| 摘要 |
PURPOSE:To inspect out-of-focus of a CRT, by displaying a lattice-like pattern and a pattern indicating the maximum value of luminance, on the CRT display face. CONSTITUTION:A lattice-like pattern and a wide width pattern indicating the maximum value of luminance are displayed on the CRT display face. A picture of the CRT display face is inputted to a TV camera 9 through a lens 8, and a luminance value of a test pattern being displayed is measured. A difference value 1 of a tube face luminance part measured value 13 and the maximum luminance part measured value 14, and a difference value 2 of the maximum luminance measured value 15 of the lattice pattern part and the minimum luminance measured value 16 are derived. Subsequently, the difference value 2/ difference value 1 is derived by a dividing circuit 17. By comparing this value with a reference data 19 derived in advance, a focus is inspected quantitatively. |
