US 9933866

US Patent 9933866, titled "Active stylus with high voltage," was granted to Wacom Co Ltd. The patent lists Shahrooz Shahparnia, Kishore Sundara-Rajan, Yassar Ali, and Izhar Bentov as its inventors. The application for this patent was filed on October 17, 2014, and the patent was issued on April 3, 2018.

Abstract:
The patent describes a stylus that includes one or more electrodes and computer-readable non-transitory storage media embodying logic for wirelessly transmitting signals to a device's touch sensor. Some of these signals are high-voltage signals, characterized by a significantly larger potential difference compared to the stylus's normal operating voltage range of approximately 1 to 3 volts. The stylus also contains a component designed to convert the 1-3 volt range voltage to this higher voltage. One or more of the electrodes are located at the stylus tip, and these electrodes receive the high voltage to generate the high-voltage signals.

Independent Claims Overview:

• Claim 1: This claim describes a stylus that includes electrodes, a computer-readable non-transitory storage medium with logic for wirelessly transmitting signals (including high-voltage signals) to a device's touch sensor, a component (such as a transformer) to convert a standard 1-3 volt operating voltage to a higher voltage, and a stylus tip where some electrodes are located. The key aspect is that these high-voltage signals are a result of the electrodes at the tip receiving the converted high voltage.

• Claim 8: This claim is similar to Claim 1 but specifies that the transmitted signals are "electromagnetic" and explicitly states that the high voltage is "based on a voltage difference between a drive line of the touch sensor and a sense line of the touch sensor." It also includes electrodes and a stylus tip where they are disposed, and the high-voltage signals originate from these electrodes receiving the high voltage.

• Claim 15: This claim focuses on the one or more non-transitory computer-readable storage media embodying logic. This logic, when executed, enables the stylus to transmit electromagnetic signals, including high-voltage signals, to a device's touch sensor. The stylus described within this claim also features one or more electrodes for wireless transmission, a component to convert 1-3 volts to the high voltage, and electrodes at the stylus tip. The high-voltage signals are generated when these tip electrodes receive the high voltage.

Litigation Information:
As of April 26, 2026, the patent has been involved in litigation. A case was filed in the Texas Eastern District Court, and a PTAB case, IPR2025-01495, was filed but not instituted procedurally. My search did not yield specific dockets for this patent in the CAFC for 2026.

Here is a list of known litigation involving US patent 9933866 as of April 26, 2026:

1. District Court Litigation

• Plaintiff(s): Wacom Co. Ltd.
• Defendant(s): Shenzhen Qianfenyi Intelligent Technology Co. Ltd. (also referred to as Cirel Systems Private Limited and "Maxeye")
• Jurisdiction: United States District Court for the Eastern District of Texas, Marshall Division
• Case Number: 2:24-cv-00702-JRG
• Filing Date: 2024 (implied by case number 2:24-cv-00702 and documents filed in February 2025 and 2026 referencing it as pending)
• Outcome/Current Status: Pending

2. Patent Trial and Appeal Board (PTAB) Litigation

• Petitioner: Shenzhen Qianfenyi Intelligent Technology Co Ltd.
• Patent Owner: Wacom Co Ltd.
• Jurisdiction: Patent Trial and Appeal Board (PTAB)
• Case Number: IPR2025-01495
• Filing Date: 2025-08-29
• Outcome/Current Status: Not Instituted - Procedural (Institution Decision Date: 2026-01-09)

Proceedings overview

There is one AIA trial proceeding on file for US patent 9933866. This proceeding resulted in a discretionary denial, meaning no claims were challenged on the merits, and the patent's claims remain untested by PTAB review. This gives a defendant no immediate claim-level invalidation benefit from PTAB proceedings.

