Under-Display Camera Module With Sensor-Shift Autofocus
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Solution Overview
Problem
Conventional camera modules using voice coil motor (VCM) technology face challenges in performing autofocus operations smoothly, especially when the amount of light is reduced by a display module, such as in smartphones.
Innovation Solution
The camera module includes a lens fixedly disposed apart from the display panel, an image sensor spaced apart from the lens, and a driving unit to move the image sensor along the optical axis, ensuring a constant light introduction and maintaining autofocus functionality even with reduced light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the camera module is disposed under the display panel, then the device integration is improved, but the amount of light reaching the image sensor is reduced
Solution Approach 1:
Instead of moving the lens to perform autofocus (conventional approach), this patent inverts the approach by moving the image sensor while keeping the lens fixed. This allows the camera module to be disposed under the display panel with the lens facing upward through the display, ensuring adequate light reaches the image sensor while maintaining autofocus capability.
Solution Approach 2:
The patent changes the autofocus mechanism from lateral lens movement to longitudinal image sensor movement along the optical axis. This dimensional change allows the camera module to maintain proper optical path alignment while being positioned under the display panel, resolving the light intensity issue.
2Ease of operation
If the lens is moved for autofocus, then the autofocus function is achieved, but the light amount becomes insufficient when disposed under display panel
Solution Approach 1:
The patent inverts the conventional autofocus mechanism by keeping the lens fixed and moving the image sensor instead. This allows the lens to be positioned optimally for light collection while the image sensor moves to achieve focus, resolving the light insufficiency problem.
Solution Approach 2:
The driving unit is designed to move the image sensor assembly, which includes both the image sensor and the lens holder in some embodiments, providing a universal solution that can accommodate different optical configurations while maintaining autofocus functionality under the display panel.
3Ease of operation
If the image sensor is moved in optical-axis direction, then the autofocus operation is smooth, but the device complexity increases
Solution Approach 1:
The patent merges the image sensor, holder, and driving unit into an integrated assembly that moves together as a single unit. This combining of components simplifies the overall structure compared to moving the lens separately, reducing device complexity while maintaining smooth autofocus operation.
Solution Approach 2:
The patent replaces complex mechanical lens driving mechanisms with a simpler electromagnetic driving unit that directly moves the image sensor assembly. This substitution reduces mechanical complexity while achieving smooth autofocus operation through direct electromagnetic actuation.
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 smooth autofocus operation without insufficiency in light, maintaining image quality and preventing resolution deterioration, even when light is reduced by the display module.
Implementation Method 1
The camera module may include a filter coupled to the holder and a support member conductively connecting the first circuit board to the second circuit board and supporting the image sensor so that the image sensor is movable. The first circuit board and the image sensor may be moved in the optical-axis direction due to interaction between the coil and the magnet.
Data Source
AI summary
An embodiment comprises: a display panel including an active area; and a camera module for receiving light passing through the active area, wherein the camera module includes: a lens fixed to be spaced apart from the display panel; an image sensor spaced apart from the lens; and a driving unit for moving the image sensor in an optical axis direction.