What is the purpose of a patent specification?
The specification of a patent serves a different purpose than that of the claims. Whereas the claims define the legal scope of protection, the patent specification describes the invention and provides support for the claims. In a utility patent, the specification includes the drawings and the written description excluding the claims. The primary section of the specification is the Detailed Description of the Preferred Embodiments which describes the invention in (hopefully) gory detail with frequent references to the numbered parts in the drawings, or “Figures.” Keep in mind that the specification generally does not limit the claims, but rather provides examples of the inventive concept.
A secondary purpose of a specification is more defensive in nature. The typical patent specification often contains details that never end up in the claims. Those details, even if unclaimed, can block future patent applications from getting allowed. Examiners can rely on any portion of a published specification that discusses a particular feature to reject claims in subsequent applications.
Why must claim amendments find support in the specification?
There is a rigid rule in patent prosecution that is strictly enforced: you can only claim what is disclosed in the specification. You cannot claim what is not disclosed [see 35 USC 112(a)]. Therefore, the specification must adequately disclose the invention so as to support any particular features recited in the claims.
This means that in responding to an Office Action, you can amend the claims to add only those features adequately supported by the specification [see MPEP Section 2163].
Can the specification be revised in order to support claim amendments?
What if a feature is arguably disclosed in the specification? Can the applicant further amend the specification to provide greater support for the claim amendments?
This can be a tricky feat to accomplish, but it might be possible to amend the specification to clarify a feature that was originally disclosed. For example, suppose a figure illustrates a feature while the written specification stated little or nothing about the illustrated feature. One possibility may be to amend the written specification to clarify such a feature that was originally drawn.
A new drawing will generally be considered new matter. Revising the written specification, however, might not be considered new matter depending upon how the added text compares to the original disclosure (i.e., Is the added text a clarification or an addition?).
What should you do if your claim amendments are not supported by the specification?
If the specification altogether fails to disclose features you want to claim, it may be necessary to file a continuation-in-part (CIP) application to add new subject matter.
The drawback of a CIP is that the newly added matter will not get the priority date of the parent application. Instead, the newly added subject matter gets the later filing date of the CIP application itself. This opens the door for additional prior art to be cited against your CIP application (i.e., those prior art references with priority dates in between your priority date and the filing date of your CIP application).
Another option may be carefully word the claim amendments such that they find support in the specification. How much flexibility is available for use in the claim language will depend the level of disclosure in the specification.
Hindsight is perfect, but foresight is even better
Hindsight is always perfect. It’s easy to look back and see what should have been done in the first place. The problem with hindsight is that it is impermissible in patent applications. The patent application process can be brutally unforgiving when it comes to the lack of disclosure.
On the other hand, foresight is prudent and useful. Since an applicant cannot predict how a patent examiner will reject the patent claims, it pays to have a thorough and well-detailed specification that sufficiently discloses all claimable features. This leaves the applicant with flexibility and options when it comes to responding to Office Actions.
Many things are unknown at the initial filing of a non-provisional application. You don’t know what prior art references the examiner will find or how the examiner will interpret your claim terms. The uncertainty surrounding the utility patent application process makes it critical to submit a thoroughly detailed specification at the very beginning. Otherwise, you might pay a heavy price that goes beyond the financial cost of the patent filing.