Author Topic: Screen Display Energy Efficiency  (Read 1553 times)

Offline yesitsme

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Screen Display Energy Efficiency
« on: August 19, 2016, 12:28:16 PM »
In what state is the screen using the least energy, and where does it waste most of its energy.

In general there are three types of screens, 1CRT, 2LCD (Led, CCFL [Baklight]), 3OLED (PMOLED, AMOLED, Super AMOLED)

CRT retired not going to write about consumes the most energy compared to others horrible resolution,

LCD stands for Liquid Crystal Display the lcd responsibilityto is produce the colors when its not charges (No Voltage) it's transparent when it's fully charged it's opaque (Black) if there would be no backlight you would see black on black (Deep black) And red on black there fore there's a backlight that lights up the back of the lcd so you can actuly see the color of the lcd (Every pixel has 3 subpixels one for red one for green and one for blue [R,G,B])

LCD the most energy consuming is the back light, the rest goes for the LCD when the screen is black the backlight is the same bright as it always would Plus it has to charge both  electrodes (Vertical + Horizontal) to block the Backlight.

There are two choices of backlight source one is CCFL fluorescent And LED, Led is obviously more efficient.
Color White is more efficient since it essentially means transparent it doesnt have to charge those pixels.

LCD screens cant produce true (Deep) Black since it has a backlight shining from behind it, therefore dynamic contrast ratio came into play it would dim the backlight of a particular section of the screen if there's no color needed in that section LCD = Black, Backlight = Black(Dim) you got true black color.
for screens that have a dynamic contrast ratio having a black background might save some energy.


Summary LCD to save energy
  • Led Backlight
  • lower the brightness as much posible,
  • depending on your screen type white/black background, (native contrast ratio white background, dynamic contrast ratio Black Background)


OLED organic light-emitting diode, to be continued........
 Instead of making light by heating a wire filament till it glows white hot (which is how a normal lamp works),An OLED is simply an LED where the light is produced ("emitted") by organic molecules, Organic molecules are simply ones based around lines or rings of carbon atoms, including such common things as sugar, gasoline, alcohol, wood, and plastics.

I don't want to get to technical, the bottom line is that oled screen doesnt need a backlight every pixel can produce light therefore to produce a black color the pixel and its subset are off and you get a deep true black and there's no energy used for those pixels,  OLEDs use power as a function of the specific image being displayed. Dark images consume small amounts of power while light or white images consume maximum power, if you noticed the recent android battery saver mode set a black background  to save energy,

Summary
  • set your bakground black



« Last Edit: August 19, 2016, 03:31:09 PM by yesitsme »

Offline yesitsme

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Re: Screen Display Energy Efficiency
« Reply #1 on: August 19, 2016, 04:16:28 PM »
Intresting to note that all colors are made out of Red Green Blue, The secondary colors of RGB, cyan, magenta, and yellow, are formed by the mixture of two of the primaries and the exclusion of the third. Red and green combine to make yellow, green and blue make cyan, blue and red make magenta. The combination of red, green, and blue in full intensity makes white.

If you are a developer or a graphic designer you probably know that by now.

http://www.livescience.com/17948-red-green-blue-yellow-stunning-colors.html
« Last Edit: August 19, 2016, 04:20:40 PM by yesitsme »

Offline yesitsme

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Re: Screen Display Energy Efficiency
« Reply #2 on: August 19, 2016, 04:21:37 PM »
Intresting to note that all colors are made out of Red Green Blue, The secondary colors of RGB, cyan, magenta, and yellow, are formed by the mixture of two of the primaries and the exclusion of the third. Red and green combine to make yellow, green and blue make cyan, blue and red make magenta. The combination of red, green, and blue in full intensity makes white.

If you are a developer or a graphic designer you probably know that by now.

http://www.livescience.com/17948-red-green-blue-yellow-stunning-colors.html
The main point i left out i guess it will wait till after shaboss.

