Patents - Promptu Systems Corporation v Sky UK Ltd.


Patents Court (Mr Justice Meade) Promptu Systems Corporation v Sky UK Ltd and others [2021] EWHC 2021 (Pat) (19 July 2021)

This was a claim for patent infringement by Promptu Systems Corporation ("Promptu") against Sky UK Ltd. and various related companies ("Sky") and a counterclaim by Sky for revocation. The patent in suit had been granted for a system and method of voice recognition near a wireline node of a network supporting cable television and/or video delivery by the European Patent Office under publication number EP1290889B1. The action and counterclaim came on before Mr Justice Meade on 14 to 16 June 2021 and his lordship delivered judgment on 19 July 2021 (see Promptu Systems Corporation v Sky UK Ltd and others [2021] EWHC 2021 (Pat) (19 July 2021). By para [241] of his judgment, Mr Justice Meade held that the patent was invalid and should be revoked but had it been valid it would have been infringed.

The Invention
The abstract describes the invention as follows:

"A method and system of speech recognition presented by a backchannel from multiple user sites within a network supporting cable television and/or video delivery is disclosed."

The judge discussed it between para [107] and para [114] by reference to the following drawing:

The key aspects of Fig 3 are that each user has a remote control and a set-top box. The users' set-top boxes communicate with a central server known as a “wireline node”.  Individual users are able to give speech commands using microphones in their remote controls.   Each of those microphones has a “push-to-talk” ("PTT")  button which begins the process of speech recognition by informing the system that the subscriber is about to speak and also to provide immediate address information. Address information identifies the user site at which the speaking occurs.  Immediately on pressing the push-to-talk button, an icon appears on the user’s screen to show that their input has been received and is being processed.  At the wireline node, speech processing is done centrally for all the users. This can include fetching and using speech parameters specific to individual users. The users’ speech commands are responded to by the wireline node sending back customized entertainment and/or information. One source of information used is a “content engine” in the network, which is essentially a database of what is available.

Claim 13
The only claim in issue was claim 13.   Promptu proposed the amendment that appears below,   Both sides broke it down into integers which the judge reproduced in the following table:

Amended Claim 13

Sky No.


Promptu No.


A method of using a back channel containing a multiplicity of identified speech channels from a multiplicity of user sites (1100)



presented to a speech recognition system (3200) at a wireline node (1300) of a network


supporting at least one of cable television delivery and video delivery, comprising the steps of:


receiving said back channel to create a received back channel,



partitioning said received backchannel into a multiplicity of received identified speech channels;



processing each of said multiplicity of said received identified speech channels with said speech recognition system to create corresponding recognized speech content for each received identified speech channel;



responding to said recognized speech content to create a recognized speech content response that is unique for each of said received identified speech channels; and



individually controlling the delivery of entertainment and information services to each user site (1100) in accordance with said recognized speech



wherein said network comprises a content engine from which said speech recognition system receives content status information;



wherein each user site contains at least one set top box which is associated with a remote control containing a microphone and a talk button;



wherein the analogue sound signals picked up by the microphone are pre-processed by the remote control;



and wherein the set top box receives a radio frequency (RF) signal from the remote control;


and wherein upon depressing the talk button on the remote control data are sent to the wireline node alerting the system as to the user site and a potential input.



Sky Q System
Promptu complained that the defendants' "Sky Q" system infringed its patent. At para [156] the judge described that system as follows:

"i) The Sky Q system includes several connected systems:
a) A VREX voice platform which is hosted on Amazon Web Servers (“AWS”) in the UK.
b) An ASR function provided by Google which turns voice data into text. This may or may not take place in the UK and Sky does not know for any individual instance whether it does or does not.
c) Sky Search: a content engine containing searchable metadata for the content available to the user. This is also hosted on AWS, but in Ireland.
ii) The systems are connected via the internet.
iii) In particular, when a user presses the voice button on their remote control, a WebSocket individual to that user is opened, which involves sending, among other things, the user’s IP address to the VREX.
iv) When, as will frequently be the case, multiple users activate voice command at the same time, the VREX will receive data from all of them and separate it out into each user’s speech using their IP addresses.
v) It is the VREX that sends the response back to the user, once it has received what it needs from the ASR and content engine."

