Camera Module Variable Aperture Placement for Brightness and Vignetting
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Solution Overview
Problem
Conventional camera modules in mobile terminals suffer from image brightness deterioration and vignetting due to the placement of a variable aperture at the forefront of the lens barrel, making it difficult to achieve high-quality images with a compact structure.
Innovation Solution
A camera module design where a variable aperture is positioned between a first lens group and a second lens group, integrating the aperture with the lenses and an AF driver to adjust light quantity, thereby preventing vignetting and enhancing image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a variable aperture is located at the foremost position of a lens barrel, then the aperture can be integrated with the lens structure, but the brightness of the captured image deteriorates and vignetting occurs
Solution Approach 1:
The variable aperture is extracted from the conventional foremost position and relocated to an intermediate position between the first and second lens groups. This extraction resolves the contradiction by maintaining integration benefits while eliminating the harmful effects on image brightness and vignetting that occur when the aperture is at the frontmost position.
Solution Approach 2:
Instead of placing the aperture at the traditional frontmost position, the invention inverts the arrangement by positioning it between lens groups. This inversion changes the optical path interaction, allowing the aperture to control light quantity without causing severe vignetting or brightness deterioration at the image plane.
2Device complexity
If a variable aperture is located at the foremost position of a lens barrel, then the structure can be simplified, but vignetting of the image occurs
Solution Approach 1:
The variable aperture is extracted from the position that causes vignetting and relocated to an intermediate position between lens groups. This maintains the simplified integrated structure while eliminating the harmful vignetting effect on the image periphery.
3Device complexity
If a single fixed lens barrel is used, then the structure is simple, but it is difficult to compensate for image resolution deterioration and vignetting
Solution Approach 1:
The lens system is segmented into multiple lens groups (first lens group with positive power, second lens group with negative power, and subsequent groups) with the variable aperture positioned between them. This segmentation allows each group to contribute to resolving aberrations and maintaining image resolution while the aperture controls light quantity without causing severe vignetting.
Solution Approach 2:
The invention changes the positional parameter of the variable aperture from the foremost position to an intermediate position between lens groups. This parameter change enables the system to maintain resolution quality and reduce vignetting while still providing variable aperture control functionality.
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 ensures a high-quality, bright image is produced while reducing the size and increasing assembly efficiency of the camera module, effectively addressing the issues of image brightness and vignetting.
Implementation Method 1
a first lens group including a first lens having a positive (+) refractive power and a second lens having a negative (−) refractive power in sequence from an object side
Implementation Method 2
a variable aperture configured to adjust the quantity of light introduced into an optical system
Implementation Method 3
a second lens group including a third lens having a negative (−) refractive power, a fourth lens having a positive (+) refractive power, and a fifth lens having a negative (−) refractive power
Data Source
AI summary
The present invention relates to a camera module mounted in a mobile terminal, comprising: a first lens group having a first lens, which has a positive (+) refractive power, and a second lens, which has a negative (−) refractive power, in order from the object side, wherein the first and second lenses are integrally formed through a first lens barrel; a variable aperture for controlling the quantity of light incident into an optical system; and a second lens group having a third lens having a negative (−) refractive power, a fourth lens having a positive (+) refractive power, and a fifth lens having a positive (+) refractive power, wherein the third to fifth lenses are integrally formed through a second lens barrel.