Folded Optical Path Camera Module for Compact Telephoto Imaging
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Solution Overview
Problem
Existing optical systems in portable electronic devices face challenges in achieving telephoto characteristics while maintaining a compact form factor due to the direct proportional relationship between effective focal length and optical path length, which limits their application in miniaturized devices.
Innovation Solution
An optical system design incorporating a first lens with positive refractive power and a reflective element that changes the optical axis, allowing the first element group to rotate around a parallel axis while keeping the image plane fixed, combined with a movable second element group for focusing, to achieve anti-shaking functionality with reduced complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the effective focal length of the optical system is increased to achieve telephoto characteristics, then the imaging quality of distant objects is improved, but the optical path length and total system length increase, limiting application in portable devices
Solution Approach 1:
The patent introduces a reflective element that folds the optical path, changing the optical axis direction. This allows the light to travel a longer effective focal length distance while the physical system length remains compact, resolving the contradiction between telephoto imaging quality and portable device size constraints
2Length of moving object
If a reflective element is added to fold the optical path and reduce system length, then the total system length is reduced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The first element group serves dual functions: it focuses light for imaging and acts as the rotating anti-shaking unit. The reflective element is integrated into this multi-functional design, reducing the need for separate anti-shaking mechanisms and thereby limiting the increase in device complexity despite adding the reflective component
3Reliability
If optical anti-shaking functionality is implemented by rotating element groups, then imaging stability is improved, but the device complexity and cost increase
Solution Approach 1:
The patent merges the anti-shaking function with the existing first element group that already contains the reflective element. By rotating this combined group around an axis parallel to the optical axis, the patent achieves optical anti-shaking without requiring a separate, complex anti-shaking mechanism, thus improving imaging stability while limiting the increase in device complexity and cost
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 achieves low-cost optical anti-shaking with good imaging quality, miniaturization, and increased aperture, while maintaining imaging quality by rotating the first element group around a parallel axis without shifting the image plane, thus reducing the total system length and weight.
Implementation Method 1
The reflective element changes light rays emitted from the first lens from propagating along a first optical axis to propagating along a second optical axis
Implementation Method 2
The first lens has a positive refractive power, and allows propagation of light rays along a first optical axis
Data Source
AI summary
Disclosed are an optical system and a camera module. The optical system sequentially includes, from an object side to an image side, a first lens, a reflective element and a second element group. The first lens has a positive refractive power, and allows propagation of light rays along a first optical axis. The reflective element changes light rays emitted from the first lens from propagating along the first optical axis to propagating along a second optical axis. The first lens and the reflective element constitute a first element group. The second element group has a positive refractive power. During an anti-shaking process, the position of an image plane of the optical system remains fixed, and the first element group rotates around a direction parallel to the second optical axis, an effective focal length f1 of the first lens and an effective focal length EFL of the optical system satisfy: 1.9<|f1/EFL|<3.0.