Dual-Receiver Proximity Sensor Layout for Crosstalk-Controlled Range Sensing
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Solution Overview
Problem
Conventional proximity sensors are ineffective in performing both near proximity sensing (0˜5 cm) and far proximity sensing (3˜60 cm).
Innovation Solution
A proximity sensor design featuring a light emitter and two light receivers with distinct crosstalk characteristics, along with light shielding walls, to optimize detection regions and reduce crosstalk, allowing for effective near and far proximity sensing using a VCSEL light emitter and time-of-flight method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single light receiver is used in conventional proximity sensors, then the device structure is simple, but the sensor cannot effectively perform both near proximity sensing (0-5 cm) and far proximity sensing (3-60 cm)
Solution Approach 1:
The sensor divides the detection function into two separate light receivers: a first light receiver for near proximity sensing (0-5 cm) and a second light receiver for far proximity sensing (3-60 cm). Each receiver is optimized for its specific detection range, allowing the sensor to perform both near and far sensing effectively without excessive complexity
Solution Approach 2:
The patent positions the two light receivers at different distances from the transmissive window along the optical axis. The first light receiver is positioned closer to the window while the second light receiver is positioned farther away, creating a spatial dimension differentiation that enables multi-range detection capability
2Measurement precision
If light receivers are positioned closer to the transmissive window for better near sensing, then near proximity detection is improved, but internal reflected light and leaked light cause crosstalk and reduce far proximity sensing accuracy
Solution Approach 1:
The patent extracts and removes harmful internal reflected light and leaked light from the optical path by introducing light shielding walls. These shielding structures block the harmful light before it reaches the light receivers, preventing crosstalk and maintaining detection accuracy for both near and far proximity sensing
Solution Approach 2:
Light shielding walls are introduced as intermediary elements between the transmissive window and the light receivers. These walls act as mediators that selectively block harmful internal reflected light and leaked light while allowing external reflected light from targets to reach the light receivers, thus resolving the crosstalk issue
3Measurement precision
If light shielding walls are added to reduce crosstalk, then far proximity sensing accuracy is improved, but the device structure becomes more complex
Solution Approach 1:
The light shielding walls are strategically positioned only in specific locations where internal reflected light and leaked light propagate. Rather than enclosing the entire sensor, the shielding walls are placed locally at critical points in the optical path, providing effective crosstalk reduction while minimizing overall structural complexity
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
Enables accurate and efficient detection of targets within both near and far proximity ranges by minimizing crosstalk and optimizing the distance and placement of light receivers, enhancing the precision and reliability of proximity sensing.
Implementation Method 1
the light emitter is a vertical cavity surface emitting LASER (VCSEL)
Implementation Method 2
the proximity sensor detects whether a target to be inspected exists within the second detection region by time-of-flight (TOF) method
Data Source
AI summary
The present disclosure relates to a proximity sensor. The proximity sensor includes: a light emitter (for example, a vertical cavity surface emitting LASER (VCSEL)) configured to irradiate light to a target to be inspected; a first light receiver having a first crosstalk characteristic, configured to detect an external reflected light from a target to be inspected within a first detection region (for example, 0˜5 cm approximately); and a second light receiver having a second crosstalk characteristic different from the first crosstalk characteristic, configured to detect an external reflected light from a target to be inspected within a second detection region (for example, 3˜60 cm approximately) relatively further than the first detection region.