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Benefits of a Computer Monitor (back to top)

 

There is almost no task that a computer user can perform in the absence of a monitor. This accessory is the key component to enable the user to know what he is doing and what is happening within the internal workings of the computer system. In order to work in any software application, ranging from the most basic word processor to the advanced graphics and animation packages, the monitor plays an indispensable role. Not a single meaningful keyboard stroke or mouse click is possible without the computer operator having his eyes glued to the monitor.

 

In addition to the normal computer operations and Internet surfing activities, computer monitors can even be used as televisions. Insertion of a TV tuner card into the slot provided can even enable the system to receive television signals, images of which can be viewed on the monitor. With the recent proliferation of Internet TV, worldwide streaming television programs can be viewed on the monitor as easily as you view a spreadsheet. Even movies stored on the hard drive of the computer or from DVDs can be enjoyed on the computer which can double up as a second television in a household.

 

The world has been witness to many innovative and ingenious computer-generated graphic and animation creations, some even having made their way into blockbuster Hollywood movies. This creativity would not have reached fruition, if the talented artists could not see what they were doing every minute step of the way, something that only the computer monitor could provide.

 

Taking into consideration the long number of hours spent in front of the computer in today's cyber world, both at home and at the office, the safety factor has not been ignored. Nowadays, all computer monitors have to pass stringent tests as far as radiation emission and glare is concerned. Monitors are now designed to be easy on the eyes, and minimize incidents of eye strains and headaches. The angle of most monitors can be adjusted from the base, and can be tilted as per the requirements of the user.

 

1. How Monitors Function (back to top)

 

As we have seen above, the basic functionality of a computer monitor depends on the transmission of signals from the computer to the monitor. In order to understand the working of monitors, we will first need to understand the fundamentals of this signal transmission. Computer-monitor data transmission happens in one of two ways: analog transmission or digital transmission. Below we will discuss the key features of each of these transmission modes:

 

• Analog Transmission: This type of signal propagation is used in CRT monitors as CRT technology most often does not support digital transmission. Analog transmission implies that signals are transmitted in the form of incessant electric signals and waves, having variable intensities. However, since output from the computer is digital, an expansion card called the video adaptor, video card, or graphics card converts the digital information reaching it from the computer into analog form and sends this data to the monitor through a Video Graphics Adaptor (VGA) cable. This cable has three distinct connectors for red, green, and blue colors and another two connectors for handling horizontal and vertical synchronization. A combination of data from all of the connectors forms the complete video signal.
• Digital Transmission: This transmission mode, using the Digital Video Interface (DVI), implies data transfer from the computer to the monitor in digital format itself, thereby not requiring any change to the analog form. The DVI transmission mode works on the 'Transition Minimized Differential Signaling' (TMDS) principle which uses a transmitter in the video adaptor to convey digital signals to a receiver on the monitor. Depending on the resolution and refresh rate of the monitor, the signal utilizes the entire bandwidth available to ensure speedy data transfer between computer and monitor. Digital signals generally result in better image clarity.

 

DVI cables can be either single link cables using only one TMDS transmitter that generates a 1020 x 1080 image or dual link cables using two transmitters that generate a 2048 x 1536 image.

 

Additionally, DVI connectivity is of two types; DVI-Digital (DVI-D) that supports only digital data transmission and DVI-Integrated (DVI-I) that supports digital and analog signals.

 

2. Three Main Types of Monitors (back to top)

 

• Liquid Crystal Display (LCD): These monitors consist of two layers of polarized glass with liquid crystal spread in between. An electric field generated, enables intelligent restriction of the passage of light, resulting in the formation of the relevant colors and images. LCD screens work using two technologies: active matrix and passive matrix. Active matrix technology uses a Thin Film Transistor (TFT) which consists of an array of small transistors and capacitors spread over the glass. Only the transistor or capacitor corresponding to a pixel which needs to be displayed receives the charge. Passive matrix technology, on the other hand, incorporates a metal grid which charges the relevant pixel. These signals together form the image on the display screen. LCD monitors are popular as they are lighter and have lower power consumption.
• Cathode Ray Tube (CRT): These monitors use the same technology on which traditional televisions work. The monitor consists of a surface coated with millions of phosphor granules. These granules which are composed of the three main constituents of all colors: red, green, and blue glow when subjected to an electron beam. The CRT apparatus consists of a negatively charged heated filament placed at one end of a vacuum tube, which emits electrons that get attracted to the positively charged phosphor screen which, in turn, glows when hit by the electrons. An actual viewable picture is formed through the following three techniques:

 

• Shadow Mask: This is a thin metal shield having miniscule holes, which helps to control the intensity as well as the direction of the electron beam falling on the phosphor surface, resulting in the correct color and image being displayed.
• Aperture Grill: This technique, popularized by the Sony Trinitron technology, uses a grill of vertical wires through which the electron beam passes to collide with the phosphor coated screen. This technique that incorporates a flat faceplate as compared to the curved faceplate used in the Shadow mask, generates a clearer image, but is more expensive.
• Slot Mask: This technique uses a combination of the two techniques above using a shield having vertical slots through which the electron beam travels to make contact with the phosphor screen. This image generated through this technique is brighter.
• Plasma: These monitors are comprised of two layers of glass having neon-xenon gas in between them, interspersed with horizontal and vertical electrodes. In monochrome monitors, after being subject to an electric current, these electrodes prompt the gases to ionize and release photons. A built-in memory eliminates the need for phosphors. In the case of a colored monitor, the electrodes are charged at an incredibly fast rate, resulting in a surge of charged particles, which excite the gas atoms to emit ultraviolet photons. It is these photons - miniscule particles of light energy, which result in the image being formed on the screen.

