Infrared touch screen

[Ken Maltby]

Perhaps an experiment: Go outside in the sunlight and hold your hand out and see how much IR heating you can feel. Then come back inside and hold your hand over your IR Touchscreen and see how it compares to what you felt outside, and experience every sunny day.

(Note: Experiment may not be possible in Vancouver.)

Luck;
Ken

[newday07]

Originally Posted by Ken Maltby

Perhaps an experiment: Go outside in the sunlight and hold your hand out and see how much IR heating you can feel. Then come back inside and hold your hand over your IR Touchscreen and see how it compares to what you felt outside, and experience every sunny day.

(Note: Experiment may not be possible in Vancouver.)

Luck;
Ken

yes, but in a way our eyes are protected because anatomically in the shade. You don't look directly at the sun and for more than a second.

[Quoth]

Originally Posted by newday07

Certainly, but having skin and eyes problens and suffering from headaches for the lights and climate reasons, when I read "infrared" in the ereader description I wanted to ask, since Infrared could be very harmful as far as I know.

Certainly staring into the toaster is harmful. The IR is lower power and thus less harmful than any visible LED.

It's absolutely safe and has no biological effect at all. It's almost red LED and less power than an LED backlight.

The reason for it is because capacitive and resistive touch screens make the "white" of eInk display more grey.

The "front" light (White LEDs don't exist, they are either blue / violet with yellow phosphor or R, G and B LEDs) uses FAR more power and is safe, though if there is too much blue, it can reduce the ability to sleep easily at night, otherwise harmless.

There is more IR from a filament lamp and MUCH more from a security camera. A grill, electric fire bar, halogen security light, toaster etc has many thousands of times more IR.
Clue: You can't feel it!

[Quoth]

Originally Posted by newday07

How many LEDs are there in an ereader? Did you consider the exposure time?

Irrelevant. It's low resolution, I think on the 6.8" Kobo H2O HD Aura, 15 on ONE long edge and 11 on one short edge. Almost certainly scanned and then interpolated to work out finger position (proportion of two adjacent vertical and horizontal beams).

The risk simply doesn't exist.
Nothing visible AT ALL in a dark room and camera on nightshot. The SINGLE IR LED on the satellite remote at 1m almost blinds the camera. The remote about 1000 times less than IR from a halogen lamp.

The dusk illumination LEDs are much more power, maybe 50x at lowest setting. A LED backlight for LCD (phone, tablet, TV - Domestic "LED" TVs are LCD) is 100s of times more power, admittedly not IR, but the IR LEDs are "almost" red, that's why phone cameras, video cameras, SLR cameras etc can't filter them out.

[DNSB]

Originally Posted by newday07

How many LEDs are there in an ereader? Did you consider the exposure time?

For the only IR touch screen I dismantled, the number of LEDs did not matter since only two were on at any one time. It used a matrix array in which the LEDs were not on continuously which increases the LED lifespan while reducing the power consumption (the latter being very important to an ereader). The pattern seemed to be turning on a vertical LED and then scanning by sequentially pulsing the horizontal LEDs. Move to the next vertical LED and loop until an event is seen.

The other issue you seem to be disregarding is that the IR LEDs in a touch screen are rated in milliWatts (the one I dismantled used Osram 940nm 50mW LEDs as the senders), the incandescent lamp is rated in Watts while Ghod alone knows what the wattage equivalent for the sun at ground level would be -- NASA uses 1360 Watts per square meter for the top of atmosphere but atmosphere and sun height in the sky make a ground level number hard to determine.

To quote from one study, "The threshold i.r. irradiances for cataract formation were determined from the relationship between the incident irradiance and the lens temperature, and were in the range 163-178 mW cm-2 for long-term exposures (greater than about 5 min) under normal conditions." This was for workers in industries such as steel making.

One other study using rabbits used a 250W infrared reflector lamp (what most people call a heat lamp) placed 20cm from the rabbit's eyes. Hmmm.... 60mW not aimed at the eyes, 250W aimed directly at the eye. Hold your hand in front of your ereader and feel the heat -- not!

For the exposure time, if the level of IR is too low to significantly heat your eyes, it's too low to do any damage regardless of length of exposure. IR is just not as energetic as UV.

So basically, if you can't feel the heat, it's not going to hurt your eyes.

Please note that this is not suggesting using your remaining eye to look at an IR laser diode.

[DNSB]

Originally Posted by newday07

yes, but in a way our eyes are protected because anatomically in the shade. You don't look directly at the sun and for more than a second.

