Sunglasses and Electronic Displays

Electrical and electronic topics for small boats
Jefecinco
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Sunglasses and Electronic Displays

Postby Jefecinco » Fri May 10, 2019 10:29 am

I have a nice pair of non-prescription sunglasses with a reader lens in the bottom half of the lenses. The reader lenses are a necessity for fishing because of dealing with fabricating and repairing terminal tackle every hour or so.

However the polarized feature of the glasses make electronic displays almost impossible to read. So far my option seems to be to carry a set of clear lens readers and use them whenever needed although I prefer not to carry another pair of glasses. Another option would be a pair of non-polarized reader sunglasses which I have so far not found. Are the latest displays readable with polarized sunglasses? I see almost all the manufacturers of marine electronics claim the displays are "sunlight readable". Is anyone using polarized sunglasses able to read the marine electronic displays?
Butch

jimh
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Re: Sunglasses and Electronic Displays

Postby jimh » Fri May 10, 2019 10:34 am

The problem with viewing electronic displays while wearing polarized lenses is common, and it occurs mostly with older technology displays. Older technology displays use polarizing filters which result in the light they emit being uniformly polarized. If the polarization of the lenses in eyeglasses being worn by a viewer of the display are designed to filter out light with the polarity being emitted by the display, the display visibility is greatly reduced. There is no remedy for this except to get a more modern display.

Newer display technology provides a wider field of view for the display and does not emit such highly polarized light as older displays. This is particularly true of modern color displays.

MattFL
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Re: Sunglasses and Electronic Displays

Postby MattFL » Fri May 10, 2019 11:05 am

Tilt your head while looking at the display, when the polarization of the glasses lines up with the polarization of the screen the image will become visible. Not a perfect solution, but inexpensive!

jimh
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Re: Sunglasses and Electronic Displays

Postby jimh » Fri May 10, 2019 12:55 pm

I just tested five displays to see if viewing them while wearing polarized sunglasses caused a problem. My results:

  1. a DELL U2312HM computer display: transmission of light from the display through the polarized lenses was completely blocked over a very narrow range of orientation of the polarized sunglasses, but other than this very narrow arc of orientation when the sunglasses were oriented at 90-degrees to horizontal, the display was easily viewed.
  2. an Apple iPhone 3, a very old model; same results as above at 1
  3. an older SONY Bravia HDTV: same results as above at 1
  4. a recent model Apple iPod with the RETINA display: there was no orientation of the polarized sunglasses that caused a complete blocking of the light from the display; there was a small arc in the orientation of the sunglasses that caused a very slight dimming of the light from the display.
  5. a Lowrance HDS-8: there was no orientation that blocked all light; holding the glasses at a 45-degree angle caused the display to appear to dim to about half-brightness

These result corroborate my earlier comments that with older technology displays the light being emitted is very highly polarized, resulting in the potential for almost complete blocking of that light when seen through polarized sunglasses if the orientation of the sunglass polarizing filter is made to be orthogonal to the polarized light from the display, and that with newer technology displays this problem does not occur.

Some marine displays seem less prone to having all light blocked than computer, smartphone, or entertainment displays which are likely not intended to be viewed while wearing polarized lenses.

MattFL
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Re: Sunglasses and Electronic Displays

Postby MattFL » Sun May 12, 2019 6:19 pm

More data points -- My wife's 2012 Prius screen is horrible. The display and backup camera are all but invisible when wearing polarized glasses. I'm surprised they even let it go to market like that. I do not recall having the same problem in her previous 2008 model year Prius, which had a much brighter and clearer screen in general.

On the flip side the screen in my 2017 Chevy Colorado is perfectly clear when wearing polarized glasses. The Garmin GPSMAP 541s in my boat, that I bought back in 2010, is clearly visible through polarized glasses if I'm standing right in front of it, but is impossible to see through polarized glasses if I'm standing to the side of it, such as when my son is driving and I'm trying to check on him.

jimh
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Re: Sunglasses and Electronic Displays

Postby jimh » Mon May 13, 2019 8:15 am

Newer color displays have wider viewing angles, which is also a benefit, even if not wearing polarized lenses.

Jefecinco
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Re: Sunglasses and Electronic Displays

Postby Jefecinco » Mon May 13, 2019 10:16 am

The responses are very helpful, thank you.
Butch

jimh
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Re: Sunglasses and Electronic Displays

Postby jimh » Mon May 13, 2019 11:04 am

MattFL wrote: My wife's 2012 Prius screen is horrible. The display and backup camera are all but invisible when wearing polarized glasses.


Let me make a guess about this situation:

Usually polarized sunglasses only admit light with vertical polarization. The block light with horizontal polarization.

An electronic display will often emit light that is highly polarized. An electronic display will often have a particular aspect ratio. Many electronic displays are made with an aspect ratio that is wider than the display height, due to anticipation of use in reproducing motion pictures, which now are always in a wide-screen format.

If a display's physical orientation is changed from a landscape format to a portrait format, the polarization of the emitted light will change along with that rotation.

In light of the above--pun intended--a display made to emit vertically polarized light in a landscape orientation would emit horizontally polarized light when rotated to a portrait orientation.

Is the PRIUS display oriented in landscape or portrait orientation?

MattFL
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Re: Sunglasses and Electronic Displays

Postby MattFL » Mon May 13, 2019 11:16 am

The Prius is more landscape, but the polarization orientation seems to be diagonal. Looking directly at it through glasses the screen is too dim to read, but you can tell it's on. Tiling your head one way makes the screen appear black, and tiling your head the other way makes the screen more visible. It is as if they could not decide if sunglasses were polarized vertically or horizontally, so they hedged and went 45-degrees, making the screen basically unusable for everyone.

jimh
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Re: Sunglasses and Electronic Displays

Postby jimh » Mon May 13, 2019 11:45 am

Try different sunglasses in your test. Maybe the orientation of the polarizing filter in the sunglasses is at 45-degrees from horizontal.