Henry Ford come up with assembly line for car production. Japan perfected this idea by introducing their own individual innovations/changes/improvements. Many people are creative but they're not innovate enough to create their creations practical. Innovation makes creativity practical and efficient. Most inventors fail because they are not innovative enough. Most painters are creative but when they introduce innovation inside their creation/art they become artists. Without creativity there isn't any product/concept that needs implementation as soon as new things is believed up it needs innovation. Development and research is all about innovation. Sometimes innovation can lead to a realization from the creation being impractical and so this new creative idea could be abandoned along with a new creative idea may be born thus innovation can lead to creativity. Innovation is giving a new direction to a existing idea.
There's confusion and fuzziness between creativity and innovation because indeed innovation is approximately creating new methods to implement the existing/created concept. Thus they both have creativity inside them. Innovation also involves elements of creativity.
All PhD classes are for researching innovative ways of doing that old stuff in better plus more efficient ways. Innovation is all about solving existing problems. With a deeper level innovation is research. In the research institutes they may be creating better and better innovations for existing solutions. You don't demand a PhD for creativity however for innovation on the cutting edge highest level a PhD is nearly a vital requirement. In fact in the university level innovation is preferred over creativity. For almost any newly created ideas are doubted till they may be scientifically defined, measured and tested and also this involves complex and time consuming investigations as well as finances. However whatever is already being used and possesses proved its utility then any improvement through innovation is accepted whole heartedly. My own, personal invention, 'Vacuum power generators' is based on an audio principle that, 'nature abhors a vacuum'; nonetheless it was rejected on the highest levels of the US government due to another sound principle 'The law of conservation of energy'. What the law states of conservation of your energy claims that the energy you put in will give back less because of friction. However in nature you will find exceptions to this law! Hydrolic pressure, fulcrum power all give back more energy then they take in. And vacuum power may be the fulcrum of wind power. But it's an unproven and too radical a concept as well as requires a small fortune to create a proto type. However my little innovation of tweaking just a little improvement within the baby milk bottle I had been able to sell right away.
Creativity is essential for innovation for a product must exist at least in the concept stage to suit your needs cannot innovate whatever doesn't exist. Thus innovation depends upon creativity while creativity doesn't depend on innovation. Though the better success of creativity is dependent upon innovation.