On February 7, 2020, the Singapore High Court reported its decision in the case of Element Six Technologies Ltd v. IIa Technologies Pte Ltd. [2020] SGHC 26, which treated various issues pertaining to novelty, priority date and anticipation. In particular, there are several interesting points in the decision concerning the law of anticipation which will be the focus of this article. Specifically, this article will touch on the issues related to patent entitlement to priority, novelty, parametritis claims, anticipation by an inevitable result and anticipation of ranges.

The plaintiff, a company incorporated in the United Kingdom, is part of the Element Six Group, which designs, develops and produces synthetic diamonds, and particularly specializes in the production of synthetic diamond material using chemical vapour deposition (CVD) techniques for industrial application. It is part of the well-known De Beers Group. The defendant is a company incorporated in Singapore and a major manufacturer of CVD diamonds and has its diamond growing facility in Singapore.

The plaintiff contended that the defendant has infringed two of its Singapore patents: SG 115872 (SG872) and SG 110508 (SG508). For the sake of brevity, the focus of this article will be on SG872 as most of the interesting points are related to this patent only. SG872 relates to a single crystal CVD diamond with specific characteristics, one of which is its low optical birefringence. Birefringence, simply put, is an optical property, where a ray of light, when incident upon a birefringent medium, is split into two rays. Birefringence is used to determine a diamond’s suitability for high-end optical applications.

SG872 includes one key product claim separated by eight sub-claims 1(i) to 1(viii) and one key process claim. The plaintiff asserted two sub-claims amongst the key product claim, i.e., 1(ii) and 1(iii), and the key process claim against the defendant. (Paras 15 and 16) In return, the defendant challenged the validity of the asserted claims.

Patent entitlement to priority

Priority entitlement refers to the principle that a patent application may claim priority from earlier priority applications. In fact, the different claims of a patent application, or even parts thereof, may claim priority from different priority applications and, thus, different claims of the same patent may have different priority dates.

In the instant case, the plaintiff maintained that the whole of Claim 1 has the same priority date from 2002, based on the filing date of a priority document, GB261. In contrast, the defendant asserted that while Sub-claim 1(ii) can claim the 2002 priority date from GB261, Sub-claim 1(iii) of SG872 could not claim such priority from GB261, as Sub-claim 1(iii) extended beyond what was disclosed in GB261. (Para 19) 

In determining the issues of whether Claim 1(iii) could claim priority from GB261, the High Court applied the “structured approach” set out by the English Court of Appeal in Unwired Planet International Ltd v. Huawei Technologies Co Ltd and others [2017] Bus LR 1971 (Unwired), which provided as follows: (Para 21)

1. First, to read and understand, through the eyes of the Person Skilled in the Art (PSA), the disclosure of the priority document as a whole;
2. Second, to determine the subject matter of the relevant claim.
3. Third, to decide whether, as a matter of substance and not form, the subject matter of the claim can be derived directly and unambiguously from the disclosure of the priority document.

Thean J, who delivered the decision, summarized two further points from Unwired, which can be concisely stated as follows:

Firstly, the exercise of determining priority involves asking whether the invention is directly and unambiguously derivable from the priority document, and not whether every possible embodiment of the invention is so derivable. Secondly, the priority documents must be read with the benefit of the common general knowledge, which forms the factual matrix against which the disclosure in the priority document is assessed by the PSA.


Applying these principles in this context, the High Court agreed with the plaintiff that whether or not Claim 1(iii) is broader than Claim 1(ii) is not relevant to the issue; and that the defendant does not contend that there is any difference in the inventive concept of both sub-claims. Both Claims 1(ii) and 1(iii) are simply different ways of quantifying the birefringence of the CVD, with different parameters. (Para 24) The invention in question, i.e. a CVD diamond of low birefringence, is directly and unambiguously derivable from the priority document GB261, and thus, Claim 1(iii) was entitled to claim priority from GB261.

Novelty: Parametritis

Another ancillary point that was raised by the defendant was that the claim defined in terms of birefringence suffers from parametritis. A parametric claim is one where the claim is defined by technically meaningless and arbitrary parameters. (Para 55). This is the practice of seeking to re-patent prior art by limiting claims by reference to a series of parameters which were not mentioned in the prior art. Sometimes it includes reference to parameters measured on test equipment which did not exist at the time of the prior art.

Notwithstanding the court’s holding that parametritis does not anyway constitute an independent ground for patent invalidation, the High Court still proceeded to reject the defendant’s argument on the facts of the present case. Although, in prior art, there was a technique of cross-polar imaging which allowed one to assess birefringence, it only provided a qualitative assessment. However, Claims 1(ii) and (iii) of the plaintiffs’ patent provide for an invention that offers a quantitative assessment. Therefore, the High Court held that the birefringence parameter is not technically meaningless. (Paras 59-60)

Novelty: Distinctiveness

Regarding the issue of novelty, although the High Court applied the general and well-established case laws, there were also a few ancillary issues of interest.

