Sent by special electronic mailbox for German lawyers
`[beA]
`
`District Court of Mannheim
`- Patent Dispute Chamber -
`A1, 1
`D-68159 Mannheim
`
`Direct service to opponent
`
`In the matter of
`
`JOLED Inc.
`
`versus
`
`Hogan Lovells International LLP
`Kennedydamm 24, 40476 Düsseldorf
`Postfach 32 07 35, 40422 Düsseldorf
`T +49 211 13 68 0
`F +49 211 13 68 100
`www.hoganlovells.com
`
`Dr. Andreas von Falck
`andreas.vonfalck@hoganlovells.com
`D +49 211 13 68-330
`
`Dr. Alexander Klicznik
`alexander.klicznik@hoganlovells.com
`D +49 211 13 68-332
`
`Your reference
`Our reference
`Case no.
`
`2 O 50/20
`1123650
`763439.000001
`
`3 February 2021
`
`REPLY
`
`Attorneys-at-law Dr. Andreas von Falck, Dr. Alexander
`Klicznik, Dr. Roman Würtenberger, Lukas Sievers, Hogan
`Lovells
`International LLP, Kennedydamm 24, 40476
`Düsseldorf
`
`- Plaintiff -
`
`Samsung Electronics GmbH
`
`Taylor Wessing Rechtsanwälte, Munich
`
`- Defendant under 1) -
`
`and
`
`Samsung Electronics Co. Ltd.
`
`Taylor Wessing Rechtsanwälte, Munich
`
`- Defendant under 2) -
`
`Date for hearing: 27 April 2021
`
`Case ref.: 2 O 87/20
`
`Hogan Lovells International LLP ist als Limited Liability Partnership unter OC 323639 in England und Wales registriert. Registersitz: Atlantic House, Holborn Viaduct,
`London EC1A 2FG. Die Zweigniederlassung Düsseldorf ist beim Amtsgericht Essen unter PR 4005 registriert.
`
`"Hogan Lovells" ist eine internationale Anwaltssozietät, zu der Hogan Lovells International LLP und Hogan Lovells US LLP gehören, mit Büros in: Alicante Amsterdam
`Baltimore Birmingham Boston Brüssel Colorado Springs Denver Dubai Düsseldorf Frankfurt am Main Hamburg Hanoi Ho Chi Minh Stadt Hongkong Houston
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`Die Bezeichnung "Partner" beschreibt einen Partner oder ein Mitglied von Hogan Lovells International LLP, Hogan Lovells US LLP oder einer der ihnen nahestehenden
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`Lovells International LLP sind, verfügen nicht über eine Qualifikation, die der von Mitgliedern entspricht. Eine Liste der Mitglieder von Hogan Lovells International LLP steht
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`www.hoganlovells.com.
`
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`we hereby reply
`
`to
`
`the Defendants’ Statement of Defense dated 30 October 2020
`
`(hereinafter: “SoD”) and fully maintain our submissions made so far in their entirety. At the oral
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`- 2 -
`
`hearing we will additionally move for
`
`
`
`
`
`the staying motions of the Defendants under 1) and 2) to be dismissed.
`
`We deny the Defendants’ factual submissions except as expressly acknowledged hereinafter.
`
`
`
`The Complaint is founded. The Defendants’ non-infringement arguments are based on an
`
`incorrect interpretation (see A.). On a correct understanding of the disputed claim features, the
`
`contested embodiments infringe the Patent in Suit (see C.). Contrary to the view taken by the
`
`Defendants, the Patent in Suit is also legally valid (see under D.). A staying of the present
`
`proceeding is therefore excluded.
`
`
`
`Lastly, the Defendants’ submissions on enforcement security are completely unsubstantiated and
`
`do not even remotely justify ordering of enforcement security in the amount of "at least two billion
`
`euros" as requested by the Defendant (see E.).
`
`
`
`
`
`
`
`
`
`A.
