IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`
`In re U.S. Patent No. 8,685,543
`
`Filed:
`
`May 31, 2012
`
`Issued:
`
`Apr. 1, 2014
`
`Inventors: Toshihiro Iwakuma, Chishio Hosokawa, Hidetsugu Ikeda, Seiji
`
`Arakane, and Takashi Arakane
`
`Assignee:
`
`Idemitsu Kosan Co., Ltd.
`
`Title:
`
`Material for Organic Electroluminescent Devices and Organic
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`Electroluminescent Devices Made by Using Same
`
`
`Mail Stop PATENT BOARD, PTAB
`Patent Trial and Appeal Board
`U.S.P.T.O.
`P.O. Box 1450
`Alexandria, VA 22313-1450
`
`DECLARATION OF BENJAMIN J. SCHWARTZ
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`I, Benjamin J. Schwartz, make this declaration in connection with the
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`petition for inter partes review submitted by Petitioner for U.S. Patent No.
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`8,685,543 (“the ’543 patent”). All statements herein made of my own knowledge
`
`are true, and all statements herein made based on information and belief are
`
`
`
`RHEMK-1003.001
`
`
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`
`
`
`In re U.S. Patent No. 8,685,543
`
`Filed:
`
`May 31, 2012
`
`Issued:
`
`Apr. 1, 2014
`
`Inventors: Toshihiro Iwakuma, Chishio Hosokawa, Hidetsugu Ikeda, Seiji
`
`Arakane, and Takashi Arakane
`
`Assignee:
`
`Idemitsu Kosan Co., Ltd.
`
`Title:
`
`Material for Organic Electroluminescent Devices and Organic
`
`Electroluminescent Devices Made by Using Same
`
`
`Mail Stop PATENT BOARD, PTAB
`Patent Trial and Appeal Board
`U.S.P.T.O.
`P.O. Box 1450
`Alexandria, VA 22313-1450
`
`DECLARATION OF BENJAMIN J. SCHWARTZ
`
`I, Benjamin J. Schwartz, make this declaration in connection with the
`
`petition for inter partes review submitted by Petitioner for U.S. Patent No.
`
`8,685,543 (“the ’543 patent”). All statements herein made of my own knowledge
`
`are true, and all statements herein made based on information and belief are
`
`
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`RHEMK-1003.001
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`
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`believed to be true. I am over age 21 and otherwise competent to make this
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`declaration. Although I am being compensated for my time in preparing this
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`declaration, the positions articulated herein are my own, and I have no stake in the
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`outcome of this proceeding or any related litigation or administrative proceedings.
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`I.
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`BACKGROUND AND QUALIFICATIONS
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`1.
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`Exhibit RHEMK-1004 is my curriculum vitae. As shown in my
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`curriculum vitae, I have devoted my career to the field of chemistry, including
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`research pertaining to quantum theory, light emission in LEDs, and electron
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`transfer. I earned my Bachelor of Science degree in both Physics and Chemistry
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`from the University of Michigan in May 1986. Thereafter, I earned my Ph.D. in
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`Physical Chemistry from the University of California, Berkeley in December 1992.
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`I am currently a Professor in the Department of Chemistry and Biochemistry at
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`UCLA. My current research includes (1) femtosecond laser studies of the
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`dynamics of charge-transfer reactions and solvated electrons and (2) classical and
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`quantum non-adiabatic computer simulations of charge transfer, solvation
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`dynamics and the nature of linear response, including the development of multi-
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`electron quantum simulation algorithms, and (3) studies of the spectroscopy,
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`device physics and efficiency of organic solar cells, including photovoltaic devices
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`based on conjugated polymers and fullerenes.
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`2
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`RHEMK-1003.002
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`2.
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`In connection with my work, I have extensive experience in the
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`research, theory, and application of light emitting materials, including organic
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`electroluminescence devices. I spent nearly a decade, first as a postdoctoral
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`student and later as an independent researcher at UCLA studying organic materials
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`and their properties when used in light-emitting diodes, and as a result I am also a
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`named inventor on several issued and pending U.S. patents that pertain to light-
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`emitting organic materials. In the mid-2000’s, I began focusing my research
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`activities on organic photovoltaics (OPVs) and OPVs remain a subject of my
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`current research interests.
