SPAD Pixel Array with Variable Bandpass Filters for Dynamic Range

The patent applies local quality by placing optical band pass filters with different full width at half maximum (FWHM) values at different pixel locations. Specifically, some pixels are equipped with first optical band pass filters having a first FWHM, while other pixels have second optical band pass filters with a second FWHM that is narrower than the first. This allows different regions of the pixel array to have different sensitivity characteristics, thereby achieving a wide dynamic range without requiring different physical structures for the SPADs themselves.

The patent utilizes parameter changes by varying the optical properties (full width at half maximum) of the band pass filters rather than changing the physical structure of the SPADs. By adjusting the FWHM parameter of the optical filters, the system achieves different sensitivity levels for different pixels, which expands the dynamic range while maintaining uniform SPAD manufacturing processes and reducing characteristic variation.

The patent introduces optical band pass filters as intermediary components between the incident light and the SPADs. These filters serve as mediators that modify the light spectrum before it reaches the SPAD photodetectors. By using filters with different FWHM values, the system achieves different effective sensitivities for different pixels without altering the SPAD physical structures, thereby maintaining manufacturing precision and characteristic consistency.

The patent changes the optical parameter (full width at half maximum) of the band pass filters to achieve different sensitivities rather than changing the physical parameters of the SPADs. This approach allows the system to obtain a range of sensitivity values while keeping the SPAD manufacturing process uniform, thus maintaining high manufacturing precision and characteristic consistency across all pixels.

The patent segments the pixel array into different types of pixels based on their optical filter characteristics. Some pixels are equipped with first optical band pass filters having a wider FWHM to capture more signal intensity, while other pixels have second optical band pass filters with a narrower FWHM to achieve lower sensitivity for distant object detection. This segmentation allows the system to handle both strong and weak signals effectively, expanding the dynamic range without significantly compromising overall signal detection capability.

The patent applies local quality by assigning different FWHM values to optical filters at different pixel locations based on their intended function. Pixels with wider FWHM filters are positioned to detect stronger signals from nearby objects, while pixels with narrower FWHM filters are used for detecting weaker signals from distant objects. This localized optimization of filter characteristics allows the system to maintain adequate signal intensity for each pixel's specific detection task while achieving a wide overall dynamic range.