Image Sensor Module Layout Using Brewster Angle to Cut Reflections
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Solution Overview
Problem
Image sensing elements, particularly CMOS image sensors, are prone to interference from undesired reflected light when capturing images through mediums with partial reflection and transmission characteristics, especially under strong ambient light conditions, leading to images being distorted by light reflected from the medium surface rather than the object.
Innovation Solution
The image sensing module incorporates a photoelectric conversion element with a dielectric layer and isolation structures, where the angle of light incidence is set to the Brewster angle at the interface, reducing interference by reflecting unwanted light from the medium surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If image sensing elements are used to capture images through mediums with partial reflection and transmission characteristics, then images of objects in the medium can be obtained, but interference from undesired reflected light from the medium surface occurs
Solution Approach 1:
The patent changes the angle parameter of light incidence to the Brewster angle, which fundamentally alters the reflection characteristics at the interface. At this specific angle, p-polarized light experiences minimal reflection while s-polarized light is reflected, thereby selectively reducing undesired reflected light interference and improving image quality
Solution Approach 2:
The patent introduces a dielectric layer with specific optical properties on the light incident surface of the photoelectric conversion element. This local modification creates different optical characteristics at the interface, enabling selective reflection and transmission of light polarizations to reduce interference from undesired reflected light
2Object-affected harmful factors
If the angle of light incidence is set to the Brewster angle to reduce reflected light interference, then undesired reflected light is minimized, but the structure becomes more complex with specific angular requirements
Solution Approach 1:
The patent sets the light incident surface at a specific angle (Brewster angle) relative to the main board, transforming a potential complexity into a defined geometric parameter. This angular configuration is integrated into the overall module design, achieving interference reduction through precise geometric arrangement rather than additional complex components
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
This configuration significantly reduces the intensity of undesired reflected light collected by the photoelectric conversion element, improving image quality by minimizing interference from medium surfaces.
Implementation Method 1
a second angle is provided between a light beam incident to the light incident surface of the photoelectric conversion element and a normal vector of the light incident surface. The second angle is about equal to the Brewster angle at the interface of the light beam incident to the light incident surface
Data Source
AI summary
The present disclosure provides an image sensing module including a main board and an image sensor. The main board has a first surface and a second surface opposite to each other. The image sensor is disposed on the first surface of the main board and includes a plurality of isolation structures and a photoelectric conversion element between the plurality of isolation structures. A first angle is provided between a light incident surface of the photoelectric conversion element and the first surface of the main board, and a second angle is provided between a light beam incident to the light incident surface of the photoelectric conversion element and a normal vector of the light incident surface. The second angle is about equal to the Brewster angle at the interface of the light beam incident to the light incident surface.