Kabushiki Kaisha Toshiba

Toshio Obayashi

Tsutomu Sakamoto

Hisayuki Mihara

Yoshiji Tsuzuki

Masanori Fujiwara

Takayuki Arai

Masao Yanamoto

An analog-to-digital converter converts a video signal into a digital video signal consisting of N bits and outputs the converted signal. A correction value memory stores correction data consisting of M bits which is used to correct the difference in luminance between display pixels on a display. A multiplier multiplies the video signal consisting of N bits output from the analog-to-digital converter by the correction data consisting of M bits stored in the correction value memory, and outputs a video signal consisting of L bits with which the difference in luminance between display pixels on the display is corrected.

Video display apparatus for correcting luminance difference between display pixels

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.

Growing community of inventors

Fukaya, Japan

Toshio Obayashi