MEMS Radiometer with Vacuum-Sealed Spring Target Plate

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current radiometers, especially those using semiconductor materials, are prone to damage from high-intensity radiation and have accuracy issues due to size constraints and aging, while existing MEMS sensors face challenges in accurately measuring radiation-induced forces with minimal vibration interference.

Innovation Solution

A MEMS radiometer featuring a micro-mechanical spring-supported target plate that displaces perpendicularly in response to radiation, housed in a sealed vacuum chamber, with capacitive or piezoelectric detection to measure displacement and convert it into radiometric data, and an optional array format for increased sensitivity, along with vibration compensation and signal processing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If semiconductor materials are used in radiometers, then light detection capability is achieved, but the materials are damaged by high-intensity radiation and accuracy deteriorates with aging

Engineering Contradiction:
Improvematerial durabilityVSAvoidaccuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent replaces semiconductor-based optical detection with a mechanical detection system. A target plate reflects incident light to a mirror, and the reflected light pattern is detected by a position-sensitive detector. This mechanical/optical system avoids the material damage and aging issues inherent in semiconductor photocells while maintaining light detection capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary mechanical system between the incident light and the detection mechanism. The target plate and mirror assembly serves as an intermediary that converts optical information into mechanical positioning, which is then detected by the position-sensitive detector. This intermediary mechanism protects the detection system from direct exposure to high-intensity radiation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of moving object

If MEMS sensors are used to measure radiation-induced forces, then miniaturization is achieved, but vibration interference affects measurement accuracy

Engineering Contradiction:
Improvesensor sizeVSAvoidmeasurement accuracy
Core Design Contradiction:
Length of moving objectVSMeasurement precision

Solution Approach 1:

The patent segments the detection system into distinct functional components: a target plate for receiving light, a mirror for reflection, and a position-sensitive detector for measurement. This segmentation allows each component to be optimized independently and facilitates vibration isolation strategies for the MEMS sensor elements.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs feedback mechanisms through the position-sensitive detector to continuously monitor the position of the target plate or mirror. This feedback information can be used to compensate for vibration effects and maintain measurement accuracy despite the miniaturized MEMS structure.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If the target plate is made non-deformable, then radiation force measurement accuracy is improved, but the structure becomes more complex

Engineering Contradiction:
Improveforce measurement accuracyVSAvoidstructural complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies local quality by making only the target plate non-deformable while allowing other components like the support structure and detection elements to have appropriate flexibility. This localized constraint ensures accurate force measurement without requiring the entire structure to be rigid, thereby reducing overall complexity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent extracts the deformation function from the target plate itself and transfers it to the measurement system. Instead of allowing the target plate to deform and measure force through its shape change, the system measures the position changes of the plate or associated mirror, separating the force reception function from the measurement function.

Inventive Principle:
Principle #2Taking out (Extraction)

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 radiometer accurately measures radiation-induced forces with high sensitivity and minimal vibration interference, maintaining accuracy even in high-intensity radiation environments and extending device lifespan by avoiding material degradation.

Implementation Method 1

a micro-mechanical spring which supports the target plate above the base support and allows for displacement of the target plate due to a force imparted by received radiation

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a micro-mechanical spring which supports the target plate above the base support and allows for displacement of the target plate due to a force imparted by received radiation

Methodology Applied
Scientific EffectRadiation pressure: Radiation Pressure

Implementation Method 3

with capacitive or piezoelectric detection to measure displacement and convert it into radiometric data

Methodology Applied
Scientific EffectCapacitive detection: Capacitance

Implementation Method 4

with capacitive or piezoelectric detection to measure displacement and convert it into radiometric data

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP1832859B1MEMS radiometer
Publication Date: 2015.12.30 STMICROELECTRONICS INC
  • EP1832859B1 patent drawingFigure 1~3
  • EP1832859B1 patent drawingFigure 4~5D
  • EP1832859B1 patent drawingFigure 6

AI summary

A radiometer sensor includes a target plate and a micro-mechanical spring which supports the target plate above a base support. This construction allows for displacement of the target plate in a direction perpendicular to the base support in response to radiation which is received by a top surface of the target plate. The sensor is enclosed within a housing that defines a sealed interior chamber within which a vacuum has been drawn. The target plate preferably is non-deformable in response to received radiation. Capacitive or piezoelectric sensors are provided to detect the displacement of the target plate, and the measured displacement is correlated to determine a received radiation level. Radiometer sensor output signals are quantized and signal processed so as to make a radiation level determination.