Each patent is for 1 invention only. The later patent is called a divisional. Typically the description is identical for such patents or applications. Both may have the same description but protect different scope of invention. If you look at claim 1 for both patents you will see the differences 

Each patent is for 1 invention only. The later patent is called a divisional. Typically the description is identical for such patents or applications. Both may have the same description but protect different scope of invention. If you look at claim 1 for both patents you will see the differences 

Hi Mahdi,

Patent 6225066 is a continuation of the patent 6300061. (Please refer to the USPTO glossary in the following link to understand what are continuation, divisional and continuation-in-part applications: https://www.uspto.gov/main/glossary/)

A continuation application is filed when you have filed for a patent with a set of claims protecting an invention and then you want to add some more claims for the same invention at a later stage. The continuation application however has to be filed before the earlier application is either abandoned or patented. In the example you have given, if you notice, the continuation patent 6225066 is filed (October 25, 1999) before the grant of the earlier patent 6300061 (October 9, 2001). The title & inventors therefore are same since both the patents are by same inventors and refer to same invention (determining whether a bacterial strain is resistant to a drug) as rightly pointed out by Eugene.

The patents however differ technically in the procedure used for determining whether a bacterial strain is resistant to a drug (See the differences in the set of claims in both the patents). The main difference lies in the order in which the three entities - 'bacterial strain', 'mycobacteriophage' and 'drug' are incubated. In the first patent - 6300061, first 'bacterial strain' is incubated with 'mycobacteriophage' to form 'mycobacterial lysogens' which is then incubated with 'drug'. There are two steps here as I understand (Please refer Claim 1(a) in the patent 6300061). In the continuation patent 6225066, the inventors have added more claims for a slightly different procedure in addition to the one claimed in the patent 6300061. The newly added claims refer to the procedure in which all the three elements are incubated together in a single step and tested (Please refer Claim 1(a) in 6300061).

Hi Mahdi

Fencing of a property is very important which determines the scope.

In the same way patent scope is defined by the claims and not by its title. Hence same title does not means the same subject matter is being claimed.

The above answers are each mostly correct.  The simple answer is that under the Federal Rules, the only requirements a patent title must meet are that it be short and specific.  It is therefore common for a patent attorney or agent to name related or similar patents the same title.   

Hello Mahdi,

Your observation of equal titles and different patent numbers is very interesting for people outside the intellectual property field. We are very welcome to explain why!

When we study about intellectual property, especially about patents, we see that scientific articles must have different titles and they are not the same.

When we talk about title of the patent they can be exactly the same without any problem, the differential is in what is being required, I suggest you to take a kind look at the claims.

Almost all explained the matter in right ways.

A part of comment of Madam Sheila - ".............title of the patent they can be exactly the same without any problem, the differential is in what is being required, I suggest you to take a kind look at the claims". In brief, this could be the conclusion.

Regards