Light Blocking Sheet Inner Surface Geometry for Stray Light Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional light blocking sheets in imaging lens assemblies suffer from unwanted residual light and stray light reflections due to their hole inner surfaces, which degrade image quality.
Innovation Solution
A light blocking sheet with a central axis and inner extended portions having specific geometric structures, including line pairs and arc sections, that reduce stray light reflections by properly diverging intense light spots and minimizing unwanted residual light around the image.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional light blocking sheet with a circular hole inner surface is used, then the structure is simple and easy to manufacture, but unwanted residual light and stray light reflections occur around the image, degrading image quality
Solution Approach 1:
The hole inner surface is segmented into multiple sections (first hole inner surface section, second hole inner surface section, third hole inner surface section) with different geometric configurations. Each section serves a specific function in controlling light paths, thereby reducing stray light reflections while maintaining manufacturing feasibility through systematic division of the surface geometry
Solution Approach 2:
Different sections of the hole inner surface are given different local geometric properties. The first section has a specific curvature radius relationship (R1 < 0.5×D1) to control light reflection angles, the second section provides transition geometry, and the third section completes the light control pathway. This local differentiation optimizes light control at each zone while maintaining overall structural integrity
2Object-affected harmful factors
If the hole inner surface geometry is optimized to reduce stray light, then image quality improves, but the geometric structure becomes more complex and manufacturing difficulty increases
Solution Approach 1:
The hole inner surface incorporates curved geometric sections with specifically defined curvature radii. The first hole inner surface section has a curvature radius R1 satisfying R1 < 0.5×D1, creating controlled light reflection angles that reduce stray light. These curved surfaces provide smooth light path transitions while maintaining manufacturability through defined geometric parameters
Solution Approach 2:
The solution transitions from a two-dimensional planar hole surface to a three-dimensional curved surface geometry. By introducing depth variations and curvature in the hole inner surface, the patent creates multiple light reflection planes that redirect stray light away from the image area, adding a spatial dimension to light control without excessive complexity
3Device complexity
If intense light spots are not properly diverged, then the light blocking sheet structure remains simple, but unwanted residual light appears around the image, reducing imaging performance
Solution Approach 1:
The light blocking sheet performs preliminary light path control by strategically positioning and shaping the hole inner surface sections before light reaches the image sensor. The curved surfaces pre-diverge intense light spots and redirect potential stray light paths, preventing residual light formation at the image plane in advance, thereby improving imaging performance proactively
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 proposed light blocking sheet design effectively reduces stray light reflections and enhances image quality by optimizing the geometric structures of its inner surfaces, improving manufacturing yield and imaging performance under various light conditions.
Implementation Method 1
The reflected light from the hole inner surface 92 usually results in the unwanted residual light around the image, and thereby the stray light reflection becomes more intense to affect the image quality
Data Source
AI summary
A light blocking sheet having a central axis includes a central hole and a plurality of inner extended portions. The central axis passes through the central hole, which is enclosed by a hole inner surface. The hole inner surface has a first corresponding circle and a second corresponding circle, wherein a diameter of the first corresponding circle is greater than a diameter of the second corresponding circle. The inner extended portions are adjacent to and surround the central hole, wherein each of the inner extended portions is extended and tapered from the first corresponding circle towards the second corresponding circle and includes an inner surface, and the inner surface includes a line pair. The line pair includes two line sections, wherein one end of one line section thereof and one end of the other line section thereof are towards the second corresponding circle and approach to each other.