But you are looking at objects illuminated by the sun and those objects are reflecting IR. My camera with IR filter takes pictures in the sun with no problems at shutter speeds in the 1/250 of a second range while taking a picture of my Kobo H20 in a dark room with a finger on the screen shows no image after a 20 second exposure.

I do remember playing with Kodak's HSI infra-red film decades back. The black sky, the white foliage. One of my favourite B&W films which is sadly no longer available. On the other hand, I don't miss the sheer waste when bracketing each exposure since no light meters (that I was aware of) were calibrated for IR photography.

[Ken Maltby]

Sunlight, at an effective temperature of 5,780 kelvins, is composed of near thermal-spectrum radiation that is slightly more than half infrared. At zenith, sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, and 32 watts is ultraviolet radiation. Nearly all the infrared radiation in sunlight is near infrared, shorter than 4 micrometers.

Luck;
Ken

[filmo]

Advanced IR Zerotouch Touch can do much more than what simple capacitance touch, resistance touch or IR touch currently does.

http://ecologylab.net/research/publi...-zerotouch.pdf

https://phys.org/news/2011-05-zeroto...ace-video.html

[Insomniac55]

Originally Posted by newday07

How many LEDs are there in an ereader? Did you consider the exposure time?

I can guarantee you, beyond the shadow of all doubt, that there is absolutely zero danger from the IR touchscreen. The energy levels are miniscule, and IR is far from the most hazardous type of light out there - deep blue and UV is far more likely to cause damage.

The sun puts out IR light which is thousands of times brighter than the piddly little LEDs in your e-reader. Every time you go outside, your eyes are exposed to more IR light than they will be exposed to over the entire life of your e-reader.

If you have an electric stove, turn it on and look at it with your cellphone camera. It will glow purple due to the infrared light given off. The same thing happens if you take a photo of a campfire. Do you worry about looking at your stove, or at a candle? IR light is everywhere and your e-reader puts out almost none.

[newday07]

Originally Posted by mathil

It means that the beam runs parallel, and not perpendicular, to the screen. The input to the screen is given when something physical interrupts the beam.
The front light works in the same way, across the screen, and that's why your eyes won't get as tired as with a LCD screen.

If the front light is across the screen, why did they add the blue light filter?
This means that light comes the same in your eyes, isn't it?

And, I repeat, one thing is the ambient light, another thing is reading books with the rays pointed in the direction of the pupil...and for several hours a day

[meeera]

Originally Posted by newday07

If the front light is across the screen, why did they add the blue light filter?
This means that light comes the same in your eyes, isn't it?

And, I repeat, one thing is the ambient light, another thing is reading books with the rays pointed in the direction of the pupil...and for several hours a day

The visible light travels through a special light guide so that it will illuminate the screen, which involves some light scattering into the eye. The IR beams are not aimed through the light guide, they are just above it, parallel to the screen surface. The IR beams are NOT directed at your pupil. Check for palpable heat. You can't feel any, because the dose is so incredibly tiny.

I repeat, the amount you've spent worrying over this far eclipses any risk. Go relax and read. You're welcome.

Why you've posted this in the Kobo forum, when you have a Kindle and a Tolino, is quite beyond me.

[newday07]

Originally Posted by meeera

Why you've posted this in the Kobo forum, when you have a Kindle and a Tolino, is quite beyond me.

Because the most widespread ereader with infrared screen are the kobo. And tolino and kobo are now the same thing because tolino is part of kobo.

[davidfor]

Originally Posted by newday07

And tolino and kobo are now the same thing because tolino is part of kobo.

Sorry, I didn't see a release of a Tolino labelled Kobo device. Can you point it out?

And didn't Rakuten buy the back-end systems? I don't remember seeing anything suggesting they were taking over the ereader side of things.

[frostschutz]

Originally Posted by davidfor

And didn't Rakuten buy the back-end systems? I don't remember seeing anything suggesting they were taking over the ereader side of things.

The way it was reported on German sites, they took over the whole thing, and Kobo won't be selling their new Kobo devices in Germany anymore because they want to concentrate on the Tolino brand.

No one knows what it will really be like, neither Kobo nor Tolino have announced any new devices for Germany since the tolino takeover. The new h2o edition 2 is not available here in any case.

It's all speculation ( http://allesebook.de/e-book-reader/k...-tolino-70925/ )

[JSWolf]

newday07, you can go blind with your Kobo. The rest of us will enjoy reading books.