Light Scanning Device Phase Shift Compensation via Beam Bending
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Solution Overview
Problem
Conventional light scanning devices face challenges in accurately compensating for phase shifts in the horizontal scanning direction due to variations in the bending of vertical beams, which affect image quality despite constant temperature.
Innovation Solution
A two-dimensional light scanning device that includes a differential calculation unit to determine the difference in bending of actuating beams over time and a phase shift calculation unit to compensate for phase shifts between drive signals and mirror displacement, improving accuracy in horizontal scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional phase shift compensation techniques are used, then horizontal scanning phase shift is compensated, but accuracy is insufficient due to ignoring beam bending variations
Solution Approach 1:
The patent introduces a feedback mechanism where the actual bending amount of the second actuating beam is measured by a bending amount detection unit, and this measured value is fed back to the phase shift calculation unit to dynamically adjust the phase shift compensation amount, thereby improving compensation accuracy under varying beam bending conditions
Solution Approach 2:
The patent changes the parameter used for phase shift compensation from a fixed or temperature-only based value to a dynamically adjusted value that incorporates real-time beam bending amount measurements, allowing the compensation amount to adapt to actual mechanical variations in the actuating beam
2Temperature
If temperature-based compensation is used, then thermal effects are addressed, but phase shift compensation remains inaccurate due to non-thermal bending variations
Solution Approach 1:
The patent segments the phase shift compensation into two independent components: one based on temperature compensation and another based on beam bending amount compensation, allowing each component to address its specific source of error without interference from the other
Solution Approach 2:
The patent introduces a bending amount detection unit as an intermediary device that specifically measures the mechanical bending of the actuating beam, providing independent data that complements temperature-based compensation and addresses non-thermal sources of phase shift
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
Enhances the accuracy of phase shift compensation in the horizontal scanning direction, reducing image quality degradation such as double vision in projected images.
Implementation Method 1
a second actuating beam (170A, 170B) causing the oscillation of the mirror (110) in the second direction
Implementation Method 2
a differential calculation unit (55) configured to calculate a difference between a bending amount of the second actuating beam (170A, 170B) at a time of an initial drive and a bending amount of the second actuating beam (170A, 170B) after a predetermined period of time
Implementation Method 3
a phase shift calculation unit (56) configured to calculate an amount of phase shift between a driving signal for oscillating the mirror (110) in the first direction and a signal representing a displacement of the mirror (110) in the first direction, based on the difference
Data Source
AI summary
A two-dimensional scan type light scanning device is configured to perform oscillation of a mirror in a first direction and a second direction perpendicular to the first direction. The light scanning device includes a second actuating beam causing the oscillation of the mirror in the second direction, a differential calculation unit configured to calculate a difference between a bending amount of the second actuating beam at a time of an initial drive and a bending amount of the second actuating beam after a predetermined period of time, and a phase shift calculation unit configured to calculate an amount of phase shift between a driving signal for oscillating the mirror in the first direction and a signal representing a displacement of the mirror in the first direction, based on the difference.