Understand basic terminology next time you go television shopping.
Electronics terminology is filled with jargon. Terms commonly used and understood by people in the industry are often unknown or misinterpreted by those outside it. Given the large and potentially confusing range of features and acronyms thrown around in literature and product packaging, it's important to arm yourself with understanding of a few key terms to hold a cogent discussion with a salesperson or to conduct research.
Refresh Rate
Refresh rate is expressed in numerical fashion, such as 120, 240, 480 and 600 hertz, and describes the ability of a television to process fast motion. Originally, projectors and digital televisions were limited to 60 hertz, sometimes causing things like soccer balls and speeding cars to leave trails behind them. Known as motion blur, these trails are potentially distracting. Televisions and projectors with high refresh rates process images differently, making that motion smoother and more realistic. The higher the refresh rate, the smoother the images appear.
Resolution
Numbers like 1080p, 720p, and 480p are shorthand for actual screen resolutions. All digital projectors and television images are comprised of individual picture elements, known as pixels. These small rectangular blocks are arrayed in a certain number horizontally and vertically. Televisions with 1080p resolution, for example, have a horizontal resolution of 1920 pixels by 1080 vertical pixels. These pixels are "drawn" at once, called progressive scanning. This is where the "p" comes in when discussing the resolution. The higher the resolution number, the smoother the image, allowing you to sit closer without seeing individual pixels.
Plasma TV
Plasmas use electrically excited Neon and Xenon gasses to illuminate the phosphors in each encapsulated pixel to generate vibrant images and deep blacks. LCD and its LED variant are virtually immune to image retention, or "burn-in" caused by static high contrast logos and graphics. Plasmas are still capable of this, although a variety of features in plasma sets work to mitigate the issue. Such technologies involve shifting the screen one or two pixels at a time, and never keeping the same place illuminated long enough to form a retained image.
LCD and LED
Televisions and projectors that use liquid crystal picture elements are called LCDs. These sets have liquid crystal elements that respond to electrical charge, twisting and untwisting to allow certain shades of color and light through. Many of these televisions use light emitting diodes as the light source. Cold Cathode Lighting, or CCFL, is a version of florescent lighting arrayed behind the screen. CCFL lighting is less energy efficient than LED, and offers a shorter overall lifespan. Color-tinted LEDs are able to individually dim, potentially offering richer blacks and color saturation. Most higher-end LCD televisions incorporate LED backlighting. LED LCDs are the same basic technology, using a different light source than before, while offering ever-thinning cabinet thicknesses and energy efficiency.
DLP
Sets and projectors employing Texas Instruments' Digital Light Processing technologies are referred to as DLP. These sets are lightweight tabletop-mounted models, ranging in size from 50 inches up to 80 inches. Televisions using this technology use a bright light source, such as a lamp or LED array to project images. This light is bounced off a Digital Micromirror Display chip that incorporates millions of small mirrors, each representing one pixel. After reflecting off of the DMD chip, the light passes through a prism for further color processing. DLP sets can be found in large screen sizes that are much less expensive proportionally than flat panel technologies. However, these sets are deeper, and cannot be wall mounted. DLP sets are immune to burn-in, do not have three tubes requiring alignment like bulkier cathode ray tube or CRT sets and are energy efficient. Since DLP bounces light off of mirrors as opposed to passing it through LCD panels, DLP projectors are typically brighter overall.
HDMI
Short for High Definition Multimedia Interface, this single-cable protocol transmits high definition video and uncompressed audio. This audio and video standard is also popular among content owners, whose material is encrypted digitally on the HDMI cable to prevent unauthorized copying. HDMI is reminiscent of a computer USB cable, and is a potentially inexpensive medium for connecting your home theater components. HDMI replaces individual audio and video cabling, reducing cable clutter behind an equipment or TV stand. For a high definition source, this means the red, blue and green component video cables and a separate digital audio cable are replaced by a single, thinner cable with more data-handling capability.
Tags: light source, audio video, energy efficient, liquid crystal, picture elements
