Do some LED displays emit polarized light?

[ruffrecords]

It was sunny in the UK today so I wore my polarised sun glasses outside. Later I went inside to check if the washing machine had finished its cycle and discovered I could not see the red LED? display at all. The red LED? on light I could see and also the one on the program selector switch but the main diplay of the washing cycle, time and so on I could not see at all. At first I thought the display had broken. I took my glasses off to get a closer look and suddenly it was visible. I soon worked out it was the polarised glasses that were doing it and discovered that by rotating them by 90 degrees the display again became visible.

The clear conclusion is that this display must be emitting polarised light. I am not sure exactly what type of display it is but it is red and has 7 segment parts as well as some areas with dot matrix text. By the way, the machine is made by AEG.

Is the OLED or something else or do you think AEG has added a polarizing film in front of the display??

Cheers

Ian

 

[mjrippe]

LCD are polarized.  It could be an LCD with red filter.  [edit: the "D" in LCD is Display, so LCD display was redundant again.  ;D]

 

[kambo]

the "D" in LCD is Display, so LCD display was redundant again.  ;D

nice catch  ;D

 

[AusTex64]

LED’s “generally” have a narrow angle of emission. This comment is based on my experience in the entertainment lighting business. The narrow angle thing makes it difficult to integrate a plurality of multiple color emitters without significant losses. So in your case Ian, your glasses may be polarized, and the LED source you’re viewing is quite narrow, but not necessarily polarized itself.

 

[mjrippe]

I just read this thread again and saw that you mentioned 7-segment digits but also dot matrix text.  The dot matrix definitely points to LCD, not LED.

 

[ruffrecords]

Thanks for all the comments but so far nobody seems to have explained why I can see the display if a rotate the polarised glasses through 90 degrees.

Cheers

Ian

 

[kambo]

https://www.microscopyu.com/techniques/polarized-light/introduction-to-polarized-light

The lenses of the sunglasses have polarizing filters that are oriented vertically with respect to the frames. In the figure, the blue light waves have their electric field vectors oriented in the same direction as the polarizing lenses and, thus, are passed through. In contrast, the red light wave vibration orientation is perpendicular to the filter orientation and is blocked by the lenses.

edit : u obviously can c red led light on tail/stop lights of a car in front, as they have reflektors

edit2 : there are plenty dot matrix led displays in the market...

 

[abbey road d enfer]

Obviously, according to the effect, the light emitted by the LCD is polarized. Now the question is why?
The answer is there
https://www.physlink.com/education/askexperts/ae532.cfm
LCD's actually are polarized filters. their relative orientation, controlled by voltage, allows opening or shutting light.

 

[ruffrecords]

Obviously, according to the effect, the light emitted by the LCD is polarized. Now the question is why?
The answer is there
https://www.physlink.com/education/askexperts/ae532.cfm
LCD's actually are polarized filters. their relative orientation, controlled by voltage, allows opening or shutting light.

So you are saying my washing machine has an LCD with a red back light.

Cheers

Ian

 

[abbey road d enfer]

So you are saying my washing machine has an LCD with a red back light.

Cheers

Ian

That's my deduction. As far as I can guess, the only other possibility would be that the display was an LED display with a polarizing filter in front. I can't imagine why, unless the material in front of the LED display was naturally polarized. That is not likely IMO. There are naturally polarized materials, but the effect is not as pronounced as materials specifically polarized.

 

[zamproject]

Hello

Light polarization have noting to do with wavelength...
Polarized sunglasses, don't filter the UNpolarized multispectral light of our sun BUT reflection of light that became polarized perpendicular to the surface.
Obviously sunglasses manufacturer set the polarization vertically, as most heavy reflections surface for situation when you need sunglasses are...horizontal... the road, the sea, the snow...

As already stated by Abbey, LCD are by definition polarized !
you have a non polarized backlight, then liquid crystal polarity-controled, and then a polarized foil
by polarizing the same way crystal to the foil light pass, if 90° light stop
In short you control the transparency, liquid crystal don't emit light.

Now if you look at LCD with polarized sunglasses you may have obvious issue 

Best
Zam

 

[kambo]

way dont u take a pic of this famous display and post it here!

 

[ruffrecords]

way dont u take a pic of this famous display and post it here!

I will try to make a short video of it.

Cheers

Ian

 

[kambo]

video is a hassle... this is red LCD dot

 

[ruffrecords]

video is a hassle... this is red LCD dot

OK, got it. I will post a simple pic.

Cheers

Ian

 

[PRR]

Is this washer a secret model? Frustrated, I found "a" picture in a minute.

 

[kambo]

Is this washer a secret model? Frustrated, I found "a" picture in a minute.

lol

i was just uploading one  ;D ;D ;D

 

[ruffrecords]

That is similar to mine:

Cheers

Ian