PCT International Search and Preliminary Examination Guidelines
5.20 Claims should be interpreted the same way for both search and examination purposes. Each claim should be read giving the words the ordinary meaning and scope which would be attributed to them by a person skilled in the relevant art, unless in particular cases the description gives the words a special meaning, by explicit definition or otherwise. See the appendix to this chapter for further guidance with regard to the interpretation of claims.
5.21 A claim to a substance or composition for a particular use should generally be construed as meaning a substance or composition which is in fact suitable for the stated use; a known product which prima facie is the same as the substance or composition defined in the claim, but which is in a form which would render it unsuitable for the stated use, would not deprive the claim of novelty, but if the known product is in a form in which it is in fact suitable for the stated use, though it has never been described for that use, it would deprive the claim of novelty. For example, a claim to a known substance or composition for the first use in surgical, therapeutic and/or diagnostic methods that is presented in a form such as: “substance or composition X” followed by the indication of the use, for instance “... for use as a medicament”, “... as an antibacterial agent” or “... for curing disease Y” will be regarded as restricted to the substance or composition when presented or packaged for the use. See also paragraph 5.22. See the appendix to this chapter for further guidance with respect to use claims, and for an explanation of when an Authority may regard a “use” claim as equivalent to a “process” claim.
5.22 The effect of the preamble on the evaluation of the elements of a claim for search and examination purposes should be determined on a case by case basis in light of the facts in each case. During search and examination, statements in the preamble reciting the purpose or intended use of the claimed invention must be evaluated to determine whether the recited purpose or intended use results in a structural difference (or, in the case of process claims, a difference in process steps) between the claimed invention and the prior art. If so, the recitation serves to limit the claim. In two-part claims as defined in Rule 6.3(b), the preamble is regarded as a limitation on the scope of the claim.
5.23 If a claim commences with such words as “Apparatus for carrying out the process, etc., ...” this must be construed as meaning merely apparatus suitable for carrying out the process. An apparatus which otherwise possesses all of the features specified in the claim, but which would be unsuitable for the stated purpose or which would require modification to enable it to be so used, should not normally be considered as coming within the scope of the claim. For example, a claim recites a machine for cutting meat comprising apparatus limitations. The claim language “machine for cutting meat” sets forth only the function of the apparatus (that is, for cutting meat) without any positive structural limitations. Such language would not be given any weight in assessing novelty and inventive step as long as the prior art cutting machine was capable of cutting meat. In this case, one should treat the words “for cutting meat” merely as limitation to a machine adapted to cut meat. Thus, one would look to the prior art to see whether the cutting machine would be inherently capable of cutting the meat, whether or not the prior art description specified what material is cut by the machine. Similar considerations apply to a claim for a product for a particular use. For example, if a claim refers to “mold for molten steel,” this implies certain limitations for the mold. Therefore, a plastic ice cube tray with a melting point much lower than that of steel would not come within the claim. Similarly, a claim to a substance or composition for a particular use should be construed as meaning a substance or composition which is in fact suitable for the stated use; a known product which is per se the same as the substance or composition defined in the claim, but which is in a form which would render it unsuitable for the stated use, would not deprive the claim of novelty.
Open and Closed Claims
5.24 In evaluating novelty or inventive step, the examiner should consider which type of the transition phrase, such as “consisting of,” “comprising,” “characterized by,” or “consisting essentially of” is used in the claims. The subject matter to be searched depends on the type of transition phrase used.
(a) Where a claim is drafted using a “closed” type of transition phrase, the claim cannot be construed as including products or processes that include structural elements or process steps other than those set forth in the claim. For example, if a claim recites “a product consisting only of A, B and C,” it cannot be construed as including, and is novel over, prior art that discloses a product having A, B, C and D, or any other additional feature or elements. The phrase “consisting of” may be interpreted by some Authorities as a “closed” type of transition phrase, however, other Authorities treat such language as equivalent to “consisting essentially of” as noted in (c) below.
(b) Where a claim is drafted using an “open” type of transition phrase, it can be construed as including products or processes that include non-recited components or process steps, respectively. For example, if a claim recites “a product comprising A, B and C,” it can be construed as including, and lacks novelty over, prior art that discloses a product having A, B, C and D, as well as any additional feature or element.
(c) Where a claim is drafted using “consisting essentially of” as the transition phrase, the claim occupies a middle ground between closed claims that are written in a closed format and fully open claims. The transitional phrase “consisting essentially of” limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. For the purposes of search and examination, absent a clear indication in the description or claims of what the basic and novel characteristics actually are, “consisting essentially of” will be construed as equivalent to open (for example, “comprising”) language.
5.25 Where a limitation in the claim defines a means or a step in terms of its function or characteristics without specifying the structure or material or act in support thereof, such a limitation should be construed as defining any structure or material or act which is capable of performing the defined function or which has the defined characteristics, unless the means are further specified in the claim. If the means are further specified, the claim would be interpreted to include those further specified limitations. For example, if a claim recites valve means for restricting the flow of fluid, it would be interpreted by the examiner to include the further specified limitation of a valve means rather than any means for restricting flow of fluid. As another example, a claim aimed at “a building material incorporating a layer which insulates heat” should be interpreted as a building material incorporating any “product” that is “a layer which insulates heat.” It should be noted, however, that the issues of whether such means-plus-function claims are clear and concise or not and whether the disclosure of the claimed invention is sufficient for a person skilled in the art or not should be determined separately.
5.26 Where a claim defines a product in terms of the process by which the product is made, the claim as a whole is directed to a product. Such a claim lacks novelty if a prior art product, even if made by an undisclosed process, appears to be inherently the same as, or indistinguishable from, the claimed invention. See the appendix to this chapter for more guidance with respect to product by process claims.
5.27 Where a product can only be defined by the process steps by which the product is made, or where the manufacturing process would be expected to impart distinctive characteristics on the final product, the examiner would consider the process steps in determining the subject of the search and assessing patentability over the prior art. For example, a claim recites “a two-layer structured panel which is made by welding together an iron sub-panel and a nickel sub-panel.” In this case, the process of “welding” would be considered by the examiner in determining the subject of the search and in assessing patentability over the prior art since the process of welding produces physical properties in the end product which are different from those produced by processes other than welding; that is, the product can only be defined by the process step. Novelty of the claim is not brought into question unless an identical two-layer structural panel made by means of welding is discovered in the prior art.
Product and Apparatus Limitations in Process Claims
5.28 Product and apparatus limitations that appear in process claims must be taken into account for search and examination purposes. See paragraph 5.22 for the effect of the preamble on claim interpretation.