E Ink Waveforms are a closely guarded secret • Hacker News Board

Re: E Ink Waveforms are a closely guarded secret

#101

Post by userbinator » Sat, Sep 15, 2018, 5:21 PM UTC

chaoxu wrote: post #17

Recently, I brought a Dasung paperlike HD to use as a monitor. (crazy expensive, prob should've spend money elsewhere...) I thought some things were impossible with eink, but it proved me wrong. (video in a reasonable fps) It has a few different ways of display. For example: Floyd–Steinberg dithering: essentially only black and white with dithering, and the speed pretty good. A16: uses 16 shades of grey, but the spee…

Are some operations slow because the microcontroller or because it is the limit of the display module itself?

It's because the technology is a physical one --- tiny bits of reflective/absorbant particles have to physically move up and down to change the state of the pixel. It's almost like a miniaturised flip-dot display:

https://en.wikipedia.org/wiki/Flip-disc_display

The response speed increases with temperature and voltage, but temperature is not really controllable and high-voltage high-frequency drivers are not easy to make in the sizes required. Here's an article about someone making his own segmented eink display:

http://we.easyelectronics.ru/HomeTech/izgotovlenie-segmentno...

In the comments you can see a picture illustrating the difference the driving voltage makes.

(Also previously discussed at https://news.ycombinator.com/item?id=14124086 )

Related video of someone playing around with the eink material itself, showing how it responds to voltage changes and that it's possible to "draw" on one: https://www.youtube.com/watch?v=jXxSOR1PHpE

Re: E Ink Waveforms are a closely guarded secret

#102

Post by lozaning » Sat, Sep 15, 2018, 5:31 PM UTC

amelius wrote: post #54

sofon wrote: post #42

Earlier quoted context omitted.

The waveforms will all likely be disclosed in their patents too: https://patents.google.com/?assignee=E+Ink+Corp Certainly a number of drive waveforms and the basic concepts are presented. There are likely implementation subtleties or specific configurations that are not explicitly disclosed. You can probably figure out a lot about both the implementation, and motivation by digging through the patents.

Yes, it would be quite stupid to guard the secret and not patent it. So the title of the article doesn't make much sense.

There is a reason that Coke hasnt patented the Coke formula.

Re: E Ink Waveforms are a closely guarded secret

#103

Post by hestipod » Sat, Sep 15, 2018, 5:39 PM UTC

dorfsmay wrote: post #85

zamadatix wrote: post #74

Earlier quoted context omitted.

For 1,000 dollars you can get a hell of a monitor setup instead.

That wouldn't work outside in bright light, and would send bad blue light though. Been waiting for an e-ink laptop specifically for working with it outside in the sunlight, and in the evening, since blue light is supposed to be really bad for humans at night.

Me too...E-Ink/Clear Ink/Mirasol whatever I don't care...just something reflective and not an LED backlight shining in my eyes. I am angry the patent greed has stunted this for so long. There is no physical reason we cannot have laptops and desktop displays with this tech, it's all business bullshit.

Re: E Ink Waveforms are a closely guarded secret

#104

Post by hestipod » Sat, Sep 15, 2018, 5:46 PM UTC

akvadrako wrote: post #98

akvadrako wrote: post #80

Earlier quoted context omitted.

You need brightness too. I have both e-ink and MBP screens - both work in the sun.

Just to give some numbers: e-ink has a contrast ratio of about 20:1 with 40% reflectance. A sunny day is 10000 - 30000 nits, giving at least 4000 nits of brightness. The 2018 MPB screen has a 1500:1 contrast ratio and about 500 nits of brightness. So if e-ink is really easier to read in the sun (which I think) then brightness is much more important.

It's not that simple. I cannot explain the physics/physiology of it with any authority, but as someone who suffers from severe strain and headaches with LED (and some CCFL) backlighting I can you it's feeling like something to do with direct vs reflected lighting vs some brightness or contrast metric. Looking at E-Ink or print on paper in a variety if lighting is generally fine (as long as it's bright enough for a normal person to read..obv too dark and different strain occurs)...but an LED backlit LCD even on low settings (so maybe 10% of those 500 nits) results in problems. Stare at a lightbulb vs staring at a white wall that bulb is shining on for a simple illustration. I don't believe it's polarisation either since wearing polarized sunglasses doesn't result in strain and just like an LCD polarizes the light that reaches your eyes, so do the glasses.

Re: E Ink Waveforms are a closely guarded secret

#105

Post by hestipod » Sat, Sep 15, 2018, 5:53 PM UTC

enriquto wrote: post #78

bonzini wrote: post #68

Earlier quoted context omitted.

A reflection of the sun on a mirror is a reflection of a very strong light source through a perfectly reflective medium.. A book or an e-ink screen is still ultimately sunlight, but it has scattered (which is reflection too) while passing through the atmosphere many times before reaching what you are looking at.

So it's a question of total light intensity, not of being reflected or "direct" (whatever that means).

I don't think so myself because I don't have pain in full sunlight reading print or E-Ink which is much brighter "nits" than an LED backlight produces ....but even low settings on an LED backlit computer hurt. There is in my opinion a difference between looking into a light source and looking at things that are visible due to reflected light like E-Ink, paper, the objects around us even if I cannot quantify it with scientific explanation.

Re: E Ink Waveforms are a closely guarded secret

#106

Post by hestipod » Sat, Sep 15, 2018, 5:55 PM UTC

Tharkun wrote: post #43

chaoxu wrote: post #25

Earlier quoted context omitted.