 

3. Purchasing Criteria (back to top)

 

With the variety of monitors sold in the market at present and the rapid advances in technology, deciding on a monitor perfectly suited to your requirements can be a tough proposition. To make your task easier, we have a listed a few basic characteristics that you need to look for when making a purchase:

 

• Size/Weight: This depends both on the space available to you to keep your monitor as well as on what you commonly use your computer for. It goes without saying that, if you intend to use your computer for graphic intensive work like fashion designing, 3D animation, or CAD/CAM engineering work where detail is of paramount importance, having a large monitor would make more sense. Also, since images and text are larger in a wider monitor, there is less strain on the eyes. In this parameter, an LCD monitor scores over a CRT monitor as it weighs much less than a CRT monitor, grabs less space and also consumes less power. Also, the screen size of a 17"LCD monitor may be larger than a similarly sized CRT monitor. This is because, in the case of a CRT monitor the size is measured diagonally across the screen taking into consideration the plastic frame too, whereas in an LCD monitor only the actual screen is measured.
• Resolution: Resolution, measured in dots per inch (dpi) or in pixels per inch (ppi), denotes the concentration of pictorial detail that is displayed on the screen. The greater the number of pixels supported on the screen, better the image quality. Also, a monitor with a higher resolution makes text or images on the screen look smaller. While LCD monitors show optimal quality at their intrinsic resolution, CRT monitors can work at resolutions higher than their native resolutions.
• Refresh Rate: This is the rate at which every portion of the screen display is re-painted, which is a built-in feature of most monitors. If the refresh rate is too slow, the user may be subjected to a flickering screen which may be detrimental to the eyes. Sometimes, higher refresh rates may have to be traded for lower resolution.
• Color Depth / Bit Depth: Color depth refers to the number of colors supported by the monitor. Greater the number of bits better is the color display. LCD monitors use a combination of the three basic colors: red, green, and blue to offer 16. 8 million colors. Color depth for CRT monitors can range from 1 bit for a black and white display, 8 bits for 256 colors, and 24 bits for true color, thereafter leading to even higher color depths. Bit depth represents the number of bits per pixel.
• Dot Pitch: This is the distance between two pixels in a CRT monitor or between two LCD cells in an LCD monitor. Greater dot pitch translates into better picture quality.
• Pixel Response Time: This measure is an indication of the time required for the pixel to take on a new color. Slow response times can result in blurring or double images being formed.
• Brightness: This is an indication of how much light an image exudes, measured in nits, 1 nit being equivalent to 1 candle per square meter.
• Contrast: This indicates the variance in the color and brightness of an image in the foreground as compared to the background. Depicted as a ratio, for normal applications a contrast of 400:1 is sufficient while more sophisticated monitors offer contrasts as high as 1000:1.
• Aspect Ratio: This ratio represents the ratio between the width of the monitor to its height. The most common ratio is 4:3. Some more advanced monitors will offer aspect ratios of 16:9, which is considered 'Widescreen'.
• Viewing Angle: This is a measurement of the maximum angle away from the side of the monitor that the user can move and still get a clear picture of the image on the monitor. CRT monitors usually have a greater viewing angle as compared to LCD monitors. Most computer monitors can be twisted and swiveled as per the users comfort levels.
• TCO Certification: In order to ensure that the electromagnetic radiations emitted by monitors fall within safe limits, all monitors need to undergo strict emission tests. TCO certification implies that the monitor passes all the tests as far as emission and energy consumptions are concerned.
• Connectivity: Some monitors may have USB ports or hubs which allow connectivity to peripheral devices such as a mouse, printer, or a scanner. These ports offer extra connectivity in addition to the port at the back of the computer.

 

4. Making the Decision (back to top)

 

After identifying your needs with regards to the various features mentioned above, you should compare different computer monitors at a comparison shopping site such as www.smarter.com. It is advisable to consider all the above monitor properties before singling out the computer most suited to your requirements. Some of the latest technologies include: touch screen monitors which allow the user to navigate through the various applications by touching the screens, wireless monitors which allow connectivity to a computer without use of a cable, along with television and HDTV integration, which allows a monitor to act as a High Definition television.

 

Another factor to consider for a delicate electronic device like a monitor is the warranty, which may vary from 1 to 5 years. Before you purchase, it is worth noting what is covered under the warranty.

 

In order to ensure long trouble-free service from your monitor, maintenance of the device is very important. Ensure that you get the user manual and follow the instructions mentioned therein for usage and care.

 

Buying the right monitor for your needs requires time in researching and evaluating the various models and their specifications. The trick is to strike the perfect balance between price and functionality; and the best way to begin is to find out exactly what your needs are. Hopefully now you have more information to help make your purchasing decision more informed, now go find a great computer monitor!