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Quoth · 01-10-2021, 09:55 AM

LCDs don't actually work at all without polarising layers. Nothing to do with glare. The crystal like molecules of the liquid are thread like and have opposite charges, overall neutral, at the ends. Thus with an electric field via transparent electrodes they polarize light. If the rear is fed with polarised light, usually a polarised film on the rear glass, and a second polarising film is on the front glass, then the area between each pair of transparent electrodes, on the inside of front and rear, goes dark or clear as the field is changed. You have to use AC, because DC would cause electrolytic decomposition of the liquid. This is and the back light are the main power loss. The back polariser and lamp can be replaced with a mirror. Or a partial mirror can be between the polariser and glass at the rear.
Colour is achieved by using three dots in line and coloured stripes, or a 2 x 2 pattern of
R G
G B
dots. Or other more complex layouts.
Simple displays use external electronics. Graphics panels above a certain resolution use thin film transistors on part of each dot driving the transparent electrode. The display may be in two halves or four quarters to reduce the duty cycle of the rows and columns. Larger displays have additional multiplexing row and column driver chips on the edges of the glass.

The layers and the polarising aspect of operation limit the viewing angle. Colour shifts due to glass thickness and the wrong filter colour over a dot at shallow angles. The contrast varies with viewing angle, related to thickness of liquid, angle of polarising films, drive voltage and drive waveform.

Even a large display with very few elements that's not using multiplexed drive takes hardly any power, thus a coin cell can run it for a couple of years. The AC nature coupled with multiplexing of millions of dots, x3 to x5 per pixel in colour, dramatically increases the power consumption. But in sunlight, or for a 55" TV in a bright room, most of the power is for the backlight. Due to loss in the polarising filters, colour filters and liquid, a purely reflective colour display needs very bright sunshine. The N9210 Smartphone used CCFL tubes and a high voltage for the backlight, the N9210i later in 2002 used LED backlighting. Even in 2014 a CCFL backlit LCD TV gave better even illumination and colour than edge fed LED backlights on LCDs.

https://en.wikipedia.org/wiki/Liquid..._field_effects
See also https://en.wikipedia.org/wiki/Kerr_effect and https://en.wikipedia.org/wiki/Faraday_effect

Most users of laptops, PC displays, tablets and phones have them far too bright indoors.

Colour CRTs were not an eyestrain issue when properly adjusted. Mono green or Amber or even white CRTs were not an issue if properly adjusted. Other issues were the resolution (either too low on screen or too high on graphics setting), interlace flicker and the wrong viewing distance for regular reading distance glasses. Or people that needed glasses to read refusing to wear them for the computer.

Also today you can't use much more than 17" to 19" with reading glasses at the proper distance without having to move your head. A 21" to 37" screen at reading distance with glasses exceeds the viewing area.

01-10-2021, 09:55 AM	#26
Quoth Still reading Posts: 14,509 Karma: 108666825 Join Date: Jun 2017 Location: Ireland Device: All 4 Kinds: epub eink, Kindle, android eink, NxtPaper	LCDs don't actually work at all without polarising layers. Nothing to do with glare. The crystal like molecules of the liquid are thread like and have opposite charges, overall neutral, at the ends. Thus with an electric field via transparent electrodes they polarize light. If the rear is fed with polarised light, usually a polarised film on the rear glass, and a second polarising film is on the front glass, then the area between each pair of transparent electrodes, on the inside of front and rear, goes dark or clear as the field is changed. You have to use AC, because DC would cause electrolytic decomposition of the liquid. This is and the back light are the main power loss. The back polariser and lamp can be replaced with a mirror. Or a partial mirror can be between the polariser and glass at the rear. Colour is achieved by using three dots in line and coloured stripes, or a 2 x 2 pattern of R G G B dots. Or other more complex layouts. Simple displays use external electronics. Graphics panels above a certain resolution use thin film transistors on part of each dot driving the transparent electrode. The display may be in two halves or four quarters to reduce the duty cycle of the rows and columns. Larger displays have additional multiplexing row and column driver chips on the edges of the glass. The layers and the polarising aspect of operation limit the viewing angle. Colour shifts due to glass thickness and the wrong filter colour over a dot at shallow angles. The contrast varies with viewing angle, related to thickness of liquid, angle of polarising films, drive voltage and drive waveform. Even a large display with very few elements that's not using multiplexed drive takes hardly any power, thus a coin cell can run it for a couple of years. The AC nature coupled with multiplexing of millions of dots, x3 to x5 per pixel in colour, dramatically increases the power consumption. But in sunlight, or for a 55" TV in a bright room, most of the power is for the backlight. Due to loss in the polarising filters, colour filters and liquid, a purely reflective colour display needs very bright sunshine. The N9210 Smartphone used CCFL tubes and a high voltage for the backlight, the N9210i later in 2002 used LED backlighting. Even in 2014 a CCFL backlit LCD TV gave better even illumination and colour than edge fed LED backlights on LCDs. https://en.wikipedia.org/wiki/Liquid..._field_effects See also https://en.wikipedia.org/wiki/Kerr_effect and https://en.wikipedia.org/wiki/Faraday_effect Most users of laptops, PC displays, tablets and phones have them far too bright indoors. Colour CRTs were not an eyestrain issue when properly adjusted. Mono green or Amber or even white CRTs were not an issue if properly adjusted. Other issues were the resolution (either too low on screen or too high on graphics setting), interlace flicker and the wrong viewing distance for regular reading distance glasses. Or people that needed glasses to read refusing to wear them for the computer. Also today you can't use much more than 17" to 19" with reading glasses at the proper distance without having to move your head. A 21" to 37" screen at reading distance with glasses exceeds the viewing area.