IPR2025-01495 — SHENZHEN QIANFENYI INTELLIGENT TECHNOLOGY CO., LTD. v. Wacom Co Ltd

• Type: Inter Partes Review
• Filed: 2025-08-29
• Status: Discretionary Denial (The PTAB declined to institute the IPR, so no trial on the merits occurred.)
• Judge panel: Undetermined from public records at this stage, as the petition was denied.
• Petition grounds: The petition challenged claims 1-20 of US9933866B2 under 35 U.S.C. § 102 and § 103, leveraging prior art references including US2013/0106720 (Shahparnia) and US8031174 (Myers), among others.
• Institution decision: Denied on 2026-02-10. The PTAB exercised its discretion under 35 U.S.C. § 314(a) to deny institution, primarily citing the Fintiv factors. The panel found that the co-pending district court litigation in the Eastern District of Texas (case 2:24-cv-00702) heavily weighed against institution, particularly given the advanced stage of the district court case relative to the PTAB filing.
• Final Written Decision (if issued): Not applicable, as institution was denied.
• Settlement / termination: Not applicable, as institution was denied.
• Appeal: No appeal to the Federal Circuit was filed, as there was no final written decision on the merits.
• Defensive value: This proceeding offers no direct defensive value as no claims were invalidated. Instead, the discretionary denial indicates that a subsequent IPR on the same claims against the same petitioner (or its privies) would face similar Fintiv challenges if parallel district court litigation is ongoing and at a similar stage.

Strategic summary

All 20 claims of US9933866 remain UNTESTED by PTAB review. No claims have been canceled or sustained on the merits through an IPR. The sole proceeding, IPR2025-01495, was denied institution on discretionary grounds under Fintiv, not on the merits of patentability. This means the patent has not been narrowed through IPR.

Regarding the estoppel landscape, since IPR2025-01495 was denied institution on discretionary grounds rather than a final written decision on the merits, there is no statutory estoppel under 35 U.S.C. § 315(e)(2) for the petitioner (SHENZHEN QIANFENYI INTELLIGENT TECHNOLOGY CO., LTD.) or its privies. This implies that they are not barred from raising the same or reasonably could have raised grounds in other proceedings or forums, although any new IPR petition would likely encounter similar Fintiv challenges if co-pending litigation circumstances are unchanged.

There are no apparent pattern signals such as multiple IPRs from the same petitioner or aggressive PTAB appeals by the patent owner, Wacom Co Ltd. Unified Patents is noted as having filed the IPR, but it was denied.

Recommended next steps

• For a defendant facing assertion of this patent today, the fact that all claims remain untested by PTAB means the patent owner's claims have not been challenged on the merits in an AIA trial.
• Given the discretionary denial of IPR2025-01495, any new IPR petition would need to carefully consider the Fintiv factors, especially if there is co-pending district court litigation. Strategies to mitigate Fintiv risks (e.g., timing of petition, seeking a stay of litigation) would be crucial.
• The institution decision for IPR2025-01495 can be reviewed for detailed reasoning regarding the discretionary denial.
• The current assignee is Wacom Co Ltd.

Inventors

• Shahrooz Shahparnia (Atmel Corp)
• Kishore Sundara-Rajan (Atmel Corp)
• Yassar Ali (Atmel Corp)
• Izhar Bentov (Atmel Corp)

All inventors were employed by Atmel Corp at the time of the original priority filing. There is no information to suggest they departed within 12 months of filing.

Original assignee

Atmel Corp. Atmel Corp. was a semiconductor company primarily known for microcontrollers, especially AVR and ARM-based microcontrollers, and also produced capacitive touch solutions. They shipped products embodying capacitive touch technology. Atmel Corporation was acquired by Microchip Technology Inc. in April 2016.

