UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`SAMSUNG DISPLAY CO., LTD.,
`SAMSUNG ELECTRONICS CO., LTD., and
`SAMSUNG ELECTRONICS AMERICA, INC.,
`Petitioners,
`
`v.
`
`SOLAS OLED LTD.,
`Patent Owner.
`____________
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`____________
`
`EXPERT DECLARATION OF THOMAS CREDELLE
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 1
`
`
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`SAMSUNG DISPLAY CO., LTD.,
`SAMSUNG ELECTRONICS CO., LTD., and
`SAMSUNG ELECTRONICS AMERICA, INC.,
`Petitioners,
`
`v.
`
`SOLAS OLED LTD.,
`Patent Owner.
`____________
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`____________
`
`EXPERT DECLARATION OF THOMAS CREDELLE
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 1
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`TABLE OF CONTENTS
`
`BACKGROUND .................................................................... 1
`I.
`EDUCATIONAL AND EMPLOYMENT BACKGROUND ....... 1
`II.
`III. MATERIALS CONSIDERED ................................................. 6
`IV. RELEVANT LEGAL STANDARDS FOR ANTICIPATION
`AND OBVIOUSNESS ............................................................ 8
`A.
`Burden of Proof ............................................................................... 8
`B.
`Claim Construction ......................................................................... 8
`Anticipation ..................................................................................... 9
`C.
`D. Obviousness .................................................................................. 10
`V.
`LEVEL OF ORDINARY SKILL IN THE ART ....................... 11
`VI. BACKGROUND FOR THE ’880 PATENT ............................ 13
`A.
`Flat Panel Displays ........................................................................ 13
`Active matrix TFT arrays .............................................................. 15
`B.
`C.
` ....................................................................................................... 16
`1.
`OLED light emission ............................................................... 16
`2.
`OLED circuit considerations .................................................... 17
`VII. OVERVIEW OF THE ’880 PATENT ..................................... 19
`Background of the '880 Patent ...................................................... 19
`A.
`Elements of the '880 patent ........................................................... 20
`B.
`
`Active-matrix Organic Light-Emitting Diode ("OLED") Displays
`
`i
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 2
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`
`Display Apparatus with Expanded Control .............................. 20
`1.
`Drive transistor and Storage Capacitor Reset .......................... 25
`2.
`C.
`The Prosecution History of the ’880 patent .................................. 28
`VIII. CLAIM CONSTRUCTION ................................................... 28
`IX. LACK OF ANTICIPATION OR OBVIOUSNESS .................. 29
`A. Grounds 1/1a: Miyazawa (Claims 1–9, 11–14, and 25–32) .......... 29
`B.
`Grounds 2/2a: Morosawa (Claims 1–14 and 25–33) .................... 49
`C.
`and 34–40) ..................................................................................... 86
`D. Ground 4: combination of Morosawa, Shirasaki, and Koyama
`(Claims 24 and 40) ........................................................................ 93
`E.
` ....................................................................................................... 95
`X. CONCLUSION .................................................................... 97
`
`Ground 3: combination of Morosawa and Shirasaki (Claims 18–24
`
`Ground 5: combination of Morosawa and Hector (Claims 15–17)
`
`
`
`ii
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 3
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`I.
`BACKGROUND
`
`1.
`
`I have been retained by Patent Owner Solas OLED Ltd. (“Solas” or
`
`“Patent Owner”) to provide my opinions with respect to their Response to the
`
`Petition for Inter Partes Review in IPR2021-00591 (“Petition”) as to U.S. Pa-
`
`tent No. 7,868,880 (“’880 patent,” Exhibit 1001), brought by Petitioners Sam-
`
`sung Display Co., Ltd., Samsung Electronics Co., Ltd., and Samsung
`
`Electronics America, Inc. (“Samsung” or “Petitioners”). I have no interest in
`
`the outcome of this proceeding and my compensation is in no way contingent
`
`on my providing any particular opinions.
`
`2.
`
`As a part of this engagement, I have also been asked to provide my
`
`technical review, analysis, insights, and opinions regarding the Petition and
`
`the supporting declaration of Dr. Miltiadis Hatalis (“Hatalis Declaration” or
`
`Ex. 1003) with respect to the challenged claims of the ’880 patent.
