Photodetector Cell Segmentation for Ambient Light Noise Reduction
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Solution Overview
Problem
Distance measuring devices face challenges in accurately detecting measurement light outdoors due to ambient light interference, requiring repeated mechanical adjustments to align the light receiving region with the incidence region of measurement light.
Innovation Solution
A photodetector system that selects specific light receiving elements with adjustable light receiving regions to coincide with the incidence region of measurement light, using a combination of light receiving elements, resistors, and selectors to minimize ambient light interference, allowing for precise detection of measurement light even in the presence of ambient illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical adjustment is performed to make the light receiving region exactly match the incidence region of measurement light, then measurement precision is improved, but adjustment time increases significantly due to repeated mechanical fine adjustments
Solution Approach 1:
The photodetector is divided into multiple independent light receiving elements (first through fourth elements) with distinct light receiving regions. This segmentation allows selective activation of specific elements based on measurement conditions, eliminating the need for repeated mechanical adjustments to achieve proper alignment.
Solution Approach 2:
The patent implements dynamic selection of light receiving elements through control circuitry that can activate different elements based on real-time measurement requirements. This dynamic switching capability replaces static mechanical adjustment mechanisms, enabling rapid adaptation without time-consuming manual intervention.
2Measurement precision
If the light receiving region is made larger to capture more measurement light, then detection sensitivity is improved, but ambient light interference increases
Solution Approach 1:
Different light receiving elements are assigned to detect different spatial regions (e.g., first and second elements for one direction, third and fourth for another direction). This local specialization allows the system to capture sufficient measurement light from specific angles while inherently rejecting ambient light from other directions, achieving both sensitivity and noise reduction.
Solution Approach 2:
By segmenting the photodetector into multiple elements with specific geometric arrangements, the system can selectively receive light from desired directions while blocking or ignoring light from unwanted directions. This spatial segmentation provides passive optical filtering without requiring additional active components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system enables accurate detection of measurement light by aligning the light receiving region with the incidence region, reducing ambient light noise and streamlining the optical adjustment process, thus improving the reliability and efficiency of distance measurements.
Implementation Method 1
the reflected measurement light is detected as a photon
Data Source
AI summary
A photodetector includes a plurality of cells each configured to detect light and including: a light receiving element configured to output an electrical signal upon receipt of the light, a resistor connected to the light receiving element, and first and second switches connected to the resister. Either the first switch or the second switch is turned on according to a selection signal. The photodetector further includes a first output terminal connected to the first switch of each of the cells and through which a first output signal is output based on the electrical signal that has been output from the first switch, and a second output terminal connected to the second switch of each of the cells and through which a second output signal is output based on the electrical signal that has been output from the second switch.