Offline yesitsme

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Re: Screen Display Energy Efficiency
« Reply #3 on: August 21, 2016, 02:40:32 AM »
This is the layout of a standard lcd screen

as you see every pixel is made of three subpixels R,G,B,
Our brain interprets these colors and mixes them into purple, yellow, orange, brown, etc, which is what we "see", our eyes have three kinds of cone cells, red sensitive, green sensitive, and blue sensitive, a three color display can trigger the same cone cells in the viewers eyes, in the same combination and degree as a spectral color,

"Violet" light actually triggers the red cones in your eyes in addition to  the blue, and for that reason the color violet can be represented on a monitor with a bit of red and mostly blue, for instance, RGB(50,0,255)...which would give it some "purplyness".
« Last Edit: August 21, 2016, 02:54:55 AM by yesitsme »

Offline yesitsme

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Re: Screen Display Energy Efficiency
« Reply #4 on: August 21, 2016, 03:23:08 AM »
Super AMOLED is a version of AMOLED display technology that integrates a capacitive touchscreen layer directly into the display instead of overlaying it on top of the display, as has traditionally been done.

This results in a thinner design that uses less power and reflects less light, and as a result works better outdoors.

Super Amoled uses the "PenTile matrix", The basic PenTile structure is the RGBG matrix, In RGBG PenTile displays there are only two subpixels per pixel, with twice as many green pixels than red and blue ones, Unlike the image above the standard lcd rgb subpixel layout,
PenTile relies on the human eye design it uses green subpixels as base, since the human eye is most sensitive to that color when bright, and then alternates between blue and red ones,
In Short each pixel is combied of 2 subpixels 1 green and the other either green or blue, Saves enery same quality looks brighter.
 
Super Amoled Plus
used for Galaxy S II, they dropped the PenTile Matrix and went to rgb stripe as showen above (Samsung Discontinued using this structure).
« Last Edit: August 21, 2016, 03:55:14 AM by yesitsme »

Offline yesitsme

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Re: Screen Display Energy Efficiency
« Reply #5 on: August 21, 2016, 03:57:19 AM »
PMOLED (Passive Matrix) vs AMOLED (Active matrix)- what's the difference?

Every screen has a matrix addressing system that changes the pixels (Refreshes the screen) usually a rate of 60hz =60 times per second,

The term AMOLED means Active-Matrix OLED. The 'active-matrix' part refers to the driving electronics, or the TFT layer. When you display an image, you actually display it line by line (sequentially) as you can only change one line at a time. An AMOLED uses a TFT which contains a storage capacitor which maintains the line pixel states, and so enables large size (and large resolution) displays, and have no restriction on size or resolution.

PMOLED electronics do not contain a storage capacitor and so the pixels in each line are actually off most of the time. To compensate for this you need to use more voltage to make them brighter. If you have 10 lines, for example, you have to make the one line that is on 10 times as bright (the real number is less then 10, but that's the general idea).

So while PMOLEDs are easy (and cheap) to fabricate, they are not efficient and the OLED materials suffer from lower lifetime (due to the high voltage needed). PMOLED displays are also restricted in resolution and size (the more lines you have, the more voltage you have to use). PMOLED displays are usually small (up to 3" typically) and are used to display character data or small icons: they are being used in MP3 players, mobile phone sub displays, etc.
« Last Edit: August 21, 2016, 04:46:12 AM by yesitsme »

Offline yesitsme

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Re: Screen Display Energy Efficiency
« Reply #6 on: August 21, 2016, 05:05:12 AM »
As noted above that screens with dynamic contrast ratio save energy displaying black areas on the screen, ther's a movement  #Blackscreensmatter that wants we should all have black backgrounds they made a Black google search in response the WSJ published a article questioning the effectiveness of a black background (Note this argument is only for LCD screens, Oled screens it's definitely effective)

Offline yakov116

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Re: Screen Display Energy Efficiency
« Reply #7 on: August 23, 2016, 09:41:33 PM »
In what state is the screen using the least energy, and where does it waste most of its energy.

In general there are three types of screens, 1CRT, 2LCD (Led, CCFL [Baklight]), 3OLED (PMOLED, AMOLED, Super AMOLED)

CRT retired not going to write about consumes the most energy compared to others horrible resolution,

LCD stands for Liquid Crystal Display the lcd responsibilityto is produce the colors when its not charges (No Voltage) it's transparent when it's fully charged it's opaque (Black) if there would be no backlight you would see black on black (Deep black) And red on black there fore there's a backlight that lights up the back of the lcd so you can actuly see the color of the lcd (Every pixel has 3 subpixels one for red one for green and one for blue [R,G,B])

LCD the most energy consuming is the back light, the rest goes for the LCD when the screen is black the backlight is the same bright as it always would Plus it has to charge both  electrodes (Vertical + Horizontal) to block the Backlight.

