Flat Panel Display (FPD)
Definition of flat panel display (FPD):
FPD (Flat Panel Display), as the name suggests, is a flat-screen TV. It is a type of TV compared to the huge body of traditional CRT TVs. It mainly includes LCD (Liquid Crystal Display) and plasma display PDP. (Plasma Display Panel), organic electroluminescence display OLED (Organic Light EmitTIng Display), surface conduction electron emission display SED (Surface-conducTIon Electron-emitter Display) and other major technical types of TV products.
The main categories of flat panel displays (FPD):
A flat panel display is a monitor, and there are three types:
Cathode Ray Tube (CRT)
Liquid Crystal Display (LCD)
Plasma display (PDP)
CRT (cathode ray tube) flat panel display
CRT (cathode ray tube) flat panel displays can be 6 inches to 36 inches small in different sizes, and emit negatively charged electron beams through the electromagnetic field. The dots are coated on the screen with phosphors, so that the excitement is correct and you can view Image.
CRT monitors can have a large range of resolutions and palette capabilities; from 800 × 600 (11 inches) to 1024 × 768 (XGA extended graphics array) and 1280 × 1024 (super resolution XGA).
The upper-end models can even reach resolution fines of 1600 × 1200 (UXGA Ultra XGA) and 2048 × 1536 (QXGA, Quad XGA)
The main CRT technologies used are aperture grille (tension mask), shadow mask technology and mask slot technology, which uses two tension and shadow mask technologies.
The shadow mask technology makes the triangles of red, blue, and green polka dot mini black holes in the glass of the metal plate.
Aperture grill is a vertical arrangement of tiny wire diameters on the screen. The electron beam passes through this vertically arranged (grilled) and produced illuminated phosphor-coated glass plate.
The viewing area ratio of the CRT monitor is 4: 3, and the screen size (in inches) is measured by the diagonal of the screen (edge ​​to edge).
Liquid crystal display (LCD) flat panel display The liquid crystal display (LCD) polarizes light into a visible image.
When light passes through the first glass plate, the two glass plates (substrate) between the liquid crystals affect the current flow and only allow the current image of a specific light wave to pass through them the second glass plate.
In view of this it is expected that the second glass plate is the actual image you see.
The LCD has a matrix of horizontally and vertically arranged glass plates of micro-transistors and utilizes both active matrix technology and passive matrix technology.
The switches and columns in the exact rows of the active matrix are allegations, intertwined rows. The capacitor is connected to the intersection to hold its charge until it refreshes next to the screen.
In passive matrix technology, each pixel is accused of being arranged in a grid through metal conductors.
The resolution of the LCD monitor is directly related to the size of the screen. The 17-inch display can be 1024 × 768 resolution, the 19-inch display can be 1280 x 1024 resolution and the 20-inch screen can be 1600 × 1200 resolution.
However, unlike CRT monitors, LCD monitors can only accept digital signal data (including DVI format).
Plasma display (PDP)
A plasma display is a flat panel display that uses the emitted light to ionize gas to display an image.
The set of these two electrodes is arranged in a grid, and the charge applies. The charge of the display electrode is released into the ionized gas, which in turn, the released ultraviolet photons hit the phosphor-coated cell wall and release light photons.
These light photons are then projected on the screen image.
Although plasma displays are considerably more expensive than flat-panel displays; resolution-quality plasma TVs are not necessarily any better than high-end LCD or CRT displays, and in many cases, even fewer.
However, the overall brightness and visual clarity can be quite amazing, and like an LCD flat panel display, plasma displays only accept digital TV signals.
The development trend of flat panel display (FPD)
Compared with the traditional CRT (cathode ray tube), the flat panel display has the advantages of thinness, light weight, low power consumption, low radiation, no flicker, and is beneficial to human health. At present, it has surpassed CRT in terms of global sales. It is estimated that by 2010, the ratio of the two sales value will reach 5: 1. In the 21st century, flat panel displays will become the mainstream products in the display. According to the prediction of the famous Stanford Resources company, the global flat panel display market will increase from 23 billion US dollars in 2001 to 58.7 billion US dollars in 2006. The average annual growth rate in the next 4 years will reach 20%.
Each has its own flat panel display technology
Flat panel displays are divided into active light-emitting displays and passive light-emitting displays. The former refers to the display device that the display medium itself emits light to provide visible radiation. It includes a plasma display (PDP), a vacuum fluorescent display (VFD), a field emission display (FED), an electroluminescence display (LED), and an organic light-emitting diode display (OLED )Wait. The latter refers to the fact that it does not emit light itself, but its optical characteristics are changed after being modulated by an electrical signal using a display medium, modulating the ambient light and the light emitted by an external power source (backlight source, projection light source) on a display screen or screen Display devices include liquid crystal displays (LCD), micro-electromechanical system displays (DMD) and electronic ink (EL) displays.
1. Liquid Crystal Display (LCD)
Liquid crystal displays include passive matrix liquid crystal displays (PM-LCD) and active matrix liquid crystal displays (AM-LCD). Both STN and TN liquid crystal displays are passive matrix liquid crystal displays. In the 1990s, the active matrix liquid crystal display technology has achieved rapid development, especially the thin film transistor liquid crystal display (TFT-LCD). As a replacement product of STN, it has the advantages of fast response and no flicker. It is widely used in portable computers and workstations, TVs, video recorders and handheld video game consoles. The difference between AM-LCD and PM-LCD is that the former has a switching device added to each pixel, which can overcome cross-interference and can obtain high contrast and high resolution display. The current AM-LCD uses an amorphous silicon (a-Si) TFT switching device and storage capacitor scheme, which can obtain high gray levels and achieve true color display. However, the demand for high resolution and small pixels in high-density cameras and projection applications has driven the development of P-Si (polysilicon) TFT (thin film transistor) displays. The mobility of P-Si is 8 to 9 times higher than that of a-Si. The small size of the P-Si TFT is not only suitable for high-density and high-resolution display, but also peripheral circuits can be integrated on the substrate.
