Liquid Lens Variable Focal Length Control via Contrast Analysis
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Solution Overview
Problem
Conventional variable focal length lens devices require cumbersome preparatory work for users to define the focal length for image detection, involving provisional measurements and visual checks, which is inefficient.
Innovation Solution
A method and device that automatically define a focal length responsive to a measured object by detecting images at multiple candidate planes with varying focal lengths, calculating contrast, and selecting the appropriate plane for focus, using a liquid lens system and image detector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a variable focal length lens device uses a liquid lens system with sinusoidal AC drive signal, then the focal length changes sinusoidally allowing image detection at multiple focal lengths, but the user must perform cumbersome preparatory work including provisional measurements and visual checks to define the focal length for image detection
Solution Approach 1:
The system performs automatic focal length definition by autonomously capturing images at multiple candidate planes, calculating contrast for each plane, and selecting the optimal focal length without requiring user intervention for provisional measurements and visual checks
Solution Approach 2:
The system pre-defines multiple candidate planes at different focal lengths and automatically captures images at these planes before final image detection, enabling the user to directly select from pre-prepared focal length options without performing preparatory measurements
2Productivity
If the system captures images at multiple candidate planes to enable automatic focal length definition, then processing efficiency improves, but the number of image capture operations and data processing steps increases
Solution Approach 1:
The system replaces manual mechanical adjustment of focal length with automated electronic control, using a processor to automatically capture images at multiple candidate planes, calculate contrast values, and determine the optimal focal length without requiring manual intervention
Solution Approach 2:
The system automatically varies the focal length parameter by adjusting the drive signal amplitude to the liquid lens system, capturing images at multiple predefined candidate planes with different focal lengths, and selects the optimal plane based on contrast calculation
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 automatic focal length definition without user-intensive preparatory work, allowing for simultaneous image detection at multiple focal lengths and improving processing efficiency by selecting focused surfaces based on contrast analysis.
Implementation Method 1
concentric circular regions having different refractive indexes are formed centered on a center axis line of the oscillating member. In this state, when light transits along the center axis line of the oscillating member, the light travels along a path that either disperses or converges the light in accordance with the refractive index of each concentric circular region.
Data Source
AI summary
In a variable focal length lens control method, a plurality of candidate planes are defined at different focal lengths of a variable focal length lens, an image of a measurable object is detected by an image detector at each of the candidate planes, contrast in each of the detected images is calculated, any of the candidate planes is selected based on the contrast, and a focal length of the selected candidate plane is defined for a lens controller.