Anonymised Summary of Patent Judgment

Factual and Procedural Background

Judge [Last Name] delivered a judgment following a trial of a patent action concerning the design of the outer sheath of optical fibre cables (OFCs) used for air-blown installation. The Claimants (Company A and Company B) are the proprietor and exclusive licensee respectively of EP 3796060 B1 (priority date 11 October 2018). The Defendant (Company C) was accused of infringing the Patent by selling a range of OFCs referred to as the "Celesta" products; the Defendant denied infringement and counterclaimed for invalidity on multiple grounds.

The trial was conducted with legal teams appearing for both sides: the Claimants were represented by Attorney [Pritchard] and Attorney [Darby], instructed by Law Firm A; the Defendant was represented by Attorney [Nicholson] and Attorney [Gamsa], instructed by Law Firm B. Each side called two expert witnesses: a Cable Expert (design/manufacture/installation) and a Measurement Expert (3D optical surface profiler operation). Fact witnesses were relied upon by both parties but only some gave evidence: Fact Witness (Company A) gave evidence about the repeat experiment and associated image production; Fact Witness (Company C) introduced a post-priority Gas Leakage Study and Company C provided a Product and Process Description (PPD) explaining the Celesta products (signed by a Company C IP representative) which was not challenged.

The court received an agreed technical primer / statement of common general knowledge (CGK) covering OFC technology, ducting (main, sub-duct, micro-duct), air-blown installation machinery and testing (including IEC Method E24), cable structures (multi-loose tube and central core), and outer-sheath surface designs. The trial addressed claim construction, validity (including inventive step / obviousness, insufficiency and uncertainty), and infringement based on experiments performed by the Claimants on a sample of the Defendant's Celesta 432F cable (the "Sample Cable"). The Claimants sought to amend claim 1 to align with the form upheld by the European Opposition Division and relied on results from repeat experiments to prove infringement of the Sample Cable and to extrapolate to other Celesta products.

Legal Issues Presented

1. What is the correct construction of claim 1 of the Patent (in particular: the meaning of "micro-duct" and the manner of calculating the cross-sectional area A of the recesses using the closed curve L described as circular or elliptical)?
2. What is the technical contribution of the Patent and whether the claims are valid (issues including insufficiency, uncertainty and inventive step / obviousness over cited prior art such as Pedder and the AFL brochure)?
3. Whether the Claimants' repeat experiments reliably establish that the Defendant's Celesta 432F Sample Cable falls within the claimed cross-sectional area range and thus infringes, and whether that finding can be extrapolated to other Celesta products.
4. Whether combinations of prior art (including collocation arguments) render the Patent obvious.

Arguments of the Parties

Claimants' Arguments

• The Patent identifies a technical contribution: the seal tightness at the air inlet (pump) affects air-blown performance and an optimised recess cross-sectional area (A) in the sheath (1.3 mm2 to 4.8 mm2) improves blowability in micro-ducts.
• Micro-ducts as a matter of CGK include ducts with inner diameter up to 16 mm; the amended claim's limitation to cables "suitable for insertion into a micro-duct" cures breadth/insufficiency concerns.
• The claim should be construed purposively and practically; the closed curve L is an approximation of the lip of the pump seal and need not be a perfect geometric circle/ellipse for real-world cables.
• The repeat experiments (witnessed) reliably show that the Sample Cable falls within the claimed area range; measurement criticisms do not undermine the result and the extrapolation to other Celesta products is supported by die/draw-down information in the PPD and expert evidence.

Defendant's Arguments

• The claim is insufficient/uncertain and/or lacks inventive step. In particular, the Defendant argued that: (a) the claimed range for A is given in absolute terms without adequate scaling or disclosure for different cable sizes; (b) other features in the specification (e.g. rib twist, stiffness) are necessary for the promised effect and their omission from the claim renders it broader than the technical contribution; and (c) the claim is unclear on how to calculate the comparator closed curve L for non-circular real-world cables.
• Micro-duct should be limited as matter of CGK to smaller diameters (internal 13 mm / outer 16 mm typical) which, when combined with a fill-factor CGK limit (≤70%), would materially restrict the claim's scope and exclude the Defendant's 432F cable.
• Prior art (notably Pedder and a commercial AFL brochure) either anticipates or renders the claim obvious. The Defendant argued a collocation approach (combine teaching of IBR disclosure with ribbed jackets) and relied on expert modelling to show that variants derived from the prior art would fall within the claimed range.
• The Claimants' experiments were methodologically flawed (choice of single cross-section, sample preparation, measurement technique, and an unexplained discrepancy between measured diameter and PPD nominal diameter) and therefore do not establish infringement; the Claimants should not be permitted to extrapolate from the Sample Cable to other products without further proof.

