HDTV Science

The History of HDTV’s

 

What’s an LCD HDTV?

 

What’s a Plasma TV?

 

Viewing Distance

 

HDTV Definitions

 

Resolution FAQ’s

 

Resolution HOW?

 

1080p

 

720p

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What’s a Plasma Television?

Plasma Television BASICS

 

How does a plasma HDTV work? Let me start of by saying that physics play a huge part in this marvel of gas made up of free flowing ions and electrons. Plasma TV’s use thousands of sealed, low level pressure glass chambers. These chambers are filled with a mixture of gas, “neon gas” and “xenon gas”. Behind these chambers are 3 different colored phosphors, RED, GREEN and BLUE for each chamber. When energized these chambers of Plasma (Gas) emit invisible UV light. The UV light then excites the RED, GREEN, and BLUE phosphors on the rear of the glass display enabling them to produce visible light.

How long will a plasma Television last?

 

Okay, we have all heard the rumor that plasma TV’s don’t last long and we should not waste our money on one. This is not the case... Depending on the brand of plasma television it can last you as long as an LCD television. I would be dishonest if I told you that Plasma life span debates has not been a hot topic over the years. What I can tell you is that during the first few years of the plasma TV they were lacking the technology to propel them ahead into today. Now that is just not the case. Improvements in technology have rapidly busted the plasma HDTV into living rooms all over the world. This is mainly due to the life span improvements made by most all plasma manufactures. First generation plasma TV’s were rated around 30,000 hours. Now you can walk into almost any electronics store and buy a plasma HDTV rated for at least 50,000 to 60,000 hours and getting longer as technology advances.

What will you be using your plasma HDTV for?

 

What are you going to be doing with your plasma HDTV? Movies, video games, watching basic TV or an alternate computer monitor?

Whatever your needs are will determine what features are more important  than others. If you are going to be watching mostly High Definition movies & gaming then screen resolution, refresh rate, response time and contrast ratio should be some of your considerations. If your going to be using your plasma HDTV for basic TV viewing then you might be more concerned with screen size and price. If your going to be using your plasma HDTV for an alternate computer monitor you might be more concerned with it’s input options, screen resolution and aspect ratio. But whatever your heart desires there is an HDTV solution out there to fit you need and budget. We will help you get there! Remember plasma has been ahead of the curve when it comes to contrast, refresh rates, and viewing angle!

Specifications you need to know!

Okay, Lets get our first glimpse at what Specifications are going to be a deciding factor in buying your new HDTV.

 

Aspect Ratio

Most Plasma HDTV’s come in two different aspect ratios 4:3 and 16:9. Depending on what you will be using your HDTV for, should determine what aspect ratio you decide to go with. 4:3 is your standard viewing size “regular TV size” 16:9 is your wide screen size “movie screen dimensions”. You can make your decision based on a few factors. If you have an entertainment center that is designed for a TV with a 4:3 aspect ratio you will have to sacrifice screen size if you want to put a 16:9 aspect ratio HDTV in that same entertainment center. If you are planing to upgrade your entertainment center when you upgrade your HDTV then you should decide on what size TV you want first and then find a entertainment center or HDTV stand that is tailored fit to your new HDTV. Keep in mind that most HDTV’s on the market are 16:9 aspect ratio. So finding exactly what you want in a 16:9 aspect ratio is more likely and 4:3’s are being phased out by natural selection in the plasma world. If you decide to stay with your current entertainment center then you should measure it and shop your new HDTV according to you size requirements.

Native Screen resolution

Most manufactures offer 3 different types resolutions 1080p (Progressive Scan) which equates to 1,920 x 1,080 pixels “This is the way to go if you can afford it”, next in line is 720p (Progressive Scan) which equates to 1280 x 720 pixels. 3rd in line is 1080i which equates to 1,920 x 1,080 (interlaced) pixel resolution but conveys the images in an interlaced format (which gives it the “I” in 1080i for interlaced). Most HDTV channels broadcast in the last 2 resolutions listed, 720p or 1080i is the standard broadcast formats for most cable, direct TV™, and satellite feeds, the deciding factor should include your price range and what type of media you will be viewing. If you plan on viewing Blu-ray-disc™ then 1080p will do you lots of justice! The only down fall is the hit to your pocket book. Remember EDTV Resolution 840 X 180 has been discontinued.

There are other resolutions out there but we wanted to cover mostly

What you will be encountering in today’s market. For more information on resolution and native resolution check out our Resolution How Page.

Response time

Plasma television response times are almost instantaneous, and are not a deciding specification as with LCD TV's, this is because plasma televisions “like fluorescent lights” are a gas and the phosphors are illuminated instantly or within 0.002 milliseconds thus making them much faster then the fastest LCD refresh rate clearly giving plasma an edge in this arena! You might ask; how can a faster response time plasma TV benefit me vs a LCD TV? Simple, a faster response time means less motion blur “judder” in fast action scenes like sports, action movies and intense gaming systems. Matter a fact, you should not experience any motion blur with a plasma Tv, while you should experience some motion blur with an LCD television. Recent advances in LCD technology Some High end LCD TV response times go as low as 2 ms.

