Sharp Kabushiki Kaisha Corporation

Nobuhiro Kuwabara

Hiroshi Yoneda

Hajime Washio

Shigeto Yoshida

Kazuhiro Maeda

Yasushi Kubota

Tamotsu Sakai

Akihito Jinda

Ichiro Shiraki

Sachio Tsujino

Yousuke Nakagawa

Hiroaki Sugiyama

Ichiroh Shiraki

Yuji Asoh

In this liquid crystal display device, a potential propagation line (PVID) and video signal lines SL() to SL(M) are connected via coupling capacitive elements Cp() to Cp(M), and a capacitance drive circuit () causes the potential of the potential propagation line (PVID) to change in the same direction in which the potential of a video signal S(m) varies during a period of nonselection. As a result, even if there is not enough time to perform a precharge operation, the potentials of video signal lines can be similarly raised or lowered without performing a precharge operation.

Display device and display method

By reducing the potential drop of a storage node that occurs due to feedthrough, the capacitance of a storage capacitor is reduced and sensor sensitivity is improved. In a photosensor, the first terminal of a storage capacitor (C) and the gate of a MOS transistor (M), which outputs a signal in accordance with the potential of a storage node (N), are connected to the storage node (N). A forward biased pulse voltage is supplied to the anode of a first photodiode (DS) in a reset period, and a reverse biased voltage is supplied to the anode of the first photodiode in a storage period and a readout period. A reverse biased voltage is supplied to the anode of a second photodiode (DM) in all operation periods. A voltage that keeps the potential of the storage node lower than the threshold value of the MOS transistor (M) is supplied to the second terminal of the storage capacitor in the reset period and the storage period, and a voltage that thrusts the potential of the storage node (N) upward to the threshold value of the MOS transistor (M) or higher is supplied to the second terminal of the storage capacitor in the readout period.

Photosensor operating in accordacne with specific voltages and display device including same

In a vertical retrace interval, a pre-charge potential or a signal potential is applied to each polarity for AC driving liquid crystal at least once each, so as to maintain fluctuations in pixel potential between the positive polarity side and the negative polarity side uniform, and minimum required potentials are supplied to the data signal line, thereby suppressing decrease in image quality without significantly increasing power consumption.

Image display device and driving method of the same

An image display device of this invention includes a pre-charging voltage stabilizing section having current controlling means and charge holding means which respectively include a resistor and a capacitor to stabilize a pre-charging voltage. The charge holding means holds a voltage to be supplied to data signal lines, and the current controlling means suppresses a current flow from a control signal generating circuit, thereby suppressing power fluctuation at the control signal generating circuit. This suppresses fluctuation in the pre-charging voltage and enables data signal lines to be charged to a predetermined voltage, thereby suppressing deterioration of image quality and an increase in power consumption of the image display device. Further, when using the pre-charging voltage stabilizing section and setting a portion of a display as a video data non-display area avoiding display of video data in a non-match image display mode to display at fixed brightness in the video data non-display area by a pre-charging voltage from a pre-charging circuit, a control signal is suspended in a fixed period, thus realizing a non-match image display mode to display a video image of an aspect ratio different from that of a screen of a display without impairing an image quality, and saving power.

Image display device and driving method thereof

A driving method for an active-matrix-type image display in which: in the case when the number of divisions of a video signal decreases in accordance with the scanning frequency of an original video signal, eight video signal lines through are divided into groups the number of which corresponds the reduced number of divisions so that the same video signal is inputted to the video signal lines belonging to the same group; and four systems of shift registers SRA through SRD are also divided into groups, SRA, SRB, SRC and SRD so that the same shift clock signal is inputted to the same group. With this method, even upon application of the device to a usage having a different scanning frequency, the construction of the external circuits are optimized so as to fit the different scanning frequency, and the shared use of the substrate is available so that cost reduction is achieved.

Active-matrix-type image display and a driving method thereof

A delay detecting section detects the phase difference between a first detection signal as a reference and a second detection signal produced by delaying the first detection signal with part of a data signal line driving circuit itself or part of a circuit formed by the same process as the data signal line driving circuit. A phase adjusting section presumes an internal delay of the data signal line driving circuit, and adjusts the phase difference between a clock signal and start signal, and a video signal so that the data signal line driving circuit samples the video signal at an appropriate timing. These structures prevent a lowering of the image quality due to a difference in the timings of the video signal and sampling signal, and provide an image display device capable of displaying a good-quality image with a simple circuit structure.

Growing community of inventors

Tenri, Japan

Nobuhiro Kuwabara