DISPLAYING

1. DISPLAYING By Adam, Elle, Justin, Grant, Kade

2. Hardware for Displaying ‘There is a number of technologies available in the IT world for displaying information, including various types of monitors, printers, speakers, data projectors and plotters.’ You will learn: • Learn how display hardware works • Discover the distinction between dynamic and static displays

3. Cathode Ray Tubes (CRTs) • The CRT is oldest and most familiar of the VDU devices. Most older TVs are still based off CRT technology. Problems with CRT technology: • Its bulky and heavy • It uses a lot more electricity than LCD technology • It has an ‘annoying flicker’ when it refreshes - this is noticeable when you take a picture of a CRT monitor/tv. Advantages with CRT technology: • It is cheap to manufacture • Produces a bright, clear display that is good for gaming because it has a higher refresh rate than LCDs. • Can be viewed from a wide range of angles unlike some LCDs.

4. Liquids Crystal Displays (LCDs) These displaying devices are common in laptop and notebook computers, and are now becoming common among desktop machines. An LCD uses a material that switches between blocking light and allowing it to pass through when an electric current is applied LCDs are usually classified into two categories: passive matrix + active matrix. • Passive matrix LCDs use a grid of electrodes on both sides of the LCD layer. While this is a very simple system, it is slow and inaccurate. The current applied to a particular crystal will also affect the crystal will also affect the crystals immediately around it and cause them to twist slightly. • Active matrix LCDs give every crystal its own switches and battery. The switches improve the sharpness of an image because they stop the neighboring crystals from being affect when a crystal is ‘turned on’.

5. Advantages + disadvantages with LCD technology LCD technology has significant advantages over CRT technology. They: • Are thinner and lighter • Use less power than CRT technology (this makes them suitable for laptops) • Produces less electromagnetic radiation There are also some disadvantages with LCD technology • Limited viewing angles • Displays are not as bright • They have a lower refresh rate and therefore are not ideal for gaming.

6. Plasma displays Plasma displays have relations with fluorescent light tubes and neon-light advertising signs. The plasma screen is covered with hundreds of thousands of individual cells that receive a constant flow of low-pressure neon and xenon gas. The plasma produces invisible high- energy UV light that hits the phosphor (Substance which glows when struck by electrons. The back of a cathode ray tube face is coated with phosphor) coating inside the cell and causes it to emit its own red, green or blue light.

7. OLED (Organic Light Emitting Diode) OLED displays have relations also with certain jellyfish and bacteria. OLED is based on bioluminescence, which is the ability of some living organisms to produce their own light. Unlike other display systems, OLED displays can be built by using thin, flexible plastic that can be rolled and bent into any shape. OLD displays have a number of advantages over LCD displays: • Greater brightness - OLED displays produce their own light and do not need a backlight. • A wider viewing angle unlike some LCD displays! • They have a faster response time - this makes them better gaming. • Greater durability - they are less prone to physical damage • They are lighter, thinner and more flexible - this opens new possibilities.

8. Video Projectors There are now several different systems for projecting video images onto a screen or wall. The two most popular are: • LCD (Liquid Crystal Display) projectors, which work in the same way as an LCD screen but uses a strong light source to ‘project’ the images onto the wall. • DLP (Digital Light Processor), which creates images by controlling hundreds of thousands of microscopic mirrors mounted on single chip. The mirrors, organised in groups of three, reflect light from different coloured lamps to form the individual pixels on the screen.

9. Digital vs. Analogue Varying the voltage levels in the display devices controls the intensities of the red, green and blue primary colours in an image. Signals with varying voltage levels are analogue signals. In CRT displays, the voltage applied to each electron gun controls the intensity of the electron beams and the colour produced by each pixel. For an LCD, the voltage applied to each crystal controls the amount it produces. Even a DLP projector relies on a varying voltage signal to control the movement of each of the mirrors on the DLP chip. Computer are digital, but most VDUs (Visual Display Unit) are not digital – they rely on analogue data signals. The digital data stored in your computers video RAM (ram on the video card) are converted into three separate analogue signals (Red, Green and Blue) together with several control and timing signals. The signal passed through the cable connected to the video card, and this cable must be digital to plug into the digital video card. A DVI (Digital Video Interface) sends a digital video signal to the video display device. Digital broadcast TV uses the same broadband technology to carry the data from the TV transmitter to your home. A digital set-top box is needed to convert the data signal to digital to digital if your TV is not yet digital.

