The Computer Revolution/Peripherals/Monitors
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[edit] Monitors
[edit] CRT
CRT also known as cathode ray tube monitors were the most widely used computer monitors until the release of LCD monitors. CRT monitors are inexpensive and easy to maintain, however CRT monitors develop glare from the surroundings and can cause reflection resulting in a poor quality for viewing. CRT monitors also are quite larger in comparison to LCD monitors . The reason for the size of the CRT monitors is due to the same technology employed in some televisions screens. The Cathode ray projects a series of electrons onto a screen to ultimately produce an image, however the process of electrons to an image is much more tedious than a simple conversion.
[edit] History of the CRT
A German scientist Karl Ferdinand Braun in 1897 invented the first cathode ray tube. Braun introduced a CRT with a fluorescent screen, known as the cathode ray oscilloscope - an oscilloscope is an electronic display device containing a cathode ray tube (CRT), used to produce visible patterns that are the graphical representations of electrical signals. The screen would emit a visible light when struck by a beam of electrons. A Russian scientist Boris Rosing, in 1907, used a CRT in the receiver of a television system. Rosing also transmitted crude geometrical patterns onto the television screen and was the first inventor to do so using a CRT. The first practical signal generating tubes were invented by Vladimir K. Zworykin and Philo T. Farnsworth.
[edit] Other Advantages of the CRT Monitors
- Accurate color- CRTs provide richer color in a fuller variety than most LCDs
- Response time- may respond more quickly than some LCDs in regards to videos and action games
- Viewing angle- CRT provides brightness and color from a variety of different viewing angles
- Multiple resolutions
- Purchase price- CRTs are less expensive than LCDs
[edit] Disadvantages of the CRT Monitor
- Very heavy and large
- Uses large amounts of energy
- Generates excess heat
[edit] LCD
LCD or liquid crystal display screens are the newest and sharpest screens. Even though the use of LCD screens have been around for a long time, the technology has only been recently incorporated into the use of both televisions and computer monitors. The LCD screen uses rare characteristics that make it much more appealing than conventional CRT monitors. One of the key characteristics of LCD screens are the size advantage compared to a conventional CRT screen, a LCD screen does not employ the use of a cathode ray. But instead layers of filters and glass which polarize light and project onto liquid crystals which reveal sharp quality and excellent detail of the picture. Another interesting aspect of LCD screens is that there is almost no reflection of light from the surroundings into the screen.
[edit] Other Advantages of the LCD Monitors
- Brightness- the LCD monitor has a brightness of 250 to 300 nits
- No flicker- there is no flicker on a LCD, because it has a constant source of light over the whole screen
- Power consumption- consumes less power than the CRT, approximately one-third
- Ergonomics- the dimensions and the weight of the LCD permit it to consume less space. Example: mounting it on a wall
- Low emissions- LCDs cause no electromagnetic interference
Disadvantages of the LCD Monitor
- Blurry images outside native resolution
- Motion blur on fast moving images
- Some models have reduced color clarity
[edit] Digital Vs Analog
Analog and digital signals rely on two very different ways of translation. Analog is initially a digital signal that becomes translated by a graphics card into an analog signal which is than used for the display of the monitor. However the problem in this process is that quality and definition becomes “lost” in the translation from digital to analog, resulting in less sharpness and depth. Now a digital signal when properly connected to a DVI or digital video interface allows the digital signal to be directed right to monitor with no translation. This results in a higher quality picture that appears me crisp and clean.
