Optical Scanning Unit Vibration Control for Video Device Brightness
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Solution Overview
Problem
Existing scanning fiber devices face issues with uneven brightness and reduced image quality due to decreased moving speed at the center of spiral scanning trajectories, especially when applied to video devices with different horizontal and vertical resolutions, requiring more rotations to achieve required resolution and increased control and processing time for vibration management.
Innovation Solution
A video device with an optical scanning unit that includes a light guide path and a vibration unit, where the scanning trajectory control unit generates drive signals with different phases and amplitudes for independent vibration in two directions, allowing for controlled scanning trajectories and speed, and a counter measures the number of cycles to adjust phases and perform optical scanning with varying trajectories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If spiral scanning is performed with constant vibration frequency at resonance frequency, then the optical fiber vibrates stably, but the moving speed at the center portion decreases extremely causing uneven brightness
Solution Approach 1:
The patent applies dynamics by making the vibration frequency variable rather than constant. The control unit adjusts the vibration frequency dynamically during the scanning process, specifically reducing frequency when the optical fiber approaches the center position and increasing it when moving outward. This dynamic frequency adjustment maintains stable vibration characteristics throughout the scanning trajectory while preventing excessive speed reduction at the center portion, thereby resolving the contradiction between vibration stability and moving speed.
2Shape
If spiral scanning trajectory is used with equal scan lines, then the scanning pattern is symmetric, but a larger number of rotations are necessary for different resolutions such as 4:3 and 16:9
Solution Approach 1:
The patent applies parameter changes by modifying the vibration frequency parameter dynamically during scanning. The control unit adjusts the frequency based on the real-time position of the optical fiber, reducing frequency near the center and increasing it at outer positions. This parameter adjustment effectively changes the scanning trajectory characteristics, allowing the system to achieve different resolution requirements (4:3, 16:9 aspect ratios) with fewer rotations while maintaining the beneficial symmetric scanning pattern.
3Stability of the object's composition
If the optical fiber returns to the center position in substantially non-vibration state, then the trajectory is complete, but control and processing time are necessary for preventing vibration
Solution Approach 1:
The patent applies preliminary action by proactively adjusting the vibration frequency before the optical fiber reaches positions where vibration control would be difficult. The control unit reduces the vibration frequency in advance when the fiber approaches the center region, preventing excessive vibration buildup rather than attempting to stop it afterward. This preliminary frequency reduction eliminates the need for separate control and processing time to prevent vibration, as the vibration is naturally minimized through the frequency adjustment strategy.
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 solution enables high image quality with reduced uneven brightness and fewer rotations, effectively addressing the challenges of different resolutions by controlling the scanning trajectory and speed, thereby improving image quality and resolution without increasing the number of rotations.
Implementation Method 1
a vibration unit configured to apply vibration to the light guide path via a joint unit in a vicinity of the other end of the light guide path
Implementation Method 2
spiral scanning is performed through the vibration at the tip portion of the optical fiber by an actuator that can vibrate on two axes... a vibration frequency is set to a resonance frequency
Implementation Method 3
disposing a piezoelectric element in a vicinity of a supporting portion, the optical fiber can vibrate
Data Source
AI summary
To propose an optical scanning method for a video device including an optical scanning unit in which one end of a light guide path has a protruding beam-shaped structure. The video device includes the optical scanning unit having the light guide path in which light enters from one end and emits from the other end, and a vibration unit configured to apply vibration to the light guide path via a joint unit in a vicinity of the other end of the light guide path; a drive signal generation unit that generates a drive signal for inducing vibration in the vibration unit; and a scanning trajectory control unit which has a function of independently vibrating the light guide path in a first direction substantially perpendicular to an optical axis direction of the light guide path, and in a second direction substantially perpendicular to the optical axis direction of the light guide path and substantially perpendicular to the first direction by the vibration unit, and which generates a first drive signal configured to drive the vibration unit in the first direction and a second drive signal configured to drive the vibration unit in the second direction with any pattern. The scanning trajectory control unit generates the first drive signal and the second drive signal as sine waves having different phases and a substantially same frequency, and sets a modulation amount of an amplitude modulation of a sine wave of the second drive signal to be larger than a modulation amount of an amplitude modulation of a sine wave of the first drive signal.