10. Inkjet printers Inkjet printers fire microscopic drops of ink at the paper. This is achieved in two ways: • Electric charges – the ink entering the nozzle is given a small electric charge; it is then repelled out of the nozzle by a stronger charge of the same type • Heating – an electric wire is used to heat a small pocket of air behind the ink in the nozzle; the heated air forms an expanding bubble that forces the ink out. These types of printers are sometimes referred to as ‘bubble jet’. The quality of inkjet printing depends a great deal on the quality of the paper. Gloss paper improves the quality of the image. Standard paper has a rougher, slightly uneven surface and this scatters the reflected light straight back and makes the image look brighter. The glossy surface reduces the ink absorption, and therefore produces sharper, clearer images. Inkjet printers have become the most popular home printers because of their low purchase cost and their ability to produce good quality colour graphics. Printer manufactures loose money when they sell printer hardware, and regain that money from charging through the roof on ink cartridges.

11. Laser Printers • A laser printer uses a similar process to a photocopier to produce high quality output. It uses a laser beam to place dots onto a light sensitive drum. The drum is rotated slightly and another line of dots is added. The exposed part of the drum is given an electric charge in those places where the laser has hit it. As the drum continues to rotate, these charged areas attract fine particles of a black powder called toner. • A number of different laser mechanisms exist, with many of the lower priced printers using a row of light emitting diodes instead of a single laser beam to create each row of dots on the drum. Colour laser printing usually involves the paper being pressed onto the drum several times, with a different coloured toner added on each pass. This makes the printing slower and the cost of the more complicated print mechanism ad coloured toners make it much more expensive.

12. Plotters • Plotter draw lines on paper using one or more ink pens, to create the drawing. Ina flat-bed plotter the paper is laid flat on a surface similar to a drafting table and a pen moves over the paper to create the drawing. The computer I controlled by the computer moving a bar left and right across the paper controls the operation. • In a drum plotter, the paper is rolled on a drum and a pen suspended above the drum draws the image as the drum rotates back and forth. • Plotters are commonly used to create engineering drawings, although large format laser printers that can take A3 size paper and larger are now taking over this role.

13. Software for Displaying You will learn: • About the role of software in the display process • How data can be shared to improve the display of information

14. The user interface • Laser printers and photocopiers use identical technology, so it is not surprising that the new breed of digital photocopiers can be directly connected to the computer network to act as a high-speed laser printer. This gives the computer users access to print layout features that are normally found only in expensive high-volume office photocopiers.

15. The user interface • The presence of an advanced graphics adaptor display card in the system adds additional controls to the interface. The controls in the user display interface allows users to set and altar: • The screen resolution • The number of display colours • The placement of hyperlinks directly onto the desktop screen • Division of the screen display between serval separate VDU’s

16. Dynamic Data Exchange • Users often need to share data between different software applications, such as a chart from a spread sheet that is needed in a word processed report. The most common way of this data being shared is through clipboard. However, this has a disadvantage that the user has to manually switch from one application to another and copy and paste. Every time the data is updated, the user must repeat the process to paste the updated into the document each time you want to change it. Another way is to set up a dynamic data link between documents. Once this link has been established there is no need for any further coy and pasting whenever the original data are updated.

17. Dynamic Data Exchange • With a dynamic link in he place between different documents, any changes made to this data in the source document are also made to the data in the linked documents. This is possible because whenever a document containing dynamically linked data is opened, the following steps are automatically performed: • The linked data in the loaded document are detected by the application software • The source document, which is identified by data stored in the link, is located and opened. • The linked data are found and copied from the source document • The linked data are formatted and placed into the destination document.

18. Mail Merge • Mail merge is a very convenient way for businesses or organizations with large mailing lists of customers to handle mass mail-outs. It merges data from tow different documents – a database of names and addresses with a word-processed letter.

