Dynamic Laser Scan Angle Control for Consistent Signal Bandwidth

Solution Overview

Problem

Conventional laser scanning systems face challenges in maintaining consistent signal bandwidth and depth of field across varying distances, leading to increased complexity and cost due to the need for additional signal processing and varying scan line lengths.

Innovation Solution

A hand-supportable laser scanning system that dynamically adjusts the scan sweep angle based on detected or estimated object distance, using a system controller and drive current to maintain a constant scan line length and signal bandwidth by controlling the electromagnetic coil's drive current, thereby optimizing scan line length and depth of field performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the laser beam scans an object at a long distance in a fixed scan speed system, then the velocity of the laser beam across the object increases, but the signal amplitude becomes weak and the signal frequency bandwidth becomes very high

Engineering Contradiction:

Improvelaser beam velocity across objectVSAvoidsignal amplitude strength

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The patent implements dynamic scan speed adjustment based on detected object distance. The controller modifies the scan speed parameter in real-time according to the measured range, transitioning from a fixed scan speed system to a variable one. This allows the system to optimize signal characteristics for each distance, preventing excessive bandwidth expansion and maintaining reliable signal levels.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the scan speed parameter dynamically based on object distance measurements. By adjusting this key parameter according to range conditions, the system adapts its operational characteristics to maintain optimal signal quality across varying distances, resolving the contradiction between beam velocity and signal reliability.

Inventive Principle:

Principle #35Parameter changes

2Speed

If the laser beam scans an object at a long distance in a fixed scan speed system, then the velocity of the laser beam across the object increases, but the signal frequency bandwidth becomes very high requiring additional signal processing

Engineering Contradiction:

Improvelaser beam velocity across objectVSAvoidsignal processing bandwidth requirements

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent implements dynamic scan speed adjustment based on detected object distance. The controller modifies the scan speed parameter in real-time according to the measured range, transitioning from a fixed scan speed system to a variable one. This allows the system to optimize signal characteristics for each distance, preventing excessive bandwidth expansion and maintaining reliable signal levels.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the scan speed parameter dynamically based on object distance measurements. By adjusting this key parameter according to range conditions, the system adapts its operational characteristics to maintain optimal signal quality across varying distances, resolving the contradiction between beam velocity and signal reliability.

Inventive Principle:

Principle #35Parameter changes

3Speed

If the laser beam scans an object at a short distance in a fixed scan speed system, then the velocity of the laser beam across the object decreases, but the signal frequency bandwidth becomes relatively lower and signal amplitude becomes strong

Engineering Contradiction:

Improvelaser beam velocity across objectVSAvoiddepth of field performance consistency

Core Design Contradiction:

SpeedVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic scan speed adjustment based on detected object distance. The controller modifies the scan speed parameter in real-time according to the measured range, transitioning from a fixed scan speed system to a variable one. This allows the system to optimize signal characteristics for each distance, preventing excessive bandwidth expansion and maintaining reliable signal levels.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the scan speed parameter dynamically based on object distance measurements. By adjusting this key parameter according to range conditions, the system adapts its operational characteristics to maintain optimal signal quality across varying distances, resolving the contradiction between beam velocity and signal reliability.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If the scan line length varies with distance in a conventional system, then the system can cover different ranges, but the depth of field performance deteriorates and system complexity increases

Engineering Contradiction:

Improvescanning range coverageVSAvoiddepth of field performance

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent implements dynamic scan angle adjustment based on detected object distance. The controller modifies the scan angle parameter in real-time according to the measured range, allowing the system to maintain a substantially constant scan line length on the target object regardless of distance. This dynamic adaptation resolves the contradiction between scanning range coverage and depth of field performance consistency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the scan angle parameter dynamically based on object distance measurements. By adjusting this key parameter according to range conditions, the system maintains consistent scan line length and depth of field performance across varying distances, enabling versatile range coverage without performance deterioration.

Inventive Principle:

Principle #35Parameter changes

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 system achieves improved depth of field performance in both near-field and far-field scanning, maintaining consistent scan line lengths and signal bandwidth, reducing system complexity and cost by automatically adjusting the scan angle in response to object distance.

Implementation Method 1

a laser source for generating and projecting a laser scanning beam across a scanning field

Methodology Applied

Scientific EffectLaser: Laser

Implementation Method 2

a scanning mechanism with an electromagnetic coil for deflecting the laser beam through a scan angle, alpha, relative to an axis perpendicular to the scan line

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentUS10049245B2Laser scanning code symbol reading system providing control over length of laser scan line projected onto a scanned object using dynamic range-dependent scan angle control

Publication Date: 2018.08.14 METROLOGIC INSTRUMENTS INC

AI summary

Method of and system for reading bar code symbols using a hand-supportable laser scanning bar code symbol reading system supporting an improved level control over the length of laser scan lines projected onto scanned objects, at any instant in time, in a manner dependent the detected location, distance or range of the scanned object in the scanning field of the system during system operation. The length characteristics of the laser scan line are controlled by setting the laser scan sweep angle as a function of detected or estimated distance or range of the object from the system. In the illustrative embodiment, the laser scan sweep angle is controlled by supplying a drive current to the scanning mechanism, as a function of detected or estimated distance or range of the object from the scanning system.