Flat panel display

This presentation is describing what is flat panel display and its type, advantages and disadvantages and difference between crt and fpd

1. Flat Panel Display Submitted by: 1.Manohar Bhasin 2.Rishi Singh 3.Sandeep Kumar Singh Submitted to: Prof. Satish Bansal

2. Introduction Types of flat panel displays Applications of flat panel displays Advantages of flat panel displays and disadvantages of flat panel display Difference between flat panel displays and crt CONTENTS

3. INTRODUCTION FPD refers to class of video devices that have reduced volume,weight,and power requirement compare to a CRT. The first ever flat panel display was invented in 1964 at the university of illinois . Flat panel displays also called flat screen. It encompass a growing number of electronic visual display technologies. It enables much lighter and thinner than traditional television set and video displays that use cathode ray tubes ( crt ). These are usually less than 100 mm (4 inches) thick.

4. Types of flat panel displays Emissive:- The emissive display are devices that convert electrical energy into light. Plasma display panel (PDP) Thin- flim electroluminescent display Light emitting diode (LED) display Non-Emissive:- The non-emissive display use optical effect to convert sunlight or light from some other source into graphics patterns. Liquid crystal display (LCD)

5. Plasma panels also called gas-discharge display PDP are constructed by filling the region between two glass plates with of glass that usually include neon. Picture definition is stored in a refresh buffer. Their visual displays are comparable to cathode ray tubes, but can be built much thinner and flatter. These are not suitable for portable and handheld devices. Plasma display panel Glass plate Vertical grid conductor cells Vertical grid conductor Glass plate

6. It is similar in construction to a plasma panel. The region between the glass plates is filled with a phosphor, such as zinc sulfide doped with manganese, instead of a gas. Electroluminescent displays require more power than plasma panels and good color and grey scale display are hard to achieve. THIN-FLIM ELECTROLUMINESCENT DISPLAY

7. Light emitting diode (LED) display It is third type of emissive device. A matrix of diodes is arrange to form the pixel position in the display. Picture definition stored in refresh buffer. These used for large, outdoor screens and billboards. Each pixel is formed using a cluster of red, green and blue LEDs.

8. Liquid crystal display It is a non-emissive devices produce a picture by passing polarized light from the surrounding or from an internal light source through a ‘liquid- crystal’ material that can be aligned to either block or transmit the light. In an LCD , the pixels are switched on or off electronically using  liquid crystals  to rotate  polarized light . LCDs are commonly used in small systems, such as calculator and portable, laptop computers.

9. How pixels are switched off/on in LCDs Light travels from the back of the TV toward the front from a large bright light. A horizontal polarizing filter in front of the light blocks out all light waves except those vibrating horizontally. Only light waves vibrating horizontally can get through. A transistor switches off this pixel by switching  on/off  the electricity flowing through its liquid crystals. That makes the crystals straighten out (so they're completely untwisted)/twisted, and the light travels straight through them unchanged/ The twisted crystals rotate light waves by 90° as they travel through.. Light waves emerge from the liquid crystals still vibrating horizontally. A vertical polarizing filter in front of the liquid crystals blocks out all light waves except those vibrating vertically. The horizontally/vertically vibrating light that travelled through the liquid crystals cannot get through the vertical filter. No light reaches the screen at this point. In other words, this pixel is dark.

10. Cont..

11. Applications of flat panel displays Laptops Televisions Cellular phones Digital cameras Camcorders Compact cameras Pocket video camera

12. Advantage and Disadvantage ADVANTAGE Sharpness: Image is perfectly sharp at the native resolution of the panel. Geometric distortion: Zero geometric distortion at the native resolution of the panel. Minor distortion for other resolutions because the images must be rescaled. High levels of brightness: High peak intensity produces very bright images. Best for brightly lit environments. Unique screen shape: Screens are perfectly flat. Less consumption of electricity: Thin with a small footprint. Consume little electricity and produce little heat. DISADVANTAGE Resolution Each panel has a fixed pixel resolution format determined at the time of manufacture that can not be changed. All other image resolutions require rescaling, which generally results in significant image degradation, particularly for fine text and graphics. For most applications should only be used at the native resolution of the panel.

13. Difference b/w CRT and FPD Basis for comparison CRT FPD Major components Vacuum glass tube, phosphor screen, electron gun, deflection plates. Glass plates, nematic liquid crystal, internal light source. Size CRT is weighted, bulky and large in size. FPD is light, compact and thin in size. Weight is lighter Power consumption It consumes high power. It consumes low power. Image flickering Image flickering is there in CRT. No image flickering is there in LCD. Cost It is less expensive. It is more expensive.

14. Thank you skingh