Mr Justice Meade noted at para [129] of his judgment that the issues of claim construction in this case were about the normal meaning of claim 13 as proposed to be amended and not about equivalence. He found it convenient to refer to paras [18] and [19] pf Lord Justice Floyd's judgment in Saab Seaeye Limited v Atlas Elektronik [2017] EWCA Civ 2175 for the applicable principles:

“[18] There was no dispute about the principles which apply to the construction of patent claims. Both parties relied, as did the judge, on the summary in this court's judgment in Virgin Atlantic v Premium Aircraft [2010] RPC 8 at [5]:

‘(i) The first overarching principle is that contained in Article 69 of the European Patent Convention.
(ii) Article 69 says that the extent of protection is determined by the claims. It goes on to say that the description and drawings shall be used to interpret the claims. In short the claims are to be construed in context.
(iii) It follows that the claims are to be construed purposively - the inventor's purpose being ascertained from the description and drawings.
(iv) It further follows that the claims must not be construed as if they stood alone - the drawings and description only being used to resolve any ambiguity. Purpose is vital to the construction of claims.
(v) When ascertaining the inventor's purpose, it must be remembered that he may have several purposes depending on the level of generality of his invention. Typically, for instance, an inventor may have one, generally more than one, specific embodiment as well as a generalised concept. But there is no presumption that the patentee necessarily intended the widest possible meaning consistent with his purpose be given to the words that he used: purpose and meaning are different.
(vi) Thus purpose is not the be-all and end-all. One is still at the end of the day concerned with the meaning of the language used. Hence the other extreme of the Protocol - a mere guideline - is also ruled out by Article 69 itself. It is the terms of the claims which delineate the patentee's territory.
(vii) It follows that if the patentee has included what is obviously a deliberate limitation in his claims, it must have a meaning. One cannot disregard obviously intentional elements.
(viii) It also follows that where a patentee has used a word or phrase which, acontextually, might have a particular meaning (narrow or wide) it does not necessarily have that meaning in context.
(ix) It further follows that there is no general 'doctrine of equivalents.'
(x) On the other hand purposive construction can lead to the conclusion that a technically trivial or minor difference between an element of a claim and the corresponding element of the alleged infringement nonetheless falls within the meaning of the element when read purposively. This is not because there is a doctrine of equivalents: it is because that is the fair way to read the claim in context.
(xi) Finally purposive construction leads one to eschew the kind of meticulous verbal analysis which lawyers are too often tempted by their training to indulge.’

[19] Sub-paragraph (ix) must now be read in the light of the Supreme Court's judgment in Actavis v Lilly [2017] UKSC 48 , which explains that, at least when considering the scope of protection, there is now a second question, to be asked after the patent claim has been interpreted, which is designed to take account of equivalents. There was some reference in the written arguments to the impact of that decision on the present case. In the end, however, Mr Mellor disclaimed any reliance on any doctrine of equivalence for the purposes of supporting an expansive scope of claim in the context of invalidity. That issue will therefore have to await a case in which we are called upon to decide it.”

The judge identified the following interpretation issues at [131]:

"i) Is claim 13 as proposed to be amended limited to closed TV cable networks? “Closed TV cable networks” was the phrase used by Sky. Its definition was not entirely rigorous, partly because it spanned multiple claim features, but I understood it to include the requirements that the infrastructure be of the typical coaxial cable kind, that it be owned by the cable company, and that FDMA or TDMA be used for multiplexing. If claim 13 is so limited then there is no infringement because the relevant messages in Sky Q are sent over the public internet. This point involves consideration of a number of claim features but also has to be assessed in the context of the claim as a whole. I will call this “the network issue”.
ii) Does claim 13 cover sending data as part of making an initial connection to the wireline node, or is it limited to sending data after a connection has been set up? If the latter then there is no infringement because the data transmission relied on by Promptu is part of the WebSocket’s being set up."

His lordship considered the first issue between [132] and [152] and concluded that claim 13 as proposed to be amended is not limited to closed TV cable networks and does not exclude networks that use the internet.   As for the second issue, he said at [154] that there was no basis in the claim for the limitation which Sky sought to impose, namely that there must be a pre-existing connection over which the data has to be sent.  

Sky had accepted that if it was wrong on the two construction issues the judge had discussed above, then Sky Q fell within the scope of the claims as far as their meaning was concerned. Since his lordship had held against Sky on the two points, that conclusion had to follow.  There remained the question of territoriality.  Not all parts of the Sky Q system were in the UK.  Similar issues had arisen before in Menashe v. William Hill [2002] EWCA 1702, RIM v. Motorola [2010] EWHC 188 (Pat) and Illumina Inc v Premaitha Health Plc [2017] EWHC 2930 (Pat). In his lordship's view, the principles derivable from these cases were: 

"(a) the Court’s task is to identify by whom and where, in substance, the method is being used; and 
(b) it is relevant to take into account that for some steps it simply may not matter where processing power is located."

