| 摘要 |
PROBLEM TO BE SOLVED: To prevent occurrence of a detecting error due to remarkable difference of detecting levels owing to a difference of a method for manufacturing a printed board in the case of detecting the mark, or gold plating of black ground mark, gold plating of glass ground, gold plating of copper ground or solder plating of glass ground. SOLUTION: The method for detecting a board mark comprises the steps of disposing a special diffusion sheet 3 on an upper surface of a board 1 displaying the mark as a reference to place a screen plate for printing or above with a variable gap G, emitting a light from an illuminator 4 disposed in variable height H above the sheet 3, imaging the board 1 over the sheet 3 by a camera 5, and binarizing its video signal. |
