Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

LED lighting badly suppresses human melatonin production at night

sevarg.net

Post reply on HN
Print view View original

221–230 of 316 posts

Re: LED lighting badly suppresses human melatonin production at night

#221

Post by edeion »

nikvdp wrote: post #203
londons_explore wrote: post #185

Earlier quoted context omitted.

I am disappointed that many phones/tablets don't go very dim. From flagship to cheap, it seems that if you're in a pitch black room and check the time on your phone, the light will illuminate the whole room, even on the dimmest setting. I actually modded my phone by putting a resistor in the LED backlight circuit, which divided the brightness by 1000 - and it was still plenty bright at night (human eyes are logarithm…

iOS actually has a hard to find setting that lets you make the screen super dim. It's been a lifesaver when using my phone in the evening. To enable it go to Settings -> Accessibility -> Zoom and then tap the Zoom toggle switch. Once that's enabled iOS will now bring up a super secret popup menu whenever you double tap the screen with three fingers. From the little popup menu go to Choose Filter -> Low Light and your…

For what it's worth, as far as I understand, you actually need to activate the Zoom Controller to get the menu mentioned above.

Re: LED lighting badly suppresses human melatonin production at night

#222

Post by void-pointer »

nikvdp wrote: post #203
londons_explore wrote: post #185

Earlier quoted context omitted.

I am disappointed that many phones/tablets don't go very dim. From flagship to cheap, it seems that if you're in a pitch black room and check the time on your phone, the light will illuminate the whole room, even on the dimmest setting. I actually modded my phone by putting a resistor in the LED backlight circuit, which divided the brightness by 1000 - and it was still plenty bright at night (human eyes are logarithm…

iOS actually has a hard to find setting that lets you make the screen super dim. It's been a lifesaver when using my phone in the evening. To enable it go to Settings -> Accessibility -> Zoom and then tap the Zoom toggle switch. Once that's enabled iOS will now bring up a super secret popup menu whenever you double tap the screen with three fingers. From the little popup menu go to Choose Filter -> Low Light and your…

There’s two settings you can use in tandem to get an OLED iPhone brightness even lower than that.

First is the zoom trick you’ve already described, then you can use the “reduce white point” display accessibility setting to apply even more darkening.

With minimum display brightness, low-light zoom mode and white point reduction set to 100%, the display gets very very dim. If you do this in normal lighting conditions, the display is basically impossible to see.

Re: LED lighting badly suppresses human melatonin production at night

#223

Post by _dan »

londons_explore wrote: post #185
koverda wrote: post #107

Regarding the quoted e-book study: > Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session, whereas, by comparison, the print-book condition consisted of reflected exposure to very dim light. Yeah, max brightness is probably going to make an impact. I bet if you were in a room with a bright light reading a book, with an equivalent amount of lumens going into your e…

I am disappointed that many phones/tablets don't go very dim. From flagship to cheap, it seems that if you're in a pitch black room and check the time on your phone, the light will illuminate the whole room, even on the dimmest setting. I actually modded my phone by putting a resistor in the LED backlight circuit, which divided the brightness by 1000 - and it was still plenty bright at night (human eyes are logarithm…

A Macbook's minimum brightness is quite bright. The thing that annoys me no end is that if you hit the "dim" button when it's at minimum brightness, it goes black - but fades out slowly and smoothly. So they're clearly capable of being dimmer, but Apple decided we're not allowed that.

Re: LED lighting badly suppresses human melatonin production at night

#224

Post by mft_ »

pier25 wrote: post #82

The ebook reader part is a bit weird since the paper doesn't state which model they used. Many readers these days have warm LED lights. IIRC the Kindle Oasis can even adapt the temperature of the light.

It does state that it's an iPad (!) - see the Materials and Methods section, specifically page 1235.

Re: LED lighting badly suppresses human melatonin production at night

#225

Post by mft_ »

Psychlist wrote: post #52

The ebook reader part is kind of disturbing, I have a warm mode on mine that I always use, and the brightness set as low as it'll go (I find it too bright, but they seem to use a linear scale so there's not much range of adjustment). I have a red LED striplight above my bed for reading paper books so I will try using that for the ebook reader and see if I notice a difference. My main issue is that interesting ebooks…

The "eBook" study should be treated with caution, since it was conducted using an iPad, not a typical eBook reader like a Kobo or a Kindle.

Re: LED lighting badly suppresses human melatonin production at night

#226

Post by autoexec »

textbookrental wrote: post #86
jahsome wrote: post #21

Earlier quoted context omitted.