`
`Technical background and Patent in Suit
`
`The Defendant’ submissions on the technical background and the interpretation of the Patent in
`
`Suit need to be corrected and supplemented. Particularly Feature 1.3.1 with regard to the
`
`"constant common reference voltage" is interpreted much too narrowly by the Defendants.
`
`However, this is not at all supported by the wording of Claim 1 of the Patent in Suit.
`
`
`
`I.
`
`
`
`The reference voltage
`
`First of all, in reply to the Defendants’ general submissions on the technical background of a
`
`reference voltage in a circuit or a system, the following corrections have to be made.
`
`
`
`1.
`
`A reference voltage or reference potential is not limited to a permanently constant potential.
`
`Systems with variable reference potentials which e.g. may change as a function of a
`
`particular device state are likewise possible and known from a technical standpoint.
`
`
`
`2.
`
`According to the Defendants’ submissions, a reference voltage is "typically" a constant
`
`potential (paragraph 15 SoD). By this open wording, the Defendants themselves already
`
`admit that a reference voltage may also be variable.
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`
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`DUSLIB01//1186155.1
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`Hogan Lovells
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`3.
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`
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`- 3 -
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`This understanding is also confirmed by various examples in the prior art.
`
`
`
`a)
`
`For that we first refer to the US patent application US 2010/0283773 A1, which we
`
`submit as
`
`Exhibit HL-B 8.
`
`
`
`
`
`The rights in this patent application were assigned to the Defendant under 2).
`
`(1) Exhibit HL-B 8 refers to a circuit comprising a reference voltage setup circuit
`
`(cf. Abstract on the title page). This circuit is capable of generating variable
`
`reference voltages.
`
`
`
`(2) The curve of a variable reference voltage Vsource is shown in Figure 6 of Exhibit
`
`HL-B 8, which we insert below:
`
`
`
`
`
`By way of explanation it is stated in this regard in paragraph [0040] of Exhibit
`
`HL-B 8:
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`
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`DUSLIB01//1186155.1
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`FIG. 6 illustrates a schematic diagram of the driving IC of FIG. 5
`including a more detailed schematic diagram of an exemplary
`embodiment of the calibration circuit employable therein and an
`exemplary
`timing diagram of a variable reference voltage
`employable therein;
`
`
`German translation:
`
`FIG. 6 zeigt eine schematische Darstellung des Ansteuer-ICs aus FIG. 5
`einschließlich einer detaillierteren schematischen Darstellung einer
`beispielhaften
`Ausführungsform
`der
`darin
`verwendbaren
`Kalibrierschaltung und eines beispielhaften Zeitdiagramms einer
`darin verwendbaren variablen Referenzspannung;
`
`It is further stated in paragraph [0083]:
`
`In embodiments including the reference voltage generation circuit 190,
`the reference voltage generation circuit 190 may supply the calibration
`circuit 180 with a variable reference voltage Vsource. The variable
`reference voltage Vsource may be employed by the calibration circuit
`180 to determine a voltage level of the test voltage V_RT.
`
`
`German translation:
`
`Referenzspannungs-
`die
`die
`Ausführungsformen,
`In
`Erzeugungsschaltung 190 enthalten, kann die Referenzspannungs-
`Erzeugungsschaltung 190 die Kalibrierschaltung 180 mit einer variablen
`Referenzspannung
`Vsource
`versorgen.
`Die
`variable
`Referenzspannungsquelle Vsource kann von der Kalibrierschaltung 180
`verwendet werden, um einen Spannungspegel der Prüfspannung V_RT
`zu bestimmen.
`
`The circuit shown in Exhibit HL-B 8 thus shows that a reference potential may
`
`easily also be variable and is not a never changing value.
`
`
`
`b) We moreover refer to the US patent US 6 429 841 B1, which we submit as
`
`
`
`
`
`Exhibit HL-B 9.
