Scoob
New member
Hi all,
Quite some time back I was looking at changing my monitor, so started trying to swat up on the different ones available as you do. Initially I didn’t even know there were different panel types such as TN, IPS and VA but I found out a lot through reading. Since my initial research the LED LCD panel has become more common, so that’s yet another variable to add when looking!
The basics
All flat-screen monitors look to be basically the same, i.e there is some sort of light source, this light will then pass through lcd “shutters” of which there are several per-displayed pixel. This is because the light next goes through the RGB colour filter resulting in the image we see. The degree to which these shutters are open dictates how much of the light gets through and how the RGB mixes to give the final colour.
The LCD sheet is basically sandwiched between two oppositely polarised pieces of glass. Naturally, due to the opposite polarisation, the light will pass through the first filter but not get through the second and to the display we see. The crystals (in the Liquid Crystal Display) effectively change the orientation on the light passing through them to match the polarisation of the second filter so a certain amount of the light can get through.
Different Types of Panel
There are different types of LCD panels, these are the three main ones:
TN – Twisted Nematic
The liquid crystals in this type of display are stacked on top of one another in twisted spiral-like shape. When there is no power present light will travel through the first filter, having its polarisation changed by the liquid crystal so it gets through the 2nd panel – this would result in a pure white (from the lightsource) pixel being displayed. When an electrical change is applied the polarisation is changed as the liquid crystal stack straightens so the light cannot get through, resulting in a black pixel. If the level of voltage applied is varied, so does the amount of light “blocked” allowing the colour variations we see.
Pro: Cheaper to produce generally with a good response time, meaning a panel based on this tech would be less likely to be subject to ghosting. Ideal for a gaming panel.
Con: Lower contrast ratio than other panel types and the viewing angle is poor. Some even report a degree of colour distortion at the edges of the screen. TN tech also cannot display the full 16.7 million colours (8 bit RGB) rather “just” 262,144 (6 bit RGB) Dithering is used to make it look like the full range is available. However many cannot notice this limitation.
IPS – In-Plane Switching
The liquid crystals in this type of display are stacked on top of each other and aligned parallel to the filters. When no power is present the polarity of the light is unchanged so cannot get through the second filter, resulting in a black spot. Applying voltage will change the polarity giving a white spot. Again, changing the voltage will vary the amount of RGB light that gets through, colouring the pixel accordingly.
Pro: Excellent contrast ratio and viewing angles and can display the full 16.7 million colours (24bit, 8bit RGB)
Con: More expensive, slower response speed, potentially resulting ghosting issues – more suited to desktop graphical work rather than gaming, though faster IPS displays are available – at a cost.
VA – Vertical Alignment
The liquid crystals in this type of display are lined up perpendicularly to the filters. Other than that it appears to be the same as an IPS panel with no light being allowed through when no voltage is present.
Pro: Better contrast and viewing angles than TN, while being cheaper and faster than IPS.
Con: Not quite the quality of a good IPS panel and not quite the response of a good TN panel.
“LED” Panels
The “LED” in an LED display just refers to the method used for the backlight. In older designs the light is provided by one or more conventional bulbs. These are not so efficient and generate a fair bit of heat. All my LCD monitors get quite warm to the touch, especially the older ones, as does my first gen LCD TV… I’d not be surprised if it heated the room more than the PC that I’ve got plugged into it!
With an LED backlight there is far less waste heat, so they are much more power efficient. An LED backlight in effect provides a grid of lights behind the display so, in theory, the level of brightness should be more even across the display.
Interestingly there are both white and coloured LED backlights. White would rely on the LCD “shutter” and RGB colour filter to produce the desired colour. A coloured LED would produce the colour directly, thus simplifying the LCD display… not something I really researched, but check out “OLED” displays further down.
Some terms of interest
Contrast Ratio: simply the difference between the monitors attempt at a totally black vs. a totally white pixel.
Dynamic Contrast: Here the monitor tries to be clever, so if the displayed image is “mostly” dark, it will lower the brightness of the backlight to produce an overall darker imagine. This can be good as you’d experience less light bleeding and darker blacks. The opposite is true for a particularly bright scene, in that the backlight will be turned up. Sounds good in theory, but can look bad. I think the “true” contrast ratio is more important here.