I've battled the opposite in the form of clinical, anxiety-driven insomnia my whole life. I've found it utterly debilitating at times and have quite literally struggled since birth, long before electronics and LEDs were common. I can confidently say you're so right about the number (and type) of variables. Sleep hygiene as we say in the biz is a very complex and personal issue. I've tried everything under the sun fro…

I've been a terrible sleeper for about a decade. Weeks on end where I am only sleeping a few hours a night. Can't fall asleep, can't stay asleep, just tired all the time. Tried all the sleep hygiene recommendations but made no difference. Started supplementing with creatine and about a month later had the best sleep of my adult life. Shortly after switching creatine brands, I noticed my restless legs were back and I…

> A major negative is that marijuana is usually grown with heavy pesticide use (even the certified organic stuff) so unless you grow it yourself it isn't really healthy.

Is there a source for this?

Re: LED lighting badly suppresses human melatonin production at night

#227

Post by maxerickson »

londons_explore wrote: post #185
koverda wrote: post #107

Regarding the quoted e-book study: > Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session, whereas, by comparison, the print-book condition consisted of reflected exposure to very dim light. Yeah, max brightness is probably going to make an impact. I bet if you were in a room with a bright light reading a book, with an equivalent amount of lumens going into your e…

I am disappointed that many phones/tablets don't go very dim. From flagship to cheap, it seems that if you're in a pitch black room and check the time on your phone, the light will illuminate the whole room, even on the dimmest setting. I actually modded my phone by putting a resistor in the LED backlight circuit, which divided the brightness by 1000 - and it was still plenty bright at night (human eyes are logarithm…

Some of it is probably adaptive vision.

My Pixel 6 with an OLED screen doesn't work very good as a walking light in a dark room.

Re: LED lighting badly suppresses human melatonin production at night

#228

Post by formerly_proven »

londons_explore wrote: post #195
greggsy wrote: post #189

Earlier quoted context omitted.

It’s possible to set a custom filter in iOS, which reduces the brightness even further, but only in one colour, ie red. Better than nothing. The main issue i think is that backlights tend to flicker at low brightness.

They do... But thats down to poor design decisions. Human vision extends from about 10^5 cd/m^2 to 10^-5 cd/m^2 [1]. Typical backlights use something like PWM to modulate the brightness. That means you need to be able to scale your backlight by a factor of 10^10 to cover the whole human vision range. And if your CPU runs at 1 Ghz (10^9), then at the dimmest setting then even being on for a single clock cycle would be…

Compare your hypothetical 10^10 range to the range offered by typical LCD monitors, where maximum is in the 300...400 cd/m² range and a minimum brightness less than 30 cd/m² is "outstanding". I.e. a 1:10 range.

Re: LED lighting badly suppresses human melatonin production at night

#229

Post by ilyt »

londons_explore wrote: post #195
greggsy wrote: post #189

Earlier quoted context omitted.

It’s possible to set a custom filter in iOS, which reduces the brightness even further, but only in one colour, ie red. Better than nothing. The main issue i think is that backlights tend to flicker at low brightness.

They do... But thats down to poor design decisions. Human vision extends from about 10^5 cd/m^2 to 10^-5 cd/m^2 [1]. Typical backlights use something like PWM to modulate the brightness. That means you need to be able to scale your backlight by a factor of 10^10 to cover the whole human vision range. And if your CPU runs at 1 Ghz (10^9), then at the dimmest setting then even being on for a single clock cycle would be…

> That means you need to be able to scale your backlight by a factor of 10^10 to cover the whole human vision range.

Uh, phones don't produce brightness that high. And the low range is "too low" for usefulness anyway. Your math is off by few factors

> And if your CPU runs at 1 Ghz (10^9), then at the dimmest setting then even being on for a single clock cycle would be a flash every 10 seconds - clearly unacceptable, and even then, few backlight controllers could handle a 1 nanosecond pulse!

CPU is not doing PWM, it's separate chip

And you can't realistically have more than few kHz of PWM frequency anyway coz of losses.

It's not really a technical problem in the first place, it's easy technically, just have 2 current sources, when you need low light you just PWM the low current one. And not "just putting resistor in series", that's extremely wasteful, or "single led" that would just not illuminate evenly.

Re: LED lighting badly suppresses human melatonin production at night

#230

Post by ilyt »

mft_ wrote: post #215
koverda wrote: post #107

Regarding the quoted e-book study: > Third, in the present study, the LE-eBook was set to maximum brightness throughout the 4-h reading session, whereas, by comparison, the print-book condition consisted of reflected exposure to very dim light. Yeah, max brightness is probably going to make an impact. I bet if you were in a room with a bright light reading a book, with an equivalent amount of lumens going into your e…

The study also didn't use a typical eBook reader - it used an iPad - set (as you say) to a high brightness level.

Yeah my kindle have perfectly fine backlight range for night reading.
Post reply on HN