The Singapore High Court decision of Element Six Technologies v Ila Technologies Pte Ltd  SGHC 26 considered the issue of patent entitlement. Entitlement to priority is an issue throughout the lifecycle of a patent. For example, it is relevant as Singapore patent examiners do consider entitlement to priority during the local examination stage. The examination guidelines on priority were revised in March 2020 to include the application of Element Six Technologies v Ila Technologies Pte Ltd  during examination. An understanding of the principles is also important across the life-cycle of a patent.
It is historical and well established that a patent application may claim priority from one or more earlier priority applications with different priority dates. The claims in a patent application may thus have different priority dates.
“The combination of features, as defined in a particular claim, is the filing date of the earliest application whose disclosure supports that feature or combination” [Examination Guidelines for Patent Applications at IPOS, 26 March 2020, section 3.88].
In Element Six Technologies v Ila Technologies Pte Ltd , the “structured approach” was taken to consider entitlement to priority:
(a) First, to read and understand, through the eyes of the PSA, the disclosure of the priority document as a whole.
(b) Second, to determine the subject matter of the relevant claim.
(c) 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.
In particular, Thean J summarised that:
…..……The exercise of determining priority involves asking whether the invention is directly and unambigously derivable from the priority document from the priority document, not whether every possible embodiment of the invention is so derivable.
The priority document must be read with the benefit of the common general knowledge which forms the factual matrix against which the technical disclosure is assessed. Consequently, the disclosure may mean something different to a PSA who possesses the requisite knowledge than it does to someone reading the document without that knowledge. That observation is particular relevant in a case where one is concerned not merely with what is made explicit by the document, but also with what is implicit in it, given that both explicit and implicit disclosure may be taken into account for priority.
The structured approach in a nutshell:
The earlier priority document may disclose the subject matter explicitly or implicitly.
It is not necessary for every possible embodiment of the invention to be described in the priority document.
The common general knowledge of the PSA should be taken into account in considering whether the invention is directly and unambiguously derivable from the priority document.
In Element Six Technologies v Ila Technologies Pte Ltd , the priority entitlements of parts (ii) and (iii) of claim 1 of SG 115872 (“SG 872”) were at issue.
The subject matter of claim 1(ii) relates to a CVD diamond of low optical birefringence, defined with the parameter of |sin δ| does not exceed 0.9.
The subject matter of claim 1(iii) relates to a CVD diamond of low birefringence, defined with a different parameter that the maximum value of Δn[average] does not exceed 1.5 x 10-4.
The defendant (Ila Technologies Pte Ltd) accepted that the priority date of claim 1(ii) is the 20 November 2003 filing date of the priority application GB 0227261.5 (“GB 261”) but contended that the claim 1(iii) was not supported by the disclosure of GB 261.
Thean J in her decision noted that the defendant does not contend that there is any difference in the inventive concept in the method between GB 261 and SG 872. The defendant does not suggest that there is any difference in the process taught in GB 261 and SG 872, which is capable of giving rise to the claimed product in claim 1.
Thean J then concluded that “Claims 1(ii) and 1(iii) are simply different ways of quantifying or measuring of measuring the optical birefringence of the CVD diamond produced through the process disclosed in GB 261 and SG 872, through the respective parameters” and “A low birefringent CVD diamond within the range claimed in claim 1(iii) can be derived directly and unambiguously from the priority document GB 261. There is implicit disclosure, and no difference in substance.”
As such, claim 1(iii) is entitled to claim priority from GB 261 and has the earlier priority date of 21 November 2002. Consequently, certain prior art was therefore not citable against claim 1 of SG872.
s 14(3) prior art
Later in Element Six Technologies v Ila Technologies Pte Ltd , Thean J decisively determined that for two prior art document (SG 506 and SG508) published after the priority date of SG 872, the respective subject matter from the two prior art document were not entitled to the respective claimed priority date but only entitled to the respective filing date (which was after the priority date of SG 872) and thus could not be cited for novelty against SG 872.
Although Thean J did not mention the structured approach, she may have applied the structured approach in making this determination.
Nevertheless, she went on further and concluded that even on the assumption that even if the claimed priority date of SG 506 was valid and predates the priority date of claim 1, SG 506 does not anticipate this claim.
