| 摘要 |
PURPOSE:To instantaneously switch a displaying range being displayed to a basic displaying range, by additionally installing a reference displaying range signal generating section and displaying range setting signal selecting section to a display range changing circuit. CONSTITUTION:When a displaying distance selecting section 1 and off-center controlling section 2 are operated, a displaying range is determined and enlarged display, etc., in a desired range are performed. When a displaying range selecting section 4 is operated under this condition, an additionally installed displaying range setting signal selecting section 5 selects a reference distance signal 12 and reference off-center signal 13 from an additionally installed reference displaying range signal generating section 3 and display of a basic range, such as full range, etc., is performed. When the selecting section 4 is operated again, the display is returned to the original enlarged display. Thus switching between a currently displayed displaying range and basic displaying range can be performed instantaneously without operating off-center controlling section 2 together with the displaying distance selecting section 1. |