1. Currently, I use it for writing code and reading papers. However, I still want the monitor to be a good enough drop-in monitor for things I need to occasionally do. For example, I need to switch to a browser window to check what was that error I'm getting. 2. Visual snow syndrome: Many had their first experience of visual snow after staring into the screen for too long. People who believe in that is the cause of v…

I was under the impression that Visual Snow was a symptop of anxiety?

Visual snow could also be to to flickering from PWM, or more likely temporal/spatial dithering (a leading theory in LED LCD based eyestrain but as yet unproven as the cause). Even a white background on a monitor, even a static image, isn't just static white...it's constant flickering of pixels to make a certain "white" and to smooth moving images as well. Whatever the ultimate cause it's not normal or healthy to stare at emitted light most of the day and most of us do...add flickering and other visual tricks displays use and it's no wonder eyestrain exists. Nobody would stare at a 300 nit lightbulb for hours and call that reasonable, but that's what backlit LCD displays are. I didn't have a problem for most of my life, and still don't with books under proper lighting, but now I have a severe one with LCDs that and cannot find a definitive answer or fix and frankly it's crushing a last chance I have to be somewhat independent and survive.

Re: E Ink Waveforms are a closely guarded secret

#107

Post by avhon1 » Sat, Sep 15, 2018, 5:57 PM UTC

akvadrako wrote: post #61

mikekchar wrote: post #51

Earlier quoted context omitted.

Not the OP, but the main reason I want an e-ink display (for programming, which may include animations) is so that I can do it in full sunlight. I work remotely and often work in public places. Working on a park bench, for example, is normally impossible, unless it happens to be cloudy and I'm in a shady place. I'm just hoping e-ink becomes a mainstream thing before I retire.

The new MacBook Pro screen work in full sunlight - it's just about being bright enough. Another option is to place the back of a plastic screen towards the sun, using it as a backlight.

That's a very power-intensive way of doing it. Sunlight is about 120 watts per square meter[0]. My 14-inch laptop (a Thinkpad T430) display has an area of 0.0543 square meters, so in full sunlight it is illuminated by 6.5 watts of light.

White LEDs are currently approximately 25% efficient (and have a limit of 44%)[1], so my LCD display needs to use 26 watts of electricity to be as bright as direct sunlight landing on it.

My laptop's backlight can't actually do that, but if it could, it would exhaust 70 watt-hour battery in less than 3 hours, without accounting for any power used by the CPU, network card, RAM, or hard drive.

[0] https://en.wikipedia.org/wiki/Sunlight

[1] https://en.wikipedia.org/wiki/Luminous_efficacy#Examples_2

Re: E Ink Waveforms are a closely guarded secret

#108

Post by dfox » Sat, Sep 15, 2018, 6:00 PM UTC

cptskippy wrote: post #87

ben_w wrote: post #46

Earlier quoted context omitted.

People keep saying eInk is better than reflective black and white LCD, such as that found on calculators. I’m unconvinced, but (obviously) to test this I would have to actually get a monitor sized black and white reflective display, and I can’t find any of those — largest I have found so far is 320x240 for about £200

I haven't seen a reflective black and white LCD matrix that didn't suck. Think TI-82 calculators. That being said the segmented LCDs like those found in 4 function calculators and wrist watches usually look fantastic.

IMO you do not have to go that far for graphical reflective LCD that didn't suck: TI-89 has one. Also LCDs in Psion handhelds were quite reasonable.

Re: E Ink Waveforms are a closely guarded secret

#109

Post by diffeomorphism » Sat, Sep 15, 2018, 6:17 PM UTC

Avamander wrote: post #72

ben_w wrote: post #49

Earlier quoted context omitted.

Emissive displays don’t generally match the brightness of their surroundings; even with automatic adjustment, most are physically incapable of being as bright as a newspaper in daylight, and many cannot be as dim as a newspaper lit only by one of those small book-reading lights without being switched off entirely. There’s also the spikey spectrum, which looks the same consciously but I’ve seen claims [1] that is mess…

I think most people are forgetting that LED backlights are controlled usually using PWM which flickers, fast, but still flickers. I haven't found any research about how it might affect humans. I suspect it would be better if no-flicker current-controlled LED backlight was used instead of PWM.

According to notebookcheck only about half the devices they tested use PWM:

https://www.notebookcheck.net/Why-Pulse-Width-Modulation-PWM...

It seems to be well known that it for low frequency PWM it causes headaches for some people, so I would expect that there is at least some research in that direction. That said, it seems to only be a problem for few people and only for very low frequencies.

Re: E Ink Waveforms are a closely guarded secret

#110

Post by abdullahkhalids » Sat, Sep 15, 2018, 6:22 PM UTC

userbinator wrote: post #3

Is it really "closely guarded", or "worst guarded"? Anyone with a logic analyser and a few hours can probably figure it out easily enough... and some have even gone beyond what the official controllers can do: https://hackaday.io/project/11537-nekocal-an-e-ink-calendar/... (previously discussed at https://news.ycombinator.com/item?id=16140284 ) More research from others: http://essentialscrap.com/eink/ https://news.y…

You forgot the best resource https://github.com/joukos/PaperTTY discussed at https://news.ycombinator.com/item?id=17896825

You can buy fairly cheap displays from https://www.waveshare.com/ along with Raspberry Pi HATs and the PaperTTY project gives the power to do a partial refresh instead of full screen refresh on these screens. The waveforms are available in the Waveshare open source code and you can modify them as you will.

I am getting my screen next week and hoping to make my own little emacs only laptop using a Rpi Zero.