Asymmetric Sawtooth Waveform for Optical Scan Ringing Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical scanning devices experience image quality deterioration due to ringing caused by resonant oscillation of the mirror part, which is not effectively addressed by existing technologies.
Innovation Solution
A scan driving device and method that generates a sawtooth driving waveform with a rise period and fall period, where one period is shorter than the other and is an integer multiple of the inverse of the natural resonant frequency, to reduce ringing in optical scanning devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a sawtooth driving waveform is used to drive the optical scanning device, then the optical scan velocity can be maintained constant, but ringing is generated due to resonant oscillation of the mirror part causing image quality deterioration
Solution Approach 1:
The patent applies periodic action by making the rise period or fall period of the sawtooth waveform an integer multiple of the inverse natural resonant frequency of the optical scanning device. This periodic synchronization allows the driving waveform to resonate with the natural frequency of the mirror part, thereby reducing ringing effects while maintaining constant optical scan velocity during the scanning operation.
Solution Approach 2:
The patent changes the temporal parameters of the sawtooth driving waveform by adjusting the rise period or fall period to be an integer multiple of the inverse natural resonant frequency. This parameter modification transforms the driving waveform to match the resonant characteristics of the optical scanning device, reducing harmful ringing while preserving the constant scan velocity required for image quality.
2Device complexity
If the rise period and fall period are made equal in the sawtooth driving waveform, then the waveform is symmetric and simple to generate, but ringing occurs due to resonance with the natural frequency of the mirror part
Solution Approach 1:
The patent introduces asymmetry into the sawtooth driving waveform by making either the rise period or fall period an integer multiple of the inverse natural resonant frequency, while the other period remains different. This asymmetric design breaks the symmetry that causes resonance with the mirror part's natural frequency, thereby reducing ringing while maintaining relative simplicity in waveform generation.
3Manufacturing precision
If the time width of rise period and fall period are adjusted to reduce ringing, then image quality improves, but the waveform becomes more complex to generate
Solution Approach 1:
The patent uses periodic action by setting the rise period or fall period to an integer multiple of the inverse natural resonant frequency. This approach improves image quality by reducing ringing through resonant synchronization, while the waveform generation remains relatively simple because it only requires adjusting the time width parameters to match the known resonant frequency of the device, rather than implementing complex filtering or correction circuits.
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 effectively reduces ringing, maintaining constant optical scan velocity and improving image quality by aligning the sawtooth driving waveform with the natural resonant frequency of the optical scanning device, thereby enhancing scan accuracy and image clarity.
Implementation Method 1
a mirror part that is rotated around a rotation axis to deflect light and perform an optical scan to form an image... This invention relates to a scan driving device, an optical scan control apparatus, and a driving waveform generation method... ringing may be generated due to resonant oscillation of the mirror part when the mirror part is driven
Data Source
AI summary
A scan driving device includes a waveform generator that generates a sawtooth driving waveform having a rise period in which a signal level rises, and a fall period in which the signal level falls, and a driving circuit that drives an optical scanning device, that resonates at a natural resonant frequency thereof, by a sawtooth driving voltage waveform corresponding to the sawtooth driving waveform. A time width of one of the rise period and the fall period is shorter than the other of the rise period and the fall period, and is an integer multiple of an inverse number of the natural resonant frequency.