Spatial Light Modulator Landing Tip for Stiction Reduction
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Solution Overview
Problem
Micro-mirror arrays in spatial light modulators face delays and reliability issues due to stiction between the mirror's lower surface and mechanical stops, affecting their tilt response and overall performance in display devices.
Innovation Solution
The design incorporates a mirror plate with a reflective surface, a substrate, and a landing tip with a laterally extended upper portion and a vertically extended lower portion, which facilitates rotation and reduces stiction by storing elastic energy to assist in mirror plate separation, enhancing mechanical strength and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional mechanical stops are used to limit mirror rotation, then the mirror tilt response is delayed or prevented, but the device complexity is reduced
Solution Approach 1:
The patent introduces a compliant landing tip as an intermediary element between the mirror and the rigid substrate. This landing tip mediates the interaction by providing a compliant contact surface that reduces stiction while still limiting mirror rotation to the desired range, thereby improving response rate without significantly increasing device complexity
Solution Approach 2:
The patent changes the mechanical parameter of the stopping mechanism from rigid to compliant by using a flexible landing tip. This parameter change allows the stopping mechanism to dynamically adapt during mirror motion, reducing contact adhesion and improving tilt response rate while maintaining the essential function of limiting rotation
2Stability of the object's composition
If the mirror contacts the mechanical stop, then the rotation is limited, but stiction causes contact surface adhesion and delays response
Solution Approach 1:
The patent changes the physical state of the stopping surface from rigid to compliant by implementing a flexible landing tip. This parameter change reduces the contact area and contact force during mirror stopping, thereby minimizing stiction and contact surface adhesion while maintaining stable position control
Solution Approach 2:
The patent converts the potentially harmful effect of rigid contact (stiction and adhesion) into a beneficial compliant contact mechanism. The flexible landing tip allows controlled deformation that dissipates contact energy and reduces adhesion forces, transforming the harmful stiction effect into a beneficial damping mechanism that improves reliability
3Reliability
If the landing tip is made compliant to reduce stiction, then the response rate improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent changes the material parameter of the landing tip to be compliant and flexible, which inherently provides tolerance to geometric variations. The compliant nature of the material compensates for manufacturing variations, reducing the stringency of precision requirements while maintaining reliable mirror separation and reducing stiction
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 configuration improves the response rate and reliability of micro-mirrors, increases the active reflection area fill-ratio, and enhances the brightness and contrast of displayed images by minimizing horizontal displacement and stiction, making it suitable for various applications including video displays and photolithography.
Implementation Method 1
The laterally extended upper portion and the vertically extended lower portion can be elastically distorted when pressed by the mirror plate, storing elastic energies in the springy landing tips. The springy landing tips can spring back to push away the mirror plate
Implementation Method 2
circuitry for generating electrostatic forces that tilt the micro mirror plate
Data Source
AI summary
A spatial light modulator includes a mirror plate comprising a reflective upper surface, a lower surface, and a cavity having an opening on the lower surface; a substrate comprising an upper surface, a hinge support post in connection with the upper surface, and a hinge component supported by the hinge support post and in connection with the mirror plate; and a landing tip having a laterally extended upper portion and a vertically extended lower portion in connection with the substrate and the vertically extended lower portion. The laterally extended upper portion can contact the lower surface of the mirror plate to limit the rotation of the mirror plate. The hinge component extends into the cavity and can facilitate a rotation of the mirror plate.