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`3.
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`I have been retained in this matter by Weil, Gotshal & Manges LLP
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`(“Weil”) to provide various observations regarding the ’543 patent. I am being
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`compensated at the rate of $300 per hour for my work. My fee is not contingent on
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`the outcome of this matter or on any of the positions I have taken, as discussed
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`below.
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`4.
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`I have been advised that Weil represents the Petitioner in this matter. I
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`have no direct financial interest in the Petitioner.
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`5.
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`I have been advised that Idemitsu Kosan Co., Ltd. (hereinafter
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`referred to as “Idemitsu”) owns the ’543 patent. I have no financial interest in
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`Idemitsu or the ’543 patent. I have not ever had any contact with Idemitsu or the
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`3
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`RHEMK-1003.003
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`
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`inventors of the ’543 patent, Toshihiro Iwakuma, Chishio Hosokawa, Hidetsugu
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`Ikeda, Seiji Arakane, and Takashi Arakane.
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`II. MATERIALS CONSIDERED
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`6.
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`In preparing this declaration, I have reviewed the following:
`
`a.
`
`b.
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`The ’543 patent (Exhibit 1001 to the petition);
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`Excerpts from the prosecution history of the ’543 patent
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`(Exhibit 1002 to the petition);
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`c.
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`JP Patent Application 2000-053956 to Onikubo Shunichi et al.
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`(“JP-956”; Exhibit 1005 to the petition);
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`d.
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`U.S. Patent App. 2002/0028329 to Ise et al. (“Ise 329”; Exhibit
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`1006 to the petition);
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`e.
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`J. Herbich, Phosphoresecent intramolecular charge transfer
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`triplet states, Chem. Phys. Lett. 262
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`(1996) 633-642
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`(“Herbich”; Exhibit 1007 to the petition);
`
`f.
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`Translation of Tribunal Opinion from Korean Invalidation
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`Proceeding for the Korean counterpart of the ’543 Patent (“KR
`
`Opinion”; Exhibit 1008 to the petition);
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`g.
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`S. Bonesi and Rossa Erra-Balsells, Electronic spectroscopy of
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`carbazole and N- and C-substituted carbazoles in homogeneous
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`4
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`RHEMK-1003.004
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`
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`media and in solid matrix, Journal of Luminescence 93 (2001)
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`51–74 (“Bonesi”; Exh. 1009 to the petition);
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`h.
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`K.R.
`
`Justin Thomas et al., Light-Emitting Carbazole
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`Derivatives: Potential Electroluminescent Materials, J. Am.
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`Chem. Soc. 123 (2001) 9404-9411 (“Thomas”; Exh. 1010 to
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`the petition);
`
`i.
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`Baldo et al., Phosphorescent materials for application to
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`organic light emitting devices, Pure Appl. Chem. 71 (1999)
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`2095-2106 (“Baldo”; Exh. 1011 to the petition).
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`III. THE PERSON OF ORDINARY SKILL IN THE RELEVANT FIELD
`IN THE RELEVANT TIMEFRAME
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`7.
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`I have been informed that “a person of ordinary skill in the relevant
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`field” is a hypothetical person to whom an expert in the relevant field could assign
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`a routine task with reasonable confidence that the task would be successfully
`
`carried out. I have been informed that the level of skill in the art is evidenced by
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`the prior art references. The prior art discussed herein demonstrates that a person
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`of ordinary skill in the art, at the time the ’543 patent was filed, was aware of
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`various aspects luminescent materials and the use of such materials in conjunction
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`with, at least, anodes, cathodes, host materials, doping materials, hole injecting
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`materials, and electron injecting materials. Such a person would have a bachelor’s
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`degree in chemistry, physics, materials science or a related discipline and two to
`5
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`RHEMK-1003.005
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`three years of relevant experience, which could be obtained either through graduate
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`studies or work experience. Such a person would have had an understanding of
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`the electronic structure of organic materials and how the electronic structure of
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`such materials impacts their spectroscopic properties and performance in organic
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`electroluminescent devices.
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`8.