Contrast Ratio

Is the measurement used to show the difference in light intensity between the brightest white and the darkest black.

 

Example: Contrast ratio will read something like, 2000:1 or 5000:1, and can even go as high as 10000:1 and getting higher as technology advances! The higher the contrast ratio “left number” the blacker the blacks will be to whites and will result in fewer areas that look gray but are suppose to be black. Remember this is an important number but you should always judge by your eyes. Simply put, what looks good is good! And use the contrast ratio as a guide to get started in the right direction. Plasma TV’s generally have a better contrast, resulting in deeper richer colors. The Blacks are black with little to no gray shading where it’s suppose to be black. This results in spending less money for a better contrast. I would suggest determining your price range first, selecting your desired screen size second. Then go to your local HDTV store and view your desired screen size, Doing this will assure you get the right size HDTV with the best looking picture for your budget! Remember a good balance between HDTV features is the smart way to go! Check out our expert review matrix for great combinations of features, prices, sizes Etc.

Viewing Angle

Is not a huge factor to consider, especially since plasma’s are known for there extra wide viewing angles, making plasmas ideal for off angle viewing! You can usually sit at least 75° off the axis and still see a perfect picture. Although most manufactures state that there viewing angle is much more than this you will notice little decrease in color saturation, brightness and contrast in the picture when exceeding the maximum viewing angles. Plasma televisions offer greater viewing angles than LCD’s. This is due to it individual pixel layout. Most manufactures offer 150° up to 177° of viewing angle. Yes plasma takes the ball in this arena. Check out LCD Vs. Plasma or our Expert Review Matrix.

General characteristics

Plasma displays are bright (1,000 lux or higher for the module), have a wide color gamut, and can be produced in fairly large sizes—up to 381 cm (150 inches) diagonally. They have a very low-luminance "dark-room" black level compared to the lighter grey of the unilluminated parts of an LCD screen. The display panel is only about 6 cm (2.5 inches) thick, while the total thickness, including electronics, is less than 10 cm (4 inches). Plasma displays use as much power per square meter as a CRT or an AMLCD television.[citation needed] Power consumption varies greatly with picture content, with bright scenes drawing significantly more power than darker ones, as is also true of CRTs. Nominal power rating is typically 400 watts for a 50-inch (127 cm) screen. Post-2006 models consume 220 to 310 watts for a 50-inch (127 cm) display when set to cinema mode. Most screens are set to 'shop' mode by default, which draws at least twice the power (around 500-700 watts) of a 'home' setting of less extreme brightness.[3] Panasonic has greatly reduced power consumption by using Neo-PDP screens in their 2009 series of Viera plasma HDTVs. Panasonic claims that PDPs will consume only half the power of their previous series of plasma sets to achieve the same overall brightness for a given display size. The lifetime of the latest generation of plasma displays is estimated at 100,000 hours of actual display time, or 27 years at 10 hours per day. This is the estimated time over which maximum picture brightness degrades to half the original value.

 

Plasma displays have drawbacks other than power consumption. They are often criticized for reflecting more ambient light than LCD displays. The front screen is made from glass, which reflects more light than the material used to make an LCD screen, which results in glare from reflected objects in the viewing area. Companies such as Panasonic coat their newer plasma screens with an anti-glare filter material.[citation needed]. Currently, plasma panels cannot be economically manufactured in screen sizes smaller than 32 in. Although a few companies have been able to make plasma EDTVs this small, even fewer have made 32 in plasma HDTVs. With the trend toward larger and larger displays, the 32 in screen size is rapidly disappearing. Though considered bulky and thick compared to their LCD counterparts, some sets such as Panasonic's Z1 and Samsung's B860 series are as slim as one inch thick making them comparable to LCDs in this respect.

 

Competing displays include the CRT, OLED, LCD, DLP, SED, LED, and FED flat panel displays. Advantages of plasma display technology are that a large, very thin screen can be produced, and that the image is very bright and has a wide viewing angle. The viewing angle characteristics of plasma displays and flat-face CRTs are essentially the same, topping all LCD displays, which have a reduced viewing angle in at least one direction. Plasma TVs also do not exhibit an image blur common in many LCD TVs.

