Dynamic focusing device for cathode ray tube

A dynamic focusing device for cathode ray tubes, said device comprising:

• a crosshatch pattern generating means responsive to horizontal and vertical synchronizing signals for providing a surface of said cathode ray tubes with a crosshatch pattern indicating an adjustment point at which focusing control is carried out, said crosshatch pattern generating means comprising circuit means for producing a cursor indicating the adjustment point for carrying out the focusing control, and for providing a brightness reversed crosshatch pattern at said adjustment point;
• an input means for choosing said adjustment point and for controlling the focus at said chosen adjustment point;
• a correction data setting means having a memory unit for storing a correction data necessary for proper focusing about said adjustment point, said correction data setting means being coupled to said input means in order to produce said correction data;
• an interpolation data calculating means for producing interpolation data between two adjacent adjustment points located in a vertical direction by calculating the correction data of said two adjacent adjustment points, said interpolation data calculating means comprising:
• a subtracter for calculating a difference between the correction data of said two adjacent adjustment points located in a vertical direction,
• a multiplier for multiplying an output of said subtracter by a predetermined factor, and
• an adder for adding an output of said multiplier and one of the correction data of said two adjacent adjustment points;
• a latch and digital to analog converting means for converting said correction data and said interpolation data into an analog form;
• and
• an output means having an interpolation filter for interpolating characteristics between two adjacent adjustment points located in a horizontal direction, said output means being coupled to said latch and digital to analog converting means and supplying an output signal to said cathode ray tubes.

A dynamic focusing device for cathode ray tubes, said device comprising:

• a crosshatch pattern generator responsive to horizontal and vertical synchronizing signals for providing a surface of said cathode ray tubes with a crosshatch pattern indicating an adjustment point at which focusing control is carried out, said crosshatch pattern generator comprising a circuit for producing a cursor indicating the adjustment point for carrying out the focusing control, and for providing a brightness reversed crosshatch pattern at said adjustment point;
• a keyboard for choosing said adjustment point and for controlling the focus at said chosen adjustment point;
• a correction data setting circuit having a memory unit for storing a correction data necessary for proper focusing about said adjustment point, said correction data setting circuit being coupled to said keyboard in order to produce said correction data;
• an interpolation data calculating circuit for producing an interpolation data between two adjacent adjustment points located in a vertical direction by calculating the correction data of said two adjacent adjustment points;
• a latch and digital to analog converter for converting said correction data and said interpolation data into an analog form;
• and
• an output circuit having an interpolation filter for interpolating characteristics between two adjacent adjustment points located in a horizontal direction, said output circuit being coupled to said latch and digital to analog converter and supplying an output signal to said cathode ray tubes.

A dynamic focusing device for cathode ray tubes, said device comprising:

• a crosshatch pattern generating means coupled to a video signal processing circuit of direct-view television devices or projection television systems responsive to horizontal and vertical synchronizing signals, which are included in composite television signals, for providing a surface of said cathode ray tubes with a crosshatch pattern indicating an adjustment point at which focusing control is carried out, said crosshatch pattern generating means comprising circuit means for producing a cursor indicating the adjustment point for carrying out the focusing control, and for providing a brightness reversed crosshatch pattern at said adjustment point;
• an input means for choosing said adjustment point and for controlling the focus at said chosen adjustment point;
• a correction data setting means having a memory unit for storing a correction data necessary for proper focusing about said adjustment point, said correction data setting means being coupled to said input means in order to produce said correction data;
• an interpolation data calculating means for producing interpolation data between two adjacent adjustment points located in a vertical direction by calculating the correction data of said two adjacent adjustment points;
• a latch and digital to analog converting means for converting said correction data and said interpolation data into an analog form;
• and
• an output means having an interpolation filter for interpolating characteristics between two adjacent adjustment points located in a horizontal direction, said output means being coupled to said latch and digital to analog converting means and supplying an output signal to said cathode ray tubes.

A dynamic focusing device for cathode ray tubes, said device comprising:

• a crosshatch pattern generating means coupled to a video signal processing circuit of direct-view television devices or projection television systems responsive to horizontal and vertical synchronizing signals, which are included in composite television signals, for providing a surface of said cathode ray tubes with a crosshatch pattern indicating an adjustment point at which focusing control is carried out, said crosshatch pattern generating means comprising circuit means for producing a cursor indicating the adjustment point for carrying out the focusing control, and for providing a brightness reversed crosshatch pattern at said adjustment point;
• an input means for choosing said adjustment point and for controlling the focus at said chosen adjustment point;
• a correction data setting means having a memory unit for storing a correction data necessary for proper focusing about said adjustment point, said correction data setting means being coupled to said input means in order to produce said correction data;
• an interpolation data calculating means for producing an interpolation data between two adjacent adjustment points located in a vertical direction by calculating the correction data of said two adjacent adjustment points, said interpolation data calculating means comprising:
• a subtracter for calculating a difference between the correction data of said two adjacent adjustment points located in a vertical direction,
• a multiplier for multiplying an output of said subtracter by a predetermined factor, and
• an adder for adding an output of said multiplier and one of the correction data of said two adjacent adjustment points;
• a latch and digital to analog converting means for converting said correction data and said interpolation data into an analog form;
• and
• an output means having an interpolation filter for interpolating characteristics between two adjacent adjustment points located in a horizontal direction, said output means being coupled to said latch and digital to analog converting means and supplying an output signal to said cathode ray tubes.