After patent has been issued does it have be prototyped and get into production phase.

The patent office breaks "invention" into two steps: conception of the idea for the invention, and reduction of the idea to practice. The former is that "Eureka" moment when you first conceive of the general idea in your head. The second is when all the pieces fall into place and the invention is, at least in theory, complete.

There are two ways one can achieve the "reduction to practice" step. You can have "actual reduction to practice", which means you have a working invention in your hands and it does what you thought it would do. The second way is called "constructive reduction to practice". This is usually achieved by showing that you've got all the steps to making your invention nailed down in such a way that anyone with a basic understanding of the subject matter can pick up your description and perform the steps and get your invention out of it. This is usually a written description of how the invention works, and is a necessary part of your patent application.

In the US, all you need to get patent rights for your patentable invention is to have gone through these two steps. You don't strictly need a prototype or investors or even ever have to make or use your invention. You get your rights solely based on having been the first person to conceive of it and describe it to the public. If your patent application is approved, you have all rights of a patent holder, no matter whether you have a prototype or not.

Sometimes, if a patent examiner doesn't think the invention works the way you claim it does, they may ask for proof that the invention does what you claimed it does in your application. Prototypes come in handy in these situations, but unless you're claiming a truly bizarre invention that smacks of physical impossibility (think perpetual motion machine), it's unlikely that you'll be asked for one. The patent examiner will simply go through your application and your description of the invention in the application will show that you've constructively reduced the invention to practice.

The time it takes to get something on the market depends on a number of manufacturing concerns, and maybe licensing concerns that are really beyond the scope of this forum.

If I understand your question, you have a patent already but are concerned about what happens now if you have problems getting the product to market. A patent is a right to exclude other people from making, selling, etc, the patented item. Someone could start manufacturing what is in your patent, but you'd have the ability to take them to court. If someone makes patentable improvements to your invention, they could get a patent on those improvements but if selling the whole would infringe your patent, you could still take them to court or convince them to take a license.

After a patent issues, there are scheduled maintenance fees that need to be paid. If those are not paid, the patent becomes unenforceable.

There is no requirement that you prototype or manufacture the invention described in your patent. You can still enforce a patent without actually producing anything. In fact, entities that enforce patents but don't actually produce the invention themselves are politely known as non-practicing entities and pejoratively as patent-trolls.

http://en.wikipedia.org/wiki/Patent_troll

as explained earlier, you only need to pay periodic maintenance fees to the USPTO to keep you patent alive and enforceable.

Before we can talk about an "issued" patent, let's be sure we're on the same page by discussing the steps that would need to have been gone through to get this far. First I assume we are talking about a U.S. patent, as each patent-granting jurisdiction has its own set of rules. In the U.S. a patent application would be written, describing the invention, illustrating it with drawings if possible, and containing a set of numbered "claims," each reciting an aspect of the invention to be protected by the patent. The patent application would be filed at the U.S. Patent & Trademark Office ("PTO") along with a government fee. Typically, after 18 months it would be PUBLISHED online by the PTO. Such a publication would not be the formal "issuance" of a patent that we are considering here. The number assigned to the published application would start with the year of publication, such as 2009 and then be followed by some other numbers and then a code such as A1 identifying it as a patent application publication. For example, US 2009/0181157 A1 refers to an application published July 16, 2009 for a method of attaching an antimicrobial substance to a surface.

After many months, these days typically two to three or more years from filing, a Patent Examiner would review the application and compare each of the claims with known technology (which we call the "prior art). Usually some or all of the claims would be initially found not to meet the legal standards for patentability and would be "rejected." The applicant would then respond by canceling the rejected claims and accepting the remaining ones, or more often, by amending the rejected claims and explaining why the wording so amended meets the legal tests. That process might be repeated until the Examiner agrees that all of the claims as amended re allowable under the law, or until the applicant gives up.

After the applicant receives a Notice of Allowance from the Examiner, he must pay an Issue Fee within three months. Then the PTO proceeds to generate a printed version of the patent and to assign to it a seven-digit patent number, followed by a code beginning with the letter B (indicating an issued patent). An example would be U.S. Patent 7,577,260 B2, issued August 18, 2009, for a method and apparatus to direct sound via steerable sonic antennae.

After the patent with a seven-digit patent number followed by a B2 (or sometimes B1) code has been ISSUED, then there isn't anything more that needs to be done to keep the patent alive ... until the first maintenance is due at 3 1/2 years from the date of issue. This is different from most foreign countries which require maintenance fees to be paid annually. (Indeed, such maintenance fees are often referred to as "annuities.")

There is no requirement under U.S. law that the owner of a patent manufacture the invention or make it available commercially.

This differs from the patent law of many other countries, which require that a patent be "worked" in that country within a period of time from patent grant. In those countries, the typical disability that stems from not "working" the patent is that a company in that country would then have the right to obtain a compulsory license to practice the patent, generally subject to a reasonable royalty as determined under the law of that country.

In the U.S., we do not have a law that gives a third party a compulsory license if the owner of the patent fails to "work" it within a given period. However, in 2006, the Supreme Court conferred upon us a principle that comes pretty close. The Court held that the court had discretion NOT to grant an injunction requested by a patent owner, here MercExchange, against an infringer, here eBay, unless the owner shows that it has (1)suffered irreparable injury,(2)no adequate remedy at law,(3)a balance of hardships in its favor,(4)the public interest would be served. Otherwise, money damages much like a foreign compulsory license.