tailieunhanh - composite 2012 Part 9

Tham khảo tài liệu 'composite 2012 part 9', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Active-Matrix Liquid Crystal Displays - Operation Electronics and Analog Circuits Design 153 Direct addressing method The first used addressing method was the direct method. According to this method its segment is directly connected and controlled individually by the peripheral electronics. The segments are arranged in such way so that they can produce the desired icon. The most common arrangement is the 7-segments shown in fig. 5 used in simple alphanumerical displays such as calculators and watches. In this method no multiplexing is available and this is the reason for only being used in low information content applications. In the direct method the smallest controllable component for the image production is called segment instead of pixel which will be used in the two other addressing methods. Fig. 5. 7-Segment arrangement with direct addressing method. Passive matrix addressing method As the displays and the information content were getting larger the need for more picture elements was arisen. The solution to this problem was the modification of the segments arrangement into a pixels matrix with M rows and N columns. In this method each pixel can not be controlled individually and a multiplexing addressing approach has to be realized. The new multiplexed addressing method was the passive matrix PM . The configuration of the passive matrix addressing method is shown in fig. 6. The passive matrix is a one-line-at-a-time driving method. During the programming time a pulse from the row peripheral driver activates all the pixels of the programming line and at the same time the data voltage is delivered to the storage capacitor and the liquid crystal through the peripheral column driver. Passive matrix is the addressing method with the minimum number of interconnections. For example for an M rows and N columns array the direct method needs MxN interconnections while the passive matrix method needs M N interconnections. Furthermore passive matrix is the .