One of the issues pertaining to novelty that the court explored was the law relating to product-by-process patents. In the instant case, the issue was whether the CVD diamond produced by the plaintiffs’ process is a distinct type of diamond. (Para 39) The High Court cited Terrell on the Law of Patents (Terrell) and stated that “[t]he essential issue is whether the product, when produced by the process is itself a new, or unique, product.” (Paras 45-46)

In the instant case, based on the adduced evidence, the High Court held that CVD diamond is a distinct type of diamond as the distribution, nature and combination of defects differ among the three types of diamonds [CVD mined and HPHT]. (Para 54)

The defendant had argued that the defects in CVD diamonds can also be found in natural and HPHT diamonds and that the plaintiffs’ expert could not point defects which existed uniquely in CVD diamonds. However, the court had dismissed this argument and upheld the distinctiveness of the CVD diamond. Even if the defects associated with a CVD diamond are only typical and therefore may be found in diamonds of other types as well, it appears that these typical differences between the various types of diamonds had been found by the court to substantiate the distinctiveness of the CVD diamond.

Novelty: Use of publications post-dating the date of priority

An ancillary issue in novelty in this case relates to the use of publications post-dating the priority date for novelty (Para 35). The High Court followed the English case of Smith & Nephew Plc and Convatec Technologies Inc [2013] RPC 6 and held that “one ought to distinguish between the use of such publications to subjectively interpret the prior art and as a means to objectively establish a scientific fact.” The former is not permissible given the rule ex-post-facto analysis but there is nothing objectionable with using publications post-dating the date of priority as a way of proving a scientific fact.

Novelty: Correlations between physical properties – anticipation by inevitable result

For novelty arguments against the product claims, the defendant had raised multiple prior art documents. While none of the prior arts explicitly disclosed the birefringence parameters as well as the specific claimed values, the defendant attempted to rely on three types of evidences to show that the claimed invention in the plaintiff’s patent had been inevitably anticipated by prior art:

1. Prior art that enables a PSA to make CVD diamond with certain physical properties, which were alleged to be correlated with optical birefringence;
2. Prior art that enables a PSA to make CVD diamond material suitable for specific applications with a birefringence valuje within the SG872 range; and
3. Prior art, where the Defendant seeks to show that the Claim 1 product inevitably results from a similar method of teaching. (Para 41)

The High Court analyzed (a) - (c) with respect to two prior art: WO ‘633 and WO ‘634. For the sake of brevity, we will limit our discussion to (a).

The High Court decided point (a) by identifying the relevant parameters such as dislocation density, charge collection efficiency, etc in the prior arts adduced by the defendant. The rationale behind the defendant’s reliance on these prior arts can be illustrated with an example. If the prior art could enable a PSA to make a CVD diamond of a certain dislocation density, and it is established that this specific dislocation density results in a birefringence value of the plaintiff’s patented product, the prior art will then anticipate the patent claim.

Ultimately, the High Court held that while one does not need to prove a precise mathematical correlation between the identified parameter and birefringence, it will suffice if the identified parameter will have a birefringence of the specific value as claimed in the product claim. However, on the facts, the defendant's evidence failed to meet the burden imposed by the High Court that the identified parameter will have a birefringence of less than 10-4. (Paras 65-91)

Novelty: Anticipation of ranges

For the novelty arguments against the process claim, Claim 62, the defendant had also raised multiple prior arts. Claim 62 taught the deliberate and controlled addition of nitrogen in a specified range in the production process of the plaintiff. In this regard, the defendant advanced the argument that the process claim would be anticipated if the prior art disclosed a single value that fell within the range of values defined in Claim 62. Where there was an overlap between the ranges of the prior art and Claim 62, the Defendant argued that there is anticipation if a PSA would have seriously contemplated applying the prior art in the region of overlap.

The High Court elaborated in considerable detail the law on anticipation of ranges using the case of Jushi Group Co Ltd v. OCV Intellectual Capital LLC [2019] RPC 1 (Jushi). The court ultimately stated: “[w]hen dealing with overlapping ranges, the question to be asked is whether the prior art taught the (PSA) that they should operate in the area of the combined overlap of the ranges.” (Paras 226-234, Particularly Para 234)

Of the prior arts advanced by the defendant, we will limit ourselves to one, SG508, a patent relating to the changing of colour of a CVD diamond. The High Court found that the examples given in the priority document of SG508 teach a specific value of 10ppm (parts per million) while the patent itself gave multiple ranges with the widest one being from 0.5 to 500 ppm but stated that the most preferable range was between 2 and 30 ppm. Claim 62 of the plaintiff’s patent specified a range from 0.3 ppm to 5 ppm.

Since Claim 62’s range was encompassed by the widest range in the prior art, the combined overlap of the ranges between the prior art and the plaintiff’s patent was between 0.5 and 5 ppm.

The High Court found that the most preferred range in the prior art (2 to 30 ppm) as well as the specific value used in the examples given in the prior document (10 ppm) would have pushed the PSA away from operating in the combined region of overlap (0.3 to 5 ppm).

Conclusion

In conclusion, this case offers a comprehensive look at issues in patent law, spanning from the fundamentals of priority entitlement, novelty related to product-by-process claims, parametritis, anticipation by inevitable result and anticipation of ranges. The high thresholds set by the court for the defendant to satisfy that the claimed invention of the plaintiff has been anticipated signals the court’s taking the rights of patent proprietors seriously.