Is academia right approach in order to implement an idea presented in my MSc Thesis? On my Master's I had an idea and made the following thesis proposing an new idea in order to offer a more user-friendly Privacy Enchanhing Technology, https://is.gd/YUUFLE . 

Hence, in order to implement it, I decided to use it as a basis for a PhD in Japan via a MEXT scholarship. (I also do Japaneese language lessons as well to mitigate any language barrier as well.) But still I have this question:

Is good idea to use the academia and academic environment as a "tool" in order to implement the idea? 

In other words instead of making a company that is a financially risky approach, in order to implement the idea of my master thesis, I thought an academic environment is more free-to-express to do so. Also I will consider the project sucessfull if I manage to make the average Joe to use it instead for making a profit of it (but I need some wage as well).

So having said that how do I approach an future supervisor and how I can make my supervisor also a "colaborator" in the project as well? Would just by saying that I have an idea would make any future supervisor unwilling to acept me for a PhD?
I think the very first thing you have to do is outline what time, skills, personnel and money is necessary to realize your idea. What is the technology readiness level you have achieved so far? At which point would you need industry help to develop the product? High-technology product development can easily take 5-10 years from lab idea to a certified product. A university/PhD is not a money source for a undefined part of a bigger project in its self-understanding.

For a PhD you have to publish and technical optimizations are not the scope of most journals. Could you publish single development steps? This is something you have to ask and plan with a possible supervisor.

Sometimes this is a good idea, especially as there are many funding sources for academia to develop and realize ideas together with industry and industry often has not the time/skills to write proposals. But also then, the PhD students often have to submit a project plan of their future PhD work, they get paid for working on working packages of the industry project and have to find and outline work separated (best case related to reduce work load) from these working packages to write a PhD thesis with scientific results rather than technical optimizations.

I just got funded such a project based on results of my master and PhD work and a following idea, identified possible university and industry partners, wrote proposal etc, got funded (overall 6-12 months minimum till money is available/project start)