UNDERSTUDY OF THE LATEST TECHNOLOGY IN L.E.D VISUAL DISPLAY

UNDERSTUDY OF THE LATEST TECHNOLOGY IN L.E.D VISUAL DISPLAY

CHAPTER ONE

1.        INTRODUCTION

         L.E.D which is known as Light Emitting Diode was discovered More than 100 years ago in 1907, an Englishman named Henry Joseph Round discovered that inorganic materials could light up when an electric current flowed through it. 

1.1   Background of the study

The first light-emitting diode (LED) had now been born. At that time, the material properties were poorly controlled, and the emission process was not well understood. The light-emitting active material was SiC crystallites as used for sandpaper abrasive.  In the next decades, Russian physicist Oleg Lossew and French physicist Georges Destriau studied this phenomenon in great detail and the term ‘electro-luminescence’ was invented to describe this. In 1962, inorganic materials (Gasp) emitting red light were first demonstrated by Holon yak and Bevacqua at General Electric’s Solid-State Device Research Laboratory in

Syracuse, New York, although the light emitted was so weak that it could only be seen in darkened room (by comparison, the efficacy of Thomas Edison’s first incandescent light bulb was 10 times greater). Since then, the efficiency of Gap and Gasp advanced significantly in the 1960s and 1970s. The Aligned system was developed later, in the 1980s, and is now the basis of most high-efficiency LEDs emitting in the red-to-yellow visible region. The development of the nitride material system (GaN, InN, AlN and their alloys) in the last two decades has enabled efficient light emission to expand into the blue and green spectral region, and most importantly, allowing the production of white light (blue is the high-energy end of the visible spectrum and therefore enables the production of white light using blue light plus phosphors). Blue LEDs were made possible by a series of key breakthroughs in materials science. In particular, the first bright blue LED was announced at a press conference on November 12, 1993 by Nakamura [2]. The invention of efficient blue LEDs has enabled white light source for illumination. In 1997, white light was demonstrated for the first time by combining a blue gallium nitride (GaN) LED with a yellow-emitting phosphor [3]. Such LEDs are called ‘white LEDs’ Nowadays, solid-state lighting based on LEDs is already commercialized and widely used, for example, as traffic signals, large outdoor displays, interior and exterior lighting in aircraft, cars and buses, as bulbs in flash lights and as backlighting for cell phones and liquid-crystal displays. With the continuous improvement in performance and cost reduction in the last decades, solid-state For over 30 years, LEDs have been used in various areas of application weather for industrial systems, hi-fi equipment, car lights or advertising. LED technical development continues to stride ahead. In the course of recent years, the white LEDs' luminous efficacy has increased to a startling 130 lumens per watt and more. This is a trend that will continue into the future. In addition, the physical effect of electroluminescence was discovered more than 100 years ago.

          Also, LED visual display is all about an array of electric component (LED) that emits light when connected to an electric current. It is a semiconductor device that emits visible light when electric current passes through it.

The latest technology in led visual display increase productivity and to educate and entertain customers and there are several exciting new technologies coming down the pike for 2017.

L.E.D (light emitting diode) is an electric component that emits light when connected to a direct current. It is a semiconductor device that emits visible light when electric current passes through it. Output of a led varies; the output range of a light (red) is about 700 nanometers, blue light range is about 400 nanometers while some ranges to about 830 nanometers or longer. This types are called infrared emitting diode. The light emitting diode consist of semiconductors which are known as the P-type conductor and N-type conductor.

LED display is a flat panel display, which uses an array of light-emitting diodes as pixels for a video display. Their brightness allows them to be used outdoors where they are visible in the sun for store signs and billboards, and in recent years they have also become commonly used in destination signs on public transport vehicles, as well as variable-message signs on highways. LED displays are capable of providing general illumination in addition to visual display, as when used for stage lighting or other decorative (as opposed to informational) purposes.

