SHORT DISTANCE VISUAL ACUITY TESTER CAPABLE OF AUTOMATICALLY CONTROL ANGLE OF MIRROR FOR CHANGING PATH OF LIGHT

摘要

PURPOSE: A short distance visual acuity tester is provided to automatically control the angle of a mirror for changing path of light even without using an expensive position sensitive detector sensor. CONSTITUTION: A short distance visual acuity tester comprises an ultrasonic transmitting/receiving processing module for generating ultrasonic waves to the bottom where an examinee is positioned, and receiving ultrasonic waves reflected from the bottom; a data processing module connected to the ultrasonic transmitting/receiving processing module, and which outputs the rotation control signal including the rotating angle and rotating direction of a rotatable mirror in accordance with the visual height of the examinee; and a rotating unit arranged in a visual acuity tester body(60) such that the rotating unit rotates the rotatable mirror in accordance with the rotation control signal output from the data processing module.