`
`3.
`
`The statements made herein are based on my own knowledge and opin-
`
`ions.
`
`II. EDUCATIONAL AND EMPLOYMENT BACKGROUND
`
`4. My complete qualifications and professional experience are described
`
`in my Curriculum Vitae, a copy of which can be found in Ex. 2002. The fol-
`
`lowing is a brief summary of my relevant qualifications and professional ex-
`
`perience.
`
`1
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 4
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`5.
`As shown in my curriculum vitae, I have devoted my career to the re-
`
`search and development and product engineering of flat panel displays and
`
`materials/optics/electronics for flat panel displays and touch sensors. I have
`
`over 20 years of involvement in active matrix LCD R&D, starting in 1983 at
`
`RCA Labs and continuing at GE. I led the product development of active ma-
`
`trix LCDs for notebook computers at Apple in the early 90’s and had close
`
`collaboration with many LCD developers in Asia. Later in my career, I made
`
`significant contributions to the design and implementation of new pixel archi-
`
`tectures for LCDs and OLEDs while at Clairvoyante; both efforts involved
`
`TFT design modifications to achieve the desired goals of high pixel transmis-
`
`sion and reduced circuit complexity. More recently, I have been involved in
`
`several patent litigation cases which required a detailed knowledge of TFT
`
`design, materials, and processing.
`
`6.
`
`I am currently the President of TLC Display Consulting and split my
`
`time between technical consulting and patent litigation support.
`
`7.
`
`I received my M.S. degree in Electrical Engineering from the Massa-
`
`chusetts Institute of Technology in 1970, with an emphasis on Electro Optics
`
`and Solid-State Materials. I received my B.S. degree in Electrical Engineering
`
`in 1969 from Drexel University.
`
`2
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 5
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`8.
`I was employed by RCA at Sarnoff Labs in Princeton, NJ from 1970
`
`through 1986 at first as a Member of the technical Staff and later as a Group
`
`Manager in charge of all Active Matrix LCD research. During my time at
`
`RCA, I participated in research and development projects relating to optical
`
`materials and flat panel displays, including LCD devices. In 1983, I estab-
`
`lished the Thin Film Transistor (“TFT”) LCD Program at Sarnoff Labs. As a
`
`Group Manager, I led a project that resulted in the development of the first
`
`poly silicon TFT LCD at Sarnoff Labs. I received the Sarnoff Outstanding
`
`Achievement Award for Large Area Flat Panel TV Developments.
`
`9.
`
`From 1986 to 1991, I was employed by GE as the Manager of TFT LCD
`
`Research and Development at the GE Research and Development Center in
`
`Schenectady, NY. My duties included contributing to and managing research
`
`and development efforts relating to TFT and LCD technology for avionics
`
`applications. While employed by GE, I led the team that built the world’s first
`
`1-million-pixel color LCD device. I also led development of numerous other
`
`display devices utilizing LCD technology.
`
`10. From 1991 to 1994, I was employed by Apple Computer as the Man-
`
`ager of Display Engineering. In my role at Apple, I supervised all TFT-LCD
`
`design (in-house and at vendors), engineering, and qualification for the first
`
`PowerBook notebook computers introduced to market in the United States. A
`
`3
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 6
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`key part of my effort was the evaluation and development of active matrix
`
`LCDs with improved performance, such as viewing angle, contrast ratio and
`
`uniformity.
`
`11. From 1994 to 1996, I was employed as the Director of Advanced Prod-
`
`uct Marketing by Allied Signal, where I was involved with the design and
`
`engineering of optical films and custom focusing backlight designs for im-
`
`proving the viewing angle performance of LCD devices.
`
`12. From 1996 to 1999, I was employed as the Director of Product Market-
`
`ing for Motorola’s Flat Panel Display Division, where I worked in the devel-
`
`opment of new flat panel technology, and I also worked closely with Motorola
`
`groups responsible for integrating TFT-LCD technology into mobile phone
`
`products.
`
`13. From 1999 to 2001, I served as the Vice President of Operations of Al-
`
`ien Technology Corporation. During my time at Alien Technology, I was in-
`
`volved with the design and architecture of drive electronics packaging
`
`technology suitable for flexible display devices.
