SpO2 Optical Detection Timing for Photocurrent Separation

The patent applies periodic action by using time-division multiplexing to alternately activate different light sources (e.g., red and infrared LEDs) in periodic cycles. Each light source is activated for a specific duration within a cycle, allowing the photodetector to measure photocurrents sequentially rather than simultaneously. This periodic activation prevents photocurrent overlap while maintaining the capability to measure multiple wavelengths, thereby resolving the contradiction between measurement capability and detection accuracy.

The patent segments the measurement process into distinct time intervals, with each interval dedicated to a specific light source wavelength. By dividing the measurement cycle into separate segments for different wavelengths and measuring photocurrents in each segment independently, the system avoids mixing of photocurrent signals. This segmentation approach enables accurate distinction between different wavelength contributions while preserving multi-wavelength measurement functionality.

Instead of continuous lighting, the patent implements periodic lighting where each light source is activated in alternating cycles with controlled duty cycles. This periodic action maintains adequate signal strength during active periods while ensuring complete temporal separation between different light sources, preventing photocurrent overlap and enabling accurate distinction between different wavelength signals.

The patent employs dynamic control of light source activation and readout timing, adjusting the timing and duration of light emission and corresponding photocurrent measurement windows. This dynamic approach optimizes the balance between signal acquisition time and temporal separation, ensuring sufficient signal strength while maintaining clear distinction between photocurrents from different light sources through adaptive timing control.