Response Time: the time it takes for a pixel to go from black to white and back to black. In real terms a pixel is more likely to be asked to go from a colour to a colour, i.e. not an absolute. This is known as grey to grey and can take a fair bit longer. A good grey to grey time is important for a gaming monitor, though only some manufacturers give this figure. However, if your monitor can do 2ms black to black then it should be pretty damn good at grey to grey. My 10 year old Iiyama LCD, which is connected to my gateway PC and mainly used for surfing, has a very low 30-something ms response time. As such, while I can game on it, I see a lot of ghosting. As I do when I game on my LCD TV with it’s 20-something ms response time.
OLED: Further to the above on LED backlights there’s also the “OLED” Organic LED. This type of tech has each pixel generating the coloured light directly, rather than filtering it. It gives very good image quality and low power usage – more common on modern smart phones and cameras. Didn’t exist when I did my initial research for any available monitor, though I understand some laptops have this now. Still an expensive tech, but an exciting one.
Summing up
This post is intended to be very much a high-level laymans guide and, like most subjects, there’s far more to this than I’ve said here. This is the level of information that was of use to ME when I was looking, and doubtless will be again if I look again for another screen. My information comes from a variety of googled sources and knowing what exactly I got from where is a mystery to me now. Hopefully it’ll provide enough initial information for someone to make a better monitor choice, as it did me, or at least understand why their TN panel was such a steal vs. another IPS one
For the record I picked up a fairly cheap LG “LN” panel myself for gaming. Despite all my research into the different types it was a special offer which (at the time) was a VERY good price that got me. Lol. I’ve been more than happy with this display and none of the down-sides of a TN panel have troubled me. It’s black reproduction is fine (not perfect) the colours seem quite vibrant even if it cannot display them all “properly” and I benefit from a good response time in gaming. I’ve seen monitors that look sharper with more vibrant colours, but they were a LOT more pricey.
One final thing, to the best of my knowledge my information is accurate, however it did all come from the internet and was in turn parsed by my brain, so please if anyone spots any mistakes please let me know & I can update both my notes and this post.
Cheers,
Scoob.
Quite some time back I was looking at changing my monitor, so started trying to swat up on the different ones available as you do. Initially I didn’t even know there were different panel types such as TN, IPS and VA but I found out a lot through reading. Since my initial research the LED LCD panel has become more common, so that’s yet another variable to add when looking!
The basics
All flat-screen monitors look to be basically the same, i.e there is some sort of light source, this light will then pass through lcd “shutters” of which there are several per-displayed pixel. This is because the light next goes through the RGB colour filter resulting in the image we see. The degree to which these shutters are open dictates how much of the light gets through and how the RGB mixes to give the final colour.
The LCD sheet is basically sandwiched between two oppositely polarised pieces of glass. Naturally, due to the opposite polarisation, the light will pass through the first filter but not get through the second and to the display we see. The crystals (in the Liquid Crystal Display) effectively change the orientation on the light passing through them to match the polarisation of the second filter so a certain amount of the light can get through.
Different Types of Panel
There are different types of LCD panels, these are the three main ones:
TN – Twisted Nematic
The liquid crystals in this type of display are stacked on top of one another in twisted spiral-like shape. When there is no power present light will travel through the first filter, having its polarisation changed by the liquid crystal so it gets through the 2nd panel – this would result in a pure white (from the lightsource) pixel being displayed. When an electrical change is applied the polarisation is changed as the liquid crystal stack straightens so the light cannot get through, resulting in a black pixel. If the level of voltage applied is varied, so does the amount of light “blocked” allowing the colour variations we see.
Pro: Cheaper to produce generally with a good response time, meaning a panel based on this tech would be less likely to be subject to ghosting. Ideal for a gaming panel.
Con: Lower contrast ratio than other panel types and the viewing angle is poor. Some even report a degree of colour distortion at the edges of the screen. TN tech also cannot display the full 16.7 million colours (8 bit RGB) rather “just” 262,144 (6 bit RGB) Dithering is used to make it look like the full range is available. However many cannot notice this limitation.