`
`(1) Exhibit HL-B 9 claims a liquid crystal display apparatus with active matrix.
`
`
`
`(2)
`
`In Figure 8 of Exhibit HL-B 9, which shows the configuration of a liquid crystal
`
`display apparatus according
`
`to an embodiment of
`
`the
`
`invention
`
`in
`
`diagrammatic form, a variable reference voltage generator 24 can be seen:
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`DUSLIB01//1186155.1
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`(3) On the function of the variable reference voltage generator 24 it is then stated
`
`
`
`in column 10, lines 27 ff. of Exhibit HL-B 9:
`
`
`
`Furthermore, the liquid crystal display apparatus includes a variable
`reference voltage generator 24 commonly connected to the reference
`voltage lines CL1 to CLn, a central processing unit(CPU) 20 for
`processing an image data, and a controller 22 connected among the
`CPU 20, the scanning side drive circuit 12 and the data side drive circuit
`14. The variable reference voltage generator 24 applies a reference
`voltage signal commonly to all the n reference voltage lines CL1 to CLn.
`The reference voltage signal generated at the variable reference voltage
`generator 24 changes gradually as shown in FIGS. 9A to 9C as the m
`gate lines GL1 to GLm are sequentially enabled.
`
`
`German translation:
`
`Darüber hinaus enthält die Flüssigkristallanzeigevorrichtung einen
`variablen Referenzspannungsgenerator 24, der gemeinsam mit den
`Referenzspannungsleitungen CL1 bis CLn verbunden ist, eine zentrale
`Verarbeitungseinheit (CPU) 20 zur Verarbeitung von Bilddaten und einen
`Controller 22, der zwischen der CPU 20, der Abtastseiten-
`Treiberschaltung 12 und der Datenseiten-Treiberschaltung 14
`angeschlossen ist. Der variable Referenzspannungsgenerator 24 legt ein
`Referenzspannungssignal
`gemeinsam
`an
`alle
`n
`Referenzspannungsleitungen CL1 bis CLn an. Das am variablen
`Referenzspannungsgenerator 24 erzeugte Referenzspannungssignal
`ändert sich allmählich, wie in FIG. 9A bis 9C gezeigt, wenn die m Gate-
`Leitungen GL1 bis GLm sequentiell aktiviert werden.
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`Hogan Lovells
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`DUSLIB01//1186155.1
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`- 6 -
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`In view of the examples shown from the prior art, there can be no doubt that variable
`
`reference voltages were known to the person skilled in the art.
`
`
`4.
`
`
`
`II.
`
`Feature 1.3.1
`
`
`
`
`
`each pixel includes an EL device (15) including an anode terminal and a
`cathode terminal, the cathode terminal being connected directly to a
`constant common reference voltage;
`
`1.
`
`The reference voltage within the meaning of Feature 1.3.1 is a reference voltage from the
`
`perspective of the display screen (50) or the pixel circuits contained in the display screen
`
`(50). That is because Claim 1 relates to an electroluminescent display apparatus
`
`comprising a display screen (50) in turn comprising a plurality of pixels with circuits. The EL
`
`devices (15) in the pixels are to be connected to a constant common reference voltage
`
`(more precisely: the cathode terminals of the EL devices (15)). For that reason the
`
`perspective of the pixel circuits are to be regarded as decisive when Feature 1.3.1 refers to
`
`the reference voltage.
`
`
`
`2.
`
`In the Defendants’ view, use of the term "constant" in the claim wording shows that it is
`
`solely a reference voltage that is always unchanging that can be claim-compliant. However,
`
`the arguments cited by the Defendants in this regard are unconvincing.