`
`14. From 2001 to 2007, I served as the Vice President of Engineering for
`
`Clairvoyante, Inc. My responsibilities as the VP of Engineering included man-
`
`aging research, development, engineering, and marketing of technologies for
`
`improving the resolution and power consumption of color flat panel displays,
`
`4
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 7
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`which required significant changes to the active matrix layout. During my
`
`time at Clairvoyante, I was therefore heavily involved with the design of the
`
`active matrix array and the LCD or OLED driving circuitry. My work resulted
`
`in the issuance of multiple patents relating to TFT-LCD and TFT-OLED dis-
`
`play technology.
`
`15. From 2007 to 2008, I served as the Senior VP of Engineering for Pure-
`
`depth, Inc. My responsibilities included the design of hardware and software
`
`to create 3D images on TFT-LCDs.
`
`16. From 2012 through 2015, I served as the Vice President of Application
`
`Engineering and Device Performance for Innova Dynamics, Inc., a nanotech-
`
`nology company developing materials to be used in LCDs and touch sensors.
`
`In that effort, I led the collaboration with major capacitive touch sensor mak-
`
`ers to replace brittle Indium Tin Oxide (“ITO”) transparent conductors with
`
`silver nanowire conductors, which are compatible with flexible touch sensors.
`
`We successfully fabricated flexible capacitive touch sensors that could be bent
`
`without breaking.
`
`17.
`
`In 2008, I founded TLC Display Consulting, a company that provides
`
`technical consulting in the areas of flat panel displays, liquid crystal displays,
`
`OLED, touch sensors, LEDs, and related electronics. I currently serve as the
`
`President of TLC Display Consulting.
`
`5
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 8
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`18.
`I have been an active member of the Society for Information Display
`
`(“SID”) for over 40 years, having attended every SID Annual Technical Sym-
`
`posium since 1972. I was a member of the Society for Information Display’s
`
`Program Committee for 15 years, and the Director of the Society for Infor-
`
`mation Display’s Symposium Committee for 10 years. In 1984, I was awarded
`
`the title of Fellow of the Society for Information Display in recognition of my
`
`achievements and contributions to flat panel display technology.
`
`19.
`
`I am a named inventor on over 80 US patents relating to flat panel dis-
`
`play, LCD, and OLED technology. I have also authored several articles relat-
`
`ing to LCD technology and flat panel displays that were published by industry
`
`periodicals such as Information Display and peer reviewed journals such as
`
`the Society for Information Display’s Digest of Technical Papers.
`
`III. MATERIALS CONSIDERED
`
`20.
`
`I have been asked to provide a technical review, analysis, insights, and
`
`opinions. My technical review, analysis, insights, and opinions are based on
`
`my education, research, and experience, as well as my study of relevant ma-
`
`terials.
`
`21.
`
`I have reviewed and am familiar with the ’880 patent specification and
`
`claims. (Ex. 1001) My understanding of the claims is based on the plain and
`
`6
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 9
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`ordinary meaning of the claims as would be understood by a person of ordi-
`
`nary skill in the art, unless the inventor has provided a special meaning for a
`
`term. Unless otherwise noted, my opinions set forth herein do not rest on a
`
`disagreement with Dr. Hatalis as to the meaning of any claim term or limita-
`
`tion.
`
`22.
`
`I have reviewed and am familiar with the Petition for Inter Partes Re-
`
`view and the Board’s Decision to Institute in this proceeding.
`
`23.
`
`I have reviewed the Declaration of Dr. Miltiadis Hatalis (Ex. 1003) and
`
`the transcript of his deposition in this IPR (Ex. 2003). I have also reviewed
`
`the Miyazawa (Ex. 1006), Morosawa (Ex. 1008), Shirasaki (Ex. 1009)1, Ko-
`
`yama (Ex. 1011), and Hector (Ex. 1010) references submitted by Petitioner in
`
`this proceeding, as well as other references, and am familiar with those refer-
`
`ences. I have also reviewed the prosecution history of the ’880 patent.
`
`24.
`
`I have previously offered opinions concerning the ’880 patent in U.S.
`
`International Trade Commission proceeding In the matter of Certain Active
`
`Matrix OLED Display Devices and Components Thereof, Investigation No.
