Final answer:
Tesla's exact announcement date to open its patents is not specified in the reference provided, but it represents a modern stance on the historic issue of patents in the realm of business and technology.
Step-by-step explanation:
The specifics regarding Tesla's announcement to open its patents have not been provided in the reference information given. However, historically speaking, the issue of patents and their open or restricted use has been a significant topic in the business and technology communities. Notable historical figures like Thomas Edison and Eli Whitney faced challenges related to their patents, which shows how this issue has long been a part of the innovation landscape.
For instance, Tesla's move to open its patents reflects a modern approach to this historic issue, offering an interesting comparison to Edison's and Whitney's experiences where financial rewards or patent rights were not always in line with the social benefits of their inventions.