| 摘要 |
PURPOSE:To reduce the consumption of electricity for prolonging the period of usability of a position surveying device and make it possible to recognize the finish of the position survey, by switching illuminating means so as to light the parts dimly during the position survey and light them brightly while the position survey is not performed. CONSTITUTION:Illuminating means 15, 16 consist of LED are arranged for backlight illumination of a display means 12 and an operation means 13 with consideration to the use at night or in a dark place. When a power supply means 17 is connected or a key of the operation means 13 is switched on to start the position survey, a controlling means 14 switches off the illuminating means 15 and switches on the illuminating means 16 to light the display means 12 and the operation means 13 dimly, gives instructions to a signal receiving means 10 and a position surveying means 11 to start the position survey, and makes the display means 12 show that it is under the position surveying at that time. When the position survey is finished, the controlling means 14 orders the display means 12 to show the results of the position survey and, switches off the illuminating means 16 and switches on the illuminating means 15 to light the display means 12 and the operation means 13 brightly. Consequently, the finish of the position survey can be recognized at once. |
