Optical Scanning Lens Sag Reduction via Overlapping Surfaces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional optical scanning apparatuses face issues with sag in the optical axis direction at discontinuous parts between optical functional portions, leading to deterioration of optical capabilities due to misalignment of light fluxes with different oblique incident angles, which affects the quality of images formed.
Innovation Solution
The optical scanning apparatus incorporates a deflection unit and multiple incident optical systems that cause light fluxes to enter at different angles, with the imaging optical system featuring first and second optical functional portions connected by a connecting portion where their incident or exit surfaces overlap, reducing sag and maintaining optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If optical functional portions are arranged side by side in the sub-scanning direction with different oblique incident angles, then the imaging lens can handle multiple light fluxes, but sag occurs at the discontinuous parts causing deterioration of optical capabilities
Solution Approach 1:
The patent applies local quality by designing different surface curvatures for different regions of the optical functional portions. Specifically, the first and second optical functional portions have different curvatures in the sub-scanning direction to accommodate light fluxes with different oblique incident angles. This localized differentiation allows each region to optimize its optical performance for its specific incident angle while maintaining overall system versatility.
Solution Approach 2:
The imaging lens is segmented into multiple optical functional portions (first and second optical functional portions) arranged side by side in the sub-scanning direction. Each portion is designed with specific curvature characteristics suited to its function of handling light fluxes with particular oblique incident angles. This segmentation allows the system to handle multiple light flux types while managing the complexity of sag at discontinuous parts through localized design optimizations.
2Manufacturing precision
If the incident surfaces and exit surfaces of optical functional portions are smoothly connected by a spline curve surface, then sag in the optical axis direction is eliminated, but the optically effective area decreases and required imaging properties cannot be achieved
Solution Approach 1:
The patent applies local quality by providing different curvatures in the sub-scanning direction for the first and second optical functional portions. This localized curvature differentiation allows each portion to maintain its optimal optical characteristics and effective area while the connecting portion is designed to minimize sag. The spline curve connection is used selectively to maintain smooth transitions where needed without compromising the optically effective areas of the functional portions themselves.
3Device complexity
If a common imaging lens is shared among multiple photosensitive drums, then the number of components is reduced and size is minimized, but optical functional portions must be designed for specific incident angles causing sag at boundaries
Solution Approach 1:
The patent applies universality by designing a common imaging lens with multiple optical functional portions that can handle light fluxes from multiple photosensitive drums with different oblique incident angles. The first and second optical functional portions are configured with different curvatures to accommodate different incident angle ranges, enabling a single lens system to serve multiple drums while managing the optical challenges at boundaries through localized curvature optimization.
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 ensures high-quality image formation without deteriorating optical capabilities by minimizing sag at the connecting portion between optical functional portions, enhancing the transferability and imaging properties of the optical scanning apparatus.
Implementation Method 1
a deflection unit that deflects a light flux
Implementation Method 2
a deflection unit that deflects a light flux
Implementation Method 3
an imaging optical system that guides a plurality of light fluxes deflected by the deflection unit onto a scanned surface
Data Source
AI summary
The optical scanning apparatus according to the present invention includes a deflection unit that deflects a light flux, a plurality of incident optical systems that cause light fluxes to enter the deflection unit at different incident angles in a sub-scanning cross section, and an imaging optical system that guides a plurality of light fluxes deflected by the deflection unit onto a scanned surface. The imaging optical system has a first optical functional portion and a second optical functional portion arranged in a sub-scanning direction and connected to each other by a connecting portion. In a plane including the connecting portion, at least incident surfaces or exit surfaces of the first and second optical functional portions overlap with each other at least at one point.