`
`
`1 I am informed that as Exhibits 1008 and 1009, Samsung initially submitted
`the international search reports of these patent applications, not the published
`applications themselves. I understand that Samsung subsequently submitted
`replacement copies of Exhibits 1008 and 1009. Unless otherwise stated, my
`opinions concerning Exhibits 1008 and 1009 are based upon the replacement
`versions of these exhibits.
`
`7
`
`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 10
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`337-TA-1243. In preparing this declaration, I have considered the Order Con-
`
`struing Terms of the Asserted Claims, dated August 4, 2021, issued by the
`
`Administrative Law Judge in that Proceeding. (Ex. 2004).
`
`25. This declaration represents only opinions I have formed to date. I may
`
`consider additional documents as they become available or other documents
`
`that are necessary to form my opinions. I reserve the right to revise, supple-
`
`ment, or amend my opinions based on new information and on my continuing
`
`analysis.
`
`IV. RELEVANT LEGAL STANDARDS FOR ANTICIPATION
`AND OBVIOUSNESS
`
`26.
`
`I am not an attorney. I offer no opinions on the law. But counsel has
`
`informed me of the following legal standards relevant to my analysis here. I
`
`have applied these standards in arriving at my conclusions.
`
`A. Burden of Proof
`
`27.
`
`I understand that in an inter partes review the petitioner has the burden
`
`of proving a proposition of unpatentability by a preponderance of the evi-
`
`dence.
`
`B. Claim Construction
`
`28.
`
`I understand that the Board will apply the “plain and ordinary meaning”
`
`standard to claim construction in this proceeding. I understand that the plain
`
`and ordinary meaning of a claim term is the meaning that the term would have
`
`8
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 11
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`
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`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`to a person of ordinary skill in the art in question at the time of the invention
`
`when read in view of the patent claims and the specification.
`
`29.
`
`I understand that the Board does not construe claim terms unnecessary
`
`to resolving the controversy.
`
`C. Anticipation
`
`30.
`
`I understand that for a prior art reference to serve as an anticipatory
`
`reference, it must disclose every limitation of the claimed invention, either
`
`explicitly or inherently. I further understand that unless a reference discloses
`
`within the four corners of the document not only all of the limitations claimed
`
`but also all of the limitations arranged or combined in the same way as recited
`
`in the claim, it cannot be said to prove prior invention of the thing claimed.
`
`31.
`
`I further understand that to be anticipatory, the prior art reference must
`
`provide an enabling disclosure of the claimed invention. I further understand
`
`that prior art references that are ambiguous as to the presence or description
`
`of a particular claim element cannot anticipate a claim.
`
`32.
`
`I further understand anticipation does not permit a patent challenger to
`
`“fill in” missing limitations not disclosed in the reference, by arguing that one
`
`of skill in the art would at once envision using the missing limitation.
`
`33.
`
`I further understand that in an anticipation analysis, the use of extrinsic
`
`evidence, such as expert testimony and publications, is necessarily of limited
`
`9
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 12
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`scope and probative value, for a finding of anticipation requires that all aspects
`
`of the claimed invention were already described in a single reference: a find-
`
`ing that is not supportable if it is necessary to prove facts beyond those dis-
`
`closed in the reference in order to meet the claim limitations. I further
`
`understand that the role of extrinsic evidence is to educate the fact finder re-
`
`garding the technology, not to fill gaps in the reference. I further understand
`
`that if it is necessary to reach beyond the boundaries of a single reference to
`
`provide missing disclosure of the claimed invention, the proper ground is not
`
`anticipation, but obviousness.
`
`D. Obviousness
`
`34.
`
`I understand that a claim of a patent may not be novel even though the
`
`invention is not identically disclosed or described in the prior art so long as
`
`the differences between the subject matter sought to be patented and the prior
`
`art are such that the subject matter as a whole would have been obvious to a
`
`person having ordinary skill in the art in the relevant subject matter at the time
`
`the invention was made.
`
`35.
