Micromirror Stop Unit for Impact Protection
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Solution Overview
Problem
Micromirrors in micromirror assemblies are prone to deformation and fracture due to excessive freedom of movement during rapid movements or impacts, leading to potential damage of supporting components, especially when the mirror's mass inertia causes stress on these components during falls or shocks.
Innovation Solution
Incorporating a stop unit that restricts the mirror's movement in a predefined direction, particularly where it has the greatest kinetic energy absorption, to enhance stability and ruggedness by slowing down the mirror's mass directly and reducing stress on intermediate pieces, while utilizing a torsion spring and drive frame with rails and stops formed from a single silicon substrate for optimal manufacturing and protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the silicon layer is made significantly thicker than the silver layer to avoid thermal strain deformation, then the mirror's thermal stability is improved, but the mass of the mirror is significantly increased
Solution Approach 1:
The patent changes the physical parameters of the mirror structure by making the silicon layer significantly thicker than the silver layer (thickness ratio of at least 10:1). This parameter change resolves the thermal strain issue by providing sufficient structural support to prevent deformation during rapid movements, while accepting the increased mass as a necessary trade-off for thermal stability.
2Stability of the object's composition
If the mirror mass is increased to prevent thermal strain deformation, then the thermal stability is improved, but the damage risk to supporting elements during impact is increased
Solution Approach 1:
The patent applies beforehand cushioning by introducing a stop unit that restricts the mirror's movement in the event of a fall or impact. This stop unit acts as a protective measure that engages before catastrophic damage can occur, limiting the travel distance of the heavy mirror and preventing fracture of suspension elements or springs by absorbing or dissipating the impact energy.
Solution Approach 2:
The stop unit serves as an intermediary element between the heavy mirror and the supporting suspension elements. It mediates the impact forces by providing a mechanical stop that prevents the mirror from traveling far enough to cause damage to the fragile suspension components, thus protecting the system from the harmful effects of the mirror's own mass.
3Adaptability or versatility
If the mirror is allowed to move freely in all directions, then the operational flexibility is improved, but the risk of fracture during rapid movement is increased
Solution Approach 1:
The patent applies segmentation by dividing the movement constraints into different directions. The stop unit restricts movement only in the vertical direction (preventing falls and excessive downward travel) while allowing the mirror to maintain its operational freedom for tilting and scanning movements. This selective segmentation of movement freedom resolves the contradiction by protecting against fracture in the critical vertical direction while preserving operational flexibility in the functional directions.
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 effectively prevents damage to the micromirror assembly by restricting movement in the direction of greatest kinetic energy, increasing stability and ruggedness, and optimizing the use of space and manufacturing simplicity, while ensuring the mirror's reflective surface is protected and light flow is maintained.
Implementation Method 1
a spring-mounted mirror, in particular a mirror which is spring-mounted by means of a torsion spring situated below the mirror
Implementation Method 2
at least one stop unit, which is designed to restrict the movement of the mirror in the event of a movement of the mirror in a predefined direction out of its idle position
Data Source
AI summary
A micromirror assembly is described as including a spring-mounted mirror and at least one stop unit, which is designed to restrict a movement of the mirror in the event of a movement of the mirror in a predefined direction out of its idle position. Furthermore, the invention relates to a projection device.