He reasoned as follows:

"[162] In the present case, all features of the claim except the speech recognition and content engine access take place in the UK. The method is, overall, a method of using a back channel which takes place at the wireline node, i.e. at the “server” end, remote from the user. User input triggers part of the method, i.e. sending data from the user end identifying the user, but it is not the user who puts the method into effect.
[163] The central part of the processing at the server end is the partitioning of incoming signals on the back channel and subsequent provision of the unique recognised speech content response and individual delivery of services accordingly. Content engine access and speech recognition are subordinate and in the Sky Q system are essentially sub-contracted; I consider that it is a matter of indifference where those two functions take place, an impression that is fortified by the fact that Sky do not even know where the ASR takes place for any given user interaction."

 He formed the view that the method was performed in the UK and that had the patent been valid it would have been infringed.

Sky counterclaimed for the revocation of the patent on the grounds of obviousness and added matter. His lordship considered added matter contention first.

Added Matter
One of the grounds upon which a patent may be revoked is that the matter disclosed in the specification of the patent extends beyond that disclosed in the application for the patent, as filed (s.72 (1) (d) of the Patents Act 1977).  Another is that the protection conferred by the patent has been extended by an amendment which should not have been allowed (see s.72 (1) (e)).  Mr Justice Meade summarized the issue at subparagraph (v) of para [8]:

"Added matter. There were two points. One arose from granted claim 1 and the other from the proposed amendment to claim 1. So formally the second was an objection to amendment rather than an allegation that the Patent was invalid as it stood, but since the application to amend was unconditional it would have had the effect, if made out, that the Patent would be revoked. I have therefore dealt with both points together under the heading of validity, which is also convenient because much the same considerations apply to both."

He amplified those allegations between paras [175] and [177]:

"[175]  The first was that the 'individually controlling' functionality to be found in claim feature 1H was only disclosed in the context of a closed TV cable system. In particular, Sky pointed to page 9 of the application as filed, lines 8 to 23:

'The invention comprises a multi-user control system for audio visual devices that incorporates a speech recognition system that is centrally located in or near a wireline node, and which may include a Cable Television (CATV) Headend. The speech recognition system may also be centrally located in or near a server farm a web-site hosting facility, or a network gateway.

In these embodiments of the invention, spoken commands from a cable subscriber are recognized and then acted upon to control the delivery of entertainment and information services, such as Video On Demand, Pay Per View, Channel control, on-line shopping, and the Internet. This system is unique in that the speech command which originates at the user site, often the home of the subscriber, is sent upstream via the return path (often five to 40 MHz) in the cable system to a central speech recognition and identification engine. The speech recognition and identification engine described herein is capable of processing thousands of speech commands simultaneously and offering a low latency entertainment, information, and shopping experience to the user or subscriber.'

[176]     The second allegation was that the content engine was only disclosed in the application in a particular context, being an “augmented” node or headend and that, relatedly, the augmented node (or headend) was taught as being of a kind disclosed in a co-pending application. Sky referred in particular to page 59, lines 13-20:

'As used herein, the adjective augmented is used to refer to a node incorporating at least one embodiment of the invention.

Augmented node 1310 may control and support optimized upstream communication as disclosed in the co-pending application serial number 09/679, 115, entitled "Increased Bandwidth in Aloha-based Frequency Hopping Transmission Systems" by Calderone and Foster, both inventors of this application and commonly assigned to AgileTV, and incorporated herein by reference.'

[177] The teaching of a content engine is then found in, in particular, the embodiments of figures 23 and 26, which involve augmented nodes and headends, respectively."

Before addressing these issues, the learned judge referred to paras [53] to [60] of Lord Justice Kitchin's judgment in Nokia v. IPCom [2012] EWCA Civ 567:

“[53]    Then, in decision T 0331/87, Houdaille/Removal of feature [1991] E.P.O.R. 194, the TBA laid down a three part test at [3]–[6]:

