Flat Panel Display
Although most graphics monitors still use CRT constructs, some other technologies may soon replace a
flat panel display (flat-paned display) on a CRT monitorrepresents a class of video devices that reduce volume, reduce weight, and conserve power compared to the CRT. A meaningful feature of a flat panel display is that it is thinner than a CRT and can be hung on a wall.or worn on the wrist. Some flat panel displays can also be written, so they can be used in pocket-sized notebooks. Flat panel displays are also used for small TV monitoringcalculators, pocket-sized video game consoles, laptops, movie screens on air seats, billboards in elevators, andas a graphical display in applications where low-demand portable monitors are required.
We can
divide the flat panel display into two categories : the
transmitter display (emissive display) and the
non-transmitting display (nonemissivedisplay). A transmitting display is a device that converts electrical energy into light energy . Plasma display panel , thin film photoelectric display and luminescence two the Pole tube is an example of a transmitter display . Flat-plate CRT has also been invented, wherein the electron beam in parallel to the direction of the screen to accelerate, butrear deflection 90 bombardment screen. However, it has not been confirmed that the flat-panel CRT can be practically applied as other transmitting devices. Non-emitting displayUse optical effects to convert sunlight or light from certain other sources into a graphical mode. The LCD device is a
non-emitting flat panel display The most important example.
Plasma display Panel (plasma panel) is also known as a gas discharge display (Gas-discharge display), which is formed by filling the area between two glass panes with a gas mixture normally containing neon gas. A series of vertical conductive bands are placed on a glass plate, and a set of horizontal conductive bands is constructed on the other glass plate (see figure 2.11). The ignition voltage is applied to the paired horizontal and vertical conductive bands, and the gas at the intersection of the two conductive bands is induced to enter the glow discharge plasma area of electrons and ions. The definition of the graph is stored in the refresh cache, where the ignition voltage refreshes the pixel position at a rate of 60 times per second (intersection of the conductive band). By using alternating current method to provide ignition voltage quickly , a brighter display can be obtained. The separation between pixels is provided by the electric field of the conductive band . The plasma display board has one drawback, namely that it is a strict monochrome device, but has now developed a plasma display that can display color and grayscale levels.
Thin Film Photoelectric display (Thin-film electroluminescent display) has a structure similar to that of a plasma display plate. of different is where it is in the area between the glass panes filled with fluorescent material, such as zinc sulfide and manganese gel, rather than gas (see Figure 2.13.), when when a high enough voltage is added to a pair of crossed electrodes, the fluorescence layer becomes a conductive body in the cross area of the two electrodes. Energy is absorbed by the manganese primitive , and then the energy is released as a luminescent highlight, similar to the plasma effect of the glow discharge of a plasma display plate. The optical display needs more power than the plasma display board, and it is difficult to achieve good color and gray level display.
the third type of transmitting device is the
light Emitting diode (light-emitting diode, LED). the diodes are arranged in a matrix to form the display Pixel location, the definition of the graphic is stored in the refresh cache . As with the scan line refresh of the CRT, information is read from the refresh cache andconverted to a voltage level and then applied to the diode to produce a glowing pattern on the monitor.
LCD Monitor (Liquid-crystal display. LCD) is typically used in small systems such as laptops and calculators, and These non-transmitting devices generate graphics by transmitting polarized light from surrounding or internal sources through liquid crystal materials that block or transmit light .
The
term liquid crystal (liquid crystal) refers to these compounds have crystalline structure of the molecule, and can flow like a liquid . Flatboard displays typically use linear liquid crystalline compounds, which tend to maintain the long axis arrangement of rods. So a flat panel monitor is availablethe linear liquid crystal composition, shown in 2.15. There are two glass panes, each with a light polarizer, and the other to form a suitableangle, the interior is filled with liquid crystal material. The horizontal transparent conductor line is discharged on a board and a vertical transparent conductor is placed on the other board .column. Defines a pixel position at the intersection of the row and column conductors. Normally, the molecules are arranged in the "open state" as shown in Figure 2.15. After thethe polarized light of the material is distorted so that it passes through the opposite polarizer, thus reflecting it to the observer. If you want to turn off pixels, we canto place the voltage on two intersecting conductors, aligning the molecules so that the polarized light is no longer distorted. This type of flat panel display device is visible as a
passive matrix (Passive-matrix) LCD. The definition of the graph is stored in the refresh cache, which refreshes the screen at a rate of 60 frames per second, with the transmitting deviceThe same. When using solid state electronic devices, the backlight is often used, and the system is not completely dependent on the external light source. Different materials can be used.dye to display color, and place a triple color pixel in each screen position. Another way to make an LCD isplace a transistor at each pixel location and adopt thin-film transistor technology. The transistor is used to control the voltage at the pixel position andStop Liquid Product Unit chronic leakage. These devices are called
activation Matrix (Active-matrix) displays.
Computer graphics (i) video display equipment _5_ flat panel display
