Electronic Displays: LCDs and LEDs - Coursework Example

Research into Electronic Displays No: Research into Electronic Displays An electronic display converts the electrical signal into a light form that has a certain meaning for example, numbers as in electronic clocks, pictures and videos as in CRTs, etc. the electrical signal that is to be transformed into a viewable manner through a displays has complex electronic circuitry that make the electric current or signal into a display element. Electronic displays have the much influence on our lives today. Nobody in the urban regions can neglect the influence of the electronic displays. From digital clocks and calculators to the electronic displays at the stadiums, electronic displays are everywhere. CRTs (Cathode Ray Tubes) are the conventional type of electronic displays, which are still utilized now a day. But in the most modern urban areas, Cathode ray tubes devices are replaced by modern electric display devices that are LCDs (Liquid Crystal Displays) and LEDs (Light emitting diode displays). The two important factors that an electronic display has is the number of pixels and resolution. However, other factors like brightness, contrast, aspect ratio, sharpness, hue and colors are important in determining the quality of the display. The most important applications of the displays are as the television, as displays with the computes and LED displays to display the text advertisement. In this research, I will determine the electronic display devices according to the technology, application and effect on the ecology and environment. Moreover, the methods through which the electronic displays can become useful for the economy as well as environment. In this research, I have utilized the qualitative method of research that makes the utilization of the previous data from different authors. The other method is a quantitative method that is also known as the scientific method. Different technologies are present to be categorized as electronic display devices. The most simple electronic display device is a combined LED (light emitting diode) combination board to represent words and numbers. LED indicators are common at some display centers to advertise text advertisements and at certain places it is utilized as the clocks. Some of the biggest electronic displays utilize the same technology as the simple ones. Cathode Ray Tube (CRT) The other common type of electronic display is a Cathode ray tube (CRT) displays. It is the first technology that is utilized to display the television transmission. At first, the CRT display devices have only two colors; black and white but as the time passed (Sheer 1993), CRT displays with multicolor have replaced the previous versions of the CRT display devices. Technology made the CRT display devices the most common type of display devices for the television transmission. The other intensive use of the CRT display devices was as the display for the computers. The bulk production of the CRT devices made them cheap but CRT display devices consume much energy as compared to other display devices. These display devices are originally made for the television transmission. In these devices two an anode is created at the screen of the tube and a cathode is created at the back side of the tube. The cathode is energized, which makes a bean of electrons that travel towards the anode or the screen. The anode side or the screen has a thin layer of phosphorus that has the ability to glow, when it knocked by the electron beam. Two separate beams, one moving from left to right and another moving from top to bottom. Two beams moving horizontally and vertically make the image (Whitaker 1994). The persistence of the phosphorus also plays an important role in the process of making an image. The beams move with such a speed that our eye is unable to detect the interval between the two images. At the cathode, a filament is utilized that is electrically energized to emit electrons. The electronic circuitry controls the beams and the give directions to the beams according to the signals provided to the electronic circuitry. The picture tube is the main components of a CRT display device which comprises an electron gun for making the electron beam. Nixie Tube Display In these types of displays the numeric characters are shown by lighting each numeric number. The lighting of the numeric character is dome by energizing the cathode terminal, which comprises the shape of the numeric character. A number of cathodes are utilized in the stacked form to represent different numeric characters at various depths. The anode is mostly a thin coat of transparent conducting oxides or some metallic elements that attract the cathode beam and the anode is located at the front side of the display. The display tube is seals the neon gas in the display tube cavity. The process of the lighting a character is also very simple. When a high DC voltage of about 200 Volts is given to the cathode to represent any numeric character, the inert element (neon) breaks and release energy near the cathode. The released energy is in the form of light that make the numeric character visible. The released light is most of time is a color between orange and red. The tubes were considered the technological breakthrough in the era, however, some defects in the device made them unpopular like if one cathode of particular numeric character stops working, the whole character stops working but in some other electronic displays as the seven segment displays (Sheer 1998), if one of the seven LEDs that make a character stops working the whole other LEDs work properly. Seven segment display is only a group of LEDs that are responsible to make a number. The negative of each of the LED is common but the positive sides of the LEDs have a different connection. When a positive signal is applied, the corresponding LED blinks and when a combine signal is applied to the seven segment display, a numeric character is the result. The main application of the nixie tube display is the Casio121-A and some others. Incandescent Filament Display In these types of displays the technology of the vacuum tube displays and nixie tube displays is