How long is the objection period of the invention patent? From when to when? Is it the same as the announcement period?

There is no objection period for invention patents. Similarly, there is no objection period for the other two patents, utility model and design. The objection period is for trademark applications.

Similar to objections, all three patents have invalidation stages.

For patents that have been authorized, whether inventions, utility models or designs, as long as they are in the stage of enjoying the patent right (for example, patents that are still in the protection period) or already enjoy the patent right (for example, patents that were previously authorized but later abandoned without paying), you can file a request for invalidation.

It should be noted that the term of protection of invention patents is 20 years, and that of utility model and design patents is 10 years, both from the date of application.