Plasma and LCD displays work in two very different ways. A plasma TV is sometimes called an "emissive" display while an LCD panel has a "transmissive" display. Let's explore the differences in these two technologies.
How a Plasma TV works
A plasma display consists of two transparent glass panels with a thin layer of pixels sandwiched in between. Each pixel is composed of three gas-filled cells or sub-pixels (one each for red, green and blue). A grid of tiny electrodes applies an electric current to the individual cells, causing the neon and xenon gas in the cells to ionize. This ionized gas (plasma) emits high-frequency UV rays, which stimulate the cells' phosphors, to glow the desired colour.
Because a plasma panel is illuminated at the sub-pixel level, images are extremely accurate, and the panel's light output is both high and consistent across the entire screen area. Plasma TVs also provide very wide horizontal and vertical viewing angles. Picture quality looks sharp and bright from virtually anywhere in the room.
Most flat-panel TVs are progressive displays - they draw the entire image at once. Panasonic's 1080p plasma displays illuminate over two million pixels for true high-definition clarity, deeper blacks and warmer colours.
How an LCD TV works
Light in an LCD panel isn't created by the liquid crystals themselves; instead, a light source behind the panel shines light through the display, while a white diffusion panel behind the LCD redirects and scatters the light evenly to ensure a uniform image.
The display consists of two polarizing transparent panels and a liquid crystal solution sandwiched in between. The screen's front layer of glass is etched on the inside surface in a grid pattern to form a template for the layer of liquid crystals. Liquid crystals are rod-shaped molecules that bend light in response to an electric current - the crystals align so that light cannot pass through them. Each crystal acts like a shutter, either allowing light to pass through or blocking the light. This pattern of transparent and dark crystals forms the image.
LCD TVs use the most advanced type of LCD, known as an "active-matrix" LCD. This design is based on thin film transistors (TFT). Their job is to rapidly switch the LCD's pixels on and off. In a colour LCD TV, each colour pixel is created by three sub-pixels with red, green and blue color filters.
One of the biggest challenges for LCD TV manufacturers has been speeding up the pixel response time (how fast an individual pixel switches from fully off to fully on) to ensure that fast-moving objects don't exhibit "motion lag" or ghosting. It's especially critical for larger-screen LCD TVs where much of the viewing will be DVD movies and/or HDTV.
An important difference between plasma and LCD technology is that an LCD screen doesn't have a coating of phosphor dots (colours are created through the use of filters). That means you'll never have to worry about image burn-in, which is great news, especially for anyone planning to connect a PC or video game system. LCD TVs are extremely energy-efficient, typically consuming 60% less power than comparably-sized tube-type TVs.
Which type is right for you?
Plasma TVs have been around longer than LCD TVs, and their technology is a little further along. Plasma screens use a phosphor coating like tube TVs, so they have the natural colour we're used to with tube models.
Plasmas have better contrast and black level performance than LCDs, and offer slightly wider viewing angles. People often describe plasma's picture quality as richer or more "cinematic," so it's a great choice for a home theatre, or your main TV.
A plasma TV might be for you if:
You want really rich, warm colors and deep blacks
You like to watch sports and other fast-action TV
You'll be sitting off-axis when you watch TV or movies
Your viewing room doesn't have a lot of ambient light, or you can easily reduce the light by closing blinds.
If you're looking at screen sizes over 42", Plasma would be the better choice.
A flat-panel LCD TV might be for you if:
You watch a lot of TV shows or play lots of video games with static images on the screen for extended periods of time, multiple days a week
Your TV room is relatively bright, or you do a lot of daytime viewing
Plasma and LCD Research
In Australia, Great Britain and several other European markets, independent surveys have been conducted on the perception of Plasma versus LCD technology.
Initially 56% of those surveyed thought LCD would offer better picture quality than Plasma with 42% thinking Plasma was better.
These viewers were then shown both Plasma and LCD TVs in normal home lighting conditions and the swing to Plasma was very marked - up to 69%, with only 31% believing that LCD looked better.
Panasonic recognise the relative strength of both technologies.
VIERA Plasma's are the choice for living rooms and larger spaces. With their wide viewing angle, deep rich colour, VIERA Plasma sets also stand up to the rigour of family life with their full glass front.
Panasonic LCD sets, manufactured in a range from 32" to 42", have two key technologies of Motion Picture Pro and Intelligent Scene Controller.
Motion Picture Pro takes a 50Hz signal and doubles it by creating an intermediate frame between each original frame, thus making the signal 100Hz and greatly reducing motion blur, a previously common problem with LCD.
Intelligent Scene Controller adjusts the level of backlight on a frame by frame basis. It will bring up the backlight for a bright scene and lower it for a darker scene, bringing a massive 8,500:1 contrast ratio.
These sets stand up extremely well in daytime lighting and with their smaller sizes (32"-42") suit smaller rooms.
LCD and Plasma
Because plasma TVs are self-illuminating, the images are beautiful when viewed from any angle. Black areas do not fade, and colours remain almost identical regardless of where the viewer is positioned.
Take a look at the Panasonic Viera range of Plasma & LED LCD TVs to find which best suits your viewing needs.
- See more at: panasonic.co.nz
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