Difference between Invention and Optimization

Recently, I was a part of Systematic Creativity and TRIZ Basics online class presented by professor Leonid Chechurin from LUT. One of the first questions in the class was to give our own definition of the difference between the invention and optimization. I found it quite interesting especially given the fact that I never thought of that.  The result of my reflections are below.

Optimization – gradual change of an existing system, process or solution by upgrading or downgrading existing properties to a new optimum or, in other words, to a new expected outcome. Thus, optimization is the process of reaching a new optimum or a new balance of interests.

Invention is the process of reaching another level of novelty. Invention is a gradual or radical change of the existing solution by adding, upgrading or downgrading the existing properties until a new nonexistent level of problem resolution is found. Novelty is the distinguishing factor between these two.

These processes are different, thus, call for different mindset, expected result and tools.

What would you say about this definitions? How do you define optimization and invention?