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`IN THE UNITED STATES PATENT AND TRADEMARK OFFICE
`
`
`Al-Ali et al.
`In re Patent of:
`7,761,127 Attorney Docket No.: 50095-00046IP2
`U.S. Patent No.:
`July 20, 2010
`
`Issue Date:
`Appl. Serial No.: 11/366,209
`
`Filing Date:
`March 1, 2006
`
`Title:
`MULTIPLE WAVELENGTH SENSOR SUBSTRATE
`
`DECLARATION OF BRIAN W. ANTHONY, Ph.D.
`
`(Dietiker Grounds)
`
`
`
`1
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`APPLE 1003
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`
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`TABLE OF CONTENTS
`
`V.
`
`
`Background .................................................................................................. 11
`I.
`Level of Ordinary Skill in the Art ............................................................... 17
`II.
`Interpretations of the ’127 Patent Claims at Issue ....................................... 18
`III.
`IV. Overview of the Prior Art ............................................................................ 18
`A. Dietiker .............................................................................................. 18
`B.
`Oldham .............................................................................................. 21
`C.
`Leibowitz ........................................................................................... 24
`D. Noguchi ............................................................................................. 25
`E.
`Yamada ............................................................................................. 28
`The Dietiker-Oldham Combination ............................................................. 31
`A. Overview of the Combination ........................................................... 31
`B.
`Analysis ............................................................................................. 41
`1.
`Claim 7 .................................................................................... 41
`2.
`Claim 8 .................................................................................... 56
`3.
`Claim 9 .................................................................................... 58
`4.
`Claim 10 .................................................................................. 58
`VI. The Dietiker-Oldham-Leibowitz Combination ........................................... 61
`A. Overview of the Combination ........................................................... 61
`B.
`Analysis ............................................................................................. 63
`1.
`Claim 11 .................................................................................. 63
`2.
`Claim 12 .................................................................................. 65
`VII. The Dietiker-Oldham-Noguchi Combination .............................................. 66
`A. Overview of the Combination ........................................................... 66
`B.
`Analysis ............................................................................................. 70
`1.
`Claim 1 .................................................................................... 70
`2.
`Claim 2 .................................................................................... 75
`3.
`Claim 3 .................................................................................... 76
`
`2
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`
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`Claim 6 .................................................................................... 76
`4.
`Claim 13 .................................................................................. 76
`5.
`Claim 14 .................................................................................. 86
`6.
`Claim 15 .................................................................................. 87
`7.
`Claim 16 .................................................................................. 88
`8.
`Claim 17 .................................................................................. 88
`9.
`10. Claim 20 .................................................................................. 88
`11. Claim 21 .................................................................................. 89
`12. Claim 22 .................................................................................. 90
`13. Claim 23 .................................................................................. 90
`VIII. The Dietiker-Oldham-Noguchi-Leibowitz Combination ............................ 91
`A. Overview of the Combination ........................................................... 91
`B.
`Analysis ............................................................................................. 91
`1.
`Claim 4 .................................................................................... 91
`2.
`Claim 5 .................................................................................... 91
`3.
`Claim 18 .................................................................................. 92
`4.
`Claim 19 .................................................................................. 92
`5.
`Claim 24 .................................................................................. 92
`6.
`Claim 25 .................................................................................. 93
`IX. The Dietiker-Oldham-Noguchi-Yamada Combination ............................... 93
`A. Overview of the Combination ........................................................... 93
`B.
`Analysis ............................................................................................. 93
`1.
`Claim 26 .................................................................................. 93
`The Dietiker-Oldham-Noguchi-Yamada-Leibowitz Combination ............. 99
`A. Overview of the Combination ........................................................... 99
`B.
`Analysis ............................................................................................. 99
`1.
`Claim 28 .................................................................................. 99
`2.
`Claim 29 .................................................................................. 99
`XI. Legal Principles ......................................................................................... 100
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`X.
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`3
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`
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`A. Anticipation ..................................................................................... 100
`B.
