Wide-Angle Zoom Lens Curvature Layout for Ghost Suppression
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Solution Overview
Problem
Wide angle lenses suffer from ghost effects due to unnecessary light reflections, which degrade optical performance, particularly in lenses with large open angles and multiple negative lenses.
Innovation Solution
A zoom lens design with a first lens unit having a negative refractive power, a second lens unit with positive power, and additional lens units, where the refractive index of the negative lens is set to 1.89 or higher, and specific curvature ratios are maintained to minimize ghosting by controlling light reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large lens open angle is used to achieve a wide view angle, then the view angle is improved, but ghost effects occur due to unnecessary light reflections
Solution Approach 1:
The patent converts the harmful reflected light into a beneficial effect by designing the lens curvature ratios to redirect off-axis rays away from the image plane. The specific curvature relationships (Ra/Da ≥ 2.0 and Rb/Db ≥ 10.0) ensure that reflected light is deflected in a controlled manner, transforming the potential ghosting problem into an opportunity to improve optical performance by eliminating unwanted reflections while maintaining the wide view angle.
Solution Approach 2:
The patent applies parameter changes by optimizing the refractive index of the negative lens to 1.89 or higher and establishing specific curvature ratios (Ra/Da ≥ 2.0 and Rb/Db ≥ 10.0). These parameter adjustments control the refraction and reflection characteristics of the lens system, enabling the wide view angle to be achieved while minimizing ghost effects through precise optical parameter optimization.
2Reliability
If multiple negative lenses are added to gently deflect off-axis rays, then optical performance is improved, but the complexity of the lens structure increases
Solution Approach 1:
The patent applies local quality by concentrating the optical correction function in a specific negative lens with optimized properties (refractive index ≥ 1.89 and specific curvature ratios). Rather than distributing complexity across multiple lenses, the invention enhances the local optical quality of a single critical lens element to achieve the desired off-axis ray deflection and ghost effect reduction, thereby improving optical performance while limiting structural complexity.
3Object-generated harmful factors
If the refractive index of the negative lens is increased to 1.89 or higher, then light reflection control is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent uses parameter changes by selecting a specific refractive index threshold (1.89 or higher) for the negative lens material. This parameter optimization enables effective control of light reflection and refraction characteristics. The chosen parameter range balances optical performance requirements with material availability and manufacturing feasibility, achieving superior light reflection control while maintaining practical manufacturability through established optical glass formulations.
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 design reduces ghost images while maintaining high optical performance by gently deflecting off-axis rays, correcting aberrations, and optimizing lens configurations to enhance image quality across a wide zoom range.
Implementation Method 1
The refractive index of a negative lens A disposed on a most object side of negative lenses included in the first lens unit is higher than or equal to 1.89. Where the radius of curvature of an image-side lens surface of the negative lens A is Ra, the radius of curvature of an object-side lens surface of a lens B disposed adjacent to the image side of the negative lens A is Rb
Implementation Method 2
the lens open angle of a first lens is large, and unnecessary light obliquely reflected on an object-side lens surface of a second lens with respect to the lens surface reflects on an image-side lens surface of the first lens and reaches an image plane
Data Source
AI summary
A zoom lens includes a first lens unit having a negative refractive power, a second lens unit having a positive refractive power, and two or more additional lens units. In zooming, the first lens unit moves, and an interval between adjacent lens units changes. The refractive index of a negative lens A disposed on a most object side of negative lenses included in the first lens unit is higher than or equal to 1.89, and the negative lens A and a lens B disposed adjacent to an image side of the negative lens A satisfy a predetermined relationship.