IPS – In-Plane Switching
The liquid crystals in this type of display are stacked on top of each other and aligned parallel to the filters. When no power is present the polarity of the light is unchanged so cannot get through the second filter, resulting in a black spot. Applying voltage will change the polarity giving a white spot. Again, changing the voltage will vary the amount of RGB light that gets through, colouring the pixel accordingly.
Pro: Excellent contrast ratio and viewing angles and can display the full 16.7 million colours (24bit, 8bit RGB)
Con: More expensive, slower response speed, potentially resulting ghosting issues – more suited to desktop graphical work rather than gaming, though faster IPS displays are available – at a cost.
VA – Vertical Alignment
The liquid crystals in this type of display are lined up perpendicularly to the filters. Other than that it appears to be the same as an IPS panel with no light being allowed through when no voltage is present.
Pro: Better contrast and viewing angles than TN, while being cheaper and faster than IPS.
Con: Not quite the quality of a good IPS panel and not quite the response of a good TN panel.
“LED” Panels
The “LED” in an LED display just refers to the method used for the backlight. In older designs the light is provided by one or more conventional bulbs. These are not so efficient and generate a fair bit of heat. All my LCD monitors get quite warm to the touch, especially the older ones, as does my first gen LCD TV… I’d not be surprised if it heated the room more than the PC that I’ve got plugged into it!
With an LED backlight there is far less waste heat, so they are much more power efficient. An LED backlight in effect provides a grid of lights behind the display so, in theory, the level of brightness should be more even across the display.
Interestingly there are both white and coloured LED backlights. White would rely on the LCD “shutter” and RGB colour filter to produce the desired colour. A coloured LED would produce the colour directly, thus simplifying the LCD display… not something I really researched, but check out “OLED” displays further down.
Some terms of interest
Contrast Ratio: simply the difference between the monitors attempt at a totally black vs. a totally white pixel.
Dynamic Contrast: Here the monitor tries to be clever, so if the displayed image is “mostly” dark, it will lower the brightness of the backlight to produce an overall darker imagine. This can be good as you’d experience less light bleeding and darker blacks. The opposite is true for a particularly bright scene, in that the backlight will be turned up. Sounds good in theory, but can look bad. I think the “true” contrast ratio is more important here.
Response Time: the time it takes for a pixel to go from black to white and back to black. In real terms a pixel is more likely to be asked to go from a colour to a colour, i.e. not an absolute. This is known as grey to grey and can take a fair bit longer. A good grey to grey time is important for a gaming monitor, though only some manufacturers give this figure. However, if your monitor can do 2ms black to black then it should be pretty damn good at grey to grey. My 10 year old Iiyama LCD, which is connected to my gateway PC and mainly used for surfing, has a very low 30-something ms response time. As such, while I can game on it, I see a lot of ghosting. As I do when I game on my LCD TV with it’s 20-something ms response time.
OLED: Further to the above on LED backlights there’s also the “OLED” Organic LED. This type of tech has each pixel generating the coloured light directly, rather than filtering it. It gives very good image quality and low power usage – more common on modern smart phones and cameras. Didn’t exist when I did my initial research for any available monitor, though I understand some laptops have this now. Still an expensive tech, but an exciting one.
Summing up
This post is intended to be very much a high-level laymans guide and, like most subjects, there’s far more to this than I’ve said here. This is the level of information that was of use to ME when I was looking, and doubtless will be again if I look again for another screen. My information comes from a variety of googled sources and knowing what exactly I got from where is a mystery to me now. Hopefully it’ll provide enough initial information for someone to make a better monitor choice, as it did me, or at least understand why their TN panel was such a steal vs. another IPS one
For the record I picked up a fairly cheap LG “LN” panel myself for gaming. Despite all my research into the different types it was a special offer which (at the time) was a VERY good price that got me. Lol. I’ve been more than happy with this display and none of the down-sides of a TN panel have troubled me. It’s black reproduction is fine (not perfect) the colours seem quite vibrant even if it cannot display them all “properly” and I benefit from a good response time in gaming. I’ve seen monitors that look sharper with more vibrant colours, but they were a LOT more pricey.
One final thing, to the best of my knowledge my information is accurate, however it did all come from the internet and was in turn parsed by my brain, so please if anyone spots any mistakes please let me know & I can update both my notes and this post.
Cheers,
Scoob.
