The Technical Aspects Of Monitor And Its Evaluation Criteria

By: Smruti Ranjan Sarangi

Monitor is another term for display screen. The term monitor, however, usually refers to the entire box, whereas display screen can mean just the screen. In addition, the term monitor often implies graphics capabilities.

There are many ways to classify monitors. The most basic is in terms of color capabilities, which separates monitors into three classes:

1- Monochrome: Monochrome monitors actually display two colors, one for the background and one for the foreground. The colors can be black and white, green and black, or amber and black.

2- Gray-scale : A gray-scale monitor is a special type of monochrome monitor capable of displaying different shades of gray.

3- Color: Color monitors can display anywhere from 16 to over 1 million different colors. Color monitors are sometimes called RGB monitors because they accept three separate signals—red, green, and blue.

After this classification, the most important aspect of a monitor is its screen size. Like televisions, screen sizes are measured in diagonal inches, the distance from one corner to the opposite corner diagonally. A typical size for small VGA monitors is 14 inches. Monitors that are 16 or more inches diagonally are often called full-page monitors. In addition to their size, monitors can be either portrait (height greater than width) or landscape (width greater than height). Larger landscape monitors can display two full pages, side by side. The screen size is sometimes misleading because there is always an area around the edge of the screen that can't be used. Therefore, monitor manufacturers must now also state the viewable area—that is, the area of screen that is actually used.

The resolution of a monitor indicates how densely packed the pixels are. In general, the more pixels (often expressed in dots per inch), the sharper the image. Most modern monitors can display 1024 by 768 pixels, the SVGA standard. Some high-end models can display 1280 by 1024, or even 1600 by 1200.

Another common way of classifying monitors is in terms of the type of signal they accept: analog or digital. Nearly all modern monitors accept analog signals, which is required by the VGA, SVGA, 8514/A, and other high-resolution color standards.

A few monitors are fixed frequency, which means that they accept input at only one frequency. Most monitors, however, are multiscanning, which means that they automatically adjust themselves to the frequency of the signals being sent to it. This means that they can display images at different resolutions, depending on the data being sent to them by the video adapters.

Other factors that determine a monitor's quality include the following:

1- Bandwidth: The range of signal frequencies the monitor can handle. This determines how much data it can process and therefore how fast it can refresh at higher resolutions.
2- Refresh rate: How many times per second the screen is refreshed (redrawn). To avoid flickering, the refresh rate should be at least 72 Hz.
3- Interlaced or noninterlaced: Interlacing is a technique that enables a monitor to have more resolution, but it reduces the monitor's reaction speed.
4- Dot pitch : The amount of space between each pixel. The smaller the dot pitch, the sharper the image.
5- Convergence: The clarity and sharpness of each pixel.

TOUCH SCREEN MONITOR

A touchscreen is an easy to use input device that allows users to control PC software, DVD video, camera etc. by touching the display screen. We manufacture and distribute a variety of touch screen related products. A touchscreen is an input device that allows users to operate a PC, camera etc. instruments by simply touching the display screen. Touch input is suitable for a wide variety of computing applications. A touchscreen can be used with most systems as easily as other input devices such as track balls or touch pads.

How Does a Touchscreen Work? A typical touchscreen input system is basically an input device like a mouse , trackpad or ball pens etc.. A touchscreen system is made up of a touch sensor, a controller card, and a software driver.

What Are Touchscreens Used For? Touchscreen systems are being used in a variety of applications, including point-of-sale systems, public information displays, industrial control systems, and more.

Touchscreen monitors have become more and more commonplace as their price has steadily dropped over the past decade. There are three basic systems that are used to recognize a person's touch: 1- Resistive 2- Capacitive 3- Surface acoustic wave

The resistive system consists of a normal glass panel that is covered with a conductive and a resistive metallic layer. These two layers are held apart by spacers, and a scratch-resistant layer is placed on top of the whole setup. An electrical current runs through the two layers while the monitor is operational. When a user touches the screen, the two layers make contact in that exact spot. The change in the electrical field is noted and the coordinates of the point of contact are calculated by the system. Once the coordinates are known, a special driver translates the touch into something that the operating system can understand, much as a computer mouse driver translates a mouse's movements into a click or a drag.

In the capacitive system, a layer that stores electrical charge is placed on the glass panel of the monitor. When a user touches the monitor with his or her finger, some of the charge is transferred to the user, so the charge on the capacitive layer decreases. This decrease is measured in circuits located at each corner of the monitor. The computer calculates, from the relative differences in charge at each corner, exactly where the touch event took place and then relays that information to the touchscreen driver software. One advantage that the capacitive system has over the resistive system is that it transmits almost 90 percent of the light from the monitor, whereas the resistive system only transmits about 75 percent. This gives the capacitive system a much clearer picture than the resistive system.

On the monitor of a surface acoustic wave system, two transducers (one receiving and one sending) are placed along the x and y axes of the monitor's glass plate. Also placed on the glass are reflectors—they reflect an electrical signal sent from one transducer to the other. The receiving transducer is able to tell if the wave has been disturbed by a touch event at any instant, and can locate it accordingly. The wave setup has no metallic layers on the screen, allowing for 100-percent light throughput and perfect image clarity. This makes the surface acoustic wave system best for displaying detailed graphics (both other systems have significant degradation in clarity).