Plasma display pros and cons

 

Advantages

 

   * Slim profile

   * Can be wall mounted

   * Lighter and less bulky than rear-projection televisions

   * Achieves better and more accurate color reproduction than LCDs (68    

       billion/236 versus 16.7 million

   * Produces deep, true blacks allowing for superior contrast ratios (up to      

       1:2,000,000)

   * Far wider viewing angles than those of LCD (up to 178°); images do not    

       suffer from degradation at high angles unlike LCDs

   * Virtually nonexistent motion blur, thanks in large part to very high refresh  

       rates and a faster response time, contributes to the superior performance of   

       plasma displays when displaying video and film content, for example sports,

       action movies, etc., that contains significant amounts of rapid motion

 

Disadvantages

 

   * Older[clarification needed] models are susceptible to screen burn-in and  

       image retention (however, newer models have green phosphors and built-in

       technologies to eliminate this, such as pixel shifting)

   * Phosphors in older[clarification needed] models lose luminosity over time,

       resulting in gradual decline of absolute image brightness (newer models are

       less susceptible to this, having lifespans exceeding 60,000 hours, far longer  

       than older CRT technology)

    * Susceptible to "large area flicker"

   * Generally do not come in smaller sizes than 32 inches

    * Susceptible to reflection glare in bright rooms

   * Heavier than LCD due to the requirement of a glass screen to hold the gases

   * Use more electricity, on average, than a LCD TV

   * Do not work as well at high altitudes due to pressure differential between the

       gases inside the screen and the air pressure at altitude. It may cause a

       buzzing noise. Manufacturers rate their screens to indicate the altitude

       parameters.

Native plasma television resolutions

Fixed-pixel displays such as plasma TVs scale the video image of each incoming signal to the native resolution of the display panel. The most common native resolutions for plasma display panels are 854×480 (EDTV), 1,366×768 or 1,920×1,080 (HDTV). As a result picture quality varies depending on the performance of the video processor and the up-scaling and downscaling algorithms used by each display manufacturer.

 

Enhanced-definition plasma television

Early plasma televisions were enhanced-definition (ED) with a native resolution of 840×480 (discontinued) or 853×480, and down-scaled their incoming high definition signals to match their native display resolution.

 

Resolutions

 

   * 840×480

   * 853×480

 

Hi-definition plasma television

 

Early hi-definition (HD) plasma displays had a resolution of 1024x1024 and were Alternate Lighting of Surfaces (ALiS) panels made by Fujitsu/Hitachi.

These were interlaced displays, with non-square pixels.

 

Modern HDTV plasma televisions usually have a resolution of 1,024×768 found on many 42 in plasma screens, 1,280×768, 1,366×768 found on 50 in, 60 in, and 65 in plasma screens or 1,920×1,080 found in plasma screen sizes from 42 in to 103 in. These displays are usually progressive displays, with square pixels, and will up-scale their incoming standard-definition signals to match their native display resolution.

 

Resolutions

 

   * 1,024×1,024

   * 1,024×768

   * 1,280×768

   * 1,366×768

   * 1,920×1,080

How plasma displays work

 

The xenon, neon, and helium gas in a plasma television is contained in hundreds of thousands of tiny cells positioned between two plates of glass. Long electrodes are also put together between the glass plates, in front of and behind the cells. The address electrodes sit behind the cells, along the rear glass plate. The transparent display electrodes, which are surrounded by an insulating dielectric material and covered by a magnesium oxide protective layer, are mounted in front of the cell, along the front glass plate. Control circuitry charges the electrodes that cross paths at a cell, creating a voltage difference between front and back and causing the gas to ionize and form a plasma. As the gas ions rush to the electrodes and collide, photons are emitted.

 

In a monochrome plasma panel, the ionizing state can be maintained by applying a low-level voltage between all the horizontal and vertical electrodes–even after the ionizing voltage is removed. To erase a cell all voltage is removed from a pair of electrodes. This type of panel has inherent memory and does not use phosphors. A small amount of nitrogen is added to the neon to increase hysteresis.

 

In color panels, the back of each cell is coated with a phosphor. The ultraviolet photons emitted by the plasma excite these phosphors to give off colored light. The operation of each cell is thus comparable to that of a fluorescent lamp.

 

Every pixel is made up of three separate subpixel cells, each with different colored phosphors. One subpixel has a red light phosphor, one subpixel has a green light phosphor and one subpixel has a blue light phosphor. These colors blend together to create the overall color of the pixel, the same as a triad of a shadow mask CRT or color LCD. Plasma panels use pulse-width modulation to control brightness: by varying the pulses of current flowing through the different cells thousands of times per second, the control system can increase or decrease the intensity of each subpixel color to create billions of different combinations of red, green and blue. In this way, the control system can produce most of the visible colors. Plasma displays use the same phosphors as CRTs, which accounts for the extremely accurate color reproduction when viewing television or computer video images (which use an RGB color system designed for CRT display technology).

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LIFE-SPAN | USING IT FOR? | SPECIFICATIONS | ASPECT RATIO | RESOLUTION

RESPONSE TIME | CONTRAST RATIO | VIEWING ANGLE | GENERAL CHARACTERISTICS PLASMA TV PRO’S & CONS | NATIVE RESOLUTION

HOW DO PLASMA DISPLAYS WORK? | PLASMA HDTV BASICS

PLASMA-HOW-IT-WORKS

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