‘3. For the determination whether an amendment of a claim does or does not extend beyond the subject-matter of the application as filed, it is necessary to examine if the overall change in the content of the application originating from this amendment (whether by way of addition, alteration or excision) results in the skilled person being presented with information which is not directly and unambiguously derivable from that previously presented by the application, even when account is taken of matter which is implicit to a person skilled in the art in what has been expressly mentioned (Guidelines, Part C, Chapter VI, No. 5.4). In other words, it is to examine whether the claim as amended is supported by the description as filed.
4. In the decision T 260/85 (Coaxial connector/AMP, OJ EPO, 1989, 105) the Board of Appeal 3.5.1 came to the conclusion that “it is not permissible to delete from a claim a feature which the application as originally filed consistently presents as being an essential feature of the invention, since this would constitute a violation of Art.123 (2) EPC” (cf. Point 12 and Headnote). In that case the application as originally filed contained no express or implied disclosure that a certain feature (“air space”) could be omitted. On the contrary, the reasons for its presence were repeatedly emphasised in the specification. It would not have been possible to recognise the possibility of omitting the feature in question from the application (Point 8). It could be recognised from the facts that the necessity for the feature was associated with a web of statements and explanations in the specification, and that its removal would have required amendments to adjust the disclosure and some of the other features in the case.
5. Nevertheless it is also apparent that in other, perhaps less complicated technical situations, the omission of a feature and thereby the broadening of the scope of the claim may be permissible provided the skilled person could recognise that the problem solving effect could still be obtained without it (e.g. T 151/84 - 3.4.1 of 28 August 1987, unreported). As to the critical question of essentiality in this respect, this is a matter of given feasibility of removal or replacement, as well as the manner of disclosure by the applicant.
6. It is the view of the Board that the replacement or removal of a feature from a claim may not violate Art.123 (2) EPC provided the skilled person would directly and unambiguously recognise that (1) the feature was not explained as essential in the disclosure, (2) it is not, as such, indispensable for the function of the invention in the light of the technical problem it serves to solve, and (3) the replacement or removal requires no real modification of other features to compensate for the change (following the decision in Case T 260/85, OJ EPO 1989, 105). The feature in question may be inessential even if it was incidentally but consistently presented in combination with other features of the invention. Any replacement by another feature must, of course, be examined for support in the usual manner (cf. Guidelines, Part C, Chapter VI, No. 5.4) with regard to added matter.’

[54] Thus the skilled person must be able to recognise directly and unambiguously that (1) the feature is not explained as essential in the original disclosure, (2) it is not, as such, indispensable for the function of the invention in the light of the technical problem it serves to solve, and (3) the replacement or removal requires no real modification of other features to compensate for the change.
[55] This test provides a convenient structured approach to the fundamental question whether, following amendment, the skilled person is presented with information about the invention which is not derivable directly and unambiguously from the original disclosure.
[56] Turning to intermediate generalisation, this occurs when a feature is taken from a specific embodiment, stripped of its context and then introduced into the claim in circumstances where it would not be apparent to the skilled person that it has any general applicability to the invention.
[57] Particular care must be taken when a claim is restricted to some but not all of the features of a preferred embodiment, as the TBA explained in decision T 0025/03 at point 3.3:

'According to the established case law of the boards of appeal, if a claim is restricted to a preferred embodiment, it is normally not admissible under Article 123 (2) EPC to extract isolated features from a set of features which have originally been disclosed in combination for that embodiment. Such kind of amendment would only be justified in the absence of any clearly recognisable functional or structural relationship among said features (see e.g. T 1067/97, point 2.1.3).'

[58] So also, in decision T 0284/94 the TBA explained at points 2.1.3–2.1.5 that a careful examination is necessary to establish whether the incorporation into a claim of isolated technical features, having a literal basis of disclosure but in a specific technical context, results in a combination of technical features which is clearly derivable from the application as filed, and the technical function of which contributes to the solution of a recognisable problem. Moreover, it must be clear beyond doubt that the subject matter of the amended claim provides a complete solution to a technical problem unambiguously recognisable from the application.
[59] It follows that it is not permissible to introduce into a claim a feature taken from a specific embodiment unless the skilled person would understand that the other features of the embodiment are not necessary to carry out the claimed invention. Put another way, it must be apparent to the skilled person that the selected feature is generally applicable to the claimed invention absent the other features of that embodiment.
[60] Ultimately the key question is once again whether the amendment presents the skilled person with new information about the invention which is not directly and unambiguously apparent from the original disclosure. If it does then the amendment is not permissible.”

The judge also reminded myself that the standard is one of clear and unambiguous disclosure. Something that is obvious from the application or might be inferred from it is not good enough.   The relevant comparison is with the application as filed, which in this case was PCT/US2001/14760.