`
`
`
`a)
`
`The Defendants submit that the term "constant", according to general language
`
`usage, refers to an invariable, permanently constant value. To this is has to be
`
`answered firstly that not only a variable or a value may be "constant". For example, a
`
`particular state can also be referred to as constant, and such state may be easily be
`
`constant only for a particular period of time. Secondly, it is inconsistent with an
`
`objective claim interpretation anyway to simply rely on the (apparent) literal meaning
`
`of the linguistic terms used in the claim wording. Rather, it has to be inquired what
`
`the overall technical context is and what function individual features have in
`
`achieving the solution according to the invention. In the first official headnote of the
`
`Decision Spannschraube (BGH GRUR 1999, 909) it is stated:
`
`
`
`
`
`1. The interpretation of a European patent must not cling to the wording
`but be based on the overall technical context which the content of the
`patent specification conveys to the person skilled in the art. It is not the
`linguistic or logical-scientific definition of the terms used in the patent
`specification that is decisive, but rather the understanding of the
`unbiased person skilled in the art.
`
`What is therefore decisive is the overall technical and thus precisely also functional
`
`relationship of the features contained in the patent claim.
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`DUSLIB01//1186155.1
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`b)
`
`In this context it is clear that for achieving the invention-compliant solution here it
`
`does not matter that the common reference voltage is an always unchanging value.
`
`There is no evidence to support this in the Patent in Suit either. The Patent in Suit
`
`solves the problem presented to it of wear on organic light emitting diodes due to the
`
`occurrence of space charge (in this regard cf. 74 ff. of the Statement of Complaint) by
`
`providing each and every pixel circuit in the display panel with a reverse bias voltage
`
`line and a third switch transistor for supplying a reverse bias voltage at the anode
`
`terminal of the EL device (which moreover is not disputed by the Defendants with
`
`respect to the contested embodiments, see section B. below). This effect is achieved
`
`when the common reference voltage is variable. Against this background it is a
`
`nonsensical interpretation to regard – as the Defendants do – exclusively an always
`
`invariable reference voltage as claim-compliant. This is also supported by the fact
`
`that the claim wording is open and precisely does not require the reference voltage to
`
`be constant for an endlessly long period (= always). Rather, those designs are also
`
`precisely covered in which the reference voltage is constant only during a certain
`
`time. The unbiased person skilled in the art who combines the individual features of
`
`the patent claim into something into a sensible whole recognises here that for
`
`achieving the invention-compliant solution such a narrow understanding of the
`
`feature "constant reference voltage" is not decisive.
`
`
`
`c)
`
`For that reason, Feature 1.3.1 also mentions "a" constant common reference voltage.
`
`Here, in contrast to Feature 1.5 (more on that later), an indefinite article is used
`
`because it is precisely not a certain, permanently constant voltage that is decisive.
`
`
`
`d)
`
`It is simply irrelevant that the Patent in Suit, to which the Defendants refer in
`
`paragraph 15 SoD, uses the term "constant" in paragraphs [0327] and [0346]
`
`apparently for fixed values. That is because in said passages this term is used in a
`
`completely different context and therefore also does not allow any conclusions as to
`
`the correct understanding of Feature 1.3.1. Both paragraphs [0327] and [0346] are
`
`concerned with a time period that has a fixed value, i.e. that is to be just as long each
`
`time. The relationships described there have nothing to do with the device described
`
`in Claim 1 of the Patent in Suit and in particular with the reference voltage, and
`
`therefore cannot be cited for the interpretation of this feature either.
`
`
`
`e)
`
`The Defendants further allege that the Plaintiff in the grant procedure itself had
`
`adopted an understanding that the reference voltage at the cathode terminal of the
`
`EL devices was an absolutely unchangeable value. In this regard it refers to a
`
`submission by the Plaintiff made as part of Exhibit TW1 to the European Patent
`
`Office of 15 February 2019 and cites – albeit without context – a single sentence on
`
`page 7 of such submission. In this submission the Plaintiff commented on the
`
`European Search Report dated 31 October 2018 in which Claim 1 in the filed version
`
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`DUSLIB01//1186155.1
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`- 8 -
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`was seen as being made obvious by document D1 in combination with document D2.