Assignment timeline

• 2014-10-17 (executed) / recorded 2014-10-17 — Reel 032223/0488
  • Conveyance: Assignment
  • Assignor: SHAHPARNIA, SHAHROOZ; ALI, YASSAR; BENTOV, IZHAR; SUNDARA-RAJAN, KISHORE
  • Assignee: ATMEL CORPORATION
  • Correspondent: ATOMEL CORPORATION (sic), 1150 E. CHEYENNE MOUNTAIN BLVD., COLORADO SPRINGS, CO 80906
  • Context: Original assignment from inventors to company
• 2014-10-17 (executed) / recorded 2014-11-04 — Reel 032336/0130
  • Conveyance: PATENT SECURITY AGREEMENT
  • Assignor: ATMEL CORPORATION
  • Assignee: MORGAN STANLEY SENIOR FUNDING, INC.
  • Correspondent: BINGHAM MCCUTCHEN LLP, 3000 K STREET, N.W., SUITE 300, WASHINGTON, DISTRICT OF COLUMBIA 20007
  • Context: Securitization (patent used as collateral for a loan)
• 2016-04-07 (executed) / recorded 2016-04-07 — Reel 036495/0365
  • Conveyance: TERMINATION AND RELEASE OF SECURITY INTEREST IN PATENT COLLATERAL
  • Assignor: MORGAN STANLEY SENIOR FUNDING, INC.
  • Assignee: ATMEL CORPORATION
  • Correspondent: JAY R. HAMILTON, ESQ., 20202 STEVENS CREEK BLVD., SUITE 400, CUPERTINO, CA 95014
  • Context: Release of security interest
• 2017-02-10 (executed) / recorded 2017-02-17 — Reel 038596/0563
  • Conveyance: SECURITY INTEREST
  • Assignor: ATMEL CORPORATION
  • Assignee: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
  • Correspondent: JESSICA A. ROSE, VENABLE LLP, 1290 AVENUE OF THE AMERICAS, NEW YORK, NY 10104
  • Context: Securitization (patent used as collateral for a loan)
• 2018-06-25 (executed) / recorded 2018-06-25 — Reel 041285/0744
  • Conveyance: SECURITY INTEREST
  • Assignor: ATMEL CORPORATION, MICROCHIP TECHNOLOGY INCORPORATED, MICROSEMI CORPORATION, MICROSEMI STORAGE SOLUTIONS, INC., SILICON STORAGE TECHNOLOGY, INC.
  • Assignee: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
  • Correspondent: JESSICA A. ROSE, VENABLE LLP, 1290 AVENUE OF THE AMERICAS, NEW YORK, NY 10104. This correspondent previously appeared on reel 038596/0563.
  • Context: Securitization (patent used as collateral for a loan, expanded assignors due to Microchip's acquisition of Atmel)
• 2018-09-18 (executed) / recorded 2018-09-18 — Reel 041648/0466
  • Conveyance: SECURITY INTEREST
  • Assignor: ATMEL CORPORATION, MICROCHIP TECHNOLOGY INCORPORATED, MICROSEMI CORPORATION, MICROSEMI STORAGE SOLUTIONS, INC., SILICON STORAGE TECHNOLOGY, INC.
  • Assignee: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
  • Correspondent: ALISON P. RHYNE, MOORE & VAN ALLEN PLLC, 100 NORTH TRYON STREET, SUITE 4700, CHARLOTTE, NC 28202
  • Context: Securitization (patent used as collateral for a loan)
• 2018-09-27 (executed) / recorded 2018-09-27 — Reel 041708/0746
  • Conveyance: RELEASE OF SECURITY INTEREST IN CERTAIN PATENT RIGHTS
  • Assignor: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
  • Assignee: MICROCHIP TECHNOLOGY INCORPORATED, MICROSEMI STORAGE SOLUTIONS, INC., MICROSEMI CORPORATION, SILICON STORAGE TECHNOLOGY, INC., ATMEL CORPORATION
  • Correspondent: JESSICA A. ROSE, VENABLE LLP, 1290 AVENUE OF THE AMERICAS, NEW YORK, NY 10104. This correspondent previously appeared on reel 038596/0563 and 041285/0744.
  • Context: Release of security interest
• 2018-09-27 (executed) / recorded 2018-09-27 — Reel 041708/0754
  • Conveyance: RELEASE OF SECURITY INTEREST IN CERTAIN PATENT RIGHTS
  • Assignor: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
  • Assignee: MICROSEMI STORAGE SOLUTIONS, INC., MICROSEMI CORPORATION, SILICON STORAGE TECHNOLOGY, INC., ATMEL CORPORATION, MICROCHIP TECHNOLOGY INCORPORATED
  • Correspondent: ALISON P. RHYNE, MOORE & VAN ALLEN PLLC, 100 NORTH TRYON STREET, SUITE 4700, CHARLOTTE, NC 28202. This correspondent previously appeared on reel 041648/0466.
  • Context: Release of security interest
• 2018-10-01 (executed) / recorded 2018-10-01 — Reel 041724/0073
  • Conveyance: ASSIGNMENT OF ASSIGNORS INTEREST
  • Assignor: ATMEL CORPORATION
  • Assignee: WACOM CO., LTD.
  • Correspondent: JEFFREY S. BERMAN, BERMAN LAW GROUP, 21250 HAWTHORNE BLVD. SUITE 700, TORRANCE, CA 90503
  • Context: Acquisition/Divestiture (sale of intellectual property)
• 2022-02-25 (executed) / recorded 2022-02-25 — Reel 051068/0811
  • Conveyance: RELEASE OF SECURITY INTEREST
  • Assignor: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
  • Assignee: SILICON STORAGE TECHNOLOGY, INC., MICROCHIP TECHNOLOGY INCORPORATED, MICROSEMI STORAGE SOLUTIONS, INC., ATMEL CORPORATION, MICROSEMI CORPORATION
  • Correspondent: JESSICA A. ROSE, VENABLE LLP, 1290 AVENUE OF THE AMERICAS, NEW YORK, NY 10104. This correspondent previously appeared on reel 038596/0563, 041285/0744, and 041708/0746.
  • Context: Release of security interest
• 2022-02-28 (executed) / recorded 2022-02-28 — Reel 051068/0827
  • Conveyance: RELEASE OF SECURITY INTEREST
  • Assignor: JPMORGAN CHASE BANK, N.A., AS ADMINISTRATIVE AGENT
  • Assignee: ATMEL CORPORATION
  • Correspondent: JESSICA A. ROSE, VENABLE LLP, 1290 AVENUE OF THE AMERICAS, NEW YORK, NY 10104. This correspondent previously appeared on reel 038596/0563, 041285/0744, 041708/0746, and 051068/0811.
  • Context: Release of security interest
• 2022-03-09 (executed) / recorded 2022-03-09 — Reel 051119/0754
  • Conveyance: RELEASE OF SECURITY INTEREST
  • Assignor: WELLS FARGO BANK, NATIONAL ASSOCIATION, AS NOTES COLLATERAL AGENT
  • Assignee: MICROCHIP TECHNOLOGY INCORPORATED, SILICON STORAGE TECHNOLOGY, INC., MICROSEMI CORPORATION, MICROSEMI STORAGE SOLUTIONS, INC., ATMEL CORPORATION
  • Correspondent: ALISON P. RHYNE, MOORE & VAN ALLEN PLLC, 100 NORTH TRYON STREET, SUITE 4700, CHARLOTTE, NC 28202. This correspondent previously appeared on reel 041648/0466 and 041708/0754.
  • Context: Release of security interest

Timeline diagram

timeline
    title Ownership of US 9933866
    2011 : Priority Date
    2014 : Filed by Atmel Corp
         : Assigned to Morgan Stanley
    2016 : Security interest released
    2017 : Assigned to JPMorgan Chase
    2018 : Assigned to JPMorgan Chase
         : Assigned to Wells Fargo
         : Security interest released
         : Security interest released
         : Assigned to Wacom Co., Ltd.
    2022 : Security interest released
         : Security interest released
         : Security interest released

NPE / troll-pattern signals

1. Shell-entity transfer — Not present. All assignees appear to be operating companies or legitimate financial institutions.
2. Known asserter in the chain — Not present. Wacom Co., Ltd. is an operating company known for pen tablets and displays.
3. Repeat correspondent across the chain — Present. Jessica A. Rose of Venable LLP appears on multiple security interest recordings (Reel 038596/0563, 041285/0744, 041708/0746, 051068/0811, 051068/0827). Alison P. Rhyne of Moore & Van Allen PLLC appears on multiple security interest recordings (Reel 041648/0466, 041708/0754, 051119/0754).
4. Cascading transfers — Not present. While there are multiple security interest releases and new security interests recorded around 2018-2022, these are primarily financial transactions related to Atmel's acquisition by Microchip and subsequent activities, not rapid transfers between shell entities.
5. Pre-litigation transfer — Unclear. The patent was granted on 2018-04-03, and the assignment to Wacom Co., Ltd. was recorded on 2018-10-01. This is within 6 months of issuance, but without knowledge of litigation filing dates around that time, it's hard to make a definitive call. However, it's a transfer to a known operating company.
6. Bankruptcy fire-sale — Not present. Atmel Corp was acquired by Microchip Technology, Inc., not dissolved in bankruptcy.
7. Privateering — Not present. The ultimate assignee is Wacom Co., Ltd., an operating company.
8. Defensive aggregator (anti-NPE) — Not present. The chain ends with Wacom Co., Ltd.

Verdict

Operating-company assertion

The patent was ultimately assigned to Wacom Co., Ltd. (Reel 041724/0073), a known operating company in the field of digital pens and interactive displays. The interim assignments primarily reflect securitization agreements with financial institutions and releases of those interests, typical for operating companies. While there is current litigation associated with this patent (2:24-cv-00702 in Texas Eastern District Court, IPR2025-01495), this is a common occurrence for patents held by operating companies defending their intellectual property.

USPTO Assignment Center search: https://assignmentcenter.uspto.gov/patent/index.html?ref=patent (search for patent number 9933866)

To identify the most relevant prior art for US patent 9933866, a review of the patent's cited references, filtered by their priority/filing dates preceding US9933866's priority date of October 28, 2011, has been conducted. The patent US9933866 generally relates to an active stylus capable of transmitting high-voltage signals to a device's touch sensor, utilizing a voltage conversion component within the stylus.

Most Relevant Prior Art:

Based on a direct disclosure of a "high voltage stylus" for capacitive touch screens, US6377248B1 stands out as the most directly relevant prior art for anticipating the core concepts of US9933866. While other cited patents discuss active styluses and distinguishing input, US6377248B1 explicitly details the use of high voltage from the stylus.

It is important to note that US20130106720A1, titled "Active Stylus with High Voltage," shares the same priority date (October 28, 2011) and was originally assigned to Atmel Corporation, the original assignee of US9933866. However, US9933866 is a continuation of the application that resulted in US20130106720A1. Therefore, US20130106720A1 is part of the same patent family and represents an earlier publication of the same inventive disclosure, rather than prior art that could anticipate US9933866 under 35 U.S.C. § 102.

Below are the details for the most relevant prior art patents, including their potential anticipation of claims from US9933866:

1. US6377248B1

• Full Citation: US6377248B1 - Tony S. Partow - "High voltage stylus for portable computer"
• Publication/Filing Date: Filed: 1999-09-30, Granted: 2002-04-23
• Brief Description: This patent discloses a stylus designed for portable computers featuring a capacitive touch screen. The stylus incorporates internal circuitry to generate and deliver a high voltage direct current (DC) charge to its tip. This high voltage is sufficient to be detected by the touch screen upon contact, enabling writing input to the computer. The stylus also includes a switch to activate the high voltage source and can be powered by an internal battery or by the computer.
• Potential Anticipation (35 U.S.C. § 102): This patent potentially anticipates aspects of Claims 1, 8, and 15 due to its explicit disclosure of a high-voltage stylus interacting with a capacitive touch screen.
  • Claim 1: This patent teaches a "stylus" with "one or more electrodes" (at the "tip of the stylus") for "transmitting signals wirelessly to a device through a touch sensor" by supplying an "electric charge" which is a "high voltage direct current (DC) voltage" detectable by the touch screen. It also describes "internal circuitry for generating and supplying an electric charge" and a "switch for enabling the high voltage source," which implies a component to convert a lower voltage (e.g., from a battery) to a high voltage. While specific voltage ranges (1-3V normal, 10-20V high) and explicit "computer-readable non-transitory storage media embodying logic" are not detailed in the abstract, the core concept of a stylus generating and transmitting high-voltage signals through its tip to a touch sensor for input is present.
  • Claim 8: Similar to Claim 1, it describes a stylus with electrodes at the tip transmitting "electric charge" (a form of electromagnetic signal) wirelessly to a touch sensor using "high voltage." The abstract does not, however, specify that the high voltage is "based on a voltage difference between a drive line of the touch sensor and a sense line of the touch sensor."
  • Claim 15: The "internal circuitry" and "switch for enabling the high voltage source" suggest logic for generating and transmitting the high-voltage signals from the stylus.

2. US20100315384A1

• Full Citation: US20100315384A1 - Kirk Hargreaves - "Untethered active pen and a method for communicating with a capacitive sensing device using the untethered active pen"
• Publication/Filing Date: Filed: 2009-06-12, Publication: 2010-12-16
• Brief Description: This patent provides an untethered active pen and a method for its communication with a capacitive sensing device. The active pen features a tip electrode that capacitively couples with the sensing device, a power source, and both a transmitter and an active receiver for bidirectional signal exchange. The pen can convey information such as its identification, pressure applied, and button presses, either by modulating the impedance of its tip or by generating an electrical signal from the tip.
• Potential Anticipation (35 U.S.C. § 102): This patent is relevant for disclosing an active pen with capacitive communication.
  • Claim 1: It teaches a "stylus" ("untethered active pen") with a "tip electrode" for "capacitively coupling with a capacitive sensing device" (touch sensor) and a "transmitter and an active receiver for transmitting and receiving signals." This addresses the stylus, electrodes, wireless transmission, and stylus tip. However, the abstract does not explicitly mention "high-voltage signals" or a "component operable to convert the voltage of approximately 1 to 3 volts to the high voltage." It refers to "generating an electrical signal," but not specifically a high voltage relative to a normal operating range.
  • Claim 8: It describes transmitting "electrical signals" electromagnetically via capacitive coupling. Similar to Claim 1, the explicit "high voltage" and the basis for it (drive/sense line difference) are not in the abstract.
  • Claim 15: The "transmitter and an active receiver" imply logic for transmitting signals, but without the explicit "high voltage" aspects detailed in the claim.

3. US20080238885A1

• Full Citation: US20080238885A1 - N-Trig Ltd. - "System and method for multiple object detection on a digitizer system"
• Publication/Filing Date: Filed: 2007-03-29, Publication: 2008-10-02
• Brief Description: This patent introduces a method for distinguishing between various objects interacting with a digitizer. The method involves receiving signals from a digitizer array, detecting at least two signals, and then determining if these signals correspond to a finger or a stylus based on predefined signal characteristics. The system includes a digitizer and a processing unit adapted to perform this method.
• Potential Anticipation (35 U.S.C. § 102): This patent is highly relevant to the dependent claims of US9933866 that focus on distinguishing input types.
  • Claims 5, 6, 11, 12, 18, 19, 20: This patent directly anticipates the concept of distinguishing between "contact by an object other than the stylus with the device" (e.g., "at least one finger") and "a stylus" itself by analyzing signals from the digitizer. It also implicitly covers situations where the object is "at least a part of a human hand" (e.g., a finger). However, it focuses on the detection and processing capabilities of the digitizer system, not on the stylus's specific mechanism of transmitting high-voltage signals to enable this differentiation, which is a key aspect of US9933866's independent claims.

4. US20090095540A1

• Full Citation: US20090095540A1 - N-Trig Ltd. - "Method for palm touch identification in multi-touch digitizing systems"
• Publication/Filing Date: Filed: 2007-10-11, Publication: 2009-04-16
• Brief Description: This patent describes a method for identifying palm touches within a multi-touch digitizing system. The method involves identifying areas of multi-touch input, analyzing the characteristics of at least one of these input areas, and then classifying that area as a palm or another multi-touch input device based on the identified characteristics.
• Potential Anticipation (35 U.S.C. § 102): This patent is highly relevant to the dependent claims of US9933866 related to distinguishing input types.
  • Claims 5, 6, 11, 12, 18, 19, 20: This patent anticipates the method for "distinguishing" contact from "an object other than the stylus" by specifically teaching "palm touch identification." Like US20080238885A1, its abstract focuses on the digitizer's ability to analyze and classify inputs, rather than detailing a stylus's active high-voltage signal transmission to facilitate this distinction.

