pelvis_3
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TFT/CRT Brief
I’ll primarily be focusing TFT displays but there is a few mentions of CRT displays. Basically this is to just explain a few of the main points to buying a monitor. The There are a number of questions asked about TFT/LCD screens, and I will try my best to explain them. The most common are below:
With monitors, when measuring the size of the screen, there are some things to look for. For instance a 17" CRT monitor only has 15.5" visible. With TFT monitors, a 17" monitor has 17" viewable. Therefor a 15" TFT monitor is equivalent to a 17" CRT and a 17" TFT = 19" CRT etc and so on.
TFT displays are usually designed to run at a specific resolution (native resolution). Most 15" TFT displays are designed to run at 1024x768 @ 75Hz. 17” TFT’s run at 1280x1024 @ 75Hz and so on. Although you can use smaller displays like 800x600 but the fonts can look out of proportion and pixelated. Before purchasing it is worth checking that you are happy with this resolution.
Advantages of TFT displays:
1.There is much less glare from a TFT monitor.
2.The monitor is far less bulky. This has a couple of advantages, firstly it gives you more desk space, but secondly because of this you can position the monitor further away from you which most people find more comfortable on the eyes.
3.TFT monitors produce less heat and radiation that CRT monitors.
4.TFT monitors have a very crisp image only comparable to very expensive CRT monitors.
5.The monitor (so long as it is VESA compliant) can be mounted on an arm or on the wall to save even more desk space.
Disadvantages of TFT displays:
1.If you are working with graphics, although the graphics are very clear, due to the limited angle at which you can view the display colours may appear slightly different on non-TFT screens.
2.TFT monitors have a limited angle of view. This is the angle at which you can clearly view the screen. If you are looking directly at the screen while working on your PC this is fine, but if others are trying to read it then they may have difficulty (try looking at a laptop screen from a 45 degree angle).
3.You may experience some blurring on lower end models when there is movement on the screen. This is most prominent in full screen games where you get a motion blur effect but is also noticeable when scrolling through documents or websites.
CRT advantages
1.Accurate color:
CRTs can provide richer color in a fuller spectrum than most LCDs. In general, graphic artists prefer CRT monitors because they show truer colors and greater nuance-particularly useful for preparing files for printing and for using photo applications such as Adobe® Photoshop®.
2.Response time:
CRTs may respond more quickly than some LCDs to videos and fast-action games. For some LCDs, pixels respond to voltage (being turned "on" and "off") more slowly than the time it takes for an electron beam to redraw a CRT screen. As a result, fast-moving images can sometimes leave visible trails, called ghosting, or appear blurry on an LCD. ViewSonic ClearMotionTM LCDs have virtually eliminated response-time issues.
3.Viewing angle:
CRT monitors display good brightness and color from a wide viewing angle. Some LCDs, however, look their best when you are directly in front of them, because of the way light passes through liquid crystals in the screen. Keep in mind that LCD technology is rapidly developing, increasing LCD viewing angels, so this CRT advantage doesn't hold true in every case. Check the specs of the monitors you're considering. ViewSonic XtremeView® LCDs have superior viewing angles.
4.Multiple resolutions:
CRT monitors can switch between multiple resolution settings without a significant loss in sharpness. If you need to change your monitor resolution frequently, you may be better off with CRT technology.
5.Lower purchase price:
CRT monitors are generally less expensive at initial purchase than LCDs.
CRT Disadvantages:
1. Sharpness:
The CRT's Gaussian beam profile produces images with softer edges that are not as sharp as an LCD at its native resolution. Imperfect focus and color registration also reduce sharpness. Generally sharper than LCDs at other than native resolutions.
2. Interference:
All color CRTs produce annoying Moiré patterns. Many monitors include Moiré reduction, which normally doesn't eliminate the Moiré interference patterns entirely.
3. Geometric Distortion:
Subject to geometric distortion and screen regulation problems. Also affected by magnetic fields from other equipment including other CRTs.
4. Brightness:
Relatively bright but not as bright as LCDs. Not suitable for very brightly lit environments.
5. Screen Shape:
Some CRTs have a rounded spherical or cylindrical shape screen. Newer CRTs are flat.
6. Emissions:
CRTs give off electric, magnetic and electromagnetic fields. There is considerable controversy as to whether any of these pose a health hazard, particularly magnetic fields. The most authoritative scientific studies conclude that they are not harmful but some people remain unconvinced.
