Singapore Patent Revoked for Insufficiency of Disclosure
Sufficiency of disclosure is fundamental in patent law and key to the patent bargain for a time-limited monopoly in exchange for teaching the public how the invention works. Section 25(4) of the Singapore Patents Act (SPA) states that the patent specification must disclose the invention in a manner which is clear and complete for the invention to be performed by a skilled person, which is commonly known as sufficiency of the patent specification. A granted patent may be revoked on this ground under Section 80(1)(c) of the SPA.
Singapore Patent 115872, which is derived from PCT/IB2003/005281, covers an invention relating to chemical vapour deposition (CVD) synthetised single crystal diamond materials and methods producing them. SG 115872 is owned by Element Six Technologies, a member of the world's leading diamond company De Beers Group. Element Six Technologies contended that IIa Technologies, a Singapore-based maker of lab-grown synthetic diamonds, has infringed their patent and IIa Technologies in turn challenged the patent’s validity.
In a February 2023 judgement, the Singapore Court of Appeal (CA) held that all the claims of SG 115872 are invalid and revokes the patent in its entirety on the ground of insufficiency. The CA explained three ways in which the sufficiency of a Singapore patent could be challenged.
According to the CA, “classical insufficiency” happens if the patent specification is not clear and complete enough to enable the skilled person to perform the invention across the whole breadth of the claims without undue burden.
SG 115872 has an independent product claim for a CVD diamond material having various characteristics, as well as a method claim for a growth process for producing the diamond material according to any of the product claims. The specification must teach the skilled person to perform the growth process across the whole breadth of the method claim to produce every diamond material falling within the whole breadth of any product claim.
The claimed characteristics of the diamond material in the product claims include parameters that are defined using ranges of values, such as a birefringence parameter – phase shift δ – which does not exceed π/2. The CA construed the product claims to cover a class of CVD diamond materials, each with different characteristics, as opposed to a single diamond material.
The method claim requires the growth process to use a specific range of nitrogen gas (300 ppb to 5 ppm) as one of the growth conditions. The specification teaches that the growth process is a sensitive function of multiple growth conditions including nitrogen. However, the specification only provides limited examples of the nitrogen growth conditions, and does not offer much guidance on the other growth conditions. Relationships between the growth conditions are not elaborated upon and the specification does not teach how to consider these relationships when determining the other growth conditions. The examples only provide a few combinations of the growth conditions that include nitrogen, but there are numerous other combinations across the entire nitrogen range defined in the method claim.
As a result, the CA found that the skilled person would be unduly burdened with the need to perform extensive experiments with numerous combinations of the growth conditions to understand the relationships and work across the entire nitrogen range to produce diamond materials within the whole breadth of any product claim. Thus, the CA held that the specification does not enable the skilled person to know all the growth conditions needed to produce every diamond material falling within the class of diamond materials claimed in all the product claims, and as a result, the patent is “classically insufficient”.
According to the CA, “Biogen insufficiency” is a concept in English law which has not been recognised locally. In the United Kingdom, a specification that is not classically insufficient may still suffer from another type of insufficiency known as Biogen insufficiency, which can arise if the claim scope exceeds the technical contribution to the state of the art made by the invention. Although the CA stated that Singapore patent law has not recognised the concept of Biogen insufficiency, it made an interesting example of how this type of insufficiency can happen.
The CA cited a hypothetical claim reciting “A heavier-than-air flying machine” and the patent specification teaches only an airplane. The airplane is capable of flight and is heavier than air. As such, the specification has enabled performance of every element of the claim and can avoid a classical insufficiency attack. However, the claim scope is capable of extending to other types of flying machines that are not airplanes. The breadth of the claim exceeds what the invention has contributed to the state of the art, which is just airplanes, thus resulting in Biogen insufficiency.
According to the CA, “uncertainty insufficiency” happens if the skilled person, after following the teachings in the specification, does not know how to determine whether the product obtained or process worked falls within the claim scope.
As mentioned above, one of the characteristics of the diamond material in the product claim is the phase shift δ – which does not exceed π/2. The specification teaches that the sine function of the phase shift, |sin δ|, can be measured using known microscopy techniques. However, each |sin δ| value corresponds to many δ values, and the skilled person would not be able to determine the δ value from the |sin δ| value. The CA also found that the common general knowledge of the skilled person also does not provide workable solutions to determine the δ value.
As a result, the CA found that the skilled person would be uncertain whether the diamond material, obtained through the teachings of the specification, has a δ value which does not exceed π/2 such that the diamond material reads onto the product claim. Thus, the CA held that the skilled person, when trying to perform the claimed invention, would not be able to determine whether the obtained diamond material is inside or outside the scope of the product claim, and concluded that all the product claims are also insufficient by uncertainty.