Table of Precedents Cited

Court's Reasoning and Analysis

The court's analysis proceeded through the following main steps, based only on material in the opinion:

1. Composition and character of the skilled team and CGK. The court accepted the parties' agreement that the notional skilled team would have around three years' experience in OFC design, manufacture and installation; the field is practical and empirical, and the Measurement Experts were called only to test the experiments. The agreed CGK covered duct sizes, cable structures, extrusion/sheathing processes, cable blowing machines and relevant standards (IEC).
2. Micro-duct construction as a CGK matter. The court considered conflicting evidence on the meaning of "micro-duct." After reviewing standards, FTTH handbooks and commercial brochures, the court found that micro-ducts as a matter of CGK were not limited in the overly narrow way the Defendant contended and included inner diameters of 16 mm. The court concluded the skilled person at the priority date would be able to identify a micro-duct.
3. Identification of the Patent's technical contribution. The court analysed the specification and concluded the technical contribution comprised (a) identifying that the tightness of the seal at the air inlet (pump) affects air-blown performance, and (b) disclosing a range of recess cross-sectional areas (A) (1.3 mm2 to 4.8 mm2) which are said to optimise the seal to improve blowability. The court treated this contribution as including identification of the problem as well as the alleged solution.
4. Construction of claim 1 (closed curve L and calculation of A). The court adopted a purposive and practical construction. It held that the closed curve L described as circular or elliptical should be understood as an approximation of the lip of the pump seal in real-world cables and need not be a mathematically perfect circle or ellipse. The curve should, so far as practicable, touch the protrusions; it may not be purely tangential, it need not have an exactly coincident central axis to the cable, and averaging or approximation is acceptable in non-circular cases. The court found the claim capable of being implemented and not conceptually uncertain in the sense required to invalidate it for insufficiency.
5. Assessment of breadth / sufficiency attacks. The Defendant's multiple insufficiency arguments were analysed in three groupings (reliance on other specification features like rib twist; absence of diameter limitation; squeeze on protrusion design). The court rejected the rib-twist argument (the specification presents features independently and absence of rib twist did not render the invention inoperable), rejected the argument that diameter renders the claim insufficient (micro-duct size and pump constraints limit realistic cable sizes), and rejected the squeeze argument because the claim targets cross-sectional area which the skilled person could aim for and there was no evidence of realistic designs within the claims that would not work.
6. Obviousness over prior art (Pedder and AFL brochure) and collocation. The court examined Pedder (US 7,087,841 B2) and the AFL brochure. It found that Pedder disclosed ribbed/protrusion designs and suggested aerodynamic lift effects but did not address sealability at the air inlet in the manner of the Patent; Pedder did not provide a reliable route to the claimed invention, particularly for intermittently-bonded ribbons (IBRs) about which the skilled person had limited experience. The AFL brochure disclosed ribbed jackets for conventional cables but not IBRs with ribs (IBRs were shown with a smooth exterior), suggesting the skilled person would not have expected ribbed jackets to work on IBRs. The court found that the Defendant's experts' written evidence injected hindsight (an appreciation of seal leakage not in the CGK). The collocation argument (combining separate prior art teachings) failed because the features interact for blowability and were not truly independent; therefore collocation did not make the claim obvious.
7. Evaluation of the Claimants' experiments and measurement methods. The court scrutinised the Claimants' repeat experiments on the celesta 432F Sample Cable and criticisms raised by the Defendant: sample representativeness, sample preparation, an unexplained measured diameter discrepancy (13.52 mm measured versus a PPD nominal 12.7 mm ± 0.3 mm), and sensitivity of area to protrusion height. The court found that (a) the Defendant had the material means to test or rebut but did not do so; (b) the Measurement Experts were fair and impartial and the repeat experiments were witnessed; (c) while the Claimants' measurement methodology (a quadrant method and fitting of arcs) was over-engineered and imperfect, the Defendant failed to demonstrate that reasonable alternative methodologies would have produced materially different results; and (d) the court therefore accepted the repeats as establishing that the Sample Cable had a recess area within the claimed range.
8. Extrapolation to other Celesta products. The court addressed whether the infringement finding for the Sample Cable could be extended to other Celesta products. The Claimants had narrowed their pleaded reliance and did not seek to rely on the experiments alone to prove that every sample of 432F or other products infringe. The court accepted an extrapolation exercise by the Claimants' cable expert (using die diameters and draw-down ratios) and found that, on the evidence (and subject to the Claimants' withdrawal of claims on 576F cables), the other Celesta products with fibre counts 144, 288 and 432 also infringed.

Holding and Implications

Holding: The court held that the Patent is valid and that the Defendant's Celesta 432F Sample Cable infringed claim 1 as amended; the court also found infringement by the Defendant's other Celesta products with fibre counts 144, 288 and 432 (the Claimants abandoned their claim on 576F products).

Implications: The direct consequences are (a) the Patent survives the Defendant's attacks for insufficiency, uncertainty and lack of inventive step on the grounds argued at trial; (b) the repeat experiments were accepted as establishing infringement of the Sample Cable and the Claimants' extrapolation to other listed Celesta products was accepted on the pleaded evidence; and (c) the court rejected the Defendant's obviousness, collocation and measurement challenges on the facts of this case. The opinion does not lay down a new general legal precedent beyond application of existing authorities to these facts.