`Obviousness .................................................................................... 100
`XII. Conclusion ................................................................................................. 102
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`4
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`
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`I, Brian W. Anthony, of Cambridge, MA, declare that:
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` My name is Dr. Brian W. Anthony. I am an Associate Principal
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`Research Scientist at the Institute of Medical Engineering & Science at
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`Massachusetts Institute of Technology (MIT). I am also a Principal Research
`
`Scientist at MIT’s Mechanical Engineering department, Director of the Master of
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`Engineering in Advanced Manufacturing and Design Program at MIT, Director of
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`Health Technology at the MIT Center for Clinical and Translational Research, a
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`Co-Director of the Medical Electronic Device Realization Center of the Institute of
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`Medical Engineering & Science, and Associate Director of MIT.nano. My current
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`curriculum vitae is attached and some highlights follow.
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`
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`I earned my B.S. in Engineering (1994) from Carnegie Mellon
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`University. I earned my M.S. (1998) and Ph.D. (2006) in Engineering from MIT.
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`My research focused on high-performance computation, signal processing, and
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`electro-mechanical system design.
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`
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`In 1997, I co-founded Xcitex Inc., a company that specialized in
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`video-acquisition and motion-analysis software. I served as the Chief Technology
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`Officer and directed and managed product development until 2006. Our first demo
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`product was an optical ring for human motion measurement used to capture user
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`hand motion in order to control the user’s interaction with a computer. Many of
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`the structural elements of our optical ring addressed the same system issues as
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`5
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`
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`those described and claimed in the patent at issue. For example, our optical ring
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`included multiple light emitting diodes, multiple photodetectors, techniques for
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`modulation and synchronization, and noise reduction algorithms. We estimated
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`human hand-motion based on how that motion changed the detected light. In our
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`application, we did not try to eliminate motion artifact, we tried to measure it. In
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`developing our ring, we considered well-known problems such as ambient light
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`and noise. Motion Integrated Data Acquisition System (MiDAS) was our flagship
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`video and data acquisition product which relied upon precise synchronization of
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`multiple clocks for optical sensor and video acquisition, data acquisition, and
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`external illumination.
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`
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`I joined MIT in 2006 and was the Director of the Master of
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`Engineering in Advance Manufacturing and Design Program for over ten years.
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`The degree program covers four main components: Manufacturing Physics,
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`Manufacturing Systems, Product Design, and Business Fundamentals. Many of
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`the courses, projects, and papers my students undertake involve technologies
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`relevant to the patent at issue, for example, sensor devices including non-invasive
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`optical biosensors.
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`
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`In 2011, I co-founded MIT’s Medical Electronic Device Realization
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`Center (“MEDRC”) and currently serve as co-director. The MEDRC aims to
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`create and deploy revolutionary medical technologies by collaborating with
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`6
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`clinicians, the microelectronics, and medical devices industries. We combine
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`expertise in computation; communications; optical, electrical, and ultrasound
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`sensing technologies; and consumer electronics. We focus on the usability and
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`productivity of medical devices using, for example, image and signal processing
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`combined with intelligent computer systems to enhance practitioners’ diagnostic
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`intuition. Our research portfolio includes low power integrated circuits and
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`systems, big data, micro electro-mechanical systems, bioelectronics, sensors, and
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`microfluidics. Specific areas of innovation include wearable, non-invasive and
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`minimally invasive optical biosensor devices, medical imaging, laboratory
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`instrumentation, and the data communication from these devices and instruments
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`to healthcare providers and caregivers. My experience with these devices is
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`directly applicable to the technology in the patent at issue.
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`
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`I am currently the Co-Director of the Device Realization Lab at the
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`Medical Electronic Device Realization Center at the Institute of Medical
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`Engineering & Science at MIT. The Device Realization Lab designs instruments
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`and techniques to sense and control physical systems. Medical devices and
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`manufacturing inspection systems are a particular focus. We develop and combine
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`electromechanical systems, complex algorithms, and computation systems to
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`create instruments and measurement solutions for problems that are otherwise
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`intractable.
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`7
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`The research of the Device Realization Lab focuses on product
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`development interests cross the boundaries of computer vision, acoustic and
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`ultrasonic imaging, large-scale computation and simulation, optimization,
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`metrology, autonomous systems, and robotics. We use computation, and computer
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`science, as methodology for attacking complex instrumentation problems. My
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`work combines mathematical modeling, simulation, optimization, and
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`experimental observations, to develop instruments and measurement solutions.