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`Based on my experience, I have a good understanding of the
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`capabilities of a person of ordinary skill in the relevant field. I have interviewed,
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`trained, supervised, directed and advised many such persons over the course of my
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`career in addition to being a person of at least ordinary skill in the art working in
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`the field at the time of the application for the ’543 patent.
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`IV. RELEVANT LEGAL STANDARDS
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`9.
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`I have been asked to provide my opinions regarding whether the
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`claims of the ’543 patent are anticipated or rendered obvious by the prior art.
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`10.
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`It is my understanding that in order for prior art to anticipate a claim
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`under 35 U.S.C. § 102, the reference must disclose every element of the claim.
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`11.
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`It is my understanding that a claimed invention is unpatentable under
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`35 U.S.C. § 103 if the differences between the invention and the prior art are such
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`that the subject matter as a whole would have been obvious at the time the
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`invention was made to a person having ordinary skill in the art of the claimed
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`invention. I also understand that the obviousness analysis takes into account factual
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`6
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`RHEMK-1003.006
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`
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`inquiries including the level of ordinary skill in the art, the scope and content of the
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`prior art, the differences between the prior art and the claimed subject matter, and
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`any secondary considerations which may suggest the claimed invention was not
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`obvious.
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`12.
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`I have been informed that the Supreme Court has recognized several
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`rationales for combining references or modifying a reference to show obviousness
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`of claimed subject matter. I understand some of these rationales include the
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`following:
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`a.
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`combining prior art elements according to known methods to
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`yield predictable results;
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`b.
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`simple substitution of one known element for another to obtain
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`predictable results;
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`c.
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`use of a known technique to improve a similar device (method,
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`or product) in the same way;
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`d.
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`applying a known technique to a known device (method, or
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`product) ready for improvement to yield predictable results;
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`e.
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`choosing from a finite number of identified, predictable
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`solutions, with a reasonable expectation of success; and
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`7
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`RHEMK-1003.007
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`f.
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`showing that the claimed product was not one of innovation but
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`of ordinary skill and commonsense, such that the claimed
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`invention was obvious to try;
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`g.
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`some teaching, suggestion, or motivation in the prior art that
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`would have led one of ordinary skill to modify the prior art
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`reference or to combine prior art reference teachings to arrive at
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`the claimed invention.
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`V. BACKGROUND OF THE ART
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`13. Organic materials for use in electroluminescent devices, such as
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`electroluminescent displays (“ELDs”) or organic light emitting diodes (“OLEDs”),
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`have been researched and known since at least the 1980s. In the time since their
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`discovery as commercially viable options for electroluminescent devices, much
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`research has been done to achieve thin film layer materials that allow for the mass
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`production of OLED products in high volumes with great luminous efficiency and
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`great functional longevity across the necessary colors.
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`14. The mechanism of operation of OLEDs is well understood. An
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`OLED consists of one or more organic layers sandwiched between an anode and a
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`cathode. The organic layers may consist of one or more of an emitting layer, an
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`electron transporting layer, an electron injecting layer, a hole transporting layer,
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`and a hole injecting layer. The cathode injects electrons into the organic layers,
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`8
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`RHEMK-1003.008
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`while the anode injects holes into the organic layers. When the device is operated,
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`the electrons and holes migrate towards one another due to the presence of the
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`applied electric field and recombine in the emitting layer, leading either to the
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`direct emission of light, or to an excited state that can undergo energy transfer to
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`another compound that ultimately functions as the light emitter.
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`15. The electrons and holes injected into an OLED have spin, a quantum
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`mechanical quantity associated with fundamental particles. When an electron and
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`hole recombine, the individual spins can combine in one of 4 different ways. One
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`of these ways is an antisymmetric combination, which allows the net spin to cancel
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`out; this is referred to as a spin singlet or simply a singlet state. The ground states
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`of most molecules are singlet. Excited singlet states are often highly fluorescent,
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`and the fluorescent emission from these states can be used as part of an OLED.
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`16. The other three ways the spins can combine are symmetric, which
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`allows the spins to add; these three ways are equivalent in the absence of a strong
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`magnetic field, and thus are referred to as spin triplets, or simply triplet states. The
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`lowest triplet state in an organic molecule almost always lies several tenths of an
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`eV below the lowest excited singlet state in energy. Many molecules are able to
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`emit light from the lowest triplet state; this light is referred to as phosphorescence.