19. Presentation Software • Presentation software applications are used to create the digital slide shows that are common at conferences and business presentations. They allow a user to combine data from a variety of documents and data files to create a series of graphic images, animations, video clips, audio clips and links to web pages. Fades or transitions between different slides and within a slide are easily created.

20. Presentation Software • The technology gives the presenter all of the advantages of an interactive computer-controlled environment to present their message in a way that is clear. The media can easily take over the presentation so that the original message is lost amongst all the glitter. Often, the presentation will be more effective without all of the technology used. Some organizations have banned their employees from using presentation software because of the time spent in preparing a presentation.

21. Display Application • There are many software applications that provide special display features and options for users who need to control how information is presented. Some of the features allow the users to make adjustments t the display format and to automatically keep shared data up to date.

22. Charts • A chart can be a very useful displaying tool. In chapter 5 we discovered that one of these charts can replace a large and confusing table of data and show the same data in the form that can show relationships, trends and comparisons at a glance. The only difficulty in these charts is choosing the display format that best shows the relationships, trends and comparisons.

23. Object linking • The disadvantages of a dynamic data link are that you must reload the original document using its original application program to update the information. An object avoids this by letting you be able to fully edit the original data, with all tools that were used to create it. • When you activate a linked object inside a document, software application identifies the application program that created the original data. Your current application loads the tools and menu commands from the original application program. Control of the data in the linked object is given to those tools and commands. The rest of your current document is still under the control of your current application program and ill not being affected. This allows you to edit the linked data using the tools that were originally used to create it. So a formulae inside a spreadsheet cell, for example can be directly edited in the word-processed document where it has been pasted. However any alteration you make will not change the original data in the source document, hey will only affect the linked data you see in the destination document. Both applications programs must be capable of using this feature, usually called ‘object linking and embedding’ or OLE.

24. Non-computer-based tools You will learn: • See how modern display systems are still based on pre-computer display systems • Discover how old and new display technologies are being merged

25. Types of Display • Text, image and audio data were commonly displayed long before the arrival of computer technology. Images have been created since before recorded history. Terms such as ‘typeface’, ‘font’, ‘point size’ and others that describe text have been in use for four centuries.

26. Display Methods • Some of the display methods and many of the terms used in the display of data on computer based information systems have come directly from pre-computer display technologies. For example, the term ‘cel animation’ is still used today with computer-generated animations, but comes from the traditional method of hand drawing and painting frames on transparent sheets.

27. Storyboard • A storyboard is a visual plan of a video, movie or animation project. It shows the story as a sequence of scenes. Despite all new display technologies that have appeared, paper is still one of the most used and versatile methods of displaying data. Electronic display systems have not yet come close to replacing a paperback book for reading in bed, or on a crowded train or bus.

28. Advantages One of the many advantages of paper is that it can be read in almost any lighting conditions and from almost any angle. This is because it relies entirely on reflected light and usually has the maximum possible contrast between the white surface and the black text. Disadvantages A big disadvantage of paper is that it is not a dynamic display system. Once a sheet has been printed it cannot be altered. To produce a book, such as this one, separate sheets of paper have to be individually printed and bound together, with a significant cost to the consumer and the environment. Advantage & Disadvantages

29. You will learn: About some of the social issues associated with displaying systems Social issues

30. Privacy & Security Communication technology allows data to be shared quickly between a large number of different information systems. At each of these systems any number of users may have access to the data. This makes it easy for private and confidential data to be accessed.

31. Access & Control Without communication systems, such as the Internet and telephone networks, there would be little or no flow of information to users. Whoever controls those systems also controls the information, they also decide on who has access to the information and how much that we shall pay. This may divide our society into two groups of the ‘Information Rich’ and the ‘Information Poor’.

32. The Changing Nature Of Work Because technology becomes updated so quickly, the people who lack skills in this area will be left behind and risk becoming unemployable. This trend will accelerate as more industries are forced to downsize their workforce and automate their manufacturing operations in an effort to compete in their global market.