Liquid Lens Image Capture Device with Barrel Support

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Solution Overview

Problem

Existing image capture devices for coded optical information, such as bar code readers, face limitations in depth of field and decoding time due to the complexity and cost of traditional focusing systems, particularly with the use of piezoelectric and voice coil actuators, which are unreliable and have long response times.

Innovation Solution

Integration of a liquid lens with a compact and economical electro-optical element that combines diaphragm and electrical contact functions, using a barrel to support the liquid lens and conductor elements for improved assembly reliability and repeatability, along with a simplified H-bridge circuit for driving the liquid lens with resistors instead of power switches, reducing complexity and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional focusing systems with piezoelectric or voice coil actuators are used, then focusing capability is achieved, but reliability deteriorates and response time increases

Engineering Contradiction:
ImprovereliabilityVSAvoidresponse time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical focusing systems (piezoelectric actuators, voice coils) with a liquid lens system that uses electrical fields to change the refractive index of the lens material. This substitution eliminates mechanical moving parts, thereby improving reliability and reducing response time while maintaining focusing capability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state parameter of the lens material from solid/mechanical to liquid/electrical control. By applying voltage to change the refractive index of the liquid lens medium, the system achieves focusing without mechanical movement, resolving the contradiction between reliability and response time.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple image capture modules with differently focused optics are provided, then depth of field is increased, but device complexity and cost increase

Engineering Contradiction:
Improvedepth of fieldVSAvoidcomplexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Instead of providing multiple static image capture modules with fixed focal lengths, the patent employs a single dynamic liquid lens that can electronically adjust its focal length in real-time. This dynamic adjustment capability allows one module to replace multiple modules, reducing complexity while maintaining versatile depth of field coverage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The liquid lens system provides multi-functionality by enabling a single image capture module to perform focusing at multiple different distances through electrical control. This universal focusing capability eliminates the need for multiple specialized modules, thereby reducing device complexity and cost.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If electric motors are used to physically move optics for focusing, then focusing capability is achieved, but device complexity and cost increase

Engineering Contradiction:
Improvefocusing capabilityVSAvoidcomplexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces electric motors that physically move optical components with an electrical field-based liquid lens system. This substitution eliminates mechanical actuation mechanisms, reducing device complexity and cost while maintaining ease of operation through simple electrical control signals.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary substance (liquid lens medium) that responds to electrical fields to achieve focusing. This intermediary approach avoids direct mechanical coupling between control electronics and optical components, thereby simplifying the overall system architecture and reducing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

The solution provides a compact, reliable, and cost-effective image capture module with improved depth of field and faster decoding times, enhancing the performance of optical code readers by stabilizing the liquid lens and optimizing the drive circuit for efficient operation.

Implementation Method 1

a liquid lens (16) having a variable focal length, in particular an autofocus liquid lens

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

a drive circuit (18) for driving said liquid lens, in particular comprising an H-bridge circuit

Methodology Applied
Scientific EffectElectro-optic modulation: Electro-Optic Effects

Data Source

PatentEP2382502B1Liquid lens image capture device
Publication Date: 2019.04.17 DATALOGIC IP TECH
  • EP2382502B1 patent drawingFigure 1
  • EP2382502B1 patent drawingFigure 2
  • EP2382502B1 patent drawingFigure 3

AI summary

An image capture module (10), comprising a liquid lens (16) having a first and a second electrode (38, 48), a first and a second conductor element (34, 44) in electrical contact with said first and second electrode (38, 48), respectively, said first and second conductor elements (34, 44) being each intended for connection with a voltage generator (18) for driving the liquid lens (16), wherein the first conductor element (34) comprises an electrically conductive body having a peripheral region (36) for contact with the first electrode (38) of the liquid lens (16), and having a light diaphragm aperture (40) in a central region thereof.