- Joined
- Dec 13, 2003
- Location
- Saint Louis, MO USA
Hey fellow Overclockers!
I write a column for my company newsletter every quarter. The column is called "MoreGooder Methods". Probably not surprising to you folks. Anyway, this is an article I submitted today that you might find useful if you're looking into high definition televisions. ENJOY!
MoreGooder Methods
What will you do with your rabbit ears?
Introduction
As you might know, our federal government has mandated that all broadcasts switch over to digital. Eventually, that is. Even though it is unnecessary, many consumers are shopping for digital televisions to prepare for that shiny day (but, in reality, converter boxes will be readily available). But, did you know that digital television will not automatically mean high definition? And, did you know that new programs are not necessarily going to be widescreen? If you subscribe to a digital cable or satellite service you already know that. Nevertheless, high definition broadcasts are becoming common, and as a consumer you are being directed down the high definition TV aisle when you walk into an electronics store. If you’re interested in a high definition display then this article is for you.
If you haven't taken the plunge yet on a new high definition TV then you might consider yourself lucky. Technology improvements have yielded fantastic advances since the first high definition displays hit the scene about 4 years ago. This article will delve into some of the finer points for selecting a high definition television so you can make the best choice. You might just learn some things about the technologies available and their specific characteristics that will influence your decision.
First, an issue on everyone's mind today: Widescreen
You know, there's a good reason that when you go to a movie you're sitting in front of an enormously wide screen. It's all about the panorama. Widescreen televisions use a length to width ratio of 16:10 generally. By comparison, the traditional television 4:3 ratio restricts what enters your eyes and limits a director's playground for all of that visual stimulus. Traditional TV studio sets are small by comparison to those used for movies, and as a result, camera angle changes are numerous. It's actually tiring to view a long movie in 4:3 format due to the frequent and sudden camera angle changes. When you view a movie on a 4:3 display it will often be “edited for television”, which really means you will see a slice of the original scene that has been selected by the studio. Hopefully the only visual information trimmed off on either side is unimportant for the storyline. What is lost is a bit of the atmosphere of the scene as envisioned by the director. When you view a movie on a 4:3 tube it is either "pan and scan" or "letterbox". The only time you can chose between the two is for DVD viewing. Over the past year I have noticed that movies broadcast in the letterbox format have become common. I attribute that to both customer demand and pressure from the display industry.
One common misconception, however, is that high definition broadcasts are always going to be widescreen. That's not the case now and probably won't be the case for some time to come. The reason is that there are 100's of millions of TV's out there that are not going to be thrown in the dump because of their screen size ratio. Additionally, it takes more bandwidth to transmit all of these extra 1's and 0's that fill out a widescreen display. Is it necessary for the evening news? Maybe. Is it necessary for viewing an I Love Lucy rerun? Of course not. When the switch over to digital broadcasting finally happens, your old rabbit ears will be the only thing that becomes obsolete. There will be an abundance of converter boxes that will pick up the new signal and convert it to an old one that you will connect to your traditional TV. And, if you're a cable subscriber you won't need to do anything at all (except for putting up with the phone calls begging you to switch to a new service). 4:3 ratio broadcast is here to stay because it has been the standard since the beginning.
So, how do you view 4:3 on a 16:10 widescreen? That depends on the screen and the manufacturer. Most manufactures offer a way to stretch the 4:3 image to fill the screen. Frankly, I think that this distorts the image far too much. Many people always watch with the stretch mode enabled and claim to have gotten used to the faulty image. The alternative to a stretch mode is to have wide bars on the sides with the original image displayed in the middle.
Competing technologies
There are currently four technologies competing for your videophile dollars: Direct view CRT, Plasma, LCD and Projection. However, each type of display has strengths and weaknesses. Certain negative characteristics of one technology might outweigh a benefit. Much of the decision process is, in the end, a choice governed by your viewing habits and ability to compromise. If you thought compromise wasn't part of this decision please read on.