It is interesting to note that the CA had referred to UK jurisprudence to arriving at its judgment, but it seems that the CA had applied the legal principles rather differently.
The three types of insufficiency are explained in detail in the UK IPO’s Manual of Patent Practice. Section 14.67 states that “classical insufficiency” is “the name now commonly given to what was previously understood simply as “insufficiency”, and “relates to the situation where there is no enabling disclosure.” Citing UK case law, “a patent can also be found insufficient if the steps can be characterised as prolonged research, enquiry or experiment.” In other words, a patent suffers from classical insufficiency if it imposes undue burden on the skilled person to work the invention. Section 14.79 further states that “In contrast to the situation where a patent or application is classically insufficient, there may be an enabling disclosure for some portion of the invention, but not for the full breadth of the claims. It therefore follows that restricting the scope of the claims to that which is enabled can overcome the objection… Insufficiency arising from a disclosure which does not enable the invention to be performed across the entire claim width is thus sometimes referred to as “Biogen insufficiency”.”
Thus, it follows that “classical insufficiency” under the UK practice simply means that the invention is not enabled at all by the specification and does not appear to mean that the invention needs to be enabled across the whole breadth of the claims. Instead, the term “Biogen insufficiency” under UK practice is intended to mean that the specification does not enable the invention to be performed across the entire breadth of the claim.
The Examination Guidelines by the IP Office of Singapore (IPOS) appear to follow the UK practice and specifically, paragraph 5.27 states that “The specification must provide sufficient disclosure across the full scope of the claims.” Paragraph 5.25 states that “It is not common for an objection to be raised under Section 25(4) pre-grant. The Examiner should give careful consideration when making a sufficiency of disclosure objection, and should reserve such objections for those instances where the invention cannot be readily enabled by narrowing the scope of the monopoly claimed.” Paragraph 5.86 adds that “if there is insufficient enablement across the full scope then an objection of lack of support may arise”, and Paragraph 5.99 adds that “if there is no basis for a narrower claim then an objection under Section 25(4) may be more appropriate.” It is clear that IPOS recognised that insufficient or non-enabling disclosure and excessive claim breadth are different types of insufficiency under Section 25(4). It is also clear that the Guidelines provide that Examiners should raise an objection of insufficient disclosure (i.e. classical insufficiency) under Section 25(4), whereas an objection of excessive claim breadth should be raised under Section 25(5)(c) for lack of support, since the specification would be enabled at least for that portion of the invention and the claim scope could be narrowed accordingly to overcome the objection.
Referring back to the hypothetical example of the flying machine, the CA noted that the breadth of the claim exceeds what is contributed to the state of the art as the claim extends to all other forms of flying machines that are not airplanes, thus giving rise to Biogen insufficiency. However, it is puzzling that the CA said Singapore patent law has not recognised the concept of Biogen insufficiency, because IPOS appears to recognise this type of insufficiency and the Guidelines provide that an objection of excessive claim breadth should be raised.
With the above in mind, despite relying extensively on UK jurisprudence, the CA seems to have misunderstood the UK legal principles. It is noted that the CA did not refer to the IPOS Examination Guidelines on the different types of insufficiency. Instead, the CA defined the term “classical insufficiency” as where the specification is not clear and complete enough to enable the skilled person to perform the invention across the whole breadth of the claims without an undue burden. This definition merges the insufficient disclosure and excessive claim breadth types of insufficiency, which would contradict established practice where classical insufficiency is simply that the invention is not enabled at all.
Be that as it may, while the CA may have mixed up the terms “classical insufficiency” and “Biogen insufficiency” as used under UK practice, this should have little or no impact on Singapore practice since the requirements of Section 25(4) (and Section 80(1)(c)) of the SPA are clear – the patent specification must enable the invention to be performed by the skilled person across the full breadth of the claims without undue burden. Although Biogen insufficiency issues (i.e. excessive claim scope) are more prevalent for chemical, biological, and pharmaceutical inventions, they could still affect other technical fields especially where numerical variables are defined in the claims, as illustrated in this case. Indeed, if the CA had construed the product claims to cover a single diamond material, instead of a class of diamond materials, the end result could be different.
This case highlights important considerations for patent sufficiency in Singapore and patentees should ensure the patent specification is enabling across the full breadth of the claims to fulfil their end of the patent bargain. A good practice is that claim limitations should be definitively determinable or measurable so that the skilled person knows clearly and with certainty whether a product or process falls within the scope of the claims. While the specification does not need to disclose all the details required to work the invention if they are known or part of the common knowledge of the skilled person, the level of detail should enable the skilled person to work the invention across the full scope of the claims without undue burden. Care should also be taken to avoid the use of overly broad terminology in the claims which would artificially expand the claim scope beyond the technical contribution made by the invention.