Light emitting diode description detail.pptx

led description

1. Topic we will discuss Introduction What is LED Display?. Principle of LED. Construction and Working. Types of LED Display. Advantages of LED Display. Application of LED Display .

2. Introduction LED (Light-Emitting Diode) The light emitting diode (LED) emits light and play an important role of opto-electronics. Light emitting diode is a special type of semiconductor PN junction diode the under forward condition can emits external spontaneous radiation in Visible and Invisible. Led is a semiconductor device that emits light when an electric current flows through it LED allowed to flow current in a forward direction and block the current in the reverse direction. Symbol :-

3. What is LED Display? An LED Display is a flat panel display. which uses and array of light emitting diodes as for a video display. their brightness allow them to be used outdoors where they are visible in the sun store sign and billboards and in recent year. They are have also become commonly used in destination sign on public transport vehicles as well as variable- message Sign Highways. “LED based on principle of electroluminescence and LED-Display based on principle of LED”. An LED Display consists of many closely-spaced LED’s. By varying the brightness of each LED, the diodes jointly from an image on the display to create a bright Colour image. Principle of LED A Junction diode such a LED can emits light or exhibit electroluminescence. energy has required to take a transition of electron from the conduction band to valence band, which is make possible by emission of photon. thus emitted light come from the hole-electron recombination required is that electrons should make a transition from higher energy to lower energy level releasing Photon.

4. Construction and Working LED is basically format by P-type and N-type semiconductor materials in N-type majority charge carriers are electrons and in P-type majority recharge careers are Hole. LED’s are not fabricate using Silicon and Germanium because in these type of diodes recombination energy is emitted in the form of the heat. Instead of that we use GaAs, Ga-P, Ga-As-P. this type of materials energy emits in the form of light. This are the basic materials are used at the time of LED fabrication. LED works on the principle electroluminescence. So convert electrical energy into light energy. Let us considered the case of P-N junction. Now a forward bias current flow due to free electron.

5. we know that the electron on N-type are in higher conduction band and whole in P-type are in lower Valance band recombination to access electron and whole take place when current is passed through P-N junction when an electron recombination with a free hole it falls from higher energy to lower energy level releasing a Photon. Characteristics of some LED materials:- Material Dopant colour Ga-As Ga-As Ga-P Ga-P Zn Si N Zn,O Infrared Infrared Green Red

6. Types of LED Display Direct LED Displays : Direct LED (also known as Direct-Lit LED) is a type of LED backlighting used in LCD displays. In Direct LED displays, LEDs are placed directly behind the LCD panel. This is in contrast to Edge-Lit LED displays, where LEDs are positioned along the edges of the screen. OLED Displays : Organic Light-Emitting Diode (OLED). Unlike traditional LEDs, OLED displays use organic compounds that emit light when an electric current passes through them. This allows for incredibly thin panels, high contrast ratios, and better color accuracy. OLEDs are often used in high-end TVs and smartphones. MicroLED Displays : Each pixel in a MicroLED display is an individual micro-sized LED. This technology offers high brightness, excellent contrast ratios, and long lifespan, and is used in premium TVs and large displays. Edge-Lit LED: In Edge-Lit LED displays, LEDs are placed around the edges of the screen. The light from these LEDs is then spread across the display using a light guide panel (LGP), which helps to distribute the illumination evenly across the screen. SMD : LEDs are tiny light-emitting diodes that are mounted on the surface of a printed circuit board (PCB). Unlike traditional LEDs, which might have leads that go through the PCB, SMD LEDs are soldered directly onto the surface, which allows for more compact and efficient designs.

