| 摘要 |
PURPOSE:To adjust by the user or automatically optimize the degradation of image quality due to variation of a peripheral magnetic field by permitting the user to freely shift a horizontal electron beam position in an entire screen according to the state of the screen. CONSTITUTION:Horizontal deflection data read out by a DMA controller 41 from a deflection memory 42 into which deflection data adjusted in their certain status during the operation of an image display device are written is latched by a horizontal deflection data latch 44h. Correction data common to an entire screen is added to this data by means of an adder 46a and an output timing adjusting latch 46b and sent to a horizontal deflection D/A43h. Then the entire electron beam is moved by the correction data in the horizontal direction. Thereby, even if the peripheral magnetic field such as geomagnetic field is varied and the electron beam of the entire screen is shifted, the user himself can recover its original status by performing adjustment by using the correction data. |
