Laser Speckle Force Sensing Without Contact Wiring

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Solution Overview

Problem

Conventional contact-based force sensors are inflexible, costly, and sensitive to environmental exposure, making them unsuitable for scalable and robust force sensing in various applications, particularly in scenarios where wiring or battery-powered systems are impractical.

Innovation Solution

Non-contact force sensing systems utilize laser speckle imaging to detect surface deformations caused by applied forces, analyzing laser speckle motion to determine force through processes such as speckle velocity estimation and integral calculation, enabling force sensing without physical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If contact-based force sensors are used, then force sensing capability is achieved, but device complexity and cost increase due to wiring and battery-powered systems

Engineering Contradiction:

Improveforce sensing capabilityVSAvoidwiring and battery-powered systems

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces contact-based mechanical force sensors with a non-contact optical system using laser speckle imaging. The laser projects speckle patterns onto the surface, and camera captures the patterns. When force is applied causing surface deformation, the speckle patterns shift. By tracking these shifts, the system measures force without physical contact, eliminating wiring and power requirements while maintaining force sensing capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system creates an optical copy of the surface deformation through laser speckle patterns. Instead of directly measuring force with physical sensors, the laser creates a speckle pattern that copies the surface topology. When the surface deforms under force, the speckle pattern copies this deformation, allowing indirect measurement of force through optical field analysis rather than direct mechanical contact.

Inventive Principle:

Principle #26Copying

2Measurement precision

If contact-based sensors are deployed, then force measurement is possible, but scalability and ease of deployment deteriorate due to installation and maintenance costs

Engineering Contradiction:

Improveforce measurementVSAvoidscalability and deployment

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent replaces mechanical force sensors with a non-contact optical system using laser speckle imaging. The laser projects speckle patterns onto the surface, and camera captures the patterns. When force is applied causing surface deformation, the speckle patterns shift. By tracking these shifts, the system measures force without physical contact, eliminating wiring and power requirements while maintaining force sensing capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If conventional force sensors are used, then force sensing is achieved, but adaptability to different environments worsens due to sensitivity to exposure and hardening requirements

Engineering Contradiction:

Improveforce sensingVSAvoidenvironmental exposure sensitivity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 approach provides a cost-effective, scalable, and robust method for force sensing, capable of detecting minute deformations and estimating force accurately without the need for physical contact, suitable for diverse interactive systems and environments.

Implementation Method 1

a laser source that illuminates a surface with a laser

Methodology Applied

Scientific EffectLaser: Laser

Implementation Method 2

analyzing the several images of the video to determine laser speckle motion due to surface deformations

Methodology Applied

Scientific EffectLaser speckle:

Implementation Method 3

a camera that captures video including several images of the surface

Methodology Applied

Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 4

analyzing the several images of the video to determine laser speckle motion due to surface deformations to the surface; and determining an applied force on the surface based on the analysis

Methodology Applied

Scientific EffectLaser speckle motion:

Data Source

PatentUS20260063483A1Systems and Methods of Non-Contact Force Sensing

Publication Date: 2026.03.05 RGT UNIV OF CALIFORNIA

AI summary

Systems and methods of non-contact force sensing are described. An embodiment includes a non-contact force sensing system, that includes: a laser source that illuminates a surface with a laser; a camera that captures video that includes several images of the surface; a process that includes: analyzing the images of the video to determine laser speckle motion due to surface deformations to the surface; and determining an applied force on the surface based on the analysis.