Why are blue LEDs brighter than others？

Using Arduino LEDs and Multiplexing
1

Hi everyone, I am a beginner.

When I was experimenting, I found that blue LEDs are always much brighter than LEDs of other colors. Even dazzling.

This question may be very simple for you, but I don’t know why.

2

Maybe the blue LEDs you have happen to be brighter than the other LEDs you have. They are always working on makng LEDs more efficient and brighter, maybe the blue LEDs you have are a more modern design than the others. Some LEDs have a wide viewing angle, some have a narrower viewing angle. They are useful for different purposes. A narrow field of view makes LEDs look brighter, if you look at them dead on, but less bright from other angles.

3

In fact, the (human) eye is most sensitive to green IIRC.


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This is why - before the recent "trendy" use of blue, car vehicle instrumentation at night is properly illuminated in green. If blue LEDs seem brighter, it is because the green ones you see are just - old!

Blue - "ice" - LEDs have been popular as "Xmas" lights but again, for their actual power consumption, they are nowhere near as visible as green or yellow.

4

I tried to put one red, one green, one blue, one yellow, one orange and one pink LED side by side. Then I tried different resistor to find the combination where LEDs had the same brightness. I ended up with

Red: 2k2
Green: 22k
Blue: 6k8
Yellow: 910R
Orange: 1k
Pink 3k9
5

That looks about right. Yes I have found blue LEDs to require much less current to stop them being painful to look at.

human vision becomes far more sensitive to blue when ambient light levels are low, a phenomenon known as the Purkinje shift.

This is from

It is worth a read.

For any photon of light the energy it contains depends on the colour or wavelength. Blue light has a much shorter wavelength than red light. So the photons carry more energy to excite your retina than any other colour.