COLOR COMBINTIONS OF LED LIGHTS
In LED lights ‘Color’ refers to the color of light that the diode emits – this can be any color. Colored LEDs are all around us, in decorative applications, also being used for communication and indication purposes.
LEDs can generate up to 16 million colors.
The material used in the semiconducting element of LED determines its
color. A color-changing
LED contains three separate diodes within the same bulb casing. Each of these
diodes emits its own, specific color – red, green, or blue. When all three
diodes are switched on at full capacity, white light is produced. Adjusting the
intensity of each diode allows a range of different colors and shades to be
created.
RGB Concept
The RBG concept is an additive model, these colors are used because our eyes see all colors as different combinations of red, green, and blue wavelengths.
Red and amber LEDs use the
aluminum indium gallium phosphide (AlInGaP) material system. Green diodes,
whereas, use gallium phosphide and blue diodes to use indium gallium nitride. So
primary colors are red, green, and blue.
Current passing through all 3
diodes at equal intensity produces white light. Since LEDs are so small and the
diodes are so close together, our eyes see the combination of colors, rather
than each individual colored diode.
By adjusting the current so that it only flows through
2 diodes, an additional 3 colors can be created. Passing a current through the
red and blue diodes creates magenta, red and green make yellow, and blue and
green produces cyan.
Someother
colors are created by adjusting the level of current running through each
diode. If, for example, the red and green diodes are switched on but the green
is running at 50%, a color between red and yellow will be created; in this
case, orange.
How
many colors can be created using RGB?
There are claims that color
mixing software can produce 16 million colors. In fact, this is based on simple
arithmetic of having 256 levels of output
The RGB model uses a color code to
quantify the intensity of each diode. When displaying a color image on a
screen, each pixel has a specific RGB value. In 24-bit color, this
value is between 0 and 255, where 0 is no color and 255 is full saturation.
So the color code for orange, to
follow on from the earlier example, would be 255, 128, 0. This can also be
presented in percentage form, 100%, 50%, 0%.
Since each of
the three colors can be set to 256 values (including zero), 256*256*256 =
16,777,216 possible colors are at your disposal with the slide of a remote.
A purple pixel will have a lot of red
and blue, but little to no green. For example, the following RGB value might be
used to create purple:
R: 132 (84 in hexadecimal)
G: 17 (11 in hexadecimal)
B: 170 (AA in hexadecimal)
Since each color has 256 possible values, it can also be
represented using two hexadecimal values (16 x 16), as shown above.
The standard way to display an RGB value is to use the hexadecimal values for
red, green, and blue, preceded by a number symbol, or hashtag.
Therefore, the purple color above is defined in RGB as #8411AA.
In color changing LEDs, a
microcontroller is used to control whether each diode is switched on or off. For
dimming a diode, LEDs uses Pulse Width Modulation (PWM).
PWM works by rapidly turning the diode on and off. This flickering is so fast that it is undetectable to the human eye. Hence, our eyes only see the net result i.e., the color. Most LEDs flicker at 1000Hz, but the human eye can only identify flickers slower than 200Hz.
RGBW LED Lights
A
standard RGB LED uses 3 colored diodes, the RGBW on the other hand uses 4
diodes, the extra one being a white diode.
This
white diode outputs pure white light, so when you need white color, only the
white diode is working. The other three LEDs will switched on when you need
colors.
RGBW LED
can produce bright pastel colors in addition to all the colors the RGB light
produces.
Additionally, and more importantly, owing
to the high CRI white LED, RGBW’s light output is suitable for
task or mood lighting, and you can see objects well.
The RGBW LED
can also change the color temperature of the light produced. If you want task
lighting, the white and blue diodes merge lighting to produce a cool
temperature. If you want to relax, the red and white diodes give you that
familiar warm white color.
If you do not require brightness
or task-based lighting, then the basic RGB LED can be enough to provide color
and aesthetics.
In the RGBW
LED, the white color produced is a purer tone of white, while in RGB, the three
colors come together and make a slightly bluish-white.
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