A light-emitting diode (LED) is a two-lead semiconductor light source. It is a p–n junction diode that emits light when activated.[5] When a suitable current is applied to the leads,[6][7] electrons are able to recombine with electron holes within the device, releasing energy in the form of photons. This effect is called electroluminescence, and the color of the light (corresponding to the energy of the photon) is determined by the energy band gap of the semiconductors

Flat-panel displays are electronic viewing technologies used to enable people to see content (still images, moving images, text, or other visual material) in a range of entertainment, consumer electronics, personal computer, and mobile devices, and many types of medical, transportation and industrial equipment. They are far lighter and thinner than traditional cathode ray tube (CRT) television sets and video displays and are usually less than 10 centimetres (3.9 in) thick. Flat-panel displays can be divided into two display device categories: volatile and static. Volatile displays require that pixels be periodically electronically refreshed to retain their state (e.g., liquid-crystal displays (LCD). A volatile display only shows an image when it has battery or AC mains power. Static flat-panel displays rely on materials whose color states are bistable (e.g., e-book reader tablets from Sony), and as such, flat-panel displays retain the text or images on the screen even when the power is off. As of 2016, flat-panel displays have almost completely replaced old CRT displays. In many 2010-era applications, specifically small portable devices such as laptops, mobile phones, smartphones, digital cameras, camcorders, point-and-shoot cameras, and pocket video cameras, any display disadvantages of flat-panels (as compared with CRTs) are made up for portability advantages (thinness and lightweightness).

Most 2010s-era flat-panel displays use LCD and/or LED technologies. Most LCD screens are back-lit as color filters are used to display colors. Flat-panel displays are thin and lightweight and provide better linearity and they are capable of higher resolution than typical consumer-grade TVs from earlier eras. The highest resolution for consumer-grade CRT televisions was 1080i; in contrast, many flat-panels can display 1080p or even 4K resolution. As of 2016, some devices that use flat-panels, such as tablet computers, smartphones and, less commonly, laptops, use touchscreens, a feature that enables users to select onscreen icons or trigger actions (e.g., playing a digital video) by touching the screen. Many touchscreen-enabled devices can display a virtual QWERTY or numeric keyboard on the screen, to enable the user to type words or Numbers.

  1.2   STATEMENT OF THE PROBLEM

   In the world today, communication and data accessing as made life easier in getting access to data and Internet but still a large number of people in places around the country and the world don't have access to internet. Information can be gotten at any means through phones or computers even little gadget. But the latest technology in data accessing and transfer of data is with the aid of LED light which is called LIFI known as LIGHT FIDELITY. It is a technology for wireless communication between devices using light to transmit data and also position. This can only be done using LED lamps. The speed of this LIFI is about 70mb/s If only reflected by a wall, which means it can also transmit at a higher speed.

     In schools, passing of information can be hectic when it comes to posting/pasting of papers on noticeboards around faculties and department and which some student do not usually notice the message being passed or distributed to the school but the use of electrical powered coloured displays notice board will attract student and also staff's  to the notice board and aid in the release of result which will reduce and elimate issues of result posted being torn by student or destroyed by rain or water.

       Although including digital displays involves an initial investment, LED displays in schools ultimately reduce overall costs. Displaying marketing information, educational resources, and classroom notes on our digital screens will save money by reducing the use of paper and printing.Since our everyday life is heavily impacted by technology, involving digital displays in the education sector will enhance their overall learning experience. Digital signs help in increasing the level of technology in educational center and create a lasting first impression with students and parents. video screens made of led in classrooms enhancing practical and theorical teachings,  led video screen allows schools to captivate guests by displaying achievements and exceptional work completed by students and staff.

     Most hospitals require a certain standard of lighting to not only provide the best care for their patients, but to provide a comfortable environment for both employees and patients. Surgeons, for example, require a high quality light, of the right color temperature and output, that doesn’t produce glare or shadows. Lights that do not generate heat are also important for both the comfort of the surgeon and the safety of the patient (high heat can dry out tissue) LED lighting is the only available solution to this issues.

