Authors have been engaged in the development of a feed forward driving technique, as part of the overdrive technique to improve the response time of liquid crystal displays. They have developed, in particular, a compression feed forward driving system in which an image compression technique was applied, focusing on a method of reducing the frame memory necessary for the signal processing of overdrives. Further, they are now studying motion adaptive CODEC feed forward driving that reduces the amount of overdrive errors by adding a motion-adaptive process to the image decoding section in cFFD. This paper discusses macFFD that does not use SDRAM as the overdrive for entry model LCD TVs. Setting the image compression ratio to 1/10 or so will enable the fabrication of frame memory for overdrive for SDTV using SRAM.
IntroductionImprovement of the performance of the display of motion pictures has been recently requested for liquid-crystal (LC) panels, in addition to the viewing angle, brightness, contrast and the gamut of color reproduction. This demand has been accelerated by users' comparisons of motion picture display performance between LC panels and conventional display devices, or CRTs, and is also driven by the fully-grown market of LC TVs.In recent years, a number of techniques have been reported for improving the performance of displaying motion pictures, such as the overdrive technique to improve the response time of LC display units, black insertion, blinking and back light to improve hold type problems, and so on [1-4].On the other hand, some new measurement methods to quantify blurs in motion pictures displayed on LC panels have been also discussed. It is said that motion blurs on LC panels are attributable to the long response time of LCs and the temporal summation by hold type displays. The study of a new definition of response time and a new method of evaluation has been promoted because the conventionally used definition of LC response time cannot properly express such performance factors of displaying motion pictures [5][6][7][8].Among others, we have been intensively considering a method of reducing the frame memory required by overdrive after the development of feed forward driving (FFD), which is our firstgeneration overdrive [1]. Compression feed forward driving (cFFD), which is our second-generation overdrive technique, has already been developed [9][10][11]. This cFFD realized maintenance of performance and cost reduction through reducing the frame memory required by overdrive by means of the image compression technique.Further, we have started the study of motion adaptive codec FFD (macFFD), in which a motion-adaptive processing unit is added to the image decoding section of cFFD, as the third-generation FFD. The use of the motion-adaptive processing function in the image decoding section enables us to restrain the occurrence of unnecessary acceleration data in still pictures, which is one of features of cFFD, and at the same time, to reduce acceleration data errors in motion pictures [12].In th...