Asymmetric Light-Transmissive Cover for MEMS Mirror Reflection Control
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Solution Overview
Problem
Image display apparatuses using MEMS mirrors suffer from image distortion due to reflected light from the light-transmissive cover mixing with the projected image, leading to deteriorated picture quality, as existing solutions fail to effectively suppress both external and internal reflected lights.
Innovation Solution
An optical scanning device with a light-transmissive cover having non-parallel first and second planes, ensuring that first and second reflected lights are directed away from the image-projected area, while the third reflected light is directed towards the screen, utilizing a sealing unit to prevent unwanted reflections from entering the image area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a light-transmissive cover is used to protect the MEMS mirror, then protection and sealing are improved, but reflected light from the cover mixes with the projected image, deteriorating picture quality
Solution Approach 1:
The light-transmissive cover is designed with an asymmetric wedge shape where the first plane and second plane are non-parallel to each other. This asymmetric geometry ensures that reflected light from either plane does not return parallel to the incident light path, preventing it from mixing with the projected image while maintaining protection and sealing functions.
Solution Approach 2:
The patent converts the harmful reflected light into a beneficial directional separation. By designing the cover with non-parallel planes at specific angles, the reflected light is redirected away from the optical path in a controlled manner, transforming the potential harm into a functional feature that separates unwanted reflections from the image projection path.
2Object-affected harmful factors
If the external plane and reflection plane are made non-parallel to suppress reflected light, then picture quality is improved, but the structure becomes more complex
Solution Approach 1:
The patent merges the protection function, sealing function, and light reflection control function into a single integrated light-transmissive cover component. The wedge-shaped cover simultaneously provides mechanical protection, environmental sealing, and optical reflection management, eliminating the need for separate components and reducing overall structural complexity despite the non-parallel plane design.
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
Prevents unnecessary reflected lights from mixing into the image-projected area, thereby improving picture quality and allowing for higher scanning speeds and reduced heat liberation, enhancing the overall performance of the image display apparatus.
Implementation Method 1
a first reflected light and a second reflected light reach areas that are different from an image-projected area... the first reflected light being caused to occur such that a partial light of the light that is entering the first plane is reflected by the first plane, and the second reflected light being caused to occur such that a partial light of the light that has passed through the first plane is reflected by the second plane
Data Source
AI summary
An optical scanning device includes a rotationally-moving mirror on which a reflection plane is provided in a rotationally-movable manner, and a sealing unit over which a light-transmissive cover is provided, a first plane of the light-transmissive cover, a second plane of the light-transmissive cover, and the reflection plane of the rotationally-moving mirror within a rotationally-moving range being non-parallel to each other, the first plane being on the opposite side to the side of the rotationally-moving mirror, the second plane being on the side of the rotationally-moving mirror.