| 摘要 |
PURPOSE:To prevent a visual field of observation from varying owing to temperature variation and a change with lapse of time by detecting the amplitude of a sample through an amplitude detector and comparing it with the reference voltage of a size reference voltage setting circuit, and controlling the amplitude of the sample. CONSTITUTION:The sample 3 on the ultrasonic microscope consisting of a high- frequency oscillator 1, ultrasonic wave transmitting element 2, ultrasonic wave receiver 4, receiver 5, and display device 6 is excited by an exciter 8. When the exciter 8 is driven, a side reference voltage for setting the size of the visual field of observation from the size reference voltage circuit 13 is selected by a reference voltage selecting device 14 and compared by a comparator 12 with the output of an amplifier 11 corresponding to the amplitude of the oscillation of the sample 3 detected by the amplitude detector 10; when the output of the detector 10 is larger, the output of a driving circuit 9 is suppressed by the output signal of the comparator 12, and when the detector output is smaller to the contrary, the output voltage of the circuit 9 is raised to obtain a visual field of observation having no variation all the time. |