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`The use of phosphorescence is desirable because when the electrons and holes
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`recombine, three times as many triplets are generated as singlets, so using
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`9
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`RHEMK-1003.009
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`phosphorescent emission could improve the efficiency of the device by up to a
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`factor of 3. This concept was well-known long before the filing of the ’543 patent,
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`and was discussed in numerous prior art references, including the Baldo reference
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`that I discuss in detail in paragraphs 32-35 and 119-121.
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`17. Another advantage of using triplet states is that they have a much
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`longer lifetime than singlet states: a typical singlet states lives only a few ns,
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`whereas triplet states can live from µs to many seconds. This long lifetime gives
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`ample opportunity for the triplet state to undergo an energy transfer process to
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`another molecule (usually one containing a heavy metal such as Pt or Ir), which
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`can then itself phosphoresce, or which can absorb the triplet energy to reach an
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`excited singlet state
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`then fluoresce.
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` Thus, a strategy for building an
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`electroluminescent display is to choose an organic host molecule that has its lowest
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`excited singlet state located so that the fluorescence would be in the near UV or
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`violet region of the spectrum. This causes the molecule’s triplet state (and thus its
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`phosphorescence) to lie in the blue region of the spectrum. The emission from the
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`triplet state could then be used directly as the blue element of a display, or
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`molecules with lower energy gaps can be doped to into the host material to absorb
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`the triplet energy to create either blue, green, or red emissive elements for a
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`display. This strategy was well-known long before the filing of the ’543 patent,
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`10
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`RHEMK-1003.010
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`and was documented in numerous prior art references, including the Baldo and Ise
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`329 references that I discuss in detail in paragraphs 21-24, 32-35, and 118-124.
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`18. Multiple layers can be used to further improve the device efficiency.
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`The use of layers to specifically transport electrons away from the cathode or holes
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`away from the anode can help by improving charge injection and/or by allowing
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`the recombination to occur in a location far from the electrode (proximity to the
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`electrode can cause quenching of excited states and thus loss of luminescence).
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`These electron and hole transporting layers can be either different materials from
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`those used for emission, or could be the same, depending the specific details of the
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`device architecture. The use of multiple layers to improve the efficiency of
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`organic electroluminescent devices is another concept that was well-known prior to
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`the filing of the ’543 patent, and was disclosed in numerous prior art references,
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`including the Ise 329, JP-956, and Baldo references that I discuss in detail in
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`paragraphs 19-24 and 32-35.
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`VI. THE SCOPE AND CONTENT OF THE CITED ART
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`A.
`
`19.
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`JP-956
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`JP-956 is a Japanese patent application published on February 22,
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`2000 entitled “Luminescent Material for Organic Electroluminescent Element and
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`Organic Electroluminescence Element Using the Same.” JP-956 is directed to the
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`preparation of organic electroluminescent devices that purportedly offer not just
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`11
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`RHEMK-1003.011
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`high luminance, but also stability over repeated use. RHEMK-1005 at [0005]. To
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`this end, JP-956 discloses luminescent materials of “General formula [1]”:
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`RHEMK-1005 at [0007]
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`20.
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`JP-956 discloses 25 exemplary compounds in the “General formula
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`[1]” category, including example (5) in which two carbazolyl groups are bound to
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`a central quinoxaline group:
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`
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`RHEMK-1005 at [0020]
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`JP-956 specifies that the “compound indicated by general formula [1] in this
`
`invention has excellent electroluminescent property because it is a compound that
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`exhibits strong fluorescence in the solid state, for which reason it can be used
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`within the luminescent layer as a luminescent material.” RHEMK-1005 at [0026].
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`JP-956 further summarizes the general structure of the organic electroluminescent
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`device, including the anode, cathode, and the various components of the luminous
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`layer. See RHEMK-1005 at [0002], [0009], [0026].
`12
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`RHEMK-1003.012
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`B.
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`21.