`
`I understand that, to demonstrate obviousness, it is not sufficient for a
`
`petition to merely show that all of the elements of the claims at issue are found
`
`in separate prior art references or even scattered across different embodiments
`
`10
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 13
`
`
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`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`and teachings of a single reference. The petition must thus go further, to ex-
`
`plain how a person of ordinary skill would combine specific prior art refer-
`
`ences or teachings, which combinations of elements in specific references
`
`would yield a predictable result, and how any specific combination would op-
`
`erate or read on the claims. Similarly, it is not sufficient to allege that the prior
`
`art could be combined, but rather, the petition must show why and how a per-
`
`son of ordinary skill would have combined them.
`
`36.
`
`I understand that, to demonstrate obviousness, a petition must accu-
`
`rately identify and analyze the differences between the claimed invention and
`
`the prior art.
`
`37.
`
`I understand that obviousness cannot be shown by conclusory state-
`
`ments, and that the petition must provide articulated reasoning with some ra-
`
`tional underpinning to support its conclusion of obviousness.
`
`V. LEVEL OF ORDINARY SKILL IN THE ART
`
`38.
`
`I understand there are multiple factors relevant to determining the level
`
`of ordinary skill in the pertinent art, including (1) the levels of education and
`
`experience of persons working in the field at the time of the invention; (2) the
`
`sophistication of the technology; (3) the types of problems encountered in the
`
`field; and (4) the prior art solutions to those problems.
`
`11
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 14
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`
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`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`39.
`I am familiar with OLEDs (including those with thin-film transistors
`
`(“TFTs”)) and how they are manufactured. I am also aware of the state of the
`
`art at the time the application resulting in the ’880 patent was filed. I under-
`
`stand that the earliest priority date for the ’880 patent is May 24, 2005.
`
`40. Dr. Hatalis offers the opinion that a person of ordinary skill in the art
`
`for the ’880 patent in 2005 “would have had at least a bachelor’s degree in
`
`electrical engineering (or equivalent) and at least two years’ industry experi-
`
`ence, or equivalent research in circuit design” and that “a POSA could substi-
`
`tute directly relevant additional education for experience, e.g., an advanced
`
`degree relating to the design of electroluminescent devices, drive circuits, or
`
`other circuit design or an advance degree in electrical engineering (or equiv-
`
`alent), with at least one year of industry experience.” (Ex. 1003, ¶ 35.)
`
`41.
`
`In the ITC proceeding involving the ’880 patent, the Administrative
`
`Law Judge adopted the following definition of a person of ordinary skill in
`
`the art: “an ordinary artisan in the field of the asserted patents would likely
`
`have at least a bachelor’s degree in electrical engineering and approximately
`
`two years of either industry or equivalent research experience in the areas of
`
`circuit design and/or optical display technologies.” (Ex. 2004 at 8.)
`
`12
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 15
`
`
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`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`42. For the purposes of this declaration, I assume that Dr. Hatalis’s defini-
`
`tion of the person of ordinary skill in the art is correct. I note that this defini-
`
`tion is similar to the definition adopted by the ITC ALJ, and my opinions in
`
`this declaration would not change if I adopted the ALJ’s definition rather than
`
`Dr. Hatalis’s.
`
`43. Based on these criteria of a person of ordinary skill, as of the relevant
`
`time frame for the ’880 patent, I possessed at least such experience and
`
`knowledge of a POSITA, hence am qualified to opine on validity of this pa-
`
`tent. For purposes of this declaration, in general, and unless otherwise noted,
`
`my statements and opinions, such as those regarding my experience and the
`
`understanding of a POSITA generally (and specifically related to the refer-
`
`ences I consulted herein), reflect the knowledge that existed in the field as of
`
`May 24, 2005. Unless otherwise stated, when I provide my understanding and
`
`analysis below, it is consistent with the level of a POSITA prior to this priority
`
`date.
`
`VI. BACKGROUND FOR THE ’880 PATENT
`
`A.
`
`Flat Panel Displays
`
`44. Flat panel displays, defined as a display with a thinner depth than height
`
`or width, have been around for more than 50 years; they are now ubiquitous
`
`in products ranging from TVs to cell phones to computers to watches, and
`
`13
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 16
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`many other applications. I have been part of the industry for 49 years and have
`
`participated in the development of flat panel display technologies and their
`
`introduction into products.
