Optical Filter Holding Mechanism for Thin Camera Lens Barrel
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Solution Overview
Problem
Conventional mechanisms for holding optical elements in camera lens barrels increase the thickness of the optical axis direction, leading to ghost images due to direct mounting of optical filters, which affects the overall thickness and collapsibility of the optical system.
Innovation Solution
An electronic image pickup apparatus with a first holding member having a base portion parallel to the optical axis and extended portions perpendicular to it, holding the optical filter in a way that its subject side surface is at the same level as the second holding member, reducing the optical axis length and thickness, and using a thin metallic member for improved fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the optical filter is directly mounted on the second holding member, then the optical filter is securely held, but the thickness of the optical unit in the optical axis direction increases
Solution Approach 1:
The first holding member extends in the radial direction (perpendicular to optical axis) to provide holding function, while the second holding member maintains the optical filter position. This dimensional redistribution allows the optical filter to be held securely without increasing thickness in the optical axis direction.
Solution Approach 2:
The first holding member is positioned between the optical filter and the second holding member, creating a nested structure where multiple holding functions are integrated in a compact arrangement. This nesting reduces the overall thickness while maintaining secure holding.
2Length of moving object
If a conventional holding mechanism with holding part is used, then the optical filter is firmly fixed, but the overall length of the optical system in the optical axis direction increases
Solution Approach 1:
The holding function is segmented into two separate holding members: the first holding member provides primary holding and positioning, while the second holding member provides secondary support and alignment. This segmentation allows each component to be optimized for its specific function with minimal thickness.
Solution Approach 2:
The first holding member is designed as a thin plate-like structure that provides sufficient mechanical support and holding capability while minimizing thickness. The thin film structure maintains fixation firmness without adding significant length to the optical system.
3Object-affected harmful factors
If the optical filter is mounted with a holding part of non-zero thickness, then the optical filter is securely positioned, but ghost images are generated
Solution Approach 1:
The holding part with significant thickness is extracted and replaced by thin plate-like first and second holding members. This extraction eliminates the source of ghost images while maintaining positioning accuracy through the coordinated action of the two thin holding members.
Solution Approach 2:
The thickness parameter of the holding structure is changed from conventional non-zero thickness to minimal thin-plate thickness. This parameter change reduces light reflection and refraction at multiple interfaces, thereby minimizing ghost image generation while maintaining adequate positioning accuracy.
Data Source
AI summary
In an electronic image pickup apparatus of the present invention, a lens barrel having optical elements arranged in the optical axis direction has a CCD for photographing a luminous flux from a subject, a CCD holder formed around the CCD to hold the CCD, and a low-pass filter provided on the front side of the CCD. A low-pass filter holder as a plate-like member to hold and fix the low-pass filter is provided to contact the low-pass filter at one end through a diaphragm on the CCD side surface, and contacts the CCD holder on the side opposite to the CCD at the other end.