Sufficiency of Disclosure

1Section 10 stipulates the description of an invention as a positive requirement for the grant of a patent. Section 64(1)(h) mentions similar features, the absence of which can be a ground of revocation. There are subtle differences in the terminology used in both the sections. In s 64(1)(h), the words 'sufficiently and fairly' qualify the phrase 'describe the invention and the method by which it is to be performed'; whereas, in s 10(4)(a) it is stated that the complete specification shall 'fully and particularly describe the invention … and the method by which it is to be performed'. The comparative ground of opposition in ss 25(1)(g) and 25(2)(g) uses the phrase 'sufficiently and clearly describe the invention or the method by which it is to be performed'.

2Section 64(1)(h) provides for a combination of grounds on which a patent may be revoked by a person interested in the patent. It pertains to the concept of sufficiency of description in the complete specification. From a bare reading of ground (h), the following two aspects of insufficiency emerge for consideration.

(a) The description of the working of the invention in the complete specification is not sufficient to enable a 'person in India possessing average skill in, and average knowledge of, the art to which the invention relates', to 'work the invention' ie, description not sufficient to work the invention (insufficiency of description). (b) The complete specification does not 'disclose the best method' of performing the invention known to the applicant for which he was entitled to claim protection, ie the applicant does not disclose the best method despite having knowledge of the same (non-disclosure of best method).

3Insufficiency of description has two defining elements. First, it requires that the complete specification must describe the invention claimed in such a way that the description must be sufficient to enable a person skilled in the art to work the invention without making any further invention. Secondly, such description must be fair so that it is not difficult to follow. In Farbwerke Hoechst v Unichem Laboratories (1968) (p 64) the Bombay High Court held that "the claim need only be as clear as the subject admits, and that a patentee need not so simplify his claim as to make it easy for infringers to evade it". These two requirements are enumerated in great detail in Edison & Swan Electric v Holland: ((1889) 6 RPC 243, pp 279-80.)

The first condition imposes upon the patentee the necessity of stating in clear and intelligible language what his invention really is, so that others may know what addition the patentee has made to what was known before, so that they may know what are not at liberty to do without his consent during the existence of the patent; in other words, so that they may know what the monopoly is that is granted to the patentee…The second condition imposes upon the patentee the necessity of stating in clear and intelligible language, in what manner the patented invention is to be performed: so that others may learn from the specification how practically to avail themselves to the patented invention when the patent has expired; how they are to do what is necessary to carry out the new invention, the nature of which has been previously described.

4It is important to note that the terms 'describe' (which includes its noun 'description') and 'disclosure' have been used interchangeably. Section 10(4)(a) of the Patents Act requires that every complete specification shall 'fully and particularly' describe the invention and its operation or use. But, on the same subject matter of description, s 64(1)(h) states that a patent may be revoked if the complete specification does not 'sufficiently and fairly' describe the invention. The words 'fully and particularly' and 'sufficiently and fairly' are analogous to the words 'clear enough and complete enough' used in the UK Patents Act. (UK Patents Act 1977, s 14(3).) Article 83 of the EPC uses the word 'sufficient' disclosure, which conveys a similar idea as used in the Patents Act.

5Whether the complete specification sufficiently and fairly describes the invention and the method of its performance is a matter that will depend on the construction of the patent. The sufficiency of a claim has to be decided with regard to the width of the claim. If the claims are broad, indeterminate and of a speculative character, they may be revoked under the above ground. (See Eastman Kodak Co's Application [1970] FSR 393, pp 401-2, (1970) RPC 548; Shell Development Co's Application (1947) 64 RPC 151.)

6Claims may be phrased widely and may contain terms which do not have definite meaning. The purpose of a patent specification is to disclose how an alleged invention in its full width may be put into practice, and not to enable that width to be adjustable as subsequent practice develops. (See Pottier's Application (1967) RPC 170, p 172.) Though the mere width of a claim cannot be a ground for raising an objection of insufficiency, it is a fundamental rule of patent law that the consideration which a patentee gives for his monopoly is the disclosure which he makes and the protection which he gets cannot extend further than is necessary to protect that which, in view of his disclosure, he is fairly entitled to cover.

7The claim has to define the monopoly clearly to prevent intrusion into it so that a producer can know where he cannot intrude. (See Proctor & Gamble Co v Peaudouce (UK) Ltd [1989] 1 FSR 180, p 198 (CA).) If it is not possible for the producer to know whether his product would infringe a claim, such a claim may be said to be insufficiently described.

8One object of patent law is to ensure that the information disclosed in a patent is of such nature that it enables a person skilled in the art to repeat it. The patent should disclose the method by which it is to be performed. The description of the method or the instructions for the working of the invention should be self-contained. They should, by themselves, be sufficient to enable a person in India possessing average skill and knowledge of the art to work the invention. (Patents Act 1970, s 64(1)(h).)

9The information disclosed should be workable. In cases where the claims include a number of discrete methods or products, the patentee must enable the invention to be performed in respect of each of them. (See Biogen Inc v Medeva Plc (1997) RPC 1, p 48, per Lord Hoffmann.) A patent can be revoked if this requirement is not met. In deciding whether the invention has been adequately disclosed, the date of filing of the application will be relevant.

