Panasonic Liquid Crystal Display Co., Ltd.

Hitachi Displays, Ltd.

Renesas Technology Corp.

Renesas Electronics Corporation

Japan Display Inc.

Takuya Eriguchi

Yasuyuki Kudo

Norio Mamba

Naoki Takada

Akihito Akai

Kazuo Okado

Tsutomu Furuhashi

Hideo Sato

Hiroshi Kurihara

Naruhiko Kasai

Mitsuru Goto

Yoshinori Aoki

Yoshihiro Kotani

Shinichi Iwasaki

Hiroki Aizawa

Yuki Okada

In RGB time division drives, there is capacitor coupling due to the effects of fluctuation in the drain lines, and thus, the image quality deteriorates (lateral smearing), so that the display brightness becomes different from the desired display brightness due to delay in the convergence of the fluctuation of the common potential, and thus, it is a goal to prevent the image quality from deteriorating (lateral smearing). In RGB time division drives, the order of time division is switched for each frame, or in the direction of the horizontal lines.

Display device with a source signal generating circuit

Provided are a power supply circuit and a display device which are capable of enhancing power efficiency even when applied to a display panel whose current consumption varies. The power supply circuit boosts and outputs an input voltage using a booster chopper circuit. A frequency control circuit changes a frequency of a clock signal, which controls a switch of the chopper circuit, in accordance with a load of the power supply circuit. The frequency control circuit divides an operation of the display device into a display effective period at a high load and a vertical retrace period at a low load, based on a vertical synchronizing signal and a horizontal synchronizing signal. The frequency control circuit sets the frequency of the clock signal in a high-load period to be higher than that in a low-load period.

Power supply circuit of display device and display device using the same

Disclosed herein is a display device in which input data is written to a RAM as current frame data and read from the RAM as preceding frame data. Then, the current frame data and the preceding frame data are added up in a correction circuit and the result is subjected to an overdriving processing. After this, the processed (over-driven) data is assumed as current frame corrected data, which is then written to the RAM. The written corrected data is read from the RAM and subjected to a double-speed driving processing.

Display device

A touch sensor () comprises a plurality of X-coordinate electrodes, a plurality of Y-coordinate electrodes placed crossing the X-coordinate electrodes with an insulating layer therebetween, a plurality of X-coordinate auxiliary electrodes which are extended from X-coordinate electrodes, and a plurality of Y-coordinate auxiliary electrodes which are extended from Y-coordinate electrodes, the plurality of X and Y-coordinate electrodes being placed in a two-dimensional matrix form on a display surface of a display device () for detecting a change of capacitance due to pressing. A detection circuit () which detects a change in capacitance of the touch sensor (), an analog-to-digital converter () which converts a detection output of the detection circuit () into digital data, a touch panel control circuit () which determines a touched coordinate, and a primary control circuit () which receives input of touch coordinate data from the touch panel control circuit () are provided.

Screen input-type image display system

In consideration of the current leakage path of a liquid crystal panel and a signal line voltage fluctuation due to the current leakage path, a &#x3b3; adjusting function (second driving method) is applied for each divided period in the first driving method. In a signal line driving unit, a gray scale voltage obtained by adding or subtracting a voltage fluctuation value different in each of the output periods of each gray scale is generated, and a gray scale voltage taking the voltage fluctuation value into consideration is applied to a signal line.

Display driver

A liquid crystal display is provided with: a tap adjustment register for adjusting a gray scale level to a gray scale voltage in intermediate portions close to the end portions of the gamma characteristic; and a partial-voltage-ratio adjustment register for adjusting a ratio of a gray scale voltage among a plurality of gray scale levels in the intermediate portions close to the end portions of the gamma characteristic, in addition to an amplitude adjustment register for adjusting an amplitude of a gamma characteristic which determines a relation between gray scale levels and gray scale voltages or brightness levels on a display panel; a gradient adjustment register for adjusting a gradient of intermediate portions of the gamma characteristic while fixing end portions of the gamma characteristic; and a fine adjustment register for finely adjusting the intermediate portions of the gamma characteristic for each gray scale level.

In a display apparatus of a hold type represented by a TFT liquid crystal display, blurring of dynamic picture when the dynamic picture is displayed is improved. One frame is divided into dark fields and light fields. A dark brightness gradation voltage approaching to display of black as near as possible is generated in the dark fields and a light brightness gradation voltage for compensating the brightness reduced by the dark fields is generated in the light fields. At this time, low gradation voltages (VP to VP) or high gradation voltages (VP to VP) in the dark or light brightness gradation voltages are set to the same potential.

Display apparatus

A driving circuit provided by the present invention is characterized in that the driving circuit selects a gray-scale voltage in accordance with high-order bits of display data from a group of gray-scale voltages with their voltage level varying step by step from fractional time period to fractional time period, which are set in advance, and outputs the selected gray-scale voltage during a time period between the start of a scanning period and a time at which a number assigned to a fractional time period matches quantitative information contained in low-order bits of the display data. In addition, the driving circuit provided by the present invention is also characterized in that the time ratio of the first fractional time period is set at a relatively high value while the time ratios of the second and subsequent fractional time periods are each set at a relatively low value.

Growing community of inventors

Yokosuka, Japan

Takuya Eriguchi