The curvature radius of the optical lens, I believe that many of you here don’t know the optical lens very well. The lens is an object that can magnify and reduce the refraction of light. It is generally used in the optical field, such as car lights, flashlights, wall washers, LED lights and other fields. For many people asking questions on the Internet that they don’t understand the radius of curvature of an optical lens, we will explain it to you today.

The relationship between the focal length of the lens and the radius of curvature

Assuming that the curvature radii of the front and rear surfaces of the lens are r1, r2, the center thickness of the lens is d, and the refractive index of the material used for the lens is n, then the object focal length of the front surface is f1=-r1/(n-1), and the focal length of the phase focal length is f1' =nr1/(n-1), the object focal length of the back surface is: f2'=nr2/(n-1), the phase focal length is: f2'=-r2/(n-1), and then the total focal length is: f'=-f1'*f2'/(d-f1'+f2). The object focal length is equal to the negative focal length.

The radius of curvature is mainly used to describe the degree of curvature of a curve somewhere on the curve. Special examples are: the degree of curvature in all parts of the circle is the same, so the radius of curvature is the radius of the circle; the straight line is not curved, and the straight line is at that point. The radius of the tangent circle can be arbitrarily large, so the curvature is 0, so the straight line has no radius of curvature, or the radius of curvature is infinite.

can also be understood like this: the curve is differentiated as much as possible until it is finally approximated as an arc, and the radius corresponding to this arc is the radius of curvature of the point on the curve.