Author Topic: EEVblog #898 - LCD Contrast Experiments  (Read 12237 times)

0 Members and 1 Guest are viewing this topic.

Online EEVblog

  • Administrator
  • *****
  • Posts: 29482
  • Country: au
    • EEVblog
EEVblog #898 - LCD Contrast Experiments
« on: July 07, 2016, 11:03:16 pm »
What is the difference between LCD viewing angle and bias angle?
How does adjusting the LCD bias voltage effect the display?
What is LCD Ghosting?
Also a demonstration of Photoelastic Birefringence in polycarbonate plastic display covers.
Dave investigates the Liquid Crystal Display viewing angle problem in the EEVblog BM235 Multimeter.

« Last Edit: July 08, 2016, 12:45:42 am by EEVblog »
 
The following users thanked this post: Bobson, MK14

Offline imidis

  • Frequent Contributor
  • **
  • Posts: 427
  • Country: ca
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #1 on: July 08, 2016, 12:56:40 am »
Awesome! Thanks for trying it.   :)
Gone for good
 

Offline nidlaX

  • Frequent Contributor
  • **
  • Posts: 649
  • Country: us
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #2 on: July 08, 2016, 03:40:37 am »
Very nice Dave! For your customers, will it void their warranties if they choose to change the bias resistor?

I'm tempted to do this for my Greenlee DM-510A, but I'm almost certain the warranty will be void if I do.
 

Offline GEuser

  • Frequent Contributor
  • **
  • Posts: 501
  • Country: 00
  • Is Leaving
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #3 on: July 08, 2016, 04:18:19 am »
Good one Dave , i dunno where you find the time .

You forgot though to turn on the backlight at the end to see what happens .
Soon
 

Online EEVblog

  • Administrator
  • *****
  • Posts: 29482
  • Country: au
    • EEVblog
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #4 on: July 08, 2016, 04:52:58 am »
You forgot though to turn on the backlight at the end to see what happens .

Yep, I forget a lot of things.
 

Online EEVblog

  • Administrator
  • *****
  • Posts: 29482
  • Country: au
    • EEVblog
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #5 on: July 08, 2016, 04:53:41 am »
Very nice Dave! For your customers, will it void their warranties if they choose to change the bias resistor?

Not unless the mod demonstrably caused the fault.
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 9139
  • Country: au
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #6 on: July 08, 2016, 05:07:33 am »
Good to know.

Then again, people who purchase a product like this are more likely to have the skills to make such a mod.  I know I could - but, at the moment, I have no plans to fix the backlight buzz nor contrast.  This might change if a situation arises where there is a clear benefit - but I'm not into mods for the sake of mods.
 

Online EEVblog

  • Administrator
  • *****
  • Posts: 29482
  • Country: au
    • EEVblog
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #7 on: July 08, 2016, 05:09:47 am »
Good to know.
Then again, people who purchase a product like this are more likely to have the skills to make such a mod.  I know I could - but, at the moment, I have no plans to fix the backlight buzz nor contrast.  This might change if a situation arises where there is a clear benefit - but I'm not into mods for the sake of mods.

I won't bother modding my own lab units, doesn't cause an issue for me.
 

Offline TheDefpom

  • Frequent Contributor
  • **
  • Posts: 272
  • Country: nz
  • YouTuber Nerd
    • The Defpom's Channel
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #8 on: July 08, 2016, 05:21:48 am »
The polarizing effect is due to the crystallization of the plastic housing, polarizing filters are used to check for the internal stresses and melt flow properties of these kinds of plastics, if you look at the effect through the filter, you can actually see it shows where the injection moulded fill points where (the gates), but normally you would not see this at all unless you are looking through a polarized filter, such as sunglasses, etc.
« Last Edit: July 08, 2016, 05:34:21 am by TheDefpom »
 

Offline TheDefpom

  • Frequent Contributor
  • **
  • Posts: 272
  • Country: nz
  • YouTuber Nerd
    • The Defpom's Channel
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #9 on: July 08, 2016, 05:35:37 am »
I think I will have a look at my one and decide if I should replace that resistor or not.

Offline f4eru

  • Frequent Contributor
  • **
  • Posts: 546
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #10 on: July 08, 2016, 01:10:42 pm »
Wov !!

