How to choice LED lights? LED will certainly become the fourth generation of lighting, its development momentum is growing, the main advantages are: energy-saving and environmental protection, long life, no stroboscopic harm to the eyes, do not attract mosquitoes.
As long as the heat dissipation design of high-power LED lamps is good enough, the life of 30-50,000 hours is not a problem.
The definition of life is: because the LED is a semiconductor component, its wafer will be affected by temperature to produce light decay, when the luminous flux of the LED is less than 30% of the initial luminous flux due to light decay, basically secondary LED lamps have no illumination significance.
That is to say, life summary, although the LED lamp can still be lit at this time, the brightness has been seriously reduced, so the heat dissipation of LED lamps is very important.
You said that the object illuminated by the LED lamp will be discolored because of the lack of a color in the spectrum, which is the wrong idea.
In a very simple sense, color TV (CRT) is not just a mixture of three basic colors (red, green, blue) to get a variety of colors.
Lighting is mainly white light LED with high power, mainly blue light chip excitation phosphor mixed with white light.
1. the color rendering index of LED is too low to cause the emitted light to reflect the true color of the object.
(The color rendering ability of the light source to object is called color rendering. The highest color rendering index Ra is 100, and the best color rendering ability.) At present, if the color rendering index of LED reaches 80-85, it is very good and can be used for indoor lighting.
2. the color temperature of LED is not good, and simple understanding can be regarded as the color of light.
If the color temperature is low, the light will be greenish and reddish, and if it is too high, it will be blue, which is not suitable for indoor lighting. Therefore, indoor lighting is a very important parameter for the color temperature of LED lamps.
LED generally defines color temperature at 2700K-4000K as warm color, 4000K-5000K as natural white, 5000K-6700K as white, warm white and natural white warmth will give people a warm, warm feeling, suitable for use in hotels, hotels, and bedrooms.
And white gives people a cool and refreshing feeling, used in the office, living room lighting more (fluorescent lamps are generally more of this kind of color temperature). The brightness is equal to a 100W energy-saving lamp, which depends on the luminous efficiency of the LED lamp (lumen/watt, lm/w). The brighter the LED lamp with the same wattage, the higher the luminous efficiency, the higher its brightness.
In addition, I really haven’t seen the brightness of 100W energy-saving lamps ^ at least our company has not produced more than 60W LED indoors, the last thing to say is to buy LED lamps should pay attention to the light efficiency, color temperature, color rendering index, light decay. The first three are the general parameters of all lamps, and the last one is the special property of LED as the semiconductor.
In addition, some people have the following misconceptions when choosing LED lights.
However, like all basic light sources, the luminous flux of LED also attenuates over time. Therefore, although the LED emission time can be very long, MTBF is not the only consideration for determining the service life.
The attenuation of LED lumens is affected by many environmental conditions such as ambient temperature, humidity, and ventilation. Lumen attenuation is also affected by control, thermal management, current levels, and many other electrical design considerations (cited above from CK Corporation, USA).
Many salesmen may provide some vague information to customers for some reason, which may lead to misleading. For example, the service life of LED is about 100,000 hours, where 100,000 hours refers to the life expectancy of the manufacturer.
As the light source of lighting, the brightness of the lamp has a gradual process of fading (such as fluorescent lamp, energy-saving lamp), which is referred to as light fading.
On application-level LED, when the light fade exceeds 50%, the human eye can obviously feel the change of brightness.
At this time, the brightness of the product is not suitable for lighting.
How to choice LED lights? Many manufacturers and engineers use low-cost LED for about three months to half a year, often find that the brightness of the LED is obviously not as bright as when it was just installed, or even nearly no because the reasons for the lack of consideration of LED light decay.
To sum up, when we purchase LED, we should pay attention to the speed of its decay rather than its time.
How to choice LED lights? The luminous angle of LED is divided into an effective angle and actual luminous angle.
The angle between the direction half of the axial intensity and the normal direction is the effective angle.
The angle of half-value angle is 2 times the angle of view (or half power angle) is the actual luminous angle.
The angle is less than half of the axial strength because the light is too weak to be effective in practical application.
So we should pay attention to the actual light-emitting angle when we choose and purchase products.
How to choice LED lights? When calculating the number of products used in the project, we should take the actual light-emitting angle as the reference value, and the effective light-emitting angle can be used as the reference value.
The brightness of LED is measured by luminous intensity.
The luminous intensity refers to the luminous intensity in the direction of normal line (to the cylindrical luminous tube refers to its axis), i.e. the luminous flux emitted by the unit solid angle, in the unit of candela (cd).
Because the luminescence intensity of general LED is small, the intensity of luminescence usually uses Candela (MCD) as a unit.
Generally speaking, the light source will radiate its luminous flux in different directions with different intensities, in a specific direction.