A dark green, round biconvex tablet with opaque coating.
深绿色，圆形不透明涂层双凸片。
2
This paper, in detail, introduced how to study the rule of image construction for biconvex lens by using the method of vision difference.
本文详细地介绍了如何运用视差现象研究凸透镜的成象规律。
3
The rule of adaxial image formation is studied, of the transmission light and reflected light through the two optical surfaces L_1 and L_2 of the biconvex lens.