`
`The Plaintiff then submitted an adapted claim version and explained why it was not
`
`made obvious. Cited in full, the paragraph in question on page 7 of Exhibit TW 1
`
`reads as follows:
`
`
`
`In contrast to D2, new claim 1 requires that the cathode terminal of the
`EL device is connected to a constant common reference voltage. Thus,
`when transitioning from the reverse biasing period to the light emission
`period, only the anode terminal voltage of the EL device changes.
`Especially, the cathode terminal voltage of the EL device, which is
`common for all pixels, is fixed without change. Consequently, the
`claimed invention makes possible to achieve a stable light emission.
`
`
`German translation:
`
`Im Gegensatz zu D2 erfordert der neue Anspruch 1, dass der
`Kathodenanschluss der EL-Einrichtung an eine konstante gemeinsame
`Referenzspannung angeschlossen ist. Daher ändert sich beim Übergang
`von der Sperrvorspannperiode zur Lichtemissionsperiode nur die
`Anodenspannung der EL-Einrichtung. Insbesondere die Spannung am
`Kathodenanschluss der EL-Einrichtung, die allen Pixeln gemeinsam
`ist, bleibt unverändert. Folglich ermöglicht es die beanspruchte
`Erfindung, eine stabile Lichtemission zu erreichen.
`
`
`
`f)
`
`The sentence highlighted in the above quote thus only expresses that the reference
`
`voltage at the cathode terminal remains the same both in the reverse biasing period
`
`and in the lighting state period. In this phase, i.e. in the transition from the reverse
`
`biasing period to the lighting state period, the cathode potential is not to change. In
`
`claim-compliant embodiments this is not required either, since in them each pixel
`
`circuit is provided with a reverse bias voltage line and a third switch transistor to
`
`supply a reverse bias voltage to the anode terminal of the EL device. For the
`
`operation of reverse biasing it is therefore not required that the cathode voltage
`
`changes. The Patent in Suit is therefore distinguished decisively from document D2
`
`and also explains why Features 1.3.1, 1.4 and 1.5 were incorporated in Claim 1 in
`
`their current form. In the pixel circuit according to Figure 5 of document D2 the
`
`cathode voltage changes between the reverse biasing period and the lighting state
`
`period, as can be seen from the representation on page 7 of Exhibit TW1. Moreover,
`
`in the device according to document D2 there is no common cathode terminal over
`
`which all cathode terminals of the EL devices are supplied with the same voltage in
`
`the pixel matrix. A cathode voltage changing between the reverse biasing and
`
`lighting state period results in a less stable light emission since the light emission
`
`intensity at the diode (i.e. the OLED) is a function of anode-to-cathode voltage. If the
`
`cathode voltage changes, the light emission intensity thus also changes. In the
`
`transition from the reverse biasing period to the lighting state period, however, this is
`
`precisely, according to the teaching of the Patent in Suit, to be avoided to obtain a
`
`stable light emission. That is because the technical advantage of providing a reverse
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`DUSLIB01//1186155.1
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`- 9 -
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`bias voltage line for each pixel circuit for supplying a bias voltage and thus extending
`
`the life of the organic light emitting diode (in this regard cf. p. 74 ff. of the Statement
`
`of Complaint) is not to be achieved at the expense of a qualitatively inferior image
`
`display.
`
`
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`g)
`
`This understanding according to which "constant" merely means that in the reverse
`
`biasing period and the lighting state period the same cathode voltage is present is
`
`also confirmed by Feature 1.5 of Claim 1 of the Patent in Suit where it is stated:
`
`
`
`
`
`wherein both during the reverse biasing period and during a lighting
`state period of the EL device (15), the constant common reference
`voltage is supplied to the cathode terminal of the EL device (15).
