Varifocal Optical Device Actuator Bending Deformation
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Solution Overview
Problem
Conventional camera modules face challenges in miniaturization and adding functions like auto focusing, optical image stabilization, and zoom due to size restrictions, with existing actuators such as stepping motors, voice coil motors, piezoelectric actuators, and liquid lenses presenting limitations in strain, processing temperature, and liquid filling.
Innovation Solution
A varifocal optical device featuring an actuator unit with two areas that bend in opposite directions when voltage is applied, connected to an optical lens and supported by a unit, allowing for focus adjustment through bending deformation, utilizing dielectric elastomers or ferroelectric polymers, and potentially including bimorph actuators with multiple layers and separate driving mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional actuators (stepping motor, voice coil motor) are used for auto focusing, then the focusing function is achieved, but the camera module size increases and miniaturization becomes difficult
Solution Approach 1:
The patent replaces conventional mechanical actuators (stepping motor, voice coil motor) with a piezoelectric actuator that utilizes piezoelectric effect. This substitution eliminates the need for complex mechanical structures, enabling significant miniaturization of the camera module while maintaining the auto focusing function. The piezoelectric actuator achieves lens positioning through direct coupling of electrical signals to mechanical displacement, removing intermediate mechanical transmission components.
Solution Approach 2:
The patent changes the actuation mechanism from electromagnetic or mechanical systems to piezoelectric systems, fundamentally altering the physical parameter domain. This parameter change enables the actuator to achieve the same focusing function with dramatically reduced size, as piezoelectric materials can produce precise dimensional changes in response to electrical fields without requiring bulky mechanical assemblies.
2Volume of moving object
If piezoelectric actuator is used, then the camera module size is reduced, but the maximum strain is small and processing temperature is high
Solution Approach 1:
The patent employs composite material structures in the piezoelectric actuator design, combining piezoelectric ceramic or polymer materials with flexible substrate materials and electrode layers. This composite approach enhances the overall strain capability of the actuator while managing thermal characteristics. The flexible substrate and electrode configuration help distribute stress and heat, improving both maximum strain and processing temperature performance.
Solution Approach 2:
The patent utilizes thin-film piezoelectric structures and flexible substrate materials to construct the actuator. These thin-film configurations increase the surface area to volume ratio, improving strain output while dissipating heat more effectively. The flexible nature of these thin films also allows for larger deformations without structural failure, addressing the maximum strain limitation.
3Reliability
If liquid lens is used, then the focusing function is achieved, but it is difficult to fill in liquid without generating bubbles
Solution Approach 1:
The patent replaces the liquid lens system with a solid-state piezoelectric actuator system. This substitution eliminates the liquid filling process entirely, removing the manufacturing complexity and quality control issues associated with bubble-free liquid injection. The piezoelectric actuator achieves focusing through solid material deformation, providing a more reliable and manufacturable solution.
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
Enables increased focus adjusting range and potential for miniaturization, simplifying fabrication, and reducing driving voltage, while allowing for improved optical characteristics and functions like zoom and image stabilization within a compact size.
Implementation Method 1
an actuator unit connected with the optical lens and having two areas that are bending-deformed in opposite directions to each other when a voltage is applied thereto
Implementation Method 2
the actuator unit may be formed of a dielectric elastomer, such as an arcrylate or a silicon
Implementation Method 3
the actuator unit may be formed of one of a ferroelectric polymer and a relaxer ferroelectric polymer
Implementation Method 4
the actuator is a layered actuator, which is made up of more than three layers
Implementation Method 5
the actuator unit includes a common ground layer, and first and second electrode layers disposed on both sides of the common ground layer
Data Source
AI summary
A varifocal optical device is provided. The varifocal optical device includes an optical lens, an actuator unit connected with the optical lens and having two areas that are bending-deformed in opposite directions to each other when a voltage is applied thereto, and a supporting unit to support the actuator unit, so that a focus of the optical lens is varied by the bending deformation when the voltage is applied to the actuator unit. Thereby, a driving displacement of the varifocal optical lens can be maximized.