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`Ise 329
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`Ise 329 is a U.S. patent application published on March 7, 2002. It is
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`directed to a light-emitting element including a host material with a minimum
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`triplet energy gap (i.e., the gap in energy between the ground state and the lowest
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`lying triplet state). Ise 329 documents why it is desirable to have a high triplet
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`energy gap in the host material of the light-emitting element. Briefly, as discussed
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`above, a high triplet energy gap in the host material makes it possible to transmit
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`energy to a dopant emitter material that can emit blue light with high efficiency:
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`In the above light-emitting element, the above light-emitting layer is
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`composed of a light-emitting material (guest material) and a host
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`material having a high minimum excitation triplet energy level (T1)
`higher than the T1 of the light emitting material. This makes it
`possible to transfer the energy of the above triplet exciton to the T1
`level of the light emitting material efficiently, with the result that
`blue light can be emitted with high luminance efficiency.1
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`RHEMK-1006 at [0010]; see also RHEMK-1006 at [0008] (“it is an object of the
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`present invention to provide a light-emitting element which can emit light in the
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`blue region with high luminance efficiency . . . .”).
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`22. As possible host materials, Ise 329 discloses compounds in which
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`aromatic hydrocarbons or hetero rings are bound to a central coupling group.
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`
`
` 1
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` Emphasis supplied throughout, unless otherwise noted.
`13
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`RHEMK-1003.013
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`RHEMK-1006 at [0014], [0046], [0047]. The general formulae for such
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`compounds disclosed in Ise 329 is as follows:
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`The host material is preferably a compound represented by the
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`following general formula (I):
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`General formula (I)
`
`
`
`
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`L1-(Q1)n1
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`wherein L1 represents a bivalent or more coupling group; Q1
`represents an aromatic hydrocarbon ring or an aromatic hetero ring;
`and n1 represents a number of 2 or more, plural Q1 may be the same
`or may be different from each other.
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`RHEMK-1006 at [0012]-[0014].
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` This general formula encompasses
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`the
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`compounds of formula (Cz-)nMm that are claimed in the ’543 patent and which are
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`discussed in detail below.
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`23. Notably, Ise discloses that “examples of the host material are
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`materials having a carbazole skeleton . . . .” RHEMK-1006 at [0150]. Ise 329
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`discloses as two such example compounds with carbazolyl groups bound to
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`nitrogen containing heterocycles:
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`14
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`RHEMK-1003.014
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`
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`RHEMK-1006 at [0119]
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`24.
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`Ise 329 further discloses the structure of organic electroluminescent
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`devices based on the use of such materials, including the arrangement of the
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`emitting material between the anode and cathode and the use of additional layers
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`(e.g., hole injecting layer, hole transmitting layer, electron injecting layer, electron
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`transmitting layer) that can be used to improve performance. See RHEMK-1006 at
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`[0024].
`
`C. Herbich
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`25. Herbich is a 1996 publication in Chemical Physics Letters describing
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`spectroscopic studies of derivatives of 3,6-di-tert-butylcarbazole that include
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`various aromatics. The studied compounds are depicted below and include two
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`compounds (CNP and CNO) in which a carbazolyl is bound to a nitrogenous
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`heterocycle that acts as an “electron acceptor”:
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`15
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`RHEMK-1003.015
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`RHEMK-1007 at 634.
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`
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`26. Herbich reports both the fluorescence and phosphorescence spectra
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`for these compounds. The phosphorescence spectra of these compounds shows
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`peaks in the 22,500 to 25,000 wavenumber region, which those of skill in the art
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`would understand correspond to a relatively high triplet energy gap of 2.8 to 3.1
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`eV.
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` This
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`renders
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`the compounds useful
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`for blue-emitting organic
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`electroluminescent devices, for the reasons set forth in Ise 329 and as explained
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`above in paragraphs 14-17.
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`27. Herbich further concludes that “investigations of the lowest excited
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`triplet state T1 in the series of D-A carbazole derivatives undoubtedly show a
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`change in their electronic structure with increasing electron affinity of the acceptor
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`moiety.” RHEK-1007 at 641. That is, Herbich explains that one can tune the
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`electronic structure (and hence the singlet and triplet energy gaps) of carbazolyl
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`derivatives by adjusting the extent to which the heterocyclic acceptor group is
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`electron withdrawing. One of skill in the art engaged in the process of designing
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`16
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`RHEMK-1003.016
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`organic electroluminescent devices would have thus found the teachings of
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`Herbich useful.