There are two choices of backlight source one is CCFL fluorescent And LED, Led is obviously more efficient.
Color White is more efficient since it essentially means transparent it doesnt have to charge those pixels.

LCD screens cant produce true (Deep) Black since it has a backlight shining from behind it, therefore dynamic contrast ratio came into play it would dim the backlight of a particular section of the screen if there's no color needed in that section LCD = Black, Backlight = Black(Dim) you got true black color.
for screens that have a dynamic contrast ratio having a black background might save some energy.


Summary LCD to save energy
  • Led Backlight
  • lower the brightness as much posible,
  • depending on your screen type white/black background, (native contrast ratio white background, dynamic contrast ratio Black Background)


OLED organic light-emitting diode, to be continued........
 Instead of making light by heating a wire filament till it glows white hot (which is how a normal lamp works),An OLED is simply an LED where the light is produced ("emitted") by organic molecules, Organic molecules are simply ones based around lines or rings of carbon atoms, including such common things as sugar, gasoline, alcohol, wood, and plastics.

I don't want to get to technical, the bottom line is that oled screen doesnt need a backlight every pixel can produce light therefore to produce a black color the pixel and its subset are off and you get a deep true black and there's no energy used for those pixels,  OLEDs use power as a function of the specific image being displayed. Dark images consume small amounts of power while light or white images consume maximum power, if you noticed the recent android battery saver mode set a black background  to save energy,

Summary
  • set your bakground black




Intresting to note that all colors are made out of Red Green Blue, The secondary colors of RGB, cyan, magenta, and yellow, are formed by the mixture of two of the primaries and the exclusion of the third. Red and green combine to make yellow, green and blue make cyan, blue and red make magenta. The combination of red, green, and blue in full intensity makes white.

If you are a developer or a graphic designer you probably know that by now.

http://www.livescience.com/17948-red-green-blue-yellow-stunning-colors.html

The main point i left out i guess it will wait till after shaboss.
PMOLED (Passive Matrix) vs AMOLED (Active matrix)- what's the difference?

Every screen has a matrix addressing system that changes the pixels (Refreshes the screen) usually a rate of 60hz =60 times per second,

The term AMOLED means Active-Matrix OLED. The 'active-matrix' part refers to the driving electronics, or the TFT layer. When you display an image, you actually display it line by line (sequentially) as you can only change one line at a time. An AMOLED uses a TFT which contains a storage capacitor which maintains the line pixel states, and so enables large size (and large resolution) displays, and have no restriction on size or resolution.

PMOLED electronics do not contain a storage capacitor and so the pixels in each line are actually off most of the time. To compensate for this you need to use more voltage to make them brighter. If you have 10 lines, for example, you have to make the one line that is on 10 times as bright (the real number is less then 10, but that's the general idea).

So while PMOLEDs are easy (and cheap) to fabricate, they are not efficient and the OLED materials suffer from lower lifetime (due to the high voltage needed). PMOLED displays are also restricted in resolution and size (the more lines you have, the more voltage you have to use). PMOLED displays are usually small (up to 3" typically) and are used to display character data or small icons: they are being used in MP3 players, mobile phone sub displays, etc.

As noted above that screens with dynamic contrast ratio save energy displaying black areas on the screen, ther's a movement  #Blackscreensmatter that wants we should all have black backgrounds they made a Black google search in response the WSJ published a article questioning the effectiveness of a black background (Note this argument is only for LCD screens, Oled screens it's definitely effective)

Wow wow thanks for this great post(s)
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Offline grodnoking

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Re: Screen Display Energy Efficiency
« Reply #8 on: August 23, 2016, 10:11:37 PM »
I keep tapatalk in night mode all day. I'm pretty sure it helps a ton.
I'm not who you think I am.

Offline yakrot

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Re: Screen Display Energy Efficiency
« Reply #9 on: August 23, 2016, 10:44:58 PM »
I keep tapatalk in night mode all day. I'm pretty sure it helps a ton.
I can't read it in daytime mode way easier to read in night mode. Only time I switched back was to read sf's tr on Iceland the blue words are hard to read in night mode