`
`By this it is thus clarified that in both periods the cathode terminal of the EL device is
`
`supplied "the" (here, unlike in Feature 1.3.1, a definite article is used, i.e. a particular
`
`voltage is meant) constant common reference voltage. However, it does not follow
`
`from that at the same time that the reference voltage is a value that is unchangeable
`
`at any time. As shown, this is neither technically imperative nor required for achieving
`
`the result according to the invention.
`
`B.
`
`Infringement of Patent in Suit
`
`
`
`
`
`
`
`
`
`
`
`The Defendants merely dispute the realisation of Features 1.3.1 and 1.5 of Claim 1 of the Patent
`
`in Suit. However, the Defendants’ argumentation in this regard is based on a flawed interpretation
`
`of the Patent in Suit, as already shown in section B. above. In actual aspects, the attacked
`
`embodiments feature all of the components of the device recited in the claim. On a correct view,
`
`the contested embodiments also realise Features 1.3.1 and 1.5.
`
`Feature 1.3.1
`
`
`
`I.
`
`
`
`
`
`each pixel includes an EL device (15) including an anode terminal and a
`cathode terminal, the cathode terminal being connected directly to a
`constant common reference voltage;
`
`1.
`
`Reference voltage
`
`
`
`The cathode terminals of the EL devices in the pixels of the contested embodiments are
`
`connected to a reference voltage.
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`DUSLIB01//1186155.1
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`a)
`
`The Defendants allege that the potential at the cathode terminal in the contested
`
`embodiments was not a reference voltage within the meaning of Feature 1.3.1. In
`
`support of this view, they submit that the cathode terminals are supplied with voltage
`
`via what is known as a power management chip (PMIC) and that the PMIC in turn
`
`referred to an electric ground found outside the PMIC.
`
`
`
`b)
`
`This is unconvincing. The cathode terminals of all EL devices in the pixel matrix
`
`within the screen of the contested embodiments are indisputably connected to a
`
`common cathode sheet or "cathode plate" (cf. paragraph 26 SoD), referred to by the
`
`Defendants also as "conductive layer" (cf. paragraph 33 SoD). This cathode plate
`
`extends over the entire screen since it forms a common return conductor for all EL
`
`devices. From the perspective of the screen (50) of the pixel circuits contained in the
`
`screen, the potential of the cathode plate represents the (common) reference
`
`potential. For the screen (50), this common cathode plate represents the "housing".
`
`This is comparable to the consumers in a car, all of which use the body or frame as a
`
`return conductor for minus pole of the battery. The frame in this regard forms the
`
`common reference potential and to each consumer only one separate line has to be
`
`laid. It is no different in the pixel matrix in the contested embodiments.
`
`
`
`c)
`
`The cathode plate those has exactly those properties to which the Defendants
`
`themselves attribute to the electric ground when they submit in paragraph 12 SoD:
`
`
`
`
`
`The electric ground may therefore always correspond to the always
`constant potential of zero. It may be attributed to a point in the circuit
`which is connected electrically to ground, i.e. to the potential of the
`conductive ground. It may likewise be attributed to a point which is
`connected to an object such as a grounding surface or a housing
`possessing the properties of the ground to an at least sufficiently
`good extent, i.e. can absorb or give up or donate electrons without
`its own potential noticeably changing. Such points may represent the
`reference potential for all operating and signal voltage within a system.
`
`Said cathode plate is nothing other than such grounding surface (a "housing") for the
`
`screen. It represents the reference potential for the operating and signal voltages of
`
`the pixel circuits whose perspective, as shown, is decisive here. The fact that what
`
`the Patent in Suit means by reference is such grounding surface that simulates the
`
`ground potential is also seen from the common symbol, used for example in Fig. 47
`
`of the Patent in Suit – showing a claim-compliant pixel circuit –, for electrical (device)
`
`ground, with the common potential Vk being present here:
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`DUSLIB01//1186155.1
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`This symbol for electric ground is used primarily in circuits of electrical devices since
`
`these of course (as e.g. a mobile phone) do not have any direct connection to ground
`
`potential. Instead, the frame or simply a grounding surface forms the common
`
`reference point here. In the contested embodiments, this is the common cathode
`
`plate for the screen (50) and the pixel circuits contained therein.
