Angled Optical Aperture for ToF Sensor Crosstalk Reduction
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Solution Overview
Problem
Optical modules, such as ToF sensors, suffer from external crosstalk between the transmit and receive sides, leading to errors in distance determinations due to light reflections from surfaces other than the subject.
Innovation Solution
An aperture with a generally rectangular main body having angled surfaces is positioned to reduce crosstalk by minimizing light reflections, featuring internal angled surfaces on at least three sides and optionally an external angled surface, constructed separately or integrated into the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional aperture with flat surfaces is used, then the structure is simple and easy to manufacture, but light reflections cause crosstalk between transmit and receive sides
Solution Approach 1:
The aperture structure applies different surface characteristics to different regions: the internal surfaces facing the transmit side are angled at specific angles (e.g., 45 degrees) to redirect light, while other surfaces may remain flat. This local differentiation of surface quality allows the aperture to selectively manage light paths, reducing crosstalk where needed while maintaining structural simplicity elsewhere.
Solution Approach 2:
The invention transitions from a conventional two-dimensional flat aperture surface to a three-dimensional structure with angled internal surfaces. By introducing angular dimensions to the aperture geometry, the light reflection paths are redirected away from the receive side, effectively adding a spatial dimension to the light management strategy and reducing crosstalk.
2Measurement precision
If an aperture with multiple angled surfaces is used, then crosstalk is reduced, but manufacturing complexity increases
Solution Approach 1:
The invention specifies particular angular parameters for the internal surfaces (e.g., 45-degree angles) that optimize light redirection while considering manufacturability. By standardizing these angular parameters, the design achieves effective crosstalk reduction through controlled light paths, while the repetition of standard angles across multiple surfaces facilitates consistent manufacturing processes.
3Adaptability or versatility
If the aperture is constructed separately from the housing, then manufacturing flexibility is improved, but assembly complexity increases
Solution Approach 1:
The aperture is designed as a separate, modular component that can be manufactured independently from the housing. This segmentation allows for specialized aperture fabrication processes and quality control while enabling the aperture to be adapted to different housing configurations. The modular design facilitates easier replacement and customization of the aperture component.
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
Reduces crosstalk by minimizing light reflections, improving distance determination accuracy and reducing integrated power and mean irradiance, while potentially increasing peak irradiance.
Implementation Method 1
Crosstalk occurs when light from the Tx side is reflected from a surface other than the subject (e.g., the cover glass or internal structures) to the Rx side. The aperture comprises a generally rectangular main body having four sides and defining a hole therethrough. Each side has at least a top surface and an inside surface. At least three of the four sides have an internal angled surface between their respective top and inside surfaces.
Data Source
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AI summary
In accordance with various embodiments of the present disclosure, an aperture for a transmit portion of an optical module is provided. In some embodiments, the aperture comprises a generally rectangular main body having four sides and defining a hole therethrough. Each side has at least a top surface and an inside surface. At least three of the four sides have an internal angled surface between their respective top and inside surfaces.