Reflective displays vs Emissive displays

[viceant]

Originally Posted by harriska2

Hoping it's amazon with deep pockets. Young students really need this device for reading and filling out worksheets. It would save a ton of paper. And could have huge cost saving benefits for schools that get free books or make their own textbooks (at $50-$100 per textbook). Could pay for itself quickly.

Those activities can be done with a tablet and I think there's not much people who do their homework outdoors.

And it's not proven LCD screens damage eyesight.

Enviado desde mi Redmi 3S mediante Tapatalk

[mdp]

Originally Posted by viceant

And it's not proven LCD screens damage eyesight

What are you replying to Viceant?
And, there is no need for proof, LCD "at noon" is bad for your eyes comparatively as much as E-Ink "at midnight". ( = It is a matter of environment.)

[viceant]

Originally Posted by mdp

And, there is no need for proof, LCD "at noon" is bad for your eyes comparatively as much as E-Ink "at midnight". ( = It is a matter of environment.)

I don't know whether I understand you or not. If you're saying what is important is the light level in the environment, then change it and you don't need a e-ink screen.

Light is light: what's the difference between light reflected or emitted?

[mdp]

Originally Posted by viceant

I don't know whether I understand you or not. If you're saying what is important is the light level in the environment, then change it and you don't need a e-ink screen.

What is important is, more completely, the complex lighting of your studying environment, together with and playing with the material properties of your medium (including reflective properties of the screen, type and amount of glare, mirroring properties, not to mention how "convincing" in general the effect is, and how environmental light modifies it). That determines the comfort of your eyes - and you do not need studies to tell you: you have all the feedback system already wired and working in your nervous system. Most often signals of suboptimality are triggered which the users utterly disregard, so the basic cybernetic properties of the human system are paradoxically non trivial here.

Of course if you happen to squint at your LCD you can dim the lights and get a better effect, if you happen to be indoors (which you are not to assume) - only, (1) those who are outdoors cannot easily access dimmers, and (2) nonetheless, easily the darkness in which an indoor study has to be put to bring focus on a backlit monitor to optimality can be unreasonable in daytime.

Originally Posted by viceant

Light is light: what's the difference between light reflected or emitted?

As I expressed many times, often with the formula that «it is stupid to fight light with light», light reflected uses the environmental light, while light emitted has to fight with the environmental light.

It is not simply «light reflected or emitted», as if we were talking of a torch beaming in your eyes directly or through a mirror: it is a matter of the whole system.

Also, again as per the above, ask your eyes what the difference is, they know.

[viceant]

Originally Posted by mdp

It is not simply «light reflected or emitted», as if we were talking of a torch beaming in your eyes directly or through a mirror: it is a matter of the whole system.

Also, again as per the above, ask your eyes what the difference is, they know.

Can you link experiments that prove your assertions? I don't confide in my experience or feelings.

[mdp]

Originally Posted by viceant

Can you link experiments that prove your assertions? I don't confide in my experience or feelings.

Nice one ; )

Edit: for the distracted, Viceant is asking "What if I could not trust... my sensory feedbacks". Which is also asking, a là Descartes, "What if my senses trick me".

It reminded me though possibly marginal one note from Sapolsky, "How does your limbic system know you are relaxed or tense? It checks if your muscles are".

Well, just for the intellectual tease, one answer would be: "Proceed by absurd: what if you did not trust them feedbacks". And lose all your perception of comfort etc. .... On the weak grounds of distrust. Check the consequences.

[viceant]

Originally Posted by mdp

Nice one ; )

Well, just for the intellectual tease, one answer would be: "Proceed by absurd: what if you did not trust them feedbacks". And lose all your perception of comfort etc. .... On the weak grounds of distrust. Check the consequences.

Reduction to absurd is for maths issues and this is not maths. You're, also, making a straw man. Placebo effect is real and too much people thinks homeopathy works.

I won't discuss these issues here.

Enviado desde mi Redmi 3S mediante Tapatalk

[DuckieTigger]

Originally Posted by viceant

Reduction to absurd is for maths issues and this is not maths. You're, also, making a straw man. Placebo effect is real and too much people thinks homeopathy works.

The difference of backlit LCD and frontlit eink is not a placebo effect. The quality of the light is different. I am not saying one is inherently better or worse for your eye health. I am just saying there is a measurable difference. It also makes a big difference what light source you are using and how you go about bouncing the light off. A reflection does usually mean bouncing light off of a mirror like flat surface. That is not what is happening with eink. Ignoring glare for a second (every eink I have see does have glare, even if you usually have to go out of your way to see it), what makes eink visible is diffusion. That can come either from external light sources or a front light. Polarization matters as well. It is not the direction the light travels, but what direction it "swings" while it is going wherever it is headed. Reflection changes the polarization to be "sideways" from the angle of the mirror. Reflecting polarized or diffused light off a surface will result in polarized light which direction will depend on light source, position of mirror and position of the eye. Diffusion is viewer independent and not polarized, whether you use a polarized or non-polarized (diffuse) light source.

So far, so good? Now it gets more complicated. An backlit LCD panel is neither diffuse nor reflected. But it is still polarized through a set of polarization filters. The backlight itself is diffuse, similar to how a photographic softbox looks like. That diffuse light gets filtered to be polarized, this time around not through reflection, but by eliminating the majority of the light that swings in an undesired direction. Then it hits the liquid crystal layer that will turn the light depending on how much voltage is applied. Then it hits another pol filter that will let white light through the best and black the worst, depending on how far you twist the light. Then it hits a color filter in the case of a color LCD. No matter how you eluminate eink, the resulting light is always diffuse. More natural light, just like a traditional paper book looks.

