Disclosure of the invention

Enabling disclosure

5.114 The claims play an important role since they define the scope of the monopoly conferred by a patent. However, the grant of an exclusive monopoly to an applicant is in exchange for a full disclosure of the invention and how it may be worked. The importance of a sufficient disclosure and the consequences of insufficiency in revocation were discussed in Ng Kok Cheng v Chua Say Tiong [2001] SGHC 143, where the Court referred to the guidance provided by the UK decision of Biogen Inc. v Medeva plc [1997] RPC 1 at [47]:

“The requirement of an enabling disclosure in a patent specification is a matter of substance and not form. Its absence should therefore be a ground not only for refusal of the application but also for revocation of the patent after grant.”

5.115 The statutory requirements of proper disclosure are set out in Sections 25(4) and 25(5)(c), which requires that the description of the invention and its operation or use must be in such complete and clear terms as to enable any person skilled in the art or science of the invention or in the art closest to it, to make, construct, compound or use the invention.

5.116 Section 25(4) states that the application “shall disclose the invention in a manner which is clear and complete for the invention to be performed by a person skilled in the art”. This requirement was considered in Ng Kok Cheng v Chua Say Tiong [2001] SGHC 143 at [49], where the Court stated that:

“There is one small point here which I should dispose of before dealing with the defendant’s submissions on the merits. This relates to what level of description is required under ss 25(4) and 80(1)(c). The wording requires the specification to disclose the invention ‘clearly and completely’ for it to be performed.

The equivalent English wording is ‘clearly and completely enough’. Mr Kang submitted that the requirement of the UK Act is more lax and that the Singapore requirement is stricter so that the specification must be clear and complete. I do not agree. Although the word ‘enough’ does not appear in the Singapore provisions, the phrase ‘clear and complete’ is not an unqualified one in either of those sections. Instead, it is followed by the words ‘for it to be performed by a person skilled in the art’. This is a clear qualification implying that as long as a person skilled in the art would find the wording of the specification sufficient to enable him to make the invention, it does not matter that the specification does not state every single step that has to be followed in order to make the invention. Thus, the clear meaning of the legislation taken as a whole is that it is sufficient if the specification is clear enough and complete enough and absolute clarity and completeness are not required.”

5.117 Notably, the approach that absolute clarity and completeness are not required has been followed in First Currency Choice Pte Ltd v Main-Line Corporate Holdings Ltd [2007] SGCA 50 and Dien Ghin Electronic (S) Pte Ltd v Khek Tai Ting (trading as Soon Heng Digitax) [2011] SGHC 36.

5.118 The date at which sufficiency has to be judged is the date of filing, not the date of publication (Biogen Inc. v Medeva plc). It follows that a specification that is insufficient at the time of filing cannot be made sufficient by subsequent developments in the art.