Optical Imaging System With Folded Light Path Prism
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Solution Overview
Problem
High-magnification telephoto cameras in mobile devices face challenges in achieving a slim form factor while maintaining low F values, due to the need for a long focal length which increases the overall camera length.
Innovation Solution
The optical imaging system includes a first lens group, a second lens group, and a prism that converts the path of incident light between the two lens groups, with specific conditional expressions for the diameters, focal lengths, and distances to optimize the system's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a long focal length is used to achieve high-magnification telephoto, then the magnification is improved, but the overall camera length increases
Solution Approach 1:
The patent introduces a light path converting prism that changes the optical path from a linear arrangement to a folded configuration. This allows the light to travel a longer effective distance through multiple lens groups while maintaining a compact physical footprint, thereby achieving high magnification without proportionally increasing the camera module length.
Solution Approach 2:
The patent employs multiple lens groups (first, second, third lens groups) arranged in a nested configuration where each lens group contributes to the overall magnification. The lens groups are positioned to overlap or closely follow each other in the optical path, allowing the system to achieve compound magnification while minimizing the total length of the camera module.
2Adaptability or versatility
If a long focal length is used to achieve high-magnification telephoto, then the magnification is improved, but the F value increases
Solution Approach 1:
The light path converting prism enables the optical system to achieve a longer effective focal length through a folded path rather than a straight line. This separation between effective focal length and physical length allows the system to maintain a low F value (high light gathering capability) while achieving high magnification, as the light can traverse the necessary optical distance without requiring a proportionally long physical aperture.
Solution Approach 2:
The nested arrangement of multiple lens groups allows each group to contribute to both magnification and light gathering. By distributing the optical power across multiple closely-spaced lens groups, the system achieves high magnification while maintaining efficient light transmission, thereby keeping the F value low despite the long effective focal length.
3Illumination intensity
If the diameter of the lens is increased to lower the F value, then the light gathering capability is improved, but the device complexity increases
Solution Approach 1:
Instead of relying on a single large-diameter lens, the patent uses multiple lens groups with smaller individual diameters arranged in a nested configuration. Each lens group has a manageable diameter, but their combined optical effect achieves the same light gathering capability as a single large lens, thereby reducing manufacturing complexity and device complexity while maintaining a low F value.
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 improved low-light imaging performance and miniaturization of the camera module, while maintaining the required focal length and field of view.
Implementation Method 1
a prism disposed between the first lens group and the second lens group, and configured to convert a path of incident light from the first optical axis direction to the second optical axis direction
Data Source
AI summary
An optical imaging system is provided. The optical imaging system includes a first lens group including at least one lens disposed toward a first optical axis; a second lens group including at least one lens disposed in a second optical axis direction perpendicular to the first optical axis direction; and a prism disposed between the first lens group and the second lens group and configured to convert a path of incident light from the first optical axis direction to the second optical axis direction, wherein the conditional expression 0.200≤D1/OAL2≤0.500 is satisfied, wherein D1 is a maximum effective diameter of the first lens group, and OAL2 is a distance on a second optical axis from a reflective surface of the prism to an imaging plane.