MEMS Driving Member for Display Devices
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Solution Overview
Problem
Current driving members, particularly those using amorphous silicon (a-Si) TFTs, face limitations in high current switch ratio, carrier mobility, and power saving, which are insufficient for next-generation display devices requiring faster response and more complex signal processing, and are hindered by high equipment costs and yield issues.
Innovation Solution
A novel driving member based on micro-electro-mechanical systems (MEMS) design, incorporating a first and second suspending beam module and a conductive suspending beam module, which electrically contacts and disconnects based on voltage thresholds, allowing for high carrier mobility and low-temperature manufacturing, thereby improving display device performance and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If amorphous silicon TFT is used as driving member, then low temperature manufacturing is achieved, but carrier mobility and current switch ratio are insufficient
Solution Approach 1:
The patent replaces the traditional semiconductor-based electrical switching mechanism with a MEMS-based mechanical switching system. The suspending beam physically moves to make or break electrical contact, substituting the semiconductor's electrical property control with a mechanical motion system. This allows the use of amorphous silicon at low temperatures while achieving high carrier mobility through the mechanical contact mechanism rather than semiconductor material properties.
Solution Approach 2:
The patent changes the operational parameter from relying on semiconductor material properties (carrier mobility inherent to the material) to relying on mechanical contact parameters (contact resistance, contact pressure, beam displacement). By changing from an electrical property-based system to a mechanical property-based system, the patent overcomes the limitation of amorphous silicon's low carrier mobility while maintaining low-temperature manufacturing advantages.
2Reliability
If compound semiconductors with different doping densities are used, then current switch ratio is improved, but equipment cost and manufacturing complexity increase
Solution Approach 1:
The patent replaces the complex semiconductor doping process with a simple mechanical switching mechanism. Instead of requiring multiple doping processes to achieve different carrier concentrations and improve current switch ratio, the patent uses a mechanically actuated contact system where the current switch ratio is determined by the mechanical contact state (closed or open) rather than material composition. This dramatically simplifies the manufacturing process while achieving high current switch ratio.
3Temperature
If polycrystalline silicon TFTs are manufactured in low temperature process, then manufacturing temperature is reduced, but yield and equipment cost remain problematic
Solution Approach 1:
The patent replaces the polycrystalline silicon TFT structure with a MEMS suspending beam structure. The low-temperature manufacturing advantage is preserved by using amorphous silicon or simple metal structures that can be fabricated at low temperatures, while the yield issue is resolved by using a mechanical switching mechanism that is less sensitive to material defects and manufacturing variations compared to semiconductor devices.
4Ease of manufacture
If traditional a-Si TFT driving members are used, then manufacturing simplicity is maintained, but leakage current is high and power saving is limited
Solution Approach 1:
The patent replaces the electrical field-effect control mechanism of a-Si TFT with a mechanical contact mechanism. In the traditional a-Si TFT, leakage current occurs due to the finite off-state current of the semiconductor device. In the MEMS-based design, the mechanical open state provides a physical discontinuity in the electrical path, dramatically reducing leakage current. The manufacturing simplicity is maintained by using straightforward suspending beam structures that can be fabricated using standard low-temperature processes.
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 MEMS-based driving member achieves higher carrier mobility, reduces leakage current, and enhances the current switch ratio, providing a more competitive solution for next-generation display devices while simplifying the manufacturing process and reducing costs.
Implementation Method 1
when an electric field force formed between the first suspending beam module and the second suspending beam module is larger than a deforming force threshold of the first suspending beam, the first suspending beam module electrically contacts with the conductive suspending beam module
Implementation Method 2
when the electric field force is smaller than the deforming force threshold of the first suspending beam, the first suspending beam module rebounds to an original shape thereof
Data Source
AI summary
An exemplary driving member and an exemplary array module formed by a plurality of the driving members are disclosed in the invention. The driving member includes a first suspending beam module, a second suspending beam module and a conductive suspending beam module. When a voltage is provided between the first suspending beam module and the second suspending beam module, or the first suspending beam module and the second suspending beam module are provided with two homopolar voltages, when the electric field force is larger than the deforming force threshold of the first suspending beam, the first suspending beam moves to contact with the conductive suspending beam module, so that the first suspending beam has a voltage same with the conductive suspending beam module. When the electric field force is smaller than the deforming force threshold of the first suspending beam, the first suspending beam module rebounds to an original state.