`
`
`
`The diagram shown in the Statement of Complaint on page 107, which shows the
`
`voltage at the cathode at various screen brightnesses (which the Defendants do not
`
`contest in substance), also illustrates that the cathode voltage is the reference
`
`potential for the pixel circuits. That is because at different cathode voltages also the
`
`screen brightness is different. However, adjusting the cathode voltage is not the only
`
`way in which the screen brightness is regulated in the attacked embodiments. This
`
`also explains why the cathode voltage in the graph is not proportional to the screen
`
`brightness. Specifically, in the low to medium range (from about 21% to about 43% of
`
`maximum brightness), brightness is adjusted by creating band-shaped non-display
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`regions and band-shaped display regions that are moved down relative to the screen
`
`and by changing the respective proportions of the screen area (more band-shaped
`
`non-display regions = lower brightness). This technique is known to the Board from
`
`the application extension filed on January 28, 2021 in the parallel file number
`
`2 O 50/20 and the EP 3 716 257 B1 asserted therein. If the brightness is adjusted
`
`only or predominantly in this way, the cathode voltage can also remain approximately
`
`the same. In contrast, there are also brightness ranges in which the brightness is
`
`(also) regulated by changing the cathode voltage, i.e. the reference potential. This is
`
`immediately clear since it is on the voltages in the pixel circuit (e.g. the voltage at the
`
`gate of the driving transistor) that the current strength supplied to the EL device is
`
`dependent and it is as a function of this current strength that the EL device lights
`
`strongly or less strongly. To put it differently: if the reference voltage changes at the
`
`cathode terminals, the brightness of the entire screen also changes. This illustrates
`
`that it is the reference potential for the screen.
`
`
`
`2.
`
`Constant reference voltage
`
`
`
`The cathode terminal in the electroluminescence device (15) of a pixel in the contested
`
`embodiment is also connected to a constant common reference voltage.
`
`
`
`
`DUSLIB01//1186155.1
`
`
`
`
`Hogan Lovells
`
`SAMSUNG EX. 1006 - 11/35
`
`

`

`
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`- 12 -
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`a)
`
`The Defendants allege in this connection that the voltage at the cathode terminal
`
`could not be a constant reference voltage because it varied depending on the screen
`
`brightness or state and therefore was unsuitable as a reference voltage.
`
`
`
`b)
`
`As explained in section A., it is already not true that a reference voltage or reference
`
`potential must always be an unchanging value. Instead, it is also conceivable that the
`
`potential – precisely also depending on an operating state – changes. The reference
`
`voltage within the meaning of Feature 1.3.1 is to be constant only in the transition
`
`from the reverse biasing period to the lighting condition period since otherwise a
`
`flickering of the screen would occur (by way of reminder: if the cathode voltage
`
`changes, so too does the light emission intensity.). Also in the contested
`
`embodiments, the reference voltage at the cathode terminal is unchanged during the
`
`reverse biasing period and the lighting state period. According to the Defendants’
`
`own submissions and based on the measurements performed on behalf of the
`
`Plaintiff, the cathode voltage in the contested embodiments changes as a function of
`
`the general screen brightness and the image displayed. In each frame there is a
`
`reverse biasing period followed by a lighting state period (cf. also submissions on
`
`page 112 ff. of the Statement of Complaint), but with the cathode voltage not
`
`changing in both periods. Unlike in pixel switches from the prior art, the reference
`
`potential at the cathode terminal of the EL device in Patent in Suit-compliant
`
`embodiments and thus also in the contested embodiments does not have to be
`
`changed to pole the EL device in reverse direction. This is made possible by a
`
`separate reverse biasing line and the third switch transistor pursuant to Feature 1.3.5
`
`in each pixel circuit. It is therefore a constant reference voltage within the meaning of
`
`Feature 1.3.1. Requirements for such feature going beyond that would not contribute
`
`anything to achieving the invention-compliant solution and are therefore to be
`
`rejected.