[viceant]

Originally Posted by DuckieTigger

The difference of backlit LCD and frontlit eink is not a placebo effect. The quality of the light is different. I am not saying one is inherently better or worse for your eye health. I am just saying there is a measurable difference. ....

Ok, thanks for the lesson. But, as you say, we don't know yet whether LCD light causes poor eyesight or another health issue. I do prefer e-ink, but it's only my preference.

[Quoth]

Originally Posted by viceant

Ok, thanks for the lesson. But, as you say, we don't know yet whether LCD light causes poor eyesight or another health issue. I do prefer e-ink, but it's only my preference.

The LED lighting inherently has blue which is bad for the retina and suppresses sleep. It pretty much is clear that too much tablet time, especially at night, is bad for you.

Now eink can have a frontlight. Older ones are "white LEDs" like LCD, however you can turn it off.

The "night" colour of LCDs is done by varying the LCD, not the "White LED" backlight. White LEDs are a composite device, they are really Blue/Violet/UV (depending on cost) with a yellow phosphor. With age there is less yellow. Hence cheaper LCD backlights can look a little purple and all go more violet/purple with age. Conversely my 2000 and 2002 Laptops (which I still have) use CCFL which are a kind of mercury vapour discharge tube giving off mostly UV. They use a much thicker phosphor than LEDs and also a mix of phosphors to better simulate a full spectrum. The blue phosphor (not usually present on LEDs as they are blue) wears faster as on Plasma TVs, so they develop a yellow cast. Our older HDTV is also CCFL, the newer one is LED backlit. Cheaper TVs use LEDs only at the edge.

Newer "comfort" front lights don't use the nasty "white" LEDs, or at least not solely, the colour is achieved by different colours of LED. Some might use RGB LEDs which are Red, Green and Blue chips in one package. A Spectrometer or a prism would tell as RGB LED have 3 spikes. A White LED has a diffuse band from reddish-orange to yellow-green, peaking in yellow and a blue peak. Most have no cyan.

The new filament style LED room lamps are interesting. Each stick is about 20 to 26 LEDs. The power is low per LED so more efficient and phosphor coating works better and ages slower. The entire stick is coated with the yellow phosphor to convert enough blue/violet/UV light. Also the better colour ones have some other colours of LED on the stick (red and cyan) to improve colour rendition. Reading an eink illuminated by these is much better than LCD or OLED screens because there is almost no UV and less blue than regular "White" LEDs. The spectrum is closer to a halogen than traditional LED lamp or even a Fluorescent lamp (tube or CFL or CCFL). Another benefit of the LED stick filaments is that each stick is about 55V. Thus 2 sticks about 110V and 4 sticks 220V. No SMPSU is needed, which generates heat, has lower life than LEDs and usually creates radio interference. So some stick filament LED lamps will also work on dimmers.


So if you have a suitable ambient light / bedside lamp, it's a fact that eink is better for the retina and your sleep patterns than LCD and most OLED phones/tablets.

Nothing to do with placebo.

It's also true that all LCDs have only one polarisation of light, OLED and LCD have narrower view angle and light emission than eink. The eink is a milky coloured liquid. Each cell has a number of black balls. It's got a massive viewing angle, totally diffuse like paper and no polarisation. However there is no evidence I've read that having only one polarisation of light does any harm.

[murraypaul]

Originally Posted by FrustratedReader

The LED lighting inherently has blue which is bad for the retina and suppresses sleep.

One of those is scientifically validated, the other is not.

So if you have a suitable ambient light / bedside lamp, it's a fact that eink is better for the retina and your sleep patterns than LCD and most OLED phones/tablets.

One of those is scientifically validated, the other is not.

Damage to the retina from reading on a tablet/phone has the status of FUD, not science.

[leebase]

And the sleep studies are suspect with small number of people studied.

[Quoth]

Unless you are selling LCD tablets or LEDs, I'd err on the side of caution. People that don't read much or have never used eink think it's madly expensive for a single use device. Mostly people that read lots on eink only use phones for convenience or tablets for larger than A5 PDFs. It's not placebo.

There are very rich vested interests such as Google, Samsung and Apple selling phones that cost x5 what I'd pay.

[leebase]

FUD FUD FUD --- FUD Alert.

FYI - reading is bad for your eyes.

[murraypaul]

Originally Posted by FrustratedReader

Unless you are selling LCD tablets or LEDs, I'd err on the side of caution.

You keep doing this, implying that anyone who disagrees with you must be being paid off. It isn't a helpful debating tactic.

People that don't read much or have never used eink think it's madly expensive for a single use device. Mostly people that read lots on eink only use phones for convenience or tablets for larger than A5 PDFs. It's not placebo.

I'm not sure what the first two sentences have to do with the third?
There is a difference between "I prefer reading on eInk" and "LCD displays damage your retinas". There is a difference between "I find that reading on LCD displays make me sleep worse" and "LCD display damage your retinas".

There are very rich vested interests such as Google, Samsung and Apple selling phones that cost x5 what I'd pay.

Again with this?