Lens Unit Thermal Expansion Compensation
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Solution Overview
Problem
Conventional lens units face challenges in maintaining lens characteristics like resolution due to thermal deformation caused by temperature changes, which affect the distance between the tube lens and the single lens, limiting conjugation length and angle of view.
Innovation Solution
A lens unit comprising a tube lens, a single lens, and a supporting member that includes a board with flange parts in direct contact with protruding parts of the single lens, allowing for thermal expansion and contraction offsetting to maintain a consistent distance and adjust the relative position of the lenses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the tube lens and single lens are supported by a board, then the distance between lenses can be extended, but thermal deformation causes distance extension and contraction leading to degradation of lens characteristics
Solution Approach 1:
The patent applies parameter changes by selecting materials with specific thermal expansion coefficients. The supporting member is made of a material whose thermal expansion coefficient matches or compensates for the combined thermal expansion of the tube lens and single lens, thereby maintaining a stable distance between lenses despite temperature variations. This resolves the contradiction by changing the material parameter to offset thermal deformation effects.
2Length of moving object
If the tube lens and single lens are made to contact directly, then the distance between them cannot be extended, but this limits the conjugation length and angle of view
Solution Approach 1:
The patent introduces a supporting member as an intermediary between the tube lens and single lens. This supporting member provides mechanical support while allowing precise positioning at a predetermined distance, enabling both extended conjugation length and adequate angle of view. The intermediary structure resolves the contradiction by decoupling the mechanical support function from the optical distance requirement.
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 suppresses thermal-induced distance changes between the tube lens and single lens, preventing degradation of lens characteristics such as resolution and allowing for adjustment of the optical path.
Implementation Method 1
the board as well as the lenses would have a thermal deformation caused by changes in temperature and the distance between the tube lens and the single lens would thereby be extended and contracted
Implementation Method 2
Reflection light from a document is condensed on an image sensor by the tube lens and the single lens to form an image
Implementation Method 3
Reflection light from a document is condensed on an image sensor by the tube lens and the single lens to form an image
Data Source
AI summary
A lens unit includes a tube lens; a single lens arranged at a downstream side with respect to the tube lens in an optical incidence direction; and a supporting member that supports the tube lens and the single lens. Reflection light from a document is condensed on an image sensor by the tube lens and the single lens to form an image. An end surface part, not facing the tube lens, of the single lens is in direct contact with the supporting member.