Direct View Cathode Ray Tube (CRT)
This type of television is the same type you grew up with, except now they are capable of displaying high definition images. You can choose between 16:10 widescreen and traditional 4:3 ratio tubes. High def tubes were initially the most cost effective way to dive into high definition. The basic technology behind the CRT has largely unchanged, and that means that the same pros and cons you are already familiar with prevail. The most notable deficit to this type is the massive size. Big tubes can't compete with the slim contemporary look of an LCD or Plasma display. However, there are some very appealing characteristics to what appears to be an outdated technology. Tube displays use highly refined phosphors that produce brilliant colors with strong contrast. They can also display many more colors than any of the other technologies, especially blacks, near blacks and dark colors. You're used to the look of a CRT already. But, have you seen a high definition CRT? Or do you simply walk right pass them on the way to flat screens. If space is not a constraint and you don't care so much about keeping up with the Jones's, then you should stop in the CRT aisle and take a look. Once you've browsed the Plasma and LCD isle, go back to the CRT isle for yet another look. Hardcore CRT enthusiasts won't even visit the other aisles, but you will find that their favorite aisle is never crowded.
CRT strong points:
· Very high image contrast.
· Exceptional flesh tones (believe it or not, some displays show these colors poorly or with splotches).
· Discernable grays for dark scenes.
· Can display any resolution at or below the maximum resolution without resorting to blurry pixel interpolation
· Extremely fast display image changes (<1ms). No image blurring (a.k.a. "ghosting").
· Unlikely to be subject to image burn-in during normal use.
CRT weaknesses:
· Bulky
· Power hungry
· Not available in extremely large sizes.
· Wall mounting impractical
Plasma
Plasma televisions have been available for mass consumption for a relatively short time, although the technology has been in various stages of development since the 60's. Essentially, plasma televisions are made up of clusters of microscopic fluorescent tubes with either a red, green or blue phosphor coating. Each cluster of the three colors forms a "pixel", and these pixels combine together to create the image. Occasionally, one of the pixels can be "dead" or “stuck” on a specific color. Manufacturers often set a dead pixel product return policy that is intended to protect you from a distracting number of faulty pixels. Generally, a few pixels in the dead or stuck position are quickly forgotten or go unnoticed because of their minuscule size.
Pricing for plasmas has been dropping dramatically this year, so much so that many people who considered themselves in a price range worthy only of a rear projection display are now able to purchase a low or mid range Plasma. Some even predict rear projection and CRT sets to suffer a further decline in popularity as the other technologies, and especially Plasma, drop in price.
There is a specific downside to plasma displays that warrants a dedicated paragraph: Image burn-in. This occurs when the same image is displayed on the screen for days on end. The History Channel's logo is notorious for ruining plasma displays, as well as CNN and CNN Headline News. As a pixel is used, the phosphor degrades, just as is the case for a CRT display. Unfortunately, that image appears "burned in" to the display because the phosphors of the affected pixels have been prematurely degraded. There is good news, though. Panasonic and Pioneer have developed new phosphor coatings that have greatly increased the duration required for image burn-in and have increased the longevity of the display overall. Hopefully the other manufactures will play catch-up because those new sets sell at a premium. Other techniques to reduce image burn-in are mostly ineffective. Image "wobble" was touted as a solution, however what actually ends up happening is that the rotten History channel "H" merely ends up being a blurry "H".
The first 100 hours of viewing is critical for a Plasma set because the phosphors are brand new and highly susceptible to burn-in. Be sure to view only widescreen media during the break-in period.
Image burn-in is not the same as image retention. You may have noticed that after you turn off a CRT or Plasma the screen isn’t completely black, and might even show hints of what was just recently displayed. Over the course of a few minutes that image will fade away. This is a characteristic of the phosphor coating and is harmless. Burn-in is permanent damage due to over-use of specific pixels.
If you view 4:3 content in a non-stretched mode for days on end you will degrade the phosphors in the middle faster than the outside bands. Most manufactures allow you to set the black areas on the side to gray instead. This will largely solve the problem since all three colors are used to produce the gray image. Secondly, and most importantly, turn down the contrast setting as this will degrade the phosphors quickly. Factory settings for all televisions are far too bright. They do this because when the set is on the display shelf it must stick out from the rest. You don't notice it being too bright in the store because the store is well lit and there are other sets in close proximity
Plasma strengths
· Thin.
· Exceptionally rich colors
· "180 degree" viewing angle.
· Shares the same exceptional pixel response as CRT because of phosphor coating.
