MEMS Illumination Mitigating Mechanism for Stray Light Noise
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Solution Overview
Problem
MEMS optic sensing devices face issues with noise and parasitic signals due to stray light, which affects the operation by adding unwanted noise and reducing the dynamic measurement range.
Innovation Solution
The implementation of an illumination mitigating mechanism, including a narrow beam light source, collimator, light-absorbing elements, and optical limiters, is used to reduce stray light and its impact on peripheral electronics, such as ESD protection diodes and photodiodes, by distributing light evenly and absorbing or redirecting parasitic illumination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an illumination source is used to provide light for the photodiode, then the sensing function is enabled, but stray light reaches peripheral electronics causing noise and parasitic signals
Solution Approach 1:
An illumination mitigating mechanism is introduced as an intermediary component between the illumination source and the peripheral electronics. This mechanism selectively blocks stray light paths while allowing the intended illumination to reach the photodiode, thus protecting sensitive electronics without compromising the sensing function.
Solution Approach 2:
The illumination mitigating mechanism applies selective light blocking at specific locations and angles. It allows illumination in the desired direction toward the photodiode while blocking stray light in other directions that would otherwise reach peripheral electronics, creating different optical properties in different spatial regions.
2Object-affected harmful factors
If the illumination beam is made narrow to reduce stray light, then less parasitic illumination reaches peripheral electronics, but the light distribution on the photodiode becomes uneven
Solution Approach 1:
The illumination mitigating mechanism introduces a new spatial dimension for light control by positioning light-absorbing elements at specific three-dimensional locations. This allows the system to block stray light paths in three-dimensional space while maintaining proper illumination distribution on the photodiode surface, solving the contradiction between beam narrowness and uniformity.
Solution Approach 2:
Light-absorbing elements are positioned as intermediary components in the optical path to selectively absorb stray light without affecting the main illumination beam. These elements are strategically placed to intercept only the parasitic light paths while leaving the intended illumination undisturbed.
3Object-affected harmful factors
If light-absorbing elements are added to mitigate stray light, then noise and parasitic signals are reduced, but the device complexity increases
Solution Approach 1:
The illumination mitigating mechanism employs thin light-absorbing films or coatings that can be deposited on existing device surfaces. These thin films provide effective stray light absorption without adding significant structural complexity, volume, or manufacturing complexity to the device.
Solution Approach 2:
The light-absorbing elements are integrated and merged with existing device structures such as packaging materials or housing components. This combining approach allows the stray light mitigation function to be achieved without adding separate, independent components, thereby minimizing the increase in device complexity.
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 solution effectively minimizes noise and parasitic signals, enhancing the accuracy and dynamic range of MEMS devices by controlling and reducing the effect of stray light on the electrical signals produced by photodiodes and other peripheral electronics.
Implementation Method 1
Light arriving from the light source is distributed on a photodiode for producing an electrical signal
Implementation Method 2
light-absorbing elements, and optical limiters, is used to reduce stray light and its impact on peripheral electronics
Data Source
AI summary
A micro-opto-electro-mechanical system having a proof mass; at least one illumination source for providing illumination; an illumination detector; peripheral electronics; and an illumination mitigating mechanism for mitigating the effect of illumination emitted from the at least one illumination source on the peripheral electronics. According to various embodiments, the illumination mitigating mechanism includes handles disposed on the proof mass, an illumination collimating device, a substrate with a recess, a narrow beam light source, an illumination absorbing layer or optical limiters.