charge Yearly Charge
50-watt Halogen 50 200 10,000 HK$0.2012 HK$12.07 HK$289.68 HK$8,690.40 HK$105,733.20
Corresponding LED lamp 6 200 1,200 HK$0.0241 HK$1.45 HK$34.76 HK$1,042.85 HK$12,687.98
T5 Tubular Fluorescent 28 200 5,600 HK$0.1127 HK$6.76 HK$162.22 HK$4,866.62 HK$59,210.59
Corresponding LED tubular 15 200 3,000 HK$0.0604 HK$3.62 HK$86.90 HK$4,866.62 HK$31,719.96
35-Watt Halogen 35 200 7,000 HK$0.1408 HK$8.45 HK$202.78 HK$2,607.12 HK$74,013.24
Corresponding LED lamp 3 200 600 HK$0.0121 HK$0.72 HK$17.38 HK$6,083.28 HK$6,343.99
Compact Fluorescent 26 200 5,200 HK$0.1046 HK$5.28 HK$150.63 HK$521.42 HK$54,981.26
Corresponding LED lamp 12 200 2,400 HK$0.0483 HK$2.90 HK$69.52 HK$4,519.01 HK$25,375.97
Metal Halide 50 200 10,000 HK$0.2012 HK$12.07 HK$289.68 HK$8690.4 HK$105,733.20
Corresponding LED lamp 24 200 4,800 HK$0.0966 HK$5.79 HK$139.05 HK$4,171.39 HK$50,751.94
Remark: the above calculation is based on the electricity tariff of HK$1.207/unit, “Unit” means one Kilowatt-hour (kWh) of electricity.

Specification Comparison

Light Sources Efficacy (lm/W) Life (hours) CRI (Ra) Colour Temperature (K)
INCANDESCENT 12 1,000 100 2,000/3,000
HALOGEN – line voltage 17 2,000 100 3,000
HALOGEN- low voltage 21 2,000 100 3,000
COMPACT FLUORESCENT – integrated electronics 69 6,000 80-89 2,700-6,500
COMPACT FLUORESCENT – external electronics 78 6,000 80-89 2,700-6,500
TUBULAR FLUORESCENT – standard light 62 10,000 60-69 2,900-6,500
TUBULAR FLUORESCENT – extra light 77 10,000 80-89 2,700-6,500
TUBULAR FLUORESCENT – high efficacy 94 10,000 80-89 2,700-6,500
HIGH PRESSURE SODIUM – standard light 102 12,000/25,000 80 2,200
HIGH PRESSURE SODIUM – comfort light 72 12,000/25,000 70 2,200
HIGH PRESSURE SODIUM – white light 30 12,000/25,000 50 2,900
MEATAL HALIDE 72-108 6,000/8,000 65-90 3,000-5,600
MERCURY VAPOR 36-60 5,000/10,000 50-60 3,500-4,200
Luminux ® LED 74-132 100,000 80-92 2,600-10,000

Why Norming LED Lamps

Norming LED Lamps Other LED Lamps
Built-in constant-current ‘Power Factory’ – regulate the drive current in order to optimize the lumen maintenance and maximize the lifespan Rely on external adapter to feature constant-current or even worse adapter which is featureless
Dedicated constant-voltage LED driver – regulate the voltage of direct-current power in order to External adapter – supply direct-current power of variable voltage to cause fluctuation on the colour
preserve the colour temperature of light and the working temperature of LED chips, facilitate the dimming of LED lamps and simplify the multi-lamp installation by connecting in parallel mode temperature of light and the working temperature of LED chips, fail in dimming and connecting in parallel mode
Built-in Working Temperature Control System – reduce the drive current automatically once the working temperature have reached the abnormal level in order to avoid overheating which can shorten the lifespan No protection at all – burn out easily due to the frequent overheating
Aluminium-core printed circuit board – conduct the heat from the LED chips to the heat sink most efficiently Ordinary fiber-core printed circuit board – conduct the heat inefficiently heat dissipation to the high power LED
Dynamic Airflow Heat Sink Design – dissipate the heat most efficiently in order to minimize the lumen depreciation of LED chips Typical heat sink design – the luminosity of lamps drop rapidly due to the inefficient heat dissipation to the high power LED
CREE LED chips – adopt LED chips from the US-based and industry-leading manufacturer in order to ensure the optimum efficacy, luminosity and reliability China-made and Taiwan-made LED chips – inefficient, dim light emitting and unreliable
Italy-made core – solder the LED chips and electronics by automated machinery in order to secure the best quality of fabrication China-made core – colder the LED chips and electronics manually with poor quality of fabrication
One year warranty – give customers the assurances on the reliability of lamps No warranty – customers get no assurance to the lamps
Unique 9X3watt extra-high power LED lamps – require the  most sophisticated technology among the production-ready LED lamps 3X3-watt is the highest power of production-ready LED lamps which require low technology only
Dimming available – convenience and increased design flexibility Incapable of dimming
Various beam angles available (15°- 80°) – suitable for most environment Fixed beam angle – limited application
High CRI of 80 – render the colours of various objects faithfully CRI below 70 – render the colours of various objects inaccurately

Strength of Cree LED chips

Steady and enduring luminous flux output, greater than 70% of initial intensity after 50,000hours of operation
Supreme efficacy of 208 lm/W, Record high of the industry
Industry-highest CRI of 92
Maximum electric current of 1,000 mA
High Tolerance to junction temperature, up to 150°C
High tolerance to humidity, up to 85%
Broad colour temperature spectrum, 2,600K-10,000k available
RoHS-compliant
Covered by a glass lens for optimum light transmission

 

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