Learn The Technical Specification Of LED Light

Today, lights(http://twd.com.vn/lighting) are not use for lighting but also as an art of lighting for lights player, for each location, using any type of lights, the color how it is, that depends on each person's choice. Currently, on the market, there are many different types of lights designs but few peple understand the specification of these. Understanding the specification is also important, it will be of great help us in choosing lights so that when ordering or buying, suppliers will know what you want. For large-scale projects of TWD, such as: apartments, hotels...the nees to use LEDs is large, how to choose the lights will be designed by and selected by electrical engineers. If you are an electrical engineer or you want to know more about specification of LEDs, keep reading this article, TWD will help you better understand the indicator and specification of LEDs.

Image illustrating lights' parameters

 What is luminous Flux?

Luminous flux indicates the radiant power of a beam of light emitted from a light source or another definition of luminious flux is the amount of light emitted from a light source in all directions per second.

• Luminious flux is denoted by φ or Φ_v
• The unit of luminious flux is Lumen, symbolized as Lm, we can know that the Lumen is defined by the luminious flux, created the light source that emits light intensity.

Luminious flux is used to measure amount of light emitted by an electric light, it does not count in a specific light direction, this value is usually writen on lighting products.

The formula for calculating the luminious flux: Φ_v = dQ_{v/dt (Qv: total light energy of a light source)}

_{Image of Luminious flux}

What is Illuminance?

Illuminance is used to assess the perceived light intensily.

• the formula for calculating the illiminance: Illuminance =(W x Lm/w x amount used)/ lighting are(m2)
• Formula notation: Lux=Lumens/m2

Today, illuminance standard is applied in civil lighting, office lighting, public lighting building, factory lighting.

The following are illuminance standard of natural lighting:

- Sunlight has an average illuminance ranging from 32.000 to 100.000 lx

-At the sunset or Dawn, the outdoor light is also illuminated 400lx

-Light reflected from moon will usually have an illuminance of about 1 lx

-Light from the stars has an illuminance of about 0,00005 lx

-The studios in the television station are illuminated with a illuminance of 1.000 lx

-A bright office will have an illuminance of about 400 lx.

Image of illuminance

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What is Luminance?

Everyone must have once looked at the sun or looked at a light buld, and at that time, the radiating power of the light source shines into our eyes and causes a dazzling feeling.

Luminance is derived optical quatity, determined by the intensity of light per unit area in a specific direction.

Unit of Luminance measurement: cd/m2 (candela/square meter)

The greater luminance, the better our ability to see that object. With the same distance, lower luminance will make object blurred, so we cannot see as clear as with a better luminance.

In fact, the choice of low or high luminance depends on the user's need, but some eye's problems are cause by working in poor light source, so we should choose the suitable luminance to ensure the best vision.

What is correlated color temperature (CCT)?

The unit of CCT is Kelvin (K)

CCT is a concept is drawn from Planck's radiation law. We all know that an object will glow when it is hot. Different temperatures will produce different color light, so when we look at the spectrum of a hot object, we can estimate its temperature, from which, the definition of color temperature of light appears.

in life, the types of bulds we use have a CCT of 1000K or more, the red light has CCT less than 5000K, and when the CCT is above 5000K, the light will turn blue.

Image of CCT

Currently, on the market, the most popular 3 types of LED color:

• Warm light: CCT from 2700K to 3500K
• Natural light: 4000K - 5000K
• Cool light: 5000K - 7000K

The warm yellow light bulbs are mostly used in the private dinning rooms of restaurant to creat a cozy look or in the baths to bring relaxing warmth. As for the natural light of cool light are usually installed in office areas, hotel lobbies...

What is color rendering index (CRI)? 

CRI of a light source is a measure of the indicator evaluates the color fidelity of the illuminated objects compared to an ideal light source or a natural light. CRI index is defined by International commission on illumination (CIE).

The higher CRI index, the higher the fidelity of the objects, The color rendering index usually ranges from 70 to 100. With the same light source but the CRI  of the light source is different, the reality of the object we see is also different.

Image for CRI

Commonly used CRI:

• CRI = 0: Monochromatic light: Blue, red, yellow, violet...
• CRI < 50: the color of object is completely changed, the illuminated object will be fades without realistic.
• CRI from 50 - 70: The color is slightly variable, used for ares where the color fidelity is not high: yard lights, street lights...
• CRI from 70 - 85: common light
• CRI from 85 - 95: used for special areas that need standard color separation such as: Dyeing workshops, paint processing workshops...
• CRI = 100: Daylight

What is Lighting performance?

It is the light-emitting efficiency of lights, equal to the ratio of the luminous flux and power consumed of lights. The light has high lighting performance is the light with high luminous flux and low engerny consumption. The higher lighting performance, the more economical the lights. The biggest advantage of LEDs is having high lighting performance.

The lights with lighting performance from 70-90 lumen/W, used for households, offices...

The lights with lighting performance from 110-110 lumen/W, used for large spaces such as: factories, sports grounds...

What is Lighting angle?

Lighting angle is the angle between two sides with a minimum of 50% of the strongest light intensidy in the central bright area. You can simplest identify the angle by illuminating the wall. You can easily notice the large bright area, small bright area...

With the same light source but has different lighting angle will bring different image of bright area.

There are 3 types of lighting angle:

Angle: 3⁰, 5⁰, 8⁰ are the narrow angle, they are designed to be used for remote projection with a small angle that emphasized the angle of projection such as: lighting columns, interior and exterior lighting for villas or constructions 

Angle: 10⁰, 24⁰, 38⁰ are the medium angle, used for searchlights.

Angle: 100⁰ is the large angle, the lights with 100⁰ of angle are suitable for installing in office areas, common areas of community, kitchen...

What is IP index? 

Ingress Protection (IP) is an intrusion protection index against the impact of the environment such as impact of dust, water penetration.

IP index includes 2 number. The first number refers to against solid oblects (Dust) and the second number refers to against liquids (water).

The value of the first number ranges from 0 to 6 and the value of the second number ranges from 0 to 9.