Optical Shielding Device for Sensor Unit Crosstalk Reduction
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Solution Overview
Problem
Optical crosstalk between closely spaced reference and measurement radiation receivers in distance measuring devices reduces measurement accuracy, as existing technologies fail to provide effective optical isolation.
Innovation Solution
A sensor unit with an optical shielding device that optically separates detection areas for reference and measurement radiation using permeable recesses and components, ensuring precise positioning and minimal crosstalk, even when receivers are integrated on a single silicon chip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If receivers for reference and measurement radiation are arranged close to one another to save space and reduce costs, then device integration and productivity are improved, but optical crosstalk increases and measurement precision deteriorates
Solution Approach 1:
The sensor element is divided into multiple separate detection areas (first detection area for measurement radiation, second detection area for reference radiation) that are spatially segmented on the sensor surface. This segmentation allows each detection area to be optimized for its specific function while maintaining close proximity for integration purposes.
Solution Approach 2:
An optical shielding device is introduced as an intermediary element positioned between the first and second detection areas. This shielding device with its specific recess structure acts as a mediator that allows measurement radiation to reach the first detection area while blocking reference radiation from reaching the same area, thereby preventing crosstalk despite the close arrangement of receivers.
2Device complexity
If receivers for reference and measurement radiation are arranged close to one another, then device complexity is reduced, but optical crosstalk intensifies and measurement precision worsens
Solution Approach 1:
The optical shielding device is designed with different local properties: it has a first recess that is open or permeable to allow measurement radiation to reach the first detection area, and a second recess that is closed or opaque to block reference radiation from reaching the first detection area. This local differentiation of optical properties enables precise control of radiation paths in a compact arrangement.
Solution Approach 2:
The optical shielding device serves as an intermediary structure that mediates between the closely arranged receivers. By positioning this shielding element with its specific recess pattern between the detection areas, it enables close receiver arrangement while maintaining optical isolation through its selective radiation blocking and transmitting properties.
3Measurement precision
If an optical shielding device is introduced to separate detection areas, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The optical shielding device is merged with the sensor element structure, where the shielding device is positioned in direct contact with or integrated into the sensor element housing. The recesses in the shielding device are precisely aligned with the detection areas, combining the shielding function with the sensor element's structural design rather than adding completely separate components.
Solution Approach 2:
The optical shielding device performs multiple functions: it provides optical isolation between detection areas, structurally supports the close arrangement of receivers, and its recess pattern is specifically designed to match the detection area configuration. This multi-functionality reduces the need for additional separate components despite the improved measurement precision.
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 measurement accuracy by ensuring effective optical isolation between reference and measurement radiation, reducing crosstalk and maintaining high precision despite small distances between detectors, while also saving production costs and accommodating tight manufacturing tolerances.
Implementation Method 1
The optical shielding device is positioned and fixed with respect to the sensor element and optically separates the first and second detection areas from each other. The optical shielding device also has a first recess and a second recess, which are permeable to the optical radiation of a first wavelength range.
Data Source
Figure 1
Figure 2A~3A
Figure 3B~4B
AI summary
The invention relates to a sensor unit (33) for detecting reference and measurement radiation (7, 5) for a distance measurement device. The sensor unit (33) has a sensor element (3) and an optical shielding device (1). The sensor element (3) has a first detection region (35) for detecting measurement radiation (5) and a second detection region (37) for detecting reference radiation (7). The optical shielding device (1) is positioned in relation to the sensor element (33) and fastened and optically separates the first and second detection regions (35, 37) from each other. The optical shielding device (1) further comprises a first recess (16) and a second recess (15) which are permeable to optical radiation of a first wavelength range.