Liquid Lens Curvature Control via Capacitance Sensing
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Solution Overview
Problem
Existing lens systems in small electronic devices face challenges in adjusting focus without physically moving the lens, requiring significant space and being unsuitable for optical image stabilization in two or three dimensions.
Innovation Solution
A lens curvature variation apparatus that uses a liquid lens driven by an electrical signal, incorporating a lens driver, sensor unit, and controller to accurately sense and adjust the curvature of the liquid lens, allowing for focus adjustment without physical movement and enabling optical image stabilization in multiple dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the position of the lens is varied to adjust focus, then the focus adjustment is achieved, but the device requires considerable space which is inconvenient for small electronic devices
Solution Approach 1:
The patent replaces the mechanical lens movement system with an electric field-based liquid lens curvature control system. By applying voltage to the liquid lens, the curvature is adjusted electronically without any mechanical moving parts, thereby eliminating the space requirements for mechanical focus adjustment mechanisms.
Solution Approach 2:
The patent changes the curvature parameter of the liquid lens by applying different voltages. This allows continuous adjustment of the lens focal length through electrical control, enabling focus adjustment in a compact form factor without mechanical movement.
2Measurement precision
If a sensor unit is added to sense lens curvature, then the curvature sensing accuracy is improved, but the device complexity increases
Solution Approach 1:
The liquid lens structure itself serves as the sensing element. The liquid lens includes a first electrode and a second electrode with different areas, forming a capacitor where the capacitance directly reflects the lens curvature. This self-sensing mechanism eliminates the need for separate complex curvature sensors.
Solution Approach 2:
The electrode structure of the liquid lens performs dual functions: it controls the liquid lens curvature through voltage application and simultaneously serves as a sensing element to detect the curvature via capacitance measurement. This multi-functionality reduces overall system complexity.
3Speed
If the lens driver uses switching elements for electrical signal control, then the curvature variation speed is improved, but the detection precision may be affected by switching operations
Solution Approach 1:
The patent employs periodic switching operations to apply electrical signals to the liquid lens. The switching elements (first and second switching elements) are controlled in a periodic manner to adjust the curvature, while the capacitance sensing is performed at appropriate intervals to avoid interference from switching transients.
Solution Approach 2:
The patent performs preliminary actions by pre-charging or pre-discharging capacitors before switching operations to minimize voltage spikes and transient effects that could interfere with curvature sensing. This ensures that the capacitance measurement is not affected by switching operations.
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 quick and accurate focus adjustment and optical image stabilization in small devices by varying the liquid lens curvature based on sensed capacitance, reducing the need for physical lens movement and enhancing stabilization capabilities.
Implementation Method 1
a lens driver to apply an electrical signal to a liquid lens
Implementation Method 2
the curvature of the lens may be accurately detected by sensing a capacitance corresponding to the area of the boundary region between the insulator on the electrode and the electroconductive aqueous solution in the liquid lens
Data Source
Figure 1a~1b
Figure 2(a)~2(c)
Figure 3a(a)~3a(c)
AI summary
The present invention relates to a lens curvature variation apparatus. The lens curvature variation apparatus according to an embodiment is a lens curvature variation apparatus for varying a curvature of a liquid lens which is variable based on an applied electrical signal. The lens curvature variation apparatus includes a lens driver to apply the electrical signal to the liquid lens, a sensor unit to sense the curvature of the liquid lens formed based on the electrical signal, and a controller to control the lens driver to form a target curvature of the liquid lens based on the sensed curvature, wherein the lens driver supplies the electrical signal to the liquid lens according to a switching operation of a switching element, and includes a detection element connected to one end of the switching element, wherein the sensor unit senses an electrical signal detected by the detection element. Thereby, the curvature of the lens can be sensed quickly and accurately.