10For a patent to be revoked for not sufficiently and fairly describing the invention, it is not enough to state that the claim was broad and hence the disclosure was not sufficient. (See T19/90 Harvard/Onco-mouse [1991] EPOR 525 (Exam Div).) The British courts have evolved a set of factors that will determine whether an invention has been disclosed in a manner that is clear enough and complete enough. These factors have been incorporated in the Patents Act and will apply in determining whether an invention has been sufficiently and fairly described. (Patents Act 1970, ss 10(4)(a) and 64(1)(h).)

11The reference to a 'person of average skill and knowledge of the art' in s 65(1)(h) is a deliberate departure from the concept of 'a person skilled in the art.' (The phrase 'person skilled in the art' appears in s 2(1)(ja) in the context of inventive step.) While the former is used to evaluate sufficiency of disclosure, the latter is used for the purpose of evaluating inventive step. Though the notional skilled addressee should be the same person or team for determining obviousness and sufficiency of an invention, they differ in one significant aspect. (See Halliburton Energy Services Inc v Smith International (North Sea) Ltd [2006] EWCA Civ 1715, para 22 (CA).) The 'person skilled in the art' is expected to have knowledge only of the prior art but the 'person of average skill and knowledge of the art' is expected to have knowledge of prior art and of the invention as disclosed. (See T694/92 Mycogen/Modifying Plant Cells [1998] EPOR 114, p 120.) In determining whether the invention is sufficiently and fairly disclosed, the said person should be able to work the invention with the knowledge disclosed.

12Moreover, the Patents Act requires such a person to be based in India. Such a person is not expected to perform any inventive step in working the invention. What is expected of such a person is 'reasonable degree of skill and common knowledge in making trials and to correct obvious errors in the specification if a means of correcting them can readily be found'. (Valensi v British Radio Corpn [1972] FSR 273, p 310, (1973) RPC 337 (CA), per Buckley LJ. See also Mentor Corpn v Hollister Inc (1993) RPC 7, p 13 (CA).)

13The level of disclosure contemplated is one that sufficiently enables a person of average skill and knowledge to work the invention. In the case of an invention which discloses a principle capable of general application, the claims may be in correspondingly general terms, and the patentee need not show that he has proved its application in every individual instance. But, if the claims include a number of discrete methods or products, the patentee must enable the invention to be performed in respect of each of them. (See Biogen Inc v Medeva Plc (1997) RPC 1, p 48.) Thus where the patentee disclosed a 'beneficial property which is common to the class, he will be entitled to a patent for all products of that class (assuming them to be new) even though he has not himself made more than one or two of them'. (Ibid, p 49.) "A claim disclosing a general principle would be granted and treated as sufficient disclosure if the general principle would work equally well for specific classes." (See T292/85 Genentech/Polypeptide Expression [1989] EPOR 1.) But if the patentee is not able to demonstrate a common principle by which the effect will be shared by other products of the same class, no patent will be granted for that class even if some members of the class may have the same beneficial effect. (See May & Baker Ltd v Boots Pure Drug Co Ltd (1950) 67 RPC 23, p 50; Biogen Inc v Medeva Plc (1997) RPC 1, p 49.)

14The extent to which the disclosure should be sufficient to work the invention will depend on various factors. In the United Kingdom, the related concept of clarity needed for the invention to be performed depends on nature of the invention and circumstances of the case. The courts have devised concepts to define the extent of disclosure, such as 'enabling disclosure' to explain the standard of disclosure. As the patent is addressed to a person of average skill and knowledge of the art, it follows that the patent need not disclose what is self-evident. The skilled person may have to use his skill to perform the invention. (See Mentor Corpn v Hollister (1993) RPC 7, p 12.) He may also have to use the common general knowledge and correct obvious mistakes in the specification. (Valensi v British Radio Corpn [1972] FSR 273, p 310, (1973) RPC 337 (CA), per Buckley LJ. See also Mentor Corpn v Hollister Inc (1993) RPC 7, p 13 (CA).)

15The complete specification should sufficiently and fairly describe the method by which the invention is to be performed. Issues have been raised with regard to the extent to which an invention needs to be performed for the disclosure to be sufficient. Such issues arise where the patent consists of an application of a theoretical principle or a chemical formula or a class of substances. Inventions employing principles of organic chemistry will try to claim a broad range of products by citing a representative formula which can be substituted with similar substances. In some earlier decisions, the courts have held that it is not necessary for the complete specification to set out every detail necessary for performance, but can leave it to the skilled person to use his skills to perform the invention. (See Mölnlycke AB v Proctor & Gamble Ltd [1992] FSR 549, p 600.) "But the House of Lords rejected the earlier approach and held that specification must enable the invention to be performed to the full extent of the monopoly claimed. (Biogen Inc v Medeva Plc (1997) RPC 1, p 48. See also Evans Medical Ltd's Patent (1998) RPC 517, p 562.)

16Claim without an enabling disclosure cannot be sustained, according to the Division Bench of the Delhi High Court. In Merck Sharp and Dohme v Glenmark Pharmaceuticals (2015) (para 46), the Court held that enabling a person of ordinary skill to work the invention as a quid pro quo for the grant of the monopoly.