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`D. Bonesi
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`28. Bonesi is a spectroscopic study of 21 different carbazole derivatives,
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`focusing on the properties of the first excited singlet and triplet states of these
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`compounds. Table 2 of Bonesi summarizes parameters spectroscopic properties
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`for numerous of the studied compounds, including their singlet and triplet energy
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`gaps. The singlet and triplet energy gaps are shown below in the columns labeled
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`E(S1-S0) and E(T1-S0), respectively:
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`RHEMK-1009 at 57, Table 2. The 11 reported singlet gaps fall within a relatively
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`narrow range of 3.32-3.94 eV, while the 17 reported triplet gaps are a generally a
`17
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`
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`RHEMK-1003.017
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`few tenths of an eV lower and fall within a relatively narrow range of 2.61-3.04
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`eV. From Bonesi, one of ordinary skill in the art would understand that the singlet
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`and triplet gaps of carbazole derivatives generally fall within a relatively narrow
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`range, and that the introduction of different substituents can influence the gap by
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`an amount on the order of several tenths of an eV.
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`E.
`
`Thomas
`
`29. Thomas
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`is a 2001 article entitled “Light-Emitting Carbazole
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`Derivatives: Potential Electroluminescent Materials.” Thomas describes the
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`preparation of a series of carbazole compounds, and characterizes their properties
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`as potential emitters in organic light emitting devices.
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`30. Thomas summarizes
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`the well-known advantages of carbazole
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`derivatives for use in light emitting devices, including stability and easy
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`functionalization:
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`It is well recognized that the thermal stability or glassy-state
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`durability of organic compounds can be greatly improved upon
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`incorporation of a carbazole moiety
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`in
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`the core structure.
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`Furthermore, the carbazole moiety can be easily functionalized at its
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`3-, 6-, or 9-positions and covalently linked to other molecular
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`moieties.
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`RHEMK-1010 at 9404.
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`18
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`RHEMK-1003.018
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`31. Thomas goes on to explain how the color of the luminescence can be
`
`tuned through functionalization of the carbazole moiety:
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`Another interesting feature of these carbazole compounds is that the
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`luminescence wavelength can be tuned from green to blue through
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`appropriate modifications of the structure, such as the change of the
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`substituents at the peripheral nitrogen atom or the spacer between the
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`peripheral nitrogen atom and the 3,6-carbon atoms of the central
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`carbazole.
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`RHEMK-1010 at 9411; see also RHEMK-1010 at Abstract (“The emission
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`wavelength ranges from green to blue and is dependent on the substituent at the
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`peripheral nitrogen atoms.”).
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`F.
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`Baldo
`
`32. Baldo is a 1999 review article that summarizes well known properties
`
`of different categories of organic phosphors, including organic phosphors used for
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`organic light-emitting devices. Baldo summarizes the obstacles to efficient
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`luminescence in such devices.
`
`33. Briefly, Baldo explains that luminescence arises from “relaxation of
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`an excited state to the ground state.” RHEMK-1011 at 2095. Baldo further
`
`explains that excited triplet states (i.e., “spin-symmetric” states) are three times as
`
`likely to be produced in a device based on electrical injection as excited singlet
`
`states (i.e., “spin antisymmetric” states):
`
`19
`
`RHEMK-1003.019
`
`
`
`[T]he combination of an electron and a hole with uncorrelated spins
`
`is three times as likely to result in a spin-symmetric as opposed to a
`
`spin antisymmetric state [6]. From the multiplicity of the exciton
`
`spin states, S=1 excitons are known as triplets, and S=0 excitons are
`
`singlets.
