Load Sensor with Vertical Transistors for Direction Detection
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Solution Overview
Problem
Existing load sensors face challenges in miniaturization and high-density formation while detecting both the magnitude and direction of loads, particularly in distinguishing between vertical and horizontal loads applied to complex-shaped objects, due to limitations in adhesive material usage and separation of load detection mechanisms.
Innovation Solution
A load sensor design incorporating vertical transistors with a substrate and rib structure, featuring a gate electrode, gate insulation film, and semiconductor thin film on the rib's side surface, allowing for the detection of load magnitude and direction through controlled channel region formation and electric current changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If adhesive material is used to attach a thin film sensor to the convex portion of an elastic body, then the sensor can be formed on the side surface, but miniaturization and high-density formation become difficult
Solution Approach 1:
The sensor is divided into multiple independent vertical transistors, each capable of detecting loads in different directions. This segmentation allows for high-density integration of multiple sensors on the same elastic body surface, overcoming the limitation of adhesive-based thin film sensors that难以 achieve high-density formation.
Solution Approach 2:
The invention transitions from planar thin film sensors to three-dimensional vertical transistor structures. The vertical channel configuration allows current flow in the vertical direction while detecting horizontal loads, utilizing the third dimension to resolve the contradiction between ease of manufacture and manufacturing precision for miniaturization.
2Device complexity
If a single sensor configuration is used on the elastic body, then the structure is simple, but the ability to detect both magnitude and direction of loads is limited
Solution Approach 1:
Each vertical transistor is designed to detect loads in multiple directions through its geometric configuration. The channel direction of each transistor can detect loads perpendicular to its channel, allowing a single sensor structure to serve multiple detection functions, thus improving measurement precision without proportionally increasing device complexity.
Solution Approach 2:
The vertical transistors are arranged with asymmetric orientations relative to the convex portion of the elastic body. By positioning transistors at different angles (e.g., 45 degrees relative to each other), the system can detect load directions in two-dimensional space, enabling precise direction detection while maintaining relatively simple device structure.
3Ease of manufacture
If vertical transistors are formed on the side surface of a rib with trapezoidal shape, then thin-film technology can be used, but separation between vertical load detection and horizontal load detection remains difficult
Solution Approach 1:
Different regions of the elastic body are equipped with vertical transistors having different channel orientations. Each local region's transistor configuration is optimized for detecting specific load directions, allowing the system to distinguish between vertical and horizontal loads through spatial differentiation of sensor responses.
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
Enables accurate detection of both load magnitude and direction without the limitations of miniaturization and high-density formation, improving tactile sensing capabilities for complex-shaped objects by differentiating between vertical and horizontal loads.
Implementation Method 1
Each of the at least two vertical transistors includes: a gate electrode, a gate insulation film, and a semiconductor thin film which are arranged on the side surface of the rib; a bottom electrode layer arranged on a bottom of a concave portion of the substrate so as to contact the semiconductor thin film
Implementation Method 2
When loaded, the sensor can detect the magnitude and the direction of a load by detecting distortion applied to a convex portion of the elastic body
Data Source
AI summary
A load sensor includes: a substrate; a rib on the substrate; and two vertical transistors. Each vertical transistor includes: a gate electrode, a gate insulation film, and a semiconductor thin film on the side surface of the rib; a bottom electrode layer on a bottom of the substrate, on which the rib is not arranged, with contacting the semiconductor thin film; and a top electrode layer on a top of the rib with contacting the semiconductor thin film. Each vertical transistor flows current between the bottom electrode layer and the top electrode layer when a channel region is provided in the semiconductor thin film. Each straight line along normal line directions of the channel regions in the vertical transistors is arranged on a different side surface of the rib from each other, and has a predetermined angle between the straight lines.