当发光物体的面积越大，本影就越小。因此科学家根据这个原理来发明了手术用

当发光物体的面积越大，本影就越小。因此科学家根据这个原理来发明了手术用的无影灯。

Results (English) 1:

When the area of ​​the luminous object is larger, the umbra is smaller. Therefore, scientists invented the shadowless lamp for surgery based on this principle.

Results (English) 2:

The larger the area of the glowing object, the smaller the shadow. So scientists invented the shadowless lamp for surgery based on this principle.

Results (English) 3:

The larger the area of the illuminated object, the smaller the umbra. So scientists invented a shadowless lamp for surgery based on this principle.