7. Physical:
They are large, heavy, and bulky. They consume a lot of electricity and produce a lot of heat.
Refresh Rate
Improvements in both CRT design and in driver software should by now have killed off the problem of screen flicker, that goes for TFT’s too. If your screen is flickering as you read this, either the hardware needs replacing or it set to too low a refresh rate. Don't put up with flicker - it will give you headaches, make your work harder to do and possibly cause permanent damage to your eyes. For Windows systems, the refresh rate can be found by clicking on the Desktop and selecting 'Properties' and the 'Settings' Tab. The refresh rate is normally found by using the 'Advanced' button and selecting 'Monitor'. You should only change this after consulting the monitor manual and determining the appropriate values for the screen resolution and number of colours you are using - or again you could damage your monitor or lose the screen display.
Tube Designs
Looking at CRT monitors, you have a choice of tube designs, including the older 'slot mask' types and the 'aperture grill' present in Sony 'Trinitron' and the 'Diamondtron' from Mitsubishi. The aperture grill types give a sharper image, but you can see two faint lines across the screen from the supporting wires at roughly one quarter and three quarters of the screen height. Some people find these impossibly intrusive, but I soon grew to ignore them. The better picture quality more than made up for the slight inconvenience.
For most people, a refresh rate of 70Hz or greater will get rid of any flicker, although occasionally some experiment is needed, as certain combinations of values may give problems. You may also want to change the size of your screen fonts. You may also get information about your monitor from any on-screen monitor menus.
Resolution
Size for size, because of their finer dot pitch, CRT displays can use higher resolutions than TFT screens - perhaps 1880x1440 or more for a 21-inch screen. CRTs are also 'multi-synch', giving you a wide choice of resolutions and colour depths to run at. TFT screens are designed to be used at their actual physical resolution and although most can be set to work at other sizes, the picture quality suffers, often dramatically. If you have an 1024x768, screen you need to use it at that size, for the visual side and for the life of the screen.
Bit Depth
Not all TFT screens that claimed to work in 24 bit colour actually did so. Many were made that work with only 6 bits per sub-pixel, giving only 64 possible shades of each colour. The remaining two bits of each 8 were simply ignored. This become even more of a problem if you want to work on black and white images, where 64 grey shades is usually clearly insufficient.
I’ll primarily be focusing TFT displays but there is a few mentions of CRT displays. Basically this is to just explain a few of the main points to buying a monitor. The There are a number of questions asked about TFT/LCD screens, and I will try my best to explain them. The most common are below:
With monitors, when measuring the size of the screen, there are some things to look for. For instance a 17" CRT monitor only has 15.5" visible. With TFT monitors, a 17" monitor has 17" viewable. Therefor a 15" TFT monitor is equivalent to a 17" CRT and a 17" TFT = 19" CRT etc and so on.
TFT displays are usually designed to run at a specific resolution (native resolution). Most 15" TFT displays are designed to run at 1024x768 @ 75Hz. 17” TFT’s run at 1280x1024 @ 75Hz and so on. Although you can use smaller displays like 800x600 but the fonts can look out of proportion and pixelated. Before purchasing it is worth checking that you are happy with this resolution.
Advantages of TFT displays:
1.There is much less glare from a TFT monitor.
2.The monitor is far less bulky. This has a couple of advantages, firstly it gives you more desk space, but secondly because of this you can position the monitor further away from you which most people find more comfortable on the eyes.
3.TFT monitors produce less heat and radiation that CRT monitors.
4.TFT monitors have a very crisp image only comparable to very expensive CRT monitors.
5.The monitor (so long as it is VESA compliant) can be mounted on an arm or on the wall to save even more desk space.
Disadvantages of TFT displays:
1.If you are working with graphics, although the graphics are very clear, due to the limited angle at which you can view the display colours may appear slightly different on non-TFT screens.
2.TFT monitors have a limited angle of view. This is the angle at which you can clearly view the screen. If you are looking directly at the screen while working on your PC this is fine, but if others are trying to read it then they may have difficulty (try looking at a laptop screen from a 45 degree angle).
3.You may experience some blurring on lower end models when there is movement on the screen. This is most prominent in full screen games where you get a motion blur effect but is also noticeable when scrolling through documents or websites.
CRT advantages
1.Accurate color:
CRTs can provide richer color in a fuller spectrum than most LCDs. In general, graphic artists prefer CRT monitors because they show truer colors and greater nuance-particularly useful for preparing files for printing and for using photo applications such as Adobe® Photoshop®.
2.Response time:
CRTs may respond more quickly than some LCDs to videos and fast-action games. For some LCDs, pixels respond to voltage (being turned "on" and "off") more slowly than the time it takes for an electron beam to redraw a CRT screen. As a result, fast-moving images can sometimes leave visible trails, called ghosting, or appear blurry on an LCD. ViewSonic ClearMotionTM LCDs have virtually eliminated response-time issues.
3.Viewing angle:
CRT monitors display good brightness and color from a wide viewing angle. Some LCDs, however, look their best when you are directly in front of them, because of the way light passes through liquid crystals in the screen. Keep in mind that LCD technology is rapidly developing, increasing LCD viewing angels, so this CRT advantage doesn't hold true in every case. Check the specs of the monitors you're considering. ViewSonic XtremeView® LCDs have superior viewing angles.
4.Multiple resolutions:
CRT monitors can switch between multiple resolution settings without a significant loss in sharpness. If you need to change your monitor resolution frequently, you may be better off with CRT technology.
5.Lower purchase price:
CRT monitors are generally less expensive at initial purchase than LCDs.
CRT Disadvantages:
1. Sharpness:
The CRT's Gaussian beam profile produces images with softer edges that are not as sharp as an LCD at its native resolution. Imperfect focus and color registration also reduce sharpness. Generally sharper than LCDs at other than native resolutions.
2. Interference:
All color CRTs produce annoying Moiré patterns. Many monitors include Moiré reduction, which normally doesn't eliminate the Moiré interference patterns entirely.
3. Geometric Distortion:
Subject to geometric distortion and screen regulation problems. Also affected by magnetic fields from other equipment including other CRTs.
4. Brightness:
Relatively bright but not as bright as LCDs. Not suitable for very brightly lit environments.
5. Screen Shape:
Some CRTs have a rounded spherical or cylindrical shape screen. Newer CRTs are flat.
6. Emissions:
CRTs give off electric, magnetic and electromagnetic fields. There is considerable controversy as to whether any of these pose a health hazard, particularly magnetic fields. The most authoritative scientific studies conclude that they are not harmful but some people remain unconvinced.
7. Physical:
They are large, heavy, and bulky. They consume a lot of electricity and produce a lot of heat.
Refresh Rate
Improvements in both CRT design and in driver software should by now have killed off the problem of screen flicker, that goes for TFT’s too. If your screen is flickering as you read this, either the hardware needs replacing or it set to too low a refresh rate. Don't put up with flicker - it will give you headaches, make your work harder to do and possibly cause permanent damage to your eyes. For Windows systems, the refresh rate can be found by clicking on the Desktop and selecting 'Properties' and the 'Settings' Tab. The refresh rate is normally found by using the 'Advanced' button and selecting 'Monitor'. You should only change this after consulting the monitor manual and determining the appropriate values for the screen resolution and number of colours you are using - or again you could damage your monitor or lose the screen display.
Tube Designs
Looking at CRT monitors, you have a choice of tube designs, including the older 'slot mask' types and the 'aperture grill' present in Sony 'Trinitron' and the 'Diamondtron' from Mitsubishi. The aperture grill types give a sharper image, but you can see two faint lines across the screen from the supporting wires at roughly one quarter and three quarters of the screen height. Some people find these impossibly intrusive, but I soon grew to ignore them. The better picture quality more than made up for the slight inconvenience.
For most people, a refresh rate of 70Hz or greater will get rid of any flicker, although occasionally some experiment is needed, as certain combinations of values may give problems. You may also want to change the size of your screen fonts. You may also get information about your monitor from any on-screen monitor menus.
Resolution
Size for size, because of their finer dot pitch, CRT displays can use higher resolutions than TFT screens - perhaps 1880x1440 or more for a 21-inch screen. CRTs are also 'multi-synch', giving you a wide choice of resolutions and colour depths to run at. TFT screens are designed to be used at their actual physical resolution and although most can be set to work at other sizes, the picture quality suffers, often dramatically. If you have an 1024x768, screen you need to use it at that size, for the visual side and for the life of the screen.
Bit Depth
Not all TFT screens that claimed to work in 24 bit colour actually did so. Many were made that work with only 6 bits per sub-pixel, giving only 64 possible shades of each colour. The remaining two bits of each 8 were simply ignored. This become even more of a problem if you want to work on black and white images, where 64 grey shades is usually clearly insufficient.