Prior art — US Patent 9729693

Prior Art Analysis for US Patent 9,729,693

The following is an analysis of prior art cited during the prosecution of US patent 9,729,693. The priority date for the '693 patent is June 7, 2016. All references listed were published or filed before this date and thus constitute valid prior art. The analysis focuses on potential anticipation of the independent claims (1, 11, and 16) which describe a multi-stage method for determining if a wearable device is being worn by a user.

1. US 2015/0265217 A1 (Cited by Examiner)

Full Citation: US Patent Application Publication No. 2015/0265217 A1. "Confidence indicator for physiological measurements using a wearable sensor platform."
Assignee: Samsung Electronics Co., Ltd.
Dates: Filed March 24, 2014; Published September 24, 2015.
Description: This application describes a wearable device that measures physiological signals like photoplethysmogram (PPG) and provides a "confidence indicator" for the measurement. The confidence level is determined by analyzing the quality of the signal, which can be affected by factors like user motion (measured by an accelerometer) and the signal-to-noise ratio. The system can then decide whether to display the physiological data based on this confidence level.
Potential Anticipation of Claims 1, 11, 16:
- This reference is highly relevant as it explicitly discloses calculating a confidence metric for sensor data from a wearable device. It clearly teaches the concepts corresponding to elements (c) (calculating a signal quality metric) and (d) (determining that the signal quality metric is greater than a measurement threshold) of the '693 patent's claims.
- However, the reference does not appear to disclose the specific two-step voltage check used to determine if the device is worn before calculating the signal quality metric. It does not teach measuring a first voltage with a light emitter off (element a) and a second voltage with the emitter on (element b) as a prerequisite for determining the "worn" status. Its confidence metric is more focused on the quality of the physiological signal itself (e.g., during motion) rather than a pre-screening "worn/not worn" test based on ambient light and skin contact. Therefore, it likely does not anticipate all elements of the claims in a single teaching.

2. US 2014/0247151 A1 (Cited by Examiner)

Full Citation: US Patent Application Publication No. 2014/0247151 A1. "System or device with wearable devices having one or more sensors with assignment of a wearable device user identifier to a wearable device user."
Assignee: Hello Inc.
Dates: Filed March 4, 2013; Published September 4, 2014.
Description: This application details a system including wearable sensors that monitor a user's sleep and environment. The disclosure discusses determining when a user is wearing the device, for instance, by detecting a characteristic temperature change or motion patterns consistent with being worn. This allows the system to associate sensor data with a specific user and condition.
Potential Anticipation of Claims 1, 11, 16:
- This reference teaches the broad concept of determining that a device is worn by a user (element e). However, the method it discloses for making this determination relies on different inputs, such as temperature sensors or motion analysis, rather than the specific three-part test claimed in the '693 patent.
- It does not disclose the sequence of checking a voltage with a light emitter off (element a), checking a voltage with the emitter on (element b), and then calculating a signal quality metric from a sensor like a pulse oximeter (element c) to confirm the "worn" status. It therefore fails to anticipate the key limitations of the independent claims.

3. US 8,920,332 B2 (Fitbit)

Full Citation: US Patent No. 8,920,332 B2. "Wearable heart rate monitor."
Assignee: Fitbit, Inc.
Dates: Filed June 24, 2013 (claiming priority to June 22, 2012); Issued December 30, 2014.
Description: This patent describes a wearable fitness monitoring device with a photoplethysmographic (PPG) sensor for measuring heart rate. It discusses improving signal quality by adjusting the sensor's operation (e.g., light source intensity) based on factors like user motion and detected skin characteristics. The goal is to obtain a reliable heart rate reading despite challenges like motion artifacts.
Potential Anticipation of Claims 1, 11, 16:
- This patent is relevant as it deals with data and signal quality from a wearable PPG sensor. It implies the need for good skin contact to get a reliable signal, which relates to the '693 patent's goal. It discusses analyzing the sensor output to determine characteristics of the user.
- However, it does not explicitly teach the sequential, three-stage method for confirming the device is worn. There is no disclosure of a specific test where a first voltage is measured with the light emitter off to rule out bright light, followed by a second voltage measurement with the emitter on to confirm skin-like reflection, followed by a signal quality metric calculation for the final "worn" determination. Its focus is on optimizing the quality of a heart rate measurement, assuming the device is already worn.

4. US 9,167,995 B2 (Cercacor)

Full Citation: US Patent No. 9,167,995 B2. "Physiological parameter confidence measure."
Assignee: Cercacor Laboratories, Inc.
Dates: Filed March 1, 2005; Issued October 27, 2015.
Description: This patent describes a method for generating a confidence metric associated with a physiological measurement from a noninvasive optical sensor (e.g., a pulse oximeter). The confidence is determined by analyzing various aspects of the measured signal, such as its stability, the presence of artifacts, and comparison to expected signal shapes or values. This helps a user or clinician gauge the reliability of the reading.
Potential Anticipation of Claims 1, 11, 16:
- Similar to the Samsung reference ('217), this patent strongly teaches the concepts of calculating a signal quality or confidence metric (element c) and comparing it to a threshold (element d).
- However, its purpose is to validate a physiological measurement (like blood oxygen saturation) rather than to determine a simple "worn/not worn" status. It does not describe the specific pre-screening steps of measuring voltages with a light emitter in off and on states (elements a and b) to first ensure the device is properly positioned on a user before taking a measurement. It is therefore unlikely to anticipate the full claimed method.

5. US 7,367,949 B2

Full Citation: US Patent No. 7,367,949 B2. "Method and apparatus based on combination of physiological parameters for assessment of analgesia during anesthesia or sedation."
Assignee: Instrumentarium Corp.
Dates: Filed July 7, 2003; Issued May 6, 2008.
Description: This patent discloses a system for use in a clinical setting to assess a patient's level of analgesia (pain relief). It combines multiple physiological parameters, such as heart rate, blood pressure, and pulse wave amplitude, to create a composite index. The system analyzes the quality of the input signals to ensure the index is reliable.
Potential Anticipation of Claims 1, 11, 16:
- This patent discusses assessing the quality of physiological signals, which has a thematic overlap with the '693 patent.
- However, the context (clinical anesthesia monitoring) and the method are entirely different. The patent is not concerned with a consumer wearable device or the specific problem of determining if it is being worn versus, for example, sitting on a table. It does not disclose the two-stage voltage check or the use of a signal quality metric for a "worn" status determination. It is not relevant prior art for anticipation.

6. US 2017/0095182 A1 (Cited by Examiner)

Full Citation: US Patent Application Publication No. 2017/0095182 A1. "Rh incompatibility detection."
Assignee: Hewlett-Packard Development Company, L.P.
Dates: Filed June 17, 2014; Published April 6, 2017.
Description: This application describes a non-invasive method for detecting Rh incompatibility in a fetus by analyzing light passed through a pregnant person's finger or earlobe. While its medical purpose is specific, the underlying technology involves using optical sensors and analyzing the resulting signal.
Potential Anticipation of Claims 1, 11, 16:
- The examiner likely cited this reference for its general teachings on using optical sensors for physiological measurements. It inherently involves placing a sensor on a person and getting a signal.
- However, the reference is directed at a very specific diagnostic purpose and does not address the general problem of confirming a wearable device is properly worn. It does not disclose any method resembling the claimed sequence of checks (light emitter off, light emitter on, signal quality metric) to determine a "worn" status. This reference does not anticipate the claims.