Position Detection Sensor with Asymmetric Pixel Groups for Multi-Beam Ambiguity
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Solution Overview
Problem
Existing position detection sensors face challenges in accurately detecting the incident position of multiple light beams with the same luminance, as their projection images in two directions can become identical, leading to ambiguity in calculating the two-dimensional positions.
Innovation Solution
A position detection sensor is designed with a first pixel pair group and a second pixel pair group, each generating electric signals based on incident light amounts, where the calculation unit performs center-of-gravity operations and weighting on these signals to accurately determine the incident positions, even when multiple light beams with the same luminance are incident.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional light detection device with two-dimensional pixel arrangement is used, then the device structure is simple and manufacturing is easy, but it cannot accurately detect incident positions of multiple light beams with the same luminance due to identical projection images
Solution Approach 1:
The pixel array is segmented into four distinct pixel groups (first, second, third, and fourth pixel groups) arranged in a specific pattern. Each pixel group detects light incident from a different directional region, allowing the system to distinguish between multiple light beams by comparing their relative positions across the four groups, thereby resolving the ambiguity of identical projection images.
Solution Approach 2:
The four pixel groups are arranged asymmetrically with respect to the light incident surface, creating distinct detection zones for different incident directions. This asymmetric arrangement ensures that light beams incident from different positions produce different intensity distributions across the pixel groups, enabling accurate position detection even when luminance is identical.
2Adaptability or versatility
If multiple light beams with the same luminance are detected simultaneously, then the detection coverage is improved, but the projection images become identical making position calculation ambiguous
Solution Approach 1:
The calculation unit acts as an intermediary that processes the intensity signals from the four pixel groups. It computes the incident position by analyzing the relative intensity distribution across the pixel groups, effectively decoding the position information that would otherwise be lost due to identical projection images of multiple light beams.
Solution Approach 2:
The invention transitions from two-dimensional projection image analysis to three-dimensional spatial reasoning by utilizing the intensity distribution across four spatially separated pixel groups. This additional spatial dimension allows the system to disambiguate between multiple light beams by comparing their relative positions in the detection space.
3Measurement precision
If pixel parts are arranged to differentiate incident positions, then detection accuracy is improved, but the device structure becomes more complex
Solution Approach 1:
Each pixel group serves multiple functions: it detects light intensity, provides spatial reference information, and contributes to the overall position calculation. This multi-functionality reduces the need for additional specialized components, simplifying the manufacturing process while maintaining high detection accuracy.
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
This configuration allows for precise detection of the incident positions of each light beam by differentiating between the signals based on intensity variations, effectively resolving the ambiguity in projection images.
Implementation Method 1
a first pixel part that generates a first electric signal corresponding to an incident light amount of the light and a second pixel part that is disposed side by side with the first pixel part in the first direction and generates a second electric signal corresponding to an incident light amount of the light
Data Source
AI summary
In a first pixel part, as an incident position is closer to a first end of a first pixel pair group in a second direction, an intensity of a first electric signal decreases. In a second pixel part, as the incident position is closer to the first end, an intensity of a second electric signal increases. In a third pixel part, as the incident position is closer to a second end of a second pixel pair group in a first direction, an intensity of a third electric signal decreases. In a fourth pixel part, as the incident position is closer to the second end, an intensity of a fourth electric signal increases. A calculation unit performs weighting on a first position on the basis of the third and fourth electric signals, and performs weighting on a second position on the basis of the first and second electric signals.