Optical Module Aperture Edge Features Mitigate Crosstalk
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Solution Overview
Problem
Existing optical modules used as proximity sensors in portable electronic devices face challenges in reducing size while increasing the field of view, which leads to increased optical crosstalk due to high angle rays generated by optical components.
Innovation Solution
The optical modules incorporate edge features in the apertures through which light is emitted and detected, featuring varying widths and profiles along the depth of the apertures to reduce optical crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If optical components are added to increase the field of view, then the field of view is improved, but optical crosstalk increases due to high angle rays
Solution Approach 1:
The patent extracts and removes high angle rays that cause optical crosstalk from the optical path. The aperture edge features are specifically designed to block and remove these harmful high angle rays while allowing useful lower angle rays to pass through, thereby separating the useful light from the harmful light.
Solution Approach 2:
The patent applies different properties to different parts of the aperture by creating edge features with varying widths along the aperture depth. The aperture has a non-uniform structure where the edge width varies, creating local variations in light blocking properties that selectively filter high angle rays while maintaining field of view.
2Volume of moving object
If the size of the optical module is reduced, then the module size is improved, but optical crosstalk increases due to limited space for optical isolation
Solution Approach 1:
The patent implements nesting by placing the aperture edge features within the existing aperture structure of the optical module. The varying width features are integrated into the aperture depth, creating a nested structure that blocks high angle rays without adding external isolation components, thereby maintaining compact module size.
Solution Approach 2:
The patent addresses the 2D aperture problem by introducing a 3D dimension - varying the aperture width along the depth dimension. This creates a three-dimensional aperture structure with non-uniform width that provides optical isolation functionality without increasing the module's external footprint.
Data Source
AI summary
An optical system includes a housing that defines a first aperture and a second aperture different from the first aperture. At least one of the first aperture or the second aperture is defined by a peripheral surface having a plurality of inclined surfaces with respect to a center axis of the first aperture or the second aperture. In some cases, the peripheral surface may define a convex profile, may have a coating or a surface treatment, or may define other edge features that help mitigate optical crosstalk. The optical system may also include an array of light emitters disposed within the housing and configured to emit light through the first aperture and a light detector disposed within the housing and configured to detect a portion of the emitted light that is returned from a target and received through the second aperture.