What is LED lights, Kelvin, Lumens, Ra?

What is LED lights and LED light sources

LED stands for Light Emitting Diodes. They have been known for a long time and used in all kinds of devices as indicators, such as in hi-fi, coffee machines, cars, household appliances, but it is only in recent years that the amount of light emitted from them has become so powerful that they can be used as light sources.

LEDs can illuminate in many different colors, but can be categorized by being able to illuminate only one color at a time. The colors that are easiest to make on LEDs are blue, yellow, green and red. The white color cannot be made with an LED directly. What the light manufacturers do is that they make a blue diode and let the light pass through a phosphor layer, which changes the blue color to white. With the three LED basic colors red, green and blue you can make all colors in the color spectrum. This is used in all color televisions, where all colors are created from these three LED primary colors. Any color is created by mixing the RGB colors at different intensity. Typically, each of these three primary colors has 256 light levels, and so the number of colors becomes 16.8 million (256x256x256).

LED Color Temperature

Color temperature is a measure of the color of the light itself. Color temperatures above 5000K are called cold colors and color temperatures below 3000K are called warm colors. The more of the red color, the warmer the light.

As an example, the old incandescent bulbs go all the way down to 2500K and the halogen bulbs a little higher or around 3000K. LEDs are available in many different colors, ranging from around 2700K, which some manufacturers call VWW (Very Warm White) and then the typical WW (Warm White), which is around 3000K and White, which can be much higher or up to 6000K .

RA (or CRI)

RA value is the ability of light to reproduce colors from the material or objects that the light falls on. The lower the RA value, the poorer the light is at reproducing colors from the material or objects that the light falls on.

An old-fashioned incandescent bulb and a halogen bulb have an RA value close to 100, which is the optimal color rendering. An incandescent bulb contains all light colors and can therefore reproduce all colors. In a color television, where all colors are formed from red, green, and blue, all colors can be created, but since these colors are all created from only the three basic LED colors, they cannot reproduce all colors that light falls on. Therefore, a white light created from these three basic LED colors will typically have a very low RA value, or as low as around 20.

Lumens

The lm or lumen tells you how much brightness comes from the light source. The greater the number, the greater the brightness. Before the LED era, one might say (perhaps a little popular) that the brightness was more or less expressed in watts.

You went to the store and bought 40 or 60 watt bulbs, which were the most common sizes. But for other purposes, you could get bulbs ranging from about 10 watts to 200 watts. Now that we have LED and high-efficiency halogen light sources, it no longer makes sense to talk about watts. The new term for light source intensity is lumens. The old 40W bulbs provided around 450 lumens, while 60W bulbs provided around 800 lumens.

LED lifetime

The lifespan of LEDs is much longer than that of old incandescent bulbs, ranging from 10 to 25 times longer. Old incandescent bulbs have a lifespan of approx. 2,000 hours, while LEDs have a lifespan of approx. 20,000-50,000 hours. However, it should be noted that the lifespan of LEDs is calculated such that when the light from the LED has decreased by 50%, this is the lifespan of the LED in question.

The lifespan of old incandescent bulbs is calculated until the bulb no longer lights up. The lifespan of LEDs is highly dependent on the cooling of the LEDs. All ODSIF lamps have a large aluminum cooling surface, which ensures that the LEDs can dissipate heat and therefore have a lifespan of 50,000 hours. What does this mean in terms of years? Well, if you use LED lights for an average of 4 hours a day, the LED light will last for 34 years. So there is a reasonable chance that a lamp will be discarded before the light from it has become unusable.

Lumens/W

lm/W indicates how much of the power consumed by the light source is converted into light. The higher the value, the better.

Old incandescent bulbs had a very low efficiency rating of between 5 and 12 lm/W. Halogen bulbs have a higher efficiency rating of between 17 and 25 lm/W. LEDs have an even higher efficiency rating of between 50 and over 100 lm/W. The theoretical limit for LEDs is around 300 lm/W. This means that once this limit is reached, a 1.5W LED can achieve the same brightness as an old 40W incandescent bulb. A good rule of thumb is that a light output of approx. 450 lm replaces a 40W bulb, and a light output of approx. 670 lumens replaces a 60W bulb.

ODSIF's way of making good and comfortable colors

To create white light, we use a white diode as the main light source. Our white diodes are high-quality diodes with a CRI value of 80 or more and a color temperature of less than 3000K.

This gives our light a soft and pleasant glow with all the necessary color components to reproduce the colors of the material or objects that the light falls on. To tone this light, we use RGB quality diodes from OSRAM, among others. We tone the light by mixing the colors from the RGB diodes with the white light. This allows us to maintain the high CRI value and create light with different color nuances. For example, when we create a golden light, we mix the white light with a strong red color, a little green color, and a small amount of blue color.