All in all, LCD is suitable for thin, light, and small and medium-sized displays with low power consumption. It is widely used in electronic devices such as notebook computers and mobile phones. 30-inch and 40-inch LCDs have been successfully developed, and some have been put into use. After large-scale production of LCD, the cost is continuously decreasing. Currently, a 15-inch LCD monitor with a market price of $ 500 is available. Its future development direction is to replace the cathode display of PC and apply in LCD TV.
2. Plasma display (PDP)
Plasma display is a light-emitting display technology using the principle of gas (such as atmospheric gas) discharge. Plasma displays have the advantages of cathode ray tubes, but they are manufactured on very thin structures. Currently, the mainstream product size is 40 42 inches. 50 60 inch products are under development.
3. Vacuum fluorescent display (VFD)
Vacuum fluorescent display is a display widely used as audio / video products and household appliances. It is a kind of triode electron tube type vacuum display device which encapsulates the cathode, grid and anode in the vacuum tube shell. It is that the electrons emitted by the cathode are accelerated by the positive voltage applied by the grid and anode, and excite the phosphor coated on the anode to emit light. The grid uses a honeycomb structure.
4. Electroluminescence display (ELD)
Electroluminescent displays are made using solid-state thin-film technology. An insulating layer is placed between the two conductive plates, and a thin electroluminescent layer is deposited. The device uses a wide-emission spectrum zinc-coated plate or strontium-coated plate as an electroluminescent component. The electroluminescent layer is 100 microns thick, which can achieve a clear display effect like an organic light emitting diode (OLED) display. Its typical driving voltage is 10KHz, 200V AC voltage, so it requires a more expensive driver integrated circuit. High-resolution microdisplays using active array drive schemes have been successfully developed.
5. Light-emitting diode display (LED)
The light-emitting diode display is composed of a large number of light-emitting diodes, which can be monochrome or multi-color. High-efficiency blue light-emitting diodes are available, making it possible to produce full-color large-screen light-emitting diode displays. The LED display has the characteristics of high brightness, high efficiency and long life, and is suitable for a large screen display for outdoor use. However, this technology cannot be used to manufacture medium monitors for monitors or PDAs (handheld computers). However, the LED monolithic integrated circuit can be used as a monochrome virtual display.
6. Micro Electro Mechanical System Display (DMD)
This is a micro-display manufactured using MEMS technology. In this type of display, the miniature mechanical structure is manufactured using standard semiconductor processes to process semiconductors and other materials. In the digital micromirror device, its structure is a micromirror supported by a hinge. Its hinge is excited by the charge connected to the polar plate of a memory cell below. The size of each micromirror is approximately the diameter of a human hair. The device is mainly used for portable commercial projectors and home theater projectors.
7. Field emission display (FED)
The basic principle of the field emission display is the same as that of the cathode ray tube, that is, the polar plate attracts electrons and makes it collide with the phosphor coated on the anode to emit light. Its cathode is formed by a large number of fine electron sources arranged in an array, that is, arranged in an array of one pixel and one cathode. Just like the plasma display, the field emission display requires high voltage to work, and its voltage range is 200V to 6000V. But so far, due to the high production cost of its manufacturing equipment, it has not become a mainstream flat panel display.
8. Organic light-emitting diode display
In an organic light-emitting diode display (OLED), when a current passes through one or more layers of plastic, a phenomenon similar to that of an inorganic light-emitting diode will occur. This means that what the OLED device needs is a solid film stack on the substrate. However, organic materials are very sensitive to water vapor and oxygen, so sealing is essential. OLED is an active light-emitting device, and shows excellent light characteristics and low power consumption characteristics. They have great potential for mass production on a flexible substrate in a roll-to-roll process, so their manufacturing costs are very low. The technology has a wide range of applications, from simple monochromatic large-area lighting to full-color video graphics displays.
9. Electronic ink display (E-ink)
The E-ink display is a display controlled by applying an electric field to a bistable material. It consists of a large number of micro-sealed transparent spheres, each sphere is about 100 microns in diameter, and contains black liquid dye material and thousands of white titanium dioxide particles. When an electric field is applied to a bistable material, the titanium dioxide particles will migrate to one of the electrodes according to their charge state. This causes pixels to emit light or not. Because this material is bistable, it can retain information for several months. Because its working state is controlled by an electric field, the content displayed can be changed with very little energy.
LCD, PDP and OLED
Each technology for manufacturing flat panel displays has its own advantages and disadvantages (see Table 1). However, LCD will still dominate the future flat panel display market. In the next few years, the market share of LCD, which currently accounts for 90% of the flat panel display market, will gradually decrease. However, as a general-purpose display, it is none other than it. In addition, the development prospects of LCD and OLED are also very promising. These three will occupy a dominant position in the future flat panel display market
Variable Frequency AC Power Supply
Variable Ac Power Supply,Variable Frequency Power Supply,Ac Power Supply Variable Voltage,Ac Power Supply With Variable Frequency
Yangzhou IdealTek Electronics Co., Ltd. , https://www.idealtekpower.com