利用超声,蝙蝠在黑暗中可以自由地飞翔,这说明超声设备有可能使盲人活动更为自由.声手电筒或许是这类仪器最有价值的代表.英国超电子设备公司(Ultra Electronics)生产的第一批这类商品仪器采用了这个名字.在生产了1000个之后,这个原始样式便停产了.但是,称为雷达声灯的改进型手电简,在澳大利亚的墨尔本,由盲人雷达俱乐部研制出来了. With ultrasound, bats can fly freely in the dark, indicating that ultrasound equipment may make blind people more free. A flashlight may be the most valuable representative of such instruments. The British electronics giant (Ultra Electronics) produced by the A group of such instruments used the name, and the original model was discontinued after the production of 1000. However, an improved flashlight called a radar lamp was developed by the Blind Radar Club in Melbourne, Australia .