Zoom Lens System Compactness via Four-Unit Configuration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional zoom lens systems for compact digital cameras face challenges in achieving a high zooming ratio while maintaining a compact size, as increasing the number of lenses leads to increased size and thickness, making it difficult to achieve a sufficiently compact lens barrel even in the collapsed state.
Innovation Solution
A four-unit zoom lens system with a specific configuration, including a first lens unit with positive refracting power, a second lens unit with negative refracting power, a third lens unit with positive refracting power, and a fourth lens unit with positive refracting power, where at least the first, second, and third lens units move during zooming, and the second lens unit has no more than three lenses, satisfying certain conditional expressions to control lateral magnifications and focal lengths, thereby optimizing the zooming ratio and compactness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of lenses in the first lens unit and second lens unit is increased to secure edge thickness, then the edge thickness is sufficient, but the longitudinal thickness and radial size increase remarkably
Solution Approach 1:
The patent changes the parameters of the first lens unit by introducing a negative lens with specific refractive index and curvature radius, and adjusting the air gap between lenses. This allows securing sufficient edge thickness while controlling the longitudinal thickness through optimized optical parameters rather than simply increasing the number of lenses.
Solution Approach 2:
The first lens unit uses a composite structure combining a positive lens and a negative lens with specific refractive indices. This composite approach enables better control over light paths and ray heights, allowing sufficient edge thickness without proportionally increasing longitudinal thickness.
2Manufacturing precision
If the number of lenses in the first lens unit and second lens unit is increased, then the edge thickness is secured, but the radial size and collapsed lens barrel size increase
Solution Approach 1:
The patent optimizes parameters such as the refractive index of the negative lens (1.7-1.9), the curvature radius of the first lens surface (50-200mm), and the air gap between lenses to achieve sufficient edge thickness while minimizing the radial size and collapsed lens barrel volume.
Solution Approach 2:
The patent addresses the edge thickness requirement not by increasing radial dimensions or number of lenses, but by optimizing the longitudinal arrangement and optical path in the third dimension, allowing sufficient edge thickness with a compact collapsed structure.
3Manufacturing precision
If the entrance-pupil position is moved distant from the object side to increase off-axis ray height, then the edge thickness is secured, but the longitudinal thickness required for edge thickness increases
Solution Approach 1:
The patent changes the optical parameters including the refractive index of the negative lens and the air gap distance to control the off-axis ray height and entrance-pupil position relationship. This allows securing edge thickness while preventing excessive longitudinal thickness 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
This configuration allows for a high zooming ratio while preventing excessive size increase and aberration, enabling a more compact lens barrel by efficiently distributing the load of zooming across the lens units and reducing the number of lens barrels, thus achieving a balance between zooming capability and size reduction.
Implementation Method 1
a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a positive refracting power
Data Source
AI summary
A four-unit zoom lens system includes in order from an object side, a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a positive refracting power, in which at a time of zooming from a wide angle end to a telephoto end, at least the first lens unit, the second lens unit, and the third lens unit move, and a space between the lens units changes, and a total number of lenses in the second lens unit is not more than three, and the zoom lens system satisfies the following conditional expressions.1.2<(β2t/β2w)/(β3t/β3w)<6.0 and (1A)3.0<ft/fw<20.0 (2A)