Z-axis Thermal Accelerometer Multi-Axis Sensing Integration
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Solution Overview
Problem
Conventional 2-axes thermal accelerometers are not easily configurable to sense acceleration in three dimensions, leading to increased cost and complexity when attempting to implement 3-dimensional structures, making them unsuitable for consumer electronics and automotive applications.
Innovation Solution
A thermal accelerometer device that includes temperature sensing elements on the X and Y axes to detect differential temperatures for X and Y direction accelerations, and a common mode temperature sensing element to detect Z-axis acceleration, with amplification circuitry to enhance sensitivity in the Z direction, allowing for up to three axes of acceleration sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple printed circuit boards are used to create a 3-dimensional accelerometer structure, then acceleration sensing in three dimensions is achieved, but device complexity and cost increase significantly
Solution Approach 1:
The patent merges multiple acceleration sensing functions into a single integrated circuit substrate. The first accelerometer senses acceleration in a first direction and the second accelerometer senses acceleration in a second direction, with both integrated on one substrate rather than requiring separate printed circuit boards. This integration reduces device complexity while maintaining three-dimensional acceleration sensing capability.
Solution Approach 2:
The single substrate serves multiple functions by integrating both the first and second accelerometers, along with shared signal processing circuitry. This multi-functional design allows the device to sense acceleration in multiple directions simultaneously without requiring separate board assemblies, thereby reducing overall system complexity.
2Adaptability or versatility
If multiple printed circuit boards are used to create a 3-dimensional accelerometer structure, then acceleration sensing in three dimensions is achieved, but manufacturing cost increases
Solution Approach 1:
By combining multiple accelerometer functions and signal processing circuits into a single substrate, the patent eliminates the need for multiple printed circuit boards and their associated assembly steps. This integration reduces manufacturing complexity and cost while achieving three-dimensional acceleration sensing.
Solution Approach 2:
The patent segments the acceleration sensing functions into distinct first and second accelerometers on the same substrate, each sensing different directions. This segmentation allows independent optimization of each sensing element while maintaining overall integration, reducing manufacturing cost compared to separate board implementations.
3Adaptability or versatility
If multiple printed circuit boards are used to create a 3-dimensional accelerometer structure, then acceleration sensing in three dimensions is achieved, but reliability decreases
Solution Approach 1:
The patent merges all acceleration sensing and signal processing functions onto a single substrate, eliminating the interfaces and connection points between multiple printed circuit boards. This reduces potential failure points and improves reliability by removing the complexity of multi-board assembly and interconnection.
4Ease of manufacture
If a 2-axes thermal accelerometer is used, then cost is reduced, but acceleration sensing in three dimensions is not achieved
Solution Approach 1:
The patent segments the acceleration sensing into distinct first and second accelerometers on the same substrate, each sensing acceleration in different directions. This segmentation enables three-dimensional sensing capability while maintaining the cost-effectiveness of individual 2-axis thermal accelerometer designs through integration.
Solution Approach 2:
By merging two separate 2-axis thermal accelerometer designs into a single integrated substrate, the patent achieves three-dimensional acceleration sensing without the cost and complexity of a fully 3D structure. The integration shares common components and signal processing, reducing overall cost while enabling multi-axis sensing.
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 provides a low-cost, reliable thermal accelerometer capable of sensing acceleration in three dimensions without the need for multiple printed circuit boards, reducing complexity and increasing reliability for use in consumer electronics and automotive applications.
Implementation Method 1
electrical current is passed through the heater plate, which heats the surrounding air to generate a symmetrical temperature gradient
Implementation Method 2
electrical current is passed through the heater plate, which heats the surrounding air
Implementation Method 3
the temperature distribution of the air shifts. Specifically, when acceleration is applied in the X direction, a differential temperature is detected by the temperature sensors disposed on the X axis
Data Source
AI summary
A thermal accelerometer device that allows up to three axes of acceleration sensing. The thermal accelerometer includes a substantially planar substrate, a cavity formed in the substrate, a heater element, and at least first and second temperature sensing elements. The heater element is suspended over the cavity, and the first and second temperature sensing elements are disposed along the X or Y axis in the substrate plane on opposite sides of and at equal distances from the heater element. The thermal accelerometer employs differential temperatures detected by the temperature sensing elements to provide indications of acceleration in the X or Y directions. Further, the thermal accelerometer employs a common mode temperature detected by the temperature sensing elements to provide an indication of acceleration along a Z axis perpendicular to the X and Y axes.