`
`45. The first commercially available flat panel displays were called plasma
`
`displays and were developed in the 1960's; the first large screen flat TVs were
`
`color plasma displays. In parallel, liquid crystal display (“LCD”) technology
`
`was under development starting in the late ’60s and early 70’s. Early LCDs
`
`were very simple displays, e.g., 7-segment displays for watches and clocks;
`
`individual pixels were driven directly or were multiplexed. The next stage of
`
`development for LCDs was the development of larger, more complex displays
`
`with 100 or more rows; these were generally called “passive matrix” LCDs
`
`because they were driven without any transistors or diodes at each pixel. The
`
`performance of these displays was sufficient to enable displays with resolu-
`
`tions up to 640x480, which was suitable for portable computing devices.
`
`However, the performance (e.g., contrast ratio, viewing angle, and response
`
`time) was barely sufficient to meet customer needs. It should be noted that the
`
`term “passive display” is also used in the industry to refer to a display that
`
`does not generate light (in contrast to a plasma display or OLED display), but
`
`instead modulates light; therefore, a source of light is required, usually behind
`
`the LCD, to create an image.
`
`14
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 17
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`46. As already mentioned, plasma displays were commercially developed
`
`for computer screens as well as television displays; actually, the first flat panel
`
`displays for computers were monochrome i.e., one-color plasma displays.
`
`While these displays were thinner than the cathode ray tubes (“CRTs”) in com-
`
`puter monitors and TVs, they were still relatively heavy and were inefficient
`
`compared to other flat panel technologies.
`
`47.
`
`It was the development of the thin film transistor (“TFT”) in the 70’s
`
`and 80’s that ushered in the era of color flat panel displays for small TVs
`
`(1980’s) and notebook computers (early 1990’s), and eventually many other
`
`products that we use today.
`
`B. Active matrix TFT arrays
`
`48. Active matrix arrays comprise thin film transistors; for reference, a
`
`transistor is a solid-state electronic device that is used to control the flow of
`
`electricity in electronic equipment and usually consists of a small block of a
`
`semiconductor with at least three electrodes. Further, a “source” is defined as
`
`an electrode in a field-effect transistor that supplies the charge carriers for
`
`current flow and “drain” is defined as an electrode in a field-effect transistor
`
`toward which charge carriers move.
`
`49. The thin film transistor is a field effect transistor that is fabricated by
`
`depositing layers on a substrate such as glass or plastic to make the transistors;
`
`15
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 18
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`the layers generally include a semiconductor layer, insulating layers, and elec-
`
`trodes made of metals or low-resistance semiconductors. Current flows in the
`
`transistor between a source electrode and drain electrode and is controlled by
`
`a voltage on a gate electrode. Typical semiconductor layers for thin film tran-
`
`sistors are amorphous silicon (“aSi”) or polycrystalline silicon (“pSi”), but
`
`other materials such as CdSe and zinc oxide compounds have been or are in
`
`use today. Unlike commercial integrated circuits that use high temperature
`
`processing on silicon wafers, the TFT processes must be performed at temper-
`
`atures compatible with glass or plastic substrates.
`
`C. Active-matrix Organic Light-Emitting Diode ("OLED") Dis-
`plays
`
`1. OLED light emission
`
`50. OLED materials were first observed in the 1950's, but the first OLED
`
`devices useful for displays was published by Chin Wan Tang et al. in 1987. A
`
`typical OLED is composed of a layers of organic materials between an anode
`
`and cathode; when a positive voltage is applied to the anode, electrons and
`
`holes will flow into the emitting layer and light will be emitted through charge
`
`recombination of exited states. Over the years, materials with different
`
`bandgaps have been developed such that red, green, and blue OLEDs are now
`
`available.
`
`16
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 19
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`51. A consideration in the design of OLED color displays is the relative
`
`efficiency of each emitting layer; that is, the efficiency of red, green, and blue
`
`organic emitting layers can be different. This means different currents are re-
`
`quired to achieve the correct brightness to make white light (red + green +
`
`blue). One solution is to use different drive current settings for each color, but
`
`this can complicate the pixel circuitry. Another solution commonly adopted is
`
`to vary the size of the individual subpixels; for example, if blue has lower
`
`efficiency, then the blue area is increased.
