Patent Claim Drafting 101
A simple guide to drafting an independent claim
We introduce a common type of independent claim and go through an example of how to draft just such an independent claim.
Anatomy of an independent claim
There are many styles of patent claim. Here is generic example of a modern style independent claim commonly used in the mechanical and electrical arts.
1. A class, comprising:
a element for function;
a element connection the element above for function;
a element connection the element above for function; and
a element connection the element above for function.
A class is the general category of apparatus you've invented. Use generic language. Class can be as broad as you like (e.g., "apparatus") or as narrow as you like (e.g., "remote control for high-definition optical disc players."). Whatever you write here will generally provide the boundaries for the examiner's patentability search and will consequently limit which products your claim will cover. For example, it is difficult to argue that a CD player's remote control would infringe a claim written with the narrow optical disc example above. However, it would be straightforward to make this argument if we simply said "remote control." Many claim drafters delve into the latest US or International classification schedules and use the same language used there.
An element is one of the structural elements that make up your invention. Structural elements are physical, such as components, parts, and pieces, but they can also be non-physical, such as holes, images, and light rays. Structural elements are things that can be quickly nailed down by looking at a product. Structural elements are nouns, such as housing, button, screen, infrared beam, and air gap. Elements are always introduced with an indefinite article, such as "a". How many elements are required in a patent claim? As many as required to be whatever you said it is (as defined by your class) and provide novelty and non-obviousness over the prior art. Ideally, you want to use as few elements as you can, since this will give you broader coverage.
An element above denotes an element that has already been introduced in the claim. In the above generic claim, we have three elements and two of them are talked about again as indicated with element above. Because of this, we use the definite article "the" in referring to the element above.
A connection is language that connects a element to an element above that has already been mentioned in the claim. connections can be structural themselves or less so. Verb phrases are usually used. For example, "connected to" or "bolted to" are physical and easily seen in a product. On the other hand, "in wireless communication with" is an example of a not-so-structural . In a well written claim, all elements are interconnected via connections – there are no loose ends or orphan elements hanging out in space. Connection language can be as broad as you like (e.g., "coupled to") or as narrow as you like (e.g., "responsive to a pulsed signal from the").
A function is language describing the function of the element or its interaction with the connected through the connection. is typically optional, but certainly helps clarify the claim. Well drafted functions don't limit the claim, rather, they promote understanding of the claim. If a wheel (element) is pinned (connection) to an axle (element above), then it hardly hurts to say that the wheel is for rotating about the axle (function). However, you wouldn't want to say the wheel is for rotating along pavement, as this may unduly limit your claim to an all purpose vehicle for travelling on paved roads only.
A note about novelty and non-obviousness. It's very likely that all of your elements are known and not patentable in themselves. It's the combination of elements as defined by their s that is what will be patentably. plays a role too, but every function should be tied to at least one underlying element. If you have an element that you think it patentable in its own right, then you should consider writing a claim for that element alone. Such a claim would be usually broader and could be presented in the same patent application, a continuation or divisional application, or an entirely separate patent application.
Drafting an independent claim
Now let's do an example. Suppose I've invented a new kind of remote control for a high-definition DVD player. Here's how I would draft an independent claim.
class = remote control for media playback
I want broad coverage, and I don't think any kind of remote control (TV, CD player, etc) has seen this improvement before. On the other hand, I don't want the examiner to dig up model airplane remote controls and use those against me, which might happen if I simply said "remote control".
element = housing
This is a good one to start with because it gives me a place to put everything else. Claim drafting made easier when you begin with a housing, frame, semiconductor substrate, or other large, essential element.
element = dial
Dials exist in the prior art, but has anyone ever put one on a remote control before? I hope not because this is my invention. I may have more than one dial, but the minimum require would be one, so this is why I say "a". Had I needed two, I would say "a plurality of dials."
element = circuit
element = electromagnetic radiation source Note the generic language. This could be anything from a light bulb to a UV-emitting LED.
Inserting these into the claim template above, here is what I have so far:
1. A remote control for media playback, comprising:
a housing for function;
a dial connection the element above for ;
a circuit connection the for function; and
an electromagnetic radiation source connection the element_above for function.
Now what is the function of my housing? I suppose someone may operate a remote control with their toes, but I'll go out on a limb and say my is "being held in a user's hand."
Next, we need a connection for the dial. I could say that it's connected to the housing, but what if somebody connected their dial to something else, like the circuit? Lots of dials come with leads that get soldered to circuit boards. If I'm not careful, someone could enjoy the essence of my invention without infringing my claim. So instead I'll say that the dial is "rotatable with respect to" (connection) the "housing" (element above). There. As long as the dial can turn relative to the housing, I've covered it.
As for the function of the dial, I'll help readers out by saying that it's for "being turned by the user." After all a dial's no good unless it can be turned by someone.
Now we have to connect the circuit to something. I could put it inside the housing, but, as accurate as that may be, that doesn't tell us very much. Also, what if someone make a knock-off of my invention where a part of the circuit is outside the housing? That sounds unlikely now, but if my invention really takes off there will be engineers everywhere thinking about ways to design around my patent. Since I can't outsmart engineers I've never met, I'll avoid saying things that are not really necessary. On the other hand, if I say "electrically coupled to the dial" then I'm starting to build a meaningful picture of this thing. I'd like to see someone design around that. Thus, my connection for the circuit is "electrically coupled to" and this refers to the "dial" (element above).
So what does my circuit do? Well, if my remote control invention is going to be any use at all, it has to generate some kind of signal based on the dial position. That sounds like a good function right there. Let's go with "generating a signal based on a position of the dial." Note the indefinite articles. "Signal" and "position" are actually elements and must follow the same rule of introduction.
Almost done. All I need to do is get my signal from the circuit to the DVD player or other device. That's what the electromagnetic radiation source is for. So let's turn this function into claim language by saying "emitting electromagnetic radiation based on the signal generated by the circuit." Of course, I'll need to connect it to the circuit first, and I'll do this as broadly as possible by defining the connection as "electrically coupled to."
Done. Here is what my claim looks like:
1. A remote control for media playback, comprising:
a housing for being held in a user's hand;
a dial rotatable with respect to the housing for being turned by the user;
a circuit electrically coupled to the dial for generating a signal based on a position of the dial; and
an electromagnetic radiation source electrically coupled to the circuit for emitting electromagnetic radiation based on the signal generated by the circuit.
There you have it: a broadly drafted independent claim to a dial-based remote control.
Dependent claims – What about all those other features?
But surely my invention has more than one dial or at least has some buttons and other stuff. Yes, it does, but that does not belong in my independent claim. I've got the minimum number of elements required for a remote control. I've got something for the user to hold (the housing), I've got an input device (the dial), an output device (the electromagnetic radiation source), and something to convert the user's input into a signal that the DVD player can understand (the circuit). This simply wouldn't be remote control if we omitted one of these elements. I have just enough elements to control some basic function of the DVD player. Adding supplementary elements (buttons, lights, bells, whistles) would allow someone to avoid my claim by omitting them from their product, while still using the essence of my invention (the dial). Remember the patent claim mantra: less is more.
Supplementary elements belong in dependent claims.