      Not only do LEDs meet all these requirements, but the ability to dim is extremely useful in certain applications, such as MRI (Magnetic Resonance Imagery) rooms.  This is a diagnostic technique that uses magnetic fields and radio waves to produce a detailed image of a body's soft tissue and bones. Dimming also provides a more soothing environment for patients. Other reasons in the hospitals are;

Creating conducive environment for patients

      Lighting plays an important role in healthcare, improving both the patient experience and the staff’s ability to provide the required level of care. Not only a sustainable choice, LED lighting can enhance the care environment and reduce costs by saving energy and improving operational efficiency. The latest LED technology provides a nurturing atmosphere for patients and a dynamic working environment for staffs.

Ultrasound and CT scan rooms

      Besides the characteristics mentioned above LED tubes and bulbs are dimmable making them ideal for CT scan and ultrasound rooms where dimming may be needed for better observation and patient comfort. Since these lights power on and achieve full brightness instantly a hospital may even choose non-dimmable lights. To lower light levels, some of the lights can be switched off instead of using a dimmer circuit.

Enhance comfort

        use  ambient lighting to relax and reassure patients Attract and retain valuable staff through a pleasant working environment Create a relaxing and welcoming environment in reception, examination, and patient rooms Improve experience Simulate natural daylight to support patients' sleep, mood, and recovery also create  a pleasant ambience for patients and visitors enhance  the well-beingand concentration of facility staff.

The objectivies of this project are:

·        To introduce and interpolate the existence of LIFI with more clerical fact and information.

·        This project breaksdown the effect and simplicity of LIFI with the aid of LED ( Light emmiting diode)

·        To know and understand the technology of led displays applied in hospitals.

·        To understand the usefulness and application of a LED bulbs and LED visual displays in hospitals.

·        Shows or gives detailed on how LED VISUAL DISPLAY enhances teaching in the education sector.

·        Increase in effective communication to student and staffs of tertiary institution with the use of led visual display.

·        To show the evolution of Led for more than hundred years to what it is today.

1.3       CONTRIBUTION TO KNOWLEDGE

The contribution of knowledge to this project is that LED VISUAL DISPLAY will be beneficiary to Hospitals in enhancing health care and providing adequate comfort to both hospitals staff and patients and the reduction of the amount of money or tax payed on electricity bills which enables the hospital focus more on the cost of patient than electricity bills. And also increase equipment that are using light emmiting diode (LED) which are healthy to the  patient. Also aid in passing information adequately in schools through the use of led visual display notice board  powered by electricity. Also how the use of new source of access to data can educate people or become known to the economy.

  

     1.4       LIMITATION/SCOPE OF THE PROJECT

The limitation of this project is that, The knowledge obtained from this research might not be adhered or accepted or considered because most of the hospitals in our locality have been built and so reconsructing the electrical system or plan of an already built hospital/care center might or will result to increase in budget or  money to be spent on reconstruction/renovation of the hospital buildngs. Schools also might find it difficult to adapt to using electrical powered notice board because of it years of using papers to show result to student. The use of led would be ineffective because of the lack of maintenance culture in some schools and management.

1.5  DEFINATION OF TERMS

Led- A light emitting diode, it has only two legs which is the cathode and anode.

LIFi - Light Fidelity

CFL - Compact Florescent bulb

MRI - Magnetic Resonance Imaging

The cathode is the negative while the anode is positive. A led has different colours such as, white, green, blue and yellow.

A visual display, informally a screen, is a display device for presentation of images, text, or video transmitted electronically, without producing a permanent record. Electronic visual displays include television sets, computer monitors, and digital signage. They are also ubiquitous in mobile computing applications like tablet computers, smartphones, and information appliances.

A liquid-crystal display (LCD) is different from Led, therefore, an Lcd is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals. Liquid crystals do not emit light directly, instead using a backlight or reflector to produce images in color or monochrome.[1] LCDs are available to display arbitrary images (as in a general-purpose computer display) or fixed images with low information content, which can be displayed or hidden, such as preset words, digits, and seven-segment displays, as in a digital clock.