Optical Sensor Grating Structure for Higher SNR in Compact Modules
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Solution Overview
Problem
Conventional optical sensing modules in portable devices face challenges in increasing signal-to-noise ratio (SNR) without restricting the geometric structure, which affects both proximity and ambient light sensors, and become difficult to produce as component sizes decrease.
Innovation Solution
An optical sensing module with a grating structure comprising multiple parallel wires perpendicular to the optical sensor direction is used, acting as a polarizer to reduce noise and increase SNR by narrowing the field of view, while allowing the desired light to pass through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a geometric structure (opening) is used to narrow the field of view of the proximity sensor to increase SNR, then the SNR of the proximity sensor is improved, but the field of view of the ambient light sensor is also narrowed affecting its operation
Solution Approach 1:
The patent divides the optical path control into separate functional elements: a first opening for the proximity sensor and a second opening for the ambient light sensor. This segmentation allows each sensor to have its own optimized field of view without mutual interference, resolving the contradiction between improving proximity sensor SNR and maintaining ambient light sensor functionality.
Solution Approach 2:
The patent applies different geometric structures to different locations: a first geometric structure (first opening) is provided above the proximity sensor with specific dimensions to control its field of view, while a second geometric structure (second opening) is provided above the ambient light sensor with different dimensions to control its field of view. This local differentiation allows each sensor to operate optimally without compromising the other.
2Volume of moving object
If the size of components is reduced, then the device becomes more compact, but the allowable tolerance range is reduced making it difficult to produce the desired geometric structure
Solution Approach 1:
The patent changes the parameters of the geometric structures by providing specific dimension ranges for the first and second openings that are optimized for compact devices. The first opening has a first dimension and the second opening has a second dimension, with specific tolerance specifications that accommodate miniaturization while maintaining manufacturability. This allows the device to be compact without requiring excessively tight tolerances that would be difficult to achieve in production.
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 grating structure effectively enhances the SNR of the optical sensing module by reducing noise and allowing precise control over the field of view, enabling improved performance without the precision challenges of traditional geometric structures, especially in smaller device designs.
Implementation Method 1
an optical sensing module with a grating to overcome the drawbacks of the conventional optical sensing module
Data Source
AI summary
An optical sensing module has a light source and an optical sensing integrated circuit device. The optical sensing integrated circuit device has an optical sensor and a grating. The optical sensor and the light source are arranged along a first direction. The grating is formed over the optical sensor and has multiple parallel wires. The multiple wires are perpendicular to the first direction.