The principle of adjustment of foci is introduced and a method to realize it is given.Lensmeter can realize auto adjustment of foci and measure the parameter of eyeglass.

• 文中介绍了全自动数字查片仪的自动调焦原理,并对其实现方法进行了设计,实现了查片仪的自动调焦和眼镜片各项参数的测量。