Variable Thickness Stop Blades for Aperture Load Reduction
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Solution Overview
Problem
Conventional light-quantity control apparatuses with multiple stop blades face excessive load and warping issues due to overlapping blades, leading to increased size and potential optical performance degradation.
Innovation Solution
The design features light-quantity control blades with a thin portion that decreases in thickness towards the inner edge, reducing reaction forces and allowing for smoother operation and reduced interference, enabling the blades to be housed closer to lenses and downsizing the optical apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If multiple stop blades are used to form a circular aperture, then the shape of the stop aperture is improved, but the load generated by overlapping blades becomes excessively large
Solution Approach 1:
The patent applies local quality by making the thickness of stop blades non-uniform. Specifically, the blades have a thinner section at the overlapping region compared to other parts. This localized thickness reduction decreases the reaction force at the overlapping portion, thereby reducing the overall load while maintaining the circular aperture shape formed by multiple blades
2Shape
If multiple stop blades with overlapping are used, then the stop aperture can be formed, but warping of blades occurs leading to optical performance degradation
Solution Approach 1:
The patent implements local quality by varying the thickness of stop blades along their length. The blades are designed with a thinner section at the overlapping region, which reduces the reaction force and consequently minimizes warping in that critical area. This localized thickness modification maintains blade stability while still forming the required stop aperture shape
3Volume of moving object
If stop blades are positioned closer to lenses to downsize the apparatus, then the optical apparatus size is reduced, but blade scratching and diffraction may occur
Solution Approach 1:
The patent applies local quality by creating a thinner section of the stop blade at the overlapping region. This thinner portion reduces the reaction force and minimizes warping, which in turn reduces the risk of blade scratching when positioned close to lenses. The reduced blade warping also helps prevent diffraction, allowing the apparatus to be downsized without compromising optical performance
Data Source
AI summary
A light-quantity control apparatus includes multiple light-quantity control blades each configured to overlap with at least another one of the light-quantity control blades so as to form a light-passing aperture and each configured to rotate to change a size of the light-passing aperture. Each of the multiple light-quantity control blades includes a thick portion and a thin portion. The thick portion forms an outer end portion on an opposite side to the light-passing aperture in a rotation direction of the light-quantity control blade. The thin portion is formed in an aperture side blade area that overlaps with the at least another one of the multiple light-quantity control blades so as to form part of a circular overlap of the multiple light-quantity control blades and that includes an inner edge forming an edge of the light-passing aperture.