Convex Mirror:

The convex mirror reflects light rays in such a manner that the effect is alike to that of a concave lens. The incident rays, if parallel, are spread out (as shown in figure below) after they are reflected from the surface. The converging incident rays, when the angle of convergence is just correct, are collimated by a convex mirror (as shown in figure below). Whenever you look at the reflection of a scene in a convex mirror, the objects all emerge decreased. The field of visualization is enlarged, a fact which is used to benefit in some automotive rear-view mirrors.

Figure: (a) A convex mirror spreads parallel incident light rays. (b) The similar mirror collimates converging incident light rays.

The level to which a convex mirror spreads light rays based on the radius of curvature. The lesser the radius of curvature, the greater is the extent to which the parallel incident rays diverge after reflection.