`
`RHEMK-1011 at 2095. Thus, Baldo explains that “if the energy contained in the
`
`triplet excitons cannot be directed to luminescence, the efficiency of an OLED is
`
`reduced by 75%.” RHEMK-1011 at 2095. The barrier to redirecting the energy of
`
`the triplet states, Baldo explains, is that triplet to singlet transitions are forbidden
`
`by conservation of angular momentum. See RHEMK-1011 at 2095 (“As the
`
`ground state is generally spin antisymmetric with a total spin of S=0, the decay of
`
`S=0 excitons is allowed. In contrast, the decay of S=1 excitons is not allowed.”);
`
`RHEMK-1011 at 2095 (“Phosphorescence is distinguished from fluorescence by
`
`the speed of the electronic transition that generates luminescence. Both processes
`
`require
`
`the relaxation of an excited state
`
`to
`
`the ground state, but
`
`in
`
`phosphorescence the transition is ‘forbidden’ and as a consequence it is slower
`
`than fluorescence, which arises from allowed transitions.”).
`
`34. Baldo then goes on to document that the known solution to this
`
`problem is to introduce dopants that can couple (or “mix”) S=0 and S=1 excitons
`
`into the host material:
`
`20
`
`RHEMK-1003.020
`
`
`
`Fortunately, although the decay of a triplet state is disallowed by the
`
`conservation of spin symmetry, it is occasionally observed if the
`
`triplet state is perturbed such that the transition becomes weakly
`
`allowed. In this case, the decay of the triplet state may still be very
`
`slow,
`
`but
`
`phosphorescence
`
`is
`
`generated. But
`
`efficient
`
`phosphorescence is rare at room temperature, and attempting to find
`
`a material that also readily transports charge is a challenging task.
`
`Moreover, very few materials luminesce efficiently in homogenous
`
`films due to the quenching of emission by surrounding molecules.
`
`The solution to these demands on OLED materials is found by
`doping the luminescent material into a charge transport host
`material [7]. Emission then occurs in one of two ways: either by
`
`direct carrier trapping and exciton formation on the luminescent dye,
`
`or by exciton formation in the host and energy transfer to the
`
`luminescent guest.
`
`RHEMK-1011 at 2095-96.
`
`35. Baldo goes on to discuss a variety of different options for
`
`combinations of dopants and host materials that allow one to redirect triplet
`
`excitations to efficient luminescence. One such option discussed is to use the bis
`
`carbazole derivative CBP as the host material:
`
`
`
`21
`
`RHEMK-1003.021
`
`
`
`RHEMK-1011 at 2101, Fig. 5b.
`
`An exemplary dopant disclosed for use with CPB is the platinum compound
`
`PtOEP. See RHEMK-1011 at 2101, Fig. 5a. As Baldo explains, such heavy metal
`
`compounds enhance “spin-orbit coupling,” which “mixes singlet and triplet excited
`
`states” and hence allows one to redirect triplet excitations from carbazole
`
`derivatives in particular to luminescence from the dopant. RHEMK-1011 at 2098.
`
`VII. U.S. PATENT NO. 8,685,543
`
`36. The ’543 patent, like Ise 329, is directed to organic electroluminescent
`
`devices. Specifically, the ’543 patent states that it has as an objective of
`
`“providing a material for organic EL devices which emits bluish light with high
`
`purity of light . . . .” RHEMK-1001 at 1:67-2:2; see also RHEMK-1001 at 48:16-
`
`21 (“As described above in detail, by utilizing the material for organic
`
`electroluminescence devices comprising the compound represented by general
`
`formula (1) of the present invention, the organic electroluminescence device
`
`emitting blue light having an excellent purity of color at a high efficiency of light
`
`emission can be obtained.”). In this regard, the ’543 patent has the same primary
`
`objective as Ise 329.
`
`37. To meet this objective, the ’543 patent discloses using compounds of
`
`“formula (1)” “in which a heterocyclic group having nitrogen was bonded to a
`
`carbazolyl group as the host material” in an organic electroluminescent device.
`
`22
`
`RHEMK-1003.022
`
`
`
`RHEMK-1001 at 2:6-8. These are the same types of compounds disclosed in JP-
`
`956, Herbich, and Ise-329, for example. The ’543 patent, like Ise 329, explains
`
`that these compounds have high energy gaps and are thus useful for the creation of
`
`efficient blue emitters in organic electroluminescent devices:
`
`The organic EL device of the present invention emits bluish light,
`
`and the purity of color of the emitted light is as excellent as (0.12,
`0.11) to (0.16, 0.19). This property is exhibited since the material
`
`for organic EL devices comprising the compound represented by
`general formula (1) of the present invention has a great energy
`gap.