In a written opinion issued for a Singapore patent application, the Singapore patent examiner considered that claims MM to NN were not entitled to the earlier priority dates. Reference was made to Element Six Technologies v Ila Technologies Pte Ltd and the revised examination guidelines in the written opinion.
According to the examiner, a first set of claims specify a dosage range of between 0.1 and 1.2 mg/kg which is not disclosed in the two priority documents. In the actual claim set, the independent claim defines a range between 0.1 and 1.2 mg/kg, while the dependent claims define various narrower ranges.
The examiner recognized that the two priority documents suggested a dose of between 0.4 and 1.0 mg/kg.
In the written opinion, the examiner established that the dosage range of 0.1 and 1.2 mg/ml in claims MM-NN were entitled to the filing date of the application.
On review of the priority documents, we note that the document also disclosed various other ranges; such as between 0.05 and 2.0 mg/kg, between 0.2 and 1.5 mg/kg, between 0.4 and 0.8 mg/kg, between 0.5 and 0.6 mg/kg for example.
The examiner’s opinion appears to be that using the structured approach, no other dosage ranges can be derived from the priority documents.
Considering the examiner’s opinion, it may be worth considering including at least one further claim specifying a dose of between 0.4 and 1.0 mg/kg and other dependent claims specifying dosage ranges from the priority document.
Separately, the examiner considered that a second claim set (claims XX to YY) defining the dosage regime between 30 and 80 mg per day in this application were not entitled to the earliest priority date of the first priority document. Claims XX to YY were considered entitled to the priority of the filing date of the second priority document.
On a review of the second priority document, it is noted that the relevant section in the second priority document the examiner referred to mentions 15 mg and 40 mg BID (twice a day) which would equate to a total of 30 mg and 80 mg per day. With these two dosages, the examiner derived and accepted that the second priority document provides entitlement to priority for the range of between 30 and 80 mg per day in claims XX to YY; differing somewhat to his opinion with respect to the ranges recited in the first claim set.
Prior art cited
There were two prior art documents cited in the search report and written opinion. One document published before the priority art was used for the novelty and/or inventive objections. The other P, X document was not cited for novelty objections.
It may be worthwhile to consider including a short argument when responding to the objections that the applicant does not agree with the examiner’s opinion on lack of priority entitlement without detailed reasonings.
For other cases, it may be necessary to address objections in view of intermediate prior art documents in order to obtain allowance of the SG patent application, either by persuading the examiner to accept priority entitlement or narrow the claims.
Points to note
- The outcome of the local examination compared to Element Six Technologies v Ila Technologies Pte Ltd  is summarised below.
(a) In Element Six Technologies v Ila Technologies Pte Ltd  before the Singapore High Court, claim 1(iii) of SG ‘872 was found to be entitled to the earlier priority date of GB ‘261.
(b) During local examination of a Singapore patent application in which the examiner made reference to Element Six Technologies v Ila Technologies Pte Ltd , one set of claims was considered to be entitled only to the filing date of the application while a second set of claims was not entitled to the earliest priority date of the earliest priority document but entitled to the priority date of the other priority document.
- Following on from the decision of Element Six Technologies v Ila Technologies Pte Ltd  and the revised examination guidelines, Singapore patent examiners may consider the issue of entitlement to priority more closely during local examination.
- Patent applicants may need to carefully consider the disclosure of the priority applications at the point of filing. At the point of filing the patent application claiming priority, applicants can also make use of the structured approach adopted in Element Six Technologies v Ila Technologies Pte Ltd  as a guide to determine the subject matter that may be directly and unambiguously derived from the priority application. In any case, performing this structured approach analysis is a useful exercise that will be pertinent throughout the life cycle for applicants intending to pursue patent protection in Singapore.
- It may be necessary to address objections in view of intermediate prior art documents in order to obtain allowance of the SG patent application, either by persuading the examiner to accept priority entitlement or narrow the claims.
If no novelty and/or inventiveness objections are raised with respect to intermediate prior art documents, it may be worthwhile to consider including a short argument when responding to the objections that the applicant does not agree with the examiner’s opinion on lack of priority entitlement without detailed reasonings.