There is some common misunderstanding on how the high output CCT (Colour Change Temperature) LEDs board technology works, mainly because of the confusion coming from the previous technology like the RGB LED’s stripline.
These RGB Stripline used a mix of 3 LED (Red, Green and Blue) to create the full colour spectrum, however they usually scored very poorly in specific colour test like CRI and Ra test. These RGB LEDs can be classified with a CRI in excess of 80, yet render important colors like the whites or reds extremely poorly. The reason for these scores is that the spectral power distribution of RGB LEDs exhibits good quality colour spikes that correspond to the output of the three LEDs (Red, Green and Blue) but creating imprecise colour renderings on other wavelengths that are the ones we are most interested for high quality light.
The new CCT LED technology is based on the same principle of mixing LED colours but in this case we take white light LEDs to achieve from the beginning a high quality light. In this situation we will have exactly the same final result of the CRI and Ra test than the ones of the SMD selected. This means we could perfectly achieve a CRI 95 if these LED are selected and still have CCT Technology.
In our case, the CCT LED Boards are created by selecting the LED SMD’s with the two colour temperature that will represent the range of colour (K) in which the board will be able to operate. In below example you can see the range taken is from 2700K to 6500K. This is simply done by creating a board with LED’s SMD of 2700K and 6500K by same amount of chips. Thanks to a controller we can achieve this CCT LED board is creating all of the colour temperature range from 2700K to 6500K by mixing these two LEDs powers in the exact proportion needed.
For example, in order to display 2700K only these LEDs will be operating while the ones of 6500K will remain off. Same idea but on the contrary for the 6500K. When selecting middle range colours, like for example 4600K, it is done by using exactly 50% of each of the LED. Same principle for other colours temperatures (K), controller will adjust powers of both LED to create exact temperature desired.
It is also important to point out, that this same controller also acts as a dimmer, from what each position of the colour temperature range also can be dimmed from 0 to 100%, from what the options of colour range and dimmer are fully customizable to achieve any position desired in the white spectrum and power.
Another point that also create confusion with the CCT LED boards is how to measure the power used and lumens output of these boards. The reason is that these LED boards have a particularity that to create them you need to have the double number of the LED from what the final result of light will be. This is due to the colour combination needed to create all of the range of color temperature and explained above. Therefore the double number of LED SMD will be needed to create the desired output, however, consumption and lumens will remain same.
Below a more visual example of a LED SMD Board of 5.6W which consist 28pcs of SMD 2835 2700K and 28pcs of 6500K. Total power will be 5.6W and lumen output around 560lm (100lm/W), however, the total number of LED investment is 10.2W, 56 pcs of SMD. So basically, the real wattage and lumens of the CCT LED PCB boards is half of the ones used in the board.
In future posts we will explain about the controllers and dimmers for the CCT LED boards. Thanks to the new technologies there is a wide range of dimmer and ways to control these boards depending on the system and switches used.