Zoom Lens System With Reflective Optical Element for Compact Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional zoom lens systems for digital cameras face challenges in achieving a high magnification variation ratio of 5× or greater while maintaining a compact and thin design, with existing solutions often requiring complex mechanisms and large reflecting surfaces, which can limit thickness reduction and optical performance.
Innovation Solution
A zoom lens system comprising a first lens unit with positive optical power, a second lens unit with a reflective optical element having negative power, and subsequent lens units, where the reflective optical element is positioned differently in the accommodated and imaging states, optimizing focal length ratios and air space usage to achieve a compact and high-resolution design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If a right-angle prism is arranged inside a lens unit to bend light by 90°, then the thickness of the imaging device is reduced, but the device complexity increases due to additional optical elements and precise positioning requirements
Solution Approach 1:
The patent embeds the right-angle prism inside the second lens unit, nesting the reflective optical element within the existing lens structure. This allows the prism to be integrated into the optical path without requiring separate housing or mounting mechanisms, thereby reducing overall device thickness while avoiding excessive complexity increase through clever spatial arrangement
Solution Approach 2:
The patent utilizes the internal space of the second lens unit in a different dimensional arrangement by placing the prism at specific positions (object side or image side) within the lens unit. This dimensional reorganization allows light bending to occur within the existing optical path volume, achieving thickness reduction without proportionally increasing device complexity
2Reliability
If multiple lens units are used to achieve a magnification variation ratio exceeding 3×, then the optical performance is improved, but the mechanism becomes complicated and the merit of thickness reduction becomes small
Solution Approach 1:
The patent merges the function of the right-angle prism with the second lens unit by integrating the reflective element within the lens unit structure. This combination allows the second lens unit to serve dual purposes: maintaining its zooming function while also providing the platform for light bending, thereby reducing mechanism complexity even with multiple lens units for high magnification variation
Solution Approach 2:
The second lens unit is designed to serve multiple functions: it participates in the zooming mechanism (providing negative optical power for focal length adjustment) and simultaneously houses the right-angle prism for light direction control. This multi-functionality reduces the need for separate dedicated components, thereby maintaining optical performance with reduced mechanism complexity
3Length of stationary object
If a specific optical element is solely escaped to reduce thickness, then the retraction is achieved, but the thickness is determined by non-escaped optical elements so the thickness reduction is limited
Solution Approach 1:
The patent extracts the right-angle prism from the main optical path in the retracted state by positioning it within the second lens unit that can be moved or reconfigured. This extraction allows the prism to be removed from the thickness-critical path during retraction, enabling more effective thickness reduction beyond what would be achieved by retracting a single optical element alone
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 solution enables a zoom lens system with a magnification variation ratio of 5× or greater, achieving a compact and thin design with improved optical performance and reduced complexity, allowing for a thinner camera body while maintaining high resolution.
Implementation Method 1
a second lens unit having negative optical power and including a reflective optical element with a reflecting surface for bending a light ray from an object by 90°
Data Source
AI summary
A zoom lens system, in order from the object side to the image side, comprises: a first lens unit having positive optical power; a second lens unit that includes a reflective optical element having a reflecting surface for bending object light and that has negative optical power; and a subsequent lens unit including more than one lens unit having positive optical power, and that satisfies the condition: −5.70<f1/f2<−2.00 (Z=fT/fW>5.0, f1 is the composite focal length of the first lens unit, f2 is the composite focal length of the second lens unit, fW is the focal length of the entire zoom lens system at a wide-angle limit, fT is the focal length of the entire zoom lens system at a telephoto limit, Z is the magnification variation ratio), and is held in a compact lens barrel.