Dave made a demo of the Davecad V2.0 in this video, with animation features !
Innovation in the CAD field :)
I hope this V2.0 will be released soon :)
 
The following users thanked this post: Bobson

Online EEVblog

  • Administrator
  • *****
  • Posts: 29482
  • Country: au
    • EEVblog
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #11 on: July 08, 2016, 01:20:51 pm »
Dave made a demo of the Davecad V2.0 in this video, with animation features !
Innovation in the CAD field :)
I hope this V2.0 will be released soon :)

Big announcement video coming shortly, I've sold DaveCAD to a large CAD company who shall remain nameless right now. Will post it from my new private island.
 

Offline nctnico

  • Super Contributor
  • ***
  • Posts: 17463
  • Country: nl
    • NCT Developments
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #12 on: July 08, 2016, 02:23:13 pm »
Dave made a demo of the Davecad V2.0 in this video, with animation features !
Innovation in the CAD field :)
I hope this V2.0 will be released soon :)
Big announcement video coming shortly, I've sold DaveCAD to a large CAD company who shall remain nameless right now. Will post it from my new private island.
Let me guess: Staples?
There are small lies, big lies and then there is what is on the screen of your oscilloscope.
 

Online Macbeth

  • Super Contributor
  • ***
  • Posts: 2498
  • Country: gb
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #13 on: July 08, 2016, 02:44:58 pm »
I am in awe of the new DaveCAD transparent animation plugin. Patent it before Solidworks steal it for themselves!  :-+
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 9139
  • Country: au
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #14 on: July 08, 2016, 03:33:09 pm »
Sorry I didn't comment earlier, but I, too, was impressed by the animation plugin!

Looks like it can handle multiple layers as well.  Impressive.
 

Offline Hootch

  • Contributor
  • Posts: 16
  • Country: de
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #15 on: July 08, 2016, 03:44:02 pm »
Big announcement video coming shortly, I've sold DaveCAD to a large CAD company who shall remain nameless right now. Will post it from my new private island.
You just revealed it: 3M  :)
 

Offline rrinker

  • Super Contributor
  • ***
  • Posts: 1862
  • Country: us
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #16 on: July 08, 2016, 06:16:29 pm »
Dave made a demo of the Davecad V2.0 in this video, with animation features !
Innovation in the CAD field :)
I hope this V2.0 will be released soon :)

Big announcement video coming shortly, I've sold DaveCAD to a large CAD company who shall remain nameless right now. Will post it from my new private island.

 Altium owned an ISLAND, too?

 

Offline Howardlong

  • Super Contributor
  • ***
  • Posts: 4709
  • Country: gb
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #17 on: July 10, 2016, 04:58:42 pm »
39k on my two units, 20k was an improvement, but 39k much better.
 

Offline BobC

  • Supporter
  • ****
  • Posts: 115
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #18 on: July 10, 2016, 08:27:57 pm »
Trap for Young Players:  When purchasing a device for outdoor use, always take it outdoors and view it while wearing your polarized sunglasses!

Way too many displays need to be turned sideways to be legible when wearing polarized glasses. I haven't seen the problem in my recent multimeters, but it was present in some older ones.

The first Android phone I purchased, an LG L9, worked great outdoors at all orientations (I still need to figure out how they pulled that one off).  But I forgot to check my next phone, a Samsung Galaxy Avant, and it turned out to be viewable only in portrait orientation, which fortunately works fine for Google Maps, but not for any of my fitness tracking apps.  Arrgh!
 

Offline amyk

  • Super Contributor
  • ***
  • Posts: 6413
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #19 on: July 11, 2016, 01:44:24 am »
Trap for Young Players:  When purchasing a device for outdoor use, always take it outdoors and view it while wearing your polarized sunglasses!

Way too many displays need to be turned sideways to be legible when wearing polarized glasses. I haven't seen the problem in my recent multimeters, but it was present in some older ones.

The first Android phone I purchased, an LG L9, worked great outdoors at all orientations (I still need to figure out how they pulled that one off).  But I forgot to check my next phone, a Samsung Galaxy Avant, and it turned out to be viewable only in portrait orientation, which fortunately works fine for Google Maps, but not for any of my fitness tracking apps.  Arrgh!
That's because some of them use 45-degree polarisation while others are 0/90.

http://electronics.stackexchange.com/questions/28113/why-are-lcd-panels-polarized-at-45-degrees

And of course those using OLED will be visible at any angle.
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 9139
  • Country: au
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #20 on: July 11, 2016, 03:10:55 am »
Trap for Young Players:  When purchasing a device for outdoor use, always take it outdoors and view it while wearing your polarized sunglasses!

