Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Taro Funamoto

Katsuyuki Arimoto

Takahiro Kobayashi

Yoshihito Ohta

Wataru Machidori

Yoshihito Ota

Yasuhiro Kumamoto

Kenji Nakao

Yoshinori Kobayashi

Takahisa Hatano

Seiji Kawaguchi

Yoshikuni Shindo

Kazuo Inoue

Katsuhiko Kumagawa

Yutaka Nio

Ichiro Sato

Tsugio Murao

Tetsuo Kariya

Fumlou Kameoka

Fumiou Kameoka

A signal converting section increases a transfer rate of an input image signal to be supplied to a liquid crystal panel and, at the same time, also inserts a non-image signal for applying a predetermined voltage to liquid-crystal cells in a space of the input image signal and supplies it as a picture-element signal to a source driver. To each picture cell, an input image signal and a non-image signal are sequentially written with positive or negative polarity. For all picture elements, after the input image signal is written, the non-image signal equal in polarity to the input image signal is always written. Furthermore, after the non-image signal is written, an image signal opposite in polarity to the non-image signal is always written. Thus, when an image is displayed on the liquid crystal panel in OCB mode, it is possible to prevent the occurrence of back transition and carry out image display evenly.

Liquid crystal display unit and driving method therefor

An image display apparatus and method provided for visually improving a sense of contrast by adjusting contrast and a light source to have a correlation. A characteristics detection part detects MAX, MIN, and APL (average) of an input signal. A control data generation part calculates Gain for amplifying a difference between MAX and MIN to a width of a dynamic range and Offset indicating the DC level to be shifted so that the input video signal amplified by Gain falls within the output dynamic range of a DC level adjustment part. A signal amplitude adjustment part amplifies the input video signal with reference to APL and in accordance with Gain. The DC level adjustment part shifts the DC level of the amplified input video signal in accordance with a value of Offset. A light source control part controls a light source so that a visual brightness level on a screen is equal to a brightness level of the input video signal.

Image display apparatus and image display method

An EPG extraction portion extracts EPG information; a program type decision portion decides the type of broadcast program using the extracted EPG information, and outputs a ratio modification signal to change the ratio of the image display interval to the black display interval according to the program type; a driving pulse generation portion generates a gate driver control signal which changes the write timing of a frequency-doubled image signal and frequency-doubled black display signal in one field interval, according to the ratio modification signal; and, a gate driver changes the write timing of the frequency-doubled image signal and frequency-doubled black display signal according to the gate driver control signal, to change the ratio of the image display interval to the black display interval.

Display apparatus and display apparatus drive method

An image display apparatus and method are provided for visually improving a sense of contrast by adjusting contrast and a light source to have a correlation. A characteristics detection part detects MAX, MIN, and APL (average) of an input signal. A control data generation part calculates Gain for amplifying a difference between MAX and MIN to a width of a dynamic range and Offset indicating the DC level to be shifted so that the input video signal amplified by Gain falls within the output dynamic range of a DC level adjustment part. A signal amplitude adjustment part amplifies the input video signal with reference to APL and in accordance with Gain. The DC level adjustment part shifts the DC level of the amplified input video signal in accordance with a value of Offset. A light source control part controls a light source so that a visual brightness level on a screen is equal to a brightness level of the input video signal.

In a baseband video transmission system for transmission of a video signal at a baseband based on the DVI standard, a transmitting device multiplexes a data signal representing data other than video during at least one blanking period of component video signals of the video signal to generate a DVI signal. A receiving device receives the DVI signal, and extracts the data signal from the received DVI signal.

Baseband video transmission system

When displaying moving images by using liquid crystal panels and others, a problem exists in that tail streaks occur, and image degradation is resultantly caused. To solve this problem, an echo suppression circuit divides a video signal into a pair composed of two successive frames for comparison between these two frames in signal level for the purpose of suppressing an echo phenomenon occurring when a liquid crystal panel displays video signals including moving images. If these two frames are not the same in signal level, the signal is accordingly corrected so as to equalize the signal level of these frames. Based on the video signals and others corrected by the echo suppression circuit, a controller operates the liquid crystal panel with AC drive through a source driver and a gate driver. As such, the drive voltage used to operate the liquid crystal panel with AC drive is adjusted so as to be balanced between positive and negative. In this manner, the tail streaks are prevented when displaying moving images.

A liquid crystal display apparatus is provided with a detecting section () for detecting a value of a parameter that causes fluctuations in a back transition occurrence condition; a calculating section () for determining, in accordance with the detection value of the detecting section, at least one of a ratio of an time period of applying a high voltage with respect to one frame period, the high voltage being applied to the liquid crystal panel in order to prevent back transition, a magnitude of the high voltage, and an applied voltage corresponding to white display; and a controller () for alternately outputting a video signal and a non-image signal for applying the high voltage and driving the liquid crystal panel on a condition in accordance with the determination result of the calculating section. With this, it is possible to always display video irrespectively of fluctuation in the back transition occurrence condition.

