Method for correcting digital convergence of multi-mode projection television

• US 5,627,605 A
• Filed: 03/07/1995
• Issued: 05/06/1997
• Est. Priority Date: 03/07/1994
• Status: Expired due to Term

• Current Assignee: LG Electronics, Inc. (LG Corporation)
• Original Assignee: Goldstar Jewellery LLC
• Inventors: Kim, Jae J.
• Primary Examiner(s): Kostak, Victor R.
• Application Number:
  US08/399,604
• Time in Patent Office: 791 Days
• Field of Search: 348/177, 348/180, 348/184, 348/189, 348/190, 348/745, 348/807, 315/368.12
• US Class Current: 348/745
• CPC Class Codes: H04N 9/28 Arrangements for convergence or focusing

Abstract

A method for correcting digital convergence performed with respect to four modes of NTSC, ED, MUSE and ZENITH only by adjusting the convergence for a single mode on a software basis includes the steps of adjusting a specific mode and calculating correction data based on adjustment data for the specific mode and storing adjustment data and correction data in memory, and calculating correction data of other modes based on correction data stored for the specific mode, thereby remarkably improving the accuracy of the convergence, facilitating adjustment time and adjustment itself, simplifying the system to cut down the price of the system while enabling digital convergence of a multi-sync projection television to apply it to household use and monitors for personnel computers and video conferencing.

Claims

1. A method for correcting digital convergence in multi-mode projection television comprising the steps of:

selecting a specific mode with respective adjusting points set on a controlling picture of a test pattern;

calculating adjustment data including the steps of setting scanning lines corresponding to the specific mode selected by use of a microcomputer and storing the adjustment data for adjusting points set by shifting the phase and adjustment pattern;

obtaining an adjustment data vector from the stored adjustment data and obtaining in advance for a selected mode respective coefficient values and initial values for respective finite differential equations by means of interpolation from the adjustment data vector; and

obtaining and storing correction data in a mode other than said selected mode, wherein said other mode is calculated by interpolating with the coefficient and initial values using the finite differential equations.

2. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 1, wherein said respective adjusting points are set by crosspoints of vertical and horizontal scanning lines in the outermost area of said controlling picture within said test pattern and by crosspoints of vertical and horizontal scanning lines corresponding to every two points in the vertical and horizontal directions.

3. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 2, wherein said adjusting points number 35 in total by seven in the horizontal direction and five in the vertical direction.

4. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 2, wherein said step of adjusting said specific mode and calculating said correction data comprises:

a phase and pattern shifting step for shifting phase and pattern on said controlling picture by selecting said specific mode;

an adjustment data storing step for storing adjustment data of respective adjusting points set as above;

an adjustment data calculating step for calculating and storing said adjustment data by performing first-order linear interpolation with respect to the crosspoint within an adjusted section by means of said stored adjustment data; and

a correction data calculating step for calculating and storing said correction data by means of said stored adjustment data.

5. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 4, wherein said correction data calculating step is carried out by:

calculating to store said correction data via fourth-order polynomial interpolation with respect to inside said controlling picture by means of said adjustment data; and

calculating to store said correction data via first-order linear interpolation with respect to outside said controlling picture by means of said adjustment data.

6. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 4, wherein said first-order linear interpolation is executed by the calculation via divided difference and step-by-step series.

7. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 4, wherein said first-order linear interpolation is executed by the calculation via Lagrange'"'"'s formula.

8. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 5, wherein said first-order linear interpolation is executed by the calculation via divided difference and step-by-step series.

9. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 5, wherein said first-order linear interpolation is executed by the calculation via Lagrange'"'"'s formula.

10. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 5, wherein said fourth-order polynomial interpolation is executed by the calculation via divided difference and step-by-step series.

11. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 5, wherein said fourth-order polynomial interpolation is executed by the calculation via Lagrange'"'"'s formula.

12. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 4, wherein said step of calculating correction data of other modes is carried out by:

calculating to store said correction data via fourth-order polynomial interpolation with respect to inside said controlling picture by means of said adjustment data; and

calculating to store said correction data via first-order linear interpolation with respect to outside said controlling picture by means of said adjustment data.

13. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 12, wherein said first-order linear interpolation is executed by the calculation via divided difference and step-by-step series.

14. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 12, wherein said first-order linear interpolation is executed by the calculation via Lagrange'"'"'s formula.

15. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 12, wherein said fourth-order polynomial interpolation is executed by the calculation via divided difference and step-by-step series.

16. A method for correcting digital convergence of a multi-mode projection television as claimed in claim 12, wherein said fourth-order polynomial interpolation is executed by the calculation via Lagrange'"'"'s formula.

17. A device for correcting digital convergence of multi-mode projection television comprising:

a remote controller for generating pattern changing data in response to convergence correction;

microcomputer means for providing adjustment data from memory and for calculating correction data from the adjustment data upon input of the specific mode after storing the adjustment data from the pattern changing data in memory, obtaining adjustment data vectors from the adjustment data, obtaining in advance by interpolation coefficients and initial values for the specific mode for use in finite differential equations and determining correction data for the specific mode;

correction data storing means for storing the correction data obtained by the microcomputer; and

correction data outputting means for outputting the correction data stored in the correction data storing means to correction current convergent means in response to a control signal of the microcomputer.