A common question (or variation) I get asked is "I have an idea that is based on that is based on a product that was patented at one point, how can I tell if the product is still patented so I don't infringe? "
Start-ups ask this question to 1) try to limit their liability even if they are modifying a product, 2) if the start-up is modifying a product they may have to get a license for the assignee of the patent to make their product , and it would be a much cheaper process without having to pay the license fees.
To answer this question, it is important to take a step back and understand the "life cycle" of a patent application. Upon filing an application, a patent is given an application number, these generally are in the form of XX / XXX, XXX. 18 months after the application is filed, the application will publish and be given a publication number in the form of XXXX / XXX, XXXX. Depending on what technology the invention is around 2-3 years after filing the application, the USPTO will look at the application and if the claimed invention is different than what is known a patent will be granted with a patent number in the form of USXXX, XXXX. If a patent has not granted for an invention, that start-up does not have any intellectual property which the can sue under.
Applications that are granted as patents may give the holder protection for 20 years from the date the application was filed. Accordingly, if a start-up filed an application on Jan 1, 2000 they can have intellectual property protection up until Jan 1, 2020, when the patent will expire. However, patents and applications themselves can expire or be abandoned before their full term expires.
Applications can become abandoned for various reasons. Typically, before an application becomes a granted patent, there will be several office actions (correspondences between the USPTO and an attorney). If the startup or attorney fails to respond to an office action, the application will become abandoned. Upon the patent office determining that a patent should be granted on a patent application, an "issue fee" must be paid. This issue fee is pretty steep $ 1,770 for large companies, $ 885 for small entities. Accordingly, after a 3-5 year period from initially filing the application, a startup may determine that the invention disclosed in the application is no longer profitable or may just not want to pay the fee. The application at this point will become abandoned without ever being granted.
If the start-up pays the issue fee the application is granted. However, a patent term MAY be 20 years. Maintenance fees must be paid for the patent at the 3.5 year mark after the patent is granted ($ 1,150), 7.5 year mark after the patent is granted ($ 2,900) and 11.5 year mark after the patent is granted ($ 4,810). As a note, these fees are reduced in half for small entities. Essentially, if a patent is not profitable at these marks, a start-up may decide not to pay the maintenance fee and let the patent go abandoned before the 20 year term expires.
So essentially the way to determine if a patent has expired is
1) Determine if the patent was filed, or claims priority to a patent filed prior to 20 years before the date.
2) Determine if the maintenance fees have been paid.
A good way to find out the filing date for a patent is to search Google.com/patents, find the patent, and look on the cover page of the patent.
To determine if the maintenance fees for a patent have been paid, inventors should go to the public pair portal at ( http://portal.uspto.gov/external/portal/pair/ ), type in the "captcha code." Then, select the "patent number" field and type in the patent number. This will bring you to the USPTO's transaction history of a patent (you can also look at this for other info about pending patent applications as well, and responses to the USPTO for the patents, so you can use this to look at Apple's newest patent applications ). In response to selecting the "transaction history" tab, you will be brought up to the history of the patent within the USPTO. If the maintenance fees have been paid then this will show up on the report, if they havnt been paid there should be an entry stating 'Expire Patent "which indicates that the patent has expired.