Optical Scanner Synchronization via Vertical Frequency Locking
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Solution Overview
Problem
Optical scanners in projectors face challenges in maintaining synchronization with varying resonance frequencies due to process variations and light intensity changes, leading to driving errors and image distortion.
Innovation Solution
A projector system that includes a video processor and scanner driver to synchronize the optical scanner with a vertical synchronization signal, adjusting the number of horizontal lines scanned to maintain uniform horizontal and locked vertical frequencies, using a sensing signal processor to generate reference signals for driving the scanner and controlling output timing of video data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the optical scanner operates at high driving speed to generate high-definition images, then the driving angle increases and image quality improves, but the resonance frequency varies due to process variation and light intensity changes, causing driving errors and image distortion
Solution Approach 1:
The patent employs a feedback mechanism where the actual vertical frequency of the optical scanner is measured and compared with the target vertical frequency. Based on this comparison, the number of horizontal lines is adjusted to correct frequency deviations, ensuring stable synchronization despite variations in resonance frequency caused by high-speed operation
Solution Approach 2:
The patent dynamically changes the parameter of horizontal line count based on the detected vertical frequency deviation. By adjusting the number of horizontal lines, the system compensates for resonance frequency variations and maintains accurate synchronization between the optical scanner and video data
2Stability of the object's composition
If the number of horizontal lines is increased to maintain synchronization, then vertical frequency stability improves, but the complexity of controlling the optical scanner increases
Solution Approach 1:
The system performs self-adjustment by automatically detecting its own vertical frequency deviation and correcting it through horizontal line count modification. This self-service mechanism eliminates the need for external complex control systems while maintaining vertical frequency stability
3Measurement precision
If the resonance frequency is adjusted to match driving signals, then synchronization accuracy improves, but the time required to stabilize the optical scanner increases
Solution Approach 1:
The patent performs preliminary detection of the vertical frequency deviation at the start of operation and immediately adjusts the horizontal line count to achieve accurate synchronization. This preliminary action approach minimizes stabilization time while ensuring high synchronization accuracy from the beginning
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 ensures stable operation of the optical scanner, maintaining image quality by synchronizing vertical and horizontal frequencies, preventing image distortion and reducing memory requirements by ensuring input and output vertical frequencies match.
Implementation Method 1
The projector scans a screen with a beam generated from a laser source using the optical scanner to form an image on the screen
Implementation Method 2
A specific frequency of the driving signal, which increases the driving angle of the optical scanner, is called a resonance frequency. Accordingly, the driving angle reaches a maximum level and the optical scanner can be driven at a high speed when the driving signal corresponds to the resonance frequency
Data Source
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AI summary
A projector and an apparatus and method for driving an optical scanner are disclosed. A sensing signal processor receives a sensing signal that represents sensing of operation of the optical scanner and generates a horizontal scan signal corresponding to a horizontal frequency of the optical scanner on the basis of the received sensing signal. A driving signal generator generates at least one of a horizontal reference signal including line information that indicates the number of horizontal lines of a horizontal driving signal of the optical scanner, a reference clock signal and a scanner driving signal for driving the optical scanner on the basis of the generated horizontal scan signal.