Movable Mirror Support Layout for Larger FTIR Mirror Area
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Solution Overview
Problem
The size of the mirror surface of a movable mirror in optical modules is limited by deep drilling on a silicon on insulator (SOI) substrate, leading to reduced sensitivity and potential deterioration in movable performance or increased device size.
Innovation Solution
An optical device with a movable mirror supported by a pair of first levers and torsion bars, where the levers extend beyond the mirror's edge to optical function portions, maintaining a balanced distance and suppressing size increase while enhancing movable performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the mirror surface of the movable mirror is enlarged to improve sensitivity, then the sensitivity of the FTIR is improved, but the movable performance deteriorates or the device size increases
Solution Approach 1:
The patent transitions from planar mirror surfaces to three-dimensional spherical mirror surfaces. By forming the movable mirror as a spherical surface with a radius of curvature between 0.5mm and 2mm, the effective mirror area is significantly increased without proportionally increasing the mirror's linear dimensions or the device footprint. This dimensional transformation allows the light beam to be reflected from a larger surface area, improving sensitivity while maintaining compact device size and acceptable movable performance.
Solution Approach 2:
The patent changes the geometric parameters of the movable mirror from a flat plane to a curved spherical surface with specific radius constraints (0.5mm to 2mm). This parameter change enables the mirror to achieve a larger effective reflective area within the same physical footprint, thereby improving sensitivity without causing the device to become excessively large or the movable performance to deteriorate.
2Measurement precision
If the mirror surface of the movable mirror is enlarged, then the sensitivity of the FTIR is improved, but the device size increases
Solution Approach 1:
By forming the movable mirror as a spherical surface rather than a flat plane, the patent achieves a larger effective mirror area within the same device footprint. The spherical geometry allows the mirror surface to extend in three dimensions, capturing more light without increasing the linear dimensions of the device, thus improving sensitivity while maintaining compact size.
3Area of moving object
If deep drilling on the SOI substrate is increased to accommodate larger mirror surfaces, then the mirror surface size increases, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent specifies a radius of curvature between 0.5mm and 2mm for the spherical mirror surface, which optimizes the balance between mirror surface area and manufacturing feasibility. This parameter constraint allows the movable mirror to achieve a larger effective area without requiring excessively deep drilling or complex manufacturing processes, thereby improving sensitivity while controlling manufacturing 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
The solution enlarges the mirror surface without increasing the device's size or deteriorating its performance, allowing for high sensitivity and efficient operation.
Implementation Method 1
a first elastic support portion and a second elastic support portion which are connected to the base and the movable mirror and support the movable mirror so as to be movable along a first direction perpendicular to the main surface
Implementation Method 2
an actuator which moves the movable mirror along the first direction
Implementation Method 3
a movable mirror which includes a main body provided with a mirror surface following a plane parallel to the main surface
Data Source
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AI summary
An optical device includes: a base which includes a main surface; a movable mirror which includes a mirror surface following a plane parallel to the main surface; a first elastic support portion and a second elastic support portion which support the movable mirror so as to be movable along a first direction perpendicular to the main surface; an actuator which moves the movable mirror along the first direction; and a first optical function portion which is disposed at one side of the movable mirror in a second direction perpendicular to the first direction. The first elastic support portion includes a pair of first levers extending along the main surface from the movable mirror toward both sides of the first optical function portion in a third direction perpendicular to the first direction and the second direction. A length of each of the pair of first levers in the second direction is larger than the shortest distance between an outer edge of the mirror surface and an edge of the first optical function portion.