Obviousness

Based on the information provided within US Patent 10,874,304, particularly its descriptions of existing techniques and challenges, and considering a priority date of December 31, 2012, a person having ordinary skill in the art (PHOSITA) would have been motivated to combine known elements to arrive at the claimed inventions. The patent itself outlines the landscape of prior art and problems, thereby revealing motivations for the claimed improvements.

The core of the independent claims (1, 9, 14, 19, 23, 27, and 33) revolves around a wearable device or measurement system that uses near-infrared (NIR) semiconductor light sources (e.g., LEDs) for non-invasive physiological measurements, with a focus on improving the signal-to-noise ratio (SNR) and integrating with modern communication technologies.

Elements of Prior Art / General Knowledge (as described in US 10,874,304):

1. Near-infrared (NIR) Spectroscopy for Physiological Measurements: The patent acknowledges that "near-infrared spectroscopy such as absorption spectroscopy or near-infrared diffuse reflection or transmission spectroscopy" was a known method for investigating materials, including for non-invasive procedures on blood constituents. [cite: "near-infrared spectroscopy such as absorption spectroscopy or near-infrared diffuse reflection or transmission spectroscopy.", "the non-invasive procedures have often transmitted or reflected light through the skin, but skin has many spectral artifacts in the near-infrared that may mask the glucose signatures."] The patent also mentions that "SWIR light may be generated by light sources such as lamps, light emitting diodes, one or more laser diodes, super-luminescent laser diodes, and fiber-based super-continuum sources." [cite: "SWIR light may be generated by light sources such as lamps, light emitting diodes, one or more laser diodes, super-luminescent laser diodes, and fiber-based super-continuum sources."]
2. Semiconductor Light Sources (LEDs): Light Emitting Diodes (LEDs) were known as suitable light sources, particularly in the SWIR wavelength range, offering "higher power level...and with higher energy efficiency" compared to lamps, and being "solid state components that emit a wavelength band that is of moderate width." [cite: "LED's can be used that have a higher power level in the SWIR wavelength range.", "LED's also produce an incoherent beam, but the power level can be higher than a lamp and with higher energy efficiency.", "LED's are solid state components that emit a wavelength band that is of moderate width, typically between about 20 nm to 40 nm."] The patent also notes that "the LED output may more easily be modulated, and the LED provides the option of continuous wave or pulsed mode of operation." [cite: "Also, the LED output may more easily be modulated, and the LED provides the option of continuous wave or pulsed mode of operation."]
3. Improving SNR by Increasing Light Intensity: The patent explicitly states that "a higher light level or intensity may improve the signal-to-noise ratio for the measurement." [cite: "the selection of the constituent of interest may be improved using a number of techniques. For example, a higher light level or intensity may improve the signal-to-noise ratio for the measurement."] This is a fundamental principle in optical sensing.
4. Differential Measurements for Noise Reduction: The patent describes a technique for performing a "differential measurement" by placing one probe over a vein-rich region and a second probe over a region without distinct veins, and then "subtracting" the outputs to "at least partially cancel out the features from the skin." [cite: "a near-infrared diffuse reflectance measurement may be performed by placing one probe 603 above the vein-rich region 601 . To turn this into a differential measurement, a second probe 604 may be placed above a region without distinct veins 602 .", "the outputs from the two probes may be subtracted 605 to at least partially cancel out the features from the skin.", "the differential measurements may be intended to compensate for or subtract out (at least in part) the interference from the skin."] This illustrates the known concept of using spatially separated detectors for background or common-mode noise subtraction.
5. Ambient Light Subtraction: While presented as part of the invention, the concept of "capturing light while the LEDs are off and convert the captured light into a first signal, and to capture light while at least one of the LEDs is on and convert the captured light into a second signal... by differencing the first signal and the second signal" is a common and well-known method for removing ambient light interference in optical sensing.
6. Modulation and Lock-in Techniques: The patent describes that the receiver is configured to be "synchronized to the modulation of the at least one of the LEDs," and to use a "lock-in technique that detects the modulation frequency." These are standard, effective techniques for extracting weak signals from noisy backgrounds.
7. Wearable Devices and Smartphone/Remote Connectivity: The patent discusses "a wearable device" and "a measurement system... with a smart phone or tablet, and a remote device." [cite: "a wearable device includes a measurement device including a light source comprising a plurality of light emitting diodes (LEDs) for measuring one or more physiological parameters", "a measurement system is provided with a light source, an apparatus, a receiver, a smart phone or tablet, and a remote device."] By 2012, wearable physiological monitors and their integration with smartphones for data display, storage, and cloud-based communication were well-established trends in health technology. [cite: "schematically shows that the medical measurement device can be part of a personal or body area network that communicates with another device (e.g., smart phone or tablet) that communicates with the cloud."]
8. Analog-to-Digital Converters (ADCs) and Digital Signal Processing: The patent refers to "one or more analog to digital converters coupled to the spatially separated detectors." [cite: "the receiver may also be coupled to analog to digital converters, particularly if the signal is to be fed to a digital device."] The use of ADCs to digitize sensor outputs for further processing (e.g., "Fourier transform and mathematical manipulation") was standard practice. [cite: "the output signal is generated at least in part by using a Fourier transform and mathematical manipulation of a signal resulting from the captured light."]