Way too many displays need to be turned sideways to be legible when wearing polarized glasses. I haven't seen the problem in my recent multimeters, but it was present in some older ones.

Yes, the polarization experiment needs to be done before purchase.


An aside.... I remember walking down the street one day wearing my polarized sunnies when I spotted a woman walking in the opposite direction wearing hers.  The only trouble was, with her glasses one lens was clear and the other was black and a quick tilt of my head confirmed hers were polarizing.  I expect one of the lenses had been put in 90º out of whack - which was possible because they were perfectly circular.  I wonder if she ever had a glare problem with her left eye.......
 

Offline amyk

  • Super Contributor
  • ***
  • Posts: 6413
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #21 on: July 11, 2016, 10:23:34 am »
Trap for Young Players:  When purchasing a device for outdoor use, always take it outdoors and view it while wearing your polarized sunglasses!

Way too many displays need to be turned sideways to be legible when wearing polarized glasses. I haven't seen the problem in my recent multimeters, but it was present in some older ones.

Yes, the polarization experiment needs to be done before purchase.


An aside.... I remember walking down the street one day wearing my polarized sunnies when I spotted a woman walking in the opposite direction wearing hers.  The only trouble was, with her glasses one lens was clear and the other was black and a quick tilt of my head confirmed hers were polarizing.  I expect one of the lenses had been put in 90º out of whack - which was possible because they were perfectly circular.  I wonder if she ever had a glare problem with her left eye.......
She'd probably see the same thing and wonder why your glasses had the lenses wrong...
 

Offline LazyJack

  • Regular Contributor
  • *
  • Posts: 164
  • Country: hu
  • Keep calm, I've got the situation under control.
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #22 on: July 11, 2016, 10:35:38 am »
Trap for Young Players:  When purchasing a device for outdoor use, always take it outdoors and view it while wearing your polarized sunglasses!

Way too many displays need to be turned sideways to be legible when wearing polarized glasses. I haven't seen the problem in my recent multimeters, but it was present in some older ones.

The first Android phone I purchased, an LG L9, worked great outdoors at all orientations (I still need to figure out how they pulled that one off).  But I forgot to check my next phone, a Samsung Galaxy Avant, and it turned out to be viewable only in portrait orientation, which fortunately works fine for Google Maps, but not for any of my fitness tracking apps.  Arrgh!

Yeah! Trap indeed. This is something a lot of marine instrument manufacturers still need to learn. On my boat, when wearing polarizing sunglasses (practically all the time, when it's not dark around) I need to constantly tilt my head back and forth to either see the depth sounder or the autopilot display.
But I've been to cars, where various displays, like radio and A/C did not have the same polarization, so one of them was always black in polar glasses.
 

Offline bktemp

  • Super Contributor
  • ***
  • Posts: 1623
  • Country: de
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #23 on: July 11, 2016, 11:08:27 am »
And of course those using OLED will be visible at any angle.
For OLEDs itself this is true, but there are sometimes polarizers added to the display to reduce glare.
 

Offline Brumby

  • Supporter
  • ****
  • Posts: 9139
  • Country: au
Re: EEVblog #898 - LCD Contrast Experiments
« Reply #24 on: July 11, 2016, 12:43:10 pm »
Trap for Young Players:  When purchasing a device for outdoor use, always take it outdoors and view it while wearing your polarized sunglasses!

Way too many displays need to be turned sideways to be legible when wearing polarized glasses. I haven't seen the problem in my recent multimeters, but it was present in some older ones.

Yes, the polarization experiment needs to be done before purchase.


An aside.... I remember walking down the street one day wearing my polarized sunnies when I spotted a woman walking in the opposite direction wearing hers.  The only trouble was, with her glasses one lens was clear and the other was black and a quick tilt of my head confirmed hers were polarizing.  I expect one of the lenses had been put in 90º out of whack - which was possible because they were perfectly circular.  I wonder if she ever had a glare problem with her left eye.......
She'd probably see the same thing and wonder why your glasses had the lenses wrong...

Not sure about that.  Her left eye would see my glasses as being black on both sides and her right would see them as clear.  With binocular vision, these two images would be overlaid in the brain and the problem would not be immediately obvious.

Her left eye, however, would not have been getting the protection of polarizing filtering in the normal plane.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf