Obviousness

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).