· Heavy by comparison to an LCD.
· Wall mountable.
Plasma downsides
· Not energy efficient
· Can produce a great deal of heat, and might use a noisy cooling fan to compensate.
· Fixed native pixel resolution. Lower resolutions must be interpolated, with varying degrees of success.
· Display sizes are generally too large for use as computer monitors. (The smallest I've seen is 37" diagonal)
· Can suffer from image "burn-in", especially for signage applications.
· Phosphor "Half life" that can vary greatly. Look for one that has >50,000 hours.
· Budget and mid grade sets have poor black levels by comparison to CRT.
· Critical 100 hour break in period
Liquid Crystal Displays (LCD)
You're probably reading this article from an LCD display. LCD display produces its image by means of red green and blue pixels as well. However, the colors are produced in a substantially different way. LCD's are classified as "transmitive" displays because they allow a backlight to pass through a filter, as opposed to an emissive display such as a CRT or Plasma. It is these tiny filters that combine together to form a pixel. As the image change is called by the processor, the liquid crystal molecules twist in response to the electric charge and thus allow light to pass through. This twisting takes considerable time to occur by comparison to lighting up a phosphor coating. Have you ever noticed blurring or smearing when you move a window around on your LCD monitor? Some really horrible early LCD's will even blur your mouse cursor as it moves, so much so that you might think you had accidentally turned on the "mouse trail" feature. That's called "ghosting", and it is a real problem for LCD televisions and computer monitors. LCD's work great for viewing text, web pages or fixed images, but they have a real problem when it comes to displaying fast moving images. This is because it takes time to change the pixel color. Oddly, it takes more time for an LCD pixel to settle on a midtone or gray than it does to transition from black to white. This is because the speed at which the twist occurs is relative to the amount of voltage applied to the pixel control lines. To speed up the transition, manufacturers have recently devised a way to overdrive the pixels. For example, if color 150 (gray) is requested, the circuitry will briefly request color 250 (white) then back off quickly to 150. The result is a drop on pixel response time as much as 75%. This technique comes at an image quality cost however. Due to the overshoot a discernable sparkling effect occurs, especially on large color areas of the image such as the sky or a close-up of a person's face. There simply isn't enough dramatic change in the requested colors for those areas, and hence you will be able to discern the overshoot. The further you are away from the display, the less you notice the sparkle. Likewise, different models from the same manufacturer will use different LCD screen types, and each one has a different method of dealing with pixel response.
LCD’s can also suffer from dead or stuck pixels, and a dead pixel return policy often applies. Check the specs before buying. If possible, view your set before taking it home.
Unlike CRT's and Plasma displays, it is impossible to burn in an image on an LCD. There are no phosphors to degrade. Generally, an LCD will last as long as the backlight source and that means many years of viewing. Some manufactures have replacement kits for LCD’s which can return the set to brand-new condition.
LCD strengths:
· Thin.
· Rich colors
· High energy efficiency.
· Long lifespan, especially for sets that allow backlight replacement.
· Available in small sizes suitable for a computer monitor.
· Immune to image "burn-in".
· Wall mountable.
LCD downsides:
· Have a fixed native pixel resolution. Lower resolutions must be interpolated.
· Viewing angle varies from model to model. Picture quality varies dramatically as the viewer moves relative to the screen, although not nearly as badly as for a projection TV.
· Sale price relative to picture size is rather steep.
· Budget and mid grade sets have poor black levels by comparison to CRT.
· Currently the most expensive high definition technology
· Cannot produce high contrast images, and have problems displaying subtle shades of gray.
· Blurring and ghosting of fast moving images inherent in the technology.
· Twinkle effect due to pixel overdrive.
· Backlight decreases in brightness over time.
Rear Projection
Projection televisions are another option, and are now quite affordable. Be aware, however, that the same characteristics applicable for the source of the projected image still apply to a projection set. If the source of the image is a tiny LCD screen, then the same characteristics of LCD displays apply. The only unique display technology available exclusively to the projection class is DLP (Digital Light Processing). This technology is used exclusively for projection systems because it's basically a highly sophisticated set of microscopic mirrors on a silicone substrate that reflect colored light. These were first developed by Texas Instruments in 2004 as a direct offspring of MEMS chip technology development. (MEMS is a huge topic that is not in the scope of this article). As with the other technologies, there are tradeoffs to consider. Most DLP based projectors use a color wheel that spins at a fixed speed. As the correct color passes by the chip, the mirrors switch into position if that color must be displayed at the screen. Some people can see the color banding that occurs and find this to be unacceptable. Another downside is that the mirrors have edges which cause a rainbow effect. Some strides have been taken to eliminate this effect, so be sure to check the specs and reviews.
Projection sets also have a limited viewing range, with luminosity varying considerably as the viewer changes position.
Other high definition projection sets use small cathode ray tubes for red green and blue that combined together through optics to display the image on the screen. This is very mature technique that has merely been updated to high definition. They suffer from color convergence issues as the previous generations and require calibration to get a decent picture, especially once moved into your home.
Projection Pros:
· Relatively inexpensive
· Wide selection in screen sizes available.
· Mature technology
· Has the same advantages as the underlying technology used for the image source.
· DLP technology available as an alternative image source.
Projection Cons:
· Very poor image viewing angle.
· Color convergence constantly threatens picture quality and required tuning.
· Bulky
· Suffers the same disadvantages as the underlying technology producing the projected image.
· Brightly lit rooms are not advised for projection sets.
What to do when you visit the electronics retailer:
First, let's back up a second. Notice the word "retailer" above. My advice to you is to never buy a new television from an online e-tailer unless you first see the same exact model in person, and you are OK with paying the exorbitant shipping charges. If there's something wrong with your new set or you are not satisfied with the picture quality, shipping it back to an e-tailer can be a huge hassle and very expensive. Use the e-tailer websites for a price comparison and perhaps for anecdotal user reviews, but draw the line in your wallet right there. Keep the original packaging for at least 30 days no matter how you execute your purchase.
The problem with most of the large retailers in my opinion is that they tend to arrange their display products according to their underlying technologies. Perhaps it's for convenience or perhaps it's due to agreements with the manufacturers. In an ideal store we'd see similarly sized displays of each technology side by side showing the same image, and properly calibrated for tone and luminosity. I don't see that happening because it's too inconvenient for the staff to keep the sets properly tuned, especially when they become "old" models in 6 months anyway.
Be sure to check out all of the technologies for the size screen that interests you. And do this cycle several times, and on different days. These sets are generally quite expensive. I don't recommend impulse buys for a TV no matter how much of a discount you see on the price tag. It might be on sale for a good reason (overstock, discontinued) or a bad reason (poor sells, many returns). The key here is to identify the display you want then shop around. Some stores offer price guarantees and price matching, but they can stick it to you with high delivery charges. Get the bottom line price. Never purchase a floor model Plasma or CRT, because you are purchasing a television that has been in heavy use at maximum contrast since the day it was taken out of the box.
Well, that basically summarizes the information I have collected for high definition displays. For the record, I purchased a high definition Sony 36" CRT 2 years ago. My decision at the time was largely influenced by the price relative to Plasma. LCD TV's hadn't even hit the market yet, and my old CRT had recently died. My Sony is a fantastic TV, but it's not widescreen. Widescreen viewing on this set is not all that enjoyable because the image is too small. It is because of this that I have been researching widescreens. As prices continue to fall I will be ever more tempted to buy. Right now, my eyes are on the new Panasonic Plasma sets that utilize the new phosphors. They produce incredibly rich color, deep blacks, and reportedly do not have issues with image burn-in. If you're eyeing the LCD technology, there is recent news regarding the pixel response rate issue. A few manufacturers of LCD computer monitors are developing new techniques to improve pixel response. One is to drive the entire image at double the normal rate. The other is to introduce an "image wiping" blank screen to trick the eyes into thinking the image is moving smoothly, similar to watching a movie on the big screen. I look for LCD's to gain a bigger foothold, but I see Plasmas being the most popular, while purist will still favor the CRT.
Most importantly, if you're waiting for something better to come along before you buy, then you'll be waiting forever. High definition sets have come of age. The market for high definition televisions is huge, and competition for your dollars is driving constant improvement, but the improvements are mostly small tweaks. Spend ample time to make your choice of what's available, make your purchase proudly, and then enjoy watching!
I write a column for my company newsletter every quarter. The column is called "MoreGooder Methods". Probably not surprising to you folks. Anyway, this is an article I submitted today that you might find useful if you're looking into high definition televisions. ENJOY!
MoreGooder Methods
What will you do with your rabbit ears?
Introduction
As you might know, our federal government has mandated that all broadcasts switch over to digital. Eventually, that is. Even though it is unnecessary, many consumers are shopping for digital televisions to prepare for that shiny day (but, in reality, converter boxes will be readily available). But, did you know that digital television will not automatically mean high definition? And, did you know that new programs are not necessarily going to be widescreen? If you subscribe to a digital cable or satellite service you already know that. Nevertheless, high definition broadcasts are becoming common, and as a consumer you are being directed down the high definition TV aisle when you walk into an electronics store. If you’re interested in a high definition display then this article is for you.
If you haven't taken the plunge yet on a new high definition TV then you might consider yourself lucky. Technology improvements have yielded fantastic advances since the first high definition displays hit the scene about 4 years ago. This article will delve into some of the finer points for selecting a high definition television so you can make the best choice. You might just learn some things about the technologies available and their specific characteristics that will influence your decision.
First, an issue on everyone's mind today: Widescreen
You know, there's a good reason that when you go to a movie you're sitting in front of an enormously wide screen. It's all about the panorama. Widescreen televisions use a length to width ratio of 16:10 generally. By comparison, the traditional television 4:3 ratio restricts what enters your eyes and limits a director's playground for all of that visual stimulus. Traditional TV studio sets are small by comparison to those used for movies, and as a result, camera angle changes are numerous. It's actually tiring to view a long movie in 4:3 format due to the frequent and sudden camera angle changes. When you view a movie on a 4:3 display it will often be “edited for television”, which really means you will see a slice of the original scene that has been selected by the studio. Hopefully the only visual information trimmed off on either side is unimportant for the storyline. What is lost is a bit of the atmosphere of the scene as envisioned by the director. When you view a movie on a 4:3 tube it is either "pan and scan" or "letterbox". The only time you can chose between the two is for DVD viewing. Over the past year I have noticed that movies broadcast in the letterbox format have become common. I attribute that to both customer demand and pressure from the display industry.
One common misconception, however, is that high definition broadcasts are always going to be widescreen. That's not the case now and probably won't be the case for some time to come. The reason is that there are 100's of millions of TV's out there that are not going to be thrown in the dump because of their screen size ratio. Additionally, it takes more bandwidth to transmit all of these extra 1's and 0's that fill out a widescreen display. Is it necessary for the evening news? Maybe. Is it necessary for viewing an I Love Lucy rerun? Of course not. When the switch over to digital broadcasting finally happens, your old rabbit ears will be the only thing that becomes obsolete. There will be an abundance of converter boxes that will pick up the new signal and convert it to an old one that you will connect to your traditional TV. And, if you're a cable subscriber you won't need to do anything at all (except for putting up with the phone calls begging you to switch to a new service). 4:3 ratio broadcast is here to stay because it has been the standard since the beginning.
So, how do you view 4:3 on a 16:10 widescreen? That depends on the screen and the manufacturer. Most manufactures offer a way to stretch the 4:3 image to fill the screen. Frankly, I think that this distorts the image far too much. Many people always watch with the stretch mode enabled and claim to have gotten used to the faulty image. The alternative to a stretch mode is to have wide bars on the sides with the original image displayed in the middle.
Competing technologies
There are currently four technologies competing for your videophile dollars: Direct view CRT, Plasma, LCD and Projection. However, each type of display has strengths and weaknesses. Certain negative characteristics of one technology might outweigh a benefit. Much of the decision process is, in the end, a choice governed by your viewing habits and ability to compromise. If you thought compromise wasn't part of this decision please read on.
Direct View Cathode Ray Tube (CRT)
This type of television is the same type you grew up with, except now they are capable of displaying high definition images. You can choose between 16:10 widescreen and traditional 4:3 ratio tubes. High def tubes were initially the most cost effective way to dive into high definition. The basic technology behind the CRT has largely unchanged, and that means that the same pros and cons you are already familiar with prevail. The most notable deficit to this type is the massive size. Big tubes can't compete with the slim contemporary look of an LCD or Plasma display. However, there are some very appealing characteristics to what appears to be an outdated technology. Tube displays use highly refined phosphors that produce brilliant colors with strong contrast. They can also display many more colors than any of the other technologies, especially blacks, near blacks and dark colors. You're used to the look of a CRT already. But, have you seen a high definition CRT? Or do you simply walk right pass them on the way to flat screens. If space is not a constraint and you don't care so much about keeping up with the Jones's, then you should stop in the CRT aisle and take a look. Once you've browsed the Plasma and LCD isle, go back to the CRT isle for yet another look. Hardcore CRT enthusiasts won't even visit the other aisles, but you will find that their favorite aisle is never crowded.
CRT strong points:
· Very high image contrast.
· Exceptional flesh tones (believe it or not, some displays show these colors poorly or with splotches).
· Discernable grays for dark scenes.
· Can display any resolution at or below the maximum resolution without resorting to blurry pixel interpolation
· Extremely fast display image changes (<1ms). No image blurring (a.k.a. "ghosting").
· Unlikely to be subject to image burn-in during normal use.
CRT weaknesses:
· Bulky
· Power hungry
· Not available in extremely large sizes.
· Wall mounting impractical
Plasma
Plasma televisions have been available for mass consumption for a relatively short time, although the technology has been in various stages of development since the 60's. Essentially, plasma televisions are made up of clusters of microscopic fluorescent tubes with either a red, green or blue phosphor coating. Each cluster of the three colors forms a "pixel", and these pixels combine together to create the image. Occasionally, one of the pixels can be "dead" or “stuck” on a specific color. Manufacturers often set a dead pixel product return policy that is intended to protect you from a distracting number of faulty pixels. Generally, a few pixels in the dead or stuck position are quickly forgotten or go unnoticed because of their minuscule size.
Pricing for plasmas has been dropping dramatically this year, so much so that many people who considered themselves in a price range worthy only of a rear projection display are now able to purchase a low or mid range Plasma. Some even predict rear projection and CRT sets to suffer a further decline in popularity as the other technologies, and especially Plasma, drop in price.
There is a specific downside to plasma displays that warrants a dedicated paragraph: Image burn-in. This occurs when the same image is displayed on the screen for days on end. The History Channel's logo is notorious for ruining plasma displays, as well as CNN and CNN Headline News. As a pixel is used, the phosphor degrades, just as is the case for a CRT display. Unfortunately, that image appears "burned in" to the display because the phosphors of the affected pixels have been prematurely degraded. There is good news, though. Panasonic and Pioneer have developed new phosphor coatings that have greatly increased the duration required for image burn-in and have increased the longevity of the display overall. Hopefully the other manufactures will play catch-up because those new sets sell at a premium. Other techniques to reduce image burn-in are mostly ineffective. Image "wobble" was touted as a solution, however what actually ends up happening is that the rotten History channel "H" merely ends up being a blurry "H".
The first 100 hours of viewing is critical for a Plasma set because the phosphors are brand new and highly susceptible to burn-in. Be sure to view only widescreen media during the break-in period.
Image burn-in is not the same as image retention. You may have noticed that after you turn off a CRT or Plasma the screen isn’t completely black, and might even show hints of what was just recently displayed. Over the course of a few minutes that image will fade away. This is a characteristic of the phosphor coating and is harmless. Burn-in is permanent damage due to over-use of specific pixels.
If you view 4:3 content in a non-stretched mode for days on end you will degrade the phosphors in the middle faster than the outside bands. Most manufactures allow you to set the black areas on the side to gray instead. This will largely solve the problem since all three colors are used to produce the gray image. Secondly, and most importantly, turn down the contrast setting as this will degrade the phosphors quickly. Factory settings for all televisions are far too bright. They do this because when the set is on the display shelf it must stick out from the rest. You don't notice it being too bright in the store because the store is well lit and there are other sets in close proximity
Plasma strengths
· Thin.
· Exceptionally rich colors
· "180 degree" viewing angle.
· Shares the same exceptional pixel response as CRT because of phosphor coating.
· Heavy by comparison to an LCD.
· Wall mountable.
Plasma downsides
· Not energy efficient
· Can produce a great deal of heat, and might use a noisy cooling fan to compensate.
· Fixed native pixel resolution. Lower resolutions must be interpolated, with varying degrees of success.
· Display sizes are generally too large for use as computer monitors. (The smallest I've seen is 37" diagonal)
· Can suffer from image "burn-in", especially for signage applications.
· Phosphor "Half life" that can vary greatly. Look for one that has >50,000 hours.
· Budget and mid grade sets have poor black levels by comparison to CRT.
· Critical 100 hour break in period
Liquid Crystal Displays (LCD)
You're probably reading this article from an LCD display. LCD display produces its image by means of red green and blue pixels as well. However, the colors are produced in a substantially different way. LCD's are classified as "transmitive" displays because they allow a backlight to pass through a filter, as opposed to an emissive display such as a CRT or Plasma. It is these tiny filters that combine together to form a pixel. As the image change is called by the processor, the liquid crystal molecules twist in response to the electric charge and thus allow light to pass through. This twisting takes considerable time to occur by comparison to lighting up a phosphor coating. Have you ever noticed blurring or smearing when you move a window around on your LCD monitor? Some really horrible early LCD's will even blur your mouse cursor as it moves, so much so that you might think you had accidentally turned on the "mouse trail" feature. That's called "ghosting", and it is a real problem for LCD televisions and computer monitors. LCD's work great for viewing text, web pages or fixed images, but they have a real problem when it comes to displaying fast moving images. This is because it takes time to change the pixel color. Oddly, it takes more time for an LCD pixel to settle on a midtone or gray than it does to transition from black to white. This is because the speed at which the twist occurs is relative to the amount of voltage applied to the pixel control lines. To speed up the transition, manufacturers have recently devised a way to overdrive the pixels. For example, if color 150 (gray) is requested, the circuitry will briefly request color 250 (white) then back off quickly to 150. The result is a drop on pixel response time as much as 75%. This technique comes at an image quality cost however. Due to the overshoot a discernable sparkling effect occurs, especially on large color areas of the image such as the sky or a close-up of a person's face. There simply isn't enough dramatic change in the requested colors for those areas, and hence you will be able to discern the overshoot. The further you are away from the display, the less you notice the sparkle. Likewise, different models from the same manufacturer will use different LCD screen types, and each one has a different method of dealing with pixel response.
LCD’s can also suffer from dead or stuck pixels, and a dead pixel return policy often applies. Check the specs before buying. If possible, view your set before taking it home.
Unlike CRT's and Plasma displays, it is impossible to burn in an image on an LCD. There are no phosphors to degrade. Generally, an LCD will last as long as the backlight source and that means many years of viewing. Some manufactures have replacement kits for LCD’s which can return the set to brand-new condition.
LCD strengths:
· Thin.
· Rich colors
· High energy efficiency.
· Long lifespan, especially for sets that allow backlight replacement.
· Available in small sizes suitable for a computer monitor.
· Immune to image "burn-in".
· Wall mountable.
LCD downsides:
· Have a fixed native pixel resolution. Lower resolutions must be interpolated.
· Viewing angle varies from model to model. Picture quality varies dramatically as the viewer moves relative to the screen, although not nearly as badly as for a projection TV.
· Sale price relative to picture size is rather steep.
· Budget and mid grade sets have poor black levels by comparison to CRT.
· Currently the most expensive high definition technology
· Cannot produce high contrast images, and have problems displaying subtle shades of gray.
· Blurring and ghosting of fast moving images inherent in the technology.
· Twinkle effect due to pixel overdrive.
· Backlight decreases in brightness over time.
Rear Projection
Projection televisions are another option, and are now quite affordable. Be aware, however, that the same characteristics applicable for the source of the projected image still apply to a projection set. If the source of the image is a tiny LCD screen, then the same characteristics of LCD displays apply. The only unique display technology available exclusively to the projection class is DLP (Digital Light Processing). This technology is used exclusively for projection systems because it's basically a highly sophisticated set of microscopic mirrors on a silicone substrate that reflect colored light. These were first developed by Texas Instruments in 2004 as a direct offspring of MEMS chip technology development. (MEMS is a huge topic that is not in the scope of this article). As with the other technologies, there are tradeoffs to consider. Most DLP based projectors use a color wheel that spins at a fixed speed. As the correct color passes by the chip, the mirrors switch into position if that color must be displayed at the screen. Some people can see the color banding that occurs and find this to be unacceptable. Another downside is that the mirrors have edges which cause a rainbow effect. Some strides have been taken to eliminate this effect, so be sure to check the specs and reviews.