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` My record of professional service includes recognitions from several
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`professional organizations in my field of expertise.
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`
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`I am a named inventor on 10 issued U.S. patents. Most but not all of
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`these patents involve physiological monitoring and other measurement
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`technologies.
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`
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`I have published approximately 100 papers, and have received a
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`number of best paper and distinguished paper awards. A number of papers that I
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`have published relate to physiological monitoring and other measurement and
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`instrumentation technologies.
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`
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`I have been retained on behalf of Apple Inc. to offer technical
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`opinions relating to U.S. Patent No. 7,761,127 (“the ’127 Patent,” EX1001) and
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`prior art references relating to its subject matter. I have reviewed the ’127 Patent
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`and relevant excerpts of the prosecution history of the ’127 Patent (EX1002). I
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`8
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`
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`have also reviewed the following prior art references and materials, in addition to
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`other materials I cite in my declaration:
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`• U.S. Patent Publication No. 2003/0033102 (“Dietiker,” EX1009)
`
`• U.S. Patent Publication No. 2005/0279949 (“Oldham,” EX1010)
`
`• Certified English Translation of Japanese Patent Publication No. JP 2004-
`337605 A (“Yamada,” EX1004)
`
`• U.S. Patent No. 3,514,538 (“Chadwick,” EX1005)
`
`• U.S. Patent No. 4,591,659 to Leibowitz et al. (“Leibowitz,” EX1006)
`
`• U.S. Patent No. 5,259,381 (“Cheung,” EX1007)
`
`• U.S. Patent No. 5,334,916 to Noguchi et al. (“Noguchi,” EX1008)
`
`• J.A. Scarlett, The Multilayer Printed Circuit Board Handbook (1985)
`(selected excerpts) (“Scarlett,” EX1014)
`
`• Peltier Effect Heat Pumps Datasheet (March 1999) (EX1015)
`
` Counsel has informed me that I should consider these materials
`
`through the lens of one of ordinary skill in the art related to the ’127 Patent at the
`
`time of the earliest possible priority date of the ’127 Patent, and I have done so
`
`during my review of these materials. The application leading to the ’127 Patent
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`was filed on March 1, 2006 and claims the benefit of priority to four provisional
`
`applications, all filed March 1, 2005 (the “Critical Date”). Counsel has informed
`
`me that the Critical Date represents the earliest priority date to which the
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`9
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`
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`challenged claims of ’127 Patent are entitled, and I have therefore used that
`
`Critical Date in my analysis below.
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`
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`I have no financial interest in the party or in the outcome of this
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`proceeding. I am being compensated for my work as an expert on an hourly basis.
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`My compensation is not dependent on the outcome of these proceedings or the
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`content of my opinions.
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`
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`In writing this Declaration, I have considered the following: my own
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`knowledge and experience, including my work experience in the fields of
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`mechanical engineering, computer science, biomedical engineering, and electrical
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`engineering; my experience in teaching those subjects; and my experience in
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`working with others involved in those fields. In addition, I have analyzed various
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`publications and materials, in addition to other materials I cite in my declaration.
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` My opinions, as explained below, are based on my education,
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`experience, and expertise in the fields relating to the ’127 Patent. Unless otherwise
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`stated, my testimony below refers to the knowledge of one of ordinary skill in the
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`fields as of the Critical Date, or before. Any figures that appear within this
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`document have been prepared with the assistance of Counsel and reflect my
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`understanding of the ’127 Patent and the prior art discussed below.
`
`10
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`
`
`I.