His lordship considered the allegations between para [178] and [184]:

"[178] Both these allegations suffer from the same problem, which is that although the features of the claims of the Patent in question are indeed disclosed in context with other features (respectively, a closed TV cable system, and the detail of the augmented node in the co-pending application), there is no disclosure, either in the passages relied on by Sky, or in the Application as a whole, that those other features are necessary, or that the features all must come as a package for some reason.
[179] Turning to the “individually controlling” feature first, I consider that it is clear that what is important is the information flow from the user to a speech recognition system in the network, processing, and then provision of individualised content. The reader would clearly understand that although the system being referred to is a cable system of a specific kind, the information flow would work with other network types or physical set-ups, and in particular with other return paths. It may be noted, although a minor point overall, that it is merely said at page 9 line 18 that the return path is “often five to 40MHz”.
[180] Furthermore, it is wrong to consider page 9 on its own. There are various other instances in the disclosure where networks other than the traditional closed TV cable network are contemplated. I have addressed them in dealing with the network issue on claim interpretation (I referred to the granted Patent but the same text appears in the Application). The overall teaching is very clearly that an invention is being explained in the context mainly of closed TV cable networks, but not limited to that context.
[181] So there is no added matter in claiming “individually controlling” without also limiting the claim to cable television in a network. Another way of looking at it is that Sky implicitly says the added matter brought in by the claim’s terms is a teaching that it was not necessary to have a closed TV cable network to use the individually controlling feature. But there never was a teaching in the application as filed that it was necessary.
[182] As to the content engine/augmented point, I think the application as filed is clear that an “augmented” node or headend is one where the invention is performed, by which it clearly means that the partitioning of the received back channel takes place - see e.g. claim 1 of the application. This is just to distinguish augmented nodes where that processing is done from nodes which merely pass on data; likewise an augmented headend just means that that processing is done there.
[183] Thus the concept of a node where the key processing takes place is clearly disclosed in the application as filed, and was carried through to claim 1 of it, so there cannot be added matter in that, in itself. I am not sure that Sky really disputed this, hence its further reliance on the description at page 59 of the augmented node being of the particular type described in the co-pending application. But that cannot work as an added matter attack, because page 59 merely says that the augmented node may have those characteristics. It is not added matter thereafter to have a claim which does not require those characteristics.
[184] So I reject the added matter attacks."

Sky contended that the patent was invalid because it did not involve an inventive step as the invention was obvious over United States Patent No, 5,774,859 (“Houser”).  Mr Justice Meade discussed Houser between para [186] and para [198].

His lordship referred to paras [52] to [73] of Lord Hodge's judgment in Actavis v. ICOS [2019] UKSC 15, [2019] Bus LR 1318, [2020] 1 All ER 213, [2019] RPC 9, (2019) 167 BMLR 1 which approved the judgments of the Court of Appeal in Windsurfing International Inc v Tabur Marine (Great Britain) Limited. [1985] RPC 59, [1985] FSR 59 and Pozzoli SPA v BDMO SA [2007] EWCA Civ 588; [2007] FSR 37. In those cases, the Court of Appeal had developed the following methodology for determining whether an invention was obvious:

“(1) (a) Identify the notional ‘person skilled in the art’;
(b) Identify the relevant common general knowledge of that person;
(2) Identify the inventive concept of the claim in question or if that cannot readily be done, construe it;
(3) Identify what, if any, differences exist between the matter cited as forming part of the ‘state of the art’ and the inventive concept of the claim or the claim as construed;
(4) Viewed without any knowledge of the alleged invention as claimed, do those differences constitute steps which would have been obvious to the person skilled in the art or do they require any degree of invention?”

The identification of the skilled addressee in para [13] was very brief, somewhat fuzzy and entwined in a discussion of the merits of the expert witness.  The consensus that seems to have emerged is that the person skilled in the art in this case was a "'decent' engineer who could solve problems."  There was, however, a very extensive discussion of the common general knowledge of such person that spanned para [17] to para [104].  The judge took the second and third Windsurfing/Pozzoli questions together comparing Houser and claim 13 as proposed to be amended (paras [200] to [208]).  In answering the fourth question, his lordship considered Sky's argument at [210] and Promptu's at [212].  He identified the features to initiate communication in the invention and prior art which Promptu had argued would lead down divergent paths and read the transcript to ascertain whether that contention was supported by the expert evidence.  He found that it was not and concluded at [239] "that what Sky proposed was just systematic work: a latency “budget” would have to be prepared, issues such as preparing resources would inevitably be identified, and the appropriate response would be routinely identified."

Further Information
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