`
`
`
`c)
`
`In paragraph 37 of the Statement of Defense, the Defendants allege that the cathode
`
`voltage in contested embodiments with 120 Hz display screens (which thus display
`
`120 images per second) could change "up to" 120 times per second. However, such
`
`frequent changes in the cathode voltage led to fluctuations in the light intensity of the
`
`display image (flickering) and to an non-uniform and poor greyscale rendering on the
`
`display screen. The reason for this is that the cathode terminal indisputably
`
`"common" for the entire display panel in the form of the "cathode plate" (paragraph
`
`36 SoD) and "conductive layer" (paragraph 33 SoD). Changes in the cathode
`
`potential therefore affect the image rendering over the entire screen since the lighting
`
`intensity of the EL devices in the pixels is a function of the anode-to-cathode voltage.
`
`In the case of too frequent or too fast changes in the cathode voltage, then, the
`
`image quality would suffer as a result of flickering and poor greyscale rendering.
`
`Against this background we contest that the cathode voltage in the contested
`
`
`
`DUSLIB01//1186155.1
`
`
`
`
`Hogan Lovells
`
`SAMSUNG EX. 1006 - 12/35
`
`

`

`- 13 -
`
`embodiments changes up to 120 times per second. This is also refuted by the
`
`measurements performed on behalf of the Plaintiff on the contested embodiments
`
`Galaxy S9+. In this regard we once again insert the diagram of the voltage curve at
`
`the cathode terminal:
`
`
`
`
`
`Kathodenspannung
`
`Anodenspannung
`
`
`
`In a range of approx. 21% to 43% of full brightness, it can be seen here (highlighted
`
`by this side by the black box) that the cathode voltage is unchanged in the case of a
`
`bright image. From about 21% to about 29% of the full brightness an identical,
`
`constant cathode voltage is present both for a bright image and a dark image. This
`
`shows that the cathode voltage does not necessarily have to change also in different
`
`operating states. In this respect, we refer to further options for regulating the screen
`
`brightness, as presented above in section B.I.1.d).
`
`
`
`The Defendants’ argument that the cathode voltage in the contested embodiments
`
`fluctuated too strongly and therefore could not represent a reference potential is
`
`therefore uncompelling.
`
`
`
`
`
`3.
`
`Direct connection
`
`
`
`The cathode terminal in a pixel circuit of the contested embodiments is lastly connected to
`
`a constant common reference voltage.
`
`
`
`a)
`
`As stated, the voltage at the cathode terminal is the common reference potential. The
`
`cathode terminals of the EL devices in the pixels are indisputably connected to a
`
`common cathode plate or "conductive layer" that leads to the PMIC.
`
`
`
`DUSLIB01//1186155.1
`
`
`
`
`Hogan Lovells
`
`SAMSUNG EX. 1006 - 13/35
`
`

`

`
`
`
`
`- 14 -
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`b)
`
`This represents a direct connection to the constant common reference voltage since
`
`no switches or similar components are present between the terminals.
`
`
`
`c)
`
`The supply of a voltage to the anode or cathode connection via DCDC converters,
`
`which for example appropriately convert a battery voltage, is furthermore clearly
`
`provided for in the Patent in Suit. In paragraph [0052] of Exhibit HL-B 2 it is stated:
`
`
`
`[0052] To feed the anode or cathode wiring with a high current, a power
`wire for supply of a power having a low current and a high voltage is
`routed from current feeding means to a location in the vicinity of the
`anode wiring or the like and the power is converted into a power having a
`low voltage and a high current with a DCDC converter or the like before
`being fed to the anode wiring or the like. That is, a high-voltage and low-
`current wire is routed from the p