`
`Background
` The ’127 patent, entitled “Multiple Wavelength Sensor Substrate,”
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`generally describes a “physiological sensor” that emits light towards a
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`measurement site on a patient, and measures physiological parameters such as
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`blood oxygen saturation or pulse rate. EX1001, Abstract, 2:49-65. The sensor
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`includes “emitter” components (e.g., light emitting diodes (LEDs)) used to emit
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`light into the measurement site, “detector” components (e.g., photodiodes,
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`phototransistors) that detect the reflected light and provide a corresponding signal
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`to a processor or other component representing the intensity of the reflected light,
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`and a “temperature sensor [] thermally coupled” to the emitters such that the
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`wavelengths of the emitted light “are determinable as a function of the drive
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`currents” and a “bulk temperature” of the emitters. Id., Abstract. Measurements
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`obtained with the sensors are dependent on the wavelengths of the emitted light,
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`which can vary as a function of both drive current and operating temperature.
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`According to the ‘127 Patent, measurement accuracy can be improved by tightly
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`controlling the wavelengths of emitted light or compensating for spectral shifts in
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`the wavelengths of emitted light due to changes in temperature, drive current, or
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`other factors. Figure 6 shows an example assembly 500 that includes “multiple
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`light emitting diodes (LEDs) 710” arranged on a substrate 1200:
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`11
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`
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`EX1001, FIG. 6; 6:47-63 (annotated)
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` The specification discloses that the substrate 1200 comprises a
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`“thermal mass … disposed proximate the emitters 710 so as to stabilize a bulk
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`temperature 1202 for the emitters.” Id., 10:22-31, FIG. 12. “A temperature sensor
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`1230 is thermally coupled to the thermal mass 1220, wherein the temperature
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`sensor 1230 provides a temperature sensor output 1232 responsive to the bulk
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`temperature 1202 …” Id. Figure 12 illustrates an embodiment in which (i) light
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`emitters 710 are positioned on one side of substrate 1200 / thermal mass 1220 and
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`(ii) temperature sensor 1230 [is] positioned on the other side:
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`12
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`EX1001, FIG. 12
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` Figures 14 depicts an additional embodiment of a substrate 1200 with
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`a thermal mass 1220. Id., 11:5-15, FIG. 14. In this embodiment, substrate 1200
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`includes “a component layer 1401, inner layers 1402-1405 and a solder layer
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`1406.” Id., 11:8-10. “The inner layers 1402-1405, e.g. inner layer 1402 (FIG. 18),
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`have substantial metallized areas 1411 that provide a thermal mass 1220 (FIG. 12)
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`to stabilize a bulk temperature for the emitter array 700 (FIG. 12).” Id. 11:10-13.
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`13
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`EX1001, FIG. 14 (annotated)
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`
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`Independent claims 1, 7, and 13 of the ’127 patent are representative
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`
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`of the features described above:
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`1. A physiological sensor comprising:
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`a plurality of emitters configured to transmit optical radiation
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`having a plurality of wavelengths in response to a corresponding
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`plurality of drive currents, the plurality of emitters including a
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`substrate;
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`a thermal mass disposed proximate the emitters and within the
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`substrate so as to stabilize a bulk temperature for the emitters; and
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`a temperature sensor thermally coupled to the thermal mass,
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`14
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`
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`wherein the temperature sensor provides a temperature sensor
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`output responsive to the bulk temperature so that the wavelengths
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`are determinable as a function of the drive currents and the bulk
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`temperature.
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`7. A physiological sensor capable of emitting light into tissue
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`and producing an output signal usable to determine one or more
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`physiological parameters of a patient, the physiological sensor
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`comprising:
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`a thermal mass;
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`a plurality of light emitting sources, including a substrate of
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`the plurality of light emitting sources, thermally coupled to the
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`thermal mass, the sources having a corresponding plurality of
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`operating wavelengths, the thermal mass disposed within the
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`substrate;
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`a temperature sensor thermally coupled to the thermal mass
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`and capable of determining a bulk temperature for the thermal
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`mass, the operating wavelengths dependent on the bulk
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`temperature; and
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`15
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`
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`a detector capable of detecting light emitted by the light
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`emitting sources after tissue attenuation, wherein the detector is
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`capable of outputting a signal usable to determine one or more
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`physiological parameters of a patient based upon the operating
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`wavelengths.
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`13.
