一． 基本专业术语

Two. Several types of LCD products
Position display, character display, graphics display
Character based display module (LCM), the character LCD is used to display characters and figures, for graphics and Chinese characters display mode and bit section LCD. Character LCD generally have the following resolution, 8 x 1, 1 x 16, 2 x 16, 4 x 16, 2 x 20, 20 x 4, 20 x 2, 40 x 4, 2 x 40, 8 (16, 40), 1 (2, 4) is the number of characters, such as C2002A character LCD.
Graphic dot matrix display module (LCM), which can display characters and dynamic picture LCD. We will be divided into TN, STN, FSTN, TFT, and so on. LCD class TN because of its limitations, only for the production of character based liquid crystal display module;
LCD products, from the point of view of selection, people tend to divided into the following categories: a type (also known as 8 words), character and graphic dot formation.
The common type LCD module is composed of 8 parts, that is, 8 words and one point, only to show the number and the number of letters, if you must display a few characters, Chinese characters and other symbols, generally need to be customized, can be displayed by the characters, Chinese characters and other symbols in the specified position.
The LCD class STN module is generally small and medium size, both monochrome, but also a pseudo color; TFT class display module, from small to large, and almost all of the true color display module. In addition to the LCD class TFT, the general small LCD are built in controller (controller concept is equivalent to the master chip on the card), directly to provide MPU interface, and large and medium-sized LCD, to control the display, it needs an external controller, circuit is very complicated.
Three. Different types of LCD products
LCM, LCD terminal
LCD refers to the LCD glass panels that have been packaged and the lead electrode is not included in the LCD driver and the controller, which is the most primitive state of all LCD products. Market directly to the user's glass products is limited to the low density of the bit segment products.
LCM (LCDModule), the liquid crystal display module, refers to the glass and LCD drive integrated into the LCD display products, which provides a standard LCD display driver interface (4, 8, VGA, etc.), the user in accordance with the requirements of the interface to control the LCD display. LCD LCM LCM can be more convenient for the use of the control system. However, for large size or color of the LCD display, but for large size or color LCD display, the general will take control system quite most of the resources or simply can not achieve control, such as 320 color LCM, such as 8 color MCS51, such as 20 color MOVX, such as 320 color 1.465MB, such as color, such as 240256 color, such as 20 color 421.875MHz, such as color 11.71875Mb, 20 field / second (ie 1. 240 per second. Huge.
LCD terminal refers to the LCD display all the devices or functional modules integrated into the LCD display products, due to the vast majority of display and control work in the end, so it only needs to provide a low speed standard serial interface can be easily achieved by a variety of display functions. Because LCD products, especially large-scale LCM products, need to deal with large amount of information, software and hardware design of the complex, is a not small challenge to engineers in general, and LCD terminal will free the user from tedious LCM development, debugging, greatly speeding up the progress in the development of products, and due to the professional division of labor to ensure the stability of the products, production and maintenance are more convenient. In general, in order to facilitate the use of the user, LCD terminal is often integrated with the keyboard and touch screen interface, so that the design of human-computer interaction more flexible and convenient.
In short, the computer display system analogy, glass is equivalent to the monitor of the monitor, LCM is equivalent to a monitor, while the LCD terminal is equivalent to a collection of graphics cards, boards and displays (such as banks, logistics systems are widely used in the display terminal or POS terminal) users in the choice of LCD products, according to their own circumstances, combined with the following several points to consider:
1, the glass is suitable for the bit section type, the low cost application, needs the external drive or the monolithic microcomputer as the LCD drive, takes up some system resources, but this way is more flexible, the cost is also relatively low;
2, LCM is suitable for the large volume of products, the cost of the more prominent contradictions. Small batch, in general use no more than 1000, using the cost of LCM will because R & D investment, market opportunities lost and the use of LCD terminal is almost the same, or even higher, and for the production and maintenance of small batch products is a problem.
3, LCD terminal is suitable for small and medium volume application occasions, especially in the project application is very common, because the project's profit comes from the project efficiency, using LCD terminal to make the system integration can realize your display in the fastest time.
Four. LCD display principle and classification
In the field of flat panel display, LCD display (LCD), electro luminescence display (EL), plasma display (PDP), (LED) display, vacuum fluorescent display (VFD), etc..
Liquid crystal is a kind of special material which is different from solid, liquid and gaseous state in a certain temperature range.