utilized to display the numeric characters. It can also be given name as the previous versions of the seven segment displays as in the incandescent filament displays; a tungsten filament is utilized to be one segment of the display. As the voltage is applied across the terminals of the filament it produces light, which has the color of just like the old light bulbs, a yellowish color but it can be converted to any desired colors by the utilization of filters in the path of the light. As the voltage across the terminals of the filament varies the brightness of the light alters. Normally a potential difference of 3 to 6 volts DC is applied (Matsumoto 1990). The major reason behind the unpopularity of such display devices is that the response time of these devices is much lower. Gas Discharge Displays In these types of displays the most important factor is that they utilized the previous technology as that of the nixie tube display utilized but the display is just like a panel and sometimes also referred as the Plasma Display Panels (PLP). Just like the nixie tube displays, it also utilizes the neon gas with a little amount of mercury to seal a center layer. The back side of the plasma display is a ceramic sheet while the front side is a glass. The ceramic back holds the cathode while the anode is a transparent conducting oxide (mostly tin oxide and sometimes zinc oxide) deposited on the inner side of the glass. Each segment of the numeric character is formed from the cathode while the anode of each digit is different. When the potential difference is applied, the inert gas energizes and releases energy in the form of light and display the number. The color of the light and the potential is almost the same as in the nixie tube displays (Furr 1997). Electroluminescent Display Electroluminescent Display modules make use of some fluorescent material in the form of a thin coat that lays between insulated materials also known as the dielectric. The insulated material is kept between the two plates of glass which have a thin layer of transparent conducting oxide. When a potential is applied across the terminals of the transparent conducting oxides, the filament energized and emit light. The color of the light depends on the material utilized as the component with the phosphorus. This type of display has much resistance to atmospheric hazards as well as the harsh electrical break down and shock can make a little damage to the device. These are extensively utilized in the liquid crystal display panels as the back light. LED Displays Light emitting diode (LED) is very exceptional kind of diode that releases light when electricity applied to its anode and cathode. A common LED needs 3 volts DC at 10 milliamps for releasing light. LED generates red light, yellow light, blue light and green light. The LED was introduced in 1962 by Texas instruments. LED displays were first introduced in 1967 but were very high in amount. LED displays are used in calculators and LEDS are settled in calculators to make a seven-segment display or a dot matrix display (Furr 1997). Numeric Representation A dot matrix displays would create characters totally like to the dot matrix printer. A dot matrix consists of 4*7 or 5*7 displays. LEDs needs very much amount of energy and take very high amount as compared to LCDs. This has become the reason due to which it is ended in using in calculators. Liquid Crystal Display (LCD) Liquid crystal display (LCD) was first introduced in 1971 at RCA. LCDs are inactive displays as compared to LEDS and do not release light. As the consequence, LCDs require very low amount of energy and take less amount in its creation, that is why LCDs calculators are introduced that runs from the sun energy and are very low in amount as compared to LCDs. LCDs works from the liquid crystals (LC) to revolve polarized light as compared to a pair of crossed polarizer’s coated to the outer surface of the display. Basically there are two different kinds of LCDs displays that are used commonly in calculators that are, twisted nematic (TN) and super-twisted nematic (STN). TN displays twist polarized light to 90 degrees and have a restricted viewing angle (Furr 1997). STN displays were made to twist polarized light between 180 to 260 degrees consequential in improved difference and a wider viewing angle. A lot of other LCDs are developing like LCDs are widely used in laptops that are in full color version. These LCDS are consisting of double and triple twisted nematic (DSTN and TSTN) displays and the Active-matrix Thin-film Twisted Nematic and Metal-Insulated-Metal Twisted Nematic (TFT-TN and MIM-TN) displays. These highly developed displays are very high in amount for the calculator market. TN LCDs are commonly used in calculators because of their very low amount, thin size and necessity of low energy. As the time passed the technology in the displays produces more energy efficient and economically stable displays. The most modern type of displays is the LED displays, which have the capability to consume as low power as the device can. Moreover, the health concerns associated with the CRT display devices are lowered by the utilization of LEDs and LCDs. In this way, the latest display devices are more environment friendly as compared to the previous versions of the electronic displays. The other important concern is the economic sustainability of the display devices. The market is open of the newer versions of the display devices and everyday many manufacturing companies make thousands of display devices and people utilize the display devices far more than any other thing in the world like for watching the television, for working on the personal computer. As the use of computer and internet is increasing the demand for the display devices is also increasing. References Furr, Rich. (2003). Electronic Displays: The Calculator Reference. Retrieved on 7th January 2012 from http://www.vcalc.net/display2.htm Matsumoto, Shoichi. (1990). Electronic Display Devices. John Wiley and Sons Sheer, Sol. (1993). Electronic Displays. New York: John Wiley and sons. Whitaker, Jerry C. (1994). Electronic Displays: Technology, Design and Application. New York: McGraw- Hill. Read More