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`In a physiological sensor adapted
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`to determine a
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`physiological parameter using a plurality of light emitting sources
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`with emission wavelengths affected by one or more dynamic
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`operating parameters, a sensor method comprising:
`
`providing a thermal mass disposed within the substrate
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`proximate the light emitting sources and a temperature sensor
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`thermally coupled to the thermal mass;
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`transmitting optical radiation from the plurality of light
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`emitting sources into body tissue;
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`detecting the optical radiation after tissue attenuation; and
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`determining a plurality of operating wavelengths of the light
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`emitting sources dependent on a bulk temperature of the light
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`emitting sources so that one or more physiological parameters of
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`16
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`
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`a patient can be determined based upon
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`the operating
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`wavelengths.
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`
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`II. Level of Ordinary Skill in the Art
` Based on the foregoing and upon my experience in this area, a person
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`of ordinary skill in the art as of the Critical Date of the ’127 patent (a “POSITA”)
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`would have had a Bachelor of Science degree in an academic discipline
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`emphasizing the design of electrical and thermal technologies, in combination with
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`training or at least one to two years of related work experience with the capture and
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`processing of data or information, including physiological monitoring
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`technologies. Alternatively, a POSITA could have had a Master of Science degree
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`in a relevant academic discipline with less than a year of related work experience
`
`in the same discipline.
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` Based on my experiences, I have a good understanding of the
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`capabilities of a POSITA. Indeed, I have taught, participated in organizations, and
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`worked closely with many such persons over the course of my career.
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`
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`I have performed my analysis through the lens of a POSITA as of the
`
`Critical Date.
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`17
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`
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`III.
`
`Interpretations of the ’127 Patent Claims at Issue
`
`I understand that, for purposes of my analysis in this inter partes
`
`review proceeding, the terms appearing in the patent claims should generally be
`
`interpreted according to their “ordinary and customary meaning.” See Phillips v.
`
`AWH Corp., 415 F.3d 1303, 1312 (Fed. Cir. 2005) (en banc). I understand that
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`“the ordinary and customary meaning of a claim term is the meaning that the term
`
`would have to a person of ordinary skill in the art in question at the time of the
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`invention.” Id. at 1313. I also understand that the person of ordinary skill in the
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`art is deemed to read the claim term not only in the context of the particular claim
`
`in which the disputed term appears, but in the context of the entire patent,
`
`including the specification. Id.
`
`IV. Overview of the Prior Art
`A. Dietiker
` Dietiker teaches “a blood constituent monitoring system and/or a non-
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`invasive oximeter that may be utilized to monitor arterial oxygen saturation.”
`
`EX1009, [0005], [0033]. The monitoring system includes a probe 102, which in
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`turn includes a “first light source 204” and a “second light source 206” configured
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`to emit optical radiation at different wavelengths from each other. EX1009,
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`[0032]. The probe 102 further includes a wavelength sensor 202 such as a “double
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`diffusion photodiode” configured to output a signal indicative of the amount of
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`incident light radiation detected from light sources 204, 206. Id., [0035]. “The
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`18
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`
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`oximeter utilizes the measured incident light radiation received by wavelength
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`sensor 202 to determine the operating wavelength of the first light source 204,”
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`from which it then “determine[s] [the] blood oxygen saturation of [a] material 308”
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`such as a finger or other tissue measurement site of a person. Id., [0034]-[0035];
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`see also id., [0006], [0032], [0047].
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`
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`EX1009, FIG. 2 (cropped and annotated)
`
` Dietiker further teaches that "non-invasive sensor systems utilizing a
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`coherent light source require accurate prior knowledge of the wavelength of the
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`coherent light source in order to determine the amount of coherent light that is
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`absorbed or reflected through the target." Id., [0007]. This is important because,
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`among other things, "a relatively small variation in operating wavelength may
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`19
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`
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`result in inaccurate readings at the oximeter." Id., [0036]. In this context, Dietiker
`
`acknowledges the well-known phenomenon that the emission wavelength of an
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`LED can drift from its nominal/target wavelength due to variances in production
`
`factors as well as operating conditions-including the "temperature" of the LED.
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`Id., [0007]-[0008], [0060].
