Optical Scanner Impedance Conversion Circuit for Head-Up Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Optical scanning devices face issues with weak sensor signals being influenced by downstream circuit loads and electromagnetic induction between wires, leading to operational instability.
Innovation Solution
Incorporating an impedance conversion circuit using a field-effect transistor to receive and convert sensor signals from a piezoelectric sensor, while separating sensor and driving signal wiring to prevent interference, and utilizing high humidity-resistant materials to maintain insulation resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a piezoelectric sensor is used to detect mirror rotational angle, then measurement capability is provided, but sensor signal becomes weak at low frequencies and is influenced by downstream circuit loads and electromagnetic induction
Solution Approach 1:
An impedance conversion circuit is introduced as an intermediary component between the piezoelectric sensor and the downstream circuit. This circuit converts the high-impedance sensor signal to a low-impedance signal, acting as a buffer that isolates the sensor from downstream circuit loads and electromagnetic interference, thereby maintaining signal stability while preserving measurement capability
Solution Approach 2:
The impedance conversion circuit changes the electrical parameter (impedance) of the sensor signal from high to low. This parameter transformation allows the signal to become less susceptible to downstream circuit influences and electromagnetic induction, resolving the reliability issue while maintaining the measurement function
2Device complexity
If sensor wiring and driving signal wiring are placed together, then device complexity is reduced, but electromagnetic induction between wires causes interference
Solution Approach 1:
The impedance conversion circuit serves as an intermediary that electrically isolates the sensor wiring from the driving signal wiring. By converting the sensor signal impedance locally, it allows separate routing of sensor and driving wires without significant electromagnetic coupling, reducing interference while maintaining reasonable device complexity
Solution Approach 2:
The wiring system is segmented into separate sensor signal paths and driving signal paths. The impedance conversion circuit creates distinct electrical zones, allowing wires to be routed separately to minimize electromagnetic induction between them, thus reducing interference while managing complexity
3Adaptability or versatility
If generic components are used in downstream circuit, then adaptability and versatility are improved, but circuit load influences weak sensor signals
Solution Approach 1:
The impedance conversion circuit acts as a protective intermediary between the sensitive piezoelectric sensor and the generic downstream circuit components. It buffers the sensor from varying circuit loads that would otherwise directly affect the weak sensor signal, enabling the use of versatile generic components while maintaining signal reliability
Solution Approach 2:
By transforming the signal impedance from high to low, the circuit changes the electrical characteristics to be more compatible with generic downstream components. This parameter change enables broader component compatibility while the impedance conversion maintains signal integrity against varying loads
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 enhances the stability of sensor signals by preventing interference from downstream circuit loads and electromagnetic induction, allowing for improved flexibility in downstream circuit design and versatility in using generic components, even in high-humidity environments.
Implementation Method 1
a piezoelectric sensor that outputs a sensor signal corresponding to a rotational angle of the mirror
Implementation Method 2
an impedance conversion circuit that receives the sensor signal from the piezoelectric sensor, performs impedance conversion on the received sensor signal, and outputs the impedance-converted sensor signal
Data Source
AI summary
An optical scanning device includes an optical scanner including a mirror that includes a light reflection surface, a driving source that causes the mirror to rotate around a rotation axis passing through the center of the light reflection surface in response to a driving signal, and a piezoelectric sensor that outputs a sensor signal corresponding to a rotational angle of the mirror around the rotation axis; and an impedance conversion circuit that receives the sensor signal from the piezoelectric sensor, performs impedance conversion on the received sensor signal, and outputs the impedance-converted sensor signal.