Projection sets also have a limited viewing range, with luminosity varying considerably as the viewer changes position.
Other high definition projection sets use small cathode ray tubes for red green and blue that combined together through optics to display the image on the screen. This is very mature technique that has merely been updated to high definition. They suffer from color convergence issues as the previous generations and require calibration to get a decent picture, especially once moved into your home.
Projection Pros:
· Relatively inexpensive
· Wide selection in screen sizes available.
· Mature technology
· Has the same advantages as the underlying technology used for the image source.
· DLP technology available as an alternative image source.
Projection Cons:
· Very poor image viewing angle.
· Color convergence constantly threatens picture quality and required tuning.
· Bulky
· Suffers the same disadvantages as the underlying technology producing the projected image.
· Brightly lit rooms are not advised for projection sets.
What to do when you visit the electronics retailer:
First, let's back up a second. Notice the word "retailer" above. My advice to you is to never buy a new television from an online e-tailer unless you first see the same exact model in person, and you are OK with paying the exorbitant shipping charges. If there's something wrong with your new set or you are not satisfied with the picture quality, shipping it back to an e-tailer can be a huge hassle and very expensive. Use the e-tailer websites for a price comparison and perhaps for anecdotal user reviews, but draw the line in your wallet right there. Keep the original packaging for at least 30 days no matter how you execute your purchase.
The problem with most of the large retailers in my opinion is that they tend to arrange their display products according to their underlying technologies. Perhaps it's for convenience or perhaps it's due to agreements with the manufacturers. In an ideal store we'd see similarly sized displays of each technology side by side showing the same image, and properly calibrated for tone and luminosity. I don't see that happening because it's too inconvenient for the staff to keep the sets properly tuned, especially when they become "old" models in 6 months anyway.
Be sure to check out all of the technologies for the size screen that interests you. And do this cycle several times, and on different days. These sets are generally quite expensive. I don't recommend impulse buys for a TV no matter how much of a discount you see on the price tag. It might be on sale for a good reason (overstock, discontinued) or a bad reason (poor sells, many returns). The key here is to identify the display you want then shop around. Some stores offer price guarantees and price matching, but they can stick it to you with high delivery charges. Get the bottom line price. Never purchase a floor model Plasma or CRT, because you are purchasing a television that has been in heavy use at maximum contrast since the day it was taken out of the box.
Well, that basically summarizes the information I have collected for high definition displays. For the record, I purchased a high definition Sony 36" CRT 2 years ago. My decision at the time was largely influenced by the price relative to Plasma. LCD TV's hadn't even hit the market yet, and my old CRT had recently died. My Sony is a fantastic TV, but it's not widescreen. Widescreen viewing on this set is not all that enjoyable because the image is too small. It is because of this that I have been researching widescreens. As prices continue to fall I will be ever more tempted to buy. Right now, my eyes are on the new Panasonic Plasma sets that utilize the new phosphors. They produce incredibly rich color, deep blacks, and reportedly do not have issues with image burn-in. If you're eyeing the LCD technology, there is recent news regarding the pixel response rate issue. A few manufacturers of LCD computer monitors are developing new techniques to improve pixel response. One is to drive the entire image at double the normal rate. The other is to introduce an "image wiping" blank screen to trick the eyes into thinking the image is moving smoothly, similar to watching a movie on the big screen. I look for LCD's to gain a bigger foothold, but I see Plasmas being the most popular, while purist will still favor the CRT.
Most importantly, if you're waiting for something better to come along before you buy, then you'll be waiting forever. High definition sets have come of age. The market for high definition televisions is huge, and competition for your dollars is driving constant improvement, but the improvements are mostly small tweaks. Spend ample time to make your choice of what's available, make your purchase proudly, and then enjoy watching!