Obviousness Combinations and Motivation:

A PHOSITA, seeking to improve the accuracy and usability of non-invasive NIR physiological measurements in wearable devices (a known application), would have found it obvious to combine the aforementioned prior art elements.

Scenario 1: Combination for Claims 1, 9, 14 (SNR improvement via intensity and differential measurement)

• Starting Point: A known wearable device employing NIR LEDs for physiological measurements (e.g., a basic pulse oximeter adapted for the wrist or ear).
• Motivation to Increase Light Intensity: Faced with low signal levels or poor SNR, the PHOSITA would be directly motivated by the explicit knowledge that "a higher light level or intensity may improve the signal-to-noise ratio." [cite: "the selection of the constituent of interest may be improved using a number of techniques. For example, a higher light level or intensity may improve the signal-to-noise ratio for the measurement."] This is a fundamental and predictable engineering solution.
• Motivation for Spatially Separated Detectors and Comparing Outputs (Differential Measurement): To address interfering signals, such as skin artifacts or motion noise, the PHOSITA would be motivated to apply known differential measurement techniques. The patent itself illustrates this by describing probes over vein-rich and non-vein regions with signal subtraction to cancel skin features. [cite: "a near-infrared diffuse reflectance measurement may be performed by placing one probe 603 above the vein-rich region 601 . To turn this into a differential measurement, a second probe 604 may be placed above a region without distinct veins 602 .", "the outputs from the two probes may be subtracted 605 to at least partially cancel out the features from the skin.", "the differential measurements may be intended to compensate for or subtract out (at least in part) the interference from the skin."] Extending this concept to use multiple spatially separated detectors in a wearable device, and comparing their outputs, for common-mode rejection, would be a logical and predictable step for a skilled artisan.
• Motivation for Modulation and Lock-in (Claims 9, 14): When dealing with weak optical signals immersed in noise (including ambient light), modulating the LED source and employing a synchronous detection method like a lock-in amplifier is a well-established and highly effective technique to isolate the signal of interest. The patent identifies this as a feature of the receiver.

Scenario 2: Combination for Claims 19, 23, 33 (SNR improvement via ambient light subtraction and intensity increase)

• Starting Point: A known wearable device employing NIR LEDs for physiological measurements.
• Motivation for Ambient Light Subtraction (LEDs off vs. on): A significant challenge for wearable optical devices is ambient light interference. A PHOSITA would be motivated to implement a known solution for ambient light rejection, such as taking a reading with the LEDs off (background) and subtracting it from a reading with the LEDs on (signal + background). This "differencing the first signal and the second signal" is a routine design choice for optical sensors to improve SNR.
• Motivation to Increase Light Intensity: As in Scenario 1, increasing light intensity is a direct and known method to improve SNR.
• Motivation for Spatially Separated Detectors and Comparing Outputs (Claims 19, 23): As in Scenario 1, this provides a known mechanism for further noise and interference reduction.

Scenario 3: Combination for Claim 27 (Measurement system with remote connectivity)

• Starting Point: A known measurement system utilizing semiconductor sources for optical analysis of a sample, providing an output signal, with a receiver synchronized to the light source.
• Motivation to Increase Light Intensity for SNR: The same fundamental motivation applies as above.
• Motivation for Smartphone/Tablet and Remote Device Integration: The widespread adoption of smartphones and tablets for data collection, display, and communication, along with the growth of cloud-based health monitoring systems, would have made it obvious for a PHOSITA to integrate a physiological measurement device with these technologies. The patent explicitly illustrates this architecture. [cite: "schematically shows that the medical measurement device can be part of a personal or body area network that communicates with another device (e.g., smart phone or tablet) that communicates with the cloud."] The benefits of data storage, visualization, historical tracking, and remote consultation are clear and would drive such integration.

Overall Conclusion on Obviousness:

The independent claims of US 10,874,304 appear to describe a combination of elements and techniques that were individually known in the art prior to the patent's priority date of December 31, 2012. The motivations for combining these elements—specifically to improve signal-to-noise ratio in non-invasive physiological measurements, mitigate interference (e.g., from skin or ambient light), and enhance usability through wearable design and connectivity—are explicitly recognized problems and solutions within the patent's own description of the field. A PHOSITA, seeking to overcome these known problems, would have found these combinations to be predictable and obvious applications of existing technological principles and routine engineering choices.