Mobile Lens Unit Position Detection via Conductive Contact

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Solution Overview

Problem

Existing mobile lens units face challenges in accurately determining the required current level to move the lens barrel to a specific position due to factors like orientation, spring force, and friction, making it difficult to achieve precise lens positioning without bulky and costly feedback systems.

Innovation Solution

A mobile lens unit with a motor-driven lens barrel that uses conductive rings and a processor to detect electrical contact changes, allowing for proportional displacement based on electrical signal levels, enabling precise current determination for desired lens positions with minimal circuitry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a feedback loop with position sensor (laser/LED and light detector) is used to detect lens barrel position, then measurement precision of lens position is improved, but device complexity and cost increase due to bulky components and additional circuitry

Engineering Contradiction:
Improvelens position detection accuracyVSAvoidsystem structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the detection function from a separate bulky position sensor system and integrates it into the existing motor structure. The coil serves dual purposes: as the actuating element for motor operation and as the detection element for position sensing, eliminating the need for additional laser/LED components and light detectors.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The coil is designed to perform multiple functions: it acts as both the electromagnetic actuator for moving the lens barrel and the detection sensor for determining lens barrel position. This multi-functionality reduces component count and simplifies the overall system structure while maintaining measurement precision.

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

2Device complexity

If no position detection system is used, then device complexity is reduced, but manufacturing precision of lens positioning deteriorates due to inability to compensate for variations in spring force, friction, and orientation

Engineering Contradiction:
Improvesystem structure simplicityVSAvoidlens position accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the processor continuously monitors the electrical signal level corresponding to lens barrel position and adjusts the motor control accordingly. This feedback loop compensates for variations in spring force, friction, and gravitational effects, maintaining manufacturing precision without requiring complex external sensors.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses its own motor coil as the detection sensor, eliminating the need for separate detection components. The processor utilizes electrical signal characteristics from the motor operation itself to determine position, allowing the system to self-monitor and self-correct positioning accuracy.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If traditional position sensors are used, then measurement precision is improved, but ease of manufacture deteriorates due to high cost and limited space compatibility

Engineering Contradiction:
Improveposition detection accuracyVSAvoidproduction cost and assembly complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent merges the motor coil and position detection sensor into a single integrated component. The same coil that generates electromagnetic force for motor operation also serves as the detection sensor, reducing component count, lowering production costs, and simplifying assembly while maintaining measurement precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent replaces expensive, bulky position sensors with a cost-effective solution using the existing motor coil and simple electrical signal monitoring. This approach significantly reduces component cost and makes the system more compatible with space-constrained mobile device manufacturing.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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 solution allows for accurate and efficient determination of the required current levels for lens positioning, reducing the need for bulky feedback systems and enabling precise control of lens displacement with minimal additional components, thus improving the accuracy and cost-effectiveness of lens positioning.

Implementation Method 1

When current is applied to the coil, due to electromagnetic force generated by the current flow in a magnetic field, the lens barrel moves towards the top of the housing, counteracting the force of the springs 116, 118.

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

a first conductor fixed to the lens barrel and arranged to make electrical contact with a second conductor when said lens barrel is at one of said initial position and said maximum displacement

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP1998202B1Mobile lens unit with detection device
Publication Date: 2013.12.18 STMICROELECTRONICS (GRENOBLE) SAS
  • EP1998202B1 patent drawingFigure 1~2B
  • EP1998202B1 patent drawingFigure 3A~4
  • EP1998202B1 patent drawingFigure 5

AI summary

The invention concerns a lens unit including a lens barrel (202) for receiving at least one lens (204, 206, 208), a motor (210, 215) arranged to displace the lens barrel between an initial position and a maximum displacement, wherein the displacement of a lens barrel is proportional to the level of an electrical signal applied to the motor when the electrical signal is between first and second levels, the first level corresponding to a level for starting movement of the lens barrel from the initial position and the second level corresponding to a level for bringing the lens barrel to the maximum displacement; a first conductor (222) fixed to the lens barrel and arranged to make electrical contact with a second conductor (224) when said lens barrel is at one of said initial position and said maximum displacement; and a processor arranged to detect a change in the contact situation between the first and second conductive surfaces, to determine one of said first and second levels based on level of the electrical signal at the time of the change and to generate, based on said determined level, a level of said electrical signal for a desired displacement.