SiPM Pixel Array Signal Rearrangement for LIDAR Noise Reduction
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Solution Overview
Problem
Conventional LIDAR systems using Silicon Photo Multiplier (SiPM) face challenges in achieving high-performance due to noise from ambient light and accurate synchronization, particularly in in-vehicle applications.
Innovation Solution
A light receiving device with a switch circuitry that rearranges signals from pixels based on their relative positions, allowing for separate output of signals from each pixel and improved signal-to-noise ratio (SNR) by eliminating noise from non-irradiated pixels, and enabling robustness against positional misalignment and varying light intensities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional SiPM sensor methods are used for LIDAR, then the system can detect light signals, but noise from ambient light and synchronization issues deteriorate measurement precision
Solution Approach 1:
The patent divides the sensor array into multiple independently controllable pixel regions. By segmenting the light receiving area into discrete pixels with individual control, the system can selectively activate only the pixels that should receive light signals, thereby eliminating noise from pixels that are not supposed to be active. This segmentation approach directly addresses the ambient light noise problem by enabling precise spatial control over which pixels contribute to the measurement.
Solution Approach 2:
The patent implements dynamic control of pixel activation states through voltage application. Pixels can be switched between active and inactive states based on real-time requirements, allowing the system to adapt to varying light conditions and measurement needs. This dynamic control enables the system to minimize noise by deactivating pixels that would otherwise pick up ambient light, while maintaining sensitivity in pixels that need to detect actual signals.
2Area of stationary object
If all pixels in the sensor array are activated, then the light receiving area is maximized, but signals from non-irradiated pixels increase noise and reduce signal-to-noise ratio
Solution Approach 1:
The patent applies local quality control by assigning different operational states to different regions of the sensor array. Instead of uniform activation across all pixels, the system selectively activates only those pixels located in regions where light signals are expected. This local differentiation allows the system to maintain a large effective light receiving area while ensuring that only pixels in appropriate positions contribute to the signal, thereby preserving high signal-to-noise ratio.
3Device complexity
If the light receiving position is fixed, then the system structure is simplified, but the system becomes sensitive to positional misalignment and varying light intensities
Solution Approach 1:
The patent introduces dynamic reconfigurability to the sensor system, allowing the light receiving position to be adjusted electronically by changing which pixels are activated. This dynamic capability enables the system to adapt to positional misalignment and varying light intensities without requiring complex mechanical adjustment mechanisms. The flexibility to reconfigure the active pixel pattern provides robustness against alignment issues while maintaining relatively simple system structure.
4Measurement precision
If conventional synchronization methods are used, then the sensor can operate with laser light emission, but accurate synchronization is difficult to achieve and reduces measurement accuracy
Solution Approach 1:
The patent implements preliminary control by pre-configuring which pixels should be active before light signals are emitted. By establishing the correct pixel activation pattern in advance, corresponding to the expected light receiving positions, the system ensures that only appropriately positioned pixels are sensitive to incoming signals. This preliminary action simplifies synchronization requirements because the system is already prepared to detect signals from the correct spatial locations without requiring complex real-time synchronization adjustments.
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 solution enhances the accuracy of light reception and distance measurement in LIDAR systems by improving SNR and allowing for accurate detection even with non-coaxial optical systems and misaligned light receiving positions, enabling longer range and higher resolution measurements.
Implementation Method 1
senses the intensities of the light reflected from the measurement target with a sensor, and converts the intensities into time-series digital signals
Data Source
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AI summary
A light receiving device (1) includes a light receiver (10) including pixels (12) and a light receiving area (16). The pixels (12) are arranged in an array in a first direction and in a second direction intersecting with the first direction and each of the pixels (12) has one light receiving element (14) or more. The light receiving area (16) has continuous pixels out of the pixels (12), outputs signals based on intensities of light received in the continuous pixels, and is changed in position in the light receiver (10) according to a signal indicating a position in the first direction and a position in the second direction.