I’d like to buy a Mudita Harmony, and the next gen of Mudita Phone. I’m concerned about the amount of artificial blue light in their front lights, as I am extremely sensitive to short wavelength blue light, and overexposure causes further vision loss for me.
I understand both the Pure and Harmony have 2700k front lights. Is that made with a blue or UV diode coated in phosphor? Is it made from a narrow-band diode? Do you have a graph of the emission spectrum available? Any chance you could use a narrow-band diode in about 690 nm for the new phone?
8 Likes
Thank you for taking the time to write to us.
The concept of “color temperature” and “narrow-band emission” describe two different characteristics of light sources and are often used in different contexts.
We’ve passed on your concerns to our team and are waiting for them to respond.
However, it’s important to know that while a narrow-band diode emitting at about 690 nm could be used in an alarm clock, it might not be the most versatile or cost-effective option for general use.
A narrow-band diode at 690 nm would be particularly useful in applications where you want a very specific red light, such as in medical equipment, spectroscopy, or optical communications.
Let’s wait for our team to respond with a concrete answer if this is something we can consider.
7 Likes
Thanks so much for checking on that.
I realized I made a typo in my original post. I believe I meant to say 588-590ish nm. That would emulate the emission spectrum of the low pressure sodium lamps that used to be on our streets. It’s a spectrum that’s very gentle on the night vision. Bonus, mosquitoes tend to fly away from 530-590 nm light, according to some marketing material for yellow LED lights and some studies I found while trying to understand my light sensitivity. I tried to include a link for a low pressure sodium lamp in my post, but I guess the forum robot won’t let me. If you do an image search for “low pressure sodium lamp spectrum”, you’ll see what I’m writing about.
7 Likes
Thank you for the clarification. I did some research on low-pressure sodium lamps and it looks like they are used in some astronomical observatories because their narrow spectrum allows astronomers to easily filter out the “light pollution” from these lamps, making it easier to observe celestial objects. Like you said, they are also used in some street lighting applications where color rendering is not a primary concern, as they are quite efficient in terms of the amount of visible light produced per watt of electrical power consumed. However, their poor color rendering makes them less suitable for general-purpose lighting.
After talking to our team about your previous questions & they told me that this is not an option for future phones. However, they’re taking this under consideration for other devices.
Additionally, in response to your question about a graph of the emission spectrum available, our team has informed me that we actually ordered equipment to measure the light spectrum, so in the near future we will be able to make such measurements.
Hopefully this clears things up for you. Let us know if you have any other questions.
7 Likes
@urszula, thanks for looking into it. Can the light on the phone be just completely turned off?
What products is the team considering using 590-ish nm lighting in?
I’m looking forward to the graphs of light emissions. I find that information very itneresting and helpful.
5 Likes
Any word on that graph of light spectrum emissions?
2 Likes
@dandelionc I’ve reached out to our team & waiting for a reply.
1 Like
Thanks, I’m looking forward to the reply.
2 Likes
Hey @urszula, in addition to a light spectrum graph for the next phone, what devices are the developers considering a spectrum the emulates low pressure sodium?
I’d like to see that so much that I’d consider buying almost anything that incorporated the low sodium spectrum.
2 Likes
This is the Mudita Harmony measurement. We use warm white light rather than 690nm orange light because it is more natural and friendly to the eye.
1 Like
Thank you very much, @urszula, for giving me this information.
Is it the same spectrum as the Mudita Pure phone?
The light on the phone hurts my eyes. I’m grateful it can be turned off.
Something that may interest your team:
There’s a dopamine center in the brain that is only activated by 480 nm.
Notice the absence of that in the spectrum?
Another thing that may interest you/team, blue light stimulates wakefulness, and there’s some evidence that occurs down to the green part of the spectrum.
A company named Hooga sells reading lights in the red spectrum that are meant to not wake up other people in the room.
A person who wakes up in the middle of the night and checks their Harmony may accidentally stimulate wakefulness in themselves, and make it more difficult to fall back asleep if they are prone to insomnia.
The easiest to digest explanation of all of this that I’ve found can be listend to here: https://open.spotify.com/episode/1Car0yZ7lpslqnbcX4oSNs
To produce dopamine, an electroluminescent light would be desirable, since the peak emission of electroluminecence is about 480 nm.
To avoid unwanted wakefulness and sleep disturbances, any nm amber or red LED will outperform.
Thank you again for getting me that graph.
1 Like
… and Kompakt! It would be great if quality was preserved over all e-ink products. And should be advertised for all people that do need it.
I myself have serious eye condition (operated ablatio retinae) and larger fonts, stronger contrasts and more background light do help greatly.
Such “accessibility features” can also be advertised and create niche and small, but devoted user base too.