Kabushiki Kaisha Toshiba

Yoshiji Tsuzuki

Tsutomu Sakamoto

Masanori Fujiwara

Hisayuki Mihara

Toshio Obayashi

An automatic brightness correction apparatus for automatically correcting the brightness property of the image display device is configured to insert a test pulse at a predetermined level within a level range including an intermediate level to the video signal and displays the image of the test pulse on the video image display device, detect a deviation of the brightness of the image of the test pulse displayed on the video image display device from a benchmark, and correct the level of the video signal based on the detected deviation.

Automatic brightness correction apparatus for image display device

NTSC convergence adjusting data corresponding to a plurality of portions on a display screen is stored in a data storage section in advance. Convergence adjusting data is stored in a field memory in a NTSC scanning mode. Adjusting data transferred to the memory is supplied to a vertical interpolation circuit, and interpolation adjusting data between the adjusting points is created using the plurality of adjusting data and interpolation coefficients. Data output from the vertical interpolation circuit is A/D-converted, and supplied to a deflection coil through a low pass filter as a convergence correction signal. In a scanning mode, convergence adjusting data is created with use of NTSC convergence adjusting data by a control microcomputer so as to be stored in the frame memory.

Digital convergence apparatus

A field memory stores convergence adjusting data which corresponds to a plurality of points on a display screen. An interpolation calculation circuit creates interpolation convergence adjusting data for correction points located between adjacent adjusting points, using a plurality of adjusting data items and interpolation coefficients. The output of the interpolation calculation circuit is subjected to digital/analog conversion and passed through a low-pass filter, thereby forming a convergence correction signal. This correction signal is supplied to each deflection coil. At the time of creating interpolation adjusting data for a point located between adjusting points, an optimal interpolation coefficient is output from a ROM or a ROM, depending upon whether the point is included in the odd or even field.

A liquid crystal display system includes a liquid crystal display having liquid crystal pixel elements arranged in a matrix; data lines for driving pixel columns and scanning signal lines for driving pixel rows. The system has a circuit for supplying video signal to pixels through data lines and a scanning signal line controller for supplying a progressive scanning signal to the scanning signal lines. The data lines are driven by four sample-hold circuits. The first sample-hold circuit samples and holds video signals for pixels corresponding to odd rows on a first side of the screen and supplies them to data lines corresponding to the first side on the screen based on a first output directing signal. A second sample-hold circuit samples and holds video signals for pixels corresponding to even rows on the first side of the screen and supplies them to data lines corresponding to the first side on the screen based on a second output directing signal. A third sample-hold circuit samples and holds video signals for pixels corresponding to odd rows on a second side of the screen and supplies them to data lines corresponding to the second side on the screen based on a third output directing signal. A fourth sample-hold circuit samples and holds video signals for pixels corresponding to even rows on the second side of the screen and supplies them to data lines corresponding to the second side on the screen based on a fourth output directing signal.

Liquid crystal display driving system

A digital convergence apparatus using two different kinds of data to correct the convergence of odd and even scanning lines, respectively. A first memory stores data for the convergence correction corresponding to plural correction executing points aligned in the horizontal or vertical direction of a screen. A first static convergence data memory stores a first static convergence correction data for correcting the entire screen in the same direction, a second static convergence data memory stores a second static convergence correction data different from the first static convergence correction data only by an amount corresponding to the distance between the scanning lines. Selecting means select the output of the first or the second static convergence data memory according to the odd field period or the even field period. Adding means add the output of the selecting means to the data stored in the first memory. Vertical interpolating means interpolate the output of the adding means in the vertical direction, and a convergence correction coil corrects the convergence based on the output of the adding means.

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Saitama-ken, Japan

Yoshiji Tsuzuki