Multibeam Scanning Device Optical Path Shifting
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Solution Overview
Problem
Multibeam scanning devices that do not converge laser beams on the deflection surface face challenges in adjusting beam spot positions without causing vignetting or performance deterioration, as existing mechanisms require large deflectors or significant shifts in incident positions.
Innovation Solution
A multibeam scanning device design that includes a plurality of first optical systems with light sources emitting non-collimated beams, a deflector for beam deflection, and an optical path shifting system to adjust the incident angle without changing the position on the deflector, allowing collimated or diverging beams to be incident on the deflector at the same position, thereby stabilizing spot positions and reducing deflector thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the incident angle of laser beams with respect to the deflector is changed to adjust beam spot positions, then the beam spot positions can be adjusted, but the incident positions on the deflector change significantly causing vignetting and performance deterioration
Solution Approach 1:
The patent introduces a new degree of freedom by tilting the entire deflector assembly around an axis perpendicular to the main scanning direction. This allows beam spot position adjustment in the auxiliary scanning direction without changing the incident angle in the main scanning plane, thereby preventing vignetting and maintaining deflector performance while achieving precise beam spot positioning.
Solution Approach 2:
The deflector assembly is designed to perform multiple functions simultaneously: it maintains the primary beam deflection function while the added tilting capability provides beam spot position adjustment. This multi-functionality allows a single component to handle both beam steering and spot positioning without requiring separate adjustment mechanisms.
2Manufacturing precision
If a large deflector is used to accommodate significant shifts in incident positions, then beam spot adjustment is possible, but the device size and complexity increase
Solution Approach 1:
Instead of increasing deflector size to accommodate incident position shifts, the patent uses a tilting mechanism that operates in a different dimensional space. By rotating the deflector around a tilt axis, the system achieves beam spot position adjustment without requiring a larger deflector aperture, thus maintaining compact device dimensions while providing full adjustment capability.
3Reliability
If beams are converged on the deflection surface, then the deflection surface and scanned surface become conjugate, but the image height remains constant regardless of incident angle making it unsuitable for scanning
Solution Approach 1:
The patent resolves the conflict between beam convergence stability and scanning adaptability by introducing a tilt degree of freedom. The deflector can maintain its primary optical configuration for stable beam deflection while the additional tilting capability enables scanning functionality by adjusting beam spot positions without affecting the conjugate relationship between deflection and scanned surfaces.
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 allows for stable adjustment of beam spots on the scanning surface without vignetting, achieving a compact and efficient scanning system by maintaining consistent incident positions on the deflector, even when changing incident angles.
Implementation Method 1
an optical element having a predetermined power and having an optical effect on the laser beam
Data Source
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AI summary
A multibeam scanning device, comprising: a plurality of first optical systems, each of the plurality of optical systems including a light source unit configured to emit a non-collimated light beam, and an optical element having a predetermined power and having an optical effect on the laser beam; a second optical system arranged on a downstream side of the plurality of first optical systems, including a first deflector on which light beams emitted by the plurality of first optical systems are incident, the first deflector being to deflect the laser beams, and a common optical system configured to change degree of divergence of each of the plurality of light beams; and an optical path shifting system configured to translate an incident optical path of the light beam which is emitted by the light source and incident on the optical element, wherein all the light beams incident on the first deflector are incident on the first deflector at substantially the same position, and wherein the optical elements are arranged such that optical axes of the optical elements intersect at a position spaced from the optical element by a distance equal to a focal length of the optical element.