Piezoelectric Sensor Biasing for Light Scanning Mirror Displacement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing light scanning apparatus using piezoelectric sensors suffers from voltage drop due to aging degradation and noise interference, leading to reduced sensitivity and accuracy in mirror displacement detection.
Innovation Solution
A light scanning apparatus is designed with a piezoelectric sensor configuration where a first bias voltage with positive or negative polarity is applied to the upper electrode and a second bias voltage with opposite polarity is applied to the lower electrode, connected through resistors to prevent charge-up and maintain polarization, thereby reducing the influence of aging degradation and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric sensor is used to detect mirror displacement, then the light scanning apparatus can measure displacement, but the output voltage drops due to aging degradation and noise interference occurs
Solution Approach 1:
The patent applies bias voltages with specific polarities to the upper and lower electrodes of the piezoelectric sensor. By changing the electrical parameters (applying positive bias to upper electrode, negative bias to lower electrode), the system maintains stable output voltage and suppresses aging degradation effects, thereby resolving the contradiction between measurement precision and long-term reliability
2Productivity
If the piezoelectric sensor operates continuously, then displacement detection continues, but noise interference increases and sensitivity decreases
Solution Approach 1:
The patent converts the harmful noise interference into a beneficial signal by using the piezoelectric effect in reverse. The bias voltages create a stable operating point that allows the sensor to distinguish between actual displacement signals and noise, thereby maintaining high sensitivity and accuracy for continuous detection operations
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 effectively suppresses the voltage drop and noise interference, maintaining the sensitivity and accuracy of mirror displacement detection over time, improving the signal-to-noise ratio and extending the lifespan of the piezoelectric sensors.
Implementation Method 1
a piezoelectric sensor that is formed on the connection beams and detects displacement of the connection beams caused by a swing of the torsion beams around the axis when the mirror swings by a drive voltage applied to the drive beams
Implementation Method 2
torsion beams that support the mirror supporting portion on opposite sides of the mirror supporting portion along an axis direction of an axis, the mirror supporting portion being swung around the axis direction by torsion of the torsion beams
Data Source
AI summary
A light scanning apparatus includes torsion beams supporting a mirror supporting portion on opposite sides of the mirror supporting portion along an axis direction, the mirror supporting portion being swung around the axis direction by the torsion beams; a pair of drive beams sandwiching the mirror and the mirror supporting portion in a direction orthogonal to the axis direction; connection beams that connect mutually facing sides of each drive beam with the torsion beams; and a piezoelectric sensor formed on the connection beams and detecting displacement of the connection beams caused by a swing of the torsion beams around the axis when the mirror swings by a drive voltage, wherein a first bias voltage having a positive or negative polarity is applied to an upper electrode of the piezoelectric sensor, and a second bias voltage having an opposite polarity is applied to a lower electrode.