7. Advantages of LED Display LED displays offer a variety of advantages over traditional display technologies such as LCD and CRT. 1. High Brightness and Visibility: Brightness: LEDs can achieve very high brightness levels, making them ideal for use in both indoor and outdoor environments where visibility is critical. Daylight Visibility: Particularly useful for outdoor digital signage and billboards, where bright sunlight can make other displays hard to read. 2. Energy Efficiency: Lower Power Consumption: LEDs are more energy-efficient compared to traditional lighting technologies. They consume less power, which can lead to significant energy savings, especially in large displays. 3. Thin and Lightweight: Slim Design: LED displays are typically thinner and lighter than other types of displays, such as CRTs or even some LCDs. This allows for more flexible installation options and can contribute to a sleeker overall design. 4. Long Lifespan: Durability: LEDs have a longer operational life compared to traditional bulbs. They can last up to 50,000 hours or more, reducing the need for frequent replacements. 5. Excellent Color Quality: High Color Accuracy: LEDs provide vibrant colors and a wide color gamut, which enhances the visual experience. This makes them suitable for applications where color precision is crucial, such as graphic design or media production.

8. 6. High Contrast Ratio: Deep Blacks: LED displays, especially OLED and MicroLED types, offer excellent contrast ratios with deep blacks and bright whites, enhancing image quality and detail. 7. Fast Response Time: Smooth Motion: LED displays generally have faster response times compared to traditional displays, reducing motion blur and making them ideal for fast-moving content, such as video games and sports broadcasts. 8. Low Heat Emission: Cool Operation: LEDs generate less heat compared to traditional lighting technologies. This can help reduce cooling costs and improve the overall efficiency of the system. 9. Flexibility and Versatility: Varied Form Factors: LEDs can be used in a range of applications, from flexible LED strips and transparent displays to large outdoor billboards and high-definition televisions. This versatility allows for creative and innovative display solutions. 10. Eco-Friendly: No Toxic Materials: LEDs do not contain harmful materials like mercury, which is found in some other types of lighting, such as fluorescent bulbs. This makes them a more environmentally friendly option. 11. Low Maintenance: Reduced Maintenance Costs: Due to their long lifespan and durability, LED displays generally require less maintenance compared to other display technologies, which can result in lower long-term operational costs.

9. Application of LED Display 1. Consumer Electronics: Televisions: LED TVs, including Edge-Lit, Direct-Lit, and OLED models, are popular for their superior picture quality, brightness, and slim design. Monitors: Used in computer monitors and professional displays for tasks requiring high resolution and color accuracy. Smartphones and Tablets: Displays in smartphones and tablets use LED technology, often OLED, for vibrant colors and high contrast. 2. Digital Signage: Retail: LED displays are used for in-store advertising, promotions, and interactive kiosks, attracting customer attention with vibrant and dynamic content. Transportation Hubs: Airports, train stations, and bus terminals use LED displays for information boards, schedules, and advertising. Event Venues: Large LED screens are used in stadiums, concert halls, and theaters for live broadcasts and event information. 3. Outdoor Advertising: Billboards: High-brightness LED billboards are used for outdoor advertising, providing dynamic and eye-catching advertisements visible in various lighting conditions. Building Facades: LED displays on building exteriors can showcase advertisements or artistic displays, enhancing urban environments.

10. 4. Automotive: Dashboard Displays: LED displays are used in car dashboards for speedometers, fuel gauges, and infotainment systems. Rear-View Mirrors: Some vehicles incorporate LED displays in rear-view mirrors for additional information and safety features. 5. Control Rooms and Broadcast Studios: Video Walls: LED video walls are used in control rooms for monitoring, in broadcast studios for news and live television, and in command centers for situational awareness. Monitoring Systems: Large, high-resolution LED screens are used for data visualization and real-time monitoring. 6. Healthcare: Medical Imaging: LED displays are used in medical imaging systems for diagnostic purposes, providing high resolution and accurate color reproduction. Hospital Signage: Informational and directional signage within hospitals and medical facilities often uses LED technology for clarity and reliability.

11. 7. Entertainment: Theaters and Concerts: LED screens are used for backdrops, visual effects, and live feeds in entertainment venues. Theme Parks: Interactive LED displays and signage are used for attractions, rides, and immersive experiences. 8. Education: Interactive Whiteboards: LED displays are used in smart boards and interactive whiteboards for educational purposes, enhancing teaching and learning experiences. Classroom Displays: High-resolution LED screens are used for presentations and educational content.