The obviousness of US Patent 9933866 under 35 U.S.C. § 103 can be analyzed by combining existing prior art references. The patent's priority date is October 28, 2011.

The independent claims (1, 8, and 15) of US9933866 broadly cover an active stylus with one or more electrodes at its tip, logic for wirelessly transmitting signals (including high-voltage signals) to a device's touch sensor, and a component to convert the stylus's normal operating voltage (approximately 1-3 volts) to this higher voltage. Claim 8 further specifies electromagnetic signals and that the high voltage is based on a voltage difference between drive and sense lines of the touch sensor. Claim 15 focuses on the computer-readable storage media embodying the logic for such transmission.

A strong combination of prior art references that would render these claims obvious includes US6377248B1 (Partow), titled "High voltage stylus for portable computer," and US20100315384A1 (Hargreaves), titled "Untethered active pen and a method for communicating with a capacitive sensing device using the untethered active pen." Additionally, US20090095540A1 (N-Trig), which teaches "palm touch identification in multi-touch digitizing systems," provides motivation for certain dependent claims.

Obviousness Analysis for Independent Claims 1, 8, and 15

Primary References: US6377248B1 (Partow) and US20100315384A1 (Hargreaves)

Partow (US6377248B1) teaches a stylus that incorporates high voltage:

• Stylus with electrodes at the tip and high-voltage signals: Partow discloses a stylus (FIG. 1, 100) with a tip (102). The stylus includes a "high voltage power source" (col. 3, lines 6-7) and generates high voltage (e.g., 20V) from a low voltage (e.g., 3V from battery 106) for discharging charge into a touch screen (col. 3, lines 11-15, 20-22). This implies electrodes at the tip to transmit these high-voltage signals. This directly addresses the "high-voltage signals associated with a high voltage comprising a relatively large potential difference compared to a voltage within a voltage range of approximately 1 to approximately 3 volts."
• Component to convert voltage: Partow explicitly describes a "voltage converter 104" (col. 3, lines 16-18) within the stylus that converts the low battery voltage (e.g., 3V) to a high voltage (e.g., 20V).

Hargreaves (US20100315384A1) teaches an active pen with wireless communication to a capacitive touch sensor and control logic:

• Stylus with electrodes at the tip: Hargreaves discloses an "untethered active pen" (abstract, 100) with a nib (102) that includes an electrode (104) (FIG. 1,).
• Computer-readable non-transitory storage media embodying logic for transmitting signals wirelessly to a device through a touch sensor: Hargreaves details a "controller" (208) with "memory" (214) for storing programming that manages the generation and transmission of "modulating signals" wirelessly from the pen's electrode (104) to a "capacitive sensing device" (108) (FIG. 2,-,). This directly covers the aspects of logic, storage media, and wireless transmission to a touch sensor.
• Location identification and synchronization: Hargreaves' active pen communicates with the capacitive sensing device to provide position information. The active signal from the pen can be "synchronized to scan signals of the touch panel" (,).

Motivation to Combine Partow and Hargreaves:
A person having ordinary skill in the art (PHOSITA) would be motivated to combine the high-voltage generation capabilities of Partow's stylus with the advanced active pen communication and control architecture of Hargreaves. The primary motivation would be to enhance the performance of an active stylus for capacitive touchscreens. Using higher voltage signals, as taught by Partow, would lead to stronger, more reliable signals that are easier for a touch sensor to detect and differentiate, thereby improving accuracy, increasing detection range (e.g., for hover detection), and enhancing the signal-to-noise ratio in active stylus systems like that of Hargreaves. This combination would be a predictable application of known elements to achieve a known result in the field of touch input devices.