Liquid crystal display apparatus and drive method thereof

A doubler part doubles frequencies of video signals. A drive control circuit generates, in response to a synchronizing signal outputted from the doubler part, PWM dimming frequency information such that a PWM dimming frequency f and a black display ratio B satisfy the relationships f&#x2267;25B+250 and B&#x3e;10, and provides such information to a PWM dimming signal generation circuit. In addition, the drive control circuit drives a gate driver and a source driver such that one frame period is divided into an image display period and a black display period. The PWM dimming signal generation circuit generates, in response to a synchronizing signal and the PWM dimming frequency information, a PWM dimming signal and provides the PWM dimming signal to a lighting circuit. The lighting circuit activates a backlight device with dimming, in response to the PWM dimming signal. This configuration reduces colored interference fringes in a liquid crystal display device resulting from the combination of a black insertion drive technique and a PWM dimming technique.

Liquid crystal display device

A liquid crystal display device capable of suppressing the occurrence of a back transition in OCB cells and displaying excellent images as well as a driving method thereof are provided. One frame period has a first period Pfor writing a signal for initializing the state of a liquid crystal in pixel cells and a second period for writing pixel data in correspondence with an image signal in pixel cells, and a voltage level to be applied to each pixel cell is set in the first period such that each pixel cell retains a voltage Vsup higher than that in the second period.

Liquid crystal display device using OCB cell and driving method thereof

A signal converting section increases a transfer rate of an input image signal to be supplied to a liquid crystal panel and, at the same time, also inserts a non-image signal for applying a predetermined voltage to liquid-crystal cells in space of the input image signal and supplies it as a picture-element signal to a source driver. To each picture cell, an input image signal and a non-image signal are sequentially written with positive or negative polarity. For all picture elements, after the input image signal is written, the non-image signal equal in polarity to the input image signal is always written. Furthermore, after the non-image signal is written, an image signal opposite in polarity to the non-image signal is always written. Thus, when an image is displayed on the liquid crystal panel in OCB mode, it is possible to prevent the occurrence of back transition and carry out image display evenly.

A liquid crystal display apparatus that uses a backlight for display includes a video signal time compression circuit for compressing a video signal in the time axis direction and outputting the time-compressed video signal, an LCD controller for driving a liquid crystal panel based on the time-compressed video signal, and a source driver and a gate driver. The liquid crystal display apparatus also includes a motion detection circuit for detecting the amount of motion of a display image based on the video signal, a PWM modulation pulse generation circuit for generating modulation pulses different in frequency according to the detection result from the motion detection circuit, and an inverter for lighting up the backlight based on the modulation pulses, to thereby enable reduction of image contour blurring in a moving image and reduction of flicker in a still image.

Image display apparatus and method

Provided are an image display apparatus and method capable of visually improving a sense of contrast by adjusting contrast and a light source to have correlation. A characteristics detection part detects MAX, MIN, and APL of an input signal. A control data generation part calculates Gain for amplifying a difference between MAX and MIN to a width of a dynamic range and Offset indicating the DC level to be shifted so that the input video signal amplified by Gain falls with in the output dynamic range of a DC level adjustment part B. A signal amplitude adjustment part A amplifies the input video signal with reference to APL and in accordance with Gain. The DC level adjustment part B shifts the DC level of the amplified input video signal in accordance with a value of Offset. A light source control part controls a light source so that a visual brightness level on a screen is equal to a brightness level of the input video signal.

Image display device and image display method

A video display monitor employs interpolation which maintains sharpness in images which have large differences in signal levels of picture elements and assuring smoothness of images such as lamps which have small differences in signal levels. The difference in the signal level differences of respective adjacent picture elements is detected by delay and subtraction. A decoder produces a signal for interpolation based on the input of an interpolation coefficient and the absolute value of the interpolation coefficient which is output from an absolute value detector.

Video display monitor employing image interpolation

A pixel conversion apparatus includes a sync separator for separating a sync signal from an input signal, a pixel conversion information analyzer for analyzing how to convert the number of pixels to display the input signal as an image from the input signal and a picture display area, a timing signal generator for generating a timing signal for displaying an image according to the outputs of the sync separator and the pixel conversion information analyzer, a pixel converter for processing a pixel conversion of the input signal according to the output of the timing signal generator, an interpolator for processing a pixel interpolation when the pixel to be interpolated generated by pixel conversion at the pixel converter, and a sync signal generator for generating a sync signal for displaying the input signal as an image. Because the relation between the input signal and the image display area is previously analyzed and processed, there is no lack, or display by mistake, of image information included in the input signal and a high quality image can be effectively displayed on the picture display area of the display device.

Growing community of inventors

Mino, Japan

Taro Funamoto