Afocal Accessory Lens Structures for Loose Mounting Tolerances
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Solution Overview
Problem
Existing camera lens systems with removable accessory lenses face challenges in maintaining high image quality while allowing for easy attachment and detachment due to tight mechanical alignment tolerances, leading to increased costs and complexity.
Innovation Solution
Designing accessory lens assemblies with afocal configurations and oversized exit pupils to overfill the entrance pupils of the mother lens, enabling loose mounting tolerances and temperature-insensitive image quality, along with mechanisms like bayonet mounts for easy attachment and detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tight mechanical alignment tolerances are used to maintain high image quality, then image quality is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the optical parameters of the accessory lens assembly by designing an afocal configuration with a specific exit pupil size. This parameter change allows the system to tolerate mechanical alignment variations while maintaining image quality, thereby reducing manufacturing complexity without sacrificing optical performance
Solution Approach 2:
The patent applies beforehand cushioning by designing the optical system with built-in tolerance compensation. The afocal configuration and oversized exit pupil create a buffer that absorbs mechanical alignment errors before they can affect image quality, allowing looser manufacturing tolerances
2Reliability
If tight mechanical alignment tolerances are used to maintain high image quality, then image quality is improved, but attachment and detachment become more difficult
Solution Approach 1:
The patent changes the optical parameters to create a more robust system that tolerates mechanical variations. The afocal design with oversized exit pupil allows users to attach and detach lenses easily without requiring precise alignment, maintaining image quality while improving ease of operation
Solution Approach 2:
The optical design provides self-alignment capabilities where the oversized exit pupil and afocal configuration automatically compensate for misalignment during attachment, eliminating the need for user precision and simplifying the attachment process
3Manufacturing precision
If exit pupil is sized to overfill entrance pupil by amount exceeding mounting and manufacturing tolerances, then mounting tolerance is relaxed, but lens assembly size increases
Solution Approach 1:
The patent applies parameter changes by designing the exit pupil to be larger than the entrance pupil by a specific amount that exceeds expected mounting and manufacturing tolerances. This parameter relationship (exit pupil > entrance pupil) creates a tolerance buffer that relaxes mounting precision requirements while the afocal configuration helps control the overall size increase
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
Facilitates easy and cost-effective attachment of accessory lenses without compromising image quality, providing wider field of view and smaller magnification, reducing manufacturing complexity and costs.
Implementation Method 1
light incident on an outer lens of the second stack of lenses will be refracted through the second stack of lenses and the first stack of lenses to the image sensor
Implementation Method 2
the second stack of lenses is afocal
Data Source
AI summary
An image capture device can include a mother lens assembly including a lens stack; an image sensor positioned at a first end of the mother lens assembly and configured to detect images based on light incident on the image sensor through the lens stack; a conversion lens assembly including an outer lens, and a conversion lens mounting apparatus configured to removably attach the conversion lens assembly to the image capture device in a position over a second end of the mother lens assembly, opposite from the image sensor, such that light incident on the conversion lens assembly will be refracted through the outer lens and the lens stack of the mother lens assembly to the image sensor. The lens stack and the outer lens combined can have a smaller magnification than that of the lens stack alone.