Lens Assembly Thermal Back Focus Compensation Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing lens assemblies in imaging devices face challenges in maintaining image quality due to changes in back focus caused by temperature fluctuations, leading to image blur, especially in compact devices where space for compensation mechanisms is limited.
Innovation Solution
A lens assembly with a lens holder that includes inner, middle, and outer extension and contraction parts linked by respective linking parts, which adjust the position of the lens unit relative to the image sensor to compensate for changes in back focus by extending or contracting in the optical axis direction, allowing for effective compensation without increasing the device's height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extended part having sufficient length is formed to compensate for back focus changes, then image quality deterioration is suppressed, but the overall height of the imaging device becomes higher
Solution Approach 1:
The lens holder is divided into an inner part and an outer part that can relatively move with respect to each other. The inner part includes a first extension and contraction part that extends and contracts in the optical axis direction, while the outer part includes a second extension and contraction part that extends and contracts in the optical axis direction. This segmentation allows the compensation function to be distributed across multiple components rather than requiring a single long extended part, thereby maintaining compact overall height while achieving effective back focus compensation.
Solution Approach 2:
The inner part is disposed inside the outer part, forming a nested structure. The first extension and contraction part and second extension and contraction part are arranged concentrically within the lens holder assembly. This nesting configuration enables both extension and contraction parts to occupy space efficiently without significantly increasing the overall radial or axial dimensions, thus maintaining a low-profile device profile while providing sufficient compensation range.
2Reliability
If the lens holder structure is made more complex to compensate for back focus changes, then image quality is maintained, but device complexity increases
Solution Approach 1:
The inner part and outer part are linked by a linking part that integrates the extension and contraction functionality into a unified structure. The linking part connects the inner part's first extension and contraction part to the outer part's second extension and contraction part, creating a coordinated system where both parts work together to compensate for back focus changes. This merging approach achieves effective compensation while avoiding the need for completely separate compensation mechanisms, thus controlling overall structural complexity.
Solution Approach 2:
The lens holder structure serves multiple functions: it holds the lens unit, provides thermal expansion compensation for back focus changes, and maintains the positional relationship between the lens unit and image sensor. The inner part, outer part, and linking part collectively provide both structural support and compensation functionality, eliminating the need for additional separate compensation components and thereby controlling device complexity.
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 secures the necessary extension and contraction amounts to maintain image quality across varying temperatures while maintaining a low-profile design, ensuring the lens unit remains aligned with the image sensor, thus preventing image blur.
Implementation Method 1
an inner extension and contraction part for extending and contracting in the direction of the optical axis of the lens unit associated with a change in atmospheric temperature is provided between an attachment location of the linking part on the inner part and an attachment location of the lens unit, and an outer extension and contraction part for extending and contracting in the direction of the optical axis of the lens unit associated with a change in atmospheric temperature is provided between an attachment location of the linking part on the outer part and the reference surface
Data Source
AI summary
A lens assembly and an imaging device for realizing low-profileness, and for effectively compensating a change in back focus generated by a change in atmospheric temperature. A lens holder contained in a lens assembly of an imaging device includes an inner frame on which a lens unit is attached, a holding frame provided with a lower end surface fixing a positional relationship with an image sensor, a linking frame for linking the inner frame and the holding frame. The lens holder extends and contracts so that the inner frame and the holding frame distance the lens unit from the image sensor when back focus of the lens unit extends due to change in atmospheric temperature, and brings the lens unit closer to the image sensor when the back focus contracts.