Image Reading Lens Thermal Correction Mechanism
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Solution Overview
Problem
Existing image reading lenses fail to correct field curvatures and image-forming positions accurately due to temperature changes, leading to performance deterioration caused by material expansion and refractive index variations.
Innovation Solution
An image reading lens with a first correcting mechanism for field curvature and a second correcting mechanism for image-forming position, utilizing two holding members with different linear expansion coefficients to adjust lens intervals and maintain image quality across temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single correcting mechanism is used to adjust image-forming position, then image-forming position accuracy is improved, but field curvature correction is insufficient
Solution Approach 1:
The patent divides the correcting mechanism into two independent parts: a first correcting mechanism for field curvature correction and a second correcting mechanism for image-forming position correction. This segmentation allows each mechanism to specialize in one function, achieving both field curvature and position accuracy simultaneously without interference between the two correction tasks.
Solution Approach 2:
The patent introduces different degrees of freedom for the two correcting mechanisms. The first correcting mechanism adjusts field curvature through one degree of freedom, while the second correcting mechanism adjusts image-forming position through another degree of freedom. This dimensional separation enables independent optimization of both correction functions.
2Ease of manufacture
If holding members with same linear expansion coefficient are used, then manufacturing is simplified, but temperature-induced distortion cannot be corrected
Solution Approach 1:
The patent changes the material parameter (linear expansion coefficient) of the holding members to different values. The first holding member has a first linear expansion coefficient while the second holding member has a second linear expansion coefficient different from the first. This parameter differentiation enables the structure to compensate for temperature-induced distortions through differential expansion, improving temperature stability.
Solution Approach 2:
The patent employs composite material selection for the holding members, choosing materials with specifically different linear expansion coefficients. This composite approach allows the holding member assembly to function as a temperature-compensating structure, where the differential thermal expansion between the two holding members counteracts temperature-induced optical path changes.
3Device complexity
If lens interval is fixed, then structural simplicity is maintained, but temperature-induced image-forming position shift cannot be corrected
Solution Approach 1:
The patent transforms the fixed lens interval structure into a dynamic, adjustable structure. The second correcting mechanism enables the lens interval to change in response to temperature variations, allowing the system to maintain accurate image-forming position despite thermal expansion or contraction of the lens barrel. This dynamic adjustment capability corrects temperature-induced position shifts.
Solution Approach 2:
The patent utilizes thermal expansion principles in the design of the holding members with different linear expansion coefficients. By strategically selecting materials and configuring the holding member assembly, the system leverages differential thermal expansion to compensate for temperature-induced changes in lens interval and image-forming position, converting a potential source of error into a correction mechanism.
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
The solution effectively corrects field curvatures and image-forming positions, ensuring high-quality image acquisition even with temperature fluctuations, thereby enhancing the performance and accuracy of image reading devices.
Implementation Method 1
utilizing two holding members with different linear expansion coefficients to adjust lens intervals and maintain image quality across temperature changes
Implementation Method 2
configured to form reduced optical images using image reading lenses
Data Source
AI summary
An image reading lens includes a plurality of lenses, a first correcting mechanism that corrects a field curvature at a first correction part when temperature changes, and a second correcting mechanism that corrects an image-forming position when the temperature changes. The second correcting mechanism corrects the image-forming position at a part where a positional displacement of the image-forming position caused by a change of a lens interval is greater and a variation of the field curvature caused by the change of the lens interval is smaller than the first correction part.