What is the display device and its classification?
Display | display device can be divided into VFD fluorescent display, lcd liquid crystal display, LED digital display, ECD electrochromic display, PDP plasma displays, EPD electrophoretic display and PLZT ferroelectric ceramics display.
A, LED digital display
(A) LED digital display structure principle
LED digital display, also known as LED, is more than just strip the semiconductor light-emitting diode according to a certain combination of connections shown in Figure 13-1.
LED digital display with common anode and common cathode of the points.
Common anode LED digital display in the LED cathode are connected together, the anode and as a public power | regulator positive. When the strokes electrode plus drive low, the corresponding strokes will be light.
Common cathode LED digital display of each light-emitting diode cathode are connected together, as the cathode and the negative power source connected to the public. When the strokes plus the electrode drive high, the corresponding section of the pen will light.
LED digital displays are generally driven by the integrated circuit, in order to display properly. Figure 13-2 is a common cathode LED digital display of a typical driver circuit.
(B) LED digital display types
1. Classified according to light and color light color LED digital display can be divided by red, orange, yellow and green variety. Color and light-emitting diodes doped semiconductor material and its quality related.
2. Sort by luminous intensity luminous intensity LED digital display can be divided according to normal brightness LED digital display and high brightness LED digital display.
3. Classified according to the median displayed by show-digit LED digital display can be divided into an LED digital display, dual digit LED display and several LED digital display.
Second, the liquid crystal display (LCD)
(A) liquid crystal display (LCD) structure principle
Liquid crystal display (LCD) is a passive type display device, is the use of liquid crystal electro-optical effect, the control environment through the exchange of electric light in the display section of the reflection (or transmission) to be displayed. Itself does not light, not dark environment in the light display.
Liquid crystal electro-optic effect is a kind of substance, it at a certain temperature range, both with unique birefringence of the crystal, but also has a liquid flow.
LCD can be divided into thermotropic and lyotropic liquid crystal into two categories. LCD using thermotropic liquid crystal. It is in the electric field, a change in molecular arrangement, the optical properties also will be changed.
Black and white LCD display is usually the upper and lower two stacked glass with a transparent electrode (left certain interval), surrounded by sealing together, sealing the border left a note on the entry. Vacuum from the injection port and into the liquid crystal material, the injection port sealed. In the glass on the lower surface of the paste a polarization direction perpendicular to the polarizer, coupled with a bottom reflector.
When the incident light through the polarizer (the polarization on the electrode surface with the liquid crystal molecules arranged in the same direction) polarized light injected into the formation of the liquid crystal layer, the liquid crystal layer is reversed 900, liquid crystal cell is transparent state, you can see the reflection plate . When the LCD box, inserted between two electrodes under certain current and voltage, the electrode parts of the liquid crystal molecules under the action of the electric field into the upper and lower glass surface vertically status, loss of optical activity at this time the liquid crystal layer can not change the direction of polarized light, so do not see the reflection plate, only to see the electrode (electrode can be made of numbers, characters or graphics) parts in black. Figure 13-3 is a liquid crystal display outline.
(B) the type of liquid crystal displays
1. Sort by conversion mechanism converting liquid crystal display according to the mechanism can be divided into twisted nematic (TN) type, the dynamic scattering (DS) type, guest and host (GH)-type, super twisted (STN)-type, electrically controlled birefringence (ECB), double frequency type, phase change (PC) type and storage type.
2. Classified according to drive by driving liquid crystal display can be divided into static and dynamic driving style-driven.
3. Use classification by use of liquid crystal displays can be divided into clocks, watches with calculator use, instruments | Instrument meter use, miniature color TV, computer monitor use, with DVD players, dot matrix display with the other.
4. Classified according to structure liquid crystal display according to the structure can be divided into reflective, transmissive and projector-type variety.
5. Classified according to connection press the LCD and the driver circuit can be divided into the connection between the conductive rubber connector and plug male connectors.