Angled Aperture Structure for Optical Module 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 introduced to reduce crosstalk by minimizing light reflections, featuring internal angled surfaces on at least three sides and potentially an external angled surface, positioned to minimize light reflections towards the receive portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional aperture is used in the optical module, then the structure is simple, but crosstalk between transmit and receive sides occurs due to light reflections from surfaces
Solution Approach 1:
The patent applies curvature by introducing angled surfaces (non-planar faces) on the aperture structure. Specifically, the aperture includes first and second angled surfaces that are not perpendicular to the base, creating a curved/angled geometry that redirects reflected light away from the receive side, thereby reducing crosstalk while maintaining a relatively simple overall structure
Solution Approach 2:
The patent employs asymmetry by creating an aperture structure where the angled surfaces are positioned and oriented specifically to address crosstalk from particular directions. The first and second angled surfaces are configured asymmetrically relative to the base aperture, allowing selective redirection of harmful reflections while maintaining the functional opening for light transmission
2Object-affected harmful factors
If light reflections are minimized by adding angled surfaces, then crosstalk is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying angular parameters for the angled surfaces (first and second angled surfaces with defined orientations relative to the base). By controlling these angular parameters, the design optimizes the redirection of reflected light while providing manufacturing guidelines that balance precision requirements with manufacturability
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 aperture effectively reduces crosstalk, leading to improved distance determination accuracy by minimizing integrated power, channel 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
Data Source
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.