`
`2. OLED circuit considerations
`
`52. Unlike the active-matrix LCD, light is created in the OLED when cur-
`
`rent flows; the higher the current, the greater the light output. OLED displays
`
`can be fabricated without an active matrix, but the resolution and complexity
`
`are limited; almost all OLED displays used today in cell phones, tablets, per-
`
`sonal computers, and TVs are active-matrix OLED (“AMOLED”) displays.
`
`53. Because of the need to handle higher current levels than LCDs, either
`
`pSi or other high-mobility semiconductor TFTs are used. The basic drive cir-
`
`cuit for an OLED pixel is shown below on the right, compared to the LCD
`
`drive circuit on the left. At a minimum, two TFTs and a storage capacitor are
`
`used (switching TFT and driving TFT); current to the OLED is controlled by
`
`the voltage on the storage capacitor and supplied by an external power supply
`
`17
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 20
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`VDD. To address and drive the active-matrix OLED display, Vselect is ap-
`
`plied to each row of the display sequentially. When a switching TFT is turned
`
`on, a current will flow to charge the storage capacitor to Vdata. Once the volt-
`
`age is set, the switching TFT is turned off and current will flow to the OLED
`
`through the driving transistor based on the stored value of Vdata until the next
`
`refresh period (after all the other rows of the display are addressed).
`
`
`
`54. Unfortunately, if the driving TFT is not stable or has any change in
`
`threshold voltage or I-V characteristics, the drive current will not produce the
`
`desired output brightness. To solve this problem, various alternate TFT de-
`
`signs have been developed that allow for "sensing" of the Vth and/or I-V char-
`
`acteristics (as well as OLED degradation); all these solutions use more than
`
`two TFTs and some use additional capacitors. In addition, with these more
`
`complex circuits, write current can flow through the drive transistor during
`
`the writing period to sense its characteristics, e.g., threshold voltage.
`
`18
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 21
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`55. The inventions disclosed in the ’880 patent are examples of active-ma-
`
`trix circuits that add additional TFTs to solve issues related to voltage drop,
`
`threshold voltage shift, threshold voltage variations in drive transistors, and
`
`motion-related artifacts. In particular, the ’880 patent discloses a circuit with
`
`four transistors and one capacitor (“4T-1C”); the fourth transistor is used to
`
`reset the gate of the driving transistor and the storage capacitor before writing
`
`new data.
`
`VII. OVERVIEW OF THE ’880 PATENT
`
`A. Background of the '880 Patent
`
`56. The ’880 patent, titled “Display Apparatus and Drive Control Method
`
`Thereof,” was filed by Tsuyoshi Ozaki and Jun Ogura on May 23, 2006, and
`
`was issued on Jan. 11, 2011. It claims a priority date of May 24, 2005.
`
`57. Casio, the original assignee of the ’880 patent was a pioneer in the de-
`
`velopment of practical and high performing displays utilizing organic light
`
`emitting diodes (OLEDs). The ’880 patent taught innovative designs for “ac-
`
`tive matrix” OLED displays and methods to control the driving of the pixels
`
`in the display (See Ex. 1001, ’880 patent at Abstract.)
`
`58. The ’880 patent explains that addressing of prior art active-matrix
`
`OLED displays consisted of a write time period and a display time period.
`
`While the performance for still images could be adequate, a problem exists
`
`19
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`SAMSUNG V. SOLAS
`IPR2021-00591
`Exhibit 2001
`Page 22
`
`
`
`Case No. IPR2021-00591
`U.S. Patent No. 7,868,880
`for moving images because “image information displayed in the previous
`
`frame period can become visually recognized more easily as an afterimage.”
`
`Consequently, “blurs and stains of the image information occur” which leads
`
`to deterioration of the display image quality. Ex. 1001, ’880 patent at 2:41-51.
`
`To resolve this issue, a display drive method (referred to as “pseudo-impulse
`
`type display drive method”) could be realized to improve the quality of mov-
`
`ing images. However, an additional writing period of the blanking data and
`
`black display period have to be added within each frame; this results in the
`
`need for writing the image data at a higher speed such that “writing insuffi-
`
`ciency occurs owing to the insufficiency of the time
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