Another area in which the systems differ is in which stimuli will register as a touch event. A resistive system registers a touch as long as the two layers make contact, which means that it doesn't matter if you touch it with your finger or a rubber ball. A capacitive system, on the other hand, must have a conductive input, usually your finger, in order to register a touch. The surface acoustic wave system works much like the resistive system, allowing a touch with almost any object—except hard and small objects like a pen tip.

As far as price, the resistive system is the cheapest; its clarity is the lowest of the three, and its layers can be damaged by sharp objects. The surface acoustic wave setup is usually the most expensive.

MONITORING TOOLS

There are many types of tools, devices, instruments and software available in market for monitor. Some of the tools names I am giving below:

Blue eye 2 monitor calibration tool For accurate professional color rendering, the LaCie blue eye 2 with hardware-assisted LCD and CRT monitor calibration is an easy, compatible color evaluation tool.

Monitor with Built-In DVR and 4 Cameras Observe and record all your security activities with this all-in-one system. Includes monitor with built-in digital video recorder and 4 color.

Color Vision Spyder2PRO monitor calibration tool HP Hewlett Packard.

And many other tools available in market.

FLAT SCREEN MONITOR

You don't have to feel boxed in by today's selection of computer monitors. Nor must you purchase a space-swallowing monstrosity to view text and graphics. Modern-day monitors are an amalgam of fashion and functionality.

There are two main types of monitors: CRT flat-screen monitors and LCD flat-panel monitors.

Less expensive, cathode-ray tubes (CRTs) are the most common type of monitor. While earlier models have slightly rounded screens, today's flat-screen CRTs are quickly gaining in popularity.

Whereas the origins of CRT technology can be traced to television sets, liquid crystal displays (LCDs) have long been used in laptop computers. LCDs often deliver sharper and brighter images than their bulkier counterparts. And although they are traditionally more expensive than CRTs, LCDs are significantly dropping in price as they enter the mainstream market.

So is it better to stick to tried-and-true CRTs or jump on the LCD wave? Consider the following:

Save space on your desk

In today's world of home offices and cramped quarters, size matters. Choose a resolution to suit your needs. LCDs might save on space but CRTs offer better sightlines. In addition to supporting multiple resolutions, CRTs let users view images clearly from various angles. LCD monitors, on the other hand, often appear blurry or dim when viewed from the side.

There are graphics people who still prefer a very large CRT flat-screen display to an LCD monitor. Digital photography enthusiasts will appreciate LCDs' sharp and bright images, especially when enhancing and touching up digital photos. LCD monitors also prevent consumers from straining their eyes when staring at the screen, says Park.

Research upkeep and longevity

Whether your preference is a sturdy CRT or a lightweight LCD, both types of monitors enjoy an average lifespan of five to seven years.

Whereas CRT screens can be cleaned with a cloth, oil from a person's skin can leave tough-to-remove markings on an LCD screen. When purchasing an LCD monitor, be sure to ask a store clerk to point you in the direction of appropriate cleansing solutions and wipe-ups in order to extend the life of your monitor.

FLAT PANEL MONITOR

A flat panel monitor can refer to either a computer or television monitor that does not use cathode ray tube (CRT) technology, but commonly LCD or plasma technology. This allows the monitor to have a thin profile, which is how the flat panel monitor gets its name. Because of its light weight, small footprint, clarity and digital technology, the flat panel monitor has become the monitor of choice.

Prior to the flat panel monitor, the CRT monitor was standard. These monitors are easily recognizable by the bulging back or picture tube. Vacuum tube monitors are not only bulky and heavy, but they are environmentally unfriendly and emit more radiation than a flat panel monitor.

While there are many advantages to a flat panel monitor, there are also one or two potential disadvantages. A limited viewing angle can be one, although this is easily avoided by shopping discriminately, as the viewing range is included in the specifications of these products. A second potential disadvantage is being bound to the "native resolution."

A CRT monitor will display sharp text in any supported resolution, but a flat panel monitor only delivers perfectly clear text in the native resolution. On a 19-inch screen this might be 1280×1024 pixels. Switching to a lower resolution will make text appear slightly blurred or fuzzy.

Why would anyone want to switch to a lower resolution? In higher resolutions, images improve but they also become smaller. For instance, the icons on a desktop, toolbars within software, and menus within the operating system are all reduced at higher resolutions. Though many of these items can be adjusted up, some people prefer a lower resolution to get overall larger images on screen. This might be a particular concern for those with visual disabilities. In this case, one should carefully view the flat panel monitor prior to purchase to be sure the native resolution will be comfortable.

Flat panel monitors have decreased steadily in price while improving in quality. Gamers and video-editing professionals tended to avoid these monitors initially because of "ghosting" with fast moving graphics, but this is no longer an issue. A faster response time and increased viewing angle have made the flat panel monitor more popular than ever. With its clear digital picture, space-saving footprint, and ultra-light weight, the flat panel monitor is a welcome improvement over its CRT predecessor.

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