`
` To improve measurement accuracy, Dietiker thus proposed a "self-
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`calibration procedure" that could be performed before obtaining measurements of
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`light reflected from a tissue or other material. The self-calibration procedure
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`allows the operating wavelength of the first light source 204 to be determined so
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`that subsequent measurements can be made accounting for the actual wavelength
`
`of light source 204 rather than its nominal/presumed wavelength. Id., [0040],
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`[0044] (describing self-calibration procedure), [0052]-[0055] & FIGS. 8-9
`
`(describing techniques for measuring the operating wavelength with a double-
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`diffusion photodiode (wavelength sensor 202)). While the self-calibration
`
`technique can be used to compensate for production-induced emission variances in
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`LEDs, Dietiker also explicitly teaches that self-calibration can similarly be
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`performed temperature-induced fluctuations in the emission wavelength of an
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`LED. Id., [0060].
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`20
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`
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`B. Oldham
` Like Dietiker, Oldham confronted the problem of temperature-
`
`induced spectral shifts in optical instruments whose measurement accuracy or
`
`efficacy depends on the precise wavelengths of emitted light. EX1010, [0002]-
`
`[0003]. To mitigate temperature-induced spectral shifts, Oldham proposed a
`
`temperature regulation system to control heating and cooling of LEDs such that
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`their operating temperatures are stabilized or otherwise maintained within an
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`acceptable/defined temperature range. EX1010, [0004], [0016]-[0023].
`
` For example, embodiments of Oldham’s temperature-regulated
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`instrument include an array 110/210 of LEDs 111/211, a substrate 112/212, a
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`temperature sensor 118/218, a temperature regulator 122/222, cooling fins
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`104/204, and a heat-transfer device such as a fan 114 and heater 116 (FIG. 1) or
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`thermoelectric device (e.g., Peltier device) 214 (FIG. 2). Oldham’s instrument can
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`further include photodiodes for sensing light emitted from the LED array 110/210
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`(e.g., after the light has passed through one or more other materials). Id., [0031],
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`[0036].
`
`
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`In more detail, Oldham describes that:
`
`The temperature sensor can be in thermal contact
`
`with the LED, can be capable of measuring an operating
`temperature, and can be capable of generating an
`operating temperature signal. The temperature regulator
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`21
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`
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`can be capable of receiving an operating temperature
`signal of the LED and regulating the operating
`temperature based on the operating temperature signal.
`
`
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`EX1010, [0004], see also [0042] (“optical detection instruments utilizing LEDs
`
`can obtain very stable intensity or spectral characteristics by stabilizing an
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`operating temperature of an LED”), [0018] (“The temperature regulator can be
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`adapted such that it is capable of maintaining the operating temperature within an
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`operating temperature range including a minimum temperature and a maximum
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`temperature.”).
`
` Figures 1 and 2 respectively illustrate two embodiments of Oldham’s
`
`temperature regulation devices. As shown below, the heat-transfer mechanism in
`
`the Figure 1 embodiment includes a heater 116 disposed within substrate 112 and
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`“in thermal contact” with LEDs 111, along with a fan 114 that directs an air
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`current over cooling fins 104 in thermal contact with substrate 112:
`
`22
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`
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`EX1010, FIG. 1 (annotated); see also id., [0024]
`
`
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`In lieu of fan 114 and heating device 116 of Figure 1, Oldham’s
`
`Figure 2 embodiment employs a thermoelectric device 214 (e.g., a Peltier device)
`
`in thermal contact with substrate 212 to direct heat toward or away from LED
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`array 210:
`
`EX1010, FIG. 2 (annotated); see also id., [0025]
`
`
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`23
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`
`
`C. Leibowitz
` Leibowitz, a U.S. patent filed in 1983, describes “a multilayered
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`printed circuit board structure in which multiple layers of graphite are employed …
`
`to provide enhanced thermal conductivity.” EX1006, 2:30-34. Leibowitz
`
`recognized that “as larger numbers of components are mounted on circuit boards,
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`… the heat produced by the components must be dissipated in some manner,” but
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`“[s]ince the principal materials used in circuit boards are insulators, the boards
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`have traditionally played no significant role in dissipating heat from the
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`components that they support.” EX1006, 1:56-64. To address this, and other
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`problems with traditional circuit boards, Leibowitz proposed a multilayer PCB
`
`having “good thermal conduction properties to enhance conduction from devices
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`mounted on the board.” Id., 2:24-27.
