Trapezoidal Wave Drive Signal for Optical Device Vibration Control
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Solution Overview
Problem
Existing optical modulation devices, such as those described in JP-A-2011-158589, face issues with image degradation due to unwanted vibration and short maintenance times of drive signal components, leading to blurred images when trying to enhance image resolution by shifting the axis of image light.
Innovation Solution
An optical device with a moving section supported by a shaft section and actuated by a trapezoidal wave drive signal, where the maintenance time of the flat portion of the drive signal is longer than the swing trajectory, and frequency components are configured to avoid resonance frequencies, using an electromagnetic actuator with a permanent magnet and coil to efficiently swing the moving section and reduce unwanted vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a sine wave drive signal is used to reduce unwanted vibration, then vibration is reduced, but the maintenance time of maximum and minimum values is short causing image degradation
Solution Approach 1:
The drive signal waveform is changed from a sine wave to a trapezoidal wave with extended flat portions at maximum and minimum values. This parameter change allows the maintenance time at extreme positions to be increased, improving image sharpness while the gradual transition portions reduce vibration. The waveform parameters (slope, flat portion duration) are optimized to balance vibration control and image quality requirements.
2Manufacturing precision
If the maintenance time of maximum and minimum values is increased to display a sharper image, then image sharpness is improved, but the moving section vibrates on the opposite side causing blur
Solution Approach 1:
The drive signal uses a trapezoidal waveform where the flat portions at maximum and minimum values are extended to increase maintenance time for sharp image display. Simultaneously, the transition portions between extreme values are designed with gradual slopes to minimize vibration and prevent image blur, thus resolving the contradiction between image sharpness and stability.
3Manufacturing precision
If a trapezoidal wave drive signal is used with extended flat portions, then image sharpness is improved, but the device complexity increases
Solution Approach 1:
The drive signal is configured as a trapezoidal wave with specific parameter relationships: the maintenance time of the flat portion (T1) is set to be longer than the swing trajectory time (T2), and the slope portions are optimized for smooth transitions. These parameter optimizations achieve improved image sharpness while keeping the control system relatively simple through straightforward waveform generation.
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 reduces image degradation, allows for higher image resolution by effectively shifting the optical axis, and simplifies the device design while minimizing unwanted vibrations and environmental temperature effects.
Implementation Method 1
the actuator includes a permanent magnet and a coil that generates an electric field which acts on the permanent magnet
Data Source
AI summary
An optical device includes an optical section, a moving section, a shaft section, and an actuator. The optical section includes a light-incident surface on which light is incident. The moving section supports the optical section and the shaft section swingably supports the moving section. The actuator swings the moving section based on a drive signal having a trapezoidal waveform. A swing waveform representative of a trajectory of the moving section as the moving section is swung has a trapezoidal waveform. A maintenance time of a flat portion of the trapezoidal waveform of the drive signal is shorter than a maintenance time of a flat portion of the trapezoidal waveform of the swing waveform of the moving section.