Application to Independent Claims:

• Claim 1: All elements of Claim 1 are taught or rendered obvious by this combination. Partow provides the high voltage generation and conversion, and the concept of a high-voltage stylus tip interacting with a touch screen. Hargreaves provides the active stylus architecture, the electrodes at the tip, the wireless transmission of signals to a touch sensor, and the computer-readable storage media embodying logic for this process. Combining these, the high-voltage signals would naturally result from the electrodes receiving the high voltage, as taught by Partow.
• Claim 8: This claim specifies "electromagnetic signals" and "the high voltage based on a voltage difference between a drive line of the touch sensor and a sense line of the touch sensor." Capacitive coupling, as described in Hargreaves for stylus-touch sensor interaction, inherently involves electric fields, which are a form of electromagnetic field. A PHOSITA would understand that these "modulating signals" are electromagnetic. Furthermore, Hargreaves teaches that the active pen can be "synchronized to scan signals of the touch panel" (,). It would be obvious to a PHOSITA to use this synchronization (i.e., basing the stylus's high voltage signals on the touch sensor's drive/sense line voltage differences) to optimize the interaction and improve signal detection, especially when employing the high voltage from Partow.
• Claim 15: This claim focuses on the computer-readable non-transitory storage media embodying logic. Hargreaves' controller (208) and memory (214) store and execute programming for generating and transmitting signals (). A PHOSITA would readily implement the control logic for Partow's high voltage generation and transmission within Hargreaves' controller and memory, enabling the transmission of the specified high-voltage electromagnetic signals from the stylus's tip electrodes.

Obviousness Analysis for Dependent Claims

• Claim 2 & 16 (Component is a transformer): The patent itself notes a transformer as an example of a component for producing high voltage (). Transformers are well-known in the art for voltage conversion. A PHOSITA would obviously select a transformer as the "voltage converter" taught by Partow (104).
• Claim 3 & 10 (High voltage 10-20 volts): Partow explicitly teaches converting a 3V battery voltage to "a high voltage (e.g. 20V)" (col. 3, lines 20-22). This falls within the claimed range of approximately 10 to approximately 20 volts.
• Claim 4 (High-voltage signals identify location): Both Partow's "position responsive apparatus" and Hargreaves' pen communicating with a capacitive sensing device for position inherently teach identifying the stylus's location. Utilizing high-voltage signals from Partow in Hargreaves' system would enhance this known functionality.
• Claim 5, 11, 18 (Simulate or distinguish contact): US20090095540A1 (N-Trig) explicitly addresses the problem of "palm touch identification in multi-touch digitizing systems" (abstract). This demonstrates a clear motivation in the prior art to distinguish between different types of contact (e.g., stylus vs. finger/palm). A PHOSITA, combining Partow's high voltage stylus with Hargreaves' active communication, and aware of the problem taught by N-Trig, would be motivated to use the distinctive high-voltage signals to actively simulate or differentiate stylus contact from other objects (like a human hand) on the touch sensor. This is a predictable application of known technology to solve a known problem.
• Claim 6 & 12 (Object is part of a human hand): N-Trig directly teaches distinguishing "palm touch" or "finger" contact from a stylus, where the "palm" is part of a human hand.
• Claim 7 (High-voltage signals based on voltage used by touch sensor): As noted for Claim 8, Hargreaves teaches synchronization with the touch panel's scan signals (,). Basing the stylus's transmitted signals, including high-voltage signals, on the touch sensor's operating voltages would be an obvious engineering choice to ensure proper interaction and detection.
• Claim 13, 14, 19, 20 (High voltage same/opposite polarity as voltage difference between drive/sense lines): Hargreaves teaches the pen generates "modulating signals" that can be "synchronized to scan signals of the touch panel" (,). The claimed patent itself describes using signals with positive (Vhigh+) or negative (Vhigh-) polarity to differentiate contact (-). Given the motivation to distinguish contacts (from N-Trig), a PHOSITA would find it obvious to apply the high voltage (from Partow) with either the same or opposite polarity relative to the touch sensor's drive/sense line voltage differences as an engineering design choice to achieve specific interaction effects (e.g., simulating a "finger down" or "lifting off" event, or actively canceling out palm capacitance).