`
`* * *
`
`The compound represented by general formula (1) in the present
`
`invention
`is useful also as
`the organic host material for
`phosphorescence devices since the singlet energy gap is as high as
`
`2.8 to 3.8 eV and the triplet energy gap is as high as 2.5 to 3.3 eV.
`
`RHEMK-1001 at 22:53-58, 23:1-5; see also RHEMK-1001 at 45:35-38 (“Since the
`
`energy gap of the compounds of the present invention was great, the light emitting
`
`molecules having great energy gaps could be mixed into the light emitting layer
`
`and used for the light emission.”).
`
`38. The high energy gaps in the ’543 patent are used in the same way as
`
`in Baldo and Ise 329. Specifically, the ’543 patent states that the high energy gap
`
`23
`
`RHEMK-1003.023
`
`
`
`allows for efficient transfer of triplet energy to heavy metal-based dopants and that
`
`subsequently efficiently emits light within the luminescent layer:
`
`By using a multi-layer structure for the organic EL device, decreases
`
`in the luminance and the life due to quenching can be prevented, and
`
`the luminance of emitted light and the efficiency of light emission
`can be improved with other doping materials. By using other
`doping materials contributing to the light emission of the
`phosphorescence in combination, the luminance of emitted light
`and the efficiency of light emission can be improved in
`comparison with those of conventional devices.
`
`RHEMK-1001 at 24:1221. In particular, the ’543 patent explains that the gaps in
`
`the disclosed carbazole derivatives are higher than the gaps in organometallic
`
`complexes used as dopants:
`
`It is also considered that, when the compound of the present
`
`invention is used for the light emitting layer of the phosphorescence
`device, an excited triplet level in an energy state higher than the
`
`excited triplet level of a phosphorescent organometallic complex
`
`comprising a metal selected from the Group 7 to 11 of the Periodic
`
`Table contained in the layer, is achieved . . . .
`
`RHEMK-1001 at 23:33-39; see also RHEMK-1001 at 24:60-65 (“As the light
`
`emitting material, phosphorescent organometallic complexes are preferable
`
`since the external quantum efficiency of the device can be improved.
`
`Examples of the metal in the phosphorescent organometallic complex include
`
`24
`
`RHEMK-1003.024
`
`
`
`ruthenium, rhodium, palladium, silver, rhenium, osmium, iridium, platinum and
`
`gold.”); RHEMK-1001 at 42: 7-9 (“At the same time tris(2-phenylpyridine)iridium
`
`(Ir(ppy)3 shown in the following) as the phosphorescent Ir metal complex
`
`dopant was added.”).
`
`39. Thus, the ’543 patent discloses organic electroluminescent devices
`
`based on compounds that were well known in the prior art and that operate
`
`according to the exact same mechanisms that were known in the prior art,
`
`including the doping mechanisms and techniques disclosed in Baldo and Ise 329
`
`that are discussed below in paragraphs 117-124.
`
`40. The ’543 patent includes 22 claims, which may be summarized as
`
`follows:
`
`• Claims 1-2 are directed to a compound of formula (Cz-)nMm,
`where Cz is a substituted or unsubstituted carbazolyl group and M
`
`may be a number of substituted or unsubstituted heteroaromatic
`
`groups. See RHEMK-1001 at 2:10-23.
`
`• Claims 3-6 and 12-17 are directed to organic electroluminescent
`devices that utilize a compound of formula (Cz-)nMm.
`
`• Claims 7-9 and 18-20 further limit the compound of formula (Cz-
`)nMm to those having specific singlet or triplet energy gaps.
`
`• Claims 10 and 21 limit the claimed organic electroluminescent
`devices to those which emit “bluish” light.
`
`25
`
`RHEMK-1003.025
`
`
`
`• Claims 11 and 22 limit the claimed organic electroluminescent
`devices to those that operate based on a multiplet excitation to a
`
`triplet state or higher.
`
`41.
`
`I understand that the patent examiner who allowed these claim
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