`
` Figure 2 illustrates an embodiment of Leibowitz’s PCB. As shown
`
`below, Leibowitz’s “circuit board 10 includes a plurality of layers of graphite 16
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`interleaved between layers 18 of a dielectric material,” where “[s]ome of the layers
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`18 are copper coated, as indicated at 20.” Id., 3:56-61. “The PTFE
`
`[polytetrafluoroethylene] layers 18 provide the basic dielectric material of the
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`board 10, and the graphite layers 16 provide both thermal conductivity and control
`
`of thermal coefficient of expansion.” Id., 3:61-65.
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`24
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`
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`EX1006, FIG. 2 (annotated)
`
`D. Noguchi
` Noguchi teaches techniques for “controlling the emission spectrum of
`
`an LED with high precision,” including determining the wavelength of light
`
`emitted by the LED based on (1) a measured temperature and (2) a measured level
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`of current or voltage driving the LED. EX1008, 1:7-12, 2:50-3:14, 1:33-50. For
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`example, Noguchi explains the following:
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`
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`The temperature of the LED itself or the
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`surrounding ambient temperature and the driving
`power of the LED are detected. Then, the emission
`wavelength energy can be calculated by subtracting
`the value of an applied power multiple by a
`specified coefficient and the difference from the
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`25
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`
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`temperature multiple by a specified
`standard
`coefficient from the optical band gap at the standard
`temperature.
`EX1008, 2:2-10 (emphasis added)
`
` Noguchi explains how “[t]he temperature of the LED is measured by
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`a temperature sensor,” although “the temperature to be measured is not limited to
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`the temperature of the LED itself, but the temperature in the environment
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`surrounding the LED can also be measured.” EX1006, 2:20-29. Furthermore,
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`“[t]he number of LEDs or sensors used in the present invention can be more than
`
`one each.” Id., 2:30-41.
`
` Figure 1 is a block diagram of an example system for “LED emission
`
`spectrum control”:
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`26
`
`
`
`EX1008, FIG. 1
`
`
`
` As shown above, “1 is an LED with a sensor for measuring
`
`temperature, 2 is a measurement and control means for an LED driving current, 3
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`is a measurement and control means for an LED applied voltage, 4 is a
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`measurement means for an LED temperature, 5 is a computing unit, and 6 is a
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`control means for an emission wavelength.” Id., 2:14-19. The computing unit 5
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`receives inputs indicating the measured temperature of the LED 1, the driving
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`voltage of the LED 1, and driving current of the LED 1, and processes these inputs
`
`to calculate the present wavelength of light emitted from LED 1. Id., 3:15-38, FIG.
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`3. Control means 6 then uses the calculation of the present wavelength to adjust
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`27
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`
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`the driving current of the LED 1 to correspondingly adjust the wavelength of
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`emitted light toward a desired/target value. Id., 3:39-47, FIG. 4.
`
`E. Yamada
` Yamada describes an optical sensor that “detects light (reflected light)
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`that has been directed toward the surface of the human body, scattered inside the
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`human body, and returned toward the exposed surface.” EX1004, [0001]-[0002].
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`An example of such an optical sensor is a pulse oximeter used to measure the
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`oxygen saturation of blood. Id. Other uses can include measurement of blood
`
`glucose or measurement of sugar content in food produce. EX1004, [0106].
`
` Yamada recognized a problem with prior optical sensors “in that the
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`LED used to emit light also generates heat, and the patient is exposed to this heat
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`because the optical sensor is attached to the surface of a fingernail.” Id., [0005].
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`“As a result, the exposure time and power consumption (that is, the amount of light
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`generated) have to be limited in order to suppress the amount of heat that is
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`generated.” Id. To overcome this issue, Yamada proposed a design for an optical
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`sensor that was intended to reduce the amount of heat to which the subject wearing
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`the device is exposed. Id., [0001]-[0005]. This optical sensor disclosed in Yamada